Upconversion microparticles as time-resolved luminescent probes for multiphoton microscopy: desired signal extraction from the streaking effect

NASA Astrophysics Data System (ADS)

Pominova, Daria V.; Ryabova, Anastasia V.; Grachev, Pavel V.; Romanishkin, Igor D.; Kuznetsov, Sergei V.; Rozhnova, Julia A.; Yasyrkina, Daria S.; Fedorov, Pavel P.; Loschenov, Victor B.

2016-09-01

The great interest in upconversion nanoparticles exists due to their high efficiency under multiphoton excitation. However, when these particles are used in scanning microscopy, the upconversion luminescence causes a streaking effect due to the long lifetime. This article describes a method of upconversion microparticle luminescence lifetime determination with help of modified Lucy-Richardson deconvolution of laser scanning microscope (LSM) image obtained under near-IR excitation using nondescanned detectors. Determination of the upconversion luminescence intensity and the decay time of separate microparticles was done by intensity profile along the image fast scan axis approximation. We studied upconversion submicroparticles based on fluoride hosts doped with Yb3+-Er3+ and Yb3+-Tm3+ rare earth ion pairs, and the characteristic decay times were 0.1 to 1.5 ms. We also compared the results of LSM measurements with the photon counting method results; the spread of values was about 13% and was associated with the approximation error. Data obtained from live cells showed the possibility of distinguishing the position of upconversion submicroparticles inside and outside the cells by the difference of their lifetime. The proposed technique allows using the upconversion microparticles without shells as probes for the presence of OH- ions and CO2 molecules.

A near-infrared luminescent Mn2+-doped NaYF4:Yb,Tm/Fe3+ upconversion nanoparticles redox reaction system for the detection of GSH/Cys/AA.

PubMed

Zhang, Liping; Ling, Bo; Wang, Lun; Chen, Hongqi

2017-09-01

An upconversion luminescence method was developed for the determination of glutathione (GSH), L-cysteine (Cys) or L-ascorbic acid (AA) based on redox reaction. We synthesized poly(acrylic acid) (PAA)-modified Mn 2+ -doped NaYF 4 :Yb,Tm upconversion nanoparticles (UCNPs), and the luminescence of these UCNPs was effectively quenched due to their carboxyl groups coordinating with Fe 3+ to form a UCNPs/Fe 3+ system. GSH, Cys or AA reduced Fe 3+ to Fe 2+ , which induced the luminescence recovery of the UCNPs. Under the optimized conditions, wide linear concentration ranges from 0.25-300μM for GSH, 0.5-875μM for Cys and 0.5-350μM for AA were found, and the detection limits (3S/K) were 0.2μM, 0.5μM and 0.2μM, respectively. Thus, the UCNPs/Fe 3+ system was successfully applied for sensing GSH, Cys or AA. Copyright © 2017 Elsevier B.V. All rights reserved.

Deep Photoacoustic/Luminescence/Magnetic Resonance Multimodal Imaging in Living Subjects Using High-Efficiency Upconversion Nanocomposites.

PubMed

Liu, Yu; Kang, Ning; Lv, Jing; Zhou, Zijian; Zhao, Qingliang; Ma, Lingceng; Chen, Zhong; Ren, Lei; Nie, Liming

2016-08-01

A gadolinium-doped multi-shell upconversion nanoparticle under 800 nm excitation is synthesized with a 10-fold fluorescence-intensity enhancement over that under 980 nm. The nanoformulations exhibit excellent photoacoustic/luminescence/magnetic resonance tri-modal imaging capabilities, enabling visualization of tumor morphology and microvessel distribution at a new imaging depth. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High efficiency upconversion nanophosphors for high-contrast bioimaging

NASA Astrophysics Data System (ADS)

Alkahtani, Masfer H.; Alghannam, Fahad S.; Sanchez, Carlos; Gomes, Carmen L.; Liang, Hong; Hemmer, Philip R.

2016-12-01

Upconversion nanoparticles (UCNPs) are of interest because they allow suppression of tissue autofluorescence and are therefore visible deep inside biological tissue. Compared to upconversion dyes, UCNPs have a lower pump intensity threshold, better photostability, and less toxicity. Recently, YVO4: Er+3, Yb+3 nanoparticles were shown to exhibit strong up-conversion luminescence with a relatively low 10 kW cm-2 excitation intensity even in water, which makes them excellent bio-imaging candidates. Herein, we investigate their use as internal probes in insects by injecting YVO4 : Er+3, Yb+3 nanoparticles into fire ants as a biological model, and obtain 2D optical images with 980 nm illumination. High-contrast images with high signal-to-noise ratio are observed by detecting the up-conversion fluorescence as the excitation laser is scanned.

Advances in highly doped upconversion nanoparticles.

PubMed

Wen, Shihui; Zhou, Jiajia; Zheng, Kezhi; Bednarkiewicz, Artur; Liu, Xiaogang; Jin, Dayong

2018-06-20

Lanthanide-doped upconversion nanoparticles (UCNPs) are capable of converting near-infra-red excitation into visible and ultraviolet emission. Their unique optical properties have advanced a broad range of applications, such as fluorescent microscopy, deep-tissue bioimaging, nanomedicine, optogenetics, security labelling and volumetric display. However, the constraint of concentration quenching on upconversion luminescence has hampered the nanoscience community to develop bright UCNPs with a large number of dopants. This review surveys recent advances in developing highly doped UCNPs, highlights the strategies that bypass the concentration quenching effect, and discusses new optical properties as well as emerging applications enabled by these nanoparticles.

Controlled synthesis and luminescence properties of β-NaGdF4: Yb3+, Er3+ upconversion nanoparticles

NASA Astrophysics Data System (ADS)

Zhang, Yueli; Yao, Lu; Xu, Dekang; Lin, Hao; Yang, Shenghong

2018-06-01

β-NaGdF4:Yb3+,Er3+ upconversion (UC) nanoparticles (UCNPs) were prepared by a facile hydrothermal process with the assistance of sodium ethylene diaminetetraacetate salt (EDTA-2Na). The morphologies of the β-NaGdF4 UCNPs were controlled by changing the doses of EDTA-2Na and NaOH in precursor. With increasing concentration of EDTA-2Na in precursor, the size of crystals decreased, resulting in the decreasing of luminescence intensity. With increasing concentration of NaOH in precursor, the morphology became more homogeneous. However, due to the reduction of grain size and crystal quality, the luminescence intensity decreased. Nevertheless, the above results demonstrated a simple route to fabricate homogeneous UCNPs.

Perspectives and challenges of photon-upconversion nanoparticles - Part I: routes to brighter particles and quantitative spectroscopic studies.

PubMed

Resch-Genger, Ute; Gorris, Hans H

2017-10-01

Lanthanide-doped photon-upconversion nanoparticles (UCNPs) have been the focus of many research activities in materials and life sciences in the last 15 years because of their potential to convert light between different spectral regions and their unique photophysical properties. To fully exploit the application potential of these fascinating nanomaterials, a number of challenges have to be overcome, such as the low brightness, particularly of small UCNPs, and the reliable quantification of the excitation-power-density-dependent upconversion luminescence. In this series of critical reviews, recent developments in the design, synthesis, optical-spectroscopic characterization, and application of UCNPs are presented with special focus on bioanalysis and the life sciences. Here we guide the reader from the synthesis of UCNPs to different concepts to enhance their luminescence, including the required optical-spectroscopic assessment to quantify material performance; surface modification strategies and bioanalytical applications as well as selected examples of the use of UCNPs as reporters in different assay formats are addressed in part II. Future trends and challenges in the field of upconversion are discussed with special emphasis on UCNP synthesis and material characterization, particularly quantitative luminescence studies. Graphical Abstract Both synthesis and spectroscopy as well bioanalytical applications of UCNPs are driven and supported by COST Action CM1403 "The European Upconversion Network".

New nanoplatforms based on UCNPs linking with polyhedral oligomeric silsesquioxane (POSS) for multimodal bioimaging

NASA Astrophysics Data System (ADS)

Ge, Xiaoqian; Dong, Liang; Sun, Lining; Song, Zhengmei; Wei, Ruoyan; Shi, Liyi; Chen, Haige

2015-04-01

A new and facile method was used to transfer upconversion luminescent nanoparticles from hydrophobic to hydrophilic using polyhedral oligomeric silsesquioxane (POSS) linking on the surface of upconversion nanoparticles. In comparison with the unmodified upconversion nanoparticles, the POSS modified upconversion nanoplatforms [POSS-UCNPs(Er), POSS-UCNPs(Tm)] displayed good monodispersion in water and exhibited good water-solubility, while their particle size did not change substantially. Due to the low cytotoxicity and good biocompatibility as determined by methyl thiazolyl tetrazolium (MTT) assay and histology and hematology analysis, the POSS modified upconversion nanoplatforms were successfully applied to upconversion luminescence imaging of living cells in vitro and nude mouse in vivo (upon excitation at 980 nm). In addition, the doped Gd3+ ion endows the POSS-UCNPs with effective T1 signal enhancement and the POSS-UCNPs were successfully applied to in vivo magnetic resonance imaging (MRI) for a Kunming mouse, which makes them potential MRI positive-contrast agents. More importantly, the corner organic groups of POSS can be easily modified, resulting in kinds of POSS-UCNPs with many potential applications. Therefore, the method and results may provide more exciting opportunities for multimodal bioimaging and multifunctional applications.A new and facile method was used to transfer upconversion luminescent nanoparticles from hydrophobic to hydrophilic using polyhedral oligomeric silsesquioxane (POSS) linking on the surface of upconversion nanoparticles. In comparison with the unmodified upconversion nanoparticles, the POSS modified upconversion nanoplatforms [POSS-UCNPs(Er), POSS-UCNPs(Tm)] displayed good monodispersion in water and exhibited good water-solubility, while their particle size did not change substantially. Due to the low cytotoxicity and good biocompatibility as determined by methyl thiazolyl tetrazolium (MTT) assay and histology and hematology analysis, the POSS modified upconversion nanoplatforms were successfully applied to upconversion luminescence imaging of living cells in vitro and nude mouse in vivo (upon excitation at 980 nm). In addition, the doped Gd3+ ion endows the POSS-UCNPs with effective T1 signal enhancement and the POSS-UCNPs were successfully applied to in vivo magnetic resonance imaging (MRI) for a Kunming mouse, which makes them potential MRI positive-contrast agents. More importantly, the corner organic groups of POSS can be easily modified, resulting in kinds of POSS-UCNPs with many potential applications. Therefore, the method and results may provide more exciting opportunities for multimodal bioimaging and multifunctional applications. Electronic supplementary information (ESI) available: Schematic illustration of the formation of POSS-UCNPs. TEM images of NaYF4:Yb,Tm and NaYF4:Yb,Tm@NaGdF4 nanoparticles in cyclohexane; the TEM image of POSS-UCNPs(Tm) in water. DLS of POSS-UCNPs(Tm) in water. The energy dispersive X-ray (EDX) spectrum of POSS-UCNPs(Er). XPS of POSS-UCNPs(Er); XPS of Si element. UCL spectra of POSS-UCNPs(Er) in physiology saline as a function of time. UCL spectra of NaYF4:Yb,Tm@NaGdF4 [UCNPs(Tm)] and POSS-UCNPs(Tm), excited with a 980 nm laser (100 mW cm-2). In vivo UCL imaging of Kunming mice after intravenous injection with POSS-UCNPs(Tm) at different time points. See DOI: 10.1039/c5nr00950b

Enhanced upconversion emission in colloidal (NaYF4:Er(3+))/NaYF4 core/shell nanoparticles excited at 1523 nm.

PubMed

Shao, Wei; Chen, Guanying; Damasco, Jossana; Wang, Xianliang; Kachynski, Aliaksandr; Ohulchanskyy, Tymish Y; Yang, Chunhui; Ågren, Hans; Prasad, Paras N

2014-03-15

In this work, we report on efficient visible and near-IR upconversion emissions in colloidal hexagonal-phase core/shell NaYF4:Er(3+)/NaYF4 nanoparticles (∼38  nm) under IR laser excitation at 1523 nm. Varying amounts of Er(3+) dopants were introduced into the core NaYF4:Er(3+) nanoparticles, revealing an optimized Er(3+) concentration of 10% for the highest luminescent efficiency. An inert epitaxial shell layer of NaYF4 grown onto the core of the NaYF4:Er(3+) 10% nanoparticle increased its upconversion emission intensity fivefold due to suppression of surface-related quenching mechanisms, yielding the absolute upconversion efficiency to be as high as ∼3.9±0.3% under an excitation density of 18  W/cm(2). The dependence of the intensity of upconversion emission peaks on laser excitation density in the core/shell nanoparticle displayed "saturation effects" at low excitation density in the range of 1.5-18  W/cm(2), which again demonstrates high upconversion efficiency.

Achieving high-efficiency emission depletion nanoscopy by employing cross relaxation in upconversion nanoparticles.

PubMed

Zhan, Qiuqiang; Liu, Haichun; Wang, Baoju; Wu, Qiusheng; Pu, Rui; Zhou, Chao; Huang, Bingru; Peng, Xingyun; Ågren, Hans; He, Sailing

2017-10-20

Stimulated emission depletion microscopy provides a powerful sub-diffraction imaging modality for life science studies. Conventionally, stimulated emission depletion requires a relatively high light intensity to obtain an adequate depletion efficiency through only light-matter interaction. Here we show efficient emission depletion for a class of lanthanide-doped upconversion nanoparticles with the assistance of interionic cross relaxation, which significantly lowers the laser intensity requirements of optical depletion. We demonstrate two-color super-resolution imaging using upconversion nanoparticles (resolution ~ 66 nm) with a single pair of excitation/depletion beams. In addition, we show super-resolution imaging of immunostained cytoskeleton structures of fixed cells (resolution ~ 82 nm) using upconversion nanoparticles. These achievements provide a new perspective for the development of photoswitchable luminescent probes and will broaden the applications of lanthanide-doped nanoparticles for sub-diffraction microscopic imaging.

Synthesis of NaYF4:Yb/Er/Gd up-conversion luminescent nanoparticles and luminescence resonance energy transfer-based protein detection

PubMed Central

Zhang, Jingpu; Mi, Congcong; Wu, Hongyan; Huang, Huaiqing; Mao, Chuanbin; Xu, Shukun

2012-01-01

High-quality NaYF4:Yb/Er/Gd up-conversion nanoparticles (UCNPs) were first synthesized by a solvothermal method using rare earth stearate, sodium fluoride, ethanol, water, and oleic acid as precursors. Doped Gd3+ ions can promote the transition of NaYF4 from cubic to hexagonal phase, shorten the reaction time, and reduce the reaction temperature without reducing the luminescence intensity of NaYF4:Yb/Er UCNPs. X-ray diffraction, infrared spectroscopy, transmission electron microscopy, and luminescence spectroscopy were applied to characterize the UCNPs. The nanoparticles exhibited small size and excellent green up-conversion photoluminescence, making them suitable for biological applications. After the surfaces of NaYF4:Yb/Er/Gd UCNPs were modified with amino groups through the Stöber method, they could be brought close enough to the analytically important protein called R-phycoerythrin (R-PE) bearing multiple carboxyl groups so that energy transfer could occur. A luminescence resonance energy transfer (LRET) system was developed using NaYF4:Yb/Er/Gd UCNPs as an energy donor and R-PE as an energy acceptor. As a result, a detection limit of R-PE of 0.5 μg/ml was achieved by the LRET system with a relative standard deviation of 2.0%. Although this approach was first used successfully to detect R-PE, it can also be extended to the detection of other biological molecules. PMID:22155069

Oligonucleotide Sensor Based on Selective Capture of Upconversion Nanoparticles Triggered by Target-Induced DNA Interstrand Ligand Reaction

PubMed Central

2017-01-01

We present a sensor that exploits the phenomenon of upconversion luminescence to detect the presence of specific sequences of small oligonucleotides such as miRNAs among others. The sensor is based on NaYF4:Yb,Er@SiO2 nanoparticles functionalized with ssDNA that contain azide groups on the 3′ ends. In the presence of a target sequence, interstrand ligation is possible via the click-reaction between one azide of the upconversion probe and a DBCO-ssDNA-biotin probe present in the solution. As a result of this specific and selective process, biotin is covalently attached to the surface of the upconversion nanoparticles. The presence of biotin on the surface of the nanoparticles allows their selective capture on a streptavidin-coated support, giving a luminescent signal proportional to the amount of target strands present in the test samples. With the aim of studying the analytical properties of the sensor, total RNA samples were extracted from healthy mosquitoes and were spiked-in with a specific target sequence at different concentrations. The result of these experiments revealed that the sensor was able to detect 10–17 moles per well (100 fM) of the target sequence in mixtures containing 100 ng of total RNA per well. A similar limit of detection was found for spiked human serum samples, demonstrating the suitability of the sensor for detecting specific sequences of small oligonucleotides under real conditions. In contrast, in the presence of noncomplementary sequences or sequences having mismatches, the luminescent signal was negligible or conspicuously reduced. PMID:28332400

Comparison of temperature sensing of the luminescent upconversion and ZnCdS nanoparticles

NASA Astrophysics Data System (ADS)

Yanina, I. Yu.; Volkova, E. K.; Sagaidachnaya, E. A.; Konyukhova, J. G.; Kochubey, V. I.; Tuchin, V. V.

2018-02-01

The luminescence spectra of upconversion nanoparticles (UCNPs) and ZnCdS nanoparticles (ZnCdSNPs) were measured and analyzed in a wide temperature range: from room to human body and further to a hyperthermic temperature resulting in tissue morphology change. The results show that the luminescence signal of UCNPs and ZnCdSNPs placed within the tissue is reasonably good sensitive to temperature change and accompanied by phase transitions of lipid structures of adipose tissue. The most likely that the multiple phase transitions are associated with the different components of fat cells, such as phospholipids of cell membrane and lipids of fat droplets. In the course of fat cell heating, lipids of fat droplet first transit from a crystalline form to a liquid crystal form and then to a liquid form, which is characterized by much less scattering. The results of phase transitions of lipids were observed as the changes in the slope of the temperature dependence of the intensity of luminescence of the film with nanoparticles embedded into tissue. The obtained results confirm a high sensitivity of the luminescent UCNPs and ZnCdSNPs to the temperature variations within thin tissue samples and show a strong potential for the controllable tissue thermolysis.

In vitro cell imaging using multifunctional small sized KGdF4:Yb3+,Er3+ upconverting nanoparticles synthesized by a one-pot solvothermal process

NASA Astrophysics Data System (ADS)

Wong, Hon-Tung; Tsang, Ming-Kiu; Chan, Chi-Fai; Wong, Ka-Leung; Fei, Bin; Hao, Jianhua

2013-03-01

Multifunctional KGdF4:18%Yb3+,2%Er3+ nanoparticles with upconversion fluorescence and paramagnetism are synthesized. The average sizes of the nanoparticles capped with branched polyethyleneimine (PEI) and 6-aminocaproic acid (6AA) are ~14 and ~13 nm, respectively. Our KGdF4 host does not exhibit any phase change with the decrease of particle size, which can prevent the detrimental significant decrease in upconversion luminescence caused by this effect observed in the well-known NaYF4 host. The branched PEI and 6AA capping ligands endow our nanoparticles with water-dispersibility and biocompatibility, which can favor internalization of our nanoparticles into the cytoplasm of HeLa cells and relatively high cell viability. The strong upconversion luminescence detected at the cytoplasm of HeLa cells incubated with the branched PEI-capped nanoparticles is probably attributed to the reported high efficiency of cellular uptake. The magnetic mass susceptibility of our nanoparticle is 8.62 × 10-5 emu g-1 Oe-1. This is the highest value ever reported in trivalent rare-earth ion-doped KGdF4 nanoparticles of small size (<=14 nm), and is very close to that of nanoparticles used as T1 contrast agents in magnetic resonance imaging. These suggest the potential of our KGdF4:Yb3+,Er3+ nanoparticles as small-sized multifunctional bioprobes.

Dye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging Applications

DOE PAGES

Wu, Xiang; Zhang, Yuanwei; Takle, Kendra; ...

2016-01-06

A near-infrared (NIR) dye-sensitized upconversion nanoparticles (UCNPs) can broaden the absorption range and boost upconversion efficiency of UCNPs. We achieved significantly enhanced upconversion luminescence in dye-sensitized core/active shell UCNPs via the doping of ytterbium ions (Yb 3+ ) in the UCNP shell, which bridged the energy transfer from the dye to the UCNP core. As a result, we synergized the two most practical upconversion booster effectors (dye-sensitizing and core/shell enhancement) to amplify upconversion efficiency. We also demonstrated two biomedical applications using these UCNPs. By using dye-sensitized core/active shell UCNP embedded poly(methyl methacrylate) polymer implantable systems, we successfully shifted the optogeneticmore » neuron excitation window to a biocompatible and deep tissue penetrable 800 nm wavelength. Furthermore, UCNPs were water-solubilized with Pluronic F127 with high upconversion efficiency and can be imaged in a mouse model.« less

NIR Ratiometric Luminescence Detection of pH Fluctuation in Living Cells with Hemicyanine Derivative-Assembled Upconversion Nanophosphors.

PubMed

Li, Haixia; Dong, Hao; Yu, Mingming; Liu, Chunxia; Li, Zhanxian; Wei, Liuhe; Sun, Ling-Dong; Zhang, Hongyan

2017-09-05

It is crucial for cell physiology to keep the homeostasis of pH, and it is highly demanded yet challenging to develop luminescence resonance energy transfer (LRET)-based near-infrared (NIR) ratiometric luminescent sensor for the detection of pH fluctuation with NIR excitation. As promising energy donors for LRET, upconversion nanoparticles (UCNPs) have been widely used to fabricate nanosensors, but the relatively low LRET efficiency limits their application in bioassay. To improve the LRET efficiency, core/shell/shell structured β-NaGdF 4 @NaYF 4 :Yb,Tm@NaYF 4 UCNPs were prepared and decorated with hemicyanine dyes as an LRET-based NIR ratiometric luminescent pH fluctuation-nanosensor for the first time. The as-developed nanosensor not only exhibits good antidisturbance ability, but it also can reversibly sense pH and linearly sense pH in a range of 6.0-9.0 and 6.8-9.0 from absorption and upconversion emission spectra, respectively. In addition, the nanosensor displays low dark toxicity under physiological temperature, indicating good biocompatibility. Furthermore, live cell imaging results revealed that the sensor can selectively monitor pH fluctuation via ratiometric upconversion luminescence behavior.

Singlet oxygen generation of photosensitizers effectively activated by Nd3+-doped upconversion nanoparticles of luminescence intensity enhancing with shell thickness decreasing

NASA Astrophysics Data System (ADS)

Zou, Haixia; Jin, Fengmin; Song, Xiaoyan; Xing, Jinfeng

2017-04-01

The introduction of a thick shell structure has been widely used to enhance the emission intensity of upconversion nanoparticles (UCNPs). However, a thick shell could increase the distance between UCNPs and photosensitizers, which is not favourable to the generation of singlet oxygen (1O2) in photodynamic therapy (PDT) due to the low fluorescence resonance energy transfer (FRET) efficiency. In this study, we used a facile method to prepare UCNPs that the emission intensity could increase with the shell thickness decreasing, which facilitated the efficient FRET between UCNPs and photosensitizers. In detail, the Nd3+-doped UCNPs with different dopant concentration of Yb3+ were prepared and characterized firstly. The Ir/g (intensity of red luminescence to green luminescence) was tuned to increase largely by precisely controlling Yb3+ concentration in core-shell, which could make UCNPs effectively activate methylene blue (MB). Then, a unique procedure was used to prepare NaYF4:Yb/Er/Nd@NaYF4:Nd (Yb3+:30%) core-shell nanoparticles with different shell thickness by tuning the amount of the core. The upconversion luminescence (UCL) intensity of those UCNPs enhanced dramatically with the shell thickness decreasing. Furthermore, UCNPs and MB were encapsulated into SiO2 nanoparticles. FRET efficiency between UCNPs and MB largely increased with the shell thickness of UCNPs decreasing. Correspondingly, the efficiency of 1O2 generation obviously increased. We provided a new method to optimize the UCL intensity and FRET efficiency at the same time to produce 1O2 efficiently.

Effect of various surfactants on changes in the emission color chromaticity in upconversion YVO4: Yb3+, Er3+ nanoparticles

NASA Astrophysics Data System (ADS)

Woźny, Przemysław; Szczeszak, Agata; Lis, Stefan

2018-02-01

YVO4: Yb3+,Er3+ upconverting nanocrystals were synthesized via a hydrothermal method using different compounds as surfactants. Structure and morphology of the nanocrystals were investigated by X-ray diffraction and transmission electron microscopy. Tetragonal crystal structure of the nanocrystals appeared irrespective of the type of surfactant used. The average crystallite size was estimated by TEM images. The obtained products were composed of small nanoparticles, in the size range of 10-60 nm, depending on the surfactant used. The morphology of the nanoparticles was also regulated by the type of surfactant. Spectroscopic analysis of the materials obtained was carried out by measuring the emission and excitation spectra and the intensity of luminescence as a function of laser energy and luminescence decays. The nanocrystals prepared exhibited a green upconversion emission attributed to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+, under NIR (985 nm) pulse laser irradiation, and their emission lifetimes were in the range 3.84-4.90 μs. On the basis of the spectroscopic investigation, the upconversion mechanism was proposed and chromaticity coordinates were calculated. Surfactants were found to influence on chromaticity of luminescence.

Synthesis and application of nanohybrids based on upconverting nanoparticles and polymers.

PubMed

Cheng, Ziyong; Lin, Jun

2015-05-01

Lanthanide-doped upconversion nanoparticles (UCNPs) have been an emerging and exciting research field in recent years due to their unique luminescent properties of converting near-infrared light to shorter wavelength radiation. UCNPs offer excellent prospects in luminescent labeling, displays, bioimaging, bioassays, drug delivery, sensors, and anticounterfeiting applications. Along with the abundant studies and rapid progress in this area, UCNPs are promising to be a new class of luminescent probe owing to their special advantages over the conventional organic dyes and quantum dots. Among them, polymers play an important role to improve properties or endow new function of UCNPs such as for matrix materials, water solubility, linking active targeting molecules, biocompatibility, and stimuli-responsive behavior. This article briefly reviews the compositions, optical mechanisms, architectures of upconversion nanocrystals and highlights the works on various functional UCNPs/polymer nanohybrids as well as many new interesting fruits in applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent Advances in Inorganic Nanoparticle-Based NIR Luminescence Imaging: Semiconductor Nanoparticles and Lanthanide Nanoparticles.

PubMed

Kim, Dokyoon; Lee, Nohyun; Park, Yong Il; Hyeon, Taeghwan

2017-01-18

Several types of nanoparticle-based imaging probes have been developed to replace conventional luminescent probes. For luminescence imaging, near-infrared (NIR) probes are useful in that they allow deep tissue penetration and high spatial resolution as a result of reduced light absorption/scattering and negligible autofluorescence in biological media. They rely on either an anti-Stokes or a Stokes shift process to generate luminescence. For example, transition metal-doped semiconductor nanoparticles and lanthanide-doped inorganic nanoparticles have been demonstrated as anti-Stokes shift-based agents that absorb NIR light through two- or three-photon absorption process and upconversion process, respectively. On the other hand, quantum dots (QDs) and lanthanide-doped nanoparticles that emit in NIR-II range (∼1000 to ∼1350 nm) were suggested as promising Stokes shift-based imaging agents. In this topical review, we summarize and discuss the recent progress in the development of inorganic nanoparticle-based luminescence imaging probes working in NIR range.

Delivery and reveal of localization of upconversion luminescent microparticles and quantum dots in the skin in vivo by fractional laser microablation, multimodal imaging, and optical clearing

NASA Astrophysics Data System (ADS)

Volkova, Elena K.; Yanina, Irina Yu; Genina, Elina A.; Bashkatov, Alexey N.; Konyukhova, Julia G.; Popov, Alexey P.; Speranskaya, Elena S.; Bucharskaya, Alla B.; Navolokin, Nikita A.; Goryacheva, Irina Yu.; Kochubey, Vyacheslav I.; Sukhorukov, Gleb B.; Meglinski, Igor V.; Tuchin, Valery V.

2018-02-01

Delivery and spatial localization of upconversion luminescent microparticles [Y2O3:Yb, Er] (mean size ˜1.6 μm) and quantum dots (QDs) (CuInS2/ZnS nanoparticles coated with polyethylene glycol-based amphiphilic polymer, mean size ˜20 nm) inside rat skin was studied in vivo using a multimodal optical imaging approach. The particles were embedded into the skin dermis to the depth from 300 to 500 μm through microchannels performed by fractional laser microablation. Low-frequency ultrasound was applied to enhance penetration of the particles into the skin. Visualization of the particles was revealed using a combination of luminescent spectroscopy, optical coherence tomography, confocal microscopy, and histochemical analysis. Optical clearing was used to enhance the image contrast of the luminescent signal from the particles. It was demonstrated that the penetration depth of particles depends on their size, resulting in a different detection time interval (days) of the luminescent signal from microparticles and QDs inside the rat skin in vivo. We show that luminescent signal from the upconversion microparticles and QDs was detected after the particle delivery into the rat skin in vivo during eighth and fourth days, respectively. We hypothesize that the upconversion microparticles have created a long-time depot localized in the laser-created channels, as the QDs spread over the surrounding tissues.

Tunable green/red luminescence by infrared upconversion in biocompatible forsterite nanoparticles with high erbium doping uptake

NASA Astrophysics Data System (ADS)

Zampiva, Rúbia Young Sun; Acauan, Luiz Henrique; Venturini, Janio; Garcia, Jose Augusto Martins; da Silva, Diego Silverio; Han, Zhaohong; Kassab, Luciana Reyes Pires; Wetter, Niklaus Ursus; Agarwal, Anuradha; Alves, Annelise Kopp; Bergmann, Carlos Pérez

2018-02-01

Nanoparticles represent a promising platform for diagnostics and therapy of human diseases. For biomedical applications, these nanoparticles are usually coated with photosensitizers regularly activated in a spectral window of 530-700 nm. The emissions at 530 nm (green) and 660 nm (red) are of particular interest for imaging and photodynamic therapy, respectively. This work presents the Mg2SiO4:Er3+ system, produced by reverse strike co-precipitation, with up to 10% dopant and no secondary phase formation. These nanoparticles when excited at 985 nm show upconversion emission with peaks around 530 and 660 nm, although excitation at 808 nm leads to only a single emission peak at around 530 nm. The direct upconversion of this biomaterial without a co-dopant, and its tunability by the excitation source, renders Mg2SiO4:Er3+ nanoparticles a promising system for biomedical applications.

Luminescence resonance energy transfer (LRET) aptasensor for ochratoxin A detection using upconversion nanoparticles

NASA Astrophysics Data System (ADS)

Jo, Eun-Jung; Byun, Ju-Young; Mun, Hyoyoung; Kim, Min-Gon

2017-07-01

We report an aptasensor for homogeneous ochratoxin A (OTA) detection based on luminescence resonance energy transfer (LRET). This system uses upconversion nanoparticles (UCNPs), such as NaYF4:Yb3+, Er 3+, as the donor. The aptamer includes the optimum-length linker (5-mer-length DNA) and OTA-specific aptamer sequences. Black hole quencher 1 (BHQ1), as the acceptor, was modified at the 3' end of the aptamer sequence. BHQ1 plays as a quencher in LRET aptasensor and shows absorption at 543 nm, which overlaps with well the emission of the UCNPs. When OTA is added, the BHQ1-labeled OTA aptamer was folded due to the formation of the G-quadruplex-OTA complex, which induced the BHQ1 close to the UCNPs. Consequently, resonance energy transfer between UCNPs (donor) and BHQ1 (acceptor) enables quenching of upconversion luminescence signals under laser irradiation of 980 nm. Our results showed that the LRET-based aptasensor allows specific OTA analysis with a limit of detection of 0.03 ng/mL. These results demonstrated that the OTA in diverse foods can be detected specifically and sensitively in a homogeneous manner.

Highly efficient upconversion luminescence in hexagonal NaYF4:Yb3+, Er3+ nanocrystals synthesized by a novel reverse microemulsion method

NASA Astrophysics Data System (ADS)

Gunaseelan, M.; Yamini, S.; Kumar, G. A.; Senthilselvan, J.

2018-01-01

A new reverse microemulsion system is proposed for the first time to synthesize NaYF4:Yb,Er nanocrystals, which demonstrated high upconversion emission in 550 and 662 nm at 980 nm diode laser excitation. The reverse microemulsion (μEs) system is comprised of CTAB and oleic acid as surfactant and 1-butanol co-surfactant and isooctane oil phase. The surfactant to water ratio is able to tune the microemulsion droplet size from 14 to 220 nm, which eventually controls the crystallinity and particulate morphology of NaYF4:Yb,Er. Also, the microemulsion precursor and calcination temperature plays certain role in transforming the cubic NaYF4:Yb,Er to highly luminescent hexagonal crystal structured upconversion material. Single phase hexagonal NaYF4:YbEr nanorod prepared by water-in-oil reverse microemulsion (μEs) gives intense red upconversion emission. Both nanosphere and nanorod shaped NaYF4:Yb,Er was obtained, but nanorod morphology resulted an enhanced upconversion luminescence. The structural, morphological, thermal and optical luminescence properties of the NaYF4:Yb,Er nanoparticles are discussed in detail by employing powder X-ray diffraction, dynamic light scattering, high resolution electron microscopy, TGA-DTA, UV-DRS, FTIR and photoluminescence spectroscopy. Intense upconversion emission achieved in the microemulsion synthesized NaYF4:Yb3+,Er3+ nanocrystal can make it as useful optical phosphor for solar cell applications.

Magnetic nanosensor particles in luminescence upconversion capability.

PubMed

Wilhelm, Stefan; Hirsch, Thomas; Scheucher, Elisabeth; Mayr, Torsten; Wolfbeis, Otto S

2011-09-05

Nanoparticles (NPs) exhibit interesting size-dependent electrical, optical, magnetic, and chemical properties that cannot be observed in their bulk counterparts. The synthesis of NPs (i.e., crystalline particles ranging in size from 1 to 100 nm) has been intensely studied in the past decades. Magnetic nanoparticles (MNPs) form a particularly attractive class of NPs and have found numerous applications such as in magnetic resonance imaging to visualize cancer, cardiovascular, neurological and other diseases. Other uses include drug targeting, tissue imaging, magnetic immobilization, hyperthermia, and magnetic resonance imaging. MNPs, due to their magnetic properties, can be easily separated from (often complex) matrices and manipulated by applying external magnetic field. Near-infrared to visible upconversion luminescent nanoparticles (UCLNPs) form another type of unusual nanoparticles. They are capable of emitting visible light upon NIR light excitation. Lanthanide-doped (Yb, Er) hexagonal NaYF₄ UCLNPs are the most efficient upconversion phosphors known up to now. The use of UCLNPs for in vitro imaging of cancer cells and in vivo imaging in tissues has been demonstrated. UCLNPs show great potential as a new class of luminophores for biological, biomedical, and sensor applications. We are reporting here on our first results on the combination of MNP and UCLNP technology within an ongoing project supported by the DFG and the FWF (Austria).

Temperature sensing of adipose tissue heating with the luminescent upconversion nanoparticles as nanothermometer: in vitro study

NASA Astrophysics Data System (ADS)

Yanina, I. Yu.; Volkova, E. K.; Zaharevich, A. M.; Konyukhova, J. G.; Kochubey, V. I.; Tuchin, V. V.

2017-03-01

The luminescence spectra of upconversion nanoparticles (UCNPs) imbedded in fat tissue were measured in a wide temperature range, from room to human body and further to hyperthermic temperatures. The two types of synthesized UCNP [NaYF4:Yb3+, Er3+] specimens, namely, powdered as-is and embedded into polymer film, were used. The results show that the luminescence of UCNPs placed under the adipose tissue layer is reasonably good sensitive to temperature change and reflects phase transitions of lipids in tissue cells. The most likely, multiple phase transitions are associated with the different components of fat cells such as phospholipids of cell membrane and lipids of fat droplets. In the course of fat cell heating, lipids of fat droplet first transit from a crystalline form to a liquid crystal form and then to a liquid form, which is characterized by much less scattering. The phase transitions of lipids were observed as the changes of the slope of the temperature dependence of UCNP luminescence intensity. The obtained results confirm a high sensitivity of the luminescent UCNPs to the temperature variations within tissues and show a strong potential for providing a controllable tissue thermolysis.

Delivery and reveal of localization of upconversion luminescent microparticles and quantum dots in the skin in vivo by fractional laser microablation, multimodal imaging, and optical clearing.

PubMed

Volkova, Elena K; Yanina, Irina Yu; Genina, Elina A; Bashkatov, Alexey N; Konyukhova, Julia G; Popov, Alexey P; Speranskaya, Elena S; Bucharskaya, Alla B; Navolokin, Nikita A; Goryacheva, Irina Yu; Kochubey, Vyacheslav I; Sukhorukov, Gleb B; Meglinski, Igor V; Tuchin, Valery V

2018-02-01

Delivery and spatial localization of upconversion luminescent microparticles [Y2O3:Yb, Er] (mean size ∼1.6  μm) and quantum dots (QDs) (CuInS2/ZnS nanoparticles coated with polyethylene glycol-based amphiphilic polymer, mean size ∼20  nm) inside rat skin was studied in vivo using a multimodal optical imaging approach. The particles were embedded into the skin dermis to the depth from 300 to 500  μm through microchannels performed by fractional laser microablation. Low-frequency ultrasound was applied to enhance penetration of the particles into the skin. Visualization of the particles was revealed using a combination of luminescent spectroscopy, optical coherence tomography, confocal microscopy, and histochemical analysis. Optical clearing was used to enhance the image contrast of the luminescent signal from the particles. It was demonstrated that the penetration depth of particles depends on their size, resulting in a different detection time interval (days) of the luminescent signal from microparticles and QDs inside the rat skin in vivo. We show that luminescent signal from the upconversion microparticles and QDs was detected after the particle delivery into the rat skin in vivo during eighth and fourth days, respectively. We hypothesize that the upconversion microparticles have created a long-time depot localized in the laser-created channels, as the QDs spread over the surrounding tissues. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Size-tunable and monodisperse Tm³⁺/Gd³⁺-doped hexagonal NaYbF₄ nanoparticles with engineered efficient near infrared-to-near infrared upconversion for in vivo imaging.

PubMed

Damasco, Jossana A; Chen, Guanying; Shao, Wei; Ågren, Hans; Huang, Haoyuan; Song, Wentao; Lovell, Jonathan F; Prasad, Paras N

2014-08-27

Hexagonal NaYbF4:Tm(3+) upconversion nanoparticles hold promise for use in high contrast near-infrared-to-near-infrared (NIR-to-NIR) in vitro and in vivo bioimaging. However, significant hurdles remain in their preparation and control of their morphology and size, as well as in enhancement of their upconversion efficiency. Here, we describe a systematic approach to produce highly controlled hexagonal NaYbF4:Tm(3+) nanoparticles with superior upconversion. We found that doping appropriate concentrations of trivalent gadolinium (Gd(3+)) can convert NaYbF4:Tm(3+) 0.5% nanoparticles with cubic phase and irregular shape into highly monodisperse NaYbF4:Tm(3+) 0.5% nanoplates or nanospheres in a pure hexagonal-phase and of tunable size. The intensity and the lifetime of the upconverted NIR luminescence at 800 nm exhibit a direct dependence on the size distribution of the resulting nanoparticles, being ascribed to the varied surface-to-volume ratios determined by the different nanoparticle size. Epitaxial growth of a thin NaYF4 shell layer of ∼2 nm on the ∼22 nm core of hexagonal NaYbF4:Gd(3+) 30%/Tm(3+) 0.5% nanoparticles resulted in a dramatic 350 fold NIR upconversion efficiency enhancement, because of effective suppression of surface-related quenching mechanisms. In vivo NIR-to-NIR upconversion imaging was demonstrated using a dispersion of phospholipid-polyethylene glycol (DSPE-PEG)-coated core/shell nanoparticles in phosphate buffered saline.

Size-Tunable and Monodisperse Tm3+/Gd3+-Doped Hexagonal NaYbF4 Nanoparticles with Engineered Efficient Near Infrared-to-Near Infrared Upconversion for In Vivo Imaging

PubMed Central

2015-01-01

Hexagonal NaYbF4:Tm3+ upconversion nanoparticles hold promise for use in high contrast near-infrared-to-near-infrared (NIR-to-NIR) in vitro and in vivo bioimaging. However, significant hurdles remain in their preparation and control of their morphology and size, as well as in enhancement of their upconversion efficiency. Here, we describe a systematic approach to produce highly controlled hexagonal NaYbF4:Tm3+ nanoparticles with superior upconversion. We found that doping appropriate concentrations of trivalent gadolinium (Gd3+) can convert NaYbF4:Tm3+ 0.5% nanoparticles with cubic phase and irregular shape into highly monodisperse NaYbF4:Tm3+ 0.5% nanoplates or nanospheres in a pure hexagonal-phase and of tunable size. The intensity and the lifetime of the upconverted NIR luminescence at 800 nm exhibit a direct dependence on the size distribution of the resulting nanoparticles, being ascribed to the varied surface-to-volume ratios determined by the different nanoparticle size. Epitaxial growth of a thin NaYF4 shell layer of ∼2 nm on the ∼22 nm core of hexagonal NaYbF4:Gd3+ 30%/Tm3+ 0.5% nanoparticles resulted in a dramatic 350 fold NIR upconversion efficiency enhancement, because of effective suppression of surface-related quenching mechanisms. In vivo NIR-to-NIR upconversion imaging was demonstrated using a dispersion of phospholipid-polyethylene glycol (DSPE-PEG)-coated core/shell nanoparticles in phosphate buffered saline. PMID:25027118

Dye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Xiang; Zhang, Yuanwei; Takle, Kendra

2016-01-26

Near Infrared (NIR) dye-sensitized upconversion nanoparticles (UCNPs) have recently been proposed in order to broaden the absorption range and to boost upconversion efficiency. However, implementing this strategy has been limited only to bare core UCNP structures that are faintly luminescent. Herein, we report on an approach to achieve significantly enhanced upconversion luminescence in dye-sensitized core-active shell UCNPs with a broadened absorption range via the doping of ytterbium ions in the UCNP shell in order to bridge the energy transfer from the dye to the UCNP core. As a result, we have been able to synergize the two most practical upconversionmore » booster effectors (dye-sensitizing and core/shell enhancement). The absolute quantum yield of our dye-sensitized core/active shell UCNPs at 800 nm was determined to be ~6% at 2 W/cm2, about 33 times larger than the highest value reported to date for existing 800 nm excitable UCNPs. Moreover, for the first time, by using dye-sensitized core/active shell UCNP embedded poly(methyl methacrylate) polymer implantable systems, we successfully shifted the optogenetic neuron excitation window to a wavelength that is compatible with deep tissue penetrable near the infrared wavelength at 800 nm. Finally, amphiphilic triblock copolymer, Pluronic F127 coatings permit the transfer of hydrophobic UCNPs into water, resulting in water-soluble nanoparticles with well-preserved optical property in aqueous solution. We believe that this research offers a new solution to enhance upconversion efficiency for photonic and biophotonic purposes and opens up new opportunities to use UCNPs as a NIR relay for optogenetic applications.« less

Amplified stimulated emission in upconversion nanoparticles for super-resolution nanoscopy

NASA Astrophysics Data System (ADS)

Liu, Yujia; Lu, Yiqing; Yang, Xusan; Zheng, Xianlin; Wen, Shihui; Wang, Fan; Vidal, Xavier; Zhao, Jiangbo; Liu, Deming; Zhou, Zhiguang; Ma, Chenshuo; Zhou, Jiajia; Piper, James A.; Xi, Peng; Jin, Dayong

2017-02-01

Lanthanide-doped glasses and crystals are attractive for laser applications because the metastable energy levels of the trivalent lanthanide ions facilitate the establishment of population inversion and amplified stimulated emission at relatively low pump power. At the nanometre scale, lanthanide-doped upconversion nanoparticles (UCNPs) can now be made with precisely controlled phase, dimension and doping level. When excited in the near-infrared, these UCNPs emit stable, bright visible luminescence at a variety of selectable wavelengths, with single-nanoparticle sensitivity, which makes them suitable for advanced luminescence microscopy applications. Here we show that UCNPs doped with high concentrations of thulium ions (Tm3+), excited at a wavelength of 980 nanometres, can readily establish a population inversion on their intermediate metastable 3H4 level: the reduced inter-emitter distance at high Tm3+ doping concentration leads to intense cross-relaxation, inducing a photon-avalanche-like effect that rapidly populates the metastable 3H4 level, resulting in population inversion relative to the 3H6 ground level within a single nanoparticle. As a result, illumination by a laser at 808 nanometres, matching the upconversion band of the 3H4 → 3H6 transition, can trigger amplified stimulated emission to discharge the 3H4 intermediate level, so that the upconversion pathway to generate blue luminescence can be optically inhibited. We harness these properties to realize low-power super-resolution stimulated emission depletion (STED) microscopy and achieve nanometre-scale optical resolution (nanoscopy), imaging single UCNPs; the resolution is 28 nanometres, that is, 1/36th of the wavelength. These engineered nanocrystals offer saturation intensity two orders of magnitude lower than those of fluorescent probes currently employed in stimulated emission depletion microscopy, suggesting a new way of alleviating the square-root law that typically limits the resolution that can be practically achieved by such techniques.

Biocompatible Er, Yb co-doped fluoroapatite upconversion nanoparticles for imaging applications

NASA Astrophysics Data System (ADS)

Anjana, R.; K. M., Kurias; M. K., Jayaraj

2017-08-01

Upconversion luminescence, visible emission on infra red (IR) excitation was achieved in a biocompatible material, fluoroapatite. Fluoroapatite crystals are well known biomaterials, which is a component of tooth enamel. Also it can be considered as an excellent host material for lanthanide doping since the ionic radii of lanthanide is similar to that of calcium ion(Ca2+) hence successful incorporation of dopants within the lattice is possible. Erbium (Er), Ytterbium (Yb) co-doped fluorapatite (FAp) nanoparticles were prepared by precipitation method. The particles show intense visible emission when excited with 980 nm laser. Since upconversion luminescence is a multiphoton process the excitation power dependence on emission will give number of photons involved in the emission of single photon. Excitation power dependence studies show that two photons are involved in the emission of single photons. The value of slope was different for different emission peak because of the difference in intermediate energy level involved. The crystal structure and morphology of the particle were determined using X-ray diffractometer (XRD) and field emission scanning electron microscope (FESEM). These particles with surface functionalisation can be used for live cell imaging.

Activation of the surface dark-layer to enhance upconversion in a thermal field

NASA Astrophysics Data System (ADS)

Zhou, Jiajia; Wen, Shihui; Liao, Jiayan; Clarke, Christian; Tawfik, Sherif Abdulkader; Ren, Wei; Mi, Chao; Wang, Fan; Jin, Dayong

2018-03-01

Thermal quenching, in which light emission experiences a loss with increasing temperature, broadly limits luminescent efficiency at higher temperature in optical materials, such as lighting phosphors1-3 and fluorescent probes4-6. Thermal quenching is commonly caused by the increased activity of phonons that leverages the non-radiative relaxation pathways. Here, we report a kind of heat-favourable phonons existing at the surface of lanthanide-doped upconversion nanomaterials to combat thermal quenching. It favours energy transfer from sensitizers to activators to pump up the intermediate excited-state upconversion process. We identify that the oxygen moiety chelating Yb3+ ions, [Yb...O], is the key underpinning this enhancement. We demonstrate an approximately 2,000-fold enhancement in blue emission for 9.7 nm Yb3+-Tm3+ co-doped nanoparticles at 453 K. This strategy not only provides a powerful solution to illuminate the dark layer of ultra-small upconversion nanoparticles, but also suggests a new pathway to build high-efficiency upconversion systems.

Experimental demonstration of plasmon enhanced energy transfer rate in NaYF4:Yb3+,Er3+ upconversion nanoparticles

PubMed Central

Lu, Dawei; Mao, Chenchen; Cho, Suehyun K.; Ahn, Sungmo; Park, Wounjhang

2016-01-01

Energy transfer upconversion (ETU) is known to be the most efficient frequency upconversion mechanism. Surface plasmon can further enhance the upconversion process, opening doors to many applications. However, ETU is a complex process involving competing transitions between multiple energy levels and it has been difficult to precisely determine the enhancement mechanisms. In this paper, we report a systematic study on the dynamics of the ETU process in NaYF4:Yb3+,Er3+ nanoparticles deposited on plasmonic nanograting structure. From the transient near-infrared photoluminescence under various excitation power densities, we observed faster energy transfer rates under stronger excitation conditions until it reached saturation where the highest internal upconversion efficiency was achieved. The experimental data were analyzed using the complete set of rate equations. The internal upconversion efficiency was found to be 56% and 36%, respectively, with and without the plasmonic nanograting. We also analyzed the transient green emission and found that it is determined by the infrared transition rate. To our knowledge, this is the first report of experimentally measured internal upconversion efficiency in plasmon enhanced upconversion material. Our work decouples the internal upconversion efficiency from the overall upconverted luminescence efficiency, allowing more targeted engineering for efficiency improvement. PMID:26739230

Fabrication and Luminescence Characterization of a Silica Nanomatrix Embedded with NaYF4:Yb:Er:Tm@NaGdF4/Fe3O4 Nanoparticles

NASA Astrophysics Data System (ADS)

Thangaraju, Dheivasigamani; Santhana, Vedi; Matsuda, Satoshi; Hayakawa, Yasuhiro

2018-05-01

Hexagonal NaYF4:Yb:Er:Tm@NaGdF4 core-shell nanocrystals were synthesized using a seed mediated hot injection method, and monodispersed Fe3O4 (4 nm) nanoparticles were prepared from iron(II) actylacetonate by a precursor thermal decomposition method. Structural and morphology verified NaYF4:Yb:Er:Tm@NaGdF4 and Fe3O4 nanoparticles were utilized for the preparation of NaYF4:Yb:Er:Tm@NaGdF4/Fe3O4@SiO2 nanocomposite using a micro-emulsion method. Existence of Fe3O4 in NaYF4:Yb:Er:Tm@NaGdF4 in SiO2 nano-spheres were confirmed with transmission electron microscopy. Luminescence measurement revealed that NaYF4:Yb:Er:Tm@NaGdF4 exhibited strong emissions at green and red regions, in addition to a weak blue emission also observed under 980 nm excitation. Up-conversion emission of the nanoparticle-embedded silica nanocomposite showed that the up-conversion emission was not affected by Fe3O4 nanoparticles.

A broadening temperature sensitivity range with a core-shell YbEr@YbNd double ratiometric optical nanothermometer

NASA Astrophysics Data System (ADS)

Marciniak, L.; Prorok, K.; Francés-Soriano, L.; Pérez-Prieto, J.; Bednarkiewicz, A.

2016-02-01

The chemical architecture of lanthanide doped core-shell up-converting nanoparticles can be engineered to purposely design the properties of luminescent nanomaterials, which are typically inaccessible to their homogeneous counterparts. Such an approach allowed to shift the up-conversion excitation wavelength from ~980 to the more relevant ~808 nm or enable Tb or Eu up-conversion emission, which was previously impossible to obtain or inefficient. Here, we address the issue of limited temperature sensitivity range of optical lanthanide based nano-thermometers. By covering Yb-Er co-doped core nanoparticles with the Yb-Nd co-doped shell, we have intentionally combined temperature dependent Er up-conversion together with temperature dependent Nd --> Yb energy transfer, and thus have expanded the temperature response range ΔT of a single nanoparticle based optical nano-thermometer under single ~808 nm wavelength photo-excitation from around ΔT = 150 K to over ΔT = 300 K (150-450 K). Such engineered nanocrystals are suitable for remote optical temperature measurements in technology and biotechnology at the sub-micron scale.The chemical architecture of lanthanide doped core-shell up-converting nanoparticles can be engineered to purposely design the properties of luminescent nanomaterials, which are typically inaccessible to their homogeneous counterparts. Such an approach allowed to shift the up-conversion excitation wavelength from ~980 to the more relevant ~808 nm or enable Tb or Eu up-conversion emission, which was previously impossible to obtain or inefficient. Here, we address the issue of limited temperature sensitivity range of optical lanthanide based nano-thermometers. By covering Yb-Er co-doped core nanoparticles with the Yb-Nd co-doped shell, we have intentionally combined temperature dependent Er up-conversion together with temperature dependent Nd --> Yb energy transfer, and thus have expanded the temperature response range ΔT of a single nanoparticle based optical nano-thermometer under single ~808 nm wavelength photo-excitation from around ΔT = 150 K to over ΔT = 300 K (150-450 K). Such engineered nanocrystals are suitable for remote optical temperature measurements in technology and biotechnology at the sub-micron scale. Electronic supplementary information (ESI) available: Characterization, structural and morphological characterization of nanocrystals, the measurement setup. See DOI: 10.1039/c5nr08223d

Mechanisms and concentrations dependence of up-conversion luminescence in Tm^3^+/Yb^3^+ codoped oxyfluoride glass-ceramics [rapid communication

NASA Astrophysics Data System (ADS)

Zhang, Junjie; He, Dongbing; Duan, Zhongchao; Zhang, Liyan; Dai, Shixun; Hu, Lili

2005-04-01

The up-conversion properties of Tm3+/Yb3+ codoped oxyfluoride glass-ceramics under 980 nm excitation were investigated. Intense blue up-conversion luminescence due to the Tm3+: 1G4 → 3H6 transition was observed in the glass-ceramics. The intensity of the blue up-conversion luminescence in a 1 mol% YbF3-containing glass-ceramic was found to be about 40 times stronger than that in the precursor oxyfluoride glass. The up-conversion mechanism is proposed. The reason for the intense Tm3+ up-conversion luminescence in the oxyfluoride glass-ceramics and the concentrations dependence of upconversion luminescence are also discussed.

Single-step synthesis of Er3+ and Yb3+ ions doped molybdate/Gd2O3 core-shell nanoparticles for biomedical imaging

NASA Astrophysics Data System (ADS)

Kamińska, Izabela; Elbaum, Danek; Sikora, Bożena; Kowalik, Przemysław; Mikulski, Jakub; Felcyn, Zofia; Samol, Piotr; Wojciechowski, Tomasz; Minikayev, Roman; Paszkowicz, Wojciech; Zaleszczyk, Wojciech; Szewczyk, Maciej; Konopka, Anna; Gruzeł, Grzegorz; Pawlyta, Mirosława; Donten, Mikołaj; Ciszak, Kamil; Zajdel, Karolina; Frontczak-Baniewicz, Małgorzata; Stępień, Piotr; Łapiński, Mariusz; Wilczyński, Grzegorz; Fronc, Krzysztof

2018-01-01

Nanostructures as color-tunable luminescent markers have become major, promising tools for bioimaging and biosensing. In this paper separated molybdate/Gd2O3 doped rare earth ions (erbium, Er3+ and ytterbium, Yb3+) core-shell nanoparticles (NPs), were fabricated by a one-step homogeneous precipitation process. Emission properties were studied by cathodo- and photoluminescence. Scanning electron and transmission electron microscopes were used to visualize and determine the size and shape of the NPs. Spherical NPs were obtained. Their core-shell structures were confirmed by x-ray diffraction and energy-dispersive x-ray spectroscopy measurements. We postulated that the molybdate rich core is formed due to high segregation coefficient of the Mo ion during the precipitation. The calcination process resulted in crystallization of δ/ξ (core/shell) NP doped Er and Yb ions, where δ—gadolinium molybdates and ξ—molybdates or gadolinium oxide. We confirmed two different upconversion mechanisms. In the presence of molybdenum ions, in the core of the NPs, Yb3+-{{{{MoO}}}4}2- (∣2F7/2, 3T2〉) dimers were formed. As a result of a two 980 nm photon absorption by the dimer, we observed enhanced green luminescence in the upconversion process. However, for the shell formed by the Gd2O3:Er, Yb NPs (without the Mo ions), the typical energy transfer upconversion takes place, which results in red luminescence. We demonstrated that the NPs were transported into cytosol of the HeLa and astrocytes cells by endocytosis. The core-shell NPs are sensitive sensors for the environment prevailing inside (shorter luminescence decay) and outside (longer luminescence decay) of the tested cells. The toxicity of the NPs was examined using MTT assay.

Structural and luminescent properties of a NaYF4-aerogel composite

NASA Astrophysics Data System (ADS)

Alattar, Ashraf M.; Drexler, Matthew; Twej, Wesam A. A.; Alamgir, Faisal M.

2018-07-01

Upconversion materials, capable of energy-shifting light, have direct application in devices where the tunability of the optical spectrum can result in higher performance. Due to the low transparency of upconversion nanomaterials, it is beneficial to disperse them in a medium with a low optical attenuation coefficient in order to allow light to reach and increase the contributions from each individual particle. Silica aerogels, with their high transparency and open porosity, are ideal media for the dispersion of the nanomaterials throughout a volume. NaYF4-based nanocrystals with differing dopants were incorporated into silica xerogels and aerogels to observe the effect of the composites on the properties of each. It was observed that, while the average surface area of the aerogel decreased in the composite, the shape and phase of the nanocrystals were preserved during xerogel processing. The luminescence of the nanoparticles increased upon incorporation into the xerogel composites. By accounting for effects emerging from collection geometry and the composite morphology, it is argued that the increase in the composite luminescent intensity is due to the nanoparticles being shielded from quenching effects by the silica matrix.

Ultrasensitive Detection of Ebola Virus Oligonucleotide Based on Upconversion Nanoprobe/Nanoporous Membrane System.

PubMed

Tsang, Ming-Kiu; Ye, WeiWei; Wang, Guojing; Li, Jingming; Yang, Mo; Hao, Jianhua

2016-01-26

Ebola outbreaks are currently of great concern, and therefore, development of effective diagnosis methods is urgently needed. The key for lethal virus detection is high sensitivity, since early-stage detection of virus may increase the probability of survival. Here, we propose a luminescence scheme of assay consisting of BaGdF5:Yb/Er upconversion nanoparticles (UCNPs) conjugated with oligonucleotide probe and gold nanoparticles (AuNPs) linked with target Ebola virus oligonucleotide. As a proof of concept, a homogeneous assay was fabricated and tested, yielding a detection limit at picomolar level. The luminescence resonance energy transfer is ascribed to the spectral overlapping of upconversion luminescence and the absorption characteristics of AuNPs. Moreover, we anchored the UCNPs and AuNPs on a nanoporous alumina (NAAO) membrane to form a heterogeneous assay. Importantly, the detection limit was greatly improved, exhibiting a remarkable value at the femtomolar level. The enhancement is attributed to the increased light-matter interaction throughout the nanopore walls of the NAAO membrane. The specificity test suggested that the nanoprobes were specific to Ebola virus oligonucleotides. The strategy combining UCNPs, AuNPs, and NAAO membrane provides new insight into low-cost, rapid, and ultrasensitive detection of different diseases. Furthermore, we explored the feasibility of clinical application by using inactivated Ebola virus samples. The detection results showed great potential of our heterogeneous design for practical application.

Upconversion luminescence nanosensor for TNT selective and label-free quantification in the mixture of nitroaromatic explosives.

PubMed

Ma, Yingxin; Wang, Leyu

2014-03-01

This paper reports a rapid, sensitive, and selective nanosensor for the detection of 2,4,6-trinitrotoluene (TNT) in the mixture aqueous solution of nitroaromatics independent of immunoassay or molecularly imprinted technology and complicated instruments. Despite many strategies including immunoassay and molecularly imprinted technologies been successfully developed for the detection of TNT, it is not easy to differentiate TNT from 2,4,6-trinitrophenol (TNP) due to their very similar chemical structures and properties. In this work, the amine functionalized NaYF4:Yb(3+)/Er(3+) upconversion luminescence nanoparticles (UCNPs) whose excitation (980 nm) and emission (543 nm) wavelength were far from the absorbance bands of other usual interference nitroaromatics including 2,4-dinitrotoluene (DNT), nitrobenzene (NB), and especially TNP, were utilized as the luminescent nanosensors for TNT luminescence detection. To make these UCNPs highly water stable and render the charge transfer from UCNPs to TNT easier, amino groups were introduced onto the surface of the UCNPs by coating a polymer layer of ethylene glycol dimethacrylate (EGDMA) hybridized with 3-aminopropyltriethoxysilane (APTS). After binding with TNT through amino groups on the UCNPs, the naked eye visible green upconversion luminescence of the UCNPs was dramatically quenched and thus a sensitive UC luminescence nanosensor was developed for TNT detection. However, other nitroaromatics including TNP, DNT, and NB have no influence on the green UC luminescence and thus no influence on the TNT detection. The luminescence intensity is negatively proportional to the concentration of TNT in the range of 0.01-9.0 µg/mL with the 3σ limit of detection (LOD) of 9.7 ng/mL. The present studies provide a novel and facile strategy to fabricate the upconversion luminescence sensors with highly selective recognition ability in aqueous media and are desirable for label free analysis of TNT in mixed solution independent of immunoassay and molecularly imprinted technology and complicated instruments. © 2013 Published by Elsevier B.V.

Application of upconversion luminescent-magnetic microbeads with weak background noise and facile separation in ochratoxin A detection

NASA Astrophysics Data System (ADS)

Liao, Zhenyu; Zhang, Ying; Su, Lin; Chang, Jin; Wang, Hanjie

2017-02-01

Ochratoxin A (OTA), the most harmful and abundant ochratoxin, is chemically stable and commonly existed in foodstuffs. In this work, upconversion luminescent-magnetic microbeads (UCLMMs) -based cytometric bead array for OTA detection with a less reagent consumption and high sensitivity has been established and optimized. In UCLMMs, upconversion nanocrystals (UCNs) for optical code present a weak background noise and no spectral cross talk between the encoding signals and target labels under two excitation conditions to improve detection sensitivity. While the superparamagnetic Fe3O4 nanoparticles (Fe3O4 NPs) aim for rapid analysis. The results show that the developed method has a sensitivity of 9.553 ppt below HPLC with a 50-μL sample and can be completed in <2 h with good accuracy and high reproducibility. Therefore, different colors of UCLMMs will become a promising assay platform for multiple mycotoxins after further improvement.

Energy-Cascaded Upconversion in an Organic Dye-Sensitized Core/Shell Fluoride Nanocrystal.

PubMed

Chen, Guanying; Damasco, Jossana; Qiu, Hailong; Shao, Wei; Ohulchanskyy, Tymish Y; Valiev, Rashid R; Wu, Xiang; Han, Gang; Wang, Yan; Yang, Chunhui; Ågren, Hans; Prasad, Paras N

2015-11-11

Lanthanide-doped upconversion nanoparticles hold promises for bioimaging, solar cells, and volumetric displays. However, their emission brightness and excitation wavelength range are limited by the weak and narrowband absorption of lanthanide ions. Here, we introduce a concept of multistep cascade energy transfer, from broadly infrared-harvesting organic dyes to sensitizer ions in the shell of an epitaxially designed core/shell inorganic nanostructure, with a sequential nonradiative energy transfer to upconverting ion pairs in the core. We show that this concept, when implemented in a core-shell architecture with suppressed surface-related luminescence quenching, yields multiphoton (three-, four-, and five-photon) upconversion quantum efficiency as high as 19% (upconversion energy conversion efficiency of 9.3%, upconversion quantum yield of 4.8%), which is about ~100 times higher than typically reported efficiency of upconversion at 800 nm in lanthanide-based nanostructures, along with a broad spectral range (over 150 nm) of infrared excitation and a large absorption cross-section of 1.47 × 10(-14) cm(2) per single nanoparticle. These features enable unprecedented three-photon upconversion (visible by naked eye as blue light) of an incoherent infrared light excitation with a power density comparable to that of solar irradiation at the Earth surface, having implications for broad applications of these organic-inorganic core/shell nanostructures with energy-cascaded upconversion.

The upconversion luminescence and magnetism in Yb3+/Ho3+ co-doped LaF3 nanocrystals for potential bimodal imaging

NASA Astrophysics Data System (ADS)

Syamchand, Sasidharanpillai S.; George, Sony

2016-12-01

Biocompatible upconversion nanoparticles with multifunctional properties can serve as potential nanoprobes for multimodal imaging. Herein, we report an upconversion nanocrystal based on lanthanum fluoride which is developed to address the imaging modalities, upconversion luminescence imaging and magnetic resonance imaging (MRI). Lanthanide ions (Yb3+ and Ho3+) doped LaF3 nanocrystals (LaF3 Yb3+/Ho3+) are fabricated through a rapid microwave-assisted synthesis. The hexagonal phase LaF3 nanocrystals exhibit nearly spherical morphology with average diameter of 9.8 nm. The inductively coupled plasma mass spectrometry (ICP-MS) analysis estimated the doping concentration of Yb3+ and Ho3+ as 3.99 and 0.41%, respectively. The nanocrystals show upconversion luminescence when irradiated with near-infrared (NIR) photons of wavelength 980 nm. The emission spectrum consists of bands centred at 542, 645 and 658 nm. The stronger green emission at 542 nm and the weak red emissions at 645 and 658 nm are assigned to 5S2 → 5I8 and 5F5 → 5I8 transitions of Ho3+, respectively. The pump power dependence of luminescence intensity confirmed the two-photon upconversion process. The nanocrystals exhibit paramagnetism due to the presence of lanthanide ion dopant Ho3+ and the magnetization is 19.81 emu/g at room temperature. The nanocrystals exhibit a longitudinal relaxivity ( r 1) of 0.12 s-1 mM-1 and transverse relaxivity ( r 2) of 28.18 s-1 mM-1, which makes the system suitable for developing T2 MRI contrast agents based on holmium. The LaF3 Yb3+/Ho3+ nanocrystals are surface modified by PEGylation to improve biocompatibility and enhance further functionalisation. The PEGylated nanocrystals are found to be non-toxic up to 50 μg/mL for 48 h of incubation, which is confirmed by the MTT assay as well as morphological studies in HeLa cells. The upconversion luminescence and magnetism together with biocompatibility enables the adaptability of the present system as a nanoprobe for potential bimodal imaging.

Fabrication of a LRET-based upconverting hybrid nanocomposite for turn-on sensing of H2O2 and glucose

NASA Astrophysics Data System (ADS)

Wu, Shuang; Kong, Xiang-Juan; Cen, Yao; Yuan, Jing; Yu, Ru-Qin; Chu, Xia

2016-04-01

Blood glucose detecting has aroused considerable attention because diabetes mellitus has become a worldwide publish health problem. Herein, we construct an exceptionally simple upconverting hybrid nanocomposite, composed of DNA-templated Ag nanoparticles (DNA-AgNPs) and NaYF4:Yb/Tm@NaYF4 core-shell upconversion nanoparticles (UCNPs), for the sensing of H2O2 and glucose. In this design, UCNPs with bared surface act as the donor, and DNA-AgNPs serve as efficient quenchers. DNA-AgNPs can be directly assembled on the bared surface of UCNPs, which further decreases the distance of donor-to-acceptor. The formation of DNA-AgNPs/UCNP nanocomposite results in luminescence quenching of UCNP by DNA-AgNPs through luminescence resonance energy transfer (LRET). Upon H2O2 addition, AgNPs can be etched and transformed into Ag+, leading to inhibition of the LRET process and causing the recovery of upconversion luminescence. Based on the conversion of glucose into H2O2 by glucose oxidase, the DNA-AgNPs/UCNP nanocomposite can also be exploited for glucose sensing. Moreover, due to the non-autofluorescence offered by UCNPs, the approach developed can be applied to monitor glucose levels in human serum samples with satisfactory results.Blood glucose detecting has aroused considerable attention because diabetes mellitus has become a worldwide publish health problem. Herein, we construct an exceptionally simple upconverting hybrid nanocomposite, composed of DNA-templated Ag nanoparticles (DNA-AgNPs) and NaYF4:Yb/Tm@NaYF4 core-shell upconversion nanoparticles (UCNPs), for the sensing of H2O2 and glucose. In this design, UCNPs with bared surface act as the donor, and DNA-AgNPs serve as efficient quenchers. DNA-AgNPs can be directly assembled on the bared surface of UCNPs, which further decreases the distance of donor-to-acceptor. The formation of DNA-AgNPs/UCNP nanocomposite results in luminescence quenching of UCNP by DNA-AgNPs through luminescence resonance energy transfer (LRET). Upon H2O2 addition, AgNPs can be etched and transformed into Ag+, leading to inhibition of the LRET process and causing the recovery of upconversion luminescence. Based on the conversion of glucose into H2O2 by glucose oxidase, the DNA-AgNPs/UCNP nanocomposite can also be exploited for glucose sensing. Moreover, due to the non-autofluorescence offered by UCNPs, the approach developed can be applied to monitor glucose levels in human serum samples with satisfactory results. Electronic supplementary information (ESI) available: Experimental details and supplementary figures. See DOI: 10.1039/c6nr00470a

Sub-10 nm lanthanide doped BaLuF{sub 5} nanocrystals: Shape controllable synthesis, tunable multicolor emission and enhanced near-infrared upconversion luminescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, Ling; Lu, Wei; Wang, Haibo

2015-04-15

Highlights: • Sub-10 nm cubic phase BaLuF{sub 5} nanocrystals were synthesized by a hydrothermal method for the first time. • Tunable multicolor from yellow to yellow-green was achieved by controlling Gd{sup 3+} content in BaLuF{sub 5}:Yb/Er system. • Intense near-infrared upconversion luminescence in BaLuF{sub 5}:Gd/Yb/Tm nanocrystal. • The enhancement near-infrared luminescence can be realized by adjusting the content of Gd{sup 3+} in BaLuF{sub 5}:Gd/Yb/Tm system. - Abstract: In this study, sub-10 nm BaLuF{sub 5} nanocrystals with cubic phase structure were synthesized by a solvothermal method using oleic acid as the stabilizing agent. The as-prepared BaLuF{sub 5} nanocrystals were characterized bymore » transmission electron microscopy (TEM), X-ray diffraction (XRD), and analyzed by the upconversion (UC) spectra. The TEM results reveal that these samples present high uniformity. Compared with Gd-free samples, the size of BaLuF{sub 5}:Yb/Er doped with 10% Gd{sup 3+} decreased to 5.6 nm. In addition, BaLuF{sub 5}:Yb/Tm/Gd upconversion nanoparticles (UCNPs) presented efficient near-infrared (NIR)-NIR UC luminescence. Therefore, it is expected that these ultra-small BaLuF{sub 5} nanocrystals with well-controlled shape, size, and UC emission have potential applications in biomedical imaging fields.« less

Up-conversion luminescence of Er3+ ions in lead-free germanate glasses under 800 nm and 980 nm cw diode laser excitation

NASA Astrophysics Data System (ADS)

Janek, J.; Lisiecki, R.; Ryba-Romanowski, W.; Pisarska, J.; Pisarski, W. A.

2017-12-01

Up-conversion luminescence spectra of Er3+ ions in multicomponent oxyfluoride glasses GeO2 - BaO - BaF2 - Ga2O3 - Er2O3 were examined. It was found that the up-conversion luminescence spectra of Er3+ are dependent on pumping wavelengths. The spectra recorded upon the excitation at 800 nm contained an intense green up-conversion luminescence corresponding to the 2H11/2,4S3/2 → 4I15/2 transitions and a very weak red luminescence related to the 4F9/2 - 4I15/2 transition. In spectra recorded upon 980 nm excitation the contribution of the red luminescence was markedly higher. The interaction mechanisms involved in up-conversion processes are proposed and observed dependence of intensity of up-converted luminescence on excitation power is discussed. The experimental results suggest that Er3+ singly doped lead-free oxyfluoride germanate glass is useful for up-conversion luminescence applications.

Luminescent and transparent nanopaper based on rare-earth up-converting nanoparticle grafted nanofibrillated cellulose derived from garlic skin.

PubMed

Zhao, Jingpeng; Wei, Zuwu; Feng, Xin; Miao, Miao; Sun, Lining; Cao, Shaomei; Shi, Liyi; Fang, Jianhui

2014-09-10

Highly flexible, transparent, and luminescent nanofibrillated cellulose (NFC) nanopaper with heterogeneous network, functionalized by rare-earth up-converting luminescent nanoparticles (UCNPs), was rapidly synthesized by using a moderate pressure extrusion paper-making process. NFC was successfully prepared from garlic skin using an efficient extraction approach combined with high frequency ultrasonication and high pressure homogenization after removing the noncellulosic components. An efficient epoxidation treatment was carried out to enhance the activity of the UCNPs (NaYF4:Yb,Er) with oleic acid ligand capped on the surface. The UCNPs after epoxidation then reacted with NFC in aqueous medium to form UCNP-grafted NFC nanocomposite (NFC-UCNP) suspensions at ambient temperature. Through the paper-making process, the assembled fluorescent NFC-UCNP hybrid nanopaper exhibits excellent properties, including high transparency, strong up-conversion luminescence, and good flexibility. The obtained hybrid nanopaper was characterized by transmission electron microscopy (TEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscope (FE-SEM), up-conversion luminescence (UCL) spectrum, and ultraviolet and visible (UV-vis) spectrophotometer. The experimental results demonstrate that the UCNPs have been successfully grafted to the NFC matrix with heterogeneous network. And the superiorly optical transparent and luminescent properties of the nanopaper mainly depend on the ratio of UCNPs to NFC. Of importance here is that, NFC and UCNPs afford the nanopaper a prospective candidate for multimodal anti-counterfeiting, sensors, and ion probes applications.

Fabrication and characterization of biological tissue phantoms with embedded nanoparticles

NASA Astrophysics Data System (ADS)

Skaptsov, A. A.; Ustalkov, S. O.; Mohammed, A. H. M.; Savenko, O. A.; Novikova, A. S.; Kozlova, E. A.; Kochubey, V. I.

2017-11-01

Phantoms are imitations of biological tissue, which are used for modelling of the light propagation in biological tissues. Carrying out any biophysical experiments requires an indispensable constancy of the initial experiment conditions. The use of solid undegradable phantoms is the basis to obtain reliable reproducible experimental results. The fabrication of biological tissues phantoms containing high absorbance or fluorescence nanoparticles and corresponding to specific mechanical, optical properties is an actual task. This work describes development, fabrication and characterization of such solid tissue phantoms with embedded CdSe/ZnS quantum dots, gold and upconversion nanoparticles. Luminescence of samples with CdSe/ZnS quantum dots and upconversion nanoparticles were recorded. A sample of gold nanorods was analyzed using thermal gravimetric analysis. It can be concluded that the samples are well suited for experiments on laser thermolysis.

Lanthanide-Doped KLu2F7 Nanoparticles with High Upconversion Luminescence Performance: A Comparative Study by Judd-Ofelt Analysis and Energy Transfer Mechanistic Investigation

NASA Astrophysics Data System (ADS)

Xu, Dekang; Li, Anming; Yao, Lu; Lin, Hao; Yang, Shenghong; Zhang, Yueli

2017-02-01

The development, design and the performance evaluation of rare-earth doped host materials is important for further optical investigation and industrial applications. Herein, we successfully fabricate KLu2F7 upconversion nanoparticles (UCNPs) through hydrothermal synthesis by controlling the fluorine-to-lanthanide-ion molar ratio. The structural and morphological results show that the samples are orthorhombic-phase hexagonal-prisms UCNPs, with average side length of 80 nm and average thickness of 110 nm. The reaction time dependent crystal growth experiment suggests that the phase transformation is a thermo-dynamical process and the increasing F-/Ln3+ ratio favors the formation of the thermo-dynamical stable phase - orthorhombic KLu2F7 structure. The upconversion luminescence (UCL) spectra display that the orthorhombic KLu2F7:Yb/Er UCNPs present stronger UCL as much as 280-fold than their cubic counterparts. The UCNPS also display better UCL performance compared with the popular hexagonal-phase NaREF4 (RE = Y, Gd). Our mechanistic investigation, including Judd-Ofelt analysis and time decay behaviors, suggests that the lanthanide tetrad clusters structure at sublattice level accounts for the saturated luminescence and highly efficient UCL in KLu2F7:Yb/Er UCNPs. Our research demonstrates that the orthorhombic KLu2F7 is a promising host material for UCL and can find potential applications in lasing, photovoltaics and biolabeling techniques.

Multifunctional nanoparticles for upconversion luminescence/MR multimodal imaging and magnetically targeted photothermal therapy.

PubMed

Cheng, Liang; Yang, Kai; Li, Yonggang; Zeng, Xiao; Shao, Mingwang; Lee, Shuit-Tong; Liu, Zhuang

2012-03-01

Theranostics, the combination of diagnostics and therapies, has become a new concept in the battles with various major diseases such as cancer. Herein, we develop multifunctional nanoparticles (MFNPs) with highly integrated functionalities including upconversion luminescence, superparamagnetism, and strong optical absorption in the near-infrared (NIR) region with high photostability. In vivo dual modal optical/magnetic resonance imaging of mice uncovers that by placing a magnet nearby the tumor, MFNPs tend to migrate toward the tumor after intravenous injection and show high tumor accumulation, which is ~8 folds higher than that without magnetic targeting. NIR laser irradiation is then applied to the tumors grown on MFNP-injected mice under magnetic tumor-targeting, obtaining an outstanding photothermal therapeutic efficacy with 100% of tumor elimination in a murine breast cancer model. We present here a strategy for multimodal imaging-guided, magnetically targeted physical cancer therapy and highlight the promise of using multifunctional nanostructures for cancer theranostics. Copyright © 2011 Elsevier Ltd. All rights reserved.

Spiny Nanorod and Upconversion Nanoparticle Satellite Assemblies for Ultrasensitive Detection of Messenger RNA in Living Cells.

PubMed

Gao, Rui; Hao, Changlong; Xu, Liguang; Xu, Chuanlai; Kuang, Hua

2018-04-17

Quantitation and in situ monitoring of target mRNA (mRNA) in living cells remains a significant challenge for the chemical and biomedical communities. To quantitatively detect mRNA expression levels in living cells, we have developed DNA-driven gold nanorod coated platinum-upconversion nanoparticle satellite assemblies (termed Au NR@Pt-UCNP satellites) for intracellular thymidine kinase 1 (TK1) mRNA analysis. The nanostructures were capable of recognizing target mRNA in a sequence-specific manner as luminescence of UCNPs was effectively quenched by Au NR@Pt within the assemblies. Following recognition, UCNPs detached from Au NR@Pt, resulting in luminescence restoration to achieve effective in situ imaging and quantifiable detection of target mRNA. The upconversional luminescence intensity of confocal images showed a good linear relationship with intracellular TK1 mRNA ranging from 1.17 to 65.21 fmol/10 μg RNA and a limit of detection (LOD) of 0.67 fmol/10 μg RNA. We believe that our present assay can be broadly applied for detection of endogenous biomolecules at the cellular and tissue levels and restoration of tissue homeostasis in vivo.

Alleviating Luminescence Concentration Quenching in Upconversion Nanoparticles through Organic Dye Sensitization.

PubMed

Wei, Wei; Chen, Guanying; Baev, Alexander; He, Guang S; Shao, Wei; Damasco, Jossana; Prasad, Paras N

2016-11-23

The phenomenon of luminescence concentration quenching exists widely in lanthanide-based luminescent materials, setting a limit on the content of lanthanide emitter that can be used to hold the brightness. Here, we introduce a concept involving energy harvesting by a strong absorber and subsequent energy transfer to a lanthanide that largely alleviates concentration quenching. We apply this concept to Nd 3+ emitters, and we show both experimentally and theoretically that the optimal doping concentration of Nd 3+ in colloidal NaYF 4 :Nd upconverting nanoparticles is increased from 2 to 20 mol% when an energy harvestor organic dye (indocyanine green, ICG) is anchored onto the nanoparticle surface, resulting in ∼10 times upconversion brightness. Theoretical analysis indicated that a combination of efficient photon harvesting due to the large absorption cross section of ICG (∼30 000 times higher than that of Nd 3+ ), non-radiative energy transfer (efficiency ∼57%) from ICG to the surface bound Nd 3+ ions, and energy migration among the Nd 3+ ions was able to activate Nd 3+ ions inside the nanoparticle at a rate comparable with that of the pronounced short-range quenching interaction at elevated Nd 3+ concentrations. This resulted in the optimal concentration increase to produce significantly enhanced brightness. Theoretical modeling shows a good agreement with the experimental observation. This strategy can be utilized for a wide range of other lanthanide-doped nanomaterials being utilized for bioimaging and solar cell applications.

Cooperative infrared to visible upconversion and visible to near-infrared quantum cutting in Tb and Yb co-doped glass containing Ag nanoparticles

NASA Astrophysics Data System (ADS)

Pan, Z.; Sekar, G.; Akrobetu, R.; Mu, R.; Morgan, S. H.

2011-10-01

Tb, Yb, and Ag co-doped glass nano-composites were synthesized in a lithium-lanthanum-aluminosilicate glass matrix (LLAS) by a melt-quench technique. Ag nanoparticles (NPs) were formed in the glass matrix and confirmed by optical absorption and transmission electron microscopy (TEM). Plasmon enhanced luminescence was observed. Cooperative infrared to visible upconversion and visible to near-infrared quantum cutting were studied for samples with different thermal annealing times. Because the Yb3+ emission at 940 - 1020 nm is matched well with the band gap of crystalline Si, the quantum cutting effect may have its potential application in silicon-based solar cells.

Tuning sputtered gold thickness to enhance absorption and emission in core-shell type erbium doped upconversion nanoparticles

NASA Astrophysics Data System (ADS)

Manurung, R. V.; Wu, C. T.; Chattopadhyay, S.

2018-03-01

Upconversion nanoparticles (UCNPs) converts near-infrared excitation to visible emission with advantages e.g. photostable, non-blinking, and background-free probes for bioimaging and biosensor. However, low quantum yield and low efficiency (∼1%) as drawback need to be enhanced. A plasmonic gold nano-structured surface was designed and fabricated to couple with the 980 nm radiation and produce plasmonic enhancement of the upconversion luminescence. The synthesis of the UCNPs was done by thermal decomposition and SiO2 coating prepared by the reverse microemulsion process. Here, we report a novel tunable plasmon-enhanced fluorescence by modulating the thickness and surface roughness of gold island film on Si. The localized surface plasmon resonance (LSPR) at 980 nm was obtained, matched with the native excitation of UCNPs resulting in maximum enhancement of 10-fold of green emission band at 540 nm for the Er-doped UCNPs.

Titanium mesh supported TiO2 nanowire arrays/upconversion luminescence Er3+-Yb3+ codoped TiO2 nanoparticles novel composites for flexible dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Liu, Wenwu; Zhang, Huanyu; Wang, Hui-gang; Zhang, Mei; Guo, Min

2017-11-01

Ti-mesh supported TiO2 nanowire arrays (NWAs)/upconversion luminescence Er3+-Yb3+ codoped TiO2 nanoparticles (UC-EY-TiO2 NPs) composite structured photoanodes for fully flexible dye sensitized solar cells (DSSCs) were firstly constructed via a hydrothermal and spin coating process. UV-vis-NIR absorption spectra of the TiO2 NWAs/UC-EY-TiO2 NPs composites exhibited strong absorption around near infrared (NIR) 980 nm. The composites excited by 980 nm NIR laser could emit upconversion fluorescence at 489, 526, 549 and 658 nm, which expanded the spectral response range and sunlight capturing capability of formed flexible DSSCs. Moreover, the TiO2 NWAs/UC-EY-TiO2 NPs was coated with an Nb2O5 thin layer to further suppress electron recombination losses. The complete flexible DSSCs based on Nb2O5 coated TiO2 NWAs/2.0 mol% Er3+-1.0 mol% Yb3+ codoped TiO2 NPs photoanode and Pt/ITO-PEN counter electrode exhibited an enhanced photon to current conversion efficiency of 8.10%, a 68% improvement compared to TiO2 NWAs/undoped TiO2 NPs based DSSCs (4.82%).

Synthesis and Characterization of Monodisperse Core-shell Lanthanide Upconversion Nanoparticles NaYF4: Yb,Tm/SiO2

NASA Astrophysics Data System (ADS)

Manurung, R. V.; Wiranto, G.; Hermida, I. D. P.

2018-05-01

Lanthanide up-converting luminescent nanoparticles (UCNPs) are exciting and promising materials for optical bioimaging, biosensor and theranostic due to their unique and advantageous optical and chemical properties. The UCNPs absorb low energy near-infrared (NIR) light and emit high-energy shorter wavelength photons (visible light). Their unique features allow them to overcome various problems associated with conventional imaging probes such as photostability, lack of toxicity, and to provide versatility for creating nanoplatforms with both imaging and therapeutic modalities. This paper reports synthesis and characterization of core-shell structured of NaYF4:Yb,Tm/SiO2 microspheres. The synthesis of lanthanide upconversion nanoparticles NaYF4:Yb,Tm was prepared by thermal decomposition process which involves dissolving organic precursors in high-boiling-point solvents oleic acid (OA) and octadecene (ODE). After that, the NaYF4:Yb,Tm phosphors was coated by silica via reverse microemulsion process to obtain core-shell structured NaYF4:Yb,Tm/SiO2. Scanning electron microscopy, transmission electron microscopy, specific area electron diffraction, and photoluminescence were applied to characterize these samples. The obtained core-shell structured NaYF4:Yb,Tm/SiO2 phosphors exhibit a perfect cubic morphology with narrow size distribution and smooth surface. Upon IR excitation at 980 nm, the NaYF4:Yb,Tm/SiO2 samples exhibit whitish blue upconversion (UC) luminescence, respectively. These phosphors show potential applications in the displaying on biological fields and biosensing.

Observing quantum control of up-conversion luminescence in Dy3+ ion doped glass from weak to intermediate shaped femtosecond laser fields

NASA Astrophysics Data System (ADS)

Liu, Pei; Cheng, Wenjing; Yao, Yunhua; Xu, Cheng; Zheng, Ye; Deng, Lianzhong; Jia, Tianqing; Qiu, Jianrong; Sun, Zhenrong; Zhang, Shian

2017-11-01

Controlling the up-conversion luminescence of rare-earth ions in real-time, in a dynamical and reversible manner, is very important for their application in laser sources, fiber-optic communications, light-emitting diodes, color displays and biological systems. In previous studies, the up-conversion luminescence control mainly focused on the weak femtosecond laser field. Here, we further extend this control behavior from weak to intermediate femtosecond laser fields. In this work, we experimentally and theoretically demonstrate that the up-conversion luminescence in Dy3+ ion doped glass can be artificially controlled by a π phase step modulation, but the up-conversion luminescence control behavior will be affected by the femtosecond laser intensity, and the up-conversion luminescence is suppressed by lower laser intensity while enhanced by higher laser intensity. We establish a new theoretical model (i.e. the fourth-order perturbation theory) to explain the physical control mechanism by considering the two- and four-photon absorption processes, and the theoretical results show that the relative weight of four-photon absorption in the whole excitation process will increase with the increase in laser intensity, and the interference between two- and four-photon absorptions results in up-conversion luminescence control modulation under different laser intensities. These theoretical and experimental works can provide a new method to control and understand up-conversion luminescence in rare-earth ions, and also may open a new opportunity to the related application areas of rare-earth ions.

Intense blue up-conversion luminescence in Tm 3+/Yb 3+ codoped oxyfluoride glass-ceramics containing β-PbF 2 nanocrystals

NASA Astrophysics Data System (ADS)

Zhang, Junjie; Duan, Zhongchao; He, Dongbing; Dai, Shixun; Zhang, Liyan; Hu, Lili

2005-12-01

Up-conversion luminescence properties of a Tm 3+/Yb 3+ codoped oxyfluoride glass-ceramics under 980 nm excitation are investigated. Intense blue emission centered at 476 nm, corresponding to 1G 4 → 3H 6 transitions of Tm 3+ was simultaneously observed in the transparent oxyfluoride glass ceramics at room temperature. The intensity of the blue up-conversion luminescence in a 1 mol% YbF 3-containing glass-ceramic was found to be about 40 times stronger than that in the precursor oxyfluoride glass. The reason for the intense Tm 3+ up-conversion luminescence in the oxyfluoride glass-ceramics is discussed. The dependence of up-conversion intensities on excitation power and possible up-conversion mechanism are also evaluated.

Intense blue up-conversion luminescence in Tm3+/Yb3+ codoped oxyfluoride glass-ceramics containing beta-PbF2 nanocrystals.

PubMed

Zhang, Junjie; Duan, Zhongchao; He, Dongbing; Dai, Shixun; Zhang, Liyan; Hu, Lili

2005-12-01

Up-conversion luminescence properties of a Tm3+/Yb3+ codoped oxyfluoride glass-ceramics under 980 nm excitation are investigated. Intense blue emission centered at 476 nm, corresponding to 1G4-->3H6 transitions of Tm3+ was simultaneously observed in the transparent oxyfluoride glass ceramics at room temperature. The intensity of the blue up-conversion luminescence in a 1 mol% YbF3-containing glass-ceramic was found to be about 40 times stronger than that in the precursor oxyfluoride glass. The reason for the intense Tm3+ up-conversion luminescence in the oxyfluoride glass-ceramics is discussed. The dependence of up-conversion intensities on excitation power and possible up-conversion mechanism are also evaluated.

Synthesis of Gd2O3:Ho3+/Yb3+ upconversion nanoparticles for latent fingermark detection on difficult surfaces

NASA Astrophysics Data System (ADS)

Kumar, A.; Tiwari, S. P.; Singh, A. K.; Kumar, K.

2016-07-01

Infrared to visible upconversion fluorescent nanoparticles of Gd2O3 codoped with Ho3+/Yb3+ ions are synthesized via thermal decomposition process. The X-ray diffraction analysis of as-synthesized nanoparticles and annealed sample at 1000 °C has shown body-centered cubic phase of Gd2O3. The synthesized phosphor has shown intense green emission upon 980-nm excitation. High-contrast latent fingermarks on some difficult semi-porous and non-porous surfaces under 980-nm diode laser excitation were developed through powder dusting and colloidal solution spraying techniques and the results are compared with the commercial green luminescent fingermark powder. The latent fingermarks were developed on transparent (biological glass slides), single-color (aluminum foil) and multicolor (plywood, plastic bottle and book cover page) background surfaces. The present study depicts that the upconversion-based latent fingermarks detection using Gd2O3:Ho3+/Yb3+ phosphor material is suitable over the other conventional powders and has potential for practical applications in forensic science.

In vivo multimodality imaging and cancer therapy by near-infrared light-triggered trans-platinum pro-drug-conjugated upconverison nanoparticles.

PubMed

Dai, Yunlu; Xiao, Haihua; Liu, Jianhua; Yuan, Qinghai; Ma, Ping'an; Yang, Dongmei; Li, Chunxia; Cheng, Ziyong; Hou, Zhiyao; Yang, Piaoping; Lin, Jun

2013-12-18

Controlling anticancer drug activity and release on demand is very significant in cancer therapy. The photoactivated platinum(IV) pro-drug is stable in the dark and can be activated by UV light. In this study, we develop a multifunctional drug delivery system combining upconversion luminescence/magnetic resonance/computer tomography trimodality imaging and NIR-activated platinum pro-drug delivery. We use the core-shell structured upconversion nanoparticles to convert the absorbed NIR light into UV to activate the trans-platinum(IV) pro-drug, trans,trans,trans-[Pt(N3)2(NH3)(py)(O2CCH2CH2COOH)2]. Compared with using the UV directly, the NIR has a higher tissue penetration depth and is less harmful to health. Meanwhile, the upconversion nanoparticles can effectively deliver the platinum(IV) pro-drugs into the cells by endocytosis. The mice treated with pro-drug-conjugated nanoparticles under near-infrared (NIR) irradiation demonstrated better inhibition of tumor growth than that under direct UV irradiation. This multifunctional nanocomposite could be used as multimodality bioimaging contrast agents and transducers by converting NIR light into UV for control of drug activity in practical cancer therapy.

Understanding the infrared to visible upconversion luminescence properties of Er{sup 3+}/Yb{sup 3+} co-doped BaMoO{sub 4} nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adhikari, Rajesh; Choi, Jinhyuk; Narro-García, R.

2014-08-15

In this paper we report the infrared to visible upconversion luminescence properties of Er{sup 3+}/Yb{sup 3+} co-doped BaMoO{sub 4} nanocrystals synthesized via microwave assisted sol–gel processing route. Structural, morphological and upconversion luminescence properties were investigated by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and Upconversion Photoluminescence spectra analysis. Results revealed that the oval shaped BaMoO{sub 4} nanocrystals ranging in size from 40 to 60 nm having tetragonal scheelite crystal structure were obtained by sol–gel route. The infrared to visible upconversion luminescence has been investigated in Er{sup 3+}/Yb{sup 3+} co-doped in BaMoO{sub 4}with different Yb{supmore » 3+} concentrations. Intense green upconversion emissions around 528, 550 nm, and red emission at 657 nm corresponding to the {sup 2}H{sub 11/2}, {sup 4}S{sub 3/2}, and {sup 4}F{sub 9/2} transitions, respectively to the {sup 4}I{sub 15/2} ground state were observed when excited by CW laser radiation at 980 nm. The green emissions were greatly enhanced after the addition of sensitizer (Yb{sup 3+} ions). The effect of Yb{sup 3+} on the upconversion luminescence intensity was analyzed and explained in terms of the energy transfer process based. The reported work establishes the understanding of molybdates as an alternative host material for upconversion luminescence. - Graphical abstract: Infrared to visible upconversion luminescence of Er{sup 3+}/Yb{sup 3+} co-doped BaMoO{sub 4} nanocrystals. - Highlights: • Nanocrystals were synthesized by microwave assisted sol–gel processing route. • Strong green emissions were observed in Er{sup 3+}/Yb{sup 3+} co-doped BaMoO{sub 4} nanocrystals. • Provides an insight on Upconversion luminescence properties of oxides host materials.« less

Upconversion luminescent logic gates and turn-on sensing of glutathione based on two-photon excited quantum dots conjugated with dopamine.

PubMed

Gui, Rijun; Jin, Hui; Liu, Xifeng; Wang, Zonghua; Zhang, Feifei; Xia, Jianfei; Yang, Min; Bi, Sai

2014-12-07

Under the two-photon excitation, upconversion luminescent "INHIBIT" and "OR" logic gates of water-dispersed CdTe quantum dots (QDs) were constituted by conjugating the QDs with dopamine. This facilitated the development of a novel QDs-based upconversion luminescent probe for efficient turn-on sensing of glutathione.

Upconversion luminescence and blackbody radiation in tetragonal YSZ co-doped with Tm(3+) and Yb(3+).

PubMed

Soares, M R N; Ferro, M; Costa, F M; Monteiro, T

2015-12-21

Lanthanide doped inorganic nanoparticles with upconversion luminescence are of utmost importance for biomedical applications, solid state lighting and photovoltaics. In this work we studied the downshifted luminescence, upconversion luminescence (UCL) and blackbody radiation of tetragonal yttrium stabilized zirconia co-doped with Tm(3+) and Yb(3+) single crystals and nanoparticles produced by laser floating zone and laser ablation in liquids, respectively. The photoluminescence (PL) and PL excitation (PLE) were investigated at room temperature (RT). PL spectra exhibit the characteristic lines in UV, blue/green, red and NIR regions of the Tm(3+) (4f(12)) under resonant excitation into the high energy (2S+1)LJ multiplets. Under NIR excitation (980 nm), the samples placed in air display an intense NIR at ∼800 nm due to the (1)G4→(3)H5/(3)H4→(3)H6 transitions. Additionally, red, blue/green and ultraviolet UCL is observed arising from higher excited (1)G4 and (1)D2 multiplets. The power excitation dependence of the UCL intensity indicated that 2-3 low energy absorbed photons are involved in the UCL for low power levels, while for high powers, the identified saturation is dependent on the material size with a enhanced effect on the NPs. The temperature dependence of the UCL was investigated for single crystals and targets used in the ablation. An overall increase of the integrated intensity was found to occur between 12 K and the RT. The thermally activated process is described by activation energies of 10 meV and 30 meV for single crystals and targets, respectively. For the NPs, the UCL was found to be strongly sensitive to pressure conditions. Under vacuum conditions, instead of the narrow lines of the Tm(3+), a wide blackbody radiation was detected, responsible for the change in the emission colour from blue to orange. This phenomenon is totally reversible when the NPs are placed at ambient pressure. The UCL/blackbody radiation in the nanosized material exhibits non-contact pressure colour-based sensor characteristics. Moreover, tuning the color of the blackbody radiation in the nanoparticles by harvesting the low energy photons into the visible spectral region was found to be possible by adjusting the excitation power, paving the way for further developments of these nanoparticles for lighting and photovoltaic applications.

Chemical sensing and imaging based on photon upconverting nano- and microcrystals: a review

NASA Astrophysics Data System (ADS)

Christ, Simon; Schäferling, Michael

2015-09-01

The demand for photostable luminescent reporters that absorb and emit light in the red to near-infrared (NIR) spectral region continues in biomedical research and bioanalysis. In recent years, classical organic fluorophores have increasingly been displaced by luminescent nanoparticles. These consist of either polymer or silica based beads that are loaded with luminescent dyes, conjugated polymers, or inorganic nanomaterials such as semiconductor nanocrystals (quantum dots), colloidal clusters of silver and gold, or carbon dots. Among the inorganic materials, photon upconversion nanocrystals exhibit a high potential for application to bioimaging or biomolecular assays. They offer an exceptionally high photostability, can be excited in the NIR, and their anti-Stokes emission enables luminescence detection free of background and perturbing scatter effects even in complex biological samples. These lanthanide doped inorganic crystals have multiple emission lines that can be tuned by the selection of the dopants. This review article is focused on the applications of functionalized photon upconversion nanoparticles (UCNPs) to chemical sensing. This is a comparatively new field of research activity and mainly directed at the sensing and imaging of ubiquitous chemical analytes in biological samples, particularly in living cells. For this purpose, the particles have to be functionalized with suitable indicator dyes or recognition elements, as they do not show an intrinsic or specific luminescence response to most of these analytes (e.g. pH, oxygen, metal ions). We describe the strategies for the design of such responsive nanocomposites utilizing either luminescence resonance energy transfer or emission-reabsorption (inner filter effect) mechanisms and also highlight examples for their use either immobilized in sensor layers or directly as nanoprobes for intracellular sensing and imaging.

The role of Nb in intensity increase of Er ion upconversion luminescence in zirconia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smits, K., E-mail: smits@cfi.lu.lv; Sarakovskis, A.; Grigorjeva, L.

2014-06-07

It is found that Nb co-doping increases the luminescence and upconversion luminescence intensity in rare earth doped zirconia. Er and Yb-doped nanocrystalline samples with or without Nb co-doping were prepared by sol-gel method and thermally annealed to check for the impact of phase transition on luminescence properties. Phase composition and grain sizes were examined by X-ray diffraction; the morphology was checked by scanning- and high-resolution transmission electron microscopes. Both steady-state and time-resolved luminescence were studied. Comparison of samples with different oxygen vacancy concentrations and different Nb concentrations confirmed the known assumption that oxygen vacancies are the main agents for tetragonalmore » or cubic phase stabilization. The oxygen vacancies quench the upconversion luminescence; however, they also prevent agglomeration of rare-earth ions and/or displacement of rare-earth ions to grain surfaces. It is found that co-doping with Nb ions significantly (>20 times) increases upconversion luminescence intensity. Hence, ZrO{sub 2}:Er:Yb:Nb nanocrystals may show promise for upconversion applications.« less

Multicolor Upconversion Nanoprobes Based on a Dual Luminescence Resonance Energy Transfer Assay for Simultaneous Detection and Bioimaging of [Ca2+ ]i and pHi in Living Cells.

PubMed

Song, Xinyue; Yue, Zihong; Zhang, Jiayu; Jiang, Yanxialei; Wang, Zonghua; Zhang, Shusheng

2018-04-25

Intracellular [Ca 2+ ] i and pH i have a close relationship, and their abnormal levels can result in cell dysfunction and accompanying diseases. Thus, simultaneous determination of [Ca 2+ ] i and pH i can more accurately investigate complex biological processes in an integrated platform. Herein, multicolor upconversion nanoparticles (UCNPs) were prepared with the advantages of no spectral overlapping, single NIR excitation wavelengths, and greater tissue penetration depth. The upconversion nanoprobes were easily prepared by the attachment of two fluorescent dyes, Fluo-4 and SNARF-4F. Based on the dual luminescence resonance energy transfer (LRET) process, the blue and green fluorescence of the UCNPs were specially quenched and selectively recovered after the detachment and/or absorbance change of the attached fluorescent dyes, enabling dual detection. Importantly, the developed nanoprobe could successfully be applied for the detection of [Ca 2+ ] i and pH i change in adenosine triphosphate (ATP) and ethylene glycol tetraacetic acid (EGTA) stimulation in living cells. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Core-shell-shell heterostructures of α-NaLuF4:Yb/Er@NaLuF4:Yb@MF2 (M = Ca, Sr, Ba) with remarkably enhanced upconversion luminescence.

PubMed

Su, Yue; Liu, Xiuling; Lei, Pengpeng; Xu, Xia; Dong, Lile; Guo, Xianmin; Yan, Xingxu; Wang, Peng; Song, Shuyan; Feng, Jing; Zhang, Hongjie

2016-07-05

Core-shell-shell heterostructures of α-NaLuF4:Yb/Er@NaLuF4:Yb@MF2 (M = Ca, Sr, Ba) have been successfully fabricated via the thermal decomposition method. Upconversion nanoparticles (UCNPs) were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), upconversion luminescence (UCL) spectroscopy, etc. Under 980 nm excitation, the emission intensities of the UCNPs are remarkably enhanced after coating the MF2 (M = Ca, Sr, and Ba) shell. Among these samples, CaF2 coated UCNPs show the strongest overall emission, while BaF2 coated UCNPs exhibit the longest lifetime. These results demonstrate that alkaline earth metal fluorides are ideal materials to improve the UCL properties. Meanwhile, although the lattice mismatch between the ternary NaREF4 core and the binary MF2 (M = Sr and Ba) shell is relatively large, the successfully synthesized NaLuF4:Yb/Er@NaLuF4:Yb@MF2 indicates a new outlook on the fabrication of heterostructural core-shell UCNPs.

Color-coded multilayer photopatterned microstructures using lanthanide (III) ion co-doped NaYF4 nanoparticles with upconversion luminescence for possible applications in security.

PubMed

Kim, Won Jin; Nyk, Marcin; Prasad, Paras N

2009-05-06

We report a method for fabricating predefined photopatterns of upconversion nanophosphors using a chemical amplification reaction for direct writing of films with multilayer color-coded patterning for security applications. To photopattern the nanocrystal film we have synthesized rare-earth ion (Er(3+)/Yb(3+) or Tm(3+)/Yb(3+)) co-doped sodium yttrium fluoride (alpha-NaYF(4)) nanophosphors and functionalized the nanocrystal surfaces by incorporation of a photopatternable ligand such as t-butoxycarbonyl (t-BOC). The surface modification allows photopatterning of the nanophosphor solid state film. Furthermore, upconversion nanophosphors show a nearly quadratic dependence of the upconversion photoluminescence (PL) intensity on the excitation light power, and tailoring of the PL wavelength is possible by changing the lanthanide ions. We have demonstrated the capability of anchoring nanophosphors at desirable locations by a photolithography technique. The photopatterned films exhibit fixed nanophosphor structures clearly identifiable by strong upconversion photoluminescence under IR illumination which is useful for a number of applications in security.

Fabrication and evaluation of chitosan/NaYF4:Yb3+/Tm3+ upconversion nanoparticles composite beads based on the gelling of Pickering emulsion droplets.

PubMed

Yan, Huiqiong; Chen, Xiuqiong; Shi, Jia; Shi, Zaifeng; Sun, Wei; Lin, Qiang; Wang, Xianghui; Dai, Zihao

2017-02-01

The rare earth ion doped upconversion nanoparticles (UCNPs) synthesized by hydrophobic organic ligands possess poor solubility and low fluorescence quantum yield in aqueous media. To conquer this issue, NaYF 4 :Yb 3+ /Tm 3+ UCNPs, synthesized by a hydrothermal method, were coated with F127 and then assembled with chitosan to fabricate the chitosan/NaYF 4 :Yb 3+ /Tm 3+ composite beads (CS/NaYF 4 :Yb 3+ /Tm 3+ CBs) by Pickering emulsion system. The characterization results revealed that the as-synthesized NaYF 4 :Yb 3+ /Tm 3+ UCNPs with an average size of 20nm exhibited spherical morphology, high crystallinity and characteristic emission upconversion fluorescence with an overall blue color output. The NaYF 4 :Yb 3+ /Tm 3+ UCNPs were successfully conjugated on the surface of chitosan beads by the gelling of emulsion droplets. The resultant CS/NaYF 4 :Yb 3+ /Tm 3+ CBs showed good upconversion luminescent property, drug-loading capacity, release performance and excellent biocompatibility, exhibiting great potentials in targeted drug delivery and tissue engineering with potential tracking capability and lasting release performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis of upconversion nanoparticles conjugated with graphene oxide quantum dots and their use against cancer cell imaging and photodynamic therapy.

PubMed

Choi, Seung Yoo; Baek, Seung Hoon; Chang, Sung-Jin; Song, Yohan; Rafique, Rafia; Lee, Kang Taek; Park, Tae Jung

2017-07-15

Multifunctional nanocomposite has a huge potential for cell imaging, drug delivery, and improving therapeutic effect with less side effects. To date, diverse approaches have been demonstrated to endow a single nanostructure with multifunctionality. Herein, we report the synthesis and application of core-shell nanoparticles composed with upconversion nanoparticle (UCNP) as a core and a graphene oxide quantum dot (GOQD) as a shell. The UCNP was prepared and applied for imaging-guided analyses of upconversion luminescence. GOQD was prepared and employed as promising drug delivery vehicles to improve anti-tumor therapy effect in this study. Unique properties of UCNPs and GOQDs were incorporated into a single nanostructure to provide desirable functions for cell imaging and drug delivery. In addition, hypocrellin A (HA) was loaded on GOQDs for photo-dynamic therapy (PDT). HA, a commonly used chemotherapy drug and a photo-sensitizer, was conjugated with GOQD by π-π interaction and loaded on PEGylated UCNP without complicated synthetic process, which can break structure of HA. Applying these core-shell nanoparticles to MTT assay, we demonstrated that the UCNPs with GOQD shell loaded with HA could be excellent candidates as multifunctional agents for cell imaging, drug delivery and cell therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

Upconversion luminescence resonance energy transfer-based aptasensor for the sensitive detection of oxytetracycline.

PubMed

Zhang, Hui; Fang, Congcong; Wu, Shijia; Duan, Nuo; Wang, Zhouping

2015-11-15

In this work, a biosensor based on luminescence resonance energy transfer (LRET) from NaYF4:Yb,Tm upconversion nanoparticles (UCNPs) to SYBR Green I has been developed. The aptamers are covalently linked to UCNPs and hybridized with their complementary strands. The subsequent addition of SYBR Green allows SYBR Green I to insert into the formed double-stranded DNA (dsDNA) duplex and brings the energy donor and acceptor into close proximity, leading to the fluorescence of UCNPs transferred to SYBR Green I. When excited at 980 nm, the UCNPs emit luminescence at 477 nm, and this energy is transferred to SYBR Green I, which emits luminescence at 530 nm. In the presence of oxytetracycline (OTC), the aptamers prefer to bind to its corresponding analyte and dehybridize with the complementary DNA. This dehybridization leads to the liberation of SYBR Green I, which distances SYBR Green I from the UCNPs and recovers the UCNPs' luminescence. Under optimal conditions, a linear calibration is obtained between the ratio of I530 to I477 nm (I530/I477) and the OTC concentration, which ranges from 0.1 to 10 ng/ml with a limit of detection (LOD) of 0.054 ng/ml. Copyright © 2015 Elsevier Inc. All rights reserved.

Phytotoxicity, Translocation, and Biotransformation of NaYF₄ Upconversion Nanoparticles in a Soybean Plant.

PubMed

Yin, Wenyan; Zhou, Liangjun; Ma, Yuhui; Tian, Gan; Zhao, Jiating; Yan, Liang; Zheng, Xiaopeng; Zhang, Peng; Yu, Jie; Gu, Zhanjun; Zhao, Yuliang

2015-09-01

The increasing uses of rare-earth-doped upconversion nanoparticles (UCNPs) have obviously caused many concerns about their potential toxicology on live organisms. In addition, the UCNPs can be released into the environment, then transported into edible crop plants, and finally entered into food chain. Here, the soybean is chosen as a model plant to study the subchronic phytotoxicity, translocation, and biotransformation of NaYF4 UCNPs. The incubation with UCNPs at a relative low concentration of 10 μg mL(-1) leads to growth promotion for the roots and stems, while concentration exceeding 50 μg mL(-1) brings concentration-dependent inhibition. Upconversion luminescence imaging and scanning electron microscope characterization show that the UCNPs can be absorbed by roots and parts of the adsorbed UCNPs are then transported through vessels to stems and leaves. The near-edge X-ray absorption fine structure spectra reveal that the adsorbed NaYF4 nanoparticles are relatively stable during a 10 d incubation. Energy-dispersive X-ray spectrum further indicates that a small amount of NaYF4 is dissolved/digested and can transform into Y-phosphate clusters in roots. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Co-operative energy transfer in Yb3+-Er3+ co-doped SrGdxOy upconverting phosphor

NASA Astrophysics Data System (ADS)

Kumar, Ashwini; Pathak, Trilok K.; Dhoble, S. J.; . Terblans, J. J.; Swart, H. C.

2018-04-01

Upconversion nanoparticles (UCNPs) have shown considerable interest in many fields; however, low upconversion efficiency of UCNPs is still the most severe limitation of their applications. Yb3+ and Er3+ co-doped SrGd4O7/Gd2O3(SGO) upconversion (UC) phosphors were synthesized by a modified co-precipitation process. The UC properties were investigated by direct excitation with a 980 nm laser. It was observed that the as prepared materials showed relatively strong green emission, while upon the incorporation of the Er3+ ion, there was an increase in the upconversion luminescence intensity for the red component. The effect of different doping concentration of Er3+on the emission spectra and X-ray diffraction patterns of the UC materials have also been studied. The luminescence lifetimes and Commission Internationale de L'Eclairage coordinates for these as prepared samples were determined to understand the energy transfer (ET) mechanisms occurring between Yb3+ and Er3+ in the SGO host matrix. The UC luminescence intensity as a function of laser pump power was monitored and it was confirmed that the UC process in SGO:Yb3+/Er3+is a two-photon absorption process. The findings reported here are expected to provide a better approach for understanding of the ET mechanisms in the oxide based Yb3+/Er3+ co-doped UC phosphors. This study might be helpful in precisely defined applications where optical transitions are essential criterion and this can be easily achieved by smart tuning of the emission properties of Yb3+/Er3+ co-doped UC phosphors.

Spectral evidence for multi-pathway contribution to the upconversion pathway in NaYF4:Yb3+,Er3+ phosphors.

PubMed

Cho, Youngho; Song, Si Won; Lim, Soo Yeong; Kim, Jae Hun; Park, Chan Ryang; Kim, Hyung Min

2017-03-08

Although upconversion phosphors have been widely used in nanomedicine, laser engineering, bioimaging, and solar cell technology, the upconversion luminescence mechanism of the phosphors has been fiercely debated. A comprehensive understanding of upconversion photophysics has been significantly impeded because the number of photons incorporated in the process in different competitive pathways could not be resolved. Few convincing results to estimate the contribution of each of the two-, three-, and four-photon channels of near-infrared (NIR) energy have been reported in yielding upconverted visible luminescence. In this study, we present the energy upconversion process occurring in NaYF 4 :Yb 3+ ,Er 3+ phosphors as a function of excitation frequency and power density. We investigated the upconversion mechanism of lanthanide phosphors by comparing UV/VIS one-photon excitation spectra and NIR multi-photon spectra. A detailed analysis of minor transitions in one-photon spectra and luminescence decay enables us to assign electronic origins of individual bands in multi-photon upconversion luminescence and provides characteristic transitions representing the corresponding upconversion channel. Furthermore, we estimated the quantitative contribution of multiple channels with respect to irradiation power and excitation energy.

An Nd3+-sensitized upconversion nanophosphor modified with a cyanine dye for the ratiometric upconversion luminescence bioimaging of hypochlorite

NASA Astrophysics Data System (ADS)

Zou, Xianmei; Liu, Yi; Zhu, Xingjun; Chen, Min; Yao, Liming; Feng, Wei; Li, Fuyou

2015-02-01

Excessive or misplaced production of ClO- in living systems is usually associated with many human diseases. Therefore, it is of great importance to develop an effective and sensitive method to detect ClO- in living systems. Herein, we designed an 808 nm excited upconversion luminescence nanosystem, composed of the Nd3+-sensitized core-shell upconversion nanophosphor NaYF4:30%Yb,1%Nd,0.5%Er@NaYF4:20%Nd, which serves as an energy donor, and the ClO--responsive cyanine dye hCy3, which acts as an energy acceptor, for ratiometric upconversion luminescence (UCL) monitoring of ClO-. The detection limit of ClO- for this nanoprobe in aqueous solution is 27 ppb and the nanoprobe was successfully used to detect the ClO- in the living cells by ratiometric upconversion luminescence. Importantly, the nanoprobe realized the detection of ClO- in a mouse model of arthritis, which produced an excess of ROS, under 808 nm irradiation in vivo. The excitation laser efficiently reduced the heating effect, compared to the commonly used 980 nm laser for upconversion systems.Excessive or misplaced production of ClO- in living systems is usually associated with many human diseases. Therefore, it is of great importance to develop an effective and sensitive method to detect ClO- in living systems. Herein, we designed an 808 nm excited upconversion luminescence nanosystem, composed of the Nd3+-sensitized core-shell upconversion nanophosphor NaYF4:30%Yb,1%Nd,0.5%Er@NaYF4:20%Nd, which serves as an energy donor, and the ClO--responsive cyanine dye hCy3, which acts as an energy acceptor, for ratiometric upconversion luminescence (UCL) monitoring of ClO-. The detection limit of ClO- for this nanoprobe in aqueous solution is 27 ppb and the nanoprobe was successfully used to detect the ClO- in the living cells by ratiometric upconversion luminescence. Importantly, the nanoprobe realized the detection of ClO- in a mouse model of arthritis, which produced an excess of ROS, under 808 nm irradiation in vivo. The excitation laser efficiently reduced the heating effect, compared to the commonly used 980 nm laser for upconversion systems. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06407k

Accurate Quantitative Sensing of Intracellular pH based on Self-ratiometric Upconversion Luminescent Nanoprobe.

PubMed

Li, Cuixia; Zuo, Jing; Zhang, Li; Chang, Yulei; Zhang, Youlin; Tu, Langping; Liu, Xiaomin; Xue, Bin; Li, Qiqing; Zhao, Huiying; Zhang, Hong; Kong, Xianggui

2016-12-09

Accurate quantitation of intracellular pH (pH i ) is of great importance in revealing the cellular activities and early warning of diseases. A series of fluorescence-based nano-bioprobes composed of different nanoparticles or/and dye pairs have already been developed for pH i sensing. Till now, biological auto-fluorescence background upon UV-Vis excitation and severe photo-bleaching of dyes are the two main factors impeding the accurate quantitative detection of pH i . Herein, we have developed a self-ratiometric luminescence nanoprobe based on förster resonant energy transfer (FRET) for probing pH i , in which pH-sensitive fluorescein isothiocyanate (FITC) and upconversion nanoparticles (UCNPs) were served as energy acceptor and donor, respectively. Under 980 nm excitation, upconversion emission bands at 475 nm and 645 nm of NaYF 4 :Yb 3+ , Tm 3+ UCNPs were used as pH i response and self-ratiometric reference signal, respectively. This direct quantitative sensing approach has circumvented the traditional software-based subsequent processing of images which may lead to relatively large uncertainty of the results. Due to efficient FRET and fluorescence background free, a highly-sensitive and accurate sensing has been achieved, featured by 3.56 per unit change in pH i value 3.0-7.0 with deviation less than 0.43. This approach shall facilitate the researches in pH i related areas and development of the intracellular drug delivery systems.

Accurate Quantitative Sensing of Intracellular pH based on Self-ratiometric Upconversion Luminescent Nanoprobe

NASA Astrophysics Data System (ADS)

Li, Cuixia; Zuo, Jing; Zhang, Li; Chang, Yulei; Zhang, Youlin; Tu, Langping; Liu, Xiaomin; Xue, Bin; Li, Qiqing; Zhao, Huiying; Zhang, Hong; Kong, Xianggui

2016-12-01

Accurate quantitation of intracellular pH (pHi) is of great importance in revealing the cellular activities and early warning of diseases. A series of fluorescence-based nano-bioprobes composed of different nanoparticles or/and dye pairs have already been developed for pHi sensing. Till now, biological auto-fluorescence background upon UV-Vis excitation and severe photo-bleaching of dyes are the two main factors impeding the accurate quantitative detection of pHi. Herein, we have developed a self-ratiometric luminescence nanoprobe based on förster resonant energy transfer (FRET) for probing pHi, in which pH-sensitive fluorescein isothiocyanate (FITC) and upconversion nanoparticles (UCNPs) were served as energy acceptor and donor, respectively. Under 980 nm excitation, upconversion emission bands at 475 nm and 645 nm of NaYF4:Yb3+, Tm3+ UCNPs were used as pHi response and self-ratiometric reference signal, respectively. This direct quantitative sensing approach has circumvented the traditional software-based subsequent processing of images which may lead to relatively large uncertainty of the results. Due to efficient FRET and fluorescence background free, a highly-sensitive and accurate sensing has been achieved, featured by 3.56 per unit change in pHi value 3.0-7.0 with deviation less than 0.43. This approach shall facilitate the researches in pHi related areas and development of the intracellular drug delivery systems.

Strategies for the design of bright upconversion nanoparticles for bioanalytical applications

NASA Astrophysics Data System (ADS)

Wiesholler, Lisa M.; Hirsch, Thomas

2018-06-01

In recent years upconversion nanoparticles (UCNPs) received great attention because of their outstanding optical properties. Especially in bioanalytical applications this class of materials can overcome limitations of common probes like high background fluorescence or blinking. Nevertheless, the requirements for UCNPs to be applicable in biological samples, e.g. small size, water-dispersibility, excitation at low power density are in contradiction with the demand of high brightness. Therefore, a lot of attention is payed to the enhancement of the upconversion luminescence. This review discuss the recent trends and strategies to boost the brightness of UCNPs, classified in three main directions: a) improving the efficiency of energy absorption by the sensitizer via coupling to plasmonic or photonic structures or via attachment of ligands for light harvesting; b) minimizing non-radiative deactivation by variations in the architecture of UCNPs; and c) changing the excitation wavelength to get bright particles at low excitation power density for applications in aqueous systems. These strategies are critically reviewed including current limitations as well as future perspectives for the design of efficient UCNPs especially for sensing application in biological samples or cells.

[Up-conversion luminescent materials of Y2O3: RE(RE=Er or Er/Yb) prepared by sol-gel combustion synthesis].

PubMed

Han, Peng-de; Zhang, Le; Huang, Xiao-gu; Wang, Li-xi; Zhang, Qi-tu

2010-11-01

Y2O3 powders doped with rare-earth ions were synthesized by sol-gel combustion synthesis. Effects of different calcinating temperatures, Er+ doping concentration and Yb3+ doping concentration were investigated. It was shown that the single well crystallized Y2O3 powders could be obtained at 800 degrees C; as the calcinating temperature increased, the crystallinity and upconversion luminescence intensity were higher; the particle size was uniform around 1 microm at 900 degrees C; when Er3+ doping concentration was 1 mol%, the green upconversion luminescence intensity reached the maximum, but for red upconversion luminescence, when Er3+ doping concentration was 4 mol%, its luminescence intensity reached the maximum; as the ratio of Yb3+ to Er3+ was 4:1, the green emission intensity reached the maximum, while the red emission intensity was always increasing as Yb3+ doping concentration increased.

Surface modified α-glycine - EuF3: Gd nanoparticles for upconversion luminescence

NASA Astrophysics Data System (ADS)

Mahajan, Manoj P.; Khandpekar, M. M.

2018-04-01

Gadolinium doped EuF3 nanoparticles have been synthesized in the presence of α-glycine via chloride route with subsequent microwave drying. The XRD profile shows hexagonal phase structure with lattice parameters a = b = 6.920 A° and c = 7.085 A° (JCPDS No. 32-0373) with Debye-Scherer particle size of 51 nm. The SEM shows chipped morphology and TEM images exhibit shallow toroid like hexagonal - rounded nanostructures (30 - 50 nm) and their subsequent spontaneous transformation in to hyperboloid shaped nanostructures (200 - 600 nm) possibly with extension of the reaction time. SAED pattern confirms crystalline nature of nanoparticles and the planes are in agreement with XRD Peaks. Comparative FTTR and Raman spectrum shows presence of various functional groups confirming the capping of the glycine on EuF3:Gd core. A TGA/DTA spectrum shows decomposition in two stages. The photoluminescence spectrum shows up conversion luminescence at wavelength 653 nm (red).

Monitoring Delamination of Thermal Barrier Coatings by Near-Infrared and Upconversion Luminescence Imaging

NASA Technical Reports Server (NTRS)

Eldridge, J. I.; Martin, R. E.; Singh, Jogender; Wolfe, Doug E.

2008-01-01

Previous work has demonstrated that TBC delamination can be monitored by incorporating a thin luminescent sublayer that produces greatly increased luminescence intensity from delaminated regions of the TBC. Initial efforts utilized visible-wavelength luminescence from either europium or erbium doped sublayers. This approach exhibited good sensitivity to delamination of electron-beam physical-vapor-deposited (EB-PVD) TBCs, but limited sensitivity to delamination of the more highly scattering plasma-sprayed TBCs due to stronger optical scattering and to interference by luminescence from rare-earth impurities. These difficulties have now been overcome by new strategies employing near-infrared (NIR) and upconversion luminescence imaging. NIR luminescence at 1550 nm was produced in an erbium plus ytterbium co-doped yttria-stabilized zirconia (YSZ) luminescent sublayer using 980-nm excitation. Compared to visible-wavelength luminescence, these NIR emission and excitation wavelengths are much more weakly scattered by the TBC and therefore show much improved depth-probing capabilities. In addition, two-photon upconversion luminescence excitation at 980 nm wavelength produces luminescence emission at 562 nm with near-zero fluorescence background and exceptional contrast for delamination indication. The ability to detect TBC delamination produced by Rockwell indentation and by furnace cycling is demonstrated for both EB-PVD and plasma-sprayed TBCs. The relative strengths of the NIR and upconversion luminescence methods for monitoring TBC delamination are discussed.

Upconversion of Tm3+ ions in BaY2F8

NASA Astrophysics Data System (ADS)

Ruan, Yongfeng; Tsuboi, Taiju

1999-06-01

Up-conversion of red light with wavelength of 660 nm in Tm3+-doped BaY2F8 powder results in the two violet luminescence bands with peaks at 417 and 430 nm and two blue luminescence bands with peaks at 455 and 470 nm. The two violet bands are observed to be stronger than the blue bands. The blue luminescence is also observed by pumping with 993 nm light. The up-conversion is explained by a multiple excited state absorption process.

Multifunctional NaYF4:Yb, Er@mSiO2@Fe3O4-PEG nanoparticles for UCL/MR bioimaging and magnetically targeted drug delivery.

PubMed

Liu, Bei; Li, Chunxia; Ma, Ping'an; Chen, Yinyin; Zhang, Yuanxin; Hou, Zhiyao; Huang, Shanshan; Lin, Jun

2015-02-07

A low toxic multifunctional nanoplatform, integrating both mutimodal diagnosis methods and antitumor therapy, is highly desirable to assure its antitumor efficiency. In this work, we show a convenient and adjustable synthesis of multifunctional nanoparticles NaYF4:Yb, Er@mSiO2@Fe3O4-PEG (MFNPs) based on different sizes of up-conversion nanoparticles (UCNPs). With strong up-conversion fluorescence offered by UCNPs, superparamagnetism properties attributed to Fe3O4 nanoparticles and porous structure coming from the mesoporous SiO2 shell, the as-obtained MFNPs can be utilized not only as a contrast agent for dual modal up-conversion luminescence (UCL)/magnetic resonance (MR) bio-imaging, but can also achieve an effective magnetically targeted antitumor chemotherapy both in vitro and in vivo. Furthermore, the UCL intensity of UCNPs and the magnetic properties of Fe3O4 in the MFNPs were carefully balanced. Silica coating and further PEG modifying can improve the hydrophilicity and biocompatibility of the as-synthesized MFNPs, which was confirmed by the in vitro/in vivo biocompatibility and in vivo long-time bio-distributions tests. Those results revealed that the UCNPs based magnetically targeted drug carrier system we synthesized has great promise in the future for multimodal bio-imaging and targeted cancer therapy.

Smartphone based visual and quantitative assays on upconversional paper sensor.

PubMed

Mei, Qingsong; Jing, Huarong; Li, You; Yisibashaer, Wuerzha; Chen, Jian; Nan Li, Bing; Zhang, Yong

2016-01-15

The integration of smartphone with paper sensors recently has been gain increasing attentions because of the achievement of quantitative and rapid analysis. However, smartphone based upconversional paper sensors have been restricted by the lack of effective methods to acquire luminescence signals on test paper. Herein, by the virtue of 3D printing technology, we exploited an auxiliary reusable device, which orderly assembled a 980nm mini-laser, optical filter and mini-cavity together, for digitally imaging the luminescence variations on test paper and quantitative analyzing pesticide thiram by smartphone. In detail, copper ions decorated NaYF4:Yb/Tm upconversion nanoparticles were fixed onto filter paper to form test paper, and the blue luminescence on it would be quenched after additions of thiram through luminescence resonance energy transfer mechanism. These variations could be monitored by the smartphone camera, and then the blue channel intensities of obtained colored images were calculated to quantify amounts of thiram through a self-written Android program installed on the smartphone, offering a reliable and accurate detection limit of 0.1μM for the system. This work provides an initial demonstration of integrating upconversion nanosensors with smartphone digital imaging for point-of-care analysis on a paper-based platform. Copyright © 2015 Elsevier B.V. All rights reserved.

Nd3+, Yb3+ and Ho3+ Codoped Oxyfluoride Glass Ceramics with High Efficient Green Upconversion Luminescence

NASA Astrophysics Data System (ADS)

Zhang, Jun-Jie; Kawamoto, Yoji; Dai, Shi-Xun; Zhang, Li-Yan; Hu, Li-Li

2004-06-01

New oxyfluoride glasses and glass ceramic codoped with Nd3+, Yb3+ and Ho3+ were prepared. The x-ray diffraction analysis revealed that the heat treatments of the oxyfluoride glasses could cause the precipitation of (Nd3+, Yb3+, Ho3+)-doped fluorite-type crystals. Very strong green up-conversion luminescence due to the Ho3+: (5F4, 5S2)rightarrow5I8 transition under 800-nm excitation was observed in these transparent glass ceramics. The intensity of the green up-conversion luminescence in a 1-mol% YbF3-containing glass ceramic was found to be about 120 times stronger than that in the precursor oxyfluoride glass. The reason for the highly efficient Ho3+ up-conversion luminescence in the oxyfluoride glass ceramics is discussed.

Synthesis, Structural Characterization and Up-Conversion Luminescence Properties of NaYF4:Er3+,Yb3+@MOFs Nanocomposites

NASA Astrophysics Data System (ADS)

Giang, Lam Thi Kieu; Marciniak, Lukasz; Huy, Tran Quang; Vu, Nguyen; Le, Ngo Thi Hong; Binh, Nguyen Thanh; Lam, Tran Dai; Minh, Le Quoc

2017-10-01

This paper describes a facile synthesis of NaYF4:Er3+,Yb3+ nanoparticles embraced in metal-organic frameworks (MOFs), known as NaYF4:Er3+, Yb3+@MOFs core/shell nanostructures, by using iron(III) carboxylate (MIL-100) and zeolitic imidazolate frameworks (ZIF-8). Morphological, structural and optical characterization of these nanostructures were investigated by field emission-scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, and up-conversion luminescence measurements. Results showed that spherical-shaped NaYF4:Er3+,Yb3+@MIL-100 nanocomposites with diameters of 150-250 nm, and rod-shaped NaYF4:Er3+,Yb3+@ZIF-8 nanocomposites with lengths of 300-550 nm, were successfully synthesized. Under a 980-nm laser excitation at room temperature, the NaYF4:Er3+,Yb3+@MOFs nanocomposites exhibited strong up-conversion luminescence with two emission bands in the green part of spectrum at 520 nm and 540 nm corresponding to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+ ions, respectively, and a red emission band at 655 nm corresponding to the 4F9/2 → 4I15/2 transition of Er3+ ions. The above properties of NaYF4:Er3+,Yb3+@MOFs make them promising candidates for applications in biotechnology.

A new near infrared photosensitizing nanoplatform containing blue-emitting up-conversion nanoparticles and hypocrellin A for photodynamic therapy of cancer cells

NASA Astrophysics Data System (ADS)

Jin, Shan; Zhou, Liangjun; Gu, Zhanjun; Tian, Gan; Yan, Liang; Ren, Wenlu; Yin, Wenyan; Liu, Xiaodong; Zhang, Xiao; Hu, Zhongbo; Zhao, Yuliang

2013-11-01

The utilization of up-conversion nanoparticles (UCNPs) for photodynamic therapy (PDT) has gained significant interest due to their unique ability to convert near infrared light to UV/visible light. Previous work mainly focused on the fabrication of green and red emitting UCNPs to load photosensitizers (PSs) for PDT. In this work, we firstly developed a new multifunctional nanoplatform combining blue-emitting UCNPs with blue-light excited PS (hypocrellin A, HA) as a NIR photosensitizing nanoplatform for PDT of cancer cells. Tween 20 coated NaYbF4:Tm, Gd@NaGdF4 UCNPs (Tween 20-UCNPs) with strong blue up-conversion luminescence and good water dispersibility were prepared for use as PS carriers. The blue emission band matched well with the efficient absorption band of HA, thereby facilitating the resonance energy transfer from UCNPs to HA and then activating HA to produce singlet oxygen (1O2). The in vitro study showed that these Tween 20-UCNPs@HA complexes could efficiently produce 1O2 to kill cancer cells under 980 nm NIR excitation. Moreover, these Gd3+ and Yb3+ containing nanoparticles also exhibited positive contrast effects in both T1 weighted magnetic resonance imaging (MRI) and computed tomography (CT) imaging, making them become a multifunctional platform for simultaneous PDT and bio-imaging.The utilization of up-conversion nanoparticles (UCNPs) for photodynamic therapy (PDT) has gained significant interest due to their unique ability to convert near infrared light to UV/visible light. Previous work mainly focused on the fabrication of green and red emitting UCNPs to load photosensitizers (PSs) for PDT. In this work, we firstly developed a new multifunctional nanoplatform combining blue-emitting UCNPs with blue-light excited PS (hypocrellin A, HA) as a NIR photosensitizing nanoplatform for PDT of cancer cells. Tween 20 coated NaYbF4:Tm, Gd@NaGdF4 UCNPs (Tween 20-UCNPs) with strong blue up-conversion luminescence and good water dispersibility were prepared for use as PS carriers. The blue emission band matched well with the efficient absorption band of HA, thereby facilitating the resonance energy transfer from UCNPs to HA and then activating HA to produce singlet oxygen (1O2). The in vitro study showed that these Tween 20-UCNPs@HA complexes could efficiently produce 1O2 to kill cancer cells under 980 nm NIR excitation. Moreover, these Gd3+ and Yb3+ containing nanoparticles also exhibited positive contrast effects in both T1 weighted magnetic resonance imaging (MRI) and computed tomography (CT) imaging, making them become a multifunctional platform for simultaneous PDT and bio-imaging. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03515h

Lanthanide-doped upconversion nanocrystals: Synthesis and optical properties study

NASA Astrophysics Data System (ADS)

Sun, Qiang

Upconversion phosphor materials have attracted considerable attention in recent years for their potential applications in a wide range of fields, including three-dimensional displays technologies, bio-imaging and photovoltaics. This dissertation aims to develop novel lanthanide-doped upconversion luminescent nanomaterials by using wet chemistry methods. Considerable efforts have been devoted to manipulating the optical properties of the synthesized lanthanide-doped nanoparticles under excitation of different wavelengths, for example, 808, 980 and 1532 nm. In the first research work, a novel core-shell-shell design has been developed for finely tuning of energy migration upconversion of activators without long-lived mediated states, such as Eu3+ and Tb3+ upon excitation at 808 nm by using Nd3+ as sensitizer. Exquisite control the composition of each layer gives rise to maximized upconversion emissions of the activators. For example, with the use of core layer for energy harvesting (NaGdF4:Yb/Nd, active core), the optimal doping concentrations of Eu3+ and Tb3+ is fixed to 15 and 15 mol%, respectively. In contrast, active shell can also provide access to strong upconversion of Eu3+ and Tb3+ by doping Nd (40 mol%) into the outmost layer. Note that the effect of active shell is much stronger than active core in generating upconversion emissions of Eu3+ and Tb3+. Next, upconversion emission tuning of Er/Tm/Yb-doped NaYF4 upconversion nanoparticles has been conducted under excitation at 1532 nm. The output color of the nanoparticles is tunable by changing the doping levels of the lanthanides. With the use of core-shell design, the optical properties of the doped nanoparticles can be further optimized, for example, strongest upconversion emission was observed for NaYF4:Er(10 mol%) NaYF4:Er(0.5 mol%) with a relative emission of green-to-red of 1.2. This work provides a new dimension to control the color output of upconversion nanoparticles. It should be noted that the emission profiles of upconversion nanoparticles will be further enriched by using a combination of different excitation wavelengths. Finally, the orthorhombic-phase K2YF5 nanobelts doped with upconverting lanthanide ions (Er3+ and Tm3+) were synthesized by using a coprecipitation method. The growth kinetics of the nanobelts can be regulated by either control of the volume ratio of oleic acid in the synthetic system or period of reaction time. It was found that desirable lanthanide-doped K2YF5 nanobelts were yielded through the use of long time high-temperature annealing treatment (270 °C, 6 h) in the presence of low content of oleic acid. The assynthesized lanthanide-doped K2YF5 nanobelts show intense upconversion emissions upon excitation at 980 nm. For example, bright yellow emission was observed from K2YF5:Yb/Er(18/2 mol%), resulting from weak optical transitions of 2H11/2 → 4I15/2 (520 nm) and 4S3/2 → 4I15/2 (540 nm) and a dominant transition of 4F9/2 → 4I15/2 (centered at 650 nm) of the doped Er3+. In the case of K2YF5:Yb/Tm(30/0.5 mol%) nanobelts, three main emission bands centered at 479 (blue), 650 (red) and 800 nm (NIR) corresponding to 1D2 → 3H6, 1D2 → 3H4, and 3H4 ¨ 3H6 transition of Tm3+ were observed.

Structure and up-conversion luminescence in sol-gel derived Er 3+-Yb 3+ co-doped SiO 2:PbF 2 nano-glass-ceramics

NASA Astrophysics Data System (ADS)

del-Castillo, J.; Yanes, A. C.; Méndez-Ramos, J.; Tikhomirov, V. K.; Rodríguez, V. D.

2009-11-01

Transparent oxyfluoride nano-glass-ceramics 90(SiO 2)10(PbF 2) co-doped with 0.3 Yb 3+ and 0.1 Er 3+ (mol%) have been prepared by thermal treatment of precursor sol-gel glasses. X-ray diffraction and high resolution transmission electron microscopy analysis pointed out a precipitation of cubic β-PbF 2 nanocrystals of certain diameter in nano-glass-ceramics varying from 10 to 20 nm depending on heat treatment conditions. The incorporation of Yb 3+ and Er 3+ dopants in these nanocrystals has been confirmed by signatures of luminescence spectroscopy. Up-conversion luminescence pumped at 980 nm has been detected. Colour tuneability of up-conversion luminescence varying pump power has been analyzed in terms of standard chromaticity diagram. This tuneability opens applications for up-conversion phosphors and three-dimensional optical recording.

A Paper-Based Sandwich Format Hybridization Assay for Unlabeled Nucleic Acid Detection Using Upconversion Nanoparticles as Energy Donors in Luminescence Resonance Energy Transfer.

PubMed

Zhou, Feng; Noor, M Omair; Krull, Ulrich J

2015-09-24

Bioassays based on cellulose paper substrates are gaining increasing popularity for the development of field portable and low-cost diagnostic applications. Herein, we report a paper-based nucleic acid hybridization assay using immobilized upconversion nanoparticles (UCNPs) as donors in luminescence resonance energy transfer (LRET). UCNPs with intense green emission served as donors with Cy3 dye as the acceptor. The avidin functionalized UCNPs were immobilized on cellulose paper and subsequently bioconjugated to biotinylated oligonucleotide probes. Introduction of unlabeled oligonucleotide targets resulted in a formation of probe-target duplexes. A subsequent hybridization of Cy3 labeled reporter with the remaining single stranded portion of target brought the Cy3 dye in close proximity to the UCNPs to trigger a LRET-sensitized emission from the acceptor dye. The hybridization assays provided a limit of detection (LOD) of 146.0 fmol and exhibited selectivity for one base pair mismatch discrimination. The assay was functional even in undiluted serum samples. This work embodies important progress in developing DNA hybridization assays on paper. Detection of unlabeled targets is achieved using UCNPs as LRET donors, with minimization of background signal from paper substrates owing to the implementation of low energy near-infrared (NIR) excitation.

Crystal growth and upconversion luminescent properties of KLu2F7:Yb,Er nanocrystals

NASA Astrophysics Data System (ADS)

Xu, Dekang; Yao, Lu; Lin, Hao; Yang, Shenghong; Zhang, Yueli

2018-05-01

Crystal growth of KLu2F7 nanocrystals is investigated by dosage- and time-dependent analysis. XRD patterns reveal the phase transition along with the dosage of fluorine source and reaction times, where the cubic-phase KLu3F10 turns into orthorhombic KLu2F7. TEM images show that the dimensions of as-prepared samples are below a hundred nanometers, with different shapes from hexagonal plate to hexagonal rod. The upconversion properties of the as-prepared samples are investigated. It is found that the upconversion emission is lowered as the shape of the samples varies. Moreover, the orthorhombic KLu2F7:Yb,Er nanocrystals present more enormous upconversion luminescence than the cubic counterparts. In a word, the orthorhombic nanocrystals are found to be good candidate for upconversion luminescence and of great importance for potential applications in solar cells, multicolor display and bioimaging.

Upconversion improvement in KLaF4:Yb3+/Er3+ nanoparticles by doping Al3+ ions

NASA Astrophysics Data System (ADS)

Zhou, Haifang; Wang, Xiechun; Lai, Yunfeng; Cheng, Shuying; Zheng, Qiao; Yu, Jinlin

2017-10-01

Rare-earth ion-doped upconversion (UC) materials show great potential applications in optical and optoelectronic devices due to their novel optical properties. In this work, hexagonal KLaF4:Yb3+/Er3+ nanoparticles (NPs) were successfully synthesized by a hydrothermal method, and remarkably enhanced upconversion luminescence in green and red emission bands in KLaF4:Yb3+/Er3+ NPs has been achieved by doping Al3+ ions under 980 nm excitation. Compared to the aluminum-free KLaF4:Yb3+/Er3+ NPs sample, the UC fluorescence intensities of the green and red emissions of NPs doped with 10 at.% Al3+ ions were significantly enhanced by 5.9 and 7.3 times, respectively. Longer lifetimes of the doped samples were observed for the 4S3/2 state and 4F9/2 state. The underlying reason for the UC enhancement by doping Al3+ ions was mainly ascribed to distortion of the local symmetry around Er3+ ions and adsorption reduction of organic ligands on the surface of NPs. In addition, the influence of doping Al3+ ions on the structure and morphology of the NPs samples was also discussed.

Simultaneous aptasensor for multiplex pathogenic bacteria detection based on multicolor upconversion nanoparticles labels.

PubMed

Wu, Shijia; Duan, Nuo; Shi, Zhao; Fang, Congcong; Wang, Zhouping

2014-03-18

A highly sensitive and specific multiplex method for the simultaneous detection of three pathogenic bacteria was fabricated using multicolor upconversion nanoparticles (UCNPs) as luminescence labels coupled with aptamers as the molecular recognition elements. Multicolor UCNPs were synthesized via doping with various rare-earth ions to obtain well-separated emission peaks. The aptamer sequences were selected using the systematic evolution of ligands by exponential enrichment (SELEX) strategy for Staphylococcus aureus, Vibrio parahemolyticus, and Salmonella typhimurium. When applied in this method, aptamers can be used for the specific recognition of the bacteria from complex mixtures, including those found in real food matrixes. Aptamers and multicolor UCNPs were employed to selectively capture and simultaneously quantify the three target bacteria on the basis of the independent peaks. Under optimal conditions, the correlation between the concentration of three bacteria and the luminescence signal was found to be linear from 50-10(6) cfu mL(-1). Improved by the magnetic separation and concentration effect of Fe3O4 magnetic nanoparticles, the limits of detection of the developed method were found to be 25, 10, and 15 cfu mL(-1) for S. aureus, V. parahemolyticus, and S. typhimurium, respectively. The capability of the bioassay in real food samples was also investigated, and the results were consistent with experimental results obtained from plate-counting methods. This proposed method for the detection of various pathogenic bacteria based on multicolor UCNPs has great potential in the application of food safety and multiplex nanosensors.

Smart Self-Assembled Nanosystem Based on Water-Soluble Pillararene and Rare-Earth-Doped Upconversion Nanoparticles for pH-Responsive Drug Delivery.

PubMed

Li, Haihong; Wei, Ruoyan; Yan, Gui-Hua; Sun, Ji; Li, Chunju; Wang, Haifang; Shi, Liyi; Capobianco, John A; Sun, Lining

2018-02-07

Exploring novel drug delivery systems with good stability and new structure to integrate pillararene and upconversion nanoparticles (UCNPs) into one system continues to be an important challenge. Herein, we report a novel preparation of a supramolecular upconversion nanosystem via the host-guest complexation based on carboxylate-based pillar[5]arene (WP5) and 15-carboxy-N,N,N-trialkylpentadecan-1-ammonium bromide (1)-functionalized UCNPs to produce WP5⊃1-UCNPs that can be loaded with the chemotherapeutic drug doxorubicin (DOX). Importantly, the WP5 on the surface of the drug-loaded nanosystem can be efficiently protonated under acidic conditions, resulting in the collapse of the nanosystem and drug release. Moreover, cellular uptake confirms that the nanosystem can enter human cervical cancer (HeLa) cells, resulting in drug accumulation in the cells. More importantly, cytotoxicity experiments demonstrated the excellent biocompatibility of WP5⊃1-UCNPs without loading DOX and that the nanosystem DOX-WP5⊃1-UCNPs exhibited an ability of killing HeLa cells effectively. We also investigated magnetic resonance imaging and upconversion luminescence imaging, which may be employed as visual imaging agents in cancer diagnosis and treatment. Thus, in the present work, we show a simple yet powerful strategy to combine UCNPs and pillar[5]arene to produce a unified nanosystem for dual-mode bioimaging-guided therapeutic applications.

High-Precision Pinpointing of Luminescent Targets in Encoder-Assisted Scanning Microscopy Allowing High-Speed Quantitative Analysis.

PubMed

Zheng, Xianlin; Lu, Yiqing; Zhao, Jiangbo; Zhang, Yuhai; Ren, Wei; Liu, Deming; Lu, Jie; Piper, James A; Leif, Robert C; Liu, Xiaogang; Jin, Dayong

2016-01-19

Compared with routine microscopy imaging of a few analytes at a time, rapid scanning through the whole sample area of a microscope slide to locate every single target object offers many advantages in terms of simplicity, speed, throughput, and potential for robust quantitative analysis. Existing techniques that accommodate solid-phase samples incorporating individual micrometer-sized targets generally rely on digital microscopy and image analysis, with intrinsically low throughput and reliability. Here, we report an advanced on-the-fly stage scanning method to achieve high-precision target location across the whole slide. By integrating X- and Y-axis linear encoders to a motorized stage as the virtual "grids" that provide real-time positional references, we demonstrate an orthogonal scanning automated microscopy (OSAM) technique which can search a coverslip area of 50 × 24 mm(2) in just 5.3 min and locate individual 15 μm lanthanide luminescent microspheres with standard deviations of 1.38 and 1.75 μm in X and Y directions. Alongside implementation of an autofocus unit that compensates the tilt of a slide in the Z-axis in real time, we increase the luminescence detection efficiency by 35% with an improved coefficient of variation. We demonstrate the capability of advanced OSAM for robust quantification of luminescence intensities and lifetimes for a variety of micrometer-scale luminescent targets, specifically single down-shifting and upconversion microspheres, crystalline microplates, and color-barcoded microrods, as well as quantitative suspension array assays of biotinylated-DNA functionalized upconversion nanoparticles.

The effect of micro-structure on upconversion luminescence of Nd3+/Yb3+ co-doped La2O3-TiO2-ZrO2 glass-ceramics

NASA Astrophysics Data System (ADS)

Zhang, Minghui; Wen, Haiqin; Pan, Xiuhong; Yu, Jianding; Jiang, Meng; Yu, Huimei; Tang, Meibo; Gai, Lijun; Ai, Fei

2018-03-01

Nd3+/Yb3+ co-doped La2O3-TiO2-ZrO2 glasses have been prepared by aerodynamic levitation method. The glasses show high refractive index of 2.28 and Abbe number of 18.3. Glass-ceramics heated at 880 °C for 50 min perform the strongest upconversion luminescence. X-ray diffraction patterns of glass-ceramics with different depths indicate that rare earth ions restrain crystallization. Body crystallization mechanism mixed with surface crystallization is confirmed in the heat treatment. Surface crystals achieve priority to grow, resulting in important effects on upconversion luminescence. The results of atomic force microscope and scanning electron microscope indicate that crystal particles with uniform size distribute densely and homogenously on the surface and large amount of glass matrix exists in the glass ceramics heated at 880 °C for 50 min. Crystals in the glass-ceramics present dense structure and strong boundaries, which can reduce the mutual nonradiative relaxation rate among rare earth ions and then improve upconversion luminescence effectively. Based on micro-structural study, the mechanism that upconversion luminescence can be improved by heat treatment has been revealed. The results of micro-structural analysis agree well with the spectra.

Developing core-shell upconversion nanoparticles for optical encoding

NASA Astrophysics Data System (ADS)

Huang, Kai

Lanthanide-doped upconversion nanoparticles (UCNPs) are an emerging class of luminescent materials that emit UV or visible light under near infra-red (NIR) excitations, thereby possessing a large anti-Stokes shift property. Also considering their sharp emission bands, excellent photo- and chemical stability, and almost zero auto-fluorescence of their NIR excitation, UCNPs are advantageous for optical encoding. Fabricating core-shell structured UCNPs provides a promising strategy to tune and enhance their upconverting luminescence. However, the energy transfer between core and shell had been rarely studied. Moreover, this strategy had been limited by the difficulty of coating thick shells onto the large cores of UCNPs. To overcome these constraints, the overall aim of this project is to study the inter-layers energy transfer in core-shell UCNPs and to develop an approach for coating thicker shell onto the core UCNPs, in order to fabricate UCNPs with enhanced and tunable luminescence for optical encoding. The strategy for encapsulating UCNPs into hydrogel droplet to fabricate multi-color bead barcodes has also been developed. Firstly, to study the inter-layers energy transfer between the core and shell of coreshell UCNPs, the activator and sensitizer ions were separately doped in the core or shell by fabricating NaYF4:Er NaYF4:Yb and NaYF4:Yb NaYF4:Er UCNPs. This eliminated the intra-layer energy transfer, resulting in a luminescence that is solely based on the energy transfer between layers, which facilitated the study of inter-layers energy transfer. The results demonstrated that the NaYF4:Yb NaYF4:Er structure, with sensitizer ions doped in the core, was preferable because of the strong luminescence, through minimizing the cross relaxations between Er3+ and Yb3+ and the surface quenching. Based on these information, a strategy of enhancing and tuning upconversion luminescence of core-shell UCNPs by accumulating sensitizer in the core has been developed. Next, a strategy of coating a thick shell by lutetium doping has been developed. With a smaller ion radius compared to Y3+, when Lu3+ partially replace Y3+ in the NaYF4 UCNPs during nanoparticle synthesis, nucleation process is suppressed and the growth process is promoted, which are favorable for increasing the nanoparticle size and coating a thicker shell onto the core UCNPs. Through the rational doping of Lu3+, core UCNPs with bigger sizes and enhanced luminescence were produced. Using NaLuF4 as the shell material, shells with tremendous thickness were coated onto core UCNPs, with the shell/core ratio of up to 10:1. This led to the fabrication of multi-color UCNPs with well-designed core-shell structures with multiple layers and controllable thicknesses. Finally, a strategy of encapsulating these UCNPs to produce optically encoded micro-beads through high-throughput microfluidics has been developed. The hydrophobic UCNPs were first modified with Pluronic F127 to render them hydrophilic and uniformly distributed in the poly (ethylene glycol) diacrylate (PEGDA) hydrogel precursor. Droplets of the hydrogel precursor were formed in a microfluidic device and cross-linked into micro-beads under UV irradiation. Through encapsulation of multi-color UCNPs and by controlling their ratio, optically encoded multi-color micro-beads have been easily fabricated. These multi-color UCNPs and micro-bead barcodes have great potential for use in multiplexed bioimaging and detection.

Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect

PubMed Central

Gao, Dangli; Tian, Dongping; Zhang, Xiangyu; Gao, Wei

2016-01-01

Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb3+/Er3+ microtube under near infrared light excitation. The mechanism of upconversion propagation, based on the optical waveguide effect accompanied with energy migration, is proposed. The efficiency of luminescence output is highly dependent on the concentration of dopant ions, excitation power, morphology, and crystallinity of tube as an indirect evidence of the existence of the optical actived waveguide effect. These findings provide the possibility for the construction of upconversion fiber laser. PMID:26926491

Color Tunable and Upconversion Luminescence in Yb-Tm Co-Doped Yttrium Phosphate Inverse Opal Photonic Crystals.

PubMed

Wang, Siqin; Qiu, Jianbei; Wang, Qi; Zhou, Dacheng; Yang, Zhengwen

2016-04-01

For this paper, YPO4: Tm, Yb inverse opals with the photonic band gaps at 475 nm and 655 nm were prepared by polystyrene colloidal crystal templates. We investigated the influence of photonic band gaps on the Tm-Yb upconversion emission which was in the YPO4: Tm Yb inverse opal photonic crystals. Comparing with the reference sample, significant suppression of both the blue and red upconversion luminescence of Tm3+ ions were observed in the inverse opals. The color purity of the blue emission was improved in the inverse opal by the suppression of red upconversion emission. Additionally, mechanism of upconversion emission in the inverse opal was discussed. We believe that the present work will be valuable for not only the foundational study of upconversion emission modification but also the development of new optical devices in upconversion lighting and display.

A core/satellite multifunctional nanotheranostic for in vivo imaging and tumor eradication by radiation/photothermal synergistic therapy.

PubMed

Xiao, Qingfeng; Zheng, Xiangpeng; Bu, Wenbo; Ge, Weiqiang; Zhang, Shengjian; Chen, Feng; Xing, Huaiyong; Ren, Qingguo; Fan, Wenpei; Zhao, Kuaile; Hua, Yanqing; Shi, Jianlin

2013-09-04

To integrate photothermal ablation (PTA) with radiotherapy (RT) for improved cancer therapy, we constructed a novel multifunctional core/satellite nanotheranostic (CSNT) by decorating ultrasmall CuS nanoparticles onto the surface of a silica-coated rare earth upconversion nanoparticle. These CSNTs could not only convert near-infrared light into heat for effective thermal ablation but also induce a highly localized radiation dose boost to trigger substantially enhanced radiation damage both in vitro and in vivo. With the synergistic interaction between PTA and the enhanced RT, the tumor could be eradicated without visible recurrence in 120 days. Notably, hematological analysis and histological examination unambiguously revealed their negligible toxicity to the mice within a month. Moreover, the novel CSNTs facilitate excellent upconversion luminescence/magnetic resonance/computer tomography trimodal imagings. This multifunctional nanocomposite is believed to be capable of playing a vital role in future oncotherapy by the synergistic effects between enhanced RT and PTA under the potential trimodal imaging guidance.

Upconversion properties of Er3+/Yb3+ co-doped TeO2-TiO2-K2O glasses.

PubMed

Su, Fangning; Deng, Zaide

2006-01-01

The Er3+/Yb3+ co-doped TeO2-TiO2-K2O glasses were prepared by conventional melting procedures, and their upconversion spectra were performed. The dependence of luminescence intensity on the ratio of Yb3+/Er3+ was studied, and the relationship between green upconversion luminescence intensity and Er3+ concentration is discussed in detail. The 546 nm green upconversion luminescence intensity is optimised in the studied glasses either when the Yb3+/Er3+ ratio is 25/1 and Er3+ concentration is 0.1 mol%, or when the Yb3+/Er3+ ratio is 10/1 and Er3+ concentration is 0.15 mol%. These glasses could be one of the potential candidates for LD pumping microchip solid-state lasers.

Luminescence upconversion under hydrostatic pressure in the 3d-metal systems Ti2+:NaCl and Ni2+:CsCdCl3

NASA Astrophysics Data System (ADS)

Wenger, Oliver S.; Salley, G. Mackay; Valiente, Rafael; Güdel, Hans U.

2002-06-01

We present a study of upconversion materials and processes under external hydrostatic pressure. The near-infrared to visible photon upconversion properties of Ti2+-doped NaCl and Ni2+-doped CsCdCl3 at 15 K are studied as a function of external hydrostatic pressure. It is found that in Ti2+:NaCl pressure can be used to switch on an efficient upconversion mechanism, which is inactive at ambient pressure, leading to an order-of-magnitude enhancement of the overall upconversion efficiency of this material. For Ni2+:CsCdCl3 it is demonstrated that upconversion luminescence excitation spectroscopy can be used to study the pressure dependence of excited state absorption transitions. The results demonstrate the ability to tune upconversion properties by altering the local crystal field of active ions, in addition to probing the pressure dependence of excited state absorption transitions via upconversion spectroscopy.

Neuroendocrine Tumor-Targeted Upconversion Nanoparticle-Based Micelles for Simultaneous NIR-Controlled Combination Chemotherapy and Photodynamic Therapy, and Fluorescence Imaging.

PubMed

Chen, Guojun; Jaskula-Sztul, Renata; Esquibel, Corinne R; Lou, Irene; Zheng, Qifeng; Dammalapati, Ajitha; Harrison, April; Eliceiri, Kevin W; Tang, Weiping; Chen, Herbert; Gong, Shaoqin

2017-02-23

Although neuroendocrine tumors (NETs) are slow growing, they are frequently metastatic at the time of discovery and no longer amenable to curative surgery, emphasizing the need for the development of other treatments. In this study, multifunctional upconversion nanoparticle (UCNP)-based theranostic micelles are developed for NET-targeted and near-infrared (NIR)-controlled combination chemotherapy and photodynamic therapy (PDT), and bioimaging. The theranostic micelle is formed by individual UCNP functionalized with light-sensitive amphiphilic block copolymers poly(4,5-dimethoxy-2-nitrobenzyl methacrylate)-polyethylene glycol (PNBMA-PEG) and Rose Bengal (RB) photosensitizers. A hydrophobic anticancer drug, AB3, is loaded into the micelles. The NIR-activated UCNPs emit multiple luminescence bands, including UV, 540 nm, and 650 nm. The UV peaks overlap with the absorption peak of photocleavable hydrophobic PNBMA segments, triggering a rapid drug release due to the NIR-induced hydrophobic-to-hydrophilic transition of the micelle core and thus enabling NIR-controlled chemotherapy. RB molecules are activated via luminescence resonance energy transfer to generate 1 O 2 for NIR-induced PDT. Meanwhile, the 650 nm emission allows for efficient fluorescence imaging. KE108, a true pansomatostatin nonapeptide, as an NET-targeting ligand, drastically increases the tumoral uptake of the micelles. Intravenously injected AB3-loaded UCNP-based micelles conjugated with RB and KE108-enabling NET-targeted combination chemotherapy and PDT-induce the best antitumor efficacy.

Exonuclease III-Assisted Upconversion Resonance Energy Transfer in a Wash-Free Suspension DNA Assay.

PubMed

Chen, Yinghui; Duong, Hien T T; Wen, Shihui; Mi, Chao; Zhou, Yingzhu; Shimoni, Olga; Valenzuela, Stella M; Jin, Dayong

2018-01-02

Sensitivity is the key in optical detection of low-abundant analytes, such as circulating RNA or DNA. The enzyme Exonuclease III (Exo III) is a useful tool in this regard; its ability to recycle target DNA molecules results in markedly improved detection sensitivity. Lower limits of detection may be further achieved if the detection background of autofluorescence can be removed. Here we report an ultrasensitive and specific method to quantify trace amounts of DNA analytes in a wash-free suspension assay. In the presence of target DNA, the Exo III recycles the target DNA by selectively digesting the dye-tagged sequence-matched probe DNA strand only, so that the amount of free dye removed from the probe DNA is proportional to the number of target DNAs. Remaining intact probe DNAs are then bound onto upconversion nanoparticles (energy donor), which allows for upconversion luminescence resonance energy transfer (LRET) that can be used to quantify the difference between the free dye and tagged dye (energy acceptor). This scheme simply avoids both autofluorescence under infrared excitation and many tedious washing steps, as the free dye molecules are physically located away from the nanoparticle surface, and as such they remain "dark" in suspension. Compared to alternative approaches requiring enzyme-assisted amplification on the nanoparticle surface, introduction of probe DNAs onto nanoparticles only after DNA hybridization and signal amplification steps effectively avoids steric hindrance. Via this approach, we have achieved a detection limit of 15 pM in LRET assays of human immunodeficiency viral DNA.

Up-conversion green emission of Yb3+/Er3+ ions doped YVO4 nanocrystals obtained via modified Pechini's method

NASA Astrophysics Data System (ADS)

Szczeszak, Agata; Runowski, Marcin; Wiglusz, Rafal J.; Grzyb, Tomasz; Lis, Stefan

2017-12-01

A series of lanthanide doped yttrium vanadates were prepared by Pechini's method (sol-gel process). The as-prepared precursors, in the presence of citric acid, were calcined in the temperature range of 600-900 °C. The obtained products were composed of small nanoparticles, in the size range of 20-50 nm, depending on the annealing temperature, exhibiting a bright green up-conversion emission, under NIR laser irradiation, and emission lifetimes in the range of 4.7-18.3 μs. Their structural, morphological and spectroscopic properties were investigated in detail by XRD, HR-TEM including FFT analysis, EDX and spectroscopic techniques (emission, power dependence and emission kinetics). The luminescence quenching phenomenon, manifested in a decrease of up-conversion intensity and shortening of emission lifetime, was observed with increasing of the Yb3+ ion concentration and decreasing the particle size. The optimal concentration of the Yb3+ ions was found to be 15 mol% (YVO4: Yb3+ 15 mol%, Er3+ 2 mol%).

Multifunctional Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles synthesized by reverse micelle method

PubMed Central

Gavrilović, Tamara V.; Jovanović, Dragana J.; Lojpur, Vesna; Dramićanin, Miroslav D.

2014-01-01

Synthesis of Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4 nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu3+-doped GdVO4 nanoparticles emit red light through downconversion upon UV excitation. Er3+/Yb3+-doped GdVO4 nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980 nm) into visible green light. The ratio of green emissions from 2H11/2 → 2I15/2 and 4S3/2 → 4I15/2 transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K−1, which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers. PMID:24572638

Multifunctional Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles synthesized by reverse micelle method

NASA Astrophysics Data System (ADS)

Gavrilović, Tamara V.; Jovanović, Dragana J.; Lojpur, Vesna; Dramićanin, Miroslav D.

2014-02-01

Synthesis of Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4 nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu3+-doped GdVO4 nanoparticles emit red light through downconversion upon UV excitation. Er3+/Yb3+-doped GdVO4 nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980 nm) into visible green light. The ratio of green emissions from 2H11/2 --> 2I15/2 and 4S3/2 --> 4I15/2 transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K-1, which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers.

Multifunctional Eu3+- and Er3+/Yb3+-doped GdVO4 nanoparticles synthesized by reverse micelle method.

PubMed

Gavrilović, Tamara V; Jovanović, Dragana J; Lojpur, Vesna; Dramićanin, Miroslav D

2014-02-27

Synthesis of Eu(3+)- and Er(3+)/Yb(3+)-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4 nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu(3+)-doped GdVO4 nanoparticles emit red light through downconversion upon UV excitation. Er(3+)/Yb(3+)-doped GdVO4 nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980 nm) into visible green light. The ratio of green emissions from (2)H11/2 → (2)I15/2 and (4)S3/2 → (4)I15/2 transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K(-1), which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers.

Clear-cut observation of clearance of sustainable upconverting nanoparticles from lymphatic system of small living mice

NASA Astrophysics Data System (ADS)

Park, Hye Sun; Nam, Sang Hwan; Kim, Jongwoo; Shin, Hyung Seon; Suh, Yung Doug; Hong, Kwan Soo

2016-06-01

The significance of lymphatic system has gathered great attention for immunotechnology related to cancer metastasis and immunotherapy. To develop innovative immunodiagnostics and immunotherapy in in vivo environments, it is very important to understand excretion pathways and clearance of injected cargoes. Herein, we employed Tm3+-doped upconverting nanoparticles (UCNPs) with versatile advantages suitable for long-term non-invasive in vivo optical imaging and tracking. Transport and retention of the UCNPs in the lymphatic system were evaluated with high-quality NIR-to-NIR upconversion luminescence (UCL) imaging. We obtained their kinetic luminescence profiles for the injection site and sentinel lymph node (SLN) and observed luminescence signals for one month; we also examined UCL images in SLN tissues, organs, and faeces at each time point. We speculate that the injected UCNPs in a footpad of a small mouse are transported rapidly from the lymphatic system to the blood system and then eventually result in an efficient excretion by the hepatobiliary route. These results will support development of novel techniques for SLN biopsy as well as immunotechnology.

Intense upconversion luminescence and effect of local environment for Tm3+/Yb3+ co-doped novel TeO2-BiCl3 glass system.

PubMed

Wang, Guonian; Dai, Shixun; Zhang, Junjie; Wen, Lei; Yang, Jianhu; Jiang, Zhonghong

2006-05-15

We present the results of a study that uses theoretical and experimental methods to investigate the characteristics of the upconversion luminescence of Tm3+/Yb3+ codoped TeO2-BiCl3 glass system as a function of the BiCl3 fraction. These glasses are potentially important in the design of upconversion fiber lasers. Effect of local environment around Tm3+ on upconversion fluorescence intensity was analyzed by theoretical calculations. The structure and spectroscopic properties were investigated in the experiments by measuring the Raman spectra, IR transmission spectra, and absorption and fluorescence intensities at room temperature. The results indicate that blue luminescence quantum efficiency increases with increasing BiCl3 content from 10 to 60 mol%, which were interpreted by the increase of asymmetry of glass structure, decrease of phonon energy and removing of OH- groups.

Synthesis and characterization of α-NaYF{sub 4}: Yb, Er nanoparticles by reverse microemulsion method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gunaseelan, M.; Senthilselvan, J., E-mail: jsselvan@hotmail.com

2016-05-06

A simple and cost effective reverse microemulsion system was newly designed to synthesis NaYF{sub 4}:20%Yb,2%Er upconverting luminescent nanoparticles. XRD results confirms the cubic structure of NaYF{sub 4} nanophosphor in the as prepared condition without any other impurity phases. The as-prepared sample itself having highly crystalline nanoparticle with well dispersed uniform morphology is the advantage of this reverse microemulsion process. HRTEM images of as prepared and calcined samples revealed spherical nanoclusters morphology with size of ~210 nm and ~245 nm respectively. The characteristic absorption wavelength that occurs at 980 nm due to transition of energy levels {sup 2}F{sub 5/2} to {sup 2}F{sub 7/2} formore » Yb{sup 3+} rare earth ion in as prepared and calcined upconversion nanoparticle confirms the presence of Yb{sup 3+} by UV-Visible spectroscopy which can act as a sensitizer for photonic upconversion. Therefore the absorption at NIR region and emission spectrum at visible region suggests that NaYF{sub 4}:20%Yb,2%Er is suitable for upcoversion process, due to its optical property and chemical stability this material also be useful for bio imaging applications.« less

DNA-assisted upconversion nanoplatform for imaging-guided synergistic therapy and laser-switchable drug detoxification.

PubMed

Li, Luoyuan; Hao, Panlong; Wei, Peng; Fu, Limin; Ai, Xicheng; Zhang, Jianping; Zhou, Jing

2017-08-01

The side effects of chemotherapy bring significant physical and psychological suffering to patients. To solve this urgent medical problem, Yb 3+ and Er 3+ co-doped NaLuF 4 upconversion nanoparticles (UCNPs) were constructed for upconversion luminescence (UCL)-labeled diagnosis under 980 nm laser irradiation. The UCNPs were then modified layer by layer with polypyrrole and a special programming DNA segment as photothermal conversion agents and controllable drug carriers, respectively. The nanoplatform was successfully used for imaging-guided synergistic therapy (photothermal therapy and chemotherapy) at a safe power density (300 mW cm -2 ), and DNA-assisted detoxification at lower temperature in cancer cells when the laser off. The synergistic therapy of the nanoplatform achieved a higher therapeutic index (∼85%) than chemotherapy only (∼44%) and photothermal therapy only (∼25%) in vitro. In vivo experiments also suggested that the nanoplatform had a higher therapeutic effect and lower side effects. The toxicity study was also evaluated, indicating the nanoplatform is low toxic to living system. This multifunctional upconversion nanoplatform provided an innovative method for imaging-guided photothermal-chemotherapy and laser-switchable drug detoxification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Zirconia nanocrystals as submicron level biological label

NASA Astrophysics Data System (ADS)

Smits, K.; Liepins, J.; Gavare, M.; Patmalnieks, A.; Gruduls, A.; Jankovica, D.

2012-08-01

Inorganic nanocrystals are of increasing interest for their usage in biology and pharmacology research. Our interest was to justify ZrO2 nanocrystal usage as submicron level biological label in baker's yeast Saccharomyces cerevisia culture. For the first time (to our knowledge) images with sub micro up-conversion luminescent particles in biologic media were made. A set of undoped as well as Er and Yb doped ZrO2 samples at different concentrations were prepared by sol-gel method. The up-conversion luminescence for free standing and for nanocrystals with baker's yeast cells was studied and the differences in up-conversion luminescence spectra were analyzed. In vivo toxic effects of ZrO2 nanocrystals were tested by co-cultivation with baker's yeast.

Highly efficient green up-conversion luminescence of Nd3+-Yb3+-Ho3+ codoped fluorite-type nanocrystals in transparent glass ceramics

NASA Astrophysics Data System (ADS)

Qiu, Jianbei; Kawamoto, Yoji; Zhang, Junjie

2002-11-01

Oxyfluoride glasses were developed with composition 30SiO2[middle dot]15AlO1.5[middle dot]28PbF2[middle dot]22CdF2[middle dot](4.8-x)GdF3[middle dot]0.1NdF3[middle dot]0.1HoF3[middle dot]xYbF3 (x=0, 0.1, 0.2, 0.5, 1, 2, 3, 4, and 4.8) in mole percent. Powder x-ray diffraction analysis revealed that the heat treatments of the oxyfluoride glasses at 450 degC for 0.5 h cause the precipitation of Nd3+-Yb3+-Ho3+ codoped fluorite-type nanocrystals of about 16.3 nm in diameter in the glass matrix. These transparent glass ceramics exhibited very strong green up-conversion luminescence due to the Ho3+: (5F4, 5S2)[right arrow]5I8 transition under 800 nm excitation. The intensity of the green up-conversion luminescence in a 1 mol % YbF3-containing glass ceramic was found to be about 120 times stronger than that in the precursor oxyfluoride glass. The reason for the highly efficient Ho3+ up-conversion luminescence in the oxyfluoride glass ceramics is discussed. An up-conversion mechanism is also proposed.

Triple-functional core-shell structured upconversion luminescent nanoparticles covalently grafted with photosensitizer for luminescent, magnetic resonance imaging and photodynamic therapy in vitro

NASA Astrophysics Data System (ADS)

Qiao, Xiao-Fei; Zhou, Jia-Cai; Xiao, Jia-Wen; Wang, Ye-Fu; Sun, Ling-Dong; Yan, Chun-Hua

2012-07-01

Upconversion luminescent nanoparticles (UCNPs) have been widely used in many biochemical fields, due to their characteristic large anti-Stokes shifts, narrow emission bands, deep tissue penetration and minimal background interference. UCNPs-derived multifunctional materials that integrate the merits of UCNPs and other functional entities have also attracted extensive attention. Here in this paper we present a core-shell structured nanomaterial, namely, NaGdF4:Yb,Er@CaF2@SiO2-PS, which is multifunctional in the fields of photodynamic therapy (PDT), magnetic resonance imaging (MRI) and fluorescence/luminescence imaging. The NaGdF4:Yb,Er@CaF2 nanophosphors (10 nm in diameter) were prepared via sequential thermolysis, and mesoporous silica was coated as shell layer, in which photosensitizer (PS, hematoporphyrin and silicon phthalocyanine dihydroxide) was covalently grafted. The silica shell improved the dispersibility of hydrophobic PS molecules in aqueous environments, and the covalent linkage stably anchored the PS molecules in the silica shell. Under excitation at 980 nm, the as-fabricated nanomaterial gave luminescence bands at 550 nm and 660 nm. One luminescent peak could be used for fluorescence imaging and the other was suitable for the absorption of PS to generate singlet oxygen for killing cancer cells. The PDT performance was investigated using a singlet oxygen indicator, and was investigated in vitro in HeLa cells using a fluorescent probe. Meanwhile, the nanomaterial displayed low dark cytotoxicity and near-infrared (NIR) image in HeLa cells. Further, benefiting from the paramagnetic Gd3+ ions in the core, the nanomaterial could be used as a contrast agent for magnetic resonance imaging (MRI). Compared with the clinical commercial contrast agent Gd-DTPA, the as-fabricated nanomaterial showed a comparable longitudinal relaxivities value (r1) and similar imaging effect.Upconversion luminescent nanoparticles (UCNPs) have been widely used in many biochemical fields, due to their characteristic large anti-Stokes shifts, narrow emission bands, deep tissue penetration and minimal background interference. UCNPs-derived multifunctional materials that integrate the merits of UCNPs and other functional entities have also attracted extensive attention. Here in this paper we present a core-shell structured nanomaterial, namely, NaGdF4:Yb,Er@CaF2@SiO2-PS, which is multifunctional in the fields of photodynamic therapy (PDT), magnetic resonance imaging (MRI) and fluorescence/luminescence imaging. The NaGdF4:Yb,Er@CaF2 nanophosphors (10 nm in diameter) were prepared via sequential thermolysis, and mesoporous silica was coated as shell layer, in which photosensitizer (PS, hematoporphyrin and silicon phthalocyanine dihydroxide) was covalently grafted. The silica shell improved the dispersibility of hydrophobic PS molecules in aqueous environments, and the covalent linkage stably anchored the PS molecules in the silica shell. Under excitation at 980 nm, the as-fabricated nanomaterial gave luminescence bands at 550 nm and 660 nm. One luminescent peak could be used for fluorescence imaging and the other was suitable for the absorption of PS to generate singlet oxygen for killing cancer cells. The PDT performance was investigated using a singlet oxygen indicator, and was investigated in vitro in HeLa cells using a fluorescent probe. Meanwhile, the nanomaterial displayed low dark cytotoxicity and near-infrared (NIR) image in HeLa cells. Further, benefiting from the paramagnetic Gd3+ ions in the core, the nanomaterial could be used as a contrast agent for magnetic resonance imaging (MRI). Compared with the clinical commercial contrast agent Gd-DTPA, the as-fabricated nanomaterial showed a comparable longitudinal relaxivities value (r1) and similar imaging effect. Electronic supplementary information (ESI) available: More TEM, emission spectra, longitudinal and transverse relaxation times, t2-weighted MR images of the as-prepared nanomaterial, and confocal fluorescent images of HeLa cells. See DOI: 10.1039/c2nr30938f

Up-Conversion Y2O3:Yb(3+),Er(3+) Hollow Spherical Drug Carrier with Improved Degradability for Cancer Treatment.

PubMed

Ge, Kun; Zhang, Cuimiao; Sun, Wentong; Liu, Huifang; Jin, Yi; Li, Zhenhua; Liang, Xing-Jie; Jia, Guang; Zhang, Jinchao

2016-09-28

The rare earth hollow spheres with up-conversion luminescence properties have shown potential applications in drug delivery and bioimaging fields. However, there have been few reports for the degradation properties of rare earth oxide drug carriers. Herein, uniform and well-dispersed Y2O3:Yb(3+),Er(3+) hollow spheres (YOHSs) have been fabricated by a general Pechini sol-gel process with melamine formaldehyde colloidal spheres as template. The novel YOHSs with up-conversion luminescence has good drug loading amount and drug-release efficiency; moreover, it exhibits pH-responsive release patterns. In particular, the YOHSs sample exhibits low cytotoxicity and excellent degradable properties in acid buffer. After the sample was loaded with anticancer drug doxorubicin (DOX), the antitumor result in vitro indicates that YOHS-DOX might be effective in cancer treatment. The animal imaging test also reveals that the YOHSs drug carrier can be used as an outstanding luminescent probe for bioimaging in vivo application prospects. The results suggest that the degradable drug carrier with up-conversion luminescence may enhance the delivery efficiency of drugs and improve the cancer therapy in clinical applications.

Aptamer-Mediated Up-conversion Core/MOF Shell Nanocomposites for Targeted Drug Delivery and Cell Imaging

PubMed Central

Deng, Kerong; Hou, Zhiyao; Li, Xuejiao; Li, Chunxia; Zhang, Yuanxin; Deng, Xiaoran; Cheng, Ziyong; Lin, Jun

2015-01-01

Multifunctional nanocarriers for targeted bioimaging and drug delivery have attracted much attention in early diagnosis and therapy of cancer. In this work, we develop a novel aptamer-guided nanocarrier based on the mesoporous metal-organic framework (MOF) shell and up-conversion luminescent NaYF4:Yb3+/Er3+ nanoparticles (UCNPs) core for the first time to achieve these goals. These UCNPs, chosen as optical labels in biological assays and medical imaging, could emit strong green emission under 980 nm laser. The MOF structure based on iron (III) carboxylate materials [MIL-100 (Fe)] possesses high porosity and non-toxicity, which is of great value as nanocarriers for drug storage/delivery. As a unique nanoplatform, the hybrid inorganic-organic drug delivery vehicles show great promising for simultaneous targeted labeling and therapy of cancer cells. PMID:25597762

Neuroendocrine Tumor-Targeted Upconversion Nanoparticle-Based Micelles for Simultaneous NIR-Controlled Combination Chemotherapy and Photodynamic Therapy, and Fluorescence Imaging

PubMed Central

Chen, Guojun; Jaskula-Sztul, Renata; Esquibel, Corinne R.; Lou, Irene; Zheng, Qifeng; Dammalapati, Ajitha; Harrison, April; Eliceiri, Kevin W.; Tang, Weiping

2017-01-01

Although neuroendocrine tumors (NETs) are slow growing, they are frequently metastatic at the time of discovery and no longer amenable to curative surgery, emphasizing the need for the development of other treatments. In this study, multifunctional upconversion nanoparticle (UCNP)-based theranostic micelles are developed for NET-targeted and near-infrared (NIR)-controlled combination chemotherapy and photodynamic therapy (PDT), and bioimaging. The theranostic micelle is formed by individual UCNP functionalized with light-sensitive amphiphilic block copolymers poly(4,5-dimethoxy-2-nitrobenzyl methacrylate)-polyethylene glycol (PNBMA-PEG) and Rose Bengal (RB) photosensitizers. A hydrophobic anticancer drug, AB3, is loaded into the micelles. The NIR-activated UCNPs emit multiple luminescence bands, including UV, 540 nm, and 650 nm. The UV peaks overlap with the absorption peak of photocleavable hydrophobic PNBMA segments, triggering a rapid drug release due to the NIR-induced hydrophobic-to-hydrophilic transition of the micelle core and thus enabling NIR-controlled chemotherapy. RB molecules are activated via luminescence resonance energy transfer to generate 1O2 for NIR-induced PDT. Meanwhile, the 650 nm emission allows for efficient fluorescence imaging. KE108, a true pansomatostatin nonapeptide, as an NET-targeting ligand, drastically increases the tumoral uptake of the micelles. Intravenously injected AB3-loaded UCNP-based micelles conjugated with RB and KE108—enabling NET-targeted combination chemotherapy and PDT—induce the best antitumor efficacy. PMID:28989337

Intranuclear biophotonics by smart design of nuclear-targeting photo-/radio-sensitizers co-loaded upconversion nanoparticles.

PubMed

Fan, Wenpei; Shen, Bo; Bu, Wenbo; Zheng, Xiangpeng; He, Qianjun; Cui, Zhaowen; Ni, Dalong; Zhao, Kuaile; Zhang, Shengjian; Shi, Jianlin

2015-11-01

Biophotonic technology that uses light and ionizing radiation for positioned cancer therapy is a holy grail in the field of biomedicine because it can overcome the systemic toxicity and adverse side effects of conventional chemotherapy. However, the existing biophotonic techniques fail to achieve the satisfactory treatment efficacy, which remains a big challenge for clinical implementation. Herein, we develop a novel theranostic technique of "intranuclear biophotonics" by the smart design of a nuclear-targeting biophotonic system based on photo-/radio-sensitizers covalently co-loaded upconversion nanoparticles. These nuclear-targeting biophotonic agents can not only generate a great deal of multiple cytotoxic reactive oxygen species in the nucleus by making full use of NIR/X-ray irradiation, but also produce greatly enhanced intranuclear synergetic radio-/photodynamic therapeutic effects under the magnetic/luminescent bimodal imaging guidance, which may achieve the optimal efficacy in treating radio-resistant tumors. We anticipate that the highly effective intranuclear biophotonics will contribute significantly to the development of biophotonic techniques and open new perspectives for a variety of cancer theranostic applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multicolor Upconversion Nanoparticles for Protein Conjugation

PubMed Central

Wilhelm, Stefan; Hirsch, Thomas; Patterson, Wendy M.; Scheucher, Elisabeth; Mayr, Torsten; Wolfbeis, Otto S.

2013-01-01

We describe the preparation of monodisperse, lanthanide-doped hexagonal-phase NaYF4 upconverting luminescent nanoparticles for protein conjugation. Their core was coated with a silica shell which then was modified with a poly(ethylene glycol) spacer and N-hydroxysuccinimide ester groups. The nanoparticles were characterized by transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and dynamic light scattering. The N-hydroxysuccinimide ester functionalization renders them highly reactive towards amine nucleophiles (e.g., proteins). We show that such particles can be conjugated to proteins. The protein-reactive UCLNPs and their conjugates to streptavidin and bovine serum albumin display multicolor emissions upon 980-nm continuous wave laser excitation. Surface plasmon resonance studies were carried out to prove bioconjugation and to compare the affinity of the particles for proteins immobilized on a thin gold film. PMID:23606910

Formation Mechanism, Structural, and Upconversion Properties of Alkaline Rare-Earth Fluoride Nanocrystals Doped With Yb3+/Er3+ Ions.

PubMed

Grzyb, Tomasz; Przybylska, Dominika

2018-06-04

Ultrasmall (9-30 nm) Yb 3+ /Er 3+ -doped, upconverting alkaline rare-earth fluorides that are promising for future applications were synthesized by the microwave-assisted hydrothermal method. The formation mechanism was proposed, indicating the influence of the stability of metal ions complexes with ethylenediaminetetraacetic acid on the composition of the product and tendency to form M 2 REF 7 (M 0.67 RE 0.33 F 2.33 ) cubic compounds in the M-RE-F systems. Their physicochemical properties (structure, morphology, and spectroscopic properties) are compared and discussed. The obtained nanoparticles exhibited emission of light in the visible spectra under excitation by 976 nm laser radiation. Excitation and emission spectra, luminescence decays, laser energy dependencies, and upconversion quantum yields were measured to determine the spectroscopic properties of prepared materials. The Yb 3+ /Er 3+ pair of ions used as dopants was responsible for an intense yellowish-green emission. The upconversion quantum yields determined for the first time for M 2 REF 7 -based materials were 0.0192 ± 0.001% and 0.0176 ± 0.001% for Sr 2 LuF 7 :Yb 3+ ,Er 3+ and Ba 2 LuF 7 :Yb 3+ ,Er 3+ respectively, the two best emitting samples. These results indicated the prepared materials are good and promising alternatives for the most studied NaYF 4 :Yb 3+ ,Er 3+ nanoparticles.

Infrared spectroscopy and upconversion luminescence behaviour of erbium doped yttrium (III) oxide phosphor

NASA Astrophysics Data System (ADS)

Dubey, Vikas; Tiwari, Ratnesh; Tamrakar, Raunak Kumar; Rathore, Gajendra Singh; Sharma, Chitrakant; Tiwari, Neha

2014-11-01

The paper reports upconversion luminescence behaviour and infra-red spectroscopic pattern of erbium doped yttrium (III) oxide phosphor. Sample was synthesized by solid state reaction method with variable concentration or erbium (0.5-2.5 mol%). The conventional solid state method is suitable for large scale production and eco-friendly method. The prepared sample was characterized by X-ray diffraction (XRD) technique. From structural analysis by XRD technique shows cubic structure of prepared sample with variable concentration of erbium and no impurity phase were found when increase the concentration of Er3+. Particle size was calculated by Scherer's formula and it varies from 67 nm to 120 nm. The surface morphology of prepared phosphor was determined by field emission gun scanning electron microscopy (FEGSEM) technique. The surface morphology of the sample shows good connectivity with grains as well as some agglomerates formation occurs in sample. The functional group analysis was done by Fourier transform infra-red technique (FTIR) analysis which confirm the formation of Y2O3:Er3+ phosphor was prepared. The results indicated that the Y2O3:Er3+ phosphors might have high upconversion efficiency because of their low vibrational energy. Under 980 nm laser excitation sample shows intense green emission at 555 nm and orange emission at 590 nm wavelength. For green emission transition occurs 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 for upconversion emissions. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The near infrared luminescence spectra was recorded. The upconversion luminescence intensity increase with increasing the concentration or erbium up to 2 mol% after that luminescence intensity decreases due to concentration quenching occurs. Spectrophotometric determinations of peaks are evaluated by Commission Internationale de I'Eclairage (CIE) technique. From CIE technique the dominant peak of from PL spectra shows intense green emission so the prepared phosphor is may be useful for green light emitting diode (GLED) application.

Magnetic upconverting fluorescent NaGdF4:Ln3+ and iron-oxide@NaGdF4:Ln3+ nanoparticles

NASA Astrophysics Data System (ADS)

Shrivastava, Navadeep; Rocha, Uéslen; Muraca, Diego; Jacinto, Carlos; Moreno, Sergio; Vargas, J. M.; Sharma, S. K.

2018-05-01

Microwave assisted solvothermal method has been employed to synthesize multifunctional upconverting β-NaGdF4:Ln3+ and magnetic-upconverting Fe3O4/γ-Fe2O3@NaGdF4:Ln3+ (Ln = Yb and Er) nanoparticles. The powder x-ray diffraction data confirms the hexagonal structure of NaGdF4:Ln3+ and high resolution transmission electron microscopy shows the formation of rod shaped NaGdF4:Ln3+ (˜ 20 nm) and ovoid shaped Fe3O4/γ-Fe2O3@NaGdF4:Ln3+ (˜ 15 nm) nanoparticles. The magnetic hysteresis at 300 K for β-NaGdF4:Ln3+ demonstrates paramagnetic features, whereas iron-oxide@β-NaGdF4:Ln3+ exhibits superparamagnetic behavior along with a linear component at large applied field due to paramagnetic NaGdF4 matrix. Both nanoparticle samples provide an excellent green emitting [(2H11/2, 4S3/2)→4I15/2 (˜ 540 nm)] upconversion luminescence emission under excitation at 980 nm. The energy migration between Yb and Er in NaGdF4 matrix has been explored from 300-800 nm. Intensity variation of blue, green and red lines and the observed luminescence quenching due to the presence of Fe3O4/γ-Fe2O3 in the composite has been proposed. These kinds of materials contain magnetic and luminescence characteristics into single nanoparticle open new possibility for bioimaging applications.

Yb3+/Ho3+ Co-Doped Apatite Upconversion Nanoparticles to Distinguish Implanted Material from Bone Tissue.

PubMed

Li, Xiyu; Chen, Haifeng

2016-10-07

The exploration of bone reconstruction with time requires the combination of a biological method and a chemical technique. Lanthanide Yb 3+ and Ho 3+ co-doped fluorapatite (FA:Yb 3+ /Ho 3+ ) and hydroxyapatite (HA:Yb 3+ /Ho 3+ ) particles with varying dopant concentrations were prepared by hydrothermal synthesis and thermal activation. Controllable green and red upconversion emissions were generated under 980 nm near-infrared excitation; the FA:Yb 3+ /Ho 3+ particles resulted in superior green luminescence, while HA:Yb 3+ /Ho 3+ dominated in red emission. The difference in the green and red emission behavior was dependent on the lattice structure and composition. Two possible lattice models were proposed for Yb 3+ /Ho 3+ co-doped HA and FA along the hydroxyl channel and fluorine channel of the apatite crystal structure. We first reported the use of the upconversion apatite particles to clearly distinguish implanted material from bone tissue on stained histological sections of harvested in vivo samples. The superposition of the tissue image and material image is a creative method to show the material-tissue distribution and interrelation. The upconversion apatite particles and image superposition method provide a novel strategy for long-term discriminable fluorescence tracking of implanted material or scaffold during bone regeneration.

Photo-crosslinked hyaluronic acid coated upconverting nanoparticles

NASA Astrophysics Data System (ADS)

Mrazek, Jiri; Kettou, Sofiane; Matuska, Vit; Svozil, Vit; Huerta-Angeles, Gloria; Pospisilova, Martina; Nesporova, Kristina; Velebny, Vladimir

2017-02-01

Hyaluronic acid (HA)-coated inorganic nanoparticles display enhanced interaction with the CD44 receptors which are overexpressed in many types of cancer cells. Here, we describe a modification of core-shell β-NaY0.80Yb0.18Er0.02F4@NaYF4 nanoparticles (UCNP) by HA derivative bearing photo-reactive groups. UCNP capped with oleic acid were firstly transferred to aqueous phase by an improved protocol using hydrochloric acid or lactic acid treatment. Subsequently, HA bearing furanacryloyl moieties (HA-FU) was adsorbed on the nanoparticle surface and crosslinked by UV irradiation. The crosslinking resulted in stable HA coating, and no polymer desorption was observed. As-prepared UCNP@HA-FU show a hydrodynamic diameter of about 180 nm and are colloidally stable in water and cell culture media. The cellular uptake by normal human fibroblasts and MDA MB-231 cancer cell line was investigated by upconversion luminescence imaging.

Down- and up-conversion luminescent carbon dot fluid: inkjet printing and gel glass fabrication.

PubMed

Wang, Fu; Xie, Zheng; Zhang, Bing; Liu, Yun; Yang, Wendong; Liu, Chun-yan

2014-04-07

Room temperature liquid-like nanoparticles have emerged as an exciting new research and development area, because their properties could be tailored over a broad range by manipulating geometric and chemical characteristics of the inorganic core and organic canopy. However, related applications are rarely reported due to the multi-step synthesis process and potential toxicity of cadmium based nanomaterials. In this study, we prepared inexpensive and eco-friendly carbon dot fluid by the direct thermal decomposition method. The carbon dot fluid can be excited from UV to near infrared light, and can be prepared as highly concentrated luminescent ink or incorporated into sol-gel derived organically modified silicate glass, suggesting that it has great application potential in the field of printable electronics, solid state lighting and so on.

Multicolor tunability and upconversion enhancement of fluoride nanoparticles by oxygen dopant

NASA Astrophysics Data System (ADS)

Niu, Wenbin; Wu, Suli; Zhang, Shufen; Su, Liap Tat; Tok, Alfred Iing Yoong

2013-08-01

The ability to manipulate the upconversion luminescence of lanthanide-ion doped fluoride upconversion nanoparticles (UCNPs) is particularly important and highly desired due to their wide applications in color displays, multiplexing bioassays and multicolor imaging. Here, we developed a strategy for simultaneously tuning color output and enhancing upconversion emission of Yb/Er doped fluoride UCNPs, based on adjusting the oxygen doping level. The synthesis of multicolored multifunctional NaGdF4:Yb,Er UCNPs was used as the model host system to demonstrate this protocol. Ammonium nitrate (NH4NO3) was used as the oxygen source and added into the reaction system at the beginning stage of nucleation and growth process of fluoride UCNPs, which facilitates the formation of enough oxygen atoms and the diffusion of these into the fluoride host matrix. The results revealed that multicolour output and upconversion enhancement mainly resulted from the variation of phonon energy and crystal field symmetry of the host lattice, respectively. This strategy can be further expanded to other fluoride host matrices. As an example of an application, multicolored UCNPs were used as a color converter in light emitting diodes, which can effectively convert near-infrared light into visible light. It is expected that these multicolored UCNPs will be promising for applications in multiplexing biodetection, bioimaging (optical and magnetic resonance imaging) and other optical technologies, and the present method for the control of O2- doping may also be used in other functional nanomaterials.The ability to manipulate the upconversion luminescence of lanthanide-ion doped fluoride upconversion nanoparticles (UCNPs) is particularly important and highly desired due to their wide applications in color displays, multiplexing bioassays and multicolor imaging. Here, we developed a strategy for simultaneously tuning color output and enhancing upconversion emission of Yb/Er doped fluoride UCNPs, based on adjusting the oxygen doping level. The synthesis of multicolored multifunctional NaGdF4:Yb,Er UCNPs was used as the model host system to demonstrate this protocol. Ammonium nitrate (NH4NO3) was used as the oxygen source and added into the reaction system at the beginning stage of nucleation and growth process of fluoride UCNPs, which facilitates the formation of enough oxygen atoms and the diffusion of these into the fluoride host matrix. The results revealed that multicolour output and upconversion enhancement mainly resulted from the variation of phonon energy and crystal field symmetry of the host lattice, respectively. This strategy can be further expanded to other fluoride host matrices. As an example of an application, multicolored UCNPs were used as a color converter in light emitting diodes, which can effectively convert near-infrared light into visible light. It is expected that these multicolored UCNPs will be promising for applications in multiplexing biodetection, bioimaging (optical and magnetic resonance imaging) and other optical technologies, and the present method for the control of O2- doping may also be used in other functional nanomaterials. Electronic supplementary information (ESI) available: Upconversion spectra of NaYF4:Yb,Er UCNPs prepared with various oxygen sources (trimethylamine N-oxide and ammonium carbonate, Fig. S1) and different addition temperatures of NH4NO3 (Fig. S2), enlarged XRD patterns (Fig. S3), the intensity ratios of green to red emissions of NaGdF4:Yb,Er UCNPs prepared with various amounts of NH4NO3 (Fig. S4), power dependence of upconversion spectra of NaGdF4:Yb,Er UCNPs prepared at 300 °C for 1 h (Fig. S5), upconversion spectra of the product after further reaction between as-prepared NaYF4:Yb,Er and 50 mg of NH4NO3 at 300 °C for 1 h (Fig. S6), XRD patterns of NaYF4:Yb,Er and NaLuF4:Yb,Er UCNPs prepared with various amounts of NH4NO3 (Fig. S7 and S8), the corresponding magnetization curves of NaGdF4:Yb,Er UCNPs (Fig. S9). See DOI: 10.1039/c3nr01612a

Self-Assembled Upconversion Nanoparticle Clusters for NIR-controlled Drug Release and Synergistic Therapy after Conjugation with Gold Nanoparticles.

PubMed

Cai, Huijuan; Shen, Tingting; Kirillov, Alexander M; Zhang, Yu; Shan, Changfu; Li, Xiang; Liu, Weisheng; Tang, Yu

2017-05-01

Fabricated three-dimensional (3D) upconversion nanoclusters (abbreviated as EBSUCNPs) are obtained via an emulsion-based bottom-up self-assembly of NaGdF 4 :Yb/Er@NaGdF 4 nanoparticles (abbreviated as UCNPs), which comprise a NaGdF 4 :Yb/Er core and a NaGdF 4 shell. The EBSUCNPs were then coated with a thin mesoporous amino-functionalized SiO 2 shell (resulting in EBSUCNPs@SiO 2 precursor) and further conjugated with gold nanoparticles to give the novel EBSUCNPs@SiO 2 @Au material. Finally, EBSUCNPs@SiO 2 @Au was applied as a biocompatible and efficient drug carrier for doxorubicin (DOX), thus giving rise to a multifunctional EBSUCNPs@SiO 2 -DOX@Au nanocomposite. This final material, EBSUCNPs@SiO 2 -DOX@Au, and the precursor nanoparticles, EBSUCNPs@SiO 2 @Au, were both fully characterized and their luminescence was investigated in detail. In addition, the drug release properties and photothermal effects of EBSUCNPs@SiO 2 -DOX@Au were also discussed. Interestingly, when under NIR irradiation, an increasing DOX release was achieved owing to the thermal effect of the Au NPs after absorbing the green light from the upconversion nanoclusters based on the fluorescence resonance energy transfer (FRET) effect. Thus, a near-infrared (NIR)-controlled "on-off" pattern of drug release behavior can be achieved. Moreover, compared with a single therapy method, the assembled nanocomposites exhibit a good synergistic therapy against cancer cells that combines chemotherapy with photothermal therapy. In addition, the in vitro fluorescence microscopy images of EBSUCNPs@SiO 2 -DOX@Au show a higher enhancement in the red region due to the loading of DOX molecules with respect to EBSUCNPs@SiO 2 @Au. Therefore, this novel multifunctional 3D cluster architecture can be used in the biomedical field after modification and may pave a new way in other application areas of UCNPs clusters.

Interactions of DNA coated upconversion nanoparticles with 2D materials

NASA Astrophysics Data System (ADS)

Giust, Davide; Lucío, María. Isabel; Muskens, Otto L.; Kanaras, Antonios G.

2018-02-01

In this work we investigated the nature of quenching between different types of 2D materials (WS2, MoS2 and graphene oxide) and oligonucleotide coated-upconversion nanoparticles. This study contributes towards the efficient design of biosensors based on 2D materials and DNA-coated upconversion nanoparticles.

One-step hydrothermal synthesis of carboxyl-functionalized upconversion phosphors for bioapplications.

PubMed

Yang, Jianping; Shen, Dengke; Li, Xiaomin; Li, Wei; Fang, Yin; Wei, Yong; Yao, Chi; Tu, Bo; Zhang, Fan; Zhao, Dongyuan

2012-10-22

In this paper, we report a facile one-step hydrothermal method to synthesize phase-, size-, and shape-controlled carboxyl-functionalized rare-earth fluorescence upconversion phosphors by using a small-molecule binary acid, such as malonic acid, oxalic acid, succinic acid, or tartaric acid as capping agent. The crystals, from nano- to microstructures with diverse shapes that include nanospheres, microrods, hexagonal prisms, microtubes, microdisks, polygonal columns, and hexagonal tablets, can be obtained with different reaction times, reaction temperatures, molar ratios of capping agent to sodium hydroxide, and by varying the binary acids. Fourier transform infrared, thermogravimetric analysis, and upconversion luminescence spectra measurements indicate that the synthesized NaYF(4):Yb/Er products with hydrophilic carboxyl-functionalized surface offer efficient upconversion luminescent performance. Furthermore, the antibody/secondary antibody conjugation can be realized by the carboxyl-functionalized surfaces of the upconversion phosphors, thus indicating the potential bioapplications of these kinds of materials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced red emission of 808 nm excited upconversion nanoparticles by optimizing the composition of shell for efficient generation of singlet oxygen

NASA Astrophysics Data System (ADS)

Liu, Jinxue; Zhang, Tingbin; Song, Xiaoyan; Xing, Jinfeng

2018-01-01

With the aim to enhance the upconversion luminescence (UCL) intensity, much attention was paid to reduce the energy-back transfer from Er3+ ions to Nd3+ ions by constructing various kinds of multilayer upconversion nanoparticles (UCNPs). However, the energy-back transfer was difficult to be completely eliminated. Also, the thick shell of multilayer UCNPs is not favourable for effective Förster resonance energy transfer (FRET) in photodynamic therapy (PDT) system. Herein, an effective and facile method was applied to prepare UCNPs by optimizing the composition to largely enhance the red emission (at 660 nm) for efficient generation of singlet oxygen (1O2). In detail, the concentrations of Nd3+ ions and Yb3+ ions doped in the sensitizing shell were systematically researched to balance the energy back-transfer and the light harvest ability. The optimal emission and a relatively high Red/Green (R/G) ratio of NaYF4:Yb,Er,Nd@NaYF4:Yb0.1Nd0.2 UCNPs were obtained simultaneously. Furthermore, the emission under 980 nm excitation demonstrated the energy back-transfer from Er3+ to Yb3+ ions was also notable which was largely ignored previously. Then, UCNPs were encapsulated into mesoporous silica shell, and the photosensitizer Chlorin e6 (Ce6) was covalently conjugated to form a non-leaking nanoplatform. The efficiency of 1O2 generation obviously increased with the enhanced emission of UCNPs.

Sensing Using Rare-Earth-Doped Upconversion Nanoparticles

PubMed Central

Hao, Shuwei; Chen, Guanying; Yang, Chunhui

2013-01-01

Optical sensing plays an important role in theranostics due to its capability to detect hint biochemical entities or molecular targets as well as to precisely monitor specific fundamental psychological processes. Rare-earth (RE) doped upconversion nanoparticles (UCNPs) are promising for these endeavors due to their unique frequency converting capability; they emit efficient and sharp visible or ultraviolet (UV) luminescence via use of ladder-like energy levels of RE ions when excited at near infrared (NIR) light that are silent to tissues. These features allow not only a high penetration depth in biological tissues but also a high detection sensitivity. Indeed, the energy transfer between UCNPs and biomolecular or chemical indicators provide opportunities for high-sensitive bio- and chemical-sensing. A temperature-sensitive change of the intensity ratio between two close UC bands promises them for use in temperature mapping of a single living cell. In this work, we review recent investigations on using UCNPs for the detection of biomolecules (avidin, ATP, etc.), ions (cyanide, mecury, etc.), small gas molecules (oxygen, carbon dioxide, ammonia, etc.), as well as for in vitro temperature sensing. We also briefly summarize chemical methods in synthesizing UCNPs of high efficiency that are important for the detection limit. PMID:23650480

Upconversion-pumped luminescence efficiency of rare-earth-doped hosts sensitized with trivalent ytterbium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Page, R.H.; Schaffers, K.I.; Waide, P.A.

We discuss the upconversion luminescence efficiencies of phosphors that generate red, green, and blue light. The phosphors studied are single crystals and powders co-doped with Er{sup 3+} and Yb{sup 3+}, and with Tm{sup 3+} and Yb{sup 3+}. The Yb ions are pumped near 980 nm; transfers of two or three quanta to the co-doped rare earth ion generate visible luminescence. The main contribution embodied in this work is the quantitative measurement of this upconversion efficiency, based on the use of a calibrated integrating sphere, determination of the fraction of pump light absorbed, and careful control of the pump laser beammore » profile. The green phosphors are the most efficient, yielding efficiency values as high as 4 %, with the red and blue materials giving 1 - 2 %. Saturation was observed in all cases, suggesting that populations of upconversion steps of the ions are maximized at higher power. Quasi-CW modeling of the intensity- dependent upconversion efficiency was attempted; input data included level lifetimes, transition cross sections, and cross-relaxation rate coefficients. The saturation of the Yb,Er:fluoride media is explained as the pumping of Er{sup 3+} ions into a bottleneck (long-lived state)- the {sup 4}I{sub 13/2} metastable level, making them unavailable for further excitation transfer. 32 refs., 5 figs., 3 tabs.« less

Nanocrystals feel the heat

NASA Astrophysics Data System (ADS)

Liang, Liangliang; Liu, Xiaogang

2018-03-01

Phosphors often suffer luminescence quenching at elevated temperatures. Now, thermal quenching can be combated with surface phonon-assisted energy transfer, enabling the luminescence of ultrasmall upconversion nanophosphors to be dramatically enhanced.

Luminescence studies and infrared emission of erbium-doped calcium zirconate phosphor.

PubMed

Tiwari, Neha; Dubey, Vikas

2016-05-01

The near-infrared-to-visible upconversion luminescence behaviour of Er(3+)-doped CaZrO3 phosphor is discussed in this manuscript. The phosphor was prepared by a combustion synthesis technique that is suitable for less-time-taking techniques for nanophosphors. The starting materials used for sample preparation were Ca(NO3)2.4H2O, Zr(NO3)4 and Er(NO3)2, and urea was used as a fuel. The prepared sample was characterized by X-ray diffraction (XRD). The surface morphology of prepared phosphor was determined by field emission gun scanning electron microscopy (FEGSEM). The functional group analysis was determined by Fourier transform infrared (FTIR) spectroscopy. All prepared phosphors with variable Er(3+) concentrations (0.5-2.5 mol%) were studied by photoluminescence analysis. It was found that the excitation spectra of the prepared phosphor showed a sharp excitation peak centred at 980 nm. The emission spectra with variable Er(3+) concentrations showed strong peaks in the 555 nm and 567 nm range, with a dominant peak at 555 nm due to the ((2)H(11/2),(4)S(3/2)) transition and a weaker transition at 567 nm associated with 527 nm. Spectrophotometric determination of the peak was evaluated by the Commission Internationale de I'Eclairage (CIE) method These upconverted emissions were attributed to a two-photon process. The excitation wavelength dependence of the upconverted luminescence, together with its time evolution after infrared pulsed excitation, suggested that energy transfer upconversion processes were responsible for the upconversion luminescence. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer processes were discussed as possible upconversion mechanisms. The cross-relaxation process in Er(3+) was also investigated. Copyright © 2015 John Wiley & Sons, Ltd.

Labeling of HeLa cells using ZrO2:Yb3+-Er3+ nanoparticles with upconversion emission

NASA Astrophysics Data System (ADS)

Ceja-Fdez, Andrea; López-Luke, Tzarara; Oliva, Jorge; Vivero-Escoto, Juan; Gonzalez-Yebra, Ana Lilia; Rojas, Ruben A. Rodriguez; Martínez-Pérez, Andrea; de la Rosa, Elder

2015-04-01

This work reports the synthesis, structural characterization, and optical properties of ZrO2:Yb3+-Er3+ (2-1 mol%) nanocrystals. The nanoparticles were coated with 3-aminopropyl triethoxysilane (APTES) and further modified with biomolecules, such as Biotin-Anti-rabbit (mouse IgG) and rabbit antibody-AntiKi-67, through a conjugation method. The conjugation was successfully confirmed by Fourier transform infrared, zeta potential, and dynamic light scattering. The internalization of the conjugated nanoparticles in human cervical cancer (HeLa) cells was followed by two-photon confocal microscopy. The ZrO2:Yb3+-Er3+ nanocrystals exhibited strong red emission under 970-nm excitation. Moreover, the luminescence change due to the addition of APTES molecules and biomolecules on the nanocrystals was also studied. These results demonstrate that ZrO2:Yb3+-Er3+ nanocrystals can be successfully functionalized with biomolecules to develop platforms for biolabeling and bioimaging.

Aptamer biosensor for Salmonella typhimurium detection based on luminescence energy transfer from Mn2 +-doped NaYF4:Yb, Tm upconverting nanoparticles to gold nanorods

NASA Astrophysics Data System (ADS)

Cheng, Keyi; Zhang, Jianguo; Zhang, Liping; Wang, Lun; Chen, Hongqi

2017-01-01

A highly sensitive luminescent bioassay for the detection of Salmonella typhimurium was fabricated using Mn2 +-doped NaYF4:Yb,Tm upconversion nanoparticles (UCNPs) as the donor and gold nanorods (Au NRs) as the acceptor and utilizing an energy transfer (LET) system. Mn2 +-doped NaYF4:Yb,Tm UCNPs with a strong emission peak at 807 nm were obtained by changing the doped ion ratio. Carboxyl-terminated Mn2 +-doped NaYF4:Yb,Tm UCNPs were coupled with S. typhimurium aptamers, which were employed to capture and concentrate S. typhimurium. The electrostatic interactions shorten the distance between the negatively charged donor and the positively charged acceptor, which results in luminescence quenching. The added S. typhimurium leads to the restoration of luminescence due to the formation of UCNPs-aptamers-S. typhimurium, which repels the UCNPs-aptamers from the Au NRs. The LET system does not occur because of the nonexistence of the luminescence emission band of Mn2 +-doped NaYF4:Yb,Tm UCNPs, which had large spectral overlap with the absorption band of Au NRs. Under optimal conditions, the linear range of detecting S. typhimurium was 12 to 5 × 105 cfu/mL (R = 0.99). The limit of detection for S. typhimurium was as low as 11 cfu/mL in an aqueous buffer. The measurement of S. typhimurium in milk samples was satisfied in accordance with the plate-counting method, suggesting that the proposed method was of practical value in the application of food security.

Dual-color upconversion fluorescence and aptamer-functionalized magnetic nanoparticles-based bioassay for the simultaneous detection of Salmonella Typhimurium and Staphylococcus aureus.

PubMed

Duan, Nuo; Wu, Shijia; Zhu, Changqing; Ma, Xiaoyuan; Wang, Zhouping; Yu, Ye; Jiang, Yuan

2012-04-20

A sensitive luminescent bioassay for the simultaneous detection of Salmonella Typhimurium and Staphylococcus aureus was developed using aptamer-conjugated magnetic nanoparticles (MNPs) for both recognition and concentration elements and using upconversion nanoparticles (UCNPs) as highly sensitive dual-color labels. The bioassay system was fabricated by immobilizing aptamer 1 and aptamer 2 onto the surface of MNPs, which were employed to capture and concentrate S. Typhimurium and S. aureus. NaY(0.78)F(4):Yb(0.2),Tm(0.02) UCNPs modified aptamer 1 and NaY(0.28)F(4):Yb(0.70),Er(0.02) UCNPs modified aptamer 2 further were bond onto the captured bacteria surface to form sandwich-type complexes. Under optimal conditions, the correlation between the concentration of S. Typhimurium and the luminescent signal was found to be linear within the range of 10(1)-10(5) cfu mL(-1) (R(2)=0.9964), and the signal was in the range of 10(1)-10(5) cfu mL(-1) (R(2)=0.9936) for S. aureus. The limits of detection of the developed method were found to be 5 and 8 cfu mL(-1) for S. Typhimurium and S. aureus, respectively. The ability of the bioassay to detect S. Typhimurium and S. aureus in real water samples was also investigated, and the results were compared to the experimental results from the plate-counting methods. Improved by the magnetic separation and concentration effect of MNPs, the high sensitivity of UCNPs, and the different emission lines of Yb/Er- and Yb/Tm-doped NaYF(4) UCNPs excited by a 980 nm laser, the present method performs with both high sensitivity and selectivity for the two different types of bacteria. Copyright © 2012 Elsevier B.V. All rights reserved.

Lanthanum fluoride upconverting nanoparticles for photo-biomodulation of cell function

NASA Astrophysics Data System (ADS)

Tek, Sumeyra; Vincent, Brandy K.; Mimun, L. Christopher; Tran, Ashley N.; Shrestha, Binita; Tang, Liang; Nash, Kelly L.

2017-02-01

Inorganic fluorescent nanoprobes have been widely used as passive agents for intracellular imaging for decades. An emerging field of research is the development of these contrast agents and using them actively in a way that they respond to external stimulation by inducing photo-chemical, thermal or mechanical actions that enable control and modulation over cell function. To achieve such control, methods which are remote, non-invasive and with low-thermal means of stimulation is preferable. Among a large variety of candidates, lanthanide doped upconverting nanoparticles (UCNPs) are one of the most interesting class of fluorescent materials. Non-scattering, low energy near infrared (NIR) light can be used for excitation of UCNPs as on-demand light sources resulting in emission peaks throughout the near-UV and visible wavelengths. Towards this goal, we developed nano-size, hydrophilic, non-toxic and biocompatible core-shell nanoparticles with enhanced upconversion intensity for photo-biomodulation studies. Under this approach, un-doped LaF3 (inert) shell and Yb3+ doped LaF3 (active) shell are grown on core LaF3:20% Yb, 2% Tm upconverting nanoparticles for enhanced luminescence for the first time with rapid microwave-assisted synthesis method that employs Polyvinylpyrrolidone (PVP) as biocompatible surfactant. The as-synthesized high efficiency UCNPs are analyzed through XRD, TEM, HRTEM, and Photoluminescence spectrum that is acquired under 980 nm laser excitation. Confocal microscopy is used to visualize nanoparticles in cells. The cellular response to NIR irradiation and upconverted light are visualized by luminescence microscopy.

Construction of Hierarchical Polymer Brushes on Upconversion Nanoparticles via NIR-Light-Initiated RAFT Polymerization.

PubMed

Xie, Zhongxi; Deng, Xiaoran; Liu, Bei; Huang, Shanshan; Ma, Pingan; Hou, Zhiyao; Cheng, Ziyong; Lin, Jun; Luan, Shifang

2017-09-13

Photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization generally adopts high-energy ultraviolet (UV) or blue light. In combination with photoredox catalyst, the excitation light wavelength was extended to the visible and even near-infrared (NIR) region for photoinduced electron transfer RAFT polymerization. In this report, we introduce for the first time a surface NIR-light-initiated RAFT polymerization on upconversion nanoparticles (UCNPs) without adding any photocatalyst and construct a functional inorganic core/polymer shell nanohybrid for application in cancer theranostics. The multilayer core-shell UCNPs (NaYF 4 :Yb/Tm@NaYbF 4 :Gd@NaNdF 4 :Yb@NaYF 4 ), with surface anchorings of chain transfer agents, can serve as efficient NIR-to-UV light transducers for initiating the RAFT polymerization. A hierarchical double block copolymer brush, consisting of poly(acrylic acid) (PAA) and poly(oligo(ethylene oxide)methacrylate-co-2-(2-methoxy-ethoxy)ethyl methacrylate) (PEG for short), was grafted from the surface in sequence. The targeting arginine-glycine-aspartic (RGD) peptide was modified at the end of the copolymer through the trithiolcarbonate end group. After loading of doxorubicin, the UCNPs@PAA-b-PEG-RGD exhibited an enhanced U87MG cancer cell uptake efficiency and cytotoxicity. Besides, the unique upconversion luminescence of the nanohybrids was used for the autofluoresence-free cell imaging and labeling. Therefore, our strategy verified that UCNPs could efficiently activate RAFT polymerization by NIR photoirradiation and construct the complex nanohybrids, exhibiting prospective biomedical applications due to the low phototoxicity and deep penetration of NIR light.

Highly intensified upconversion luminescence of Ca(2+) -doped Yb/Er:NaGdF(4) nanocrystals prepared by a solvothermal route.

PubMed

Lei, Lei; Chen, Daqin; Xu, Ju; Zhang, Rui; Wang, Yuansheng

2014-03-01

Upon introducing Ca(2+) dopants into the grain lattices by substituting Gd(3+) ions, irregular Yb/Er:NaGdF4 nanocrystals prepared through a simple solvothermal route convert into highly uniform nanorods. Meanwhile, their upconversion luminescence intensifies by about 200 times, probably due to a modification of the crystal structure of NaGdF4 and an improvement in the crystallinity of the nanophase. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controlling upconversion nanocrystals for emerging applications

NASA Astrophysics Data System (ADS)

Zhou, Bo; Shi, Bingyang; Jin, Dayong; Liu, Xiaogang

2015-11-01

Lanthanide-doped upconversion nanocrystals enable anti-Stokes emission with pump intensities several orders of magnitude lower than required by conventional nonlinear optical techniques. Their exceptional properties, namely large anti-Stokes shifts, sharp emission spectra and long excited-state lifetimes, have led to a diversity of applications. Here, we review upconversion nanocrystals from the perspective of fundamental concepts and examine the technical challenges in relation to emission colour tuning and luminescence enhancement. In particular, we highlight the advances in functionalization strategies that enable the broad utility of upconversion nanocrystals for multimodal imaging, cancer therapy, volumetric displays and photonics.

Upconversion luminescence in Er3+ doped and Er3+/Yb3+ codoped zirconia and hafnia nanocrystals excited at 980 nm

NASA Astrophysics Data System (ADS)

Gómez, Luis A.; Menezes, Leonardo de S.; de Araújo, Cid B.; Gonçalves, Rogeria R.; Ribeiro, Sidney J. L.; Messaddeq, Younes

2010-06-01

Frequency upconversion (UC) luminescence in nanocrystalline zirconia (ZrO2) and hafnia (HfO2) doped with Er3+ and Yb3+ was studied under continuous-wave excitation at 980 nm. Samples of ZrO2:Er3+, ZrO2:Er3+/Yb3+, and HfO2:Er3+/Yb3+ were prepared by the sol-gel technique and characterized using x-ray diffraction and electron microscopy. A study of the infrared-to-green and infrared-to-red UC processes was performed including the analysis of the spectral and the temporal behavior. The mechanisms contributing to the UC luminescence were identified as excited state absorption and energy transfer among rare-earth ions.

Latent fingermark detection for NaYF4:Er3+/Yb3+ upconversion phosphor synthesized by thermal decomposition route

NASA Astrophysics Data System (ADS)

Maurya, S. K.; Tiwari, S. P.; Kumar, A.; Kumar, K.

2018-04-01

The synthesis and spectroscopy of the upconverting nanoparticles, cubic NaYF4:Er3+/Yb3+ phosphor is developed for latent fingermark detection. The cubic phase of NaYF4: Er3+/Yb3+ phosphor is synthesized by thermal decomposition method using trifluoroacetate precursor with coordinating ligand octadecene and oleic acid in a mixture of technical grade. The synthesized samples showed intense green emission using 976 nm diode laser as an excitation source. Because of excellent property of luminescence in green regime the sample is used to detect the latent fingermark on a porous glass surface.

Recent Advances in Upconversion Nanoparticles-Based Multifunctional Nanocomposites for Combined Cancer Therapy.

PubMed

Tian, Gan; Zhang, Xiao; Gu, Zhanjun; Zhao, Yuliang

2015-12-16

Lanthanide-doped upconversion nanoparticles (UCNPs) have the ability to generate ultraviolet or visible emissions under continuous-wave near-infrared (NIR) excitation. Utilizing this special luminescence property, UCNPs are approved as a new generation of contrast agents in optical imaging with deep tissue-penetration ability and high signal-to-noise ratio. The integration of UCNPs with other functional moieties can endow them with highly enriched functionalities for imaging-guided cancer therapy, which makes composites based on UCNPs emerge as a new class of theranostic agents in biomedicine. Here, recent progress in combined cancer therapy using functional nanocomposites based on UCNPs is reviewed. Combined therapy referring to the co-delivery of two or more therapeutic agents or a combination of different treatments is becoming more popular in clinical treatment of cancer because it generates synergistic anti-cancer effects, reduces individual drug-related toxicity and suppresses multi-drug resistance through different mechanisms of action. Here, the recent advances of combined therapy contributed by UCNPs-based nanocomposites on two main branches are reviewed: i) photodynamic therapy and ii) chemotherapy, which are the two most widely adopted therapies of UCNPs-based composites. The future prospects and challenges in this emerging field will be also discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermal, optical and vibrational studies of tyrosine doped LaF3:Ce nanoparticles for bioimaging and biotagging

NASA Astrophysics Data System (ADS)

Singh, Amit T.

2018-05-01

Upconversion quantum dots of tyrosine doped LaF3:Ce nanoparticles have been synthesized by wet chemical route. The thermal studies (TGA/DTA) confirm the crystallinity and stability of different phases of synthesized nanoparticles. The UV-Visible spectra show multiple absorption edges at 215.60 nm and 243.10 nm indicating quantum dot nature of the synthesized nanoparticles. The PL spectra showed upconversion with sharp emission peak at 615 nm (red colour). The FT-RAMAN spectra of the synthesized nanoparticles show the modification of the surface of the nanoparticles in the form of functional groups and skeletal groups. Upconversion nature of the synthesized nanoparticles indicates their potential application in bioimaging and biotagging.

Enhancing multiphoton upconversion through energy clustering at sublattice level

NASA Astrophysics Data System (ADS)

Wang, Juan; Deng, Renren; MacDonald, Mark A.; Chen, Bolei; Yuan, Jikang; Wang, Feng; Chi, Dongzhi; Andy Hor, Tzi Sum; Zhang, Peng; Liu, Guokui; Han, Yu; Liu, Xiaogang

2014-02-01

The applications of lanthanide-doped upconversionnanocrystals in biological imaging, photonics, photovoltaics and therapeutics have fuelled a growing demand for rational control over the emission profiles of the nanocrystals. A common strategy for tuning upconversion luminescence is to control the doping concentration of lanthanide ions. However, the phenomenon of concentration quenching of the excited state at high doping levels poses a significant constraint. Thus, the lanthanide ions have to be stringently kept at relatively low concentrations to minimize luminescence quenching. Here we describe a new class of upconversion nanocrystals adopting an orthorhombic crystallographic structure in which the lanthanide ions are distributed in arrays of tetrad clusters. Importantly, this unique arrangement enables the preservation of excitation energy within the sublattice domain and effectively minimizes the migration of excitation energy to defects, even in stoichiometric compounds with a high Yb3+ content (calculated as 98 mol%). This allows us to generate an unusual four-photon-promoted violet upconversion emission from Er3+ with an intensity that is more than eight times higher than previously reported. Our results highlight that the approach to enhancing upconversion through energy clustering at the sublattice level may provide new opportunities for light-triggered biological reactions and photodynamic therapy.

Photon up-conversion production in Tb{sup 3+}–Yb{sup 3+} co-doped CaF{sub 2} phosphors prepared by combustion synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rakov, Nikifor, E-mail: nikifor.gomez@univasf.edu.br; Guimarães, Renato B.; Maciel, Glauco S., E-mail: glauco@if.uff.br

2016-02-15

Graphical abstract: Up-conversion luminescence from Tb{sup 3+} obtained by energy transfer from Yb{sup 3+} pairs in CaF{sub 2} powder prepared by combustion synthesis. - Highlights: • Calcium fluoride (CaF{sub 2}) powders were prepared by combustion synthesis. • Rare-earth ions doped in this material were found in interstitial sites. • Cooperative up-conversion was observed in Tb{sup 3+}:Yb{sup 3+}:CaF{sub 2} powder. • Energy transfer between Tb{sup 3+} and pairs of Yb{sup 3+} was analyzed using rate equations. - Abstract: Calcium fluoride (CaF{sub 2}) crystalline powders were successfully prepared by the combustion synthesis method. The powder material containing luminescent rare-earth ions, more specificallymore » terbium (Tb{sup 3+}) and ytterbium (Yb{sup 3+}), was studied by X-ray diffraction, scanning electronic microscopy and optical spectroscopy. These ions are allocated in charge compensated interstitial positions of tetragonal (C{sub 4v}) and trigonal (C{sub 3v}) symmetry sites of the cubic (O{sub h}) CaF{sub 2} lattice. Up-conversion (UC) luminescence in Tb{sup 3+} was achieved using a low power diode laser operating at 975 nm. Tb{sup 3+} is insensitive to near-infrared radiation but UC can be achieved via energy transfer from pairs of Yb{sup 3+} ions to Tb{sup 3+} ions. The UC luminescence dynamics of Tb{sup 3+} was used to study the energy transfer mechanism.« less

The influence of Ag content and annealing time on structural and optical properties of SGS antimony-germanate glass doped with Er3+ ions

NASA Astrophysics Data System (ADS)

Zmojda, J.; Kochanowicz, M.; Miluski, P.; Baranowska, A.; Basa, A.; Jadach, R.; Sitarz, M.; Dorosz, D.

2018-05-01

A series of erbium doped SGS antimony-germanate glass embedding silver (Ag0) nanoparticles have been synthesized by a one-step melt-quench thermochemical reduction technique. The effect of NPs concentration and annealing time on the structural and photoluminescent (PL) properties were investigated. The Raman spectra as a function of temperature measured in-situ allow to determine the structural changes in vicinity of Ag+ ions and confirmed thermochemical reduction of Ag+ ions by Sb3+ ions. The surface plasmon resonance absorption band was evidenced near 450 nm. The impact of local field effect generated by Ag0 nanoparticles (NPs) and energy transfer from surface of silver NPs to trivalent erbium ions on near-infrared and up-conversion luminescence was described in terms of enhancement and quench phenomena.

Localized surface plasmons modulated nonlinear optical processes in metal film-coupled and upconversion nanocrystals-coated nanoparticles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lei, Dangyuan

2016-09-01

In the first part of this talk, I will show our experimental investigation on the linear and nonlinear optical properties of metal film-coupled nanosphere monomers and dimers both with nanometric gaps. We have developed a new methodology - polarization resolved spectral decomposition and color decoding to "visualizing" unambiguously the spectral and radiation properties of the complex plasmonic gap modes in these hybrid nanostructures. Single-particle spectroscopic measurements indicate that these hybrid nanostructures can simultaneously enhance several nonlinear optical processes, such as second harmonic generation, two-photon absorption induced luminescence, and hyper-Raman scattering. In the second part, I will show how the polarization state of the emissions from sub-10 nm upconversion nanocrystals (UCNCs) can be modulated when they form a hybrid complex with a gold nanorod (GNR). Our single-particle scattering experiments expose how an interplay between excitation polarization and GNR orientation gives rise to an extraordinary polarized nature of the upconversion emissions from an individual hybrid nanostructure. We support our results by numerical simulations and, using Förster resonance energy transfer theory, we uncover how an overlap between the UCNC emission and GNR extinction bands as well as the mutual orientation between emission and plasmonic dipoles jointly determine the polarization state of the UC emissions.

Water-stable NaLuF4-based upconversion nanophosphors with long-term validity for multimodal lymphatic imaging.

PubMed

Zhou, Jing; Zhu, Xingjun; Chen, Min; Sun, Yun; Li, Fuyou

2012-09-01

Multimodal imaging is rapidly becoming an important tool for biomedical applications because it can compensate for the deficiencies of individual imaging modalities. Herein, multifunctional NaLuF(4)-based upconversion nanoparticles (Lu-UCNPs) were synthesized though a facile one-step microemulsion method under ambient condition. The doping of lanthanide ions (Gd(3+), Yb(3+) and Er(3+)/Tm(3+)) endows the Lu-UCNPs with high T(1)-enhancement, bright upconversion luminescence (UCL) emissions, and excellent X-ray absorption coefficient. Moreover, the as-prepared Lu-UCNPs are stable in water for more than six months, due to the protection of sodium glutamate and diethylene triamine pentacetate acid (DTPA) coordinating ligands on the surface. Lu-UCNPs have been successfully applied to the trimodal CT/MR/UCL lymphatic imaging on the modal of small animals. It is worth noting that Lu-UCNPs could be used for imaging even after preserving for over six months. In vitro transmission electron microscope (TEM), methyl thiazolyl tetrazolium (MTT) assay and histological analysis demonstrated that Lu-UCNPs exhibited low toxicity on living systems. Therefore, Lu-UCNPs could be multimodal agents for CT/MR/UCL imaging, and the concept can be served as a platform technology for the next-generation of probes for multimodal imaging. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced performance of dye-sensitized solar cells based on TiO{sub 2} with NIR-absorption and visible upconversion luminescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Li; Yulin, Yang, E-mail: ylyang@hit.edu.cn; Mi, Zhou

2013-02-15

TiO{sub 2} with NIR-absorption and visible upconversion luminescence (UC-TiO{sub 2}) is prepared by a sol-gel method and calcined at 700 Degree-Sign C for 6 h. The material broadens the response region of dye sensitized solar cells (DSSCs) from an ultraviolet-visible region to the whole region of the solar spectrum. It shifts NIR sunlight to visible light which matches the strong absorbing region of the dye (N719). DSSCs based on UC-TiO{sub 2} achieved higher conversion efficiency than that on raw TiO{sub 2}. UC-TiO{sub 2} was mixed with commercial raw TiO{sub 2} as additive, and the short-circuit current density, open-circuit voltage andmore » conversion efficiency of the DSSC reached to the optimum values 13.38 mA/cm{sup 2}, 0.78 V and 6.63% (AM1.5 global), comparing with the blank values: 7.99 mA/cm{sup 2}, 0.75 V and 4.07%, respectively. Also the mechanisms of upconversion by multiphoton absorption and energy transfer processes are interpreted in this paper. - Graphical abstract: By introducing TiO{sub 2} with NIR-absorption and visible up-conversion luminescence into DSSC, a signal reflection was explored from ultra-violet region to visible region, and to near-IR region. Highlights: Black-Right-Pointing-Pointer TiO{sub 2} with NIR-absorption and visible up-conversion luminescence (UC-TiO{sub 2}) was prepared by a sol-gel method. Black-Right-Pointing-Pointer A systematic characterization and analysis was carried out to discuss the mechanism. Black-Right-Pointing-Pointer A significantly enhanced performance of DSSC was explored by using UC-TiO{sub 2} as an additive.« less

[A study on the concentration quenching of Tm3+ upconversion luminescence].

PubMed

Chen, B; Wang, H; Huang, S

2001-06-01

In this work, we have a designation and preparation of MFT glasses for upconversion, the glasses consisted of TeO2 and fluoride: PbF2, AlF3, BaF2, NaF and the impurity Tm2O3. In this glass system the oxide improve forming ability, the fluorides improve the microscopic environment around RE ions in glasses. In this glass host the content of Tm2O3 achieves to 4% mol and crystallization no occurred. A detail study on the concentration quenching of upconversion luminescence for 1G4-->3H6 and 1D2-->3H4 transitions was completed. The experimental results directed that the quenching concentration was 0.6 mol.% and higher 3 times than in other glasses materials. The cross relaxation and mechanism of concentration quenching were discussed.

Facile synthesis of hydrophilic multi-colour and upconversion photoluminescent mesoporous carbon nanoparticles for bioapplications.

PubMed

Kong, Qinglu; Zhang, Lingxia; Liu, Jianan; Wu, Meiying; Chen, Yu; Feng, Jingwei; Shi, Jianlin

2014-12-25

Hydrophilic mesoporous carbon nanoparticles (MCNs) have been synthesized via an extremely facile precursor carbonization-in-hot solvent route. The synthesized MCNs show well-defined particle and pore size distribution at around 100 nm and 2.7 nm, respectively, and multicolor and upconversion photoluminescence, which endow the MCNs with multicolor/upconversion bioimaging and drug delivery properties.

Highly Efficient LiYF4:Yb(3+), Er(3+) Upconversion Single Crystal under Solar Cell Spectrum Excitation and Photovoltaic Application.

PubMed

Chen, Xu; Xu, Wen; Song, Hongwei; Chen, Cong; Xia, Haiping; Zhu, Yongsheng; Zhou, Donglei; Cui, Shaobo; Dai, Qilin; Zhang, Jiazhong

2016-04-13

Luminescent upconversion is a promising way to harvest near-infrared (NIR) sunlight and transforms it into visible light that can be directly absorbed by active materials of solar cells and improve their power conversion efficiency (PCE). However, it is still a great challenge to effectively improve the PCE of solar cells with the assistance of upconversion. In this work, we demonstrate the application of the transparent LiYF4:Yb(3+), Er(3+) single crystal as an independent luminescent upconverter to improve the PCE of perovskite solar cells. The LiYF4:Yb(3+), Er(3+) single crystal is prepared by an improved Bridgman method, and its internal quantum efficiency approached to 5.72% under 6.2 W cm(-2) 980 nm excitation. The power-dependent upconversion luminescence indicated that under the excitation of simulated sunlight the (4)F(9/2)-(4)I(15/2) red emission originally results from the cooperation of a 1540 nm photon and a 980 nm photon. Furthermore, when the single crystal is placed in front of the perovskite solar cells, the PCE is enhanced by 7.9% under the irradiation of simulated sunlight by 7-8 solar constants. This work implies the upconverter not only can serve as proof of principle for improving PCE of solar cells but also is helpful to practical application.

Upconversion luminescence in BaMoO{sub 4}:Pr{sup 3+} phosphor for display devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soni, Abhishek Kumar; Rai, Vineet Kumar, E-mail: vineetkrrai@yahoo.co.in

2015-08-28

The frequency upconversion is an important nonlinear optical property by which near infrared light is converted into the visible light. The BaMoO{sub 4}:Pr{sup 3+} powder phosphor has been synthesized by solid state reaction method. The upconversion emission bands are recorded under the excitation of 808 nm diode laser. The phase formation of the prepared phosphor has been identified by powder X-ray diffraction (XRD) technique. The upconversion emission mechanism and colour coordinate have been explained by using energy level and CIE (International Commission on Illumination) chromaticity diagram study, respectively.

Cooperative upconversion luminescence in Tb{sup 3+}:Yb{sup 3+} co-doped Y{sub 2}SiO{sub 5} powders prepared by combustion synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rakov, Nikifor, E-mail: nikifor.gomez@univasf.edu.br; Vieira, Simone A.; Guimarães, Renato B.

2014-03-15

Frequency upconversion (UC) luminescence via cooperative energy transfer (CET) process between pairs of Yb{sup 3+} and Tb{sup 3+} ions was investigated in Tb{sup 3+}:Yb{sup 3+}:Y{sub 2}SiO{sub 5} crystalline ceramic powders prepared by combustion synthesis. Surface morphology and structure of the powders were investigated by scanning electronic microscopy and X-ray powder diffraction. Photoluminescence experiments were performed in Tb{sup 3+}-singly doped samples using ultraviolet light (λ=255 nm) and in Tb{sup 3+}:Yb{sup 3+} co-doped samples using a near-infrared (NIR) diode laser (λ=975 nm). Upon excitation with the NIR diode laser, UC luminescence with an intense emission band centered at ∼549 nm, corresponding tomore » the 4f intraband {sup 5}D{sub 4}→{sup 7}F{sub 5} transition of Tb{sup 3+}, along with less intense emission bands at ∼490, ∼590 and ∼620 nm, corresponding to other {sup 5}D{sub 4}→{sup 7}F{sub J} transitions, was detected. The CET rate was estimated by analyzing the dynamics of UC luminescence with rate equations model of the electronic populations. -- Graphical Abstract: Left: Cooperative upconversion luminescence spectra of three powder samples prepared by combustion synthesis. Right: The SEM image of the powder showing that it consists of agglomerated flake-like shaped particles of various sizes. Full scale bar is 20 μm. Highlights: • Yttrium orthosilicate (Y{sub 2}SiO{sub 5}) powders were prepared by combustion synthesis. • Cooperative upconversion is observed for the first time in Tb{sup 3+}–Yb{sup 3+} doped Y{sub 2}SiO{sub 5}. • Energy transfer and back-transfer rates between Tb{sup 3+} and Yb{sup 3+} pairs were estimated.« less

A novel upconversion@polydopamine core@shell nanoparticle based aptameric biosensor for biosensing and imaging of cytochrome c inside living cells.

PubMed

Ma, Lina; Liu, Fuyao; Lei, Zhen; Wang, Zhenxin

2017-01-15

Herein, a novel upconversion@polydopamine core@shell nanoparticle (termed as UCNP@PDA NP) -based aptameric biosensor has been fabricated for the quantitative analysis of cytochrome c (Cyt c) inside living cells, which comprises an UCNP@PDA NP, acting as an internal reference and fluorescence quenching agent, and Cy3 modified aptamer enabling ratiometric quantitative Cyt c measurement. After the hybridization of Cy3 labeled aptamer with amino-terminated single DNA on the UCNP@PDA NP surface (termed as UCNP@PDA@AP), the fluorescence of Cy3 can be efficiently quenched by the PDA shell. With the spontaneous cellular uptake of UCNP@PDA@AP, the Cyt c aptamer dissociates from UCNP@PDA NP surface through formation of aptamer-Cyt c complex, resulting in concomitant activation of the Cy3 fluorescence. High amount of Cyt c leads to high fluorescence emission, enabling direct visualization/measurement of the Cyt c by fluorescence microscopy/spectroscopy. The steady upconversion luminescent (UCL) signals can be employed not only for intracellular imaging, but also as an internal reference for evaluating intracellular Cyt c amount using the ratio of fluorescence intensity of Cy3 with the UCL intensity of UCNP. The UCNP@PDA@AP shows a reasonable detection limit (20nM) and large dynamic range (50nM to 10μM, which covers the literature reported values (1-10μM) for cytosolic Cyt c in apoptotic cells) for detecting Cyt c in buffer with excellent selectivity. In addition, the UCNP@PDA@AP has been successfully used to monitor etoposide induced intracellular releasing of Cyt c, providing the possibility for cell-based screening of apoptosis-inducing drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

A paper-based multiplexed resonance energy transfer nucleic acid hybridization assay using a single form of upconversion nanoparticle as donor and three quantum dots as acceptors.

PubMed

Doughan, Samer; Uddayasankar, Uvaraj; Peri, Aparna; Krull, Ulrich J

2017-04-15

Monodisperse aqueous upconverting nanoparticles (UCNPs) were covalently immobilized on aldehyde modified cellulose paper via reductive amination to evaluate the multiplexing capacity of luminescence resonance energy transfer (LRET) between UCNPs and quantum dots (QDs). This is the first account of a multiplexed bioassay strategy that demonstrates the principle of use of a single form of UCNP as donor and three different color emitting QDs as acceptors to concurrently determine three analytes. Broad absorbance profiles of green, orange and red QDs that spanned from the first exciton absorption peak to the UV region were in overlap with a blue emission band from UCNPs composed of NaYF 4 that was doped with 30% Yb 3+ , 0.5% Tm 3+ , allowing for LRET that was stimulated using 980 nm near-infrared radiation. The characteristic narrow and well-defined emission peaks of UCNPs and QDs allowed for the collection of luminescence from each nanoparticle using a band-pass optical filter and an epi-fluorescence microscope. The LRET system was used for the concurrent detection of uidA, Stx1A and tetA gene fragments with selectivity even in serum samples, and reached limits of detection of 26 fmol, 56 fmol and 76 fmol, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

NIR-to-visible upconversion nanoparticles for fluorescent labeling and targeted delivery of siRNA

NASA Astrophysics Data System (ADS)

Jiang, Shan; Zhang, Yong; Lim, Kian Meng; Sim, Eugene K. W.; Ye, Lei

2009-04-01

Near-infrared (NIR)-to-visible upconversion fluorescent nanoparticles were synthesized and used for imaging and targeted delivery of small interfering RNA (siRNA) to cancer cells. Silica-coated NaYF4 upconversion nanoparticles (UCNs) co-doped with lanthanide ions (Yb/Er) were synthesized. Folic acid and anti-Her2 antibody conjugated UCNs were used to fluorescently label the folate receptors of HT-29 cells and Her2 receptors of SK-BR-3 cells, respectively. The intracellular uptake of the folic acid and antibody conjugated UCNs was visualized using a confocal fluorescence microscope equipped with an NIR laser. siRNA was attached to anti-Her2 antibody conjugated UCNs and the delivery of these nanoparticles to SK-BR-3 cells was studied. Meanwhile, a luciferase assay was established to confirm the gene silencing effect of siRNA. Upconversion nanoparticles can serve as a fluorescent probe and delivery system for simultaneous imaging and delivery of biological molecules.

Investigating the evolution of local structure around Er and Yb in ZnO:Er and ZnO:Er, Yb on annealing using X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Anjana, R.; Jayaraj, M. K.; Yadav, A. K.; Jha, S. N.; Bhattacharyya, D.

2018-04-01

The local structure around Er and Yb centre in ZnO favouring upconversion luminescence was studied using EXAFS (Extended X-ray absorption fine structure spectroscopy). Due to the ionic radii difference between Zn and Er, Yb ions, the dopants cannot replace Zn in the ZnO lattice properly. Er2O3 and Yb2O3 impurity phases are formed at the grain boundaries of ZnO. It is found that the local structure around the Er centre in ZnO is modified on annealing in air. The symmetry around both erbium and ytterbium reduces with increase in annealing temperature. Symmetry reduction will favour the intra-4f transition and the energy transitions causing upconversion luminescence. By fitting the EXAFS data with theoretically simulated data, it is found that the Er centre forms a local structure similar to C4ν symmetry which is a distorted octahedron. On annealing the sample to 1200 °C, all the erbium centres are transformed to C4ν symmetry causing enhanced upconversion emission. Yb centre has also been modified on annealing. The decrease in co-ordination number with annealing temperature will decrease the symmetry and increase the near infrared absorption cross section. The decrease in symmetry around both the erbium and ytterbium centre and formation of C4ν symmetry around Er centre is the reason behind the activation of upconversion luminescence with high temperature annealing in both Er doped and Er, Yb co-doped ZnO samples. The study will be useful for the synthesis of high efficiency upconversion materials.

Light-Emitting Photon-Upconversion Nanoparticles in the Generation of Transdermal Reactive-Oxygen Species.

PubMed

Prieto, Martin; Rwei, Alina Y; Alejo, Teresa; Wei, Tuo; Lopez-Franco, Maria Teresa; Mendoza, Gracia; Sebastian, Victor; Kohane, Daniel S; Arruebo, Manuel

2017-12-06

Common photosensitizers used in photodynamic therapy do not penetrate the skin effectively. In addition, the visible blue and red lights used to excite such photosensitizers have shallow penetration depths through tissue. To overcome these limitations, we have synthesized ultraviolet- and visible-light-emitting, energy-transfer-based upconversion nanoparticles and coencapsulated them inside PLGA-PEG (methoxy poly(ethylene glycol)-b-poly(lactic-co-glycolic acid)) nanoparticles with the photosensitizer protoporphyrin IX. Nd 3+ has been introduced as a sensitizer in the upconversion nanostructure to allow its excitation at 808 nm. The subcytotoxic doses of the hybrid nanoparticles have been evaluated on different cell lines (i.e., fibroblasts, HaCaT, THP-1 monocytic cell line, U251MG (glioblastoma cell line), and mMSCs (murine mesenchymal stem cells). Upon NIR (near infrared)-light excitation, the upconversion nanoparticles emitted UV and VIS light, which consequently activated the generation of reactive-oxygen species (ROS). In addition, after irradiating at 808 nm, the resulting hybrid nanoparticles containing both upconversion nanoparticles and protoporphyrin IX generated 3.4 times more ROS than PLGA-PEG nanoparticles containing just the same dose of protoporphyrin IX. Their photodynamic effect was also assayed on different cell cultures, demonstrating their efficacy in selectively killing treated and irradiated cells. Compared to the topical application of the free photosensitizer, enhanced skin permeation and penetration were observed for the nanoparticulate formulation, using an ex vivo human-skin-permeation experiment. Whereas free protoporphyrin IX remained located at the outer layer of the skin, nanoparticle-encapsulated protoporphyrin IX was able to penetrate through the epidermal layer slightly into the dermis.

Upconversion induced enhancement of dye sensitized solar cells based on core-shell structured β-NaYF4:Er3+, Yb3+@SiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Zhou, Ziyao; Wang, Jiahong; Nan, Fan; Bu, Chenghao; Yu, Zhenhua; Liu, Wei; Guo, Shishang; Hu, Hao; Zhao, Xing-Zhong

2014-01-01

Upconversion materials have been employed as energy relay materials in dye sensitized solar cells (DSCs) to broaden the range of light absorption. However, the origin of the enhancements can be induced by both upconversion and size-dependent light scattering effects. To clarify the role of the upconversion material in the photoelectrode of DSCs, an upconversion induced device was realized here, which has the size-dependent light scattering effect eliminated via the application of NaYF4:Er3+, Yb3+@SiO2 upconversion nanoparticles (β-NYEY@SiO2 UCNPs). An enhancement of 6% in efficiency was observed for the device. This demonstration provided an insight into the possible further employment of upconversion in DSCs.Upconversion materials have been employed as energy relay materials in dye sensitized solar cells (DSCs) to broaden the range of light absorption. However, the origin of the enhancements can be induced by both upconversion and size-dependent light scattering effects. To clarify the role of the upconversion material in the photoelectrode of DSCs, an upconversion induced device was realized here, which has the size-dependent light scattering effect eliminated via the application of NaYF4:Er3+, Yb3+@SiO2 upconversion nanoparticles (β-NYEY@SiO2 UCNPs). An enhancement of 6% in efficiency was observed for the device. This demonstration provided an insight into the possible further employment of upconversion in DSCs. Electronic supplementary information (ESI) available: Details of preparations and characterizations; the TEM images, EDX measurements, XRD measurements and upconversion emission spectrum of bared β-NYEY nanocrystals; SEM and AFM images of the photoelectrode with different concentrations of β-NYEY nanocrystals; J-V characteristics, EIS measurements and fitted EIS parameters of the DSCs based on five different photoelectrodes. See DOI: 10.1039/c3nr04315k

The laser-diode-excited 5 d-4 f luminescence of Ce3+ and Pr3+ ions embedded into a BaR2F8 matrix

NASA Astrophysics Data System (ADS)

Pushkar', A. A.; Uvarova, T. V.; Kozlova, N. S.; Kuznetsov, S. Yu.; Uvarova, A. G.

2013-06-01

We show the possibility of obtaining UV luminescence from 5 d-4 f transitions of rare-earth ions in the BaY2F8: (Yb3+, Pr3+, Ce3+) crystal under upconversion excitation by standard laser diodes with lasing wavelengths of 960, 808, and 840 nm. Various upconversion mechanisms of pumping for populating the higher-lying energy levels of the active ions, as well as methods of adaptation of the active medium BaY2F8: (Yb3+, Pr3+, Ce3+) to these mechanisms, are considered.

Enantiopure distorted ribbon-shaped nanographene combining two-photon absorption-based upconversion and circularly polarized luminescence.

PubMed

Cruz, Carlos M; Márquez, Irene R; Mariz, Inês F A; Blanco, Victor; Sánchez-Sánchez, Carlos; Sobrado, Jesús M; Martín-Gago, José A; Cuerva, Juan M; Maçôas, Ermelinda; Campaña, Araceli G

2018-04-28

Herein we describe a distorted ribbon-shaped nanographene exhibiting unprecedented combination of optical properties in graphene-related materials, namely upconversion based on two-photon absorption (TPA-UC) together with circularly polarized luminescence (CPL). The compound is a graphene molecule of ca. 2 nm length and 1 nm width with edge defects that promote the distortion of the otherwise planar lattice. The edge defects are an aromatic saddle-shaped ketone unit and a [5]carbohelicene moiety. This system is shown to combine two-photon absorption and circularly polarized luminescence and a remarkably long emission lifetime of 21.5 ns. The [5]helicene is responsible for the chiroptical activity while the push-pull geometry and the extended network of sp 2 carbons are factors favoring the nonlinear absorption. Electronic structure theoretical calculations support the interpretation of the results.

Near-infrared-to-near-infrared down-shifting and upconversion luminescence of KY{sub 3}F{sub 10} with single dopant of Nd{sup 3+} ion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Huihong; State Key Laboratory of Luminescence Materials and Devices and Institute of Optical Communication Materials, South China University of Technology, Guangzhou 510641; Yu, Ting

2016-01-25

We have studied the structural and near-infrared (NIR) luminescent properties of KY{sub 3}F{sub 10} phosphors, singly doped with Nd{sup 3+} serving as both sensitizer and activator. With a single laser diode at the wavelength of 808 nm as a pump source, simultaneous NIR-to-NIR upconversion (UC) and down-shifting (DS) emissions are effectively achieved, due to the specific energy levels of Nd{sup 3+} dopant and the low phonon energy of the host. The luminescence mechanism related to energy transfer is discussed. The luminescence can be modulated through controlling the population of Nd{sup 3+}:{sup 4}F{sub 3/2} state in our experiment. Interestingly, both UC andmore » DS emissions of the material fall within the dual biological window, suggesting that the prepared phosphors have potential applications in the bioimaging field.« less

Gold decorated NaYF4:Yb,Er/NaYF4/silica (core/shell/shell) upconversion nanoparticles for photothermal destruction of BE(2)-C neuroblastoma cells

NASA Astrophysics Data System (ADS)

Qian, Li Peng; Zhou, Li Han; Too, Heng-Phon; Chow, Gan-Moog

2011-02-01

Gold decorated NaYF4:Yb,Er/NaYF4/silica (core/shell/shell) upconversion (UC) nanoparticles ( 70-80 nm) were synthesized using tetraethyl orthosilicate and chloroauric acid in a one-step reverse microemulsion method. Gold nanoparticles ( 6 nm) were deposited on the surface of silica shell of these core/shell/shell nanoparticles. The total upconversion emission intensity (green, red, and blue) of the core/shell/shell nanoparticles decreased by 31% after Au was deposited on the surface of silica shell. The upconverted green light was coupled with the surface plasmon of Au leading to rapid heat conversion. These UC/silica/Au nanoparticles were very efficient to destroy BE(2)-C cancer cells and showed strong potential in photothermal therapy.

A multifunctional probe for ICP-MS determination and multimodal imaging of cancer cells.

PubMed

Yang, Bin; Zhang, Yuan; Chen, Beibei; He, Man; Yin, Xiao; Wang, Han; Li, Xiaoting; Hu, Bin

2017-10-15

Inductively coupled plasma-mass spectrometry (ICP-MS) based bioassay and multimodal imaging have attracted increasing attention in the current development of cancer research and theranostics. Herein, a sensitive, simple, timesaving, and reliable immunoassay for cancer cells counting and dual-modal imaging was proposed by using ICP-MS detection and down-conversion fluorescence (FL)/upconversion luminescence (UCL) with the aid of a multifunctional probe for the first time. The probe consisted of a recognition unit of goat anti-mouse IgG to label the anti-EpCAM antibody attached cells, a fluorescent dye (Cy3) moiety for FL imaging as well as upconversion nanoparticles (UCNPs) tag for both ICP-MS quantification and UCL imaging of cancer cells. Under the optimized conditions, an excellent linearity and sensitivity were achieved owing to the signal amplification effect of nanoparticles and low spectral interference. Accordingly, a limit of detection (3σ) of 1×10 2 HepG2 cells and a relative standard deviation of 7.1% for seven replicate determinations of 1×10 3 HepG2 cells were obtained. This work proposed a method to employ UCNPs with highly integrated functionalities enabling us not only to count but also to see the cancer cells, opening a promising avenue for biological research and clinical theranostics. Copyright © 2017 Elsevier B.V. All rights reserved.

Detection of early primary colorectal cancer with upconversion luminescent NP-based molecular probes

NASA Astrophysics Data System (ADS)

Liu, Chunyan; Qi, Yifei; Qiao, Ruirui; Hou, Yi; Chan, Kaying; Li, Ziqian; Huang, Jiayi; Jing, Lihong; Du, Jun; Gao, Mingyuan

2016-06-01

Early detection and diagnosis of cancers is extremely beneficial for improving the survival rate of cancer patients and molecular imaging techniques are believed to be relevant for offering clinical solutions. Towards early cancer detection, we developed a primary animal colorectal cancer model and constructed a tumor-specific imaging probe by using biocompatible NaGdF4:Yb,Er@NaGdF4 upconversion luminescent NPs for establishing a sensitive early tumor imaging method. The primary animal tumor model, which can better mimic the human colorectal cancer, was built upon continual administration of 1,2-dimethylhydrazine in Kunming mice and the tumor development was carefully monitored through histopathological and immunohistochemical analyses to reveal the pathophysiological processes and molecular features of the cancer microenvironment. The upconversion imaging probe was constructed through covalent coupling of PEGylated core-shell NPs with folic acid whose receptor is highly expressed in the primary tumors. Upon 980 nm laser excitation, the primary colorectal tumors in the complex abdominal environment were sensitively imaged owing to the ultralow background of the upconversion luminescence and the high tumor-targeting specificity of the nanoprobe. We believe that the current studies provide a highly effective and potential approach for early colorectal cancer diagnosis and tumor surgical navigation.Early detection and diagnosis of cancers is extremely beneficial for improving the survival rate of cancer patients and molecular imaging techniques are believed to be relevant for offering clinical solutions. Towards early cancer detection, we developed a primary animal colorectal cancer model and constructed a tumor-specific imaging probe by using biocompatible NaGdF4:Yb,Er@NaGdF4 upconversion luminescent NPs for establishing a sensitive early tumor imaging method. The primary animal tumor model, which can better mimic the human colorectal cancer, was built upon continual administration of 1,2-dimethylhydrazine in Kunming mice and the tumor development was carefully monitored through histopathological and immunohistochemical analyses to reveal the pathophysiological processes and molecular features of the cancer microenvironment. The upconversion imaging probe was constructed through covalent coupling of PEGylated core-shell NPs with folic acid whose receptor is highly expressed in the primary tumors. Upon 980 nm laser excitation, the primary colorectal tumors in the complex abdominal environment were sensitively imaged owing to the ultralow background of the upconversion luminescence and the high tumor-targeting specificity of the nanoprobe. We believe that the current studies provide a highly effective and potential approach for early colorectal cancer diagnosis and tumor surgical navigation. Electronic supplementary information (ESI) available: (1) Molecular structure of Jeffamine-modified FA; (2) immunohistochemical analysis of FR expression in the colorectal tissue derived from mice treated with NaCl at different weeks; (3) biodistributions of probes of NP-FA and NP-IgG in the main organs of mice. See DOI: 10.1039/c5nr07858j

Near-infrared photocatalysts of BiVO4/CaF2:Er3+, Tm3+, Yb3+ with enhanced upconversion properties

NASA Astrophysics Data System (ADS)

Huang, Shouqiang; Zhu, Nanwen; Lou, Ziyang; Gu, Lin; Miao, Chen; Yuan, Haiping; Shan, Aidang

2014-01-01

Upconversion photocatalysts have the potential to absorb the near-infrared (NIR) light in solar energy and improve the photocatalytic performance. A hierarchical upconversion photocatalyst of BiVO4 (BVO)/CaF2:Er3+, Tm3+, Yb3+ (CF) combined with the narrow-band semiconductor of BVO and the luminescence agent of CF to enhance upconversion properties was synthesized via the hydrothermal method. The CF particles were deposited homogeneously on the surface of the BVO/CF composite with regular dendritic structure, which led to efficient upconversion emissions. The upconversion emission intensity of the BVO/CF composite was 8 times higher than that of pure CF, through tailoring the crystal symmetry of lanthanide ions by Bi3+ ions. The upconverted ultraviolet (361 and 379 nm), violet (408 nm), and blue (485 nm) light was able to excite BVO for photocatalysis in BVO/CF under NIR irradiation, which improved the degradation rate of methyl orange (MO).Upconversion photocatalysts have the potential to absorb the near-infrared (NIR) light in solar energy and improve the photocatalytic performance. A hierarchical upconversion photocatalyst of BiVO4 (BVO)/CaF2:Er3+, Tm3+, Yb3+ (CF) combined with the narrow-band semiconductor of BVO and the luminescence agent of CF to enhance upconversion properties was synthesized via the hydrothermal method. The CF particles were deposited homogeneously on the surface of the BVO/CF composite with regular dendritic structure, which led to efficient upconversion emissions. The upconversion emission intensity of the BVO/CF composite was 8 times higher than that of pure CF, through tailoring the crystal symmetry of lanthanide ions by Bi3+ ions. The upconverted ultraviolet (361 and 379 nm), violet (408 nm), and blue (485 nm) light was able to excite BVO for photocatalysis in BVO/CF under NIR irradiation, which improved the degradation rate of methyl orange (MO). Electronic supplementary information (ESI) available: Additional tables and figures. See DOI: 10.1039/c3nr05266d

Taking the temperature of the interiors of magnetically heated nanoparticles.

PubMed

Dong, Juyao; Zink, Jeffrey I

2014-05-27

The temperature increase inside mesoporous silica nanoparticles induced by encapsulated smaller superparamagnetic nanocrystals in an oscillating magnetic field is measured using a crystalline optical nanothermometer. The detection mechanism is based on the temperature-dependent intensity ratio of two luminescence bands in the upconversion emission spectrum of NaYF4:Yb(3+), Er(3+). A facile stepwise phase transfer method is developed to construct a dual-core mesoporous silica nanoparticle that contains both a nanoheater and a nanothermometer in its interior. The magnetically induced heating inside the nanoparticles varies with different experimental conditions, including the magnetic field induction power, the exposure time to the magnetic field, and the magnetic nanocrystal size. The temperature increase of the immediate nanoenvironment around the magnetic nanocrystals is monitored continuously during the magnetic oscillating field exposure. The interior of the nanoparticles becomes much hotter than the macroscopic solution and cools to the temperature of the ambient fluid on a time scale of seconds after the magnetic field is turned off. This continuous absolute temperature detection method offers quantitative insight into the nanoenvironment around magnetic materials and opens a path for optimizing local temperature controls for physical and biomedical applications.

Simultaneous isolation and detection of circulating tumor cells with a microfluidic silicon-nanowire-array integrated with magnetic upconversion nanoprobes.

PubMed

Wang, Chao; Ye, Min; Cheng, Liang; Li, Rui; Zhu, Wenwen; Shi, Zhen; Fan, Chunhai; He, Jinkang; Liu, Jian; Liu, Zhuang

2015-06-01

The development of sensitive and convenient methods for detection, enrichment, and analysis of circulating tumor cells (CTCs), which serve as an importance diagnostic indicator for metastatic progression of cancer, has received tremendous attention in recent years. In this work, a new approach characteristic of simultaneous CTC capture and detection is developed by integrating a microfluidic silicon nanowire (SiNW) array with multifunctional magnetic upconversion nanoparticles (MUNPs). The MUNPs were conjugated with anti-EpCAM antibody, thus capable to specifically recognize tumor cells in the blood samples and pull them down under an external magnetic field. The capture efficiency of CTCs was further improved by the integration with a microfluidic SiNW array. Due to the autofluorescence free nature in upconversion luminescence (UCL) imaging, our approach allows for highly sensitive detection of small numbers of tumor cells, which afterward could be collected for further analysis and re-culturing. We have further demonstrated that this approach can be applied to detect CTCs in clinical blood samples from lung cancer patients, and obtained consistent results by analyzing the UCL signals and the clinical outcomes of lung cancer metastasis. Therefore our approach represents a promising platform in CTC capture and detection with potential clinical utilization in cancer diagnosis and prognosis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Upconversion excitations in Pr3+-doped BaY2F8 crystal

NASA Astrophysics Data System (ADS)

Piramidowicz, R.; Mahiou, R.; Boutinaud, P.; Malinowski, M.

2011-09-01

We report the orange-to-blue and infrared-(IR)-to-blue wavelengths upconversion luminescence in Pr3+:BaY2F8 crystals. Mechanism of the orange light upconversion into blue 3P0 state emission was confirmed to be energy transfer between two Pr3+ ions in the 1D2 state. IR-to-blue upconversion has only been observed under two different color IR pumping. The first resonant step was the 3H4→1G4 ground state absorption transition, and the second resonant transition was the excited state absorption from the 1G4 to 1I6 and 3PJ levels. A comparison of the efficiency of the IR-to-blue upconversion in several praseodymium activated host is presented and discussed. A model of the IR pumped upconversion praseodymium blue laser is presented and the population inversion conditions are calculated.

Yb3+-Er3+-Tm3+ co-doped nano-glass-ceramics tuneable up-conversion phosphor

NASA Astrophysics Data System (ADS)

Méndez-Ramos, J.; Rodriguez, V. D.; Tikhomirov, V. K.; Del-Castillo, J.; Yanes, A. C.

2008-08-01

Transparent Yb3+-Er3+-Tm3+ co-doped nano-glass-ceramics have been prepared, 32(SiO{2}) 9(AlO{1.5}) 31.5(CdF{2}) 18.5(PbF{2}) 5.5(ZnF{2}): 3.5(Yb-Er-TmF{3}) mol%, where the co-dopants partition mostly to the fluoride PbF{2}-based nano-crystals. A comparative study of the up-conversion luminescence in nano-glass-ceramics and its precursor glass indicates that these materials can be used as blue/green/red tuneable up-conversion phosphor, in particular for white light generation. A ratio between blue, green and red emission bands of the Tm3+ and Er3+ can be widely varied with nano-ceramming of the precursor glass and with changing a pump power of luminescence. The change in the ratio between the blue, green and red emission bands is explained to be due to substantial lowering phonon energy and shortening of inter-dopant distances with nano-ceramming of the precursor glass and due to change in the ratio of 2- and 3-photon up-conversion processes with pump power.

Structural morphology, upconversion luminescence and optical thermometric sensing behavior of Y2O3:Er(3+)/Yb(3+) nano-crystalline phosphor.

PubMed

Joshi, C; Dwivedi, A; Rai, S B

2014-08-14

Infrared-to-visible upconverting rare earths Er(3+)/Yb(3+) co-doped Y2O3 nano-crystalline phosphor samples have been prepared by solution combustion method followed by post-heat treatment at higher temperatures. A slight increase in average crystallite size has been found on calcinations verified by X-ray analysis. Transmission electron microscopy (TEM) confirms the nano-crystalline nature of the as-prepared and calcinated samples. Fourier transform infrared (FTIR) analysis shows the structural changes in as-prepared and calcinated samples. Upconversion and downconversion emission recorded using 976 and 532 nm laser sources clearly demonstrates a better luminescence properties in the calcinated samples as compared to as-prepared sample. Upconversion emission has been quantified in terms of standard chromaticity diagram (CIE) showing a shift in overall upconversion emission of as-prepared and calcinated samples. Temperature sensing behaviour of this material has also been investigated by measurement of fluorescence intensity ratio (FIR) of various signals in green emission in the temperature range of 315 to 555 K under 976 nm laser excitation. Copyright © 2014 Elsevier B.V. All rights reserved.

Excitonic luminescence upconversion in a two-dimensional semiconductor

DOE PAGES

Jones, Aaron M.; Yu, Hongyi; Schaibley, John R.; ...

2015-12-21

Photon upconversion is an elementary light-matter interaction process in which an absorbed photon is re-emitted at higher frequency after extracting energy from the medium. Furthermore, this phenomenon lies at the heart of optical refrigeration in solids(1), where upconversion relies on anti-Stokes processes enabled either by rare-earth impurities(2) or exciton-phonon coupling(3). We demonstrate a luminescence upconversion process from a negatively charged exciton to a neutral exciton resonance in monolayer WSe2, producing spontaneous anti-Stokes emission with an energy gain of 30 meV. Polarization-resolved measurements find this process to be valley selective, unique to monolayer semiconductors(4). Since the charged exciton binding energy(5) closelymore » matches the 31 meV A(1)' optical phonon(6-9), we ascribe the spontaneous excitonic anti-Stokes to doubly resonant Raman scattering, where the incident and outgoing photons are in resonance with the charged and neutral excitons, respectively. Additionally, we resolve a charged exciton doublet with a 7 meV splitting, probably induced by exchange interactions, and show that anti-Stokes scattering is efficient only when exciting the doublet peak resonant with the phonon, further confirming the excitonic doubly resonant picture.« less

High sensitivity of gold nanoparticles co-doped with Gd2O3 mesoporous silica nanocomposite to nasopharyngeal carcinoma cells

NASA Astrophysics Data System (ADS)

Wang, Hui; Zhang, Songjin; Tian, Xiumei; Liu, Chufeng; Zhang, Lei; Hu, Wenyong; Shao, Yuanzhi; Li, Li

2016-10-01

Nanoprobes for combined optical and magnetic resonance imaging have tremendous potential in early cancer diagnosis. Gold nanoparticles (AuNPs) co-doped with Gd2O3 mesoporous silica nanocomposite (Au/Gd@MCM-41) can produce pronounced contrast enhancement for T1 weighted image in magnetic resonance imaging (MRI). Here, we show the remarkably high sensitivity of Au/Gd@MCM-41 to the human poorly differentiated nasopharyngeal carcinoma (NPC) cell line (CNE-2) using fluorescence lifetime imaging (FLIM). The upconversion luminescences from CNE-2 and the normal nasopharyngeal (NP) cells (NP69) after uptake of Au/Gd@MCM-41 show the characteristic of two-photon-induced-radiative recombination of the AuNPs. The presence of the Gd3+ ion induces a much shorter luminescence lifetime in CNE-2 cells. The interaction between AuNPs and Gd3+ ion clearly enhances the optical sensitivity of Au/Gd@MCM-41 to CNE-2. Furthermore, the difference in the autofluorescence between CNE-2 and NP69 cells can be efficiently demonstrated by the emission lifetimes of Au/Gd@MCM-41 through the Forster energy transfers from the endogenous fluorophores to AuNPs. The results suggest that Au/Gd@MCM-41 may impart high optical resolution for the FLIM imaging that differentiates normal and high-grade precancers.

Upconversion in solar cells

PubMed Central

2013-01-01

The possibility to tune chemical and physical properties in nanosized materials has a strong impact on a variety of technologies, including photovoltaics. One of the prominent research areas of nanomaterials for photovoltaics involves spectral conversion. Modification of the spectrum requires down- and/or upconversion or downshifting of the spectrum, meaning that the energy of photons is modified to either lower (down) or higher (up) energy. Nanostructures such as quantum dots, luminescent dye molecules, and lanthanide-doped glasses are capable of absorbing photons at a certain wavelength and emitting photons at a different (shorter or longer) wavelength. We will discuss upconversion by lanthanide compounds in various host materials and will further demonstrate upconversion to work for thin-film silicon solar cells. PMID:23413889

Photoluminescence upconversion at GaAs /InGa P2 interfaces driven by a sequential two-photon absorption mechanism

NASA Astrophysics Data System (ADS)

Hylton, N. P.; Hinrichsen, T. F.; Vaquero-Stainer, A. R.; Yoshida, M.; Pusch, A.; Hopkinson, M.; Hess, O.; Phillips, C. C.; Ekins-Daukes, N. J.

2016-06-01

This paper reports on the results of an investigation into the nature of photoluminescence upconversion at GaAs /InGa P2 interfaces. Using a dual-beam excitation experiment, we demonstrate that the upconversion in our sample proceeds via a sequential two-photon optical absorption mechanism. Measurements of photoluminescence and upconversion photoluminescence revealed evidence of the spatial localization of carriers in the InGa P2 material, arising from partial ordering of the InGa P2 . We also observed the excitation of a two-dimensional electron gas at the GaAs /InGa P2 heterojunction that manifests as a high-energy shoulder in the GaAs photoluminescence spectrum. Furthermore, the results of upconversion photoluminescence excitation spectroscopy demonstrate that the photon energy onset of upconversion luminescence coincides with the energy of the two-dimensional electron gas at the GaAs /InGa P2 interface, suggesting that charge accumulation at the interface can play a crucial role in the upconversion process.

Lanthanide-doped NaScF4 nanoprobes: crystal structure, optical spectroscopy and biodetection

NASA Astrophysics Data System (ADS)

Ai, Yu; Tu, Datao; Zheng, Wei; Liu, Yongsheng; Kong, Jintao; Hu, Ping; Chen, Zhuo; Huang, Mingdong; Chen, Xueyuan

2013-06-01

Trivalent lanthanide ions (Ln3+)-doped inorganic nanoparticles (NPs) as potential luminescent bioprobes have been attracting tremendous interest because of their unique upconversion (UC) and downconversion (DC) luminescence properties. NaScF4, as an important host material, has been rarely reported and its crystal structure remains unclear. Herein, based on the single crystal X-ray diffraction, the space group of NaScF4 crystals was determined to be P31 containing multiple sites of Sc3+ with crystallographic site symmetry of C1, which was verified by high-resolution photoluminescence spectroscopy of Eu3+ at low temperature (10 K). Furthermore, monodisperse and size-controllable NaScF4:Ln3+ NPs were synthesized via a facile thermal decomposition method. The biotinylated NaScF4:Er3+/Yb3+ NPs were demonstrated for their applications as a heterogeneous UC luminescence bioprobe to detect avidin with a detection limit of 180 pM. After bioconjugation with amino-terminal fragment (ATF) of urokinase plasminogen activator (uPA), NaScF4:Ln3+ NPs also exhibited specific recognition of cancer cells overexpressed with uPA receptor (uPAR, an important marker of tumor biology and metastasis), showing great potentials in tumor-targeted bioimaging.Trivalent lanthanide ions (Ln3+)-doped inorganic nanoparticles (NPs) as potential luminescent bioprobes have been attracting tremendous interest because of their unique upconversion (UC) and downconversion (DC) luminescence properties. NaScF4, as an important host material, has been rarely reported and its crystal structure remains unclear. Herein, based on the single crystal X-ray diffraction, the space group of NaScF4 crystals was determined to be P31 containing multiple sites of Sc3+ with crystallographic site symmetry of C1, which was verified by high-resolution photoluminescence spectroscopy of Eu3+ at low temperature (10 K). Furthermore, monodisperse and size-controllable NaScF4:Ln3+ NPs were synthesized via a facile thermal decomposition method. The biotinylated NaScF4:Er3+/Yb3+ NPs were demonstrated for their applications as a heterogeneous UC luminescence bioprobe to detect avidin with a detection limit of 180 pM. After bioconjugation with amino-terminal fragment (ATF) of urokinase plasminogen activator (uPA), NaScF4:Ln3+ NPs also exhibited specific recognition of cancer cells overexpressed with uPA receptor (uPAR, an important marker of tumor biology and metastasis), showing great potentials in tumor-targeted bioimaging. Electronic supplementary information (ESI) available: Crystallographic data (CCDC 931481) in CIF format. EDX analysis of NaScF4:Er3+/Yb3+ NPs. 10 K PL excitation spectra of NaScF4:Eu3+ microcrystals. Selected bond lengths and angles for NaScF4 crystals. Atomic coordinates and equivalent isotropic displacement parameters for NaScF4 crystals. UC quantum yield data of NaScF4:Er3+/Yb3+ NPs. See DOI: 10.1039/c3nr01529g

Er-doped lead borate glasses and transparent glass ceramics for near-infrared luminescence and up-conversion applications.

PubMed

Pisarski, Wojciech A; Goryczka, Tomasz; Pisarska, Joanna; Ryba-Romanowski, Witold

2007-03-15

Lead borate based glasses have been analyzed using Raman and infrared spectroscopy. The formation of different borate groups and the direction of BO3 <--> BO4 conversion strongly depends on the PbO- and/or PbF2-to-B2O3 ratio in chemical composition. PbF2-PbO-B2O3 based glasses containing Er3+ ions have been studied after annealing. The orthorhombic PbF2 crystallites are formed during thermal treatment, which was evidenced by X-ray diffraction analysis. Near-infrared luminescence at 1530 nm and green up-conversion at 545 nm have been registered for samples before and after annealing. The luminescence bands correspond to 4I13/2-4I15/2 and 4S3/2-4I15/2 transitions of Er3+ ions, respectively. In comparison to the precursor glasses, the luminescence intensities are higher in the studied transparent oxyfluoride glass ceramics. Simultaneously, the half-width of the luminescence lines slightly decreases. It can be the evidence that a small amount of the Er3+ ions is incorporated into the orthorhombic PbF2 phase.

Rare-earth doped transparent nano-glass-ceramics: a new generation of photonic integrated devices

NASA Astrophysics Data System (ADS)

Rodríguez-Armas, Vicente Daniel; Tikhomirov, Victor K.; Méndez-Ramos, Jorge; Yanes, Angel C.; Del-Castillo, Javier; Furniss, David; Seddon, Angela B.

2007-05-01

We report on optical properties and prospect applications on rare-earth doped oxyfluoride precursor glass and ensuing nano-glass-ceramics. We find out the spectral optical gain of the nano-glass-ceramics and show that its flatness and breadth are advantageous as compared to contemporary used erbium doped optical amplifiers. We present the possibility of flat gain cross-section erbium doped waveguide amplifiers as short 'chip', all-optical, devices capable of dense wavelength division multiplexing, including the potential for direct writing of these devices inside bulk glasses for three-dimensional photonic integration. We carried out a comparative study of the up-conversion luminescence in Er 3+-doped and Yb 3+-Er 3+-Tm 3+ co-doped samples, which indicates that these materials can be used as green/red tuneable up-conversion phosphors and white light simulation respectively. Observed changes in the spectra of the up-conversion luminescence provide a tool for tuning the colour opening the way for producing 3-dimensional optical recording.

High Resolution Fluorescence Imaging of Cancers Using Lanthanide Ion-Doped Upconverting Nanocrystals

PubMed Central

Naccache, Rafik; Rodríguez, Emma Martín; Bogdan, Nicoleta; Sanz-Rodríguez, Francisco; de la Cruz, Maria del Carmen Iglesias; de la Fuente, Ángeles Juarranz; Vetrone, Fiorenzo; Jaque, Daniel; Solé, José García; Capobianco, John A.

2012-01-01

During the last decade inorganic luminescent nanoparticles that emit visible light under near infrared (NIR) excitation (in the biological window) have played a relevant role for high resolution imaging of cancer. Indeed, semiconductor quantum dots (QDs) and metal nanoparticles, mostly gold nanorods (GNRs), are already commercially available for this purpose. In this work we review the role which is being played by a relatively new class of nanoparticles, based on lanthanide ion doped nanocrystals, to target and image cancer cells using upconversion fluorescence microscopy. These nanoparticles are insulating nanocrystals that are usually doped with small percentages of two different rare earth (lanthanide) ions: The excited donor ions (usually Yb3+ ion) that absorb the NIR excitation and the acceptor ions (usually Er3+, Ho3+ or Tm3+), that are responsible for the emitted visible (or also near infrared) radiation. The higher conversion efficiency of these nanoparticles in respect to those based on QDs and GNRs, as well as the almost independent excitation/emission properties from the particle size, make them particularly promising for fluorescence imaging. The different approaches of these novel nanoparticles devoted to “in vitro” and “in vivo” cancer imaging, selective targeting and treatment are examined in this review. PMID:24213500

Two-photon absorption and upconversion luminescence of colloidal CsPbX3 quantum dots

NASA Astrophysics Data System (ADS)

Han, Qiuju; Wu, Wenzhi; Liu, Weilong; Yang, Qingxin; Yang, Yanqiang

2018-01-01

The nonlinear optical and the upconversion luminescence (UCL) properties of CsPbX3 (X = Br or its binary mixtures with Cl, I) quantum dots (QDs) are investigated by femtosecond open-aperture (OA) Z-scan and time-resolved luminescence techniques in nonresonant spectral region. The OA Z-scan results show that CsPbX3 QDs have strong reverse saturable absorption (RSA), which is ascribed to two-photon absorption. Partially changing halide composition from Cl to Br, to I, two-photon absorption cross sections become larger at the same laser excitation intensity. The composition-tunable nonlinear absorption should be attributed to the gradual decrease of the lowest direct band gaps with the halide substitute. Moreover, the strong UCL can be observed under near infrared femtosecond laser excitation. Halide composition-tunable UCL dynamics of CsPbX3 QDs is analyzed by use of two-exponential fitting with deconvolution. When CsPbX3 QDs have similar sizes (10-13 nm), with partially changing halide composition from Cl to Br, to I, the average UCL lifetime becomes longer due to the variation of Kane energy. Our findings suggest all-inorganic perovskite QDs can be used as excellent gain medium for high-performance frequency-upconversion lasers and provide reference to engineer such QDs toward practical optoelectronic applications.

PEGylated NaLuF4: Yb/Er upconversion nanophosphors for in vivo synergistic fluorescence/X-ray bioimaging and long-lasting, real-time tracking.

PubMed

Yi, Zhigao; Lu, Wei; Xu, Yaru; Yang, Jing; Deng, Li; Qian, Chao; Zeng, Tianmei; Wang, Haibo; Rao, Ling; Liu, Hongrong; Zeng, Songjun

2014-12-01

Simultaneous in vivo luminescence and X-ray bioimaging in a tissue or animal integrates the advantages of each single-modal imaging technology, and will find widespread application in biological and clinical fields. However, synergistic dual-modal bioimaging that utilizes a new generation of upconversion nanoprobes is still limited. In addition, investigations concentrated on in vivo biodistribution of these nanoprobes may contribute to diagnosis and treatment, but long-term in vivo tracking based on these nanoprobes is rarely reported. In this work, water-soluble NaLuF4: Yb/Er nanophosphors were prepared through modified one-pot simultaneous synthesis and surface modification method. Owing to the outstanding upconverting emissions and large X-ray absorption coefficient/K-edge value of Lu and doped Yb ions, the obtained nanoprobes were successfully used as luminescent nanoprobes and X-ray contrast agents for in vivo synergistic upconversion luminescence and X-ray bioimaging. The in vivo biodistribution of these nanoprobes were observed, and the results based on long-term tracking reveal that the as-prepared nanoprobes first aggregated in the lung of the mouse, transferred to the liver, and finally moved to the spleen. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microwave hydrothermal synthesis and upconversion properties of Yb3+/Er3+ doped YVO4 nanoparticles

NASA Astrophysics Data System (ADS)

Kshetri, Yuwaraj K.; Regmi, Chhabilal; Kim, Hak-Soo; Wohn Lee, Soo; Kim, Tae-Ho

2018-05-01

Yb3+ and Er3+ doped YVO4 (Yb3+/Er3+:YVO4) nanoparticles with highly efficient near-infrared to visible upconversion properties have been synthesized by microwave hydrothermal process. Uniform-sized Yb3+/Er3+:YVO4 nanoparticles were synthesized within 1 h at 140 °C which is relatively faster than the conventional hydrothermal process. Under 980 nm laser excitation, strong green and less strong red emissions are observed which are attributed to 2H11/2, 4S3/2 to 4I15/2 and 4F9/2 to 4I15/2 transitions of Er3+ respectively. The emission intensity is found to depend strongly on the concentration of Yb3+. The quadratic dependence of upconversion intensity on the excitation power indicates that the upconversion process is governed by two-photon absorption process.

Microwave hydrothermal synthesis and upconversion properties of Yb3+/Er3+ doped YVO4 nanoparticles.

PubMed

Kshetri, Yuwaraj K; Regmi, Chhabilal; Kim, Hak-Soo; Lee, Soo Wohn; Kim, Tae-Ho

2018-05-18

Yb 3+ and Er 3+ doped YVO 4 (Yb 3+ /Er 3+ :YVO 4 ) nanoparticles with highly efficient near-infrared to visible upconversion properties have been synthesized by microwave hydrothermal process. Uniform-sized Yb 3+ /Er 3+ :YVO 4 nanoparticles were synthesized within 1 h at 140 °C which is relatively faster than the conventional hydrothermal process. Under 980 nm laser excitation, strong green and less strong red emissions are observed which are attributed to 2 H 11/2 , 4 S 3/2 to 4 I 15/2 and 4 F 9/2 to 4 I 15/2 transitions of Er 3+ respectively. The emission intensity is found to depend strongly on the concentration of Yb 3+ . The quadratic dependence of upconversion intensity on the excitation power indicates that the upconversion process is governed by two-photon absorption process.

Single-band upconversion nanoprobes for multiplexed simultaneous in situ molecular mapping of cancer biomarkers.

PubMed

Zhou, Lei; Wang, Rui; Yao, Chi; Li, Xiaomin; Wang, Chengli; Zhang, Xiaoyan; Xu, Congjian; Zeng, Aijun; Zhao, Dongyuan; Zhang, Fan

2015-04-24

The identification of potential diagnostic markers and target molecules among the plethora of tumour oncoproteins for cancer diagnosis requires facile technology that is capable of quantitatively analysing multiple biomarkers in tumour cells and tissues. Diagnostic and prognostic classifications of human tumours are currently based on the western blotting and single-colour immunohistochemical methods that are not suitable for multiplexed detection. Herein, we report a general and novel method to prepare single-band upconversion nanoparticles with different colours. The expression levels of three biomarkers in breast cancer cells were determined using single-band upconversion nanoparticles, western blotting and immunohistochemical technologies with excellent correlation. Significantly, the application of antibody-conjugated single-band upconversion nanoparticle molecular profiling technology can achieve the multiplexed simultaneous in situ biodetection of biomarkers in breast cancer cells and tissue specimens and produce more accurate results for the simultaneous quantification of proteins present at low levels compared with classical immunohistochemical technology.

Up-conversion luminescence properties and energy transfer of Tm{sup 3+}/Yb{sup 3+} co-doped BaLa{sub 2}ZnO{sub 5}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Jing; Mei, Lefu, E-mail: mlf@cugb.edu.cn; Deng, Junru

2015-11-15

Tm{sup 3+}/Yb{sup 3+} co-doped BaLa{sub 2}ZnO{sub 5} up-conversion (UC) phosphors were successfully synthesized by high temperature solid-state reaction method. The X-ray diffraction (XRD) results show that synthesized phosphor co-doped with 0.75% Tm/10% Yb has the optimum pure phase of BaLa{sub 2}ZnO{sub 5} among different co-doping concentrations. The structure of BaLa{sub 2}ZnO{sub 5}:0.75% Tm/10% Yb phosphor was refined by the Rietveld method and results show the decreased unit cell parameters and cell volume after doping Tm{sup 3+}/Yb{sup 3+}, indicating that Tm{sup 3+}/Yb{sup 3+} have successfully replaced La{sup 3+}. Under excitation at 980 nm, Tm{sup 3+}/Yb{sup 3+} co-doped BaLa{sub 2}ZnO{sub 5} phosphorsmore » present bright blue emission near 478 nm generated by the {sup 1}G{sub 4}→{sup 3}H{sub 6} transition and weak red emissions around 653 nm and 692 nm generated by the {sup 1}G{sub 4}→{sup 3}F{sub 4} and {sup 3}F{sub 3}→{sup 3}H{sub 6} transitions of Tm{sup 3+}, respectively. The UC luminescence properties of BaLa{sub 2}ZnO{sub 5} phosphors co-doped with different Tm{sup 3+}/Yb{sup 3+} concentrations were investigated, and the related UC mechanisms of Tm{sup 3+}/Yb{sup 3+} co-doped BaLa{sub 2}ZnO{sub 5} depending on pump power were studied in detail. - Graphical abstract: Up-conversion luminescence of BaLa{sub 2}ZnO{sub 5}:Tm{sup 3+}/Yb{sup 3+} and its crystal structure and up-conversion mechanisms. - Highlights: • Up-conversion phosphors BaLa{sub 2}ZnO{sub 5} co-doped with Tm{sup 3+}/Yb{sup 3+} were synthesized by high temperature solid-state reaction method. • The crystal structure of BaLa{sub 2}ZnO{sub 5} and the changes of cell parameters and volume of BaLa{sub 2}ZnO{sub 5} after doping Tm{sup 3+} and Yb{sup 3+} have been discussed. • Up-conversion luminescence properties and energy transfer between Tm{sup 3+} and Yb{sup 3+} in BaLa{sub 2}ZnO{sub 5} have been discussed in detail.« less

Enhancing light harvesting and charge transport in organic solar cells via integrating lanthanide-doped upconversation materials

NASA Astrophysics Data System (ADS)

Wang, Fei; Yang, Xiao-Yu; Niu, Meng-si; Feng, Lin; Lv, Cheng-kun; Zhang, Kang-ning; Bi, Peng-qing; Yang, Junliang; Hao, Xiao-Tao

2018-07-01

Irradiation of lanthanide-doped upconversion nanoparticles with infrared light can lead to the emission of visible light, which is subsequently absorbed by the organic photoactive layer resulting in the performance enhancement of organic solar cells (OSCs). In this work, OSCs based on poly (3-hexylthiophene) (P3HT) and Phenyl C61 butyric acid methyl ester (PC61BM) blending ytterbium(III), erbium(III) co-doped sodium yttrium fluoride (NaYF4: Yb3+, Er3+) nanoparticles were fabricated with inverted structures. The results indicated that the short current density (J sc) and fill factor were apparently enhanced from 8.60 mA cm‑2 to 9.31 mA cm‑2 and from 57.96% to 64.84%, respectively, leading to an increment of power conversion efficiency (PCE). The photocurrent improvement may have attributed to the additional absorption light generated from upconversion with 980 nm excitation. The active layers with upconversion nanoparticles were investigated to prove enhanced light harvesting, charge transport and energy transfer from upconversion nanoparticles to P3HT. A synergistic effect of broadening light harvesting, efficient energy transfer process, increased carrier mobility and enhanced exciton dissociation in the polymer bulk heterojunction may contribute to the performance enhancement.

Boosting the down-shifting luminescence of rare-earth nanocrystals for biological imaging beyond 1500 nm.

PubMed

Zhong, Yeteng; Ma, Zhuoran; Zhu, Shoujun; Yue, Jingying; Zhang, Mingxi; Antaris, Alexander L; Yuan, Jie; Cui, Ran; Wan, Hao; Zhou, Ying; Wang, Weizhi; Huang, Ngan F; Luo, Jian; Hu, Zhiyuan; Dai, Hongjie

2017-09-29

In vivo fluorescence imaging in the near-infrared region between 1500-1700 nm (NIR-IIb window) affords high spatial resolution, deep-tissue penetration, and diminished auto-fluorescence due to the suppressed scattering of long-wavelength photons and large fluorophore Stokes shifts. However, very few NIR-IIb fluorescent probes exist currently. Here, we report the synthesis of a down-conversion luminescent rare-earth nanocrystal with cerium doping (Er/Ce co-doped NaYbF 4 nanocrystal core with an inert NaYF 4 shell). Ce doping is found to suppress the up-conversion pathway while boosting down-conversion by ~9-fold to produce bright 1550 nm luminescence under 980 nm excitation. Optimization of the inert shell coating surrounding the core and hydrophilic surface functionalization minimize the luminescence quenching effect by water. The resulting biocompatible, bright 1550 nm emitting nanoparticles enable fast in vivo imaging of blood vasculature in the mouse brain and hindlimb in the NIR-IIb window with short exposure time of 20 ms for rare-earth based probes.Fluorescence imaging in the near-infrared window between 1500-1700 nm (NIR-IIb window) offers superior spatial resolution and tissue penetration depth, but few NIR-IIb probes exist. Here, the authors synthesize rare earth down-converting nanocrystals as promising fluorescent probes for in vivo imaging in this spectral region.

Synthesis and up-conversion luminescence of Er{sup 3+} and Y b{sup 3+} codoped nanocrystalline tetra- (KLaP{sub 4}O{sub 12}) and pentaphosphates (LaP{sub 5}O{sub 14})

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marciniak, L., E-mail: l.marciniak@int.pan.wroc.pl; Stefanski, M.; Tomala, R.

2015-09-07

The up-converting nanocrystals of KLa{sub 0.95}Er{sub 0.05}Y b{sub x}P{sub 4}O{sub 12} and La{sub 0.95−x}Er{sub 0.05}Y b{sub x}P{sub 5}O{sub 14} were prepared using co-precipitation method. The spectroscopic properties of these materials were investigated in a function of Y b{sup 3+} concentration. The up-conversion emission, power dependence of emission intensities, and the luminescence decay times were investigated. It was found that the green to red and {sup 2}H{sub 11/2} → {sup 4}I{sub 15/2} to {sup 4}S{sub 3/2} → {sup 4}I{sub 15/2} emission intensity ratio were strongly affected by the Y b{sup 3+} concentration. Moreover, the order of up-conversion emission and threshold powermore » rises up with Y b{sup 3+} concentration for {sup 4}S{sub 3/2} → {sup 4}I{sub 15/2} transition. The luminescence decay time of the {sup 4}S{sub 3/2} → {sup 4}I{sub 15/2} emission increases with Y b{sup 3+} concentration while the {sup 4}F{sub 9/2} → {sup 4}I{sub 15/2} emission is independent of dopant concentration. The influence of the Y b{sup 3+} concentration on the up-conversion emission intensities was discussed in terms of concentration dependent hetero looped photon avalanche process. A comparison of the up-conversion properties of KLa{sub 0.95}Er{sub 0.05}Y b{sub x}P{sub 4}O{sub 12} and La{sub 0.95−x}Er{sub 0.05}Y b{sub x}P{sub 5}O{sub 14} nanocrystals was presented.« less

Strong upconversion from Er3Al5O12 ceramic powders prepared by low temperature direct combustion synthesis

NASA Astrophysics Data System (ADS)

Maciel, Glauco S.; Rakov, Nikifor; Fokine, Michael; Carvalho, Isabel C. S.; Pinheiro, Carlos B.

2006-08-01

Crystalline ceramic powders of Er3Al5O12 were obtained by low temperature direct combustion synthesis. Irradiating the sample with a low-power continuous-wave infrared (1.48μm) diode laser led to ultraviolet, violet, blue, green, and red (380, 410, 456, 495, 525, 550, and 660nm) emissions. The strong upconversion luminescence appeared to the eyes as an intense green color. The presence of efficient four- and three-photon frequency upconversion processes makes this material an excellent candidate for use in photonic devices based on upconverter phosphors.

Fluorine-18-labeled Gd3+/Yb3+/Er3+ co-doped NaYF4 nanophosphors for multimodality PET/MR/UCL imaging.

PubMed

Zhou, Jing; Yu, Mengxiao; Sun, Yun; Zhang, Xianzhong; Zhu, Xingjun; Wu, Zhanhong; Wu, Dongmei; Li, Fuyou

2011-02-01

Molecular imaging modalities provide a wealth of information that is highly complementary and rarely redundant. To combine the advantages of molecular imaging techniques, (18)F-labeled Gd(3+)/Yb(3+)/Er(3+) co-doped NaYF(4) nanophosphors (NPs) simultaneously possessing with radioactivity, magnetic, and upconversion luminescent properties have been fabricated for multimodality positron emission tomography (PET), magnetic resonance imaging (MRI), and laser scanning upconversion luminescence (UCL) imaging. Hydrophilic citrate-capped NaY(0.2)Gd(0.6)Yb(0.18)Er(0.02)F(4) nanophosphors (cit-NPs) were obtained from hydrophobic oleic acid (OA)-coated nanoparticles (OA-NPs) through a process of ligand exchange of OA with citrate, and were found to be monodisperse with an average size of 22 × 19 nm. The obtained hexagonal cit-NPs show intense UCL emission in the visible region and paramagnetic longitudinal relaxivity (r(1) = 0.405 s(-1)·(mM)(-1)). Through a facile inorganic reaction based on the strong binding between Y(3+) and F(-), (18)F-labeled NPs have been fabricated in high yield. The use of cit-NPs as a multimodal probe has been further explored for T(1)-weighted MR and PET imaging in vivo and UCL imaging of living cells and tissue slides. The results indicate that (18)F-labeled NaY(0.2)Gd(0.6)Yb(0.18)Er(0.02) is a potential candidate as a multimodal nanoprobe for ultra-sensitive molecular imaging from the cellular scale to whole-body evaluation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Giant enhancement of upconversion in ultra-small Er³⁺/Yb³⁺:NaYF₄ nanoparticles via laser annealing.

PubMed

Bednarkiewicz, A; Wawrzynczyk, D; Gagor, A; Kepinski, L; Kurnatowska, M; Krajczyk, L; Nyk, M; Samoc, M; Strek, W

2012-04-13

Most of the synthesis routes of lanthanide-doped phosphors involve thermal processing which results in nanocrystallite growth, stabilization of the crystal structure and augmentation of luminescence intensity. It is of great interest to be able to transform the sample in a spatially localized manner, which may lead to many applications like 2D and 3D data storage, anti-counterfeiting protection, novel design bio-sensors and, potentially, to fabrication of metamaterials, 3D photonic crystals or plasmonic devices. Here we demonstrate irreversible spatially confined infrared-laser-induced annealing (LIA) achieved in a thin layer of dried colloidal solution of ultra-small ∼8 nm NaYF₄ nanocrystals (NCs) co-doped with 2% Er³⁺ and 20% Yb³⁺ ions under a localized tightly focused beam from a continuous wave 976 nm medium power laser diode excitation. The LIA results from self-heating due to non-radiative relaxation accompanying the NIR laser energy upconversion in lanthanide ions. We notice that localized LIA appears at optical power densities as low as 15.5 kW cm⁻² (∼354 ± 29 mW) threshold in spots of 54 ± 3 µm diameter obtained with a 10 × microscope objective. In the course of detailed studies, a complete recrystallization to different phases and giant 2-3 order enhancement in luminescence yield is found. Our results are highly encouraging and let us conclude that the upconverting ultra-small lanthanide-doped nanophosphors are particularly promising for direct laser writing applications.

Giant enhancement of upconversion in ultra-small Er3+/Yb3+:NaYF4 nanoparticles via laser annealing

NASA Astrophysics Data System (ADS)

Bednarkiewicz, A.; Wawrzynczyk, D.; Gagor, A.; Kepinski, L.; Kurnatowska, M.; Krajczyk, L.; Nyk, M.; Samoc, M.; Strek, W.

2012-04-01

Most of the synthesis routes of lanthanide-doped phosphors involve thermal processing which results in nanocrystallite growth, stabilization of the crystal structure and augmentation of luminescence intensity. It is of great interest to be able to transform the sample in a spatially localized manner, which may lead to many applications like 2D and 3D data storage, anti-counterfeiting protection, novel design bio-sensors and, potentially, to fabrication of metamaterials, 3D photonic crystals or plasmonic devices. Here we demonstrate irreversible spatially confined infrared-laser-induced annealing (LIA) achieved in a thin layer of dried colloidal solution of ultra-small ˜8 nm NaYF4 nanocrystals (NCs) co-doped with 2% Er3+ and 20% Yb3+ ions under a localized tightly focused beam from a continuous wave 976 nm medium power laser diode excitation. The LIA results from self-heating due to non-radiative relaxation accompanying the NIR laser energy upconversion in lanthanide ions. We notice that localized LIA appears at optical power densities as low as 15.5 kW cm-2 (˜354 ± 29 mW) threshold in spots of 54 ± 3 µm diameter obtained with a 10 × microscope objective. In the course of detailed studies, a complete recrystallization to different phases and giant 2-3 order enhancement in luminescence yield is found. Our results are highly encouraging and let us conclude that the upconverting ultra-small lanthanide-doped nanophosphors are particularly promising for direct laser writing applications.

[Multiply upconversion emission in oxyfluoride ceramics].

PubMed

Xiao, Si-guo; Yang, Xiao-liang; Liu, Zhen-wei

2003-02-01

Oxyfluoride ceramics with the host composition of SiO2 and PbF2 have been prepared. X-ray diffraction analysis of the ceramics revealed that fluoride type beta-PbF2 solid solution regions are precipitated in the glass matrix. Rare earth ions in the beta-PbF2 solid solution show highly efficient upconversion performance due to the very small multi-phonon relaxation rates. Eight upconversion emission bands whose central wavelength are 846, 803, 665, 549, 523, 487, 456 and 411 nm have been observed when the sample was excited with 930 nm diode light. Four possible energy transfer processes between Er3+ and Yb3+ cause the electronic population of high energy level of Er3+ and realize the abound upconversion luminescence bands.

Study of upconversion fluorescence property of novel Er3+/Yb3+ co-doped tellurite glasses.

PubMed

Xu, Tie-Feng; Li, Guang-Po; Nie, Qiu-Hua; Shen, Xiang

2006-06-01

Er3+/Yb3+ co-doped TeO2-B2O3-Nb2O5-ZnO (TBN) glasses were prepared. The absorption spectra and upconversion luminescence spectra of TBN glasses were measured and analyzed. The upconversion emission bands centered at 530, 546 and 658 nm were observed under the excitation at 975 nm, corresponding to the transitions of 2H11/2-->4I15/2, 4S3/2-->4I15/2 and 4F9/2-->4I15/2 respectively. The ratio of red emission to green emission increases with an increasing of Yb3+ ions concentration. According to the quadratic dependence on excitation power, the possible upconversion mechanisms and processes were discussed.

Er3+ -doped anatase TiO2 nanocrystals: crystal-field levels, excited-state dynamics, upconversion, and defect luminescence.

PubMed

Luo, Wenqin; Fu, Chengyu; Li, Renfu; Liu, Yongsheng; Zhu, Haomiao; Chen, Xueyuan

2011-11-04

A comprehensive survey of electronic structure and optical properties of rare-earth ions embedded in semiconductor nanocrystals (NCs) is of vital importance for their potential applications in areas as diverse as luminescent bioprobes, lighting, and displays. Er3+ -doped anatase TiO2 NCs, synthesized via a facile sol-gel solvothermal method, exhibit intense and well-resolved intra-4f emissions of Er3+ . Crystal-field (CF) spectra of Er3+ in TiO2 NCs are systematically studied by means of high-resolution emission and excitation spectra at 10-300 K. The CF analysis of Er3+ assuming a site symmetry of C(2v) yields a small root-mean-square deviation of 25.1 cm(-1) and reveals the relatively large CF strength (549 cm(-1) ) of Er3+, thus verifying the rationality of the C(2v) symmetry assignment of Er3+ in anatase TiO2 NCs. Based on a simplified thermalization model for the temperature-dependent photoluminescence (PL) dynamics from (4) S(3/2) , the intrinsic radiative luminescence lifetimes of (4) S(3/2) and (2) H(11/2) are experimentally determined to be 3.70 and 1.73 μs, respectively. Green and red upconversion (UC) luminescence of Er3+ can be achieved upon laser excitation at 974.5 nm. The UC intensity of Er3+ in Yb/Er-codoped NCs is found to be about five times higher than that of Er-singly-doped counterparts as a result of efficient Yb3+ sensitization and energy transfer upconversion (ETU) evidenced by its distinct UC luminescence dynamics. Furthermore, the origin of defect luminescence is revealed based on the temperature-dependent PL spectra upon excitation above the TiO2 bandgap at 325 nm. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Upconversion luminescence of CsScF4 crystals doped with erbium and ytterbium

NASA Astrophysics Data System (ADS)

Ikonnikov, D. A.; Voronov, V. N.; Molokeev, M. S.; Aleksandrovsky, A. S.

2016-10-01

Tetragonal CsScF4 crystals doped with (5 at.%) Er and Er/Yb (0.5 at.%/5 at.%) are grown and their crystal structure is determined to belong to Pmmn space group. Er and Yb ions are shown to occupy distorted octahedral Sc sites with the center of inversion. Bright visible upconversion luminescence was observed under 970-980 nm pumping with red (4F9/2), yellow (4S3/2) and green (2H11/2) bands of comparable intensity. UCL tuning curves maximize at 972 nm (CSF:Er) and at 969.7 nm (CSF:Er,Yb) pumping wavelengths. Different ratios between yellow-green and red luminescence intensities in CSF:Er and CSF:Er, Yb are explained by contribution of cross-relaxation in CSF:Er UCL. UC in CSF:Er is a three stage process while UC in CSF:Er, Yb is a two stage process. The peculiarities of power dependences are explained by the power-dependent repopulation between starting levels of UC.

Lanthanide-doped NaScF4 nanoprobes: crystal structure, optical spectroscopy and biodetection.

PubMed

Ai, Yu; Tu, Datao; Zheng, Wei; Liu, Yongsheng; Kong, Jintao; Hu, Ping; Chen, Zhuo; Huang, Mingdong; Chen, Xueyuan

2013-07-21

Trivalent lanthanide ions (Ln(3+))-doped inorganic nanoparticles (NPs) as potential luminescent bioprobes have been attracting tremendous interest because of their unique upconversion (UC) and downconversion (DC) luminescence properties. NaScF4, as an important host material, has been rarely reported and its crystal structure remains unclear. Herein, based on the single crystal X-ray diffraction, the space group of NaScF4 crystals was determined to be P31 containing multiple sites of Sc(3+) with crystallographic site symmetry of C1, which was verified by high-resolution photoluminescence spectroscopy of Eu(3+) at low temperature (10 K). Furthermore, monodisperse and size-controllable NaScF4:Ln(3+) NPs were synthesized via a facile thermal decomposition method. The biotinylated NaScF4:Er(3+)/Yb(3+) NPs were demonstrated for their applications as a heterogeneous UC luminescence bioprobe to detect avidin with a detection limit of 180 pM. After bioconjugation with amino-terminal fragment (ATF) of urokinase plasminogen activator (uPA), NaScF4:Ln(3+) NPs also exhibited specific recognition of cancer cells overexpressed with uPA receptor (uPAR, an important marker of tumor biology and metastasis), showing great potentials in tumor-targeted bioimaging.

Multifunctional Optical Sensors for Nanomanometry and Nanothermometry: High-Pressure and High-Temperature Upconversion Luminescence of Lanthanide-Doped Phosphates-LaPO4/YPO4:Yb3+-Tm3.

PubMed

Runowski, Marcin; Shyichuk, Andrii; Tymiński, Artur; Grzyb, Tomasz; Lavín, Víctor; Lis, Stefan

2018-05-23

Upconversion luminescence of nano-sized Yb 3+ and Tm 3+ codoped rare earth phosphates, that is, LaPO 4 and YPO 4 , has been investigated under high-pressure (HP, up to ∼25 GPa) and high-temperature (293-773 K) conditions. The pressure-dependent luminescence properties of the nanocrystals, that is, energy red shift of the band centroids, changes of the band ratios, shortening of upconversion lifetimes, and so forth, make the studied nanomaterials suitable for optical pressure sensing in nanomanometry. Furthermore, thanks to the large energy difference (∼1800 cm -1 ), the thermalized states of Tm 3+ ions are spectrally well-separated, providing high-temperature resolution, required in optical nanothermometry. The temperature of the system containing such active nanomaterials can be determined on the basis of the thermally induced changes of the Tm 3+ band ratio ( 3 F 2,3 → 3 H 6 / 3 H 4 → 3 H 6 ), observed in the emission spectra. The advantage of such upconverting optical sensors is the use of near-infrared light, which is highly penetrable for many materials. The investigated nanomanometers/nanothermometers have been successfully applied, as a proof-of-concept of a novel bimodal optical gauge, for the determination of the temperature of the heated system (473 K), which was simultaneously compressed under HP (1.5 and 5 GPa).

Growth and optical properties of Pr,Yb-codoped KY 3F 10 fluoride single crystals for up-conversion visible luminescence

NASA Astrophysics Data System (ADS)

Kim, Kyoung Jin; Jouini, Anis; Yoshikawa, Akira; Simura, Rayko; Boulon, Georges; Fukuda, Tsuguo

2007-02-01

We investigate different ways to realize laser emission from (Pr 3+) 3P J=0,1,2 levels by pump sources other than the common argon and excimer-dye laser. The use of infrared (IR) laser diodes in combination with intra- and inter-ionic energy transfer processes (up-conversion) could be an efficient solution towards laser oscillation. Pr 3+,Yb 3+-codoped KY 3F 10 (Pr, Yb:KYF) single crystals were successfully grown by the micro-pulling-down (μ-PD) method. The crystals were transparent with a slightly greenish color, 2.0-2.5 mm in diameter, 20-30 mm in length and free from visible inclusions and cracks. Effective segregation coefficients of Pr and Yb in KYF were studied by means of absorption and chemical analysis. Strong visible emission via selective IR pumping with λ=975 nm and up-conversion excitation were obtained in Pr, Yb:KYF at room temperature (RT). Luminescence measurements have been carried out and the decay kinetics of the Pr 3+ visible emissions was investigated by room temperature time-resolved spectra.

Highly efficient saturated visible up-conversion photoluminescent Y 2 O 3 :Er 3+ microspheres pumped with a 1.55 μm laser diode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Jinbo; Wu, Lili; Zhang, Chuanjiang

2017-01-01

Highly efficient saturation up-conversion (UC) luminescent Y2O3:Er3+ microspheres have been successfully prepared via a hydrothermal-homogeneous precipitation method. Bright visible luminescence can be clearly seen with a 1.55 mu m laser diode excitation power as low as similar to 0.03 W cm(-2). The up-conversion (UC) emission spectra indicate that the strongest red emission with a peak situated at similar to 660 nm originated from the I-4(9/2) -> I-4(15/2) transition of Er3+. The peaks situated at similar to 520 and 550 nm can be assigned to the transition from H-2(11/2)/S-4(3/2) state to the ground state of Er3+. The high efficient saturation up-conversionmore » emission is related to the highly crystalline structure. These results indicate a new way to enhance UC radiation in rare-earth ion-doped materials prepared using a hydrothermal-homogeneous precipitation method.« less

Development of zirconia based phosphors for application in lighting and as luminescent bioprobes =

NASA Astrophysics Data System (ADS)

Soares, Maria Rosa Nunes

The strong progress evidenced in photonic and optoelectronic areas, accompanied by an exponential development in the nanoscience and nanotechnology, gave rise to an increasing demand for efficient luminescent materials with more and more exigent characteristics. In this field, wide band gap hosts doped with lanthanide ions represent a class of luminescent materials with a strong technological importance. Within wide band gap material, zirconia owns a combination of physical and chemical properties that potentiate it as an excellent host for the aforementioned ions, envisaging its use in different areas, including in lighting and optical sensors applications, such as pressure sensors and biosensors. Following the demand for outstanding luminescent materials, there is also a request for fast, economic and an easy scale-up process for their production. Regarding these demands, laser floating zone, solution combustion synthesis and pulsed laser ablation in liquid techniques are explored in this thesis for the production of single crystals, nanopowders and nanoparticles of lanthanides doped zirconia based hosts. Simultaneously, a detailed study of the morphological, structural and optical properties of the produced materials is made. The luminescent characteristics of zirconia and yttria stabilized zirconia (YSZ) doped with different lanthanide ions (Ce3+ (4f1), Pr3+ (4f2), Sm3+ (4f5), Eu3+ (4f6), Tb3+ (4f8), Dy3+ (4f9), Er3+ (4f11), Tm3+ (4f12), Yb3+ (4f13)) and co-doped with Er3+,Yb3+ and Tm3+,Yb3+ are analysed. Besides the Stokes luminescence, the anti- Stokes emission upon infrared excitation (upconversion and black body radiation) is also analysed and discussed. The comparison of the luminescence characteristics in materials with different dimensions allowed to analyse the effect of size in the luminescent properties of the dopant lanthanide ions. The potentialities of application of the produced luminescent materials in solid state light, biosensors and pressure sensors are explored taking into account their studied characteristics.

Photon upconversion towards applications in energy conversion and bioimaging

NASA Astrophysics Data System (ADS)

Sun, Qi-C.; Ding, Yuchen C.; Sagar, Dodderi M.; Nagpal, Prashant

2017-12-01

The field of plasmonics can play an important role in developing novel devices for application in energy and healthcare. In this review article, we consider the progress made in design and fabrication of upconverting nanoparticles and metal nanostructures for precisely manipulating light photons, with a wavelength of several hundred nanometers, at nanometer length scales, and describe how to tailor their interactions with molecules and surfaces so that two or more lower energy photons can be used to generate a single higher energy photon in a process called photon upconversion. This review begins by introducing the current state-of-the-art in upconverting nanoparticle synthesis and achievements in color tuning and upconversion enhancement. Through understanding and tailoring physical processes, color tuning and strong upconversion enhancement have been demonstrated by coupling with surface plasmon polariton waves, especially for low intensity or diffuse infrared radiation. Since more than 30% of incident sunlight is not utilized in most photovoltaic cells, this photon upconversion is one of the promising approaches to break the so-called Shockley-Queisser thermodynamic limit for a single junction solar cell. Furthermore, since the low energy photons typically cover the biological window of optical transparency, this approach can also be particularly beneficial for novel biosensing and bioimaging techniques. Taken together, the recent research boosts the applications of photon upconversion using designed metal nanostructures and nanoparticles for green energy, bioimaging, and therapy.

Rich stochastic dynamics of co-doped Er:Yb fluorescence upconversion nanoparticles in the presence of thermal, non-conservative, harmonic and optical forces

NASA Astrophysics Data System (ADS)

Nome, Rene A.; Sorbello, Cecilia; Jobbágy, Matías; Barja, Beatriz C.; Sanches, Vitor; Cruz, Joyce S.; Aguiar, Vinicius F.

2017-03-01

The stochastic dynamics of individual co-doped Er:Yb upconversion nanoparticles (UCNP) were investigated from experiments and simulations. The UCNP were characterized by high-resolution scanning electron microscopy, dynamic light scattering, and zeta potential measurements. Single UCNP measurements were performed by fluorescence upconversion micro-spectroscopy and optical trapping. The mean-square displacement (MSD) from single UCNP exhibited a time-dependent diffusion coefficient which was compared with Brownian dynamics simulations of a viscoelastic model of harmonically bound spheres. Experimental time-dependent two-dimensional trajectories of individual UCNP revealed correlated two-dimensional nanoparticle motion. The measurements were compared with stochastic trajectories calculated in the presence of a non-conservative rotational force field. Overall, the complex interplay of UCNP adhesion, thermal fluctuations and optical forces led to a rich stochastic behavior of these nanoparticles.

Hydrogels dispersed by doped rare earth fluoride nanocrystals: ionic liquid dispersion and down/up-conversion luminescence.

PubMed

Yan, Zhi-Yuan; Jia, Li-Ping; Yan, Bing

2014-01-01

Two typical kinds of rare earth fluoride nanocrystals codoped with rare earth ions (Eu(3+) and Tm(3+)/Er(3+),Yb(3+)) are synthesized and dispersed in ionic liquid compound (1-chlorohexane-3-methylimidazolium chloride, abbreviated as [C6mim][Cl]). Assisted by agarose, the luminescent hydrogels are prepared homogeneously. The down/up-conversion luminescence of these hydrogels can be realized for the dispersed rare earth fluoride nanocrystals. The results provide a strategy to prepare luminescent (especially up-conversion luminescent) hydrogels with ionic liquid to disperse rare earth fluoride nanocrystals. Copyright © 2013 Elsevier B.V. All rights reserved.

Chromium complexes for luminescence, solar cells, photoredox catalysis, upconversion, and phototriggered NO release

PubMed Central

Büldt, Laura A.

2017-01-01

Some complexes of Cr(iii) and Cr(0) have long been known to exhibit interesting photophysical and photochemical properties, but in the past few years important conceptual progress was made. This Perspective focuses on the recent developments of Cr(iii) complexes as luminophores and dyes for solar cells, their application in photoredox catalysis, their use as sensitizers in upconversion processes, and their performance as photochemical nitric oxide sources. The example of a luminescent Cr(0) isocyanide complex illustrates the possibility of obtaining photoactive analogues of d6 metal complexes that are commonly made from precious metals such as Ru(ii) or Ir(iii). The studies highlighted herein illustrate the favorable excited-state properties of robust first-row transition metal complexes with broad application potential. PMID:29163886

Chromium complexes for luminescence, solar cells, photoredox catalysis, upconversion, and phototriggered NO release.

PubMed

Büldt, Laura A; Wenger, Oliver S

2017-11-01

Some complexes of Cr(iii) and Cr(0) have long been known to exhibit interesting photophysical and photochemical properties, but in the past few years important conceptual progress was made. This Perspective focuses on the recent developments of Cr(iii) complexes as luminophores and dyes for solar cells, their application in photoredox catalysis, their use as sensitizers in upconversion processes, and their performance as photochemical nitric oxide sources. The example of a luminescent Cr(0) isocyanide complex illustrates the possibility of obtaining photoactive analogues of d 6 metal complexes that are commonly made from precious metals such as Ru(ii) or Ir(iii). The studies highlighted herein illustrate the favorable excited-state properties of robust first-row transition metal complexes with broad application potential.

Smart pH-responsive upconversion nanoparticles for enhanced tumor cellular internalization and near-infrared light-triggered photodynamic therapy.

PubMed

Wang, Sheng; Zhang, Lei; Dong, Chunhong; Su, Lin; Wang, Hanjie; Chang, Jin

2015-01-01

A smart pH-responsive photodynamic therapy system based on upconversion nanoparticle loaded PEG coated polymeric lipid vesicles (RB-UPPLVs) was designed and prepared. These RB-UPPLVs which are promising agents for deep cancer photodynamic therapy applications can achieve enhanced tumor cellular internalization and near-infrared light-triggered photodynamic therapy.

Enhancement of luminescence properties in Er3+ doped TeO2-Na2O-PbX (X=O and F) ternary glasses.

PubMed

Kumar, Kaushal; Rai, S B; Rai, D K

2007-04-01

An enhancement of luminescence properties in Er3+ doped ternary glasses is observed on the addition of PbO/PbF2. The infrared to visible upconversion emission bands are observed at 410, 525, 550 and 658 nm, due to the 2H9/2-->4I15/2, 2H11/2-->4I15/2, 4S3/2-->4I15/2, 4F9/2-->4I15/2 transitions respectively, on excitation with 797 nm laser line. A detailed study reveals that the 2H9/2-->4I15/2 transition arises due to three step upconversion process while other transitions arise due to two step absorption. On excitation with 532 nm radiation, ultraviolet and violet upconversion bands centered at 380, 404, 410 and 475 nm wavelengths are observed along with one photon luminescence bands at 525, 550, 658 and 843 nm wavelengths. These bands are found due to the 4G11/2-->4I15/2, 2P3/2-->4I13/2, 2H9/2-->4I15/2, 2P3/2-->4I11/2, 2H11/2-->4I15/2, 4S3/2-->4I15/2, 4F9/2-->4I15/2 and 4S3/2-->4I13/2 transitions, respectively. Though incorporation of PbO and PbF2 both enhances fluorescence intensities however, PbF2 content has an important influence on upconversion luminescence emission. The incorporation of PbF2 enhances the red emission (658 nm) intensity by 1.5 times and the violet emission (410 nm) intensity by 2.0 times. A concentration dependence study of fluorescence reveals the rapid increase in the red (4F9/2-->4I15/2) emission intensity relative to the green (4S3/2-->4I15/2) emission with increase in the Er3+ ion concentration. This behaviour has been explained in terms of an energy transfer by relaxation between excited ions.

Spatial height directed microfluidic synthesis of transparent inorganic upconversion nano film

NASA Astrophysics Data System (ADS)

Liu, Xiaoxia; Zhu, Cheng; Liao, Wei; Jin, Junyang; Ni, Yaru; Lu, Chunhua; Xu, Zhongzi

2017-11-01

A microfluidic-based synthesis of an inorganic upconversion nano film has been developed with a large area of dense-distributed NaYF4 crystal grains in a silica glass micro-reactor and the film exhibits high transparence, strong upconversion luminescence and robust adhesion with the substrate. The spatial heights of micro-reactors are tuned between 31 and 227 mm, which can regulate flow regimes. The synergistic effect of spatial height and fluid regime is put forward, which influences diffusion paths and assembly ways of different precursor molecules and consequently directs final distributions and morphologies of crystal grains, as well as optical properties due to diversity of surface and thickness of films. The spatial height of 110 mm is advantageous for high transmittance of upconversion film due to the flat surface and appropriate film thickness of 67 nm. The height of 150 mm is in favor of uniform distribution of upconversion fluorescence and achieving the strongest fluorescence due to minimized optical loss. Such a transparent upconversion film with a large area of uniform distribution is promising to promote the application of upconversion materials and spatial height directed microfluidic regime have a certain significance on many microfluidic synthesis.

Down- and up-conversion luminescent carbon dot fluid: inkjet printing and gel glass fabrication

NASA Astrophysics Data System (ADS)

Wang, Fu; Xie, Zheng; Zhang, Bing; Liu, Yun; Yang, Wendong; Liu, Chun-Yan

2014-03-01

Room temperature liquid-like nanoparticles have emerged as an exciting new research and development area, because their properties could be tailored over a broad range by manipulating geometric and chemical characteristics of the inorganic core and organic canopy. However, related applications are rarely reported due to the multi-step synthesis process and potential toxicity of cadmium based nanomaterials. In this study, we prepared inexpensive and eco-friendly carbon dot fluid by the direct thermal decomposition method. The carbon dot fluid can be excited from UV to near infrared light, and can be prepared as highly concentrated luminescent ink or incorporated into sol-gel derived organically modified silicate glass, suggesting that it has great application potential in the field of printable electronics, solid state lighting and so on.Room temperature liquid-like nanoparticles have emerged as an exciting new research and development area, because their properties could be tailored over a broad range by manipulating geometric and chemical characteristics of the inorganic core and organic canopy. However, related applications are rarely reported due to the multi-step synthesis process and potential toxicity of cadmium based nanomaterials. In this study, we prepared inexpensive and eco-friendly carbon dot fluid by the direct thermal decomposition method. The carbon dot fluid can be excited from UV to near infrared light, and can be prepared as highly concentrated luminescent ink or incorporated into sol-gel derived organically modified silicate glass, suggesting that it has great application potential in the field of printable electronics, solid state lighting and so on. Electronic supplementary information (ESI) available: Details of FTIR, XRD and DLS of CDF, optical properties of CDF, TEM images of other obtained products, luminescent spectra of CDF at different temperatures, and the optical photographs of CDF inks and silica glasses with different concentrations under normal, UV and 800 nm light. See DOI: 10.1039/c3nr05869g

Optical transitions of Ho(3+) in oxyfluoride glasses and upconversion luminescence of Ho(3+)/Yb(3+)-codoped oxyfluoride glasses.

PubMed

Feng, Li; Wu, Yinsu

2015-05-05

Optical properties of Ho(3+)-doped SiO2-BaF2-ZnF2 glasses have been investigated on the basis of the Judd-Ofelt theory. Judd-Ofelt intensity parameters, radiative transition probabilities, fluorescence branching ratios and radiative lifetimes have been calculated for different glass compositions. Upconversion emissions were observed in Ho(3+)/Yb(3+)-codoped SiO2-BaF2-ZnF2 glasses under 980nm excitation. The effects of composition, concentration of the doping ions, and excitation pump power on the upconversion emissions were also systematically studied. Copyright © 2015 Elsevier B.V. All rights reserved.

Optical transitions of Tm3+ in oxyfluoride glasses and compositional and thermal effect on upconversion luminescence of Tm3+/Yb3+-codoped oxyfluoride glasses.

PubMed

Feng, Li; Wu, Yinsu; Liu, Zhuo; Guo, Tao

2014-01-24

Optical properties of Tm(3+)-doped SiO2-BaF2-ZnF2 glasses have been investigated on the basis of the Judd-Ofelt theory. Judd-Ofelt intensity parameters, radiative transition probabilities, fluorescence branching ratios and radiative lifetimes have been calculated for different glass compositions. Upconversion emissions were observed in Tm(3+)/Yb(3+)-codoped SiO2-BaF2-ZnF2 glasses under 980 nm excitation. The effects of composition, concentration of the doping ions, temperature, and excitation pump power on the upconversion emissions were also systematically studied. Copyright © 2013 Elsevier B.V. All rights reserved.

Pyropheophorbide A and c(RGDyK) comodified chitosan-wrapped upconversion nanoparticle for targeted near-infrared photodynamic therapy.

PubMed

Zhou, Aiguo; Wei, Yanchun; Wu, Baoyan; Chen, Qun; Xing, Da

2012-06-04

Near-infrared (NIR)-to-visible upconversion nanoparticle (UCNP) has shown promising prospects in photodynamic therapy (PDT) as a drug carrier or energy donor. In this work, a photosensitizer pyropheophorbide a (Ppa) and RGD peptide c(RGDyK) comodified chitosan-wrapped NaYF(4):Yb/Er upconversion nanoparticle UCNP-Ppa-RGD was developed for targeted near-infrared photodynamic therapy. The properties of UCNP-Ppa-RGD, such as morphology, stability, optical spectroscopy and singlet oxygen generation efficiency, were investigated. The results show that covalently linked pyropheophorbide a molecule not only is stable but also retains its spectroscopic and functional properties. In vitro studies confirm a stronger targeting specificity of UCNP-Ppa-RGD to integrin α(v)β(3)-positive U87-MG cells compared with that in the corresponding negative group. The photosensitizer-attached nanostructure exhibited low dark toxicity and high phototoxicity against cancer cells upon 980 nm laser irradiation at an appropriate dosage. These results represent the first demonstration of a highly stable and efficient photosensitizer modified upconversion nanostructure for targeted near-infrared photodynamic therapy of cancer cells. The novel UCNP-Ppa-RGD nanoparticle may provide a powerful alternative for near-infrared photodynamic therapy with an improved tumor targeting specificity.

Rare Earth Ion-Doped Upconversion Nanocrystals: Synthesis and Surface Modification

PubMed Central

Chang, Hongjin; Xie, Juan; Zhao, Baozhou; Liu, Botong; Xu, Shuilin; Ren, Na; Xie, Xiaoji; Huang, Ling; Huang, Wei

2014-01-01

The unique luminescent properties exhibited by rare earth ion-doped upconversion nanocrystals (UCNPs), such as long lifetime, narrow emission line, high color purity, and high resistance to photobleaching, have made them widely used in many areas, including but not limited to high-resolution displays, new-generation information technology, optical communication, bioimaging, and therapy. However, the inherent upconversion luminescent properties of UCNPs are influenced by various parameters, including the size, shape, crystal structure, and chemical composition of the UCNPs, and even the chosen synthesis process and the surfactant molecules used. This review will provide a complete summary on the synthesis methods and the surface modification strategies of UCNPs reported so far. Firstly, we summarize the synthesis methodologies developed in the past decades, such as thermal decomposition, thermal coprecipitation, hydro/solvothermal, sol-gel, combustion, and microwave synthesis. In the second part, five main streams of surface modification strategies for converting hydrophobic UCNPs into hydrophilic ones are elaborated. Finally, we consider the likely directions of the future development and challenges of the synthesis and surface modification, such as the large-scale production and actual applications, stability, and so on, of the UCNPs. PMID:28346995

White up-conversion emission in Ho3+/Tm3+/Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals

NASA Astrophysics Data System (ADS)

Li, Chenxia; Xu, Shiqing; Ye, Rengguang; Deng, Degang; Hua, Youjie; Zhao, Shilong; Zhuang, Songlin

2011-04-01

Ho3+/Tm3+/Yb3+ tri-doped glass ceramics with white light emitting have been developed and demonstrated. Pumped by 980 nm laser diode (LD), intensive red, green and blue up-conversions (UC) were obtained. The green emission is assigned to Ho3+ ion and the blue emission is assigned to Tm3+ ion, whereas the red emission is the combination contribution of the Ho3+ and Tm3+ ions. The RGB intensities could be adjusted by tuning the rare-earth ion concentration and pump power intensity. Thus, multicolor of the luminescence, including perfect white light with CIE-X=0.329 and CIE-Y=0.342 in the 1931 CIE chromaticity diagram can be obtained in 0.15 Ho3+/0.2Tm3+/3Yb3+ tri-doped glass ceramics embedding BaF2 nanocrystals pumped by a single infrared laser diode source of 980 nm at 500 mW. The up-conversion luminescence mechanism of Yb3+ sensitize Ho3+ and Tm3+ ions and the energy transfer from Ho3+ to Tm3+ in oxy-fluoride silicate glass ceramics were analyzed.

Tuning upconversion luminescence of LiYF4:Yb3+,Er3+/Tm3+/Ho3+ microcrystals synthesized through a molten salt process.

PubMed

Niu, Na; He, Fei; Wang, Liuzhen; Wang, Lin; Wang, Yan; Gai, Shili; Yang, Piaoping

2014-05-01

In this paper, well-defined tetragonal-phase LiYF4:Yb3+,Er3+/Tm3+/Ho3+ micro-crystals with octahedral morphology were successfully prepared through a surfactant-free molten salt process for the first time. By gradually increasing the LiF content in the NaNO3-KNO3 reaction medium, the crystal phase transforms from a mixture of YF3 and LiYF4 to pure tetragonal-phase LiYF4. The possible formation process for the phase and morphology evolution is also presented. Moreover, upon 980 nm laser diode (LD) excitation, the lanthanide ions (Yb3+, Er3+/Tm3+/Ho3+) doped LiYF4 crystals exhibit intense upconversion emission lights. By tuning the sensitizer concentrations of Yb3+ ions in LiYF4:Yb3+,Er3+, the relative intensities of green and red emissions can be precisely adjusted under single wavelength excitation. Consequently, multicolor upconversion emissions can be obtained. On the other hand, UC mechanisms were also given based on the emission spectra and the plot of luminescence intensity to pump power.

Paradigms and challenges for bioapplication of rare earth upconversion luminescent nanoparticles: small size and tunable emission/excitation spectra.

PubMed

Sun, Ling-Dong; Wang, Ye-Fu; Yan, Chun-Hua

2014-04-15

Rare earth (RE) materials, which are excited in the ultraviolet and emit in the visible light spectrum, are widely used as phosphors for lamps and displays. In the 1960's, researchers reported an abnormal emission phenomenon where photons emitted from a RE element carried more energy than those absorbed, owing to the sequential energy transfer between two RE ions--Yb(3+)-sensitized Er(3+) or Tm(3+)--in the solid state. After further study, researchers named this abnormal emission phenomenon upconversion (UC) emission. More recent approaches take advantage of solution-based synthesis, which allows creation of homogenous RE nanoparticles (NPs) with controlled size and structure that are capable of UC emission. Such nanoparticles are useful for many applications, especially in biology. For these applications, researchers seek small NPs with high upconversion emission intensity. These UCNPs have the potential to have multicolor and tunable emissions via various activators. A vast potential for future development remains by developing molecular antennas and energy transfer within RE ions. We expect UCNPs with optimized spectra behavior to meet the increasing demand of potential applications in bioimaging, biological detection, and light conversion. This Account focuses on efforts to control the size and modulate the spectra of UCNPs. We first review efforts in size control. One method is careful control of the synthesis conditions to manipulate particle nucleation and growth, but more recently researchers have learned that the doping conditions can affect the size of UCNPs. In addition, constructing homogeneous core/shell structures can control nanoparticle size by adjusting the shell thickness. After reviewing size control, we consider how diverse applications impose different requirements on excitation and/or emission photons and review recent developments on tuning of UC spectral profiles, especially the extension of excitation/emission wavelengths and the adjustment and purification of emission colors. We describe strategies that employ various dopants and others that build rationally designed nanostructures and nanocomposites to meet these goals. As the understanding of the energy transfer in the UC process has improved, core/shell structures have been proved useful for simultaneous tuning of excitation and emission wavelengths. Finally, we present a number of typical examples to highlight the upconverted emission in various applications, including imaging, detection, and sensing. We believe that with deeper understanding of emission phenomena and the ability to tune spectral profiles, UCNPs could play an important role in light conversion studies and applications.

Realizing up-conversion fluorescence tuning in lanthanide-doped nanocrystals by femtosecond pulse shaping method

PubMed Central

Zhang, Shian; Yao, Yunhua; Shuwu, Xu; Liu, Pei; Ding, Jingxin; Jia, Tianqing; Qiu, Jianrong; Sun, Zhenrong

2015-01-01

The ability to tune color output of nanomaterials is very important for their applications in laser, optoelectronic device, color display and multiplexed biolabeling. Here we first propose a femtosecond pulse shaping technique to realize the up-conversion fluorescence tuning in lanthanide-doped nanocrystals dispersed in the glass. The multiple subpulse formation by a square phase modulation can create different excitation pathways for various up-conversion fluorescence generations. By properly controlling these excitation pathways, the multicolor up-conversion fluorescence can be finely tuned. This color tuning by the femtosecond pulse shaping technique is realized in single material by single-color laser field, which is highly desirable for further applications of the lanthanide-doped nanocrystals. This femtosecond pulse shaping technique opens an opportunity to tune the color output in the lanthanide-doped nanocrystals, which may bring a new revolution in the control of luminescence properties of nanomaterials. PMID:26290391

Structural and light up-conversion luminescence properties of Er3+-Yb3+-W6+ substituted Bi4Ti3O12

NASA Astrophysics Data System (ADS)

Bokolia, Renuka; Rai, Vineet K.; Chauhan, Lalita; Sreenivas, K.

2016-05-01

The structural and light up-conversion (UC) luminescence properties of W6+ substituted Bi3.79Er0.03Yb0.18Ti3-xWxO12 (0 ≤ x ≤ 0.10) ceramics prepared by solid state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of single phase material with orthorhombic structure. A decrease in the lattice parameters and unit cell volume is observed with increasing W content. Strong UC luminescence at 527, 548 and 662 nm is seen under an excitation of 980 nm for an optimum W content (x = 0.06) and is attributed to the transitions 2H11/2 →4I15/2, 4S3/2 →4I15/2 and 4F9/2 →4I15/2 respectively. The improved UC luminescence is ascribed to the reduced defects such as oxygen vacancies and change in the crystal field around Er3+ ions due to B-site (Ti4+) substitution with W6+ ions. Enhanced UC emission is observed for an optimum content of w6+ in the prepared composition Bi3.79Er0.03Yb0.18Ti3-xWxO12 for x = 0.06.

Color-tunable up-conversion emission in Y2O3:Yb3+, Er3+ nanoparticles prepared by polymer complex solution method

PubMed Central

2013-01-01

Abstract Powders of Y2O3 co-doped with Yb3+ and Er3+ composed of well-crystallized nanoparticles (30 to 50 nm in diameter) with no adsorbed ligand species on their surface are prepared by polymer complex solution method. These powders exhibit up-conversion emission upon 978-nm excitation with a color that can be tuned from green to red by changing the Yb3+/Er3+ concentration ratio. The mechanism underlying up-conversion color changes is presented along with material structural and optical properties. PACS 42.70.-a, 78.55.Hx, 78.60.-b PMID:23522083

Detection of telomerase on upconversion nanoparticle modified cellulose paper.

PubMed

Wang, Faming; Li, Wen; Wang, Jiasi; Ren, Jinsong; Qu, Xiaogang

2015-07-25

Herein we report a convenient and sensitive method for the detection of telomerase activity based on upconversion nanoparticle (UCNP) modified cellulose paper. Compared with many solution-phase systems, this paper chip is more stable and easily stores the test results. What's more, the low background fluorescence of the UCNPs increases the sensitivity of this method, and the low telomerase levels in different cell lines can clearly be discriminated by the naked eye.

Solar-Pumping Upconversion of Interfacial Coordination Nanoparticles.

PubMed

Ishii, Ayumi; Hasegawa, Miki

2017-01-30

An interfacial coordination nanoparticle successfully exhibited an upconversion blue emission excited by very low-power light irradiation, such as sunlight. The interfacial complex was composed of Yb ions and indigo dye, which formed a nano-ordered thin shell layer on a Tm 2 O 3 nanoparticle. At the surface of the Tm 2 O 3 particle, the indigo dye can be excited by non-laser excitation at 640 nm, following the intramolecular energy transfer from the indigo dye to the Yb ions. Additionally, the excitation energy of the Yb ion was upconverted to the blue emission of the Tm ion at 475 nm. This upconversion blue emission was achieved by excitation with a CW Xe lamp at an excitation power of 0.14 mW/cm 2 , which is significantly lower than the solar irradiation power of 1.4 mW/cm 2 at 640 ± 5 nm.

Synthesis of Er(III)/Yb(III)-doped BiF3 upconversion nanoparticles for use in optical thermometry.

PubMed

Du, Peng; Yu, Jae Su

2018-03-23

The authors describe an ethylene glycol assisted precipitation method for synthesis of Er(III)/Yb(III)-doped BiF 3 nanoparticles (NPs) at room temperature. Under 980-nm light irradiation, the NPs emit upconversion (UC) emission of Er(III) ions as a result of a two-photon absorption process. The temperature-dependent green emissions (peaking at 525 and 545 nm) are used to establish an unambiguous relationship between the ratio of fluorescence intensities and temperature. The NPs have a maximum sensitivity of 6.5 × 10 -3  K -1 at 619 K and can be applied over the 291-691 K temperature range. The results indicate that these NPs are a promising candidate for optical thermometry. Graphical abstract Schematic of the room-temperature preparation of Er(III)/Yb(III)-doped BiF 3 nanoparticles with strongly temperature-dependent upconversion emission.

Laser-diode-excited blue upconversion in Tm3+/Yb3+ -codoped TeO2-Ga2O3-R2O (R=Li, Na, K) glasses.

PubMed

Zhao, Chun; Zhang, Qinyuan; Yang, Gangfeng; Jiang, Zhonghong

2008-01-01

This paper reports on intense blue upconversion in Tm(3+)/Yb(3+) codoped TeO(2)-Ga(2)O(3)-R(2)O(R=Li, Na, K) glasses upon excitation with commercial available laser diode (LD). Effects of alkali ions on the Raman spectra, thermal stability and spectroscopic properties of the tellurite-gallium glasses have also been investigated. Energy transfer and the involved upconversion mechanisms have been discussed. Intense blue upconversion emission centered at 476 nm along with a weak red emission at 650 nm has been observed upon excitation of 977 nm LD, assigned to the transitions of 1G4-->3H6, and 1G4-->3H4 and/or 3F(2,3)-->3H6 of Tm(3+), respectively. The blue upconversion intensity has a cubelike dependence on incident pump laser power, indicating a three-photon process. However, a quadratic dependence of the 476 nm upconversion intensity on the incident pump laser power has been observed when samples under excitation of 808 nm LD due to a two-photon absorption process. Enhanced upconversion luminescence have been observed with replacing K(+) for Na(+) and Li(+).

Plasmon-Induced Selective Enhancement of Green Emission in Lanthanide-Doped Nanoparticles.

PubMed

Zhang, Weina; Li, Juan; Lei, Hongxiang; Li, Baojun

2017-12-13

By introducing an 18 nm thick Au nanofilm, selective enhancement of green emission from lanthanide-doped (β-NaYF 4 :Yb 3+ /Er 3+ ) upconversion nanoparticles (UCNPs) is demonstrated. The Au nanofilm is deposited on a microfiber surface by the sputtering method and then covered with the UCNPs. The plasma on the surface of the Au nanofilm can be excited by launching a 980 nm wavelength laser beam into the microfiber, resulting in an enhancement of the local electric field and a strong thermal effect. A 36-fold luminescence intensity enhancement of the UCNPs at 523 nm is observed, with no obvious reduction in the photostability of the UCNPs. Further, the intensity ratios of the emissions at 523-545 nm and at 523-655 nm are enhanced with increasing pump power, which is attributed to the increasing plasmon-induced thermal effect. Therefore, the fabricated device is further demonstrated to exhibit an excellent ability in temperature sensing. By controlling the pump power and the UCNP concentration, a wide temperature range (325-811 K) and a high temperature resolution (0.035-0.046 K) are achieved in the fabricated device.

Er{sup 3+}/Yb{sup 3+}co-doped bismuth molybdate nanosheets upconversion photocatalyst with enhanced photocatalytic activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adhikari, Rajesh; Gyawali, Gobinda; Cho, Sung Hun

2014-01-15

In this paper, we report the microwave hydrothermal synthesis of Er{sup 3+}/Yb{sup 3+} co-doped Bi{sub 2}MoO{sub 6} upconversion photocatalyst. Crystal structure, morphology, elemental composition, optical properties and BET surface area were analyzed in detail. Infrared to visible upconversion luminescence at 532 nm and 546 nm of the co-doped samples was investigated under excitation at 980 nm. The results revealed that the co-doping of Er{sup 3+}/Yb{sup 3+} into Bi{sub 2}MoO{sub 6} exhibited enhanced photocatalytic activity for the decomposition of rhodamine B under simulated solar light irradiation. Enhanced photocatalytic activity can be attributed to the energy transfer between Er{sup 3+}/Yb{sup 3+} andmore » Bi{sub 2}MoO{sub 6} via infrared to visible upconversion from Er{sup 3+}/Yb{sup 3+} ion and higher surface area of the Bi{sub 2}MoO{sub 6} nanosheets. Therefore, this synthetic approach may exhibit a better alternative to fabricate upconversion photocatalyst for integral solar light absorption. - Graphical abstract: Schematic illustration of the upconversion photocatalysis. Display Omitted - Highlights: • Er{sup 3+}/Yb{sup 3+} co-doped Bi{sub 2}MoO{sub 6} upconversion photocatalyst is successfully synthesized. • We obtained the nanosheets having high surface area. • Upconversion of IR to visible light was confirmed. • Upconversion phenomena can be utilized for effective photocatalysis.« less

Luminescence properties of Tm3+ ions single-doped YF3 materials in an unconventional excitation region.

PubMed

Chen, Yuan; Liu, Qing; Lin, Han; Yan, Xiaohong

2018-05-01

According to the spectral distribution of solar radiation at the earth's surface, under the excitation region of 1150 to 1350 nm, the up-conversion luminescence of Tm 3+ ions was investigated. The emission bands were matched well with the spectral response region of silicon solar cells, achieved by Tm 3+ ions single-doped yttrium fluoride (YF 3 ) phosphor, which was different from the conventional Tm 3+ /Yb 3+ ion couple co-doped materials. Additionally, the similar emission bands of Tm 3+ ions were achieved under excitation in the ultraviolet region. It is expected that via up-conversion and down-conversion routes, Tm 3+ -sensitized materials could convert photons to the desired wavelengths in order to reduce the energy loss of silicon solar cells, thereby enhancing the photovoltaic efficiency. Copyright © 2018 John Wiley & Sons, Ltd.

Optical thermometry using fluorescence intensities multi-ratios in NaGdTiO4:Yb3+/Tm3+ phosphors

NASA Astrophysics Data System (ADS)

Zhou, Aihua; Song, Feng; Song, Feifei; Feng, Ming; Adnan, Khan; Ju, Dandan; Wang, Xueqing

2018-04-01

The NaGdTiO4:Yb3+/Tm3+ phosphor has been effectively synthesized by the traditional solid-state reaction method and its down-conversion and up-conversion luminescence properties were systematically studied. The results indicate that the electric dipole-dipole interaction is the main mechanism for the luminescence quenching. The fact that the ratios of the up-conversion intensities, i.e., I795nm/I798nm, I807nm/I798nm, and I812nm/I798nm, increase linearly with temperature (100 K-300 K) provides us a simple and accurate temperature measurement method. Multi-ratios can be more accurate than using only one ratio, allowing for self-referenced temperature determination. It's promising for NaGdTiO4: Yb3+/Tm3+ to be used for optical temperature sensors.

Monitoring Delamination of Thermal Barrier Coatings During Interrupted High-Heat-Flux Laser Testing using Luminescence Imaging

NASA Technical Reports Server (NTRS)

Eldridge, Jeffrey I.; Zhu, Dongming; Wolfe, Douglas E.

2011-01-01

This presentation showed progress made in extending luminescence-base delamination monitoring to TBCs exposed to high heat fluxes, which is an environment that much better simulates actual turbine engine conditions. This was done by performing upconversion luminescence imaging during interruptions in laser testing, where a high-power CO2 laser was employed to create the desired heat flux. Upconverison luminescence refers to luminescence where the emission is at a higher energy (shorter wavelength) than the excitation. Since there will be negligible background emission at higher energies than the excitation, this methods produces superb contrast. Delamination contrast is produced because both the excitation and emission wavelengths are reflected at delamination cracks so that substantially higher luminescence intensity is observed in regions containing delamination cracks. Erbium was selected as the dopant for luminescence specifically because it exhibits upconversion luminescence. The high power CO2 10.6 micron wavelength laser facility at NASA GRC was used to produce the heat flux in combination with forced air backside cooling. Testing was performed at a lower (95 W/sq cm) and higher (125 W/sq cm) heat flux as well as furnace cycling at 1163C for comparison. The lower heat flux showed the same general behavior as furnace cycling, a gradual, "spotty" increase in luminescence associated with debond progression; however, a significant difference was a pronounced incubation period followed by acceleration delamination progression. These results indicate that extrapolating behavior from furnace cycling measurements will grossly overestimate remaining life under high heat flux conditions. The higher heat flux results were not only accelerated, but much different in character. Extreme bond coat rumpling occurred, and delamination propagation extended over much larger areas before precipitating macroscopic TBC failure. This indicates that under the higher heat flux (and surface & interface temperatures), the TBC was more tolerant of damage. The main conclusions were that high heat flux conditions can not only accelerate TBC debond progression but can also grossly alter the pathway of delamination.

Synergistically Enhanced Performance of Ultrathin Nanostructured Silicon Solar Cells Embedded in Plasmonically Assisted, Multispectral Luminescent Waveguides.

PubMed

Lee, Sung-Min; Dhar, Purnim; Chen, Huandong; Montenegro, Angelo; Liaw, Lauren; Kang, Dongseok; Gai, Boju; Benderskii, Alexander V; Yoon, Jongseung

2017-04-25

Ultrathin silicon solar cells fabricated by anisotropic wet chemical etching of single-crystalline wafer materials represent an attractive materials platform that could provide many advantages for realizing high-performance, low-cost photovoltaics. However, their intrinsically limited photovoltaic performance arising from insufficient absorption of low-energy photons demands careful design of light management to maximize the efficiency and preserve the cost-effectiveness of solar cells. Herein we present an integrated flexible solar module of ultrathin, nanostructured silicon solar cells capable of simultaneously exploiting spectral upconversion and downshifting in conjunction with multispectral luminescent waveguides and a nanostructured plasmonic reflector to compensate for their weak optical absorption and enhance their performance. The 8 μm-thick silicon solar cells incorporating a hexagonally periodic nanostructured surface relief are surface-embedded in layered multispectral luminescent media containing organic dyes and NaYF 4 :Yb 3+ ,Er 3+ nanocrystals as downshifting and upconverting luminophores, respectively, via printing-enabled deterministic materials assembly. The ultrathin nanostructured silicon microcells in the composite luminescent waveguide exhibit strongly augmented photocurrent (∼40.1 mA/cm 2 ) and energy conversion efficiency (∼12.8%) than devices with only a single type of luminescent species, owing to the synergistic contributions from optical downshifting, plasmonically enhanced upconversion, and waveguided photon flux for optical concentration, where the short-circuit current density increased by ∼13.6 mA/cm 2 compared with microcells in a nonluminescent medium on a plain silver reflector under a confined illumination.

Synergistically Enhanced Performance of Ultrathin Nanostructured Silicon Solar Cells Embedded in Plasmonically Assisted, Multispectral Luminescent Waveguides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sung-Min; Dhar, Purnim; Chen, Huandong

Ultrathin silicon solar cells fabricated by anisotropic wet chemical etching of single-crystalline wafer materials represent an attractive materials platform that could provide many advantages for realizing high-performance, low-cost photovoltaics. However, their intrinsically limited photovoltaic performance arising from insufficient absorption of low-energy photons demands careful design of light management to maximize the efficiency and preserve the cost-effectiveness of solar cells. Herein we present an integrated flexible solar module of ultrathin, nanostructured silicon solar cells capable of simultaneously exploiting spectral upconversion and downshifting in conjunction with multispectral luminescent waveguides and a nanostructured plasmonic reflector to compensate for their weak optical absorption andmore » enhance their performance. The 8 μm-thick silicon solar cells incorporating a hexagonally periodic nanostructured surface relief are surface-embedded in layered multispectral luminescent media containing organic dyes and NaYF4:Yb3+,Er3+ nanocrystals as downshifting and upconverting luminophores, respectively, via printing-enabled deterministic materials assembly. The ultrathin nanostructured silicon microcells in the composite luminescent waveguide exhibit strongly augmented photocurrent (~40.1 mA/cm2) and energy conversion efficiency (~12.8%) than devices with only a single type of luminescent species, owing to the synergistic contributions from optical downshifting, plasmonically enhanced upconversion, and waveguided photon flux for optical concentration, where the short-circuit current density increased by ~13.6 mA/cm2 compared with microcells in a nonluminescent medium on a plain silver reflector under a confined illumination.« less

Scalable Direct Writing of Lanthanide-Doped KMnF3 Perovskite Nanowires into Aligned Arrays with Polarized Up-Conversion Emission.

PubMed

Shi, Shuo; Sun, Ling-Dong; Xue, Ying-Xian; Dong, Hao; Wu, Ke; Guo, Shi-Chen; Wu, Bo-Tao; Yan, Chun-Hua

2018-05-09

The use of one-dimensional nano- and microstructured semiconductor and lanthanide materials is attractive for polarized-light-emission studies. Up-conversion emission from single-nanorod or anisotropic nanoparticles with a degree of polarization has also been discussed. However, microscale arrays of nanoparticles, especially well-aligned one-dimensional nanostructures as well as their up-conversion polarization characterization, have not been investigated yet. Herein, we present a novel and facile paradigm for preparing highly aligned arrays of lanthanide-doped KMnF 3 (KMnF 3 :Ln) perovskite nanowires, which are good candidates for polarized up-conversion emission studies. These perovskite nanowires, with a width of 10 nm and length of a few micrometers, are formed through the oriented attachment of KMnF 3 :Ln nanocubes along the [001] direction. By the employment of KMnF 3 :Ln nanowire gel as nanoink, a direct-writing method is developed to obtain diverse types of aligned patterns from the nanoscale to the wafer scale. Up-conversion emissions from the highly aligned nanowire arrays are polarized along the array direction with a polarization degree up to 60%. Taking advantage of microscopic nanowire arrays, these polarized up-conversion emissions should offer potential applications in light or information transportation.

Dental optical tomography with upconversion nanoparticles-a feasibility study.

PubMed

Long, Feixiao; Intes, Xavier

2017-06-01

Upconversion nanoparticles (UCNPs) have the unique ability to emit multiple colors upon excitation by near-infrared (NIR) light. Herein, we investigate the potential use of UCNPs as contrast agents for dental optical tomography, with a focus on monitoring the status of fillings after dental restoration. The potential of performing tomographic imaging using UCNP emission of visible or NIR light is established. This in silico and ex vivo study paves the way toward employing UCNPs as theranostic agents for dental applications.

Enhanced electrical properties, color-tunable up-conversion luminescence, and temperature sensing behaviour in Er-doped Bi3Ti1.5W0.5O9 multifunctional ferroelectric ceramics

NASA Astrophysics Data System (ADS)

Zhang, Ying; Li, Jun; Chai, Xiaona; Wang, Xusheng; Li, Yongxiang; Yao, Xi

2017-03-01

Er-doped Bi3Ti1.5W0.5O9 (BTW-x) ferroelectric ceramics were prepared by a conventional solid-state reaction synthesis method, and their structure, electrical properties, up-conversion (UC) luminescence, and temperature sensing behaviour were investigated. A high piezoelectric coefficient d33 (9.6 pC/N), a large remnant polarization Pr (12.75 μC/cm2), a high Curie temperature Tc (730.2 °C), and the optimal luminescent intensity are obtained for the samples at x = 0.05. By changing the Er doped concentration, the BTW-x ceramics are capable of generating various UC spectra and the color could be tunable from green to yellow. According to the fluorescence intensity ratio of green emissions at 532.6 nm and 549.2 nm in the temperature range from 83 K to 423 K, optical temperature sensing properties are investigated and the maximum sensing sensitivity is found to be 0.00314 K-1 at 423 K. The results conclude that BTW-x would be a candidate in high temperature sensor, fluorescence thermometry, and opto-electronic integration applications.

Up-conversion in an Er-containing nanocomposite and microlasers based on it

NASA Astrophysics Data System (ADS)

Sobeshchuk, N. O.; Denisyuk, I. Yu.

2017-06-01

The results of an investigation of three-dimensional polymer microcavities doped with inorganic luminescent particles are presented. Microlasers in the form of rectangular parallelepipeds were fabricated based on the SU8 2025 photoresist by means of compact UV lithography. Luminescent particles containing erbium oxide were obtained by low-temperature synthesis of the corresponding chlorides in a nonaqueous medium. The obtained spectra confirm the presence of a narrowband laser radiation exhibiting a Stokes shift.

Measuring upconversion nanoparticles photoluminescence lifetime with FastFLIM and phasor plots

NASA Astrophysics Data System (ADS)

Sun, Yuansheng; Lee, Hsien-Ming; Qiu, Hailin; Liao, Shih-Chu Jeff; Coskun, Ulas; Barbieri, Beniamino

2018-02-01

Photon upconversion is a nonlinear process in which the sequential of absorption of two or more photons leads to the anti-stoke emission. Different than the conventional multiphoton excitation process, upconversion can be efficiently performed at low excitation densities. Recent developments in lanthanide-doped upconversion nanoparticles (UCNPs) have led to a diversity of applications, including detecting and sensing of biomolecules, imaging of live cells, tissues and animals, cancer diagnostic and therapy, etc. Measuring the upconversion lifetime provides a new dimension of its imaging and opens a new window for its applications. Due to the long metastable intermediate excited state, UCNP typically has a long excited state lifetime ranging from sub-microseconds to milliseconds. Here, we present a novel development using the FastFLIM technique to measure UCNP lifetime by laser scanning confocal microscopy. FastFLIM is capable of measuring lifetime from 100 ps to 100 ms and features the high data collection efficiency (up to 140-million counts per second). Other than the traditional nonlinear least-square fitting analysis, the raw data acquired by FastFLIM can be directly processed by the model-free phasor plots approach for instant and unbiased lifetime results, providing the ideal routine for the UCNP photoluminescence lifetime microscopy imaging.

Frequency upconversion in Er3+ doped tungsten tellurite glass containing Ag nanoparticles

NASA Astrophysics Data System (ADS)

Mahajan, S. K.; Parashar, J.

2018-05-01

The frequency upconversion emission in Er3+ doped TeO2-WO3-Li2O containing Ag nanoparticle (TWLEOAG) glasses at 980nm excitation is reported. The absorption spectra reveal not only the peaks due to Er3+ ions, but also the surface plasmon resonance band of silver NPs located around 525nm and 650 nm. The spherical AgNPs with average size ˜38 nm in the glassy matrix is evidenced from the TEM measurement. Under 980nm laser excitation upconversion emission spectra show two major emission at 550nm and 638nm originating from 4S3/2 and 4F9/2 energy levels of the Er3+ ions, respectively was observed. Upconversion emission enhancement factor 7 fold has been measured for sample heat treated during 40h. However for 18h heat treated TWLEOAG sample under 980 nm flash lamp excitation produced Intense green compare to red emission. Since the 980nm frequency is far from the AgNPs surface plasmon resonance frequency, visible emission ehancement is attributed to local field increase in proximity of the Ag NPs and not energy tranfer from NPs to emitters. Possible energy transfer upconversion mechanism has been also discussed.

Infrared-to-visible conversion luminescence of Er 3+ ions in lead borate transparent glass-ceramics

NASA Astrophysics Data System (ADS)

Pisarski, Wojciech A.; Pisarska, Joanna; Lisiecki, Radosław; Grobelny, Łukasz; Dominiak-Dzik, Grażyna; Ryba-Romanowski, Witold

2009-10-01

Transparent glass-ceramics were successfully prepared during controlled heat treatment of lead borate glasses. The PbF 2 particles were dispersed into a borate glass matrix which was evidenced by X-ray diffraction analysis. The phase identification revealed that crystalline peaks can be related to the orthorhombic PbF 2 phase. Green up-conversion luminescence due to the 4S 3/2- 4I 15/2 transition of Er 3+ ions was registered. In comparison to the precursor glass the luminescence intensity was considerably higher, whereas the luminescence linewidth slightly decreased in the studied oxyfluoride transparent glass-ceramics. It indicated that a part of the trivalent erbium was incorporated into the PbF 2 crystalline phase.

Silica nanoparticles with a substrate switchable luminescence

NASA Astrophysics Data System (ADS)

Bochkova, O. D.; Mustafina, A. R.; Fedorenko, S. V.; Konovalov, A. I.

2011-04-01

Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR luminescence (Ru-Yb doped) were obtained by reverse w/o microemulsion procedure. Plenty of luminescent complexes (from 4900 to 10000) encapsulated into each nanoparticle ensures the intensive luminescence of nanoparticles and their applicability as biomarkers. The silica surface decoration by definite anchor groups is the required step for the gaining to these nanoparticles marking and sensing functions. Thus covalent and non-covalent surface modification of these nanoparticles was developed to provide the binding with biotargets and sensing of anions. The dicationic surfactant coating of negatively charged Tb(III)-TCAS doped silica nanoparticles was chosen as the basis for the anion responsible system. The reversible insertion of the quenching anions (namely phenol red) into the surfactant based layer at the surface of luminescent nanoparticles switches off the Tb-centered luminescence. In turn the reversible reestablishment of the luminescence results from the competitive insertion of the non-quenching anions into the surfactant layer at the silica/water interface. The hydrophobic anions exemplified by dodecylsulfates versus hydrophilic ones (hydrophosphates) are preferable in the competition with phenol red anions.

Anti-Stokes Luminescence in High Quality Quantum Wells

NASA Astrophysics Data System (ADS)

Vinattieri, A.; Bogani, F.; Miotto, A.; Ceccherini, S.

1997-11-01

We present a detailed investigation of the anti-Stokes (AS) luminescence which originates from exciton recombination when below gap excitation is used, in a set of high quality quantum well structures. We observe strong excitonic resonances in the AS signal as measured from photoluminescence and photoluminescence excitation spectra. We demonstrate that neither the electromagnetic coupling between the wells nor the morphological disorder can explain this up-conversion effect. Time-resolved luminescence data after ps excitation and fs correlation spectroscopy results provide clear evidence of the occurrence of a two-step absorption which is assisted by the exciton population resonantly excited by the first photon.

Simultaneous realization of Hg2+ sensing, magnetic resonance imaging and upconversion luminescence in vitro and in vivo bioimaging based on hollow mesoporous silica coated UCNPs and ruthenium complex

NASA Astrophysics Data System (ADS)

Ge, Xiaoqian; Sun, Lining; Ma, Binbin; Jin, Di; Dong, Liang; Shi, Liyi; Li, Nan; Chen, Haige; Huang, Wei

2015-08-01

We have constructed a multifunctional nanoprobe with sensing and imaging properties by using hollow mesoporous silica coated upconversion nanoparticles (UCNPs) and Hg2+ responsive ruthenium (Ru) complex. The Ru complex was loaded into the hollow mesoporous silica and the UCNPs acted as an energy donor, transferring luminescence energy to the Ru complex. Furthermore, polyethylenimine (PEI) was assembled on the surface of mesoporous silica to achieve better hydrophilic and bio-compatibility. Upon addition of Hg2+, a blue shift of the absorption peak of the Ru complex is observed and the energy transfer process between the UCNPs and the Ru complex was blocked, resulting in an increase of the green emission intensity of the UCNPs. The un-changed 801 nm emission of the nanoprobe was used as an internal standard reference and the detection limit of Hg2+ was determined to be 0.16 μM for this nanoprobe in aqueous solution. In addition, based on the low cytotoxicity as studied by CCK-8 assay, the nanoprobe was successfully applied for cell imaging and small animal imaging. Furthermore, when doped with Gd3+ ions, the nanoprobe was successfully applied to in vivo magnetic resonance imaging (MRI) of Kunming mice, which demonstrates its potential as a MRI positive-contrast agent. Therefore, the method and results may provide more exciting opportunities to afford nanoprobes with multimodal bioimaging and multifunctional applications.We have constructed a multifunctional nanoprobe with sensing and imaging properties by using hollow mesoporous silica coated upconversion nanoparticles (UCNPs) and Hg2+ responsive ruthenium (Ru) complex. The Ru complex was loaded into the hollow mesoporous silica and the UCNPs acted as an energy donor, transferring luminescence energy to the Ru complex. Furthermore, polyethylenimine (PEI) was assembled on the surface of mesoporous silica to achieve better hydrophilic and bio-compatibility. Upon addition of Hg2+, a blue shift of the absorption peak of the Ru complex is observed and the energy transfer process between the UCNPs and the Ru complex was blocked, resulting in an increase of the green emission intensity of the UCNPs. The un-changed 801 nm emission of the nanoprobe was used as an internal standard reference and the detection limit of Hg2+ was determined to be 0.16 μM for this nanoprobe in aqueous solution. In addition, based on the low cytotoxicity as studied by CCK-8 assay, the nanoprobe was successfully applied for cell imaging and small animal imaging. Furthermore, when doped with Gd3+ ions, the nanoprobe was successfully applied to in vivo magnetic resonance imaging (MRI) of Kunming mice, which demonstrates its potential as a MRI positive-contrast agent. Therefore, the method and results may provide more exciting opportunities to afford nanoprobes with multimodal bioimaging and multifunctional applications. Electronic supplementary information (ESI) available: DLS of Ru-UCNPs@HmSiO2-PEI in water. The zeta potential. The XRD patterns. EDX spectrum of Ru-UCNPs@HmSiO2-PEI. FT-IR spectra. N2 adsorption-desorption isotherm and pore size distribution. The investigation of the stability of Ru-UCNPs@HmSiO2-PEI. TG curves. UV/Vis absorption spectra of Ru complex at different concentrations. The sensitivity test of Ru-UCNPs@HmSiO2-PEI towards Hg2+. Cell viabilities of HeLa cells incubated with Ru-UCNPs@HmSiO2-PEI. See DOI: 10.1039/c5nr04006j

NIR to NIR upconversion in KYb2F7: RE3+ (RE = Tm, Er) nanoparticles for biological imaging

NASA Astrophysics Data System (ADS)

Pedraza, F.; Yust, B.; Tsin, A.; Sardar, D.

2014-03-01

Until recently, many contrast agents widely used in biological imaging have absorbed and emitted in the visible region, limiting their usefulness for deeper tissue imaging. In order to push the boundaries of deep tissue imaging with non-ionizing radiation, contrast agents in the near infrared (NIR) regime, which is not strongly absorbed or scattered by most tissues, are being sought after. Upconverting nanoparticles (UCNPs) are attractive candidates since their upconversion emission is tunable with a very narrow bandwidth and they do not photobleach or blink. The upconversion produced by the nanoparticles can be tailored for NIR to NIR by carefully choosing the lanthanide dopants and dopant ratios such as KYb2F7: RE3+ (RE = Tm, Er). Spectroscopic characterization was done by analyzing absorption, fluorescence, and quantum yield data. In order to study the toxicity of the nanoparticles Monkey Retinal Endothelial Cells (MREC) were cultivated in 24 well plates and then treated with nanoparticles at different concentrations in triplicate to obtain the optimal concentration for in vivo experiments. It will be shown that these UCNPs do not elicit a strong toxic response such as quantum dots and some noble metal nanoparticles. 3-D optical slices of nanoparticle treated fibroblast cells were imaged using a confocal microscope where the nucleus and cytoplasm were stained with DAPI and Alexa Fluor respectively. These results presented support the initial assumption, which suggests that KYb2F7: RE3+ would be excellent candidates for NIR contrast agents.

Tailoring dye-sensitized upconversion nanoparticle excitation bands towards excitation wavelength selective imaging

DOE PAGES

Wu, Xiang; Lee, Hyungseok; Bilsel, Osman; ...

2015-01-01

One of the key roadblocks in UCNP development is its extremely limited choices of excitation wavelengths. We report a generic design to program UCNPs to possess highly tunable dye characteristic excitation bands. Using such distinctive properties, we were able to develop a new excitation wavelength selective security imaging. Finally, this work unleashed the greater freedom of the excitation wavelengths of the upconversion nanoparticles and we believe it is a game-changer in the field and this method will enable numerous applications that are currently limited by existing UCNPs.

Facile EG/ionic liquid interfacial synthesis of uniform RE(3+) doped NaYF(4) nanocubes.

PubMed

Zhang, Chao; Chen, Ji

2010-01-28

Uniform multicolor upconversion luminescent RE(3+) doped NaYF(4) nanocubes are fabricated through a facile ethylene glycol (EG)/ionic liquid interfacial synthesis route at 80 degrees C, with the ionic liquids acting as both reagents and templates.

Synthesis of novel branched β-NaLuF4: Yb/Er upconversion luminescence material and investigation of its optical properties

NASA Astrophysics Data System (ADS)

Ding, Yanli; Yang, Tonghui; Yin, Naiqiang; Shu, Fangjie; Zhao, Ying; Zhang, Xiaodan

2018-05-01

Branched β-NaLuF4: Yb/Er was synthesized using a simple hydrothermal method by controlling the NaF/Ln molar ratio. In contrast to the β-NaYF4: Yb/Er hexagonal disks, the branched β-NaLuF4: Yb/Er has stronger emission intensity. The integrated intensities of green and red emission bands were as 6.2 and 3.3 times as that of NaYF4, respectively. The branched β-NaLuF4: Yb/Er has the smaller unit cell volume, the higher absorption intensity around 980 nm and the lower crystal field symmetry than NaYF4, which made a significant contribution to the stronger upconversion (UC) fluorescence emissions. The results indicate that the branched β-NaLuF4: Yb/Er is an excellent UC luminescence material. The current research has a great potential in improving near-infrared conversion efficiency of solar cells.

M2+ Doping Induced Simultaneous Phase/Size Control and Remarkable Enhanced Upconversion Luminescence of NaLnF4 Probes for Optical-Guided Tiny Tumor Diagnosis.

PubMed

Li, Youbin; Li, Xiaolong; Xue, Zhenluan; Jiang, Mingyang; Zeng, Songjun; Hao, Jianhua

2017-05-01

Doping has played a vital role in constructing desirable hybrid materials with tunable functions and properties via incorporating atoms into host matrix. Herein, a simple strategy for simultaneously modifying the phase, size, and upconversion luminescence (UCL) properties of the NaLnF 4 (Ln = Y, Yb) nanocrystals by high-temperature coprecipitation through nonequivalent M 2+ doping (M = Mg 2+ , Co 2+ ) has been demonstrated. The phase transformation from cubic to hexagonal is readily achieved by doping M 2+ . Compared with Mg-free sample, a remarkable enhancement of overall UCL (≈27.5 times) is obtained by doping Mg 2+ . Interestingly, owing to the efficient UCL, red UCL-guided tiny tumor (down to 3 mm) diagnosis is demonstrated for the first time. The results open up a new way of designing high efficient UCL probe with combination of hexagonal phase and small size for tiny tumor detection. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luminescence in Conjugated Molecular Materials under Sub-bandgap Excitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

So, Franky

2014-05-08

Light emission in semiconductors occurs when they are under optical and electrical excitation with energy larger than the bandgap energy. In some low-dimensional semiconductor heterostructure systems, this thermodynamic limit can be violated due to radiative Auger recombination (AR), a process in which the sub-bandgap energy released from a recombined electron-hole pair is transferred to a third particle leading to radiative band-to-band recombination.1 Thus far, photoluminescence up-conversion phenomenon has been observed in some low dimensional semiconductor systems, and the effect is very weak and it can only be observed at low temperatures. Recently, we discovered that efficient electroluminescence in poly[2-methoxy-5-(2’-ethylhexyloxy)-1, phenylenevinylene]more » (MEH-PPV) polymer light-emitting devices (PLEDs) at drive voltages below its bandgap voltage could be observed when a ZnO nanoparticles (NPs) electron injection layer was inserted between the polymer and the aluminum electrode. Specifically, emitted photons with energy of 2.13 eV can be detected at operating voltages as low as 1.2 V at room temperature. Based on these data, we propose that the sub-bandgap turn-on in the MEH-PPV device is due to an Auger-assisted energy up-conversion process. The significance of this discovery is three-fold. First, radiative recombination occurs at operating voltages below the thermodynamic bandgap voltage. This process can significantly reduce the device operating voltage. For example, the current density of the device with the ZnO NC layer is almost two orders of magnitude higher than that of the device without the NC layer. Second, a reactive metal is no longer needed for the cathode. Third, this electroluminescence up-conversion process can be applied to inorganic semiconductors systems as well and their operation voltages of inorganic LEDs can be reduced to about half of the bandgap energy. Based on our initial data, we propose that the sub-bandgap turn-on in MEH-PPV devices is due to Auger-assisted energy up-conversion process. Specifically, we propose that the up-conversion process is due to charge accumulation at the polymer/NPs interface. This model requires that holes should be the dominant carriers in the polymer and the polymer/ZnO NCs heterojunction should be a type II alignment. In order to determine the mechanism of the up-conversion process, we will characterize devices fabricated using polymers with different carrier transporting properties to determine whether hole accumulation at the polymer/nanocrystals is required. Likewise, we will also use NPs with different electronic structures to fabricate devices to determine how electron accumulation affects the up-conversion process. Finally, we will measure quantitatively the interface charge accumulation by electroabsorption and correlate the results with the up-conversion photoluminescence efficiency measurements under an applied electric field.« less

A paper-based resonance energy transfer nucleic acid hybridization assay using upconversion nanoparticles as donors and quantum dots as acceptors.

PubMed

Doughan, Samer; Uddayasankar, Uvaraj; Krull, Ulrich J

2015-06-09

Monodisperse aqueous upconverting nanoparticles (UCNPs) were covalently immobilized on aldehyde modified cellulose paper via reduction amination to develop a luminescence resonance energy transfer (LRET)-based nucleic acid hybridization assay. This first account of covalent immobilization of UCNPs on paper for a bioassay reports an optically responsive method that is sensitive, reproducible and robust. The immobilized UCNPs were decorated with oligonucleotide probes to capture HPRT1 housekeeping gene fragments, which in turn brought reporter conjugated quantum dots (QDs) in close proximity to the UCNPs for LRET. This sandwich assay could detect unlabeled oligonucleotide target, and had a limit of detection of 13 fmol and a dynamic range spanning nearly 3 orders of magnitude. The use of QDs, which are excellent LRET acceptors, demonstrated improved sensitivity, limit of detection, dynamic range and selectivity compared to similar assays that have used molecular fluorophores as acceptors. The selectivity of the assay was attributed to the decoration of the QDs with polyethylene glycol to eliminate non-specific adsorption. The kinetics of hybridization were determined to be diffusion limited and full signal development occurred within 3 min. Copyright © 2015 Elsevier B.V. All rights reserved.

Upconverting fluorescent nanoparticles for biodetection and photoactivation

NASA Astrophysics Data System (ADS)

Huang, Kai; Li, WenKai; Jayakumar, Muthu Kumara Gnanasammandhan; Zhang, Yong

2013-03-01

Fluorophores including fluorescent dyes/proteins and quantum dots (QDs) are used for fluorescence-based imaging and detection. These are based on `downconversion fluorescence' and have several drawbacks: photobleaching, autofluorescence, short tissue penetration depth and tissue photo-damage. Upconversion fluorescent nanoparticles (UCNs) emit detectable photons of higher energy in the short wavelength range upon irradiation with near-infrared (NIR) light based on a process termed `upconversion'. UCNs show absolute photostability, negligible autofluorescence, high penetration depth and minimum photodamage to biological tissues. Lanthanide doped nanocrystals with nearinfrared NIR-to-NIR and/or NIR-to-VIS and/or NIR-to-UV upconversion fluorescence emission have been synthesized. The nanocrystals with small size and tunable multi-color emission have been developed. The emission can be tuned by doping different upconverting lanthanide ions into the nanocrystals. The nanocrystals with core-shell structure have also been prepared to tune the emission color. The surfaces of these nanocrystals have been modified to render them water dispersible and biocompatible. They can be used for ultrasensitive interference-free biodetection because most biomolecules do not have upconversion properties. UCNs are also useful for light based therapy with enhanced efficiency, for example, photoactivation.

Quadratic general rotary unitized design for doping concentrations and up-conversion luminescence properties of Er{sup 3+}/Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} phosphors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Jiashi, E-mail: sunjs@dlmu.edu.cn; Shi, Linlin; Li, Shuwei

Highlights: • NaLa(MoO4)2: Er3+/Yb3+ phosphor is synthesized by solid state method. • QGRUD is first applied to the codoping concentration option. • Optimized phosphor presents more stable UC emissions than the commercial phosphor. - Abstract: It is still a great challenge that designing proper codoping concentrations of rare earth ions for achieving intensest expected emission from the studied phosphor. In this work, the quadratic general rotary unitized design (QGRUD) was introduced into the codoping concentration option of NaLa(MoO{sub 4}){sub 2}: Er{sup 3+}/Yb{sup 3+} phosphor for upconversion (UC) applications, and the optimum doping concentrations of Er{sup 3+} and Yb{sup 3+} formore » achieving maximum UC luminescence intensity, which is close to commercial NaYF{sub 4}:Er{sup 3+}/Yb{sup 3+} phosphor, were obtained. The two-photon process was assigned to the green UC emissions in the optimized NaLa(MoO{sub 4}){sub 2}: Er{sup 3+}/Yb{sup 3+} phosphor. It was also demonstrated that the optimized phosphor presented more stable upconversion emissions than the commercial NaYF{sub 4}:Er{sup 3+}/Yb{sup 3+} phosphor.« less

Multiple Temperature-Sensing Behavior of Green and Red Upconversion Emissions from Stark Sublevels of Er³⁺.

PubMed

Cao, Baosheng; Wu, Jinlei; Wang, Xuehan; He, Yangyang; Feng, Zhiqing; Dong, Bin

2015-12-10

Upconversion luminescence properties from the emissions of Stark sublevels of Er(3+) were investigated in Er(3+)-Yb(3+)-Mo(6+)-codoped TiO₂ phosphors in this study. According to the energy levels split from Er(3+), green and red emissions from the transitions of four coupled energy levels, ²H11/2(I)/²H11/2(II), ⁴S3/2(I)/⁴S3/2(II), ⁴F9/2(I)/⁴F9/2(II), and ²H11/2(I) + ²H11/2(II)/⁴S3/2(I) + ⁴S3/2(II), were observed under 976 nm laser diode excitation. By utilizing the fluorescence intensity ratio (FIR) technique, temperature-dependent upconversion emissions from these four coupled energy levels were analyzed at length. The optical temperature-sensing behaviors of sensing sensitivity, measurement error, and operating temperature for the four coupled energy levels are discussed, all of which are closely related to the energy gap of the coupled energy levels, FIR value, and luminescence intensity. Experimental results suggest that Er(3+)-Yb(3+)-Mo(6+)-codoped TiO₂ phosphor with four pairs of energy levels coupled by Stark sublevels provides a new and effective route to realize multiple optical temperature-sensing through a wide range of temperatures in an independent system.

Current advances in lanthanide ion (Ln(3+))-based upconversion nanomaterials for drug delivery.

PubMed

Yang, Dongmei; Ma, Ping'an; Hou, Zhiyou; Cheng, Ziyong; Li, Chunxia; Lin, Jun

2015-03-21

Lanthanide ion (Ln(3+))-based upconversion nano/micromaterials that emit higher-energy visible light when excited by low-energy NIR light have aroused considerable attention in the forefront of materials science and biomedical fields, which stems from their unique optical and chemical properties including minimum photodamage to living organisms, low autofluorescence, high signal-to-noise ratio and detection sensitivity, and high penetration depth in biological or environmental samples. Thus, Ln(3+)-based upconversion materials are rising new stars and are quickly emerging as potential candidates to revolutionize novel biomedical applications. In this review article, we mainly focus on the recent progress in various chemical syntheses of Ln(3+)-based upconversion nanomaterials, with special emphasis on their application in stimuli-response controlled drug release and subsequent therapy. Functional groups that are introduced into the stimuli-responsive system can respond to external triggers, such as pH, temperature, light, and even magnetic fields, which can regulate the movement of the pharmaceutical cargo and release the drug at a desired time and in a desired area. This is crucial to boost drug efficacy in cancer treatment while minimizing the side effects of cytotoxic drugs. Many multifunctional (magnetic/upconversion luminescence and porous) composite materials based on Ln(3+) have been designed for controlled drug delivery and multimodal bioimaging. Finally, the challenges and future opportunities for Ln(3+)-based upconversion materials are discussed.

Low-power upconversion in dye-doped polymer nanoparticles.

PubMed

Simon, Yoan C; Bai, Shuo; Sing, Michelle K; Dietsch, Hervé; Achermann, Marc; Weder, Christoph

2012-04-13

Examples of nanoscale low-power upconverting systems are rapidly increasing because of their potential application in numerous areas such as bioimaging or drug delivery. The fabrication of dye-doped cross-linked rubbery nanoparticles that exhibit upconversion even at relatively low power densities is reported here. The nanoparticles were prepared by surfactant-free emulsion polymerization of n-butylacrylate with divinylbenzene as a cross-linker, followed by dyeing of the resulting particles with a two-chromophore system composed of a palladium porphyrin sensitizer, and diphenylanthracene. Blue emission (≈440 nm) of these systems was observed upon excitation at 532 nm. In addition to their optical properties, the particles were characterized by electron microscopy and dynamic light scattering. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Upconversion luminescence from Er-N codoped of ZnO nanowires prepared by ion implantation method

NASA Astrophysics Data System (ADS)

Zhong, Kun; Xu, Jie; Su, Jing; Chen, Yu lin

2011-02-01

Nitrogen and erbium co-doped of ZnO nanowires (NWs) are fabricated by ion implantation and subsequent annealing in air. The incorporation of Er3+ and N+ ions is verified by energy dispersive X-ray spectroscopy (EDS) and Raman spectra. The samples exhibit upconversion photoluminescence around ∼550 nm and ∼660 nm under an excitation at 980 nm. It is discovered that the N-doped can drastically increase the upconversion photoluminescence intensity by modifying the local structure around Er3+ in ZnO matrix. The enhancement of the PL intensity by the N-doped is caused by the formation of ErO6-xNx octahedron complexes. With the increase of the annealing temperature (Ta), the Er3+ ions diffuse towards the surface of the NWs, which benefits the red emission and evokes the variation of intensity ratio owing to the existence of some organic groups.

Y2O3:Yb,Er@mSiO2-CuxS double-shelled hollow spheres for enhanced chemo-/photothermal anti-cancer therapy and dual-modal imaging

NASA Astrophysics Data System (ADS)

Yang, Dan; Yang, Guixin; Wang, Xingmei; Lv, Ruichan; Gai, Shili; He, Fei; Gulzar, Arif; Yang, Piaoping

2015-07-01

Multifunctional composites have gained significant interest due to their unique properties which show potential in biological imaging and therapeutics. However, the design of an efficient combination of multiple diagnostic and therapeutic modes is still a challenge. In this contribution, Y2O3:Yb,Er@mSiO2 double-shelled hollow spheres (DSHSs) with up-conversion fluorescence have been successfully prepared through a facile integrated sacrifice template method, followed by a calcination process. It is found that the double-shelled structure with large specific surface area and uniform shape is composed of an inner shell of luminescent Y2O3:Yb,Er and an outer mesoporous silica shell. Ultra small CuxS nanoparticles (about 2.5 nm) served as photothermal agents, and a chemotherapeutic agent (doxorubicin, DOX) was then attached onto the surface of mesoporous silica, forming a DOX-DSHS-CuxS composite. The composite exhibits high anti-cancer efficacy due to the synergistic photothermal therapy (PTT) induced by the attached CuxS nanoparticles and the enhanced chemotherapy promoted by the heat from the CuxS-based PTT when irradiated by 980 nm near-infrared (NIR) light. Moreover, the composite shows excellent in vitro and in vivo X-ray computed tomography (CT) and up-conversion fluorescence (UCL) imaging properties owing to the doped rare earth ions, thus making it possible to achieve the target of imaging-guided synergistic therapy.Multifunctional composites have gained significant interest due to their unique properties which show potential in biological imaging and therapeutics. However, the design of an efficient combination of multiple diagnostic and therapeutic modes is still a challenge. In this contribution, Y2O3:Yb,Er@mSiO2 double-shelled hollow spheres (DSHSs) with up-conversion fluorescence have been successfully prepared through a facile integrated sacrifice template method, followed by a calcination process. It is found that the double-shelled structure with large specific surface area and uniform shape is composed of an inner shell of luminescent Y2O3:Yb,Er and an outer mesoporous silica shell. Ultra small CuxS nanoparticles (about 2.5 nm) served as photothermal agents, and a chemotherapeutic agent (doxorubicin, DOX) was then attached onto the surface of mesoporous silica, forming a DOX-DSHS-CuxS composite. The composite exhibits high anti-cancer efficacy due to the synergistic photothermal therapy (PTT) induced by the attached CuxS nanoparticles and the enhanced chemotherapy promoted by the heat from the CuxS-based PTT when irradiated by 980 nm near-infrared (NIR) light. Moreover, the composite shows excellent in vitro and in vivo X-ray computed tomography (CT) and up-conversion fluorescence (UCL) imaging properties owing to the doped rare earth ions, thus making it possible to achieve the target of imaging-guided synergistic therapy. Electronic supplementary information (ESI) available: XRD patterns, zeta potential and FT-IR spectra of the samples obtained in different steps. N2 adsorption/desorption isotherm and the pore size distribution of Y2O3:Yb,Er@mSiO2-CuxS. Confocal images of HeLa cancer cells dyed with calcein AM and propidium iodide co-stained cells after treatment of Y2O3:Yb,Er@mSiO2-CuxS without or with 980 nm laser irradiation. CLSM images of HeLa cells incubated with DOX-Y2O3:Yb,Er@mSiO2-NH2-FA-CuxS-PEG and DOX-Y2O3:Yb,Er@mSiO2-NH2-CuxS-PEG for different times. The digital photographs of the H22 tumor-bearing Balb/c mice injected in situ with DOX-Y2O3:Yb,Er@mSiO2-NH2-FA-CuxS-PEG and DOX-Y2O3:Yb,Er@mSiO2-NH2-CuxS-PEG and the corresponding tumor sizes. See DOI: 10.1039/c5nr02269j

Simultaneous multiple wavelength upconversion in a core-shell nanoparticle for enhanced near infrared light harvesting in a dye-sensitized solar cell.

PubMed

Yuan, Chunze; Chen, Guanying; Li, Lin; Damasco, Jossana A; Ning, Zhijun; Xing, Hui; Zhang, Tianmu; Sun, Licheng; Zeng, Hao; Cartwright, Alexander N; Prasad, Paras N; Ågren, Hans

2014-10-22

The efficiency of most photovoltaic devices is severely limited by near-infrared (NIR) transmission losses. To alleviate this limitation, a new type of colloidal upconversion nanoparticles (UCNPs), hexagonal core-shell-structured β-NaYbF4:Er(3+)(2%)/NaYF4:Nd(3+)(30%), is developed and explored in this work as an NIR energy relay material for dye-sensitized solar cells (DSSCs). These UCNPs are able to harvest light energy in multiple NIR regions, and subsequently convert the absorbed energy into visible light where the DSSCs strongly absorb. The NIR-insensitive DSSCs show compelling photocurrent increases through binary upconversion under NIR light illumination either at 785 or 980 nm, substantiating efficient energy relay by these UCNPs. The overall conversion efficiency of the DSSCs was improved with the introduction of UCNPs under simulated AM 1.5 solar irradiation.

Enhancement of red upconversion emission of cubic phase NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Wei, E-mail: gaowei@xupt.edu.com; Dong, Jun, E-mail: dongjun@xupt.edu.cn; Liu, Jihong

Highlights: • The upconversion emission of Ho{sup 3+} ions was tuned from green to red. • The upconversion mechanism of Ho{sup 3+} ions was discussed based on emission spectrum. • The conversion efficiency between Ho{sup 3+} and Ce{sup 3+} were studied and calculated. - Abstract: The red upconversion emission of lanthanide-doped fluoride nanocrystals have great potential applications in color display and anticounterfeiting applications, especially for biological imaging and biomedical. In this work, a significant enhancement of red upconversion emission of Ho{sup 3+} ions was successfully obtained in the cubic phase NaLuF{sub 4} nanocrystals through codoping Ce{sup 3+} ions under NIRmore » 980 nm excitation. The ratio of red-to-green emission of Ho{sup 3+} ions was enhanced about 10-fold, which is due to two efficient cross relaxation processes derived from Ho{sup 3+} and Ce{sup 3+} ions promoted the red emission and quenched the green emission. The upconversion emission and luminescent colors of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} nanocrystals were carefully investigated by a confocal microscopy setup. The possible upconversion emission mechanism and conversion efficiency of cross relaxation between Ho{sup 3+} and Ce{sup 3+} ions were discussed in detail. The current study suggests that strong red emission of NaLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+}/Ce{sup 3+} nanomaterials can be used for color display and anticounterfeiting techniques.« less

Coupling of Ag Nanoparticle with Inverse Opal Photonic Crystals as a Novel Strategy for Upconversion Emission Enhancement of NaYF4: Yb(3+), Er(3+) Nanoparticles.

PubMed

Shao, Bo; Yang, Zhengwen; Wang, Yida; Li, Jun; Yang, Jianzhi; Qiu, Jianbei; Song, Zhiguo

2015-11-18

Rare-earth-ion-doped upconversion (UC) nanoparticles have generated considerable interest because of their potential application in solar cells, biological labeling, therapeutics, and imaging. However, the applications of UC nanoparticles were still limited because of their low emission efficiency. Photonic crystals and noble metal nanoparticles are applied extensively to enhance the UC emission of rare earth ions. In the present work, a novel substrate consisting of inverse opal photonic crystals and Ag nanoparticles was prepared by the template-assisted method, which was used to enhance the UC emission of NaYF4: Yb(3+), Er(3+) nanoparticles. The red or green UC emissions of NaYF4: Yb(3+), Er(3+) nanoparticles were selectively enhanced on the inverse opal substrates because of the Bragg reflection of the photonic band gap. Additionally, the UC emission enhancement of NaYF4: Yb(3+), Er(3+) nanoparticles induced by the coupling of metal nanoparticle plasmons and photonic crystal effects was realized on the Ag nanoparticles included in the inverse opal substrate. The present results demonstrated that coupling of Ag nanoparticle with inverse opal photonic crystals provides a useful strategy to enhance UC emission of rare-earth-ion-doped nanoparticles.

Multicolour synthesis in lanthanide-doped nanocrystals through cation exchange in water

NASA Astrophysics Data System (ADS)

Han, Sanyang; Qin, Xian; An, Zhongfu; Zhu, Yihan; Liang, Liangliang; Han, Yu; Huang, Wei; Liu, Xiaogang

2016-10-01

Meeting the high demand for lanthanide-doped luminescent nanocrystals across a broad range of fields hinges upon the development of a robust synthetic protocol that provides rapid, just-in-time nanocrystal preparation. However, to date, almost all lanthanide-doped luminescent nanomaterials have relied on direct synthesis requiring stringent controls over crystal nucleation and growth at elevated temperatures. Here we demonstrate the use of a cation exchange strategy for expeditiously accessing large classes of such nanocrystals. By combining the process of cation exchange with energy migration, the luminescence properties of the nanocrystals can be easily tuned while preserving the size, morphology and crystal phase of the initial nanocrystal template. This post-synthesis strategy enables us to achieve upconversion luminescence in Ce3+ and Mn2+-activated hexagonal-phased nanocrystals, opening a gateway towards applications ranging from chemical sensing to anti-counterfeiting.

Cubic sub-20 nm NaLuF(4)-based upconversion nanophosphors for high-contrast bioimaging in different animal species.

PubMed

Yang, Tianshe; Sun, Yun; Liu, Qian; Feng, Wei; Yang, Pengyuan; Li, Fuyou

2012-05-01

A new upconversion luminescence (UCL) nanophosphors based on host matrix of cubic NaLuF(4) with bright luminescence have been synthesized by a solvothermal method, facilitate the nanocrystals potential candidates for imaging in vivo, especially large-animals. The sub-20 nm NaLuF(4) co-doped Yb(3+) and Er(3+) (Tm(3+)) showed about 10-fold stronger UCL emission than that of corresponding hexagonal NaYF(4)-based nanocrystals with a 20 nm diameter. Near-infrared to near-infrared (NIR-to-NIR) UCL emission of PAA-coated NaLuF(4):20%Yb,1%Tm (PAA-Lu(Tm)) can penetrate >1.5 cm tissue of pork with high contrast. Based on super-strong UCL emission and deep penetration, PAA-Lu(Tm) as optical bioprobe has been demonstrated by in vivo UCL imaging of a normal black mouse, even rabbit with excellent signal-to-noise ratio. Furthermore, such cubic NaLuF(4)-based nanophosphor was applied in lymph node imaging of live Kunming mouse with rich white fur. Copyright © 2012 Elsevier Ltd. All rights reserved.

Temperature dependence of luminescence behavior in Er3+-doped BaY2F8 single crystal

NASA Astrophysics Data System (ADS)

Wang, Shuai; Ruan, Yongfeng; Tsuboi, Taiju; Tong, Hongshuang; Wang, Youfa; Zhang, Shouchao

2013-12-01

BaY2F8 single crystals doped with Er3+ ions have been grown by the temperature gradient method. The absorption, excitation and emission spectra for Er3+-doped BaY2F8 crystals were measured at room temperature (297 K) and 12 K. The effect of temperature on the luminescence intensity and effective bandwidth was investigated in the range of 12-297 K. The temperature dependence of the fluorescence intensity ratio (FIR) for the 522 nm emission (2H11/2→4I15/2 transition) and the 552 nm emission (4S3/2→4I15/2 transition) was also studied in the range of 12-297 K. Based on the fitting FIR curve, the value of the constant term B (2.25) was obtained. The fitting FIR curve and FIR equation may have a potential application in the temperature measurement. In addition, the up-conversion spectrum at room temperature was recorded under excitation of 980 nm and the up-conversion mechanism was analyzed in detail.

Near-infrared-emitting colloidal Ag2S quantum dots exhibiting upconversion luminescence

NASA Astrophysics Data System (ADS)

Zhang, Yanyan; Jiang, Danyu; Yang, Wei; Wang, Dandan; Zheng, Huiping; Du, Yuansheng; Li, Xi; Li, Qiang

2017-02-01

Ag2S quantum dots (QDs) coated with thioglycolic acid (Ag2S QDs-TGA) have been synthesized in an organic solvent via a stepwise addition of reagents. When excited by a 980 nm laser, the near-infrared-emitting colloidal Ag2S QDs-TGA exhibit upconversion luminescence (UCL). The observed photoluminescence (PL) was attributed to the presence of ligand-modified Ag2S on the QD surfaces. Hence, upon dilution of the solution, the PL intensity initially increased before subsequently decreasing, accompanied by a blue shift in the PL spectra. The PL phenomena can be attributed to the increase in the amount of ligand-modified Ag2S on the QD surfaces upon dilution, which in turn affected the fluorescence resonance energy transfer (FRET) and re-emission of the surface energy level. The relations between the emission intensity of Ag2S QDs-TGA and the excitation power are investigated, and the results confirm that the UCL in Ag2S QDs-TGA can be ascribed to a two-photon-assisted absorption process via a real energy state.

Light-activated endosomal escape using upconversion nanoparticles for enhanced delivery of drugs

NASA Astrophysics Data System (ADS)

Gnanasammandhan, Muthu Kumara; Bansal, Akshaya; Zhang, Yong

2013-02-01

Nanoparticle-based delivery of drugs has gained a lot of prominence recently but the main problem hampering efficient delivery of payload is the clearing or degradation of nanoparticles by endosomes. Various strategies have been used to overcome this issue and one such effective solution is Photochemical Internalization (PCI). This technique involves the activation of certain photosensitizing compounds by light, which accumulate specifically in the membranes of endocytic vesicles. The activated photosensitizers induce the formation of reactive oxygen species which in turn induces localized disruption of endosomal membranes. But the drawback of this technique is that it needs blue light for activation and hence confined to be used only in in-vitro systems due to the poor tissue penetration of blue light. Here, we report the use of Upconversion nanoparticles (UCNs) as a transducer for activation of the photosensitizer, TPPS 2a. NIR light has good tissue penetrating ability and thus enables PCI in greater depths. Highly monodisperse, uniformly-sized, sub-100 nm, biocompatible upconversion nanoparticles were synthesized with a mesoporous silica coating. These UCNs activated TPPS 2a efficiently in solution and in cells. Paclitaxel, an anti-cancer drug was used as a model drug and was loaded into the mesoporous silica coating. B16F0 cells transfected with drug-loaded UCNs and irradiated with NIR showed significantly higher nanoparticle uptake and in turn higher cell death caused by the delivered drug. This technique can be used to enhance the delivery of any therapeutic molecule and thus increase the therapeutic efficiency considerably.

Flexible transparent displays based on core/shell upconversion nanophosphor-incorporated polymer waveguides

PubMed Central

Park, Bong Je; Hong, A-Ra; Park, Suntak; Kyung, Ki-Uk; Lee, Kwangyeol; Seong Jang, Ho

2017-01-01

Core/shell (C/S)-structured upconversion nanophosphor (UCNP)-incorporated polymer waveguide-based flexible transparent displays are demonstrated. Bright green- and blue-emitting Li(Gd,Y)F4:Yb,Er and Li(Gd,Y)F4:Yb,Tm UCNPs are synthesized via solution chemical route. Their upconversion luminescence (UCL) intensities are enhanced by the formation of C/S structure with LiYF4 shell. The Li(Gd,Y)F4:Yb,Er/LiYF4 and Li(Gd,Y)F4:Yb,Tm/LiYF4 C/S UCNPs exhibit 3.3 and 2.0 times higher UCL intensities than core counterparts, respectively. In addition, NaGdF4:Yb,Tm/NaGdF4:Eu C/S UCNPs are synthesized and they show red emission via energy transfer and migration of Yb3+ → Tm3+ → Gd3+ → Eu3+. The C/S UCNPs are incorporated into bisphenol A ethoxylate diacrylate which is used as a core material of polymer waveguides. The fabricated stripe-type polymer waveguides are highly flexible and transparent (transmittance > 90% in spectral range of 443–900 nm). The polymer waveguides exhibit bright blue, green, and red luminescence, depending on the incorporated UCNPs into the polymer core, under coupling with a near infrared (NIR) laser. Moreover, patterned polymer waveguide-based display devices are fabricated by reactive ion etching process and they realize bright blue-, green-, and red-colored characters under coupling with an NIR laser. PMID:28368021

Flexible transparent displays based on core/shell upconversion nanophosphor-incorporated polymer waveguides

NASA Astrophysics Data System (ADS)

Park, Bong Je; Hong, A.-Ra; Park, Suntak; Kyung, Ki-Uk; Lee, Kwangyeol; Seong Jang, Ho

2017-04-01

Core/shell (C/S)-structured upconversion nanophosphor (UCNP)-incorporated polymer waveguide-based flexible transparent displays are demonstrated. Bright green- and blue-emitting Li(Gd,Y)F4:Yb,Er and Li(Gd,Y)F4:Yb,Tm UCNPs are synthesized via solution chemical route. Their upconversion luminescence (UCL) intensities are enhanced by the formation of C/S structure with LiYF4 shell. The Li(Gd,Y)F4:Yb,Er/LiYF4 and Li(Gd,Y)F4:Yb,Tm/LiYF4 C/S UCNPs exhibit 3.3 and 2.0 times higher UCL intensities than core counterparts, respectively. In addition, NaGdF4:Yb,Tm/NaGdF4:Eu C/S UCNPs are synthesized and they show red emission via energy transfer and migration of Yb3+ → Tm3+ → Gd3+ → Eu3+. The C/S UCNPs are incorporated into bisphenol A ethoxylate diacrylate which is used as a core material of polymer waveguides. The fabricated stripe-type polymer waveguides are highly flexible and transparent (transmittance > 90% in spectral range of 443-900 nm). The polymer waveguides exhibit bright blue, green, and red luminescence, depending on the incorporated UCNPs into the polymer core, under coupling with a near infrared (NIR) laser. Moreover, patterned polymer waveguide-based display devices are fabricated by reactive ion etching process and they realize bright blue-, green-, and red-colored characters under coupling with an NIR laser.

Recent advances in enhanced luminescence upconversion of lanthanide-doped NaYF4 phosphors

NASA Astrophysics Data System (ADS)

Kumar, Deepak; Verma, Kartikey; Verma, Shefali; Chaudhary, Babulal; Som, Sudipta; Sharma, Vishal; Kumar, Vijay; Swart, Hendrik C.

2018-04-01

NaYF4 is regarded as the best upconversion (UC) matrix owing to its low phonon energy, more chemical stability, and a superior refractive index. This review reports on the various synthesis techniques of lanthanide-doped NaYF4 phosphors for UC application. The UC intensity depends on different properties of the matrix and those are discussed in detail. Plasmon-enhanced luminescence UC of the lanthanide-doped NaYF4 core-shells structure is discussed based on a literature survey. The present review provides the information about how the UC intensity can be enhanced. The idea about the UC is then deliberately used for versatile applications such as luminescent materials, display devices, biomedical imaging and different security appliances. In addition, the present review demonstrates the recent trends of NaYF4 UC materials in solar cell devices. The role of NaYF4 phosphor to eradicate the spectral variance among the incident solar spectrum, semiconductor as well as the sub-band gap nature of the semiconductor materials is also discussed in detail. Considering the fact that the research status on NaYF4 phosphor for photovoltaic application is now growing, the present review is therefore very important to the researchers. More importantly, this may promote more interesting research platforms to investigate the realistic use of UC nanophosphors as spectral converters for solar cells.

Upconversion fluorescence tyrosine doped LaF3:Dy quantum dots useful in biolabeling and biotagging

NASA Astrophysics Data System (ADS)

Singh, Amit T.; Khandpekar, M. M.

2018-04-01

Water soluble hexahedral colloidal quantum dots (QDOTs) of Tyrosine doped LaF3:Dy have been synthesized by wet chemical route. The nanoparticles have been irradiated by microwave during synthesis for drying and also to reduce agglomeration. The coating of the LaF3:Dy nanoparticles by the amino acid tyrosine results in colloidal quantum dots. XRD studies indicates hexagonal lattice and confirms JCPDS data. The average particle size obtained by XRD and SEM are 22.89nm and 25.5nm respectively. The average sizes of nanorods obtained from TEM are 55 nm. The presence of elements has been verified with EDAX and ICP-AES technique. The SAED pattern of the samples shows sharp concentric rings indicating the crystalline nature of the synthesized nanoparticles. The FTIR spectra have been used to study the surface modification of the nanoparticles. The optical studies have been done using UV-visible and PL spectra. The PL spectra showed upconversion nature of the synthesized nanoparticles with sharp emission at 618 nm. The nanoparticles synthesized have potential application as biomaterials in bio imaging and biotagging.

Nanoparticles as multimodal photon transducers of ionizing radiation

NASA Astrophysics Data System (ADS)

Pratt, Edwin C.; Shaffer, Travis M.; Zhang, Qize; Drain, Charles Michael; Grimm, Jan

2018-05-01

In biomedical imaging, nanoparticles combined with radionuclides that generate Cerenkov luminescence are used in diagnostic imaging, photon-induced therapies and as activatable probes. In these applications, the nanoparticle is often viewed as a carrier inert to ionizing radiation from the radionuclide. However, certain phenomena such as enhanced nanoparticle luminescence and generation of reactive oxygen species cannot be completely explained by Cerenkov luminescence interactions with nanoparticles. Herein, we report methods to examine the mechanisms of nanoparticle excitation by radionuclides, including interactions with Cerenkov luminescence, β particles and γ radiation. We demonstrate that β-scintillation contributes appreciably to excitation and reactivity in certain nanoparticle systems, and that excitation by radionuclides of nanoparticles composed of large atomic number atoms generates X-rays, enabling multiplexed imaging through single photon emission computed tomography. These findings demonstrate practical optical imaging and therapy using radionuclides with emission energies below the Cerenkov threshold, thereby expanding the list of applicable radionuclides.

NIR-triggered high-efficient photodynamic and chemo-cascade therapy using caspase-3 responsive functionalized upconversion nanoparticles.

PubMed

Zhao, Na; Wu, Baoyan; Hu, Xianglong; Xing, Da

2017-10-01

Stimuli-responsive nanoparticles with multiple therapeutic/diagnostic functions are highly desirable for effective tumor treatment. Herein novel caspase-3 responsive functionalized upconversion nanoparticles (CFUNs) were fabricated with three-in-one functional integration: near-infrared (NIR) triggered photodynamic damage along with caspase-3 activation, subsequent caspase-3 responsive drug release, and cascade chemotherapeutic activation. CFUNs were formulated from the self-assembly of caspase-3 responsive doxorubicin (DOX) prodrug tethered with DEVD peptide (DEVD-DOX), upconversion nanoparticles (UCNP), a photosensitizer (pyropheophorbide-a methyl ester, MPPa), and tumor-targeting cRGD-PEG-DSPE to afford multifunctional CFUNs, MPPa/UCNP-DEVD-DOX/cRGD. Upon cellular uptake and NIR irradiation, the visible light emission of UCNP could excite MPPa to produce reactive oxygen species for photodynamic therapy (PDT) along with the activation of caspase-3, which further cleaved DEVD peptide to release DOX within tumor cells, thus accomplishing NIR-triggered PDT and cascade chemotherapy. CFUNs presented silent therapeutic potency and negligible cytotoxicity in the dark, whereas in vitro and in vivo experiments demonstrated the NIR-triggered cascade therapeutic activation and tumor inhibition due to consecutive PDT and chemotherapy. Current NIR-activated cascade tumor therapy with two distinct mechanisms is significantly favorable to overcome multidrug resistance and tumor heterogeneity for persistent tumor treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of near-infrared luminescent gold nanoclusters for detection of macrophages

PubMed Central

Sapozhnikova, Veronika; Willsey, Brian; Asmis, Reto; Wang, Tianyi; Jenkins, James Travis; Mancuso, Jacob; Ma, Li Leo; Kuranov, Roman; Milner, Thomas E.; Johnston, Keith

2012-01-01

Abstract. We determined the effect of aggregation and coating thickness of gold on the luminescence of nanoparticles engulfed by macrophages and in gelatin phantoms. Thin gold-coated iron oxide nanoclusters (nanoroses) have been developed to target macrophages to provide contrast enhancement for near-infrared optical imaging applications. We compare the brightness of nanoroses luminescent emissions in response to 635 nm laser excitation to other nanoparticles including nanoshells, nanorods, and Cy5 conjugated iron oxide nanoparticles. Luminescent properties of all these nanoparticles were investigated in monomeric and aggregated form in gelatin phantoms and primary macrophage cell cultures using confocal microscopy. Aggregation of the gold nanoparticles increased luminescence emission and correlated with increased surface mass of gold per nanoparticle (nanoshells 37±14.30×10−3 brightness with 1.23×10−4 wt of gold (g)/nanoparticle versus original nanorose 1.45±0.37×10−3 with 2.10×10−16 wt of gold/nanoparticle, p<0.05). Nanoshells showed greater luminescent intensity than original nanoroses or Cy5 conjugated iron oxide nanoparticles when compared as nanoparticles per macrophage (38±10 versus 11±2.8 versus 17±6.5, p<0.05, respectively, ANOVA), but showed relatively poor macrophage uptake (1025±128 versus 7549±236 versus 96,000  nanoparticles/cell, p<0.05, student t-test nanoshells versus nanoroses). Enhancement of gold fluorescent emissions by nanoparticles can be achieved by reducing the thickness of the gold coating, by clustering the gold on the surface of the nanoparticles (nanoshells), and by clustering the gold nanoparticles themselves. PMID:22463038

Towards Efficient Spectral Converters through Materials Design for Luminescent Solar Devices.

PubMed

McKenna, Barry; Evans, Rachel C

2017-07-01

Single-junction photovoltaic devices exhibit a bottleneck in their efficiency due to incomplete or inefficient harvesting of photons in the low- or high-energy regions of the solar spectrum. Spectral converters can be used to convert solar photons into energies that are more effectively captured by the photovoltaic device through a photoluminescence process. Here, recent advances in the fields of luminescent solar concentration, luminescent downshifting, and upconversion are discussed. The focus is specifically on the role that materials science has to play in overcoming barriers in the optical performance in all spectral converters and on their successful integration with both established (e.g., c-Si, GaAs) and emerging (perovskite, organic, dye-sensitized) cell types. Current challenges and emerging research directions, which need to be addressed for the development of next-generation luminescent solar devices, are also discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rare earth-doped lead borate glasses and transparent glass-ceramics: structure-property relationship.

PubMed

Pisarski, W A; Pisarska, J; Mączka, M; Lisiecki, R; Grobelny, Ł; Goryczka, T; Dominiak-Dzik, G; Ryba-Romanowski, W

2011-08-15

Correlation between structure and optical properties of rare earth ions in lead borate glasses and glass-ceramics was evidenced by X-ray-diffraction, Raman, FT-IR and luminescence spectroscopy. The rare earths were limited to Eu(3+) and Er(3+) ions. The observed BO(3)↔BO(4) conversion strongly depends on the relative PbO/B(2)O(3) ratios in glass composition, giving important contribution to the luminescence intensities associated to (5)D(0)-(7)F(2) and (5)D(0)-(7)F(1) transitions of Eu(3+). The near-infrared luminescence and up-conversion spectra for Er(3+) ions in lead borate glasses before and after heat treatment were measured. The more intense and narrowing luminescence lines suggest partial incorporation of Er(3+) ions into the orthorhombic PbF(2) crystalline phase, which was identified using X-ray diffraction analysis. Copyright © 2010 Elsevier B.V. All rights reserved.

Energy Migration Upconversion in Manganese(II)-Doped Nanoparticles.

PubMed

Li, Xiyan; Liu, Xiaowang; Chevrier, Daniel M; Qin, Xian; Xie, Xiaoji; Song, Shuyan; Zhang, Hongjie; Zhang, Peng; Liu, Xiaogang

2015-11-02

We report the synthesis and characterization of cubic NaGdF4:Yb/Tm@NaGdF4:Mn core-shell structures. By taking advantage of energy transfer through Yb→Tm→Gd→Mn in these core-shell nanoparticles, we have realized upconversion emission of Mn(2+) at room temperature in lanthanide tetrafluoride based host lattices. The upconverted Mn(2+) emission, enabled by trapping the excitation energy through a Gd(3+) lattice, was validated by the observation of a decreased lifetime from 941 to 532 μs in the emission of Gd(3+) at 310 nm ((6)P(7/2)→(8)S(7/2)). This multiphoton upconversion process can be further enhanced under pulsed laser excitation at high power densities. Both experimental and theoretical studies provide evidence for Mn(2+) doping in the lanthanide-based host lattice arising from the formation of F(-) vacancies around Mn(2+) ions to maintain charge neutrality in the shell layer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Two-photon up-conversion fluorescence of a neodymium organic framework Nd(BTC)].

PubMed

Xu, Hui; Jin, Run-zhi; Wu, Chun-yang; Yang, Yu; Qian, Guo-dong

2008-08-01

In the present work, a neodymium organic framework Nd(BTC) was synthesized by the solvothermal reaction of Nd(NO3)3 x 5H2O and H3BTC (BTC = 1,3,5-benzenetricarboxylate) in mixed solvents of DMF, ethanol and water, and was identified by elemental analysis. This MOF complex was characterized using X-ray diffraction (XRD), thermogravimetry-differential scanning calorimetry (TGA-DSC) analysis, UV-visible absorption spectra and fluorescence spectra. This polycrystalline powder lost DMF and H2O when heated to 120 degrees C, then remained stable till the temperature reached 500 degrees C. Near infrared fluorescence at 1064 nm due to the 4 F3/2--> 4 I11/2 transition of Nd3+ ions was exhibited when excited by 808 nm laser beam. It was also been found that up-conversion fluorescence of Nd(BTC) peaked at about 450 nm due to 2 D5/2 -->4 I11/2 transition of Nd3+ ions can be observed under the excitation of a 580 nm laser line. The mechanism of the up-conversion fluorescence of Nd(BTC) at around 450 nm under the excitation of 580 nm laser can be ascribed to both excited-state absorption and energy transfer up-conversion. This result indicated that such MOF can be employed as an up-conversion luminescence material in many potential application areas such as bio-labeling and fluorescence image.

Upconversion nanoparticle-based fluorescence resonance energy transfer assay for organophosphorus pesticides.

PubMed

Long, Qian; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

2015-06-15

This paper reports a novel nanosensor for organophosphorus pesticides based on the fluorescence resonance energy transfer (FRET) between NaYF4:Yb,Er upconversion nanoparticles (UCNPs) and gold nanoparticles (AuNPs). The detection mechanism is based on the facts that AuNPs quench the fluorescence of UCNPs and organophosphorus pesticides (OPs) inhibit the activity of acetylcholinesterase (AChE) which catalyzes the hydrolysis of acetylthiocholine (ATC) into thiocholine. Under the optimized conditions, the logarithm of the pesticides concentration was proportional to the inhibition efficiency. The detection limits of parathion-methyl, monocrotophos and dimethoate reached 0.67, 23, and 67 ng/L, respectively. Meanwhile, the biosensor shows good sensitivity, stability, and could be successfully applied to detection of OPs in real food samples, suggesting the biosensor has potentially extensive application clinic diagnoses assays. Copyright © 2014 Elsevier B.V. All rights reserved.

Upconversion luminescence, intensity saturation effect, and thermal effect in Gd{sub 2}O{sub 3}:Er{sup 3},Yb{sup 3+} nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei Yanqiang; Song Hongwei; Yang Linmei

2005-11-01

In this paper, the upconversion luminescent properties of Gd{sub 2}O{sub 3}:Er{sup 3+},Yb{sup 3+} nanowires as a function of Yb concentration and excitation power were studied under 978-nm excitation. The results indicated that the relative intensity of the red emission ({sup 4}F{sub 9/2}-{sup 4}I{sub 15/2}) increased with increasing the Yb{sup 3+} concentration, while that of the green emission ({sup 4}S{sub 3/2}/{sup 2}H{sub 11/2}-{sup 4}I{sub 15/2}) decreased. As a function of excitation power in ln-ln plot, the green emission of {sup 4}S{sub 3/2}-{sup 4}I{sub 15/2} yielded a slope of {approx}2, while the red emission of {sup 4}F{sub 9/2}-{sup 4}I{sub 15/2} yielded amore » slope of {approx}1. Moreover, the slope decreased with increasing the Yb{sup 3+} concentration. This was well explained by the expanded theory of competition between linear decay and upconversion processes for the depletion of the intermediate excited states. As the excitation power density was high enough, the emission intensity of upconversion decreased due to thermal quenching. The thermal effect caused by the exposure of the 978-nm laser was studied according to the intensity ratio of {sup 2}H{sub 11/2}-{sup 4}I{sub 15/2} to {sup 4}S{sub 3/2}-{sup 4}I{sub 15/2}. The practical sample temperature at the exposed spot as a function of excitation power and Yb{sup 3+} concentration was deduced. The result indicated that at the irradiated spot (0.5x0.5 mm{sup 2}) the practical temperature considerably increased.« less

Upconverting core-shell nanocrystals with high quantum yield under low irradiance: On the role of isotropic and thick shells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischer, Stefan; Goldschmidt, Jan Christoph; Johnson, Noah J. J.

2015-11-21

Colloidal upconverter nanocrystals (UCNCs) that convert near-infrared photons to higher energies are promising for applications ranging from life sciences to solar energy harvesting. However, practical applications of UCNCs are hindered by their low upconversion quantum yield (UCQY) and the high irradiances necessary to produce relevant upconversion luminescence. Achieving high UCQY under practically relevant irradiance remains a major challenge. The UCQY is severely limited due to non-radiative surface quenching processes. We present a rate equation model for migration of the excitation energy to show that surface quenching does not only affect the lanthanide ions directly at the surface but also manymore » other lanthanide ions quite far away from the surface. The average migration path length is on the order of several nanometers and depends on the doping as well as the irradiance of the excitation. Using Er{sup 3+}-doped β-NaYF{sub 4} UCNCs, we show that very isotropic and thick (∼10 nm) β-NaLuF{sub 4} inert shells dramatically reduce the surface-related quenching processes, resulting in much brighter upconversion luminescence at simultaneously considerably lower irradiances. For these UCNCs embedded in poly(methyl methacrylate), we determined an internal UCQY of 2.0% ± 0.2% using an irradiance of only 0.43 ± 0.03 W/cm{sup 2} at 1523 nm. Normalized to the irradiance, this UCQY is 120× higher than the highest values of comparable nanomaterials in the literature. Our findings demonstrate the important role of isotropic and thick shells in achieving high UCQY at low irradiances from UCNCs. Additionally, we measured the additional short-circuit current due to upconversion in silicon solar cell devices as a proof of concept and to support our findings determined using optical measurements.« less

Facile synthesis of upconversion nanoparticles with high purity using lanthanide oleate compounds

NASA Astrophysics Data System (ADS)

Kang, Ning; Ai, Chao-Chao; Zhou, Ya-Ming; Wang, Zuo; Ren, Lei

2018-02-01

A novel strategy for preparing highly pure NaYF4-based upconversion nanoparticles (UCNPs) was developed using lanthanide oleate compounds [Ln(OA)3] as the precursor, denoted as the Ln-OA preparation method. Compared to the conventional solvothermal method for synthesizing UCNPs using lanthanide chloride compounds (LnCl3) as the precursor (denoted as the Ln-Cl method), the Ln-OA strategy exhibited the merits of high purity, reduced purification process and a uniform size in preparing core and core-shell UCNPs excited by a 980 or 808 nm near infrared (NIR) laser. This work sheds new insight on the preparation of UCNPs and promotes their application in biomedical fields.

Morphology evolution and pure red upconversion mechanism of β-NaLuF4 crystals.

PubMed

Lin, Hao; Xu, Dekang; Li, Anming; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

2016-06-16

A series of β-NaLuF4 crystals were synthesized via a hydrothermal method. Hexagonal phase microdisks, microprisms, and microtubes were achieved by simply changing the amount of citric acid in the initial reaction solution. Pure red upconversion (UC) luminescence can be observed in β-NaLuF4:Yb(3+), Tm(3+), Er(3+) and Li(+) doped β-NaLuF4:20% Yb(3+), 1% Tm(3+), 20% Er(3+). Based on the rate equations, we report the theoretical model about the pure red UC mechanism in Yb(3+)/Tm(3+)/Er(3+) doped system. It is proposed that the pure red UC luminescence is mainly ascribed to the energy transfer UC from Tm(3+):(3)F4 → (3)H6 to Er(3+):(4)I11/2 → (4)F9/2 and the cross-relaxation (CR) effect [Er(3+):(4)S3/2 + (4)I15/2 → (4)I9/2 + (4)I13/2] rather than the long-accepted mechanism [CR process among Er(3+):(4)F7/2 + (4)I11/2 → (4)F9/2 + (4)F9/2]. In addition, compared to the Li(+)-free counterpart, the pure red UC luminescence in β-NaLuF4:20% Yb(3+), 1% Tm(3+), 20% Er(3+) with 15 mol% Li(+) doping is enhanced by 13.7 times. This study provides a general and effective approach to obtain intense pure red UC luminescence, which can be applied to other synthetic strategies.

Morphology evolution and pure red upconversion mechanism of β-NaLuF4 crystals

PubMed Central

Lin, Hao; Xu, Dekang; Li, Anming; Teng, Dongdong; Yang, Shenghong; Zhang, Yueli

2016-01-01

A series of β-NaLuF4 crystals were synthesized via a hydrothermal method. Hexagonal phase microdisks, microprisms, and microtubes were achieved by simply changing the amount of citric acid in the initial reaction solution. Pure red upconversion (UC) luminescence can be observed in β-NaLuF4:Yb3+, Tm3+, Er3+ and Li+ doped β-NaLuF4:20% Yb3+, 1% Tm3+, 20% Er3+. Based on the rate equations, we report the theoretical model about the pure red UC mechanism in Yb3+/Tm3+/Er3+ doped system. It is proposed that the pure red UC luminescence is mainly ascribed to the energy transfer UC from Tm3+:3F4 → 3H6 to Er3+:4I11/2 → 4F9/2 and the cross-relaxation (CR) effect [Er3+:4S3/2 + 4I15/2 → 4I9/2 + 4I13/2] rather than the long-accepted mechanism [CR process among Er3+:4F7/2 + 4I11/2 → 4F9/2 + 4F9/2]. In addition, compared to the Li+-free counterpart, the pure red UC luminescence in β-NaLuF4:20% Yb3+, 1% Tm3+, 20% Er3+ with 15 mol% Li+ doping is enhanced by 13.7 times. This study provides a general and effective approach to obtain intense pure red UC luminescence, which can be applied to other synthetic strategies. PMID:27306720

Security printing of covert quick response codes using upconverting nanoparticle inks

NASA Astrophysics Data System (ADS)

Meruga, Jeevan M.; Cross, William M.; May, P. Stanley; Luu, QuocAnh; Crawford, Grant A.; Kellar, Jon J.

2012-10-01

Counterfeiting costs governments and private industries billions of dollars annually due to loss of value in currency and other printed items. This research involves using lanthanide doped β-NaYF4 nanoparticles for security printing applications. Inks comprised of Yb3+/Er3+ and Yb3+/Tm3+ doped β-NaYF4 nanoparticles with oleic acid as the capping agent in toluene and methyl benzoate with poly(methyl methacrylate) (PMMA) as the binding agent were used to print quick response (QR) codes. The QR codes were made using an AutoCAD file and printed with Optomec direct-write aerosol jetting®. The printed QR codes are invisible under ambient lighting conditions, but are readable using a near-IR laser, and were successfully scanned using a smart phone. This research demonstrates that QR codes, which have been used primarily for information sharing applications, can also be used for security purposes. Higher levels of security were achieved by printing both green and blue upconverting inks, based on combinations of Er3+/Yb3+ and Tm3+/Yb3+, respectively, in a single QR code. The near-infrared (NIR)-to-visible upconversion luminescence properties of the two-ink QR codes were analyzed, including the influence of NIR excitation power density on perceived color, in term of the CIE 1931 chromaticity index. It was also shown that this security ink can be optimized for line width, thickness and stability on different substrates.

Security printing of covert quick response codes using upconverting nanoparticle inks.

PubMed

Meruga, Jeevan M; Cross, William M; Stanley May, P; Luu, QuocAnh; Crawford, Grant A; Kellar, Jon J

2012-10-05

Counterfeiting costs governments and private industries billions of dollars annually due to loss of value in currency and other printed items. This research involves using lanthanide doped β-NaYF(4) nanoparticles for security printing applications. Inks comprised of Yb(3+)/Er(3+) and Yb(3+)/Tm(3+) doped β-NaYF(4) nanoparticles with oleic acid as the capping agent in toluene and methyl benzoate with poly(methyl methacrylate) (PMMA) as the binding agent were used to print quick response (QR) codes. The QR codes were made using an AutoCAD file and printed with Optomec direct-write aerosol jetting(®). The printed QR codes are invisible under ambient lighting conditions, but are readable using a near-IR laser, and were successfully scanned using a smart phone. This research demonstrates that QR codes, which have been used primarily for information sharing applications, can also be used for security purposes. Higher levels of security were achieved by printing both green and blue upconverting inks, based on combinations of Er(3+)/Yb(3+) and Tm(3+)/Yb(3+), respectively, in a single QR code. The near-infrared (NIR)-to-visible upconversion luminescence properties of the two-ink QR codes were analyzed, including the influence of NIR excitation power density on perceived color, in term of the CIE 1931 chromaticity index. It was also shown that this security ink can be optimized for line width, thickness and stability on different substrates.

A temperature sensor based on the enhanced upconversion luminescence of Li+ doped NaLuF4:Yb3+,Tm3+/Er3+ nano/microcrystals.

PubMed

Qiang, Qinping; Du, Shanshan; Ma, Xinlong; Chen, Wenbo; Zhang, Gangyi; Wang, Yuhua

2018-05-09

In this paper, fluorescent and optical temperature sensing bi-functional Li+-doping NaLuF4:Ln (Ln = Yb3+, Tm3+/Er3+) nanocrystals were synthesized via a simple hydrothermal method using oleic acid as a capping ligand. The crystal phase, size, upconversion (UC) properties, and optical temperature sensing characteristics of the crystals can be easily modified by Li+ doping. The results reveal that additional Li+ can promote the transformation from the hexagonal phase to the cubic phase and reduce the size of the nanocrystals. In addition, NaLuF4:Ln (Ln = Yb3+, Tm3+, Li+) nanocrystals present efficient near infrared (NIR) emission, which is beneficial for in vivo biomedical applications due to the increased penetration depth and low radiation damage of NIR light in bio-tissues. More importantly, under 980 nm excitation, the temperature dependent UCL from the 2H11/2 and 4S3/2 levels of Er3+ ions in NaLuF4:Yb3+,Er3+,Li+ microcrystals was investigated systematically. The fluorescence intensity ratios (FIR) of the pairs of thermally coupled levels were studied as a function of temperature in the range of 298-523 K. The maximum sensor sensitivities were found to be about 0.0039 K-1 (523 K) by exploiting the UC emissions from the 2H11/2 and 4S3/2 levels. This suggests that the Li+-doped upconversion luminescence (UCL) materials are promising prototypes for application as multi-mode probes for use in bio-separation and optical thermometers.

Highly efficient up-conversion and bright white light in RE co-doped KYF4 nanocrystals in sol-gel silica matrix

NASA Astrophysics Data System (ADS)

Méndez-Ramos, J.; Yanes, A. C.; Santana-Alonso, A.; del-Castillo, J.

2013-01-01

Transparent nano-glass-ceramics comprising Yb3+, Er3+ and Tm3+ co-doped KYF4 nanocrystals have been developed from sol-gel method. A structural analysis by means of X-ray diffraction confirmed the precipitation of cubic KYF4 nanocrystals into a silica matrix. Visible luminescence has been analyzed as function of treatment temperature of precursor sol-gel glasses. Highly efficient up-conversion emissions have been obtained under 980 nm excitation and studied by varying the doping level, processing temperature and pump power. Color tuneability has been quantified in terms of CIE diagram and in particular, a white-balanced overall emission has been achieved for a certain doping level and thermal treatment.

Efficient near-infrared up-conversion photoluminescence in carbon nanotubes

PubMed Central

Akizuki, Naoto; Aota, Shun; Mouri, Shinichiro; Matsuda, Kazunari; Miyauchi, Yuhei

2015-01-01

Photoluminescence phenomena normally obey Stokes' law of luminescence according to which the emitted photon energy is typically lower than its excitation counterparts. Here we show that carbon nanotubes break this rule under one-photon excitation conditions. We found that the carbon nanotubes exhibit efficient near-infrared photoluminescence upon photoexcitation even at an energy lying >100–200 meV below that of the emission at room temperature. This apparently anomalous phenomenon is attributed to efficient one-phonon-assisted up-conversion processes resulting from unique excited-state dynamics emerging in an individual carbon nanotube with accidentally or intentionally embedded localized states. These findings may open new doors for energy harvesting, optoelectronics and deep-tissue photoluminescence imaging in the near-infrared optical range. PMID:26568250

Polarization-dependent extraordinary optical transmission from upconversion nanoparticles.

PubMed

Wang, Peng Hui; Salcedo, Walter J; Pichaandi, Jothirmayanantham; van Veggel, Frank C J M; Brolo, Alexandre G

2015-11-21

Enhanced upconversion (UC) emission was experimentally demonstrated using gold double antenna nanoparticles coupled to nanoslits in gold films. The transmitted red emission from UC ytterbium and erbium co-doped sodium yttrium fluoride (NaYF4:Yb(3+)/Er(3+)) nanoparticles (UC NPs) at ∼665 nm (excited with a 980 nm diode laser) was enhanced relative to the green emission at ∼550 nm. The relatively enhanced UC NP emission could be tuned by the different polarization-dependent extraordinary optical transmission modes coupled to the gold nanostructures. Finite-difference time-domain calculations suggest that the preferential enhanced UC emission is related to a combination of different surface plasmon mode excitation coupling to cavity Fabry-Perot interactions. A maximum UC enhancement of 6-fold was measured for nanoslit arrays in the absence of the double antennas. In the presence of the double nanoantennas inside the nanoslits, the UC enhancement was between 2- and 4-fold, depending on the experimental conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Li-Ping; Zhang, Qiang; State Key Laboratory of Pollution Control and Resource Reuse

Graphical abstract: Lanthanide ions doped bare earth rare earth fluoride nanocrystals are synthesized by hydrothermal technology and characterized. The down/up-conversion luminescence of them are discussed. - Highlights: • Mixed hydrothermal system H{sub 2}O–OA (EDA)–O-A(LO-A) is used for synthesis. • Barium rare earth fluoride nanocrystals are synthesized comprehensively. • Luminescence for down-conversion and up-conversion are obtained for these systems. - Abstract: Mixed hydrothermal system H{sub 2}O–OA (EDA)–O-A(LO-A) is developed to synthesize barium rare earth fluorides nanocrystals (OA = oleylamine, EDA = ethylenediamine, O-A = oleic acid and LO-A = linoleic acid). They are presented as BaREF{sub 5} (RE = Ce, Pr,more » Nd, Eu, Gd, Tb, Dy, Y, Tm, Lu) and Ba{sub 2}REF{sub 7} (RE = La, Sm, Ho, Er, Yb). The influence of reaction parameters (rare earth species, hydrothermal system and temperature) is checked on the phase and shape evolution of the fluoride nanocrystals. It is found that reaction time and temperature of these nanocrystals using EDA (180 °C, 6 h) is lower than those of them using OA (220 °C, 10 h). The photoluminescence properties of these fluorides activated by some rare earth ions (Nd{sup 3+}, Eu{sup 3+}, Tb{sup 3+}) are studied, and especially up-conversion luminescence of the four fluoride nanocrystal systems (Ba{sub 2}LaF{sub 7}:Yb, Tm(Er), Ba{sub 2}REF{sub 7}:Yb, Tm(Er) (RE = Gd, Y, Lu)) is observed.« less

Tuning the luminescence of ZnO:Eu nanoparticles for applications in biology and medicine

NASA Astrophysics Data System (ADS)

Kaszewski, Jarosław; Kiełbik, Paula; Wolska, Ewelina; Witkowski, Bartłomiej; Wachnicki, Łukasz; Gajewski, Zdzisław; Godlewski, Marek; Godlewski, Michał M.

2018-06-01

Zinc oxide nanoparticles were synthesized with microwave hydrothermal technique and tested as luminescent contrast for biological imaging. Luminescence was activated by Eu3+ ions embedded in the nanoparticle matrix in the increasing concentrations of 1, 5 and 10 %mol. It was found that europium did not create a separate crystalline phase up to the concentration as high as 5 %mol. However, Eu3+ ions did not substitute Zn2+ in the host lattice, but allocated in the low symmetry environment. It was proposed that europium was locating in the inter-grain space or on the surface of nanoparticles. The luminescence intensity in ZnO:Eu, as well as the size of particles, increased with the Eu ion concentration. Moreover, in 10 %mol Eu sample, the separate phase of Eu-hydroxide was identified with crystals of micrometre length. Interestingly, in vivo study revealed, that contrary to the in silico experiments, following gastric gavage, the brightest nanoparticle-related luminescence signal was observed at 1 %mol. concentration of Eu. Since the alimentary uptake of nanoparticles was related to their size, we concluded that the increase in luminescence at 5 and 10 %mol. Eu concentrations was associated with the largest ZnO:Eu and Eu-hydroxide particles that did not cross the gastrointestinal barrier.

Structural transformation and photoluminescence modification of AgInS2 nanoparticles induced by ZnS shell formation

NASA Astrophysics Data System (ADS)

Hamanaka, Yasushi; Yukitoki, Daichi; Kuzuya, Toshihiro

2015-09-01

AgInS2 nanoparticles were capped by ZnS via a widely used procedure to fabricate core/shell nanoparticles with highly efficient luminescence. The nanoparticle structures were investigated by ultrahigh-resolution analytical electron microscopy. We found that Zn-Ag-In-S nanoparticles were created by ZnS capping at ˜480 K, which suggests that the luminescence enhancement reported for such core/shell nanoparticles is not caused by the passivation of surface defects by ZnS shells but by Zn doping. Quasi-core/shell nanoparticles could be obtained by ZnS capping without heating. However, their luminescence efficiency remained unchanged, indicating that surface passivation was ineffective when ZnS shells were formed at room temperature.

Multicolored redox active upconverter cerium oxide nanoparticle for bio-imaging and therapeutics†

PubMed Central

Babu, Suresh; Cho, Jung-Hyun; Dowding, Janet M.; Heckert, Eric; Komanski, Chris; Das, Soumen; Colon, Jimmie; Baker, Cheryl H.; Bass, Michael; Self, William T.; Seal, Sudipta

2011-01-01

Cytocompatible, co-doped cerium oxide nanoparticles exhibited strong upconversion properties that were found to kill lung cancer cells by inducing apoptosis thereby demonstrating the potential to be used as clinical contrast agents for imaging and as therapeutic agents for treatment of cancer. PMID:20683524

808 nm-excited upconversion nanoprobes with low heating effect for targeted magnetic resonance imaging and high-efficacy photodynamic therapy in HER2-overexpressed breast cancer.

PubMed

Zeng, Leyong; Pan, Yuanwei; Zou, Ruifen; Zhang, Jinchao; Tian, Ying; Teng, Zhaogang; Wang, Shouju; Ren, Wenzhi; Xiao, Xueshan; Zhang, Jichao; Zhang, Lili; Li, Aiguo; Lu, Guangming; Wu, Aiguo

2016-10-01

To avoid the overheating effect of excitation light and improve the efficacy of photodynamic therapy (PDT) of upconversion nanoplatform, a novel nanoprobe based on 808 nm-excited upconversion nanocomposites (T-UCNPs@Ce6@mSiO2) with low heating effect and deep penetration has been successfully constructed for targeted upconversion luminescence, magnetic resonance imaging (MRI) and high-efficacy PDT in HER2-overexpressed breast cancer. In this nanocomposite, photosensitizers (Ce6) were covalently conjugated inside of mesoporous silica to enhance the PDT efficacy by shortening the distance of fluorescence resonance energy transfer and to decrease the cytotoxicity by preventing the undesired leakage of Ce6. Compared with UCNPs@mSiO2@Ce6, UCNPs@Ce6@mSiO2 greatly promoted the singlet oxygen generation and amplified the PDT efficacy under the excitation of 808 nm laser. Importantly, the designed nanoprobe can greatly improve the uptake of HER2-positive cells and tumors by modifying the site-specific peptide, and the in vivo experiments showed excellent MRI and PDT via intravenous injection by modeling MDA-MB-435 tumor-bearing nude mice. Our strategy may provide an effective solution for overcoming the heating effect and improving the PDT efficacy of upconversion nanoprobes, and has potential application in visualized theranostics of HER2-overexpressed breast cancer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improvement Photocatalytic Activity of P25 by Modification with a Rare Earth-Free Upconversion Nanocrystal.

PubMed

Yin, Dongguang; Liu, Yumin; Zhao, Feifei; Zhang, Xinyu; Zhang, Tingting; Wu, Chenglong; Chang, Na; Chen, Zhiwen

2018-05-01

It has been reported that coupling TiO2 with rare earth upconversion nanocrystals (UCNCs) is an efficient strategy to significantly improve photocatalytic activity of TiO2. However, the rare earth materials are scarcity and cost, and the synthesis process of UCNCs using the rare earth materials is complicated. In the present study, we have designed a new approach using a rare earth-free upconversion nanocrystal (REF-UCNCs) as upconversion luminescent material to replace the rare earth UCNCs. A novel nanocomposite photocatalyst of REF-UCNCs@P25: Mo/GN was developed for the first time. Based on the designed structure, the REF-UCNCs, Mo-doping, and GN (graphene) have a synergistic effect that can improve catalytic activity of P25 significantly. The results of photocatalytic experiments using RhB as a model pollutant under simulated solar light irradiation show that the photocatalytic efficiency of the as-prepared catalyst is 3-folds higher than that of benchmark substance P25. This work provides a new strategy for efficiently improving catalytic activity of semiconductor photocatalysts by coupling with REF-UCNCs. This approach is facile and low-cost which can be widely applied for modification of semiconductor photocatalysts and facilitates their applications in environmental protection issues using solar light.

Ln(3+)-doped nanoparticles for upconversion and magnetic resonance imaging: some critical notes on recent progress and some aspects to be considered.

PubMed

van Veggel, Frank C J M; Dong, Cunhai; Johnson, Noah J J; Pichaandi, Jothirmayanantham

2012-12-07

In this feature article we will critically discuss the synthesis and characterisation aspects of Ln(3+)-doped nanoparticles (NPs) that show upconversion, upon 980 nm excitation. Upconversion is a non-linear process that converts two or more low-energy photons, often near-infrared photons, into one of higher energy, e.g. blue and 800 nm from Tm(3+) and green and red from Er(3+) or Ho(3+). Nearly all researchers use the absorption of 980 nm light by Yb(3+) as the sensitiser for the co-doped emissive Ln(3+) ions. The focus will be on LnF(3) and MLnF(4) (M = alkali metal) as the host matrix, because most progress has been made with these. In particular we will argue that a detailed understanding of how the dopant ions and the host Ln(3+) ions are distributed (in the core) and how (doped) shell growth occurs is not well understood. Moreover, their use as optical and magnetic resonance imaging contrast agents will be discussed. We will argue that deep-tissue imaging beyond 600 μm with retention of optical resolution, i.e. to see fine structure such as blood capillaries in brain tissues, has not yet been achieved. Three key parameters have been identified as impediments: (i) the low absorption efficiency of the Yb(3+) sensitiser, (ii) the low quantum yield of upconversion, and (iii) the long-lived excited states. On the other hand, there are very encouraging results that suggest that these nanoparticles could be developed into very potent magnetic resonance imaging (MRI) contrast agents.

Ln3+-doped nanoparticles for upconversion and magnetic resonance imaging: some critical notes on recent progress and some aspects to be considered

NASA Astrophysics Data System (ADS)

van Veggel, Frank C. J. M.; Dong, Cunhai; Johnson, Noah J. J.; Pichaandi, Jothirmayanantham

2012-11-01

In this feature article we will critically discuss the synthesis and characterisation aspects of Ln3+-doped nanoparticles (NPs) that show upconversion, upon 980 nm excitation. Upconversion is a non-linear process that converts two or more low-energy photons, often near-infrared photons, into one of higher energy, e.g. blue and 800 nm from Tm3+ and green and red from Er3+ or Ho3+. Nearly all researchers use the absorption of 980 nm light by Yb3+ as the sensitiser for the co-doped emissive Ln3+ ions. The focus will be on LnF3 and MLnF4 (M = alkali metal) as the host matrix, because most progress has been made with these. In particular we will argue that a detailed understanding of how the dopant ions and the host Ln3+ ions are distributed (in the core) and how (doped) shell growth occurs is not well understood. Moreover, their use as optical and magnetic resonance imaging contrast agents will be discussed. We will argue that deep-tissue imaging beyond 600 μm with retention of optical resolution, i.e. to see fine structure such as blood capillaries in brain tissues, has not yet been achieved. Three key parameters have been identified as impediments: (i) the low absorption efficiency of the Yb3+ sensitiser, (ii) the low quantum yield of upconversion, and (iii) the long-lived excited states. On the other hand, there are very encouraging results that suggest that these nanoparticles could be developed into very potent magnetic resonance imaging (MRI) contrast agents.

Microwave assisted synthesis of luminescent carbonaceous nanoparticles from silk fibroin for bioimaging.

PubMed

Gao, Hongzhi; Teng, Choon Peng; Huang, Donghong; Xu, Wanqing; Zheng, Chaohui; Chen, Yisong; Liu, Minghuan; Yang, Da-Peng; Lin, Ming; Li, Zibiao; Ye, Enyi

2017-11-01

Bombyx mori silk as a natural protein based biopolymer with high nitrogen content, is abundant and sustainable because of its mass product all over the world per year. In this study, we developed a facile and fast microwave-assisted synthesis of luminescent carbonaceous nanoparticles using Bombyx mori silk fibroin and silk solution as the precursors. As a result, the obtained carbonaceous nanoparticles exhibit a photoluminescence quantum yield of ~20%, high stability, low cytotoxicity, high biocompatibility. Most importantly, we successfully demonstrated bioimaging using these luminescent carbonaceous nanoparticles with excitation dependent luminescence. In addition, the microwave-assisted hydrothermal method can be extended to convert other biomass into functional nanomaterials. Copyright © 2017 Elsevier B.V. All rights reserved.

Controllable red, green, blue (RGB) and bright white upconversion luminescence of Lu2O3:Yb3+/Er3+/Tm3+ nanocrystals through single laser excitation at 980 nm.

PubMed

Yang, Jun; Zhang, Cuimiao; Peng, Chong; Li, Chunxia; Wang, Lili; Chai, Ruitao; Lin, Jun

2009-01-01

Light fantastic! Lu(2)O(3):Yb(3+)/Er(3+)/Tm(3+) nanocrystals with controllable red, green, blue (RGB) and bright white upconversion luminescence by a single laser excitation of 980 nm have been successfully synthesized (see picture). Due to abundant UC PL colors, it can potentially be used as fluorophores in the field of color displays, back light, UC lasers, photonics, and biomedicine.Lu(2)O(3):Yb(3+)/Er(3+)/Tm(3+) nanocrystals have been successfully synthesized by a solvothermal process followed by a subsequent heat treatment at 800 degrees C. Powder X-ray diffraction, transmission electron microscopy, upconversion photoluminescence spectra, and kinetic decay were used to characterize the samples. Under single-wavelength diode laser excitation of 980 nm, the bright blue emissions of Lu(2)O(3):Yb(3+), Tm(3+) nanocrystals near 477 and 490 nm were observed due to the (1)G(4)-->(3)H(6) transition of Tm(3+). The bright green UC emissions of Lu(2)O(3):Er(3+) nanocrystals appeared near 540 and 565 nm were observed and assigned to the (2)H(11/2)-->(4)I(15/2) and (4)S(3/2)-->(4)I(15/2) transitions, respectively, of Er(3+). The ratio of the intensity of green luminescence to that of red luminescence decreases with an increase of concentration of Yb(3+) in Lu(2)O(3):Er(3+) nanocrystals. In sufficient quantities of Yb(3+) with resprct to Er(3+), the bright red UC emission of Lu(2)O(3):Yb(3+)/Er(3+) centered at 662 nm was predominant, due to the (4)F(9/2)-->(4)I(15/2) transition of Er(3+). Based on the generation of red, green, and blue emissions in the different doped Lu(2)O(3):RE(3+) nanocrystals, it is possible to produce the luminescence with a wide spectrum of colors, including white, by the appropriate doping of Yb(3+), Tm(3+), and Er(3+) in the present Lu(2)O(3) nanocrystals. Namely, Lu(2)O(3):3 %Yb(3+)/0.2 %Tm(3+)/0.4 %Er(3+) nanocrystals show suitable intensities of blue, green, and red (RGB) emission, resulting in the production of perfect and bright white light with CIE-x=0.3456 and CIE-y=0.3179, which is very close to the standard equal energy white light illuminate (x=0.33, y=0.33). Because of abundant luminescent colors from RGB to white in Lu(2)O(3):Yb(3+)/Er(3+)/Tm(3+) nanocrystals under 980 nm laser diode (LD) excitation, they can potentially be used as fluorophores in the field of color displays, back light, UC lasers, photonics, and biomedicine.

Three-dimensional quick response code based on inkjet printing of upconversion fluorescent nanoparticles for drug anti-counterfeiting.

PubMed

You, Minli; Lin, Min; Wang, Shurui; Wang, Xuemin; Zhang, Ge; Hong, Yuan; Dong, Yuqing; Jin, Guorui; Xu, Feng

2016-05-21

Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients. In this contribution, we developed a smart phone recognition based upconversion fluorescent three-dimensional (3D) quick response (QR) code for tracking and anti-counterfeiting of drugs. We firstly formulated three colored inks incorporating upconversion nanoparticles with RGB (i.e., red, green and blue) emission colors. Using a modified inkjet printer, we printed a series of colors by precisely regulating the overlap of these three inks. Meanwhile, we developed a multilayer printing and splitting technology, which significantly increases the information storage capacity per unit area. As an example, we directly printed the upconversion fluorescent 3D QR code on the surface of drug capsules. The 3D QR code consisted of three different color layers with each layer encoded by information of different aspects of the drug. A smart phone APP was designed to decode the multicolor 3D QR code, providing the authenticity and related information of drugs. The developed technology possesses merits in terms of low cost, ease of operation, high throughput and high information capacity, thus holds great potential for drug anti-counterfeiting.

Enhanced near-infrared to visible upconversion nanoparticles of Ho³⁺-Yb³⁺-F⁻ tri-doped TiO₂ and its application in dye-sensitized solar cells with 37% improvement in power conversion efficiency.

PubMed

Yu, Jia; Yang, Yulin; Fan, Ruiqing; Liu, Danqing; Wei, Liguo; Chen, Shuo; Li, Liang; Yang, Bin; Cao, Wenwu

2014-08-04

New near-infrared (NIR)-to-green upconversion nanoparticles of Ho(3+)-Yb(3+)-F(-) tridoped TiO2 (UC-F-TiO2) were designed and fabricated via the hydrosol-hydrothermal method. Under 980 nm NIR excitation, UC-F-TiO2 emit strong green upconversion fluorescence with three emission bands at 543, 644, and 751 nm and convert the NIR light in situ to the dye-sensitive visible light that could effectively reduce the distance between upconversion materials and sensitizers; thus, they minimize the loss of the converted light. Our results show that this UC-F-TiO2 offers excellent opportunities for the other types of solar cells applications, such as organic solar cells, c-Si solar cells, multijunction solar cells, and so on. When integrating the UC-F-TiO2 into dye-sensitized solar cells (DSSCs), superior total energy conversion efficiency was achieved. Under AM1.5G light, open-circuit voltage reached 0.77 ± 0.01 V, short-circuit current density reached 21.00 ± 0.69 mA cm(-2), which resulted in an impressive overall energy conversion efficiency of 9.91 ± 0.30%, a 37% enhancement compared to DSSCs with pristine TiO2 photoanode.

Comparative analysis of luminescent properties of germanate glass and double-clad optical fibers co-doped with Yb3+/Ho3+ ions

NASA Astrophysics Data System (ADS)

Pietrzycki, Marcin; Kochanowicz, Marcin; Romańczuk, Patryk; Żmojda, Jacek; Miluski, Piotr; Ragiń, Tomasz; Jeleń, Piotr; Sitarz, Maciej; Dorosz, Dominik

2016-09-01

The 2 μm and visible emission of low phonon (805 cm-1) germanate glasses and double - clad optical fiber co-doped with 0.7Yb2O3/(0.07-0.7)Ho2O3 ions have been investigated. Luminescence at 2 μm corresponding to Ho3+: 5I7 → 5I8 as well as upconversion luminescence in the visible spectral range corresponding to the Ho3+: 5S2(5F4)→5I8 (545 nm), and Ho3+: 5F5→5I8 (655 nm) transition, respectively were obtained. The optimization of the acceptor content and donor-acceptor ratio were conducted with the purpose of maximizing the luminescence intensity. The highest luminescence intensity in both spectral range was obtained in glass co-doped with 0.7Yb2O3/0.15 Ho2O3. Despite relatively small effective absorption coefficient of the optical fiber comparative analysis of luminescent properties of fabricated glasses (further core) and double - clad optical fiber showed significant contribution of reabsorption process of emitted ASE signal.

Luminescence of colloidal ZnO nanoparticles synthesized in alcohols and biological application of ZnO passivated by MgO.

PubMed

Sikora, Bożena; Fronc, Krzysztof; Kamińska, Izabela; Koper, Kamil; Stępień, Piotr; Elbaum, Danek

2013-05-15

This report presents the results of spectroscopic measurements of colloidal ZnO nanoparticles synthesized in various alcohols. Luminescence of colloidal ZnO was monitored under different reaction conditions to elucidate the mechanism of the visible emission. We performed the process in different alcohols, temperatures and reaction times for two different reactants: water and NaOH. Based on the presented and previously published results it is apparent that the luminescence of the nanoparticles is influenced by several competing phenomena: the formation of new nucleation centers, the growth of the nanoparticles and surface passivation. Superimposed on the above effects is a size dependent luminescence alteration resulting from the quantum confinement. The study contributes to our understanding of the origin of ZnO nanoparticles' green emission which is important in a rational design of fluorescent probes for nontoxic biological applications. The ZnO nanoparticles were coated with a magnesium oxide layer and introduced into a HeLa cancer cell.

Developing upconversion nanoparticle-based smart substrates for remote temperature sensing

NASA Astrophysics Data System (ADS)

Coker, Zachary; Marble, Kassie; Alkahtani, Masfer; Hemmer, Philip; Yakovlev, Vladislav V.

2018-02-01

Recent developments in understanding of nanomaterial behaviors and synthesis have led to their application across a wide range of commercial and scientific applications. Recent investigations span from applications in nanomedicine and the development of novel drug delivery systems to nanoelectronics and biosensors. In this study, we propose the application of a newly engineered temperature sensitive water-based bio-compatible core/shell up-conversion nanoparticle (UCNP) in the development of a smart substrate for remote temperature sensing. We developed this smart substrate by dispersing functionalized nanoparticles into a polymer solution and then spin-coating the solution onto one side of a microscope slide to form a thin film substrate layer of evenly dispersed nanoparticles. By using spin-coating to deposit the particle solution we both create a uniform surface for the substrate while simultaneously avoid undesired particle agglomeration. Through this investigation, we have determined the sensitivity and capabilities of this smart substrate and conclude that further development can lead to a greater range of applications for this type smart substrate and use in remote temperature sensing in conjunction with other microscopy and spectroscopy investigations.

Upconverting rare-earth nanoparticles with a paramagnetic lanthanide complex shell for upconversion fluorescent and magnetic resonance dual-modality imaging

NASA Astrophysics Data System (ADS)

Wang, Yan; Ji, Lei; Zhang, Bingbo; Yin, Peihao; Qiu, Yanyan; Song, Daqian; Zhou, Juying; Li, Qi

2013-05-01

Multi-modal imaging based on multifunctional nanoparticles is a promising alternative approach to improve the sensitivity of early cancer diagnosis. In this study, highly upconverting fluorescence and strong relaxivity rare-earth nanoparticles coated with paramagnetic lanthanide complex shells and polyethylene glycol (PEGylated UCNPs@DTPA-Gd3+) are synthesized as dual-modality imaging contrast agents (CAs) for upconverting fluorescent and magnetic resonance dual-modality imaging. PEGylated UCNPs@DTPA-Gd3+ with sizes in the range of 32-86 nm are colloidally stable. They exhibit higher longitudinal relaxivity and transverse relaxivity in water (r1 and r2 values are 7.4 and 27.8 s-1 per mM Gd3+, respectively) than does commercial Gd-DTPA (r1 and r2 values of 3.7 and 4.6 s-1 per mM Gd3+, respectively). They are found to be biocompatible. In vitro cancer cell imaging shows good imaging contrast of PEGylated UCNPs@DTPA-Gd3+. In vivo upconversion fluorescent imaging and T1-weighted MRI show excellent enhancement of both fluorescent and MR signals in the livers of mice administered PEGylated UCNPs@DTPA-Gd3+. All the experimental results indicate that the synthesized PEGylated UCNPs@DTPA-Gd3+ present great potential for biomedical upconversion of fluorescent and magnetic resonance dual-modality imaging applications.

Sub-10 nm Water-Dispersible β-NaGdF4:X% Eu3+ Nanoparticles with Enhanced Biocompatibility for in Vivo X-ray Luminescence Computed Tomography.

PubMed

Zhang, Wenli; Shen, Yingli; Liu, Miao; Gao, Peng; Pu, Huangsheng; Fan, Li; Jiang, Ruibin; Liu, Zonghuai; Shi, Feng; Lu, Hongbing

2017-11-22

As a novel molecular and functional imaging modality, X-ray luminescence computed tomography (XLCT) has shown its potentials in biomedical and preclinic applications. However, there are still some limitations of X-ray-excited luminescent materials, such as low luminescence efficiency, poor biocompatibility, and cytotoxicity, making in vivo XLCT imaging quite challenging. In this study, for the very first time, we present on using sub-10 nm β-NaGdF 4 :X% Eu 3+ nanoparticles with poly(acrylic acid) (PAA) surface modification, which demonstrate outstanding luminescence efficiency, uniform size distribution, water dispersity, and biosafety, as the luminescent probes for in vivo XLCT application. The pure hexagonal phase (β-) NaGdF 4 has been successfully synthesized and characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), and then the results of X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectrometry  (EDX), and elemental mapping further confirm Eu 3+ ions doped into NaGdF 4 host. Under X-ray excitation, the β-NaGdF 4 nanoparticles with a doping level of 15% Eu 3+ exhibited the most efficient luminescence intensity. Notably, the doping level of Eu 3+ has no effect on the crystal phase and morphology of the NaGdF 4 -based host. Afterward, β-NaGdF 4 :15% Eu 3+ nanoparticles were modified with PAA to enhance the water dispersity and biocompatibility. The compatibility of in vivo XLCT imaging using such nanoparticles was systematically studied via in vitro cytotoxicity, physical phantom, and in vivo imaging experiments. The ultralow cytotoxicity of PAA-modified nanoparticles, which is confirmed by over 80% cell viability of SH-SY5Y cells when treated by high nanoparticle concentration of 200 μg/mL, overcome the major obstacle for in vivo application. In addition, the high luminescence intensity of PAA-modified nanoparticles enables the location error of in vivo XLCT imaging less than 2 mm, which is comparable to that using commercially available bulk material Y 2 O 3 :15% Eu 3+ . The proposed nanoparticles promote XLCT research into an in vivo stage. Further modification of these nanoparticles with biofunctional molecules could enable the potential of targeting XLCT imaging.

Dental optical tomography with upconversion nanoparticles—a feasibility study

PubMed Central

Long, Feixiao; Intes, Xavier

2017-01-01

Abstract. Upconversion nanoparticles (UCNPs) have the unique ability to emit multiple colors upon excitation by near-infrared (NIR) light. Herein, we investigate the potential use of UCNPs as contrast agents for dental optical tomography, with a focus on monitoring the status of fillings after dental restoration. The potential of performing tomographic imaging using UCNP emission of visible or NIR light is established. This in silico and ex vivo study paves the way toward employing UCNPs as theranostic agents for dental applications. PMID:28586852

Dental optical tomography with upconversion nanoparticles—a feasibility study

NASA Astrophysics Data System (ADS)

Long, Feixiao; Intes, Xavier

2017-06-01

Upconversion nanoparticles (UCNPs) have the unique ability to emit multiple colors upon excitation by near-infrared (NIR) light. Herein, we investigate the potential use of UCNPs as contrast agents for dental optical tomography, with a focus on monitoring the status of fillings after dental restoration. The potential of performing tomographic imaging using UCNP emission of visible or NIR light is established. This in silico and ex vivo study paves the way toward employing UCNPs as theranostic agents for dental applications.

Multicolor upconversion emission from Tm3++Ho3++Yb3+ codoped tellurite glass on NIR excitations

NASA Astrophysics Data System (ADS)

Giri, N. K.; Rai, D. K.; Rai, S. B.

2008-06-01

Multicolor emission has been produced using 798 nm and 980 nm laser excitation in a Tm3++Ho3++Yb3+ codoped tellurite based glass. This glass generates simultaneously red, green and blue (RGB) emission on 798 nm excitation. Multicolor emission thus obtained was tuned to white luminescence by adjusting the Ho3+ ion concentration. There is a close match between the calculated color coordinate for the white luminescence obtained here and the point of equal energy which represents white in the 1931 CIE chromaticity diagram. The 980 nm excitation of the same sample on the other hand gives intense green and red emission and the glass appears greenish.

Up-conversion multiwave (White) luminescence in the visible spectral range under excitation by IR laser diodes in the active BaY2F8:Yb3+,Pr3+ medium

NASA Astrophysics Data System (ADS)

Pushkar', A. A.; Uvarova, T. V.; Kiiko, V. V.

2011-08-01

The possibilities of occupying high-lying 4 f states of Pr3+ ions in the active BaY2F8:Yb3+,Pr3+ medium according to the photon avalanche and step-by-step sensitization mechanisms are compared. It is shown that the photon avalanche is unlikely to occur in the BaY2F8:Yb3+,Pr3+ crystal. The multiband luminescence spectra in the visible spectral range (white emission) under single- and multiwave pumping of BaY2F8:Yb3+,Pr3+ crystal by IR laser diodes are reported.

All-inorganic colloidal upconversion quantum dots (Conference Presentation)

NASA Astrophysics Data System (ADS)

Oron, Dan; Teitelboim, Ayelet

2017-02-01

Upconversion (UC) is a nonlinear process in which two, or more, long wavelength photons are converted to a shorter wavelength photon. This process is based on sequential absorption of two or more photons, involving metastable, long lived intermediate energy states, thus is not restricted to ultrashort pulsed excitation. Hence, requirements for UC processes are long lived excited states, a ladder like arrangement of energy levels and a mechanism inhibiting cooling of the hot charge carrier. UC holds great promise for bioimaging, enabling to perform multiphoton imaging in scattering specimen at very low powers. Rare-earth-doped nanocrystals, the most commonly used ones for UC, typically require a minimal particle diameter of several tens of nanometers and have a limited action spectrum. Here, we present a novel luminescence upconversion nano-system based on colloidal semiconductor double quantum dots, consisting of a NIR-absorbing component and a visible emitting component separated by a tunneling barrier in a spherical onion-like geometry. These dual near-infrared and visible core/shell/shell PbSe/CdSe/CdS nanocrystals are shown to efficiently upconvert a broad range of NIR wavelengths up to 1.2 microns to visible emission at room temperature, covering a spectral range where there are practically no alternative upconversion systems. The particle diameter is less than ten nanometers, and the synthesis enables versatility and tunability of both the visible emission color and the NIR absorption edge. The physical mechanism for upconversion in this type of structures, as well as potential advances and extensions on this system will be discussed.

Decorating fiber nanotip with single perovskite quantum dot and other luminescent nanocrystals synthesized in oil-phase

NASA Astrophysics Data System (ADS)

Qian, Yu; Xing, Xing; Xu, Ya; Lu, Zhenda; Zhang, Weihua

2017-11-01

We report a simple yet robust method for fabricating single perovskite quantum dot (QD) decorated fiber nanotips. In this method, a single QD is directly picked up and subsequently glued on the apex of a specially fabricated cantilever fiber tip with a high success rate (approx. 70%) without using expensive close-loop feedback systems. Thanks to the flexibility and robustness of the fiber tips, no damage of the tips was observed in the process. Moreover, nanocrystal (NC) dispersing technique was developed to avoid undesired aggregations of QDs, and it guarantees that only one QD is glued each time. Finally, we demonstrate that this technique can also be applied to other oil-phase synthesized NCs, including CdSe QDs and upconversion luminescent NCs. It leads to many important applications on probing the local environment using high performance luminescent nanoprobes.

Reversible near-infrared light directed reflection in a self-organized helical superstructure loaded with upconversion nanoparticles.

PubMed

Wang, Ling; Dong, Hao; Li, Yannian; Xue, Chenming; Sun, Ling-Dong; Yan, Chun-Hua; Li, Quan

2014-03-26

Adding external, dynamic control to self-organized superstructures with desired functionalities is an important leap necessary in leveraging the fascinating molecular systems for applications. Here, the new light-driven chiral molecular switch and upconversion nanoparticles, doped in a liquid crystal media, were able to self-organize into an optically tunable helical superstructure. The resulting nanoparticle impregnated helical superstructure was found to exhibit unprecedented reversible near-infrared (NIR) light-guided tunable behavior only by modulating the excitation power density of a continuous-wave NIR laser (980 nm). Upon irradiation by the NIR laser at the high power density, the reflection wavelength of the photonic superstructure red-shifted, whereas its reverse process occurred upon irradiation by the same laser but with the lower power density. Furthermore, reversible dynamic NIR-light-driven red, green, and blue reflections in a single thin film, achieved only by varying the power density of the NIR light, were for the first time demonstrated.

Nanoscale “fluorescent stone”: Luminescent Calcium Fluoride Nanoparticles as Theranostic Platforms

PubMed Central

Li, Zhanjun; Zhang, Yuanwei; Huang, Ling; Yang, Yuchen; Zhao, Yang; El-Banna, Ghida; Han, Gang

2016-01-01

Calcium Fluoride (CaF2) based luminescent nanoparticles exhibit unique, outstanding luminescent properties, and represent promising candidates as nanoplatforms for theranostic applications. There is an urgent need to facilitate their further development and applications in diagnostics and therapeutics as a novel class of nanotools. Here, in this critical review, we outlined the recent significant progresses made in CaF2-related nanoparticles: Firstly, their physical chemical properties, synthesis chemistry, and nanostructure fabrication are summarized. Secondly, their applications in deep tissue bio-detection, drug delivery, imaging, cell labeling, and therapy are reviewed. The exploration of CaF2-based luminescent nanoparticles as multifunctional nanoscale carriers for imaging-guided therapy is also presented. Finally, we discuss the challenges and opportunities in the development of such CaF2-based platform for future development in regard to its theranostic applications. PMID:27877242

Up-conversion luminescence coupled to plasmonic gold nanorods for light harvesting and hydrogen production.

PubMed

AlGhamdi, H; Katsiev, K; Wahab, A K; Llorca, J; Idriss, H

2017-12-05

The conversion of infrared light to visible-light which allows a larger fraction of sun-light to be used is needed to improve light-harvesting. In this work a tri-functional material composed of an up-converter (NaYF 4 -Yb-Tm), plasmonic gold nanorods and CdS was made photocatalytically active using 980 nm wavelength light for the reduction of H + to H 2 .

Local symmetric distortion boosted photon up-conversion and thermometric sensitivity in lanthanum oxide nanospheres.

PubMed

Suo, Hao; Zhao, Xiaoqi; Zhang, Zhiyu; Shi, Rui; Wu, Yanfang; Xiang, Jinmeng; Guo, Chongfeng

2018-05-17

It is essential to simultaneously boost the luminescence intensity and thermometric sensitivity of up-converted optical thermometers towards potential biomedical sensing applications. Herein, the effects of local site symmetry on the up-conversion (UC) emission and thermal sensing ability in trigonal-phased La2O3:Er3+/Yb3+ nanospheres were qualitatively explored using cubic-phased Lu2O3 and Y2O3 with a similar shape and phonon energy as contrasts. Under 980 nm light excitation, much stronger UC emissions were detected in La2O3 samples than that in cubic Lu2O3 and Y2O3 samples, and the possible mechanisms were elaborately proposed using Eu3+ as a luminescent probe. Thermo-responsive emission intensity from 2H11/2/4S3/2 levels was monitored to evaluate the absolute sensitivity of three samples, which strongly depends on the dopant-induced local site symmetric distortions according to the Judd-Ofelt theory. The potentiality of La2O3:Er3+/Yb3+ for sub-tissue thermometry was also validated by ex vivo experiments. Results open a promising avenue for realizing highly sensitive thermometry with a large signal-to-noise ratio in sub-tissues via finely tailoring the local site symmetry.

White light upconversion emissions in Er3+/Tm3+/Yb3+ tridoped oxyfluoride glass

NASA Astrophysics Data System (ADS)

Guan, Xiaoping; Xu, Wei; Zhu, Shuang; Song, Qiutong; Wu, Xijun; Liu, Hailong

2015-10-01

Rare earth ions doped glasses producing visible upconversion emissions are of great interest due to their potential applications in the photonics filed. In fact, practical application of upconversion emissions has been used to obtain color image displays and white light sources. However, there are few reports on the thermal effect on tuning the emission color of the RE doped materials. In this work, the Er3+/Tm3+/Yb3+ tridoped oxyfluoride glasses were prepared through high temperature solid-state method. Under a 980 nm diode laser excitation, the upconversion emissions from the samples were studied. At room-temperature, bright white luminescence, whose CIE chromaticity coordinate was about (0.28, 0.31), can be obtained when the excitation power was 120 mW. The emission color was changed by varying the intensity ratios between RGB bands, which are strongly dependent on the rare earth ions concentration. The temperature dependent color emissions were also investigated. As temperature increased, the intensities for the emission bands presented different decay rates, finally resulting in the changing of the CIE coordinate. When the temperature was 573 K, white light with color coordinate of (0.31, 0.33) was achieved, which matches well with the white reference (0.33, 0.33). The color tunability, high quality of white light and intense emission intensity make the transparent oxyfluoride glasses excellent candidates for applications in solid-state lighting.

Multi-photon excited luminescence of magnetic FePt core-shell nanoparticles.

PubMed

Seemann, K M; Kuhn, B

2014-07-01

We present magnetic FePt nanoparticles with a hydrophilic, inert, and biocompatible silico-tungsten oxide shell. The particles can be functionalized, optically detected, and optically manipulated. To show the functionalization the fluorescent dye NOPS was bound to the FePt core-shell nanoparticles with propyl-triethoxy-silane linkers and fluorescence of the labeled particles were observed in ethanol (EtOH). In aqueous dispersion the NOPS fluorescence is quenched making them invisible using 1-photon excitation. However, we observe bright luminescence of labeled and even unlabeled magnetic core-shell nanoparticles with multi-photon excitation. Luminescence can be detected in the near ultraviolet and the full visible spectral range by near infrared multi-photon excitation. For optical manipulation, we were able to drag clusters of particles, and maybe also single particles, by a focused laser beam that acts as optical tweezers by inducing an electric dipole in the insulated metal nanoparticles. In a first application, we show that the luminescence of the core-shell nanoparticles is bright enough for in vivo multi-photon imaging in the mouse neocortex down to cortical layer 5.

Near-infrared (NIR) optogenetics using up-conversion system

NASA Astrophysics Data System (ADS)

Hososhima, Shoko; Yuasa, Hideya; Ishizuka, Toru; Yawo, Hiromu

2015-03-01

Non-invasive remote control technologies designed to manipulate neural functions for a comprehensive and quantitative understanding of the neuronal network in the brain as well as for the therapy of neurological disorders have long been awaited. Recently, it has become possible to optically manipulate the neuronal activity using biological photo-reactive molecules such as channelrhodopsin-2 (ChR2). However, ChR2 and its relatives are mostly reactive to visible light which does not effectively penetrate through biological tissues. In contrast, near-infrared (NIR) light penetrates deep into the tissues because biological systems are almost transparent to light within this so-called `imaging window'. Here we used lanthanide nanoparticles (LNPs), which are composed of rare-earth elements, as luminous bodies to activate channelrhodopsins (ChRs) since they absorb low-energy NIR light to emit high-energy visible light (up-conversion). Neuron-glioma-hybrid ND-7/23 cells were cultured with LNP(NaYF4:Sc/Yb/Er) particles (peak emission, 543 nm) and transfected to express C1V1 (peak absorbance, 539 nm), a chimera of ChR1 and VChR1. The photocurrents were generated in response to NIR laser light (976 nm) to a level comparable to that evoked by a filtered Hg lamp (530-550 nm). NIR light pulses also evoked action potentials in the cultured neurons that expressed C1V1. It is suggested that the green luminescent light emitted from LNPs effectively activated C1V1 to generate the photocurrent. With the optimization of LNPs, acceptor photo-reactive biomolecules and optics, this system could be applied to non-invasively actuate neurons deep in the brain.

In-situ laser-induced synthesis of associated YVO4:Eu3+@SiO2@Au-Ag/C nanohybrids with enhanced luminescence

NASA Astrophysics Data System (ADS)

Kolesnikov, I. E.; lvanova, T. Yu.; Ivanov, D. A.; Kireev, A. A.; Mamonova, D. V.; Golyeva, E. V.; Mikhailov, M. D.; Manshina, A. A.

2018-02-01

Associated luminescence/plasmonic nanoparticles were prepared in a single step process as a result of laser illumination (low intensity CW He-Cd laser) of colloidal solution of YVO4:Eu3+@SiO2 mixed with heterometallic supramolecular complex. The results of SEM-EDX analysis, absorption, steady-state luminescence and luminescence decay measurements revealed formation of associated nanohybrids with core/shell morphology. The obtained nanostructures demonstrated metal enhanced luminescence with enhancement factor of 1.6. The theoretical calculations revealed strong correlation of enhancement factor and plasmonic nanoparticles number.

Bioinspired near-infrared-excited sensing platform for in vitro antioxidant capacity assay based on upconversion nanoparticles and a dopamine-melanin hybrid system.

PubMed

Wang, Dong; Chen, Chuan; Ke, Xuebin; Kang, Ning; Shen, Yuqing; Liu, Yongliang; Zhou, Xi; Wang, Hongjun; Chen, Changqing; Ren, Lei

2015-02-11

A novel core-shell structure based on upconversion fluorescent nanoparticles (UCNPs) and dopamine-melanin has been developed for evaluation of the antioxidant capacity of biological fluids. In this approach, dopamine-melanin nanoshells facilely formed on the surface of UCNPs act as ultraefficient quenchers for upconversion fluorescence, contributing to a photoinduced electron-transfer mechanism. This spontaneous oxidative polymerization of the dopamine-induced quenching effect could be effectively prevented by the presence of various antioxidants (typically biothiols, ascorbic acid (Vitamin C), and Trolox). The chemical response of the UCNPs@dopamine-melanin hybrid system exhibited great selectivity and sensitivity toward antioxidants relative to other compounds at 100-fold higher concentration. A satisfactory correlation was established between the ratio of the "anti-quenching" fluorescence intensity and the concentration of antioxidants. Besides the response of the upconversion fluorescence signal, a specific evaluation process for antioxidants could be visualized by the color change from colorless to dark gray accompanied by the spontaneous oxidation of dopamine. The near-infrared (NIR)-excited UCNP-based antioxidant capacity assay platform was further used to evaluate the antioxidant capacity of cell extracts and human plasma, and satisfactory sensitivity, repeatability, and recovery rate were obtained. This approach features easy preparation, fluorescence/visual dual mode detection, high specificity to antioxidants, and enhanced sensitivity with NIR excitation, showing great potential for screening and quantitative evaluation of antioxidants in biological systems.

Luminescence of colloidal ZnO nanoparticles synthesized in alcohols and biological application of ZnO passivated by MgO

NASA Astrophysics Data System (ADS)

Sikora, Bożena; Fronc, Krzysztof; Kamińska, Izabela; Koper, Kamil; Stępień, Piotr; Elbaum, Danek

2013-05-01

This report presents the results of spectroscopic measurements of colloidal ZnO nanoparticles synthesized in various alcohols. Luminescence of colloidal ZnO was monitored under different reaction conditions to elucidate the mechanism of the visible emission. We performed the process in different alcohols, temperatures and reaction times for two different reactants: water and NaOH. Based on the presented and previously published results it is apparent that the luminescence of the nanoparticles is influenced by several competing phenomena: the formation of new nucleation centers, the growth of the nanoparticles and surface passivation. Superimposed on the above effects is a size dependent luminescence alteration resulting from the quantum confinement. The study contributes to our understanding of the origin of ZnO nanoparticles’ green emission which is important in a rational design of fluorescent probes for nontoxic biological applications. The ZnO nanoparticles were coated with a magnesium oxide layer and introduced into a HeLa cancer cell.

High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

PubMed Central

Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

2017-01-01

Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging. PMID:28091590

High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

NASA Astrophysics Data System (ADS)

Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

2017-01-01

Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging.

Tailoring Plasmonic Enhanced Upconversion in Single NaYF4:Yb3+/Er3+ Nanocrystals

NASA Astrophysics Data System (ADS)

Wang, Ya-Lan; Mohammadi Estakhri, Nasim; Johnson, Amber; Li, Hai-Yang; Xu, Li-Xiang; Zhang, Zhenyu; Alù, Andrea; Wang, Qu-Quan; Shih, Chih-Kang (Ken)

2015-05-01

By using silver nanoplatelets with a widely tunable localized surface plasmon resonance (LSPR), and their corresponding local field enhancement, here we show large manipulation of plasmonic enhanced upconversion in NaYF4:Yb3+/Er3+ nanocrystals at the single particle level. In particular, we show that when the plasmonic resonance of silver nanolplatelets is tuned to 656 nm, matching the emission wavelength, an upconversion enhancement factor ~5 is obtained. However, when the plasmonic resonance is tuned to 980 nm, matching the nanocrystal absorption wavelength, we achieve an enhancement factor of ~22 folds. The precise geometric arrangement between fluorescent nanoparticles and silver nanoplatelets allows us to make, for the first time, a comparative analysis between experimental results and numerical simulations, yielding a quantitative agreement at the single particle level. Such a comparison lays the foundations for a rational design of hybrid metal-fluorescent nanocrystals to harness the upconversion enhancement for biosensing and light harvesting applications.

One-step synthesis of NaLu80-xGdxF4:Yb183+/Er23+(Tm3+) upconversion nanoparticles for in vitro cell imaging.

PubMed

Gerelkhuu, Zayakhuu; Huy, Bui The; Sharipov, Mirkomil; Jung, Dasom; Phan, The-Long; Conte, Eric D; Lee, Yong-Ill

2018-05-01

Upconversion nanoparticles (UCNPs) possess a unique type of photoluminescence (PL) in which lower-energy excitation is converted into higher-energy emission via multi-photon absorption processes. In this work, we have used a facile one-step hydrothermal method promoted water solubility to synthesis NaLuGdF 4 :Yb 3+ /Er 3+ (Tm 3+ ) UCNPs coated with malonic acid (MA). Scanning electron microscopy images and X-ray diffraction patterns reveal sphere-shaped UCNPs with an average size of ~80nm crystallized in the cubic NaLuF 4 structure. The characteristic vibrations of cubic UCNPs have been taken into account by using Fourier-transform infrared spectroscopy. Based on PL studies, we have determined an optimal concentration of Gd 3+ doping. The dependence of upconversion PL intensity on Gd 3+ concentration is discussed via the results of magnetization measurements, which is related to the coupling/uncoupling of Gd 3+ ions. Particularly, our study reveals that carboxyl-functionalized NaLuGdF 4 :Yb 3+ /Er 3+ (Tm 3+ ) UCNPs have a relatively high cell viability with HeLa cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Luminescence of Er 3+-doped nanostructured SiO 2-LaF 3 glass-ceramics prepared by the sol-gel method

NASA Astrophysics Data System (ADS)

Rodríguez, V. D.; Del Castillo, J.; Yanes, A. C.; Méndez-Ramos, J.; Torres, M.; Peraza, J.

2007-07-01

Transparent glass ceramics with composition of 95SiO2-5LaF3 doped with 0.1 mol% of Er3+ were synthesized by thermal treatment of precursor sol-gel glasses. Segregated LaF3 nanocrystals in the glass were confirmed from a structural analysis performed by X-ray diffraction. Blue, green and red efficient up-conversion emissions were observed under 980 nm excitation at room temperature. Under this excitation near infrared down-conversion at 1.55 μm is also observed. These results could be attributed to the precipitation of LaF3 nanocrystals and the incorporation of most Er3+ ions in these nanocrystals. The mechanisms involved in the up-conversion emissions could be ascribed to two and three photon processes.

Bright Photon Upconversion on Composite Organic Lanthanide Molecules through Localized Thermal Radiation.

PubMed

Ye, Huanqing; Bogdanov, Viktor; Liu, Sheng; Vajandar, Saumitra; Osipowicz, Thomas; Hernández, Ignacio; Xiong, Qihua

2017-12-07

Converting low-energy photons via thermal radiation can be a potential approach for utilizing infrared (IR) photons to improve photovoltaic efficiency. Lanthanide-containing materials have achieved great progress in IR-to-visible photon upconversion (UC). Herein, we first report bright photon, tunable wavelength UC through localized thermal radiation at the molecular scale with low excitation power density (<10 W/cm 2 ) realized on lanthanide complexes of perfluorinated organic ligands. This is enabled by engineering the pathways of nonradiative de-excitation and energy transfer in a composite of ytterbium and terbium perfluoroimidodiphosphinates. The IR-excited thermal UC and wavelength control is realized through the terbium activators sensitized by the ytterbium sensitizers having high luminescence efficiency. The metallic molecular composite thus can be a potential energy material in the use of the IR solar spectrum for thermal photovoltaic applications.

Electro-holographic display using a ZBLAN glass as the image space.

PubMed

Son, Jung-Young; Lee, Hyoung; Byeon, Jina; Zhao, Jiangbo; Ebendorff-Heidepriem, Heike

2017-04-01

An Er³⁺-doped ZBLAN glass is used to display a 360° viewable reconstructed image from a hologram on a DMD. The reconstructed image, when the hologram is illuminated by a 852 nm wavelength laser beam, is situated at the inside of the glass, and then a 1530 nm wavelength laser beam is crossed through the image to light it with an upconversion green light, which is viewable at all surrounding directions. This enables us to eliminate the limitation of the viewing zone angle imposed by the finite size of pixels in electro-holographic displays based on digital display chips/panels. The amount of the green light is much higher than that known previously. This is partly caused by the upconversion luminescence induced by 852 and 1530 nm laser beams.

Arsenic detection in water: YPO{sub 4}:Eu{sup 3+} nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Debasish; Luwang, Meitram Niraj, E-mail: mn.luwang@ncl.res.in; Academy of Scientific and Innovative Research

This work reports on the novel technique of detection of arsenic in aqueous solution utilising the luminescence properties of lanthanide doped nanomaterials. Eu{sup 3+} (5%) doped YPO{sub 4}nanorodswere utilised for the said experiment. Co-precipitation method was used for the synthesis of the materials and characterised them with different instrumental techniques like X-ray diffraction (XRD), Infra-red (IR), UV-absorption, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence studies. This nanoparticle can adsorb both arsenic and arsenious acids. We studied the effect of arsenic adsorption on the luminescence behaviour of the nanoparticles. Arsenic acid enhanced the luminescencemore » intensity whereas arsenious acid quenched the luminescence. This luminescence enhancement or quenching is related with arsenic concentration. This relation of luminescence property with concentration of arsenic can be used to detect arsenic in industrial waste. - Graphical abstract: Novel technique of detection of Arsenic ion in aqueous solution utilising the luminescence properties of lanthanide doped nanomaterials. Potential application for detection of arsenic in drinking and industrial waste water. - Highlights: • Novel technique of detection of Arsenic in aqueous solution by YPO{sub 4}:Eu{sup 3+} nanomaterials. • The effect of arsenic adsorption on the luminescence behaviour of the nanoparticles was studied. • Arsenic acid enhance whereas arsenious acid quenches the luminescence intensity. • This technique can be used to detect arsenic in industrial waste.« less

Luminescence properties of femtosecond-laser-activated silver oxide nanoparticles embedded in a biopolymer matrix

NASA Astrophysics Data System (ADS)

Gleitsmann, T.; Bernhardt, T. M.; Wöste, L.

2006-01-01

Strong visible luminescence is observed from silver clusters generated by femtosecond-laser-induced reduction of silver oxide nanoparticles embedded in a polymeric gelatin matrix. Light emission from the femtosecond-laser-activated matrix areas considerably exceeds the luminescence intensity of similarly activated bare silver oxide nanoparticle films. Optical spectroscopy of the activated polymer films supports the assignment of the emissive properties to the formation of small silver clusters under focused femtosecond-laser irradiation. The size of the photogenerated clusters is found to sensitively depend on the laser exposure time, eventually leading to the formation of areas of metallic silver in the biopolymer matrix. In this case, luminescence can still be observed in the periphery of the metallic silver structures, emphasizing the importance of the organic matrix for the stabilization of the luminescent nanocluster structures at the metal matrix interface.

Recent Advances on Inorganic Nanoparticle-Based Cancer Therapeutic Agents

PubMed Central

Wang, Fenglin; Li, Chengyao; Cheng, Jing; Yuan, Zhiqin

2016-01-01

Inorganic nanoparticles have been widely investigated as therapeutic agents for cancer treatments in biomedical fields due to their unique physical/chemical properties, versatile synthetic strategies, easy surface functionalization and excellent biocompatibility. This review focuses on the discussion of several types of inorganic nanoparticle-based cancer therapeutic agents, including gold nanoparticles, magnetic nanoparticles, upconversion nanoparticles and mesoporous silica nanoparticles. Several cancer therapy techniques are briefly introduced at the beginning. Emphasis is placed on how these inorganic nanoparticles can provide enhanced therapeutic efficacy in cancer treatment through site-specific accumulation, targeted drug delivery and stimulated drug release, with elaborations on several examples to highlight the respective strategies adopted. Finally, a brief summary and future challenges are included. PMID:27898016

Recent Advances on Inorganic Nanoparticle-Based Cancer Therapeutic Agents.

PubMed

Wang, Fenglin; Li, Chengyao; Cheng, Jing; Yuan, Zhiqin

2016-11-25

Inorganic nanoparticles have been widely investigated as therapeutic agents for cancer treatments in biomedical fields due to their unique physical/chemical properties, versatile synthetic strategies, easy surface functionalization and excellent biocompatibility. This review focuses on the discussion of several types of inorganic nanoparticle-based cancer therapeutic agents, including gold nanoparticles, magnetic nanoparticles, upconversion nanoparticles and mesoporous silica nanoparticles. Several cancer therapy techniques are briefly introduced at the beginning. Emphasis is placed on how these inorganic nanoparticles can provide enhanced therapeutic efficacy in cancer treatment through site-specific accumulation, targeted drug delivery and stimulated drug release, with elaborations on several examples to highlight the respective strategies adopted. Finally, a brief summary and future challenges are included.

Enhancement of anti-stokes sensitized luminescence in AgCl(I) crystals in the presence of silver nanoparticles

NASA Astrophysics Data System (ADS)

Chung, Nguyen Thi Kim; Egorushina, E. A.; Latyshev, A. N.; Ovchinnikov, O. V.; Smirnov, M. S.; Suvorova, T. I.

2012-01-01

We have observed a significant increase in the intensity with anti-Stokes excitation of recombination luminescence in AgCl(I) microcrystals sensitized by methylene blue molecules in the presence of silver nanoparticles.

Thermometry properties of Er, Yb-Gd2O2S microparticles: dependence on the excitation mode (cw versus pulsed excitation) and excitation wavelength (980 nm versus 1500 nm)

NASA Astrophysics Data System (ADS)

Avram, Daniel; Tiseanu, Carmen

2018-04-01

Herein, we present a first report on the luminescence thermometry properties of Er, Yb doped Gd2O2S microparticles under near infrared up-conversion excitation at 980 and 1500 nm measured in the 280-800 K interval. The thermometry properties are assessed using both cw and ns pulsed excitation as well as tuning the excitation wavelength across Yb and Er absorption profiles. For low cw (300 mW cm-1) and pulsed ns (400 ÷ 550 mW cm-1) excitation modes, no thermal load is observed. At room-temperature (280 K), the maximum relative sensitivity values are comparable under pulsed excitation at 980 and 1500 nm, around ˜0.01 and ˜0.008% K-1, respectively. In addition, a relative intense up-conversion emission at 980 nm under excitation at 1500 nm is measured. Our findings evidence attractive up-conversion and thermometry properties Er, Yb doped Gd2O2S under near-infrared excitation and highlight the need to explore further these properties in the nanoparticulate regime.

Upconversion luminescence of Er3+/Yb3+ doped Sr5(PO4)3OH phosphor powders

NASA Astrophysics Data System (ADS)

Mokoena, P. P.; Swart, H. C.; Ntwaeaborwa, O. M.

2018-04-01

Sr5(PO4)3OH co-doped with Er3+and Yb3+ powder phosphors were synthesized by urea combustion method. The crystal structure was analyzed using X-ray diffraction (XRD). Particle morphology was analyzed using a Jeol JSM 7800F thermal field emission scanning electron microscope (FE-SEM) and the chemical composition analysis was carried out using an Oxford Instruments AzTEC energy dispersive spectrometer (EDS) attached to the FE-SEM. Upconversion emission was measured by using a FLS980 Spectrometer equipped with a 980 nm NIR laser as the excitation source, and a photomultiplier (PMT) detector. The XRD data of the Sr5(PO4)3OH powder exhibited characteristic diffraction patterns of the hexagonal structure referenced in the standard JCPDS card number 00-033-1348. The sharp peaks revealed the formation of crystalline Sr5(PO4)3OH. The powders were made up of hexagonal nanospheres. The enhanced red emission due to the 4F9/2 → 4I15/2 transitions of Er3+ was observed and was attributed to up conversion (UC) energy transfer from Yb3+. The upconversion energy transfer mechanism from Yb3+ to Er3+ is discussed.

Size-dependent abnormal thermo-enhanced luminescence of ytterbium-doped nanoparticles.

PubMed

Cui, Xiangshui; Cheng, Yao; Lin, Hang; Huang, Feng; Wu, Qingping; Wang, Yuansheng

2017-09-21

Thermal quenching above 300 K is widely expected in photoluminescence. Luminescence quenching is usually ascribed to the non-radiative relaxation of excited electrons to the ground state of the activators, during which a high temperature always plays a role in pushing the excited electrons towards the quenching channels, leading to thermal quenching. For the lanthanide-doped nanoparticles, however, there is a special luminescence quenching channel that does not exist in their bulk counterparts, i.e., energy migration-induced surface quenching. Herein, a size-dependent abnormal thermal enhancement of luminescence in the temperature range of 300 K to 423 K in the ytterbium-doped fluoride nanoparticles is presented for the first time. Importantly, in this work, we originally demonstrate that the energy migration-induced surface quenching can be suppressed by increasing temperature, which results in the abnormal thermal enhancement of luminescence. According to the temperature-dependent X-ray diffraction and lifetime analyses, an underlying mechanism based on the effect of thermal lattice expansion on ytterbium-mediated energy migration is proposed. This new finding adds new insights to the size effect on the luminescent characteristics of nanoparticles, which could be utilized to construct some unique nanostructures, especially for many important temperature-related purposes, such as thermal sensing technology.

Three-dimensional quick response code based on inkjet printing of upconversion fluorescent nanoparticles for drug anti-counterfeiting

NASA Astrophysics Data System (ADS)

You, Minli; Lin, Min; Wang, Shurui; Wang, Xuemin; Zhang, Ge; Hong, Yuan; Dong, Yuqing; Jin, Guorui; Xu, Feng

2016-05-01

Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients. In this contribution, we developed a smart phone recognition based upconversion fluorescent three-dimensional (3D) quick response (QR) code for tracking and anti-counterfeiting of drugs. We firstly formulated three colored inks incorporating upconversion nanoparticles with RGB (i.e., red, green and blue) emission colors. Using a modified inkjet printer, we printed a series of colors by precisely regulating the overlap of these three inks. Meanwhile, we developed a multilayer printing and splitting technology, which significantly increases the information storage capacity per unit area. As an example, we directly printed the upconversion fluorescent 3D QR code on the surface of drug capsules. The 3D QR code consisted of three different color layers with each layer encoded by information of different aspects of the drug. A smart phone APP was designed to decode the multicolor 3D QR code, providing the authenticity and related information of drugs. The developed technology possesses merits in terms of low cost, ease of operation, high throughput and high information capacity, thus holds great potential for drug anti-counterfeiting.Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients. In this contribution, we developed a smart phone recognition based upconversion fluorescent three-dimensional (3D) quick response (QR) code for tracking and anti-counterfeiting of drugs. We firstly formulated three colored inks incorporating upconversion nanoparticles with RGB (i.e., red, green and blue) emission colors. Using a modified inkjet printer, we printed a series of colors by precisely regulating the overlap of these three inks. Meanwhile, we developed a multilayer printing and splitting technology, which significantly increases the information storage capacity per unit area. As an example, we directly printed the upconversion fluorescent 3D QR code on the surface of drug capsules. The 3D QR code consisted of three different color layers with each layer encoded by information of different aspects of the drug. A smart phone APP was designed to decode the multicolor 3D QR code, providing the authenticity and related information of drugs. The developed technology possesses merits in terms of low cost, ease of operation, high throughput and high information capacity, thus holds great potential for drug anti-counterfeiting. Electronic supplementary information (ESI) available: Calculating details of UCNP content per 3D QR code and decoding process of the 3D QR code. See DOI: 10.1039/c6nr01353h

Fabrication of luminescent CdS nanoparticles on short-peptide-based hydrogel nanofibers: tuning of optoelectronic properties.

PubMed

Palui, Goutam; Nanda, Jayanta; Ray, Sudipta; Banerjee, Arindam

2009-07-13

The pH-induced self-assembly of three synthetic tripeptides in water medium is used to immobilize luminescent CdS nanoparticles. These peptides form a nanofibrillar network structure upon gelation in aqueous medium at basic pH values (pH 11.0-13.0), and the fabrication of CdS nanoparticles on the gel nanofiber confers the luminescent property to these gels. Atomic force microscopy, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy clearly reveal the presence of CdS nanoparticles in a well-defined array on the gel nanofibers. This is a convenient way to make organic nanofiber-inorganic nanoparticle hybrid nanocomposite systems. The size of the CdS nanoparticles remains almost same before and after deposition on the gel nanofiber. Photoluminescence (PL) measurement of the CdS nanoparticles upon deposition on the gel nanofibers shows a significant blue shift in the emission spectrum of the nanoparticles, and there is a considerable change in the PL gap energy of the CdS nanoparticles after immobilization on different gel nanofibrils. This finding suggests that the optoelectronic properties of CdS nanoparticles can be tuned upon deposition on gel nanofibers without changing the size of the nanoparticles.

Luminescence quantum yields of gold nanoparticles varying with excitation wavelength

NASA Astrophysics Data System (ADS)

Cheng, Yuqing; He, Yingbo; Zhao, Jingyi; Shen, Hongming; Xia, Keyu; Lua, Guowei; Gong, Qihuang

2016-11-01

Luminescence quantum yields (QYs) of gold nanoparticles including nanorods, nanobipyramids and nanospheres are measured elaborately at single nanoparticle level with different excitation wavelengths. It is found that the QYs of the nanostructures are essentially dependent on the excitation wavelength. The QY is higher when the excitation wavelength is blue-detuned and close to the nanoparticles' surface plasmon resonant peak. A phenomenological model based on plasmonic resonator concept is proposed to understand the experimental findings. The excitation wavelength dependent of QY is attributed to the wavelength dependent coupling efficiency between the free electrons oscillation and the intrinsic plasmon resonant radiative mode. These studies should contribute to the understanding of one-photon luminescence from metallic nanostructures and plasmonic surface enhanced spectroscopy.

Thiazole derivative-modified upconversion nanoparticles for Hg2+ detection in living cells

NASA Astrophysics Data System (ADS)

Gu, Bin; Zhou, Yi; Zhang, Xiao; Liu, Xiaowang; Zhang, Yuhai; Marks, Robert; Zhang, Hua; Liu, Xiaogang; Zhang, Qichun

2015-12-01

Mercury ion (Hg2+) is an extremely toxic ion, which will accumulate in human bodies and cause severe nervous system damage. Therefore, the sensitive and efficient monitoring of Hg2+ in human bodies is of great importance. Upconversion nanoparticle (UCNPs) based nano probes exhibit no autofluorescence, deep penetration depth and chemical stability in biological samples, as well as a large anti-stokes shift. In this study, we have developed thiazole-derivative-functionalized UCNPs, and employed an upconversion emission intensity ratio of 540 nm to 803 nm (I540/I803) as a ratiometric signal to detect Hg2+ in living cells showing excellent photo stability and high selectivity. Our nano probe was characterized using transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD). The low cytotoxicity of our probe was confirmed by an MTT assay and the UCL test in HeLa cells was carried out by confocal microscopy. Our results demonstrated that organic-dye-functionalized UCNPs should be a good strategy for detecting toxic metal ions when studying cellular biosystems.Mercury ion (Hg2+) is an extremely toxic ion, which will accumulate in human bodies and cause severe nervous system damage. Therefore, the sensitive and efficient monitoring of Hg2+ in human bodies is of great importance. Upconversion nanoparticle (UCNPs) based nano probes exhibit no autofluorescence, deep penetration depth and chemical stability in biological samples, as well as a large anti-stokes shift. In this study, we have developed thiazole-derivative-functionalized UCNPs, and employed an upconversion emission intensity ratio of 540 nm to 803 nm (I540/I803) as a ratiometric signal to detect Hg2+ in living cells showing excellent photo stability and high selectivity. Our nano probe was characterized using transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD). The low cytotoxicity of our probe was confirmed by an MTT assay and the UCL test in HeLa cells was carried out by confocal microscopy. Our results demonstrated that organic-dye-functionalized UCNPs should be a good strategy for detecting toxic metal ions when studying cellular biosystems. Electronic supplementary information (ESI) available: NMR, MALDI-TOF MS spectra, etc. See DOI: 10.1039/c5nr05286f

Phosphorus and Cu2+ removal by periphytic biofilm stimulated by upconversion phosphors doped with Pr3+-Li.

PubMed

Zhu, Yan; Zhang, Jianhong; Zhu, Ningyuan; Tang, Jun; Liu, Junzhuo; Sun, Pengfei; Wu, Yonghong; Wong, Po Keung

2018-01-01

Upconversion phosphors (UCPs) can convert visible light into luminescence, such as UV, which can regulate the growth of microbes. Based on these fundamentals, the community composition of periphytic biofilms stimulated by UCPs doped with Pr 3+ -Li + was proposed to augment the removal of phosphorus (P) and copper (Cu). Results showed that the biofilms with community composition optimized by UCPs doped with Pr 3+ -Li + had high P and Cu 2+ removal rates. This was partly due to overall bacterial and algal abundance and biomass increases. The synergistic actions of algal, bacterial biomass and carbon metabolic capacity in the Pr-Li stimulated biofilms facilitated the removal of P and Cu 2+ . The results show that the stimulation of periphytic biofilms by lanthanide-doped UCPs is a promising approach for augmenting P and Cu 2+ removal. Copyright © 2017 Elsevier Ltd. All rights reserved.

X-ray Radiation-Controlled NO-Release for On-Demand Depth-Independent Hypoxic Radiosensitization.

PubMed

Fan, Wenpei; Bu, Wenbo; Zhang, Zhen; Shen, Bo; Zhang, Hui; He, Qianjun; Ni, Dalong; Cui, Zhaowen; Zhao, Kuaile; Bu, Jiwen; Du, Jiulin; Liu, Jianan; Shi, Jianlin

2015-11-16

Multifunctional stimuli-responsive nanotheranostic systems are highly desirable for realizing simultaneous biomedical imaging and on-demand therapy with minimized adverse effects. Herein, we present the construction of an intelligent X-ray-controlled NO-releasing upconversion nanotheranostic system (termed as PEG-USMSs-SNO) by engineering UCNPs with S-nitrosothiol (R-SNO)-grafted mesoporous silica. The PEG-USMSs-SNO is designed to respond sensitively to X-ray radiation for breaking down the S-N bond of SNO to release NO, which leads to X-ray dose-controlled NO release for on-demand hypoxic radiosensitization besides upconversion luminescent imaging through UCNPs in vitro and in vivo. Thanks to the high live-body permeability of X-ray, our developed PEG-USMSs-SNO may provide a new technique for achieving depth-independent controlled NO release and positioned radiotherapy enhancement against deep-seated solid tumors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optical transitions of Er3+/Yb3+ codoped TeO2-WO3-Bi2O3 glass.

PubMed

Shen, Xiang; Nie, Qiuhua; Xu, Tiefeng; Gao, Yuan

2005-10-01

Optical absorption and emission properties of the Er3+/Yb3+ codoped TeO2-WO3-Bi2O3 (TWB) glass has been investigated. The transition probabilities, excited state lifetimes, and the branching ratios have been predicted for Er3+ based on the Judd-Ofelt theory. The broad 1.5 microm fluorescence was observed under 970 nm excitation, and its full width at half maximum (FWHM) is 77 nm. The emission cross-section is calculated using the McCumber theory, and the peak emission cross-section is 1.03 x 10(-21) cm2 at 1.531 microm. This value is much larger than those of the silicate and phosphate glasses. Efficient green and weak red upconversion luminescence from Er3+ centers in the glass sample was observed at room temperature, and the upconversion excitation processes have been analyzed.

Magnetic Field Effects on Triplet-Triplet Annihilation in Solutions: Modulation of Visible/NIR Luminescence.

PubMed

Mani, Tomoyasu; Vinogradov, Sergei A

2013-08-06

Photon upconversion based on sensitized triplet-triplet annihilation (TTA) presents interest for such areas as photovoltaics and imaging. Usually energy upconversion is observed as p -type delayed fluorescence from molecules whose triplet states are populated via energy transfer from a suitable triplet donor, followed by TTA. Magnetic field effects (MFE) on delayed fluorescence in molecular crystals are well known; however, there exist only a few examples of MFE on TTA in solutions, and all of them are limited to UV-emitting materials. Here we present MFE on TTA-mediated visible and near infrared (NIR) emission, sensitized by far-red absorbing metalloporphyrins in solutions at room temperature. In addition to visible delayed fluorescence from annihilator, we also observed NIR emission from the sensitizer, occurring as a result of triplet-triplet energy transfer back from annihilator, termed "delayed phosphorescence". This emission also exhibits MFE, but opposite in sign to the annihilator fluorescence.

Hydrothermal synthesis infrared to visible upconversion luminescence of SrMoO4: Er3+/Yb3+ phosphor

NASA Astrophysics Data System (ADS)

Sinha, Shriya; Kumar, Kaushal

2018-04-01

The upconversion emission properties in Er3+/Yb3+ doped SrMoO4 phosphor synthesized via hydrothermal method is investigated upon 980 nm laser light excitation. The crystal structure and morphology of the synthesized phosphor are characterized by X-ray diffraction and field emission scanning electron microscopy. The X-ray diffraction pattern suggests that SrMoO4 phosphor has tetragonal phase structure. The phosphor emits strong green (525 and 552 nm) and red (665 nm) UC emissions along with weak blue (410 and 488 nm) and near infrared (798 nm) emission bands. The color emitted from the phosphor is shifted from yellow to green region with increasing the power density from 15 to 65 W/cm2. The result indicates that the present material is suitable for making infrared to visible up-converts and display devices.

A novel approach to prepare optically active ion doped luminescent materials via electron beam evaporation into ionic liquids

DOE PAGES

Richter, K.; Lorbeer, C.; Mudring, A. -V.

2014-11-10

A novel approach to prepare luminescent materials via electron-beam evaporation into ionic liquids is presented which even allows doping of host lattices with ions that have a strong size mismatch. Thus, to prove this, MgF 2 nanoparticles doped with Eu 3+ were fabricated. The obtained nanoparticles featured an unusually high luminescence lifetime and the obtained material showed a high potential for application.

Systematic assessment of blood circulation time of functionalized upconversion nanoparticles in the chick embryo

NASA Astrophysics Data System (ADS)

Nadort, Annemarie; Liang, Liuen; Grebenik, Ekaterina; Guller, Anna; Lu, Yiqing; Qian, Yi; Goldys, Ewa; Zvyagin, Andrei

2015-12-01

Nanoparticle-based delivery of drugs and contrast agents holds great promise in cancer research, because of the increased delivery efficiency compared to `free' drugs and dyes. A versatile platform to investigate nanotechnology is the chick embryo chorioallantoic membrane tumour model, due to its availability (easy, cheap) and accessibility (interventions, imaging). In our group, we developed this model using several tumour cell lines (e.g. breast cancer, colon cancer). In addition, we have synthesized in-house silica coated photoluminescent upconversion nanoparticles with several functional groups (COOH, NH2, PEG). In this work we will present the systematic assessment of their in vivo blood circulation times. To this end, we injected chick embryos grown ex ovo with the functionalized UCNPs and obtained a small amount of blood at several time points after injection to create blood smears The UCNP signal from the blood smears was quantified using a modified inverted microscope imaging set-up. The results of this systematic study are valuable to optimize biochemistry protocols and guide nanomedicine advancement in the versatile chick embryo tumour model.

Titanium Dioxide/Upconversion Nanoparticles/Cadmium Sulfide Nanofibers Enable Enhanced Full-Spectrum Absorption for Superior Solar Light Driven Photocatalysis.

PubMed

Zhang, Fu; Zhang, Chuan-Ling; Wang, Wan-Ni; Cong, Huai-Ping; Qian, Hai-Sheng

2016-06-22

In this work, we demonstrate an electrospinning technique to fabricate TiO2 /upconversion nanoparticles (UCNPs)/CdS nanofibers on large scale. In addition, the as-prepared TiO2 nanofibers are incorporated with a high population of UCNPs and CdS nanospheres; this results in Förster resonance energy-transfer configurations of the UCNPs, TiO2 , and CdS nanospheres that are in close proximity. Hence, strong fluorescent emissions for the Tm(3+) ions including the (1) G4 →(3) H6 transition are efficiently transferred to TiO2 and the CdS nanoparticles through an energy-transfer process. The as-prepared TiO2 /UCNPs/CdS nanofibers exhibit full-spectrum solar-energy absorption and enable the efficient degradation of organic dyes by fluorescence resonance energy transfer between the UCNPs and TiO2 (or CdS). The UCNPs/TiO2 /CdS nanofibers may also have enhanced energy-transfer efficiency for wide applications in solar cells, bioimaging, photodynamics, and chemotherapy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Double-Targeting Explosible Nanofirework for Tumor Ignition to Guide Tumor-Depth Photothermal Therapy.

PubMed

Zhang, Ming-Kang; Wang, Xiao-Gang; Zhu, Jing-Yi; Liu, Miao-Deng; Li, Chu-Xin; Feng, Jun; Zhang, Xian-Zheng

2018-04-17

This study reports a double-targeting "nanofirework" for tumor-ignited imaging to guide effective tumor-depth photothermal therapy (PTT). Typically, ≈30 nm upconversion nanoparticles (UCNP) are enveloped with a hybrid corona composed of ≈4 nm CuS tethered hyaluronic acid (CuS-HA). The HA corona provides active tumor-targeted functionality together with excellent stability and improved biocompatibility. The dimension of UCNP@CuS-HA is specifically set within the optimal size window for passive tumor-targeting effect, demonstrating significant contributions to both the in vivo prolonged circulation duration and the enhanced size-dependent tumor accumulation compared with ultrasmall CuS nanoparticles. The tumors featuring hyaluronidase (HAase) overexpression could induce the escape of CuS away from UCNP@CuS-HA due to HAase-catalyzed HA degradation, in turn activating the recovery of initially CuS-quenched luminescence of UCNP and also driving the tumor-depth infiltration of ultrasmall CuS for effective PTT. This in vivo transition has proven to be highly dependent on tumor occurrence like a tumor-ignited explosible firework. Together with the double-targeting functionality, the pathology-selective tumor ignition permits precise tumor detection and imaging-guided spatiotemporal control over PTT operation, leading to complete tumor ablation under near infrared (NIR) irradiation. This study offers a new paradigm of utilizing pathological characteristics to design nanotheranostics for precise detection and personalized therapy of tumors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Distance-dependent plasmon-enhanced fluorescence of upconversion nanoparticles using polyelectrolyte multilayers as tunable spacers.

PubMed

Feng, Ai Ling; You, Min Li; Tian, Limei; Singamaneni, Srikanth; Liu, Ming; Duan, Zhenfeng; Lu, Tian Jian; Xu, Feng; Lin, Min

2015-01-14

Lanthanide-doped upconversion nanoparticles (UCNPs) have attracted widespread interests in bioapplications due to their unique optical properties by converting near infrared excitation to visible emission. However, relatively low quantum yield prompts a need for developing methods for fluorescence enhancement. Plasmon nanostructures are known to efficiently enhance fluorescence of the surrounding fluorophores by acting as nanoantennae to focus electric field into nano-volume. Here, we reported a novel plasmon-enhanced fluorescence system in which the distance between UCNPs and nanoantennae (gold nanorods, AuNRs) was precisely tuned by using layer-by-layer assembled polyelectrolyte multilayers as spacers. By modulating the aspect ratio of AuNRs, localized surface plasmon resonance (LSPR) wavelength at 980 nm was obtained, matching the native excitation of UCNPs resulting in maximum enhancement of 22.6-fold with 8 nm spacer thickness. These findings provide a unique platform for exploring hybrid nanostructures composed of UCNPs and plasmonic nanostructures in bioimaging applications.

Enantiopure distorted ribbon-shaped nanographene combining two-photon absorption-based upconversion and circularly polarized luminescence† †Electronic supplementary information (ESI) available: General details, synthesis and spectroscopy data of new compounds. Experimental details on optical, chiroptical, electrochemical and on-surface measurements. Crystal data and structure refinement of compounds 1, and 6. Further details on theoretical calculations and Cartesian coordinates of computed structures. VT-H1NMR, 2D-NMR and HRMS spectra of 1. CCDC 1561552 and 1561553. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8sc00427g

PubMed Central

Cruz, Carlos M.; Márquez, Irene R.; Mariz, Inês F. A.; Blanco, Victor; Sánchez-Sánchez, Carlos; Sobrado, Jesús M.; Martín-Gago, José A.; Cuerva, Juan M.

2018-01-01

Herein we describe a distorted ribbon-shaped nanographene exhibiting unprecedented combination of optical properties in graphene-related materials, namely upconversion based on two-photon absorption (TPA-UC) together with circularly polarized luminescence (CPL). The compound is a graphene molecule of ca. 2 nm length and 1 nm width with edge defects that promote the distortion of the otherwise planar lattice. The edge defects are an aromatic saddle-shaped ketone unit and a [5]carbohelicene moiety. This system is shown to combine two-photon absorption and circularly polarized luminescence and a remarkably long emission lifetime of 21.5 ns. The [5]helicene is responsible for the chiroptical activity while the push–pull geometry and the extended network of sp2 carbons are factors favoring the nonlinear absorption. Electronic structure theoretical calculations support the interpretation of the results. PMID:29780523

Monodisperse Dual-Functional Upconversion Nanoparticles Enabled Near-Infrared Organolead Halide Perovskite Solar Cells.

PubMed

He, Ming; Pang, Xinchang; Liu, Xueqin; Jiang, Beibei; He, Yanjie; Snaith, Henry; Lin, Zhiqun

2016-03-18

Extending the spectral absorption of organolead halide perovskite solar cells from visible into near-infrared (NIR) range renders the minimization of non-absorption loss of solar photons with improved energy alignment. Herein, we report on, for the first time, a viable strategy of capitalizing on judiciously synthesized monodisperse NaYF4 :Yb/Er upconversion nanoparticles (UCNPs) as the mesoporous electrode for CH3 NH3 PbI3 perovskite solar cells and more importantly confer perovskite solar cells to be operative under NIR light. Uniform NaYF4 :Yb/Er UCNPs are first crafted by employing rationally designed double hydrophilic star-like poly(acrylic acid)-block-poly(ethylene oxide) (PAA-b-PEO) diblock copolymer as nanoreactor, imparting the solubility of UCNPs and the tunability of film porosity during the manufacturing process. The subsequent incorporation of NaYF4 :Yb/Er UCNPs as the mesoporous electrode led to a high efficiency of 17.8 %, which was further increased to 18.1 % upon NIR irradiation. The in situ integration of upconversion materials as functional components of perovskite solar cells offers the expanded flexibility for engineering the device architecture and broadening the solar spectral use. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cooperative and non-cooperative sensitization upconversion in lanthanide-doped LiYbF4 nanoparticles.

PubMed

Zou, Qilin; Huang, Ping; Zheng, Wei; You, Wenwu; Li, Renfu; Tu, Datao; Xu, Jin; Chen, Xueyuan

2017-05-18

Lanthanide (Ln 3+ )-doped upconversion nanoparticles (UCNPs) have attracted tremendous interest owing to their potential bioapplications. However, the intrinsic photophysics responsible for upconversion (UC) especially the cooperative sensitization UC (CSU) in colloidal Ln 3+ -doped UCNPs has remained untouched so far. Herein, we report a unique strategy for the synthesis of high-quality LiYbF 4 :Ln 3+ core-only and core/shell UCNPs with tunable particle sizes and shell thicknesses. Energy transfer UC from Er 3+ , Ho 3+ and Tm 3+ and CSU from Tb 3+ were comprehensively surveyed under 980 nm excitation. Through surface passivation, we achieved efficient non-cooperative sensitization UC with absolute UC quantum yields (QYs) of 3.36%, 0.69% and 0.81% for Er 3+ , Ho 3+ and Tm 3+ , respectively. Particularly, we for the first time quantitatively determined the CSU efficiency for Tb 3+ with an absolute QY of 0.0085% under excitation at a power density of 70 W cm -2 . By means of temperature-dependent steady-state and transient UC spectroscopy, we unraveled the dominant mechanisms of phonon-assisted cooperative energy transfer (T > 100 K) and sequential dimer ground-state absorption/excited-state absorption (T < 100 K) for the CSU process in LiYbF 4 :Tb 3+ UCNPs.

Luminescence study of Eu3+ doped GdVO4 nanoparticles: Concentration, particle size, and core/shell effects

NASA Astrophysics Data System (ADS)

Singh, N. Shanta; Ningthoujam, R. S.; Devi, L. Romila; Yaiphaba, N.; Sudarsan, V.; Singh, S. Dorendrajit; Vatsa, R. K.; Tewari, R.

2008-11-01

Nanoparticles of GdVO4 doped with Eu3+ and core/shell of GdVO4:Eu3+/GdVO4 are prepared by urea hydrolysis method using ethylene glycol as capping agent as well as reaction medium at 130 °C. Unit cell volume increases when GdVO4 is doped with Eu3+ indicating the substitution of Gd3+ lattice sites by Eu3+. From luminescence study, it is confirmed that there is no particle size effect on emission positions of Eu3+. Optimum luminescence intensity is found to be in 5-10 at. % Eu3+. Above these concentrations, luminescence intensity decreases due to concentration quenching effect. There is an enhancement in luminescence intensity of core/shell nanoparticles. This has been attributed to the reduction in surface inhomogenities of Eu3+ surroundings by bonding to GdVO4 shell. The lifetime for D50 level increases with annealing and core/shell formation.

The Effect of Inorganic Nanoparticles on the Luminescence Properties of the 5CB Liquid Crystal

NASA Astrophysics Data System (ADS)

Bezrodna, T. V.; Klishevich, G. V.; Curmei, N. D.; Melnyk, V. I.; Nesprava, V. V.

2017-09-01

The luminescence spectral characteristics of nanocomposites based on the 5CB liquid crystal with dispersions of inorganic particles of carbon nanotubes (CNTs), the mineral montmorillonite (MMT), and nanotubes of titanium dioxide TiO2 (TNT) were investigated in the temperature range of 4.3-300 K. The IR absorption spectra of the composites at room temperature in the region of 390-4000 cm-1 were studied. The dependence of the luminescent properties of the composites on the physical properties and parameters of the nanoparticles was studied. It was established that the longwave shift of the luminescence spectra of the composites in relation to the spectra of the pure liquid crystal is related to the specific surface area of the nanoparticles. The longwave shifts of the spectra at room and low temperatures are analyzed.

Enhancement of luminescence emission from GdVO{sub 4}:Er{sup 3+}/Yb{sup 3+} phosphor by Li{sup +} co-doping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gavrilović, Tamara V.; Jovanović, Dragana J., E-mail: draganaj@vinca.rs; Lojpur, Vesna M.

2014-09-15

This paper demonstrates the effects of Li{sup +} co-doping on the structure, morphology, and luminescence properties of GdVO{sub 4}:Er{sup 3+}/Yb{sup 3+} phosphor prepared using a high-temperature solid-state chemistry method. The GdVO{sub 4}:Er{sup 3+}/Yb{sup 3+} powders synthesized with the Li{sup +} co-dopant (in concentrations of 0, 5, 10, and 15 mol%) are characterized by X-ray powder diffraction, scanning electron microscopy, and photoluminescence spectroscopy. Structural analysis showed that powders co-doped with Li{sup +} have larger crystallite sizes and slightly smaller crystal lattice parameters than powders prepared without Li{sup +} ions. Photoluminescence down-conversion (345-nm excitation) and up-conversion (980-nm excitation) spectra show characteristic Er{supmore » 3+} emissions, with the most intense bands peaking at 525 nm ({sup 2}H{sub 11/2}→{sup 4}I{sub 15/2} transition) and 552 nm ({sup 4}S{sub 3/2}→{sup 4}I{sub 15/2}). The intensity of up-conversion emission from GdVO{sub 4}:Er{sup 3+}/Yb{sup 3+} is enhanced (by a factor of four) by co-doping with 5 mol% of Li{sup +} ions. The mechanisms responsible for this emission enhancement are discussed. - Graphical abstract: UC emission spectra for GdVO{sub 4}:1.5-mol% Er{sup 3+}/20-mol% Yb{sup 3+} powders co-doped with different concentrations of Li{sup +} ions, recorded under 980-nm excitation. - Highlights: • 5-mol% Li{sup +} co-doped powders have 400% enhanced up-conversion emission intensity. • 15-mol% Li{sup +} co-doping produces 40% higher emission in down-conversion. • Li{sup +} co-doped powders have larger crystallite size and smaller lattice parameters.« less

Spectral properties and anti-Stokes luminescence of TeO2-BaF2:Ho3+, Ho3+/Yb3+ ceramics and glass excited by 1.9-μm radiation of a Tm:LiYF4 laser

NASA Astrophysics Data System (ADS)

Savikin, A. P.; Egorov, A. S.; Budruev, A. V.; Perunin, I. Yu.; Krasheninnikova, O. V.; Grishin, I. A.

2017-07-01

We demonstrate the up-conversion of Tm:LiYF4 infrared (IR) laser radiation with 1908-nm wavelength into visible light with a spectral maximum at 650 nm by ceramics with a composition of (100 - x)TeO2- xBaF2 - 1 wt % HoF3- yYbF3, where x = 20, 30, or 40 mol % and y = 0 or 0.5 wt %. The samples of 60TeO2-40BaF2 - 1 wt % HoF3 - 0.5 wt % YbF3 exhibited anti-Stokes luminescence at a threshold radiation power density of 1.0-1.5 W cm-2.

Synthesis and property investigation of metal-based nanomaterials for biotechnological applications

NASA Astrophysics Data System (ADS)

Darsanasiri, Nalin Dammika

Luminescent lanthanide-based materials have drawn recent interest due to their applications in in vitro cellular imaging. Sensitive biological analysis requires optical labels with high water dispersibility & stability and excellent luminescent properties. Most literature reported lanthanide complexes with high luminescence intensity are hydrophobic and unstable, limiting their biological applications. This project was designed to incorporate a highly luminescent lanthanide beta-diketonate complex in a silica nanoparticle. Eu(btfa)3dmph complex was synthesized, which exhibits red luminescence at 614 nm with a narrow (15 nm) full with half-maximum (btfa=4,4,4-trifluoro-1-phenyl-1,3-butanedione, dmph=4,7-dimethyl,1,10-phenanthroline). A synthetic procedure was optimized to incorporate the Eu-complex in a silica-based nanoparticle with an average particle diameter of 36 nm. Eu-complex based silica nanoparticles exhibit high stability and water-dispersibility with a luminescence quantum yield of 10 %. The nanoparticles showed antimicrobial activity against clinically important E.coli, S.aureus and S.epidermidis. Synthesis, materials characterization, and antimicrobial studies of the complex and the nanoparticles was discussed in the first part of this thesis. Nanotechnology is emerging as a new interdisciplinary field combining biology, chemistry, physics, and material science. Recent advances promise developments in the synthesis, modification and practical applications of polymer-coated manganese (Mn)-based zinc oxide (ZnO) nanoparticles (NPs). The size distribution, shape, and surface modification of metal-based ZnO nanoparticles are the key factors determining their specific physical properties. Due to the strong antibacterial properties and low toxicity towards mammalian cells, ZnO NPs have been successfully used in a wide range of applications including wound dressing, protective clothing, antibacterial surfaces, food preservation, and cosmetics as biocidal and disinfecting agents. In this study, cotton textiles with antimicrobial activity were developed by incorporating polymer-coated Mn-doped ZnO nanoparticles. Antimicrobial potential of synthesized Mn-doped zinc oxide (ZnO) nanoparticles against two bacteria strains ( Escherichia coli as Gram-negative bacteria, Staphylococcus aureus as Gram-positive bacteria) in liquid and solid phases was studied in this work. Polymer-coated Mn-doped ZnO nanoparticles were prepared by the modified co-precipitation method. Characterization of the nanoparticles was carried out using Ultra-violet visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). The average particle size of the nanoparticles was found to be less than 15 nm. The antibacterial activity of the nanoparticles was evaluated using minimum inhibitory concentration (MIC) and agar diffusion method. Disk diffusion studies revealed that the nanoparticles have excellent antimicrobial activity against E.coli and S.aureus bacterial species. Therefore, it was concluded that the polymer-coated Mn-doped ZnO nanoparticles were excellent antibacterial agents with potential clinical applications.

One-pot green synthesis of luminescent gold nanoparticles using imidazole derivative of chitosan.

PubMed

Nazirov, Alexander; Pestov, Alexander; Privar, Yuliya; Ustinov, Alexander; Modin, Evgeny; Bratskaya, Svetlana

2016-10-20

Water soluble luminescent gold nanoparticles with average size 2.3nm were for the first time synthesized by completely green method of Au(III) reduction using chitosan derivative-biocompatible nontoxic N-(4-imidazolyl)methylchitosan (IMC) as both reducing and stabilizing agent. Reduction of Au(III) to gold nanoparticles in IMC solution is a slow process, in which coordination power of biopolymer controls both reducing species concentration and gold crystal growth rate. Gold nanoparticles formed in IMC solution do not manifest surface plasmon resonance, but exhibit luminescence at 375nm under UV light excitation at 230nm. Due to biological activity of imidazolyl-containing polymers and their ability to bind proteins and drugs, the obtained ultra-small gold nanoparticles can find an application for biomolecules detection, bio-imaging, drug delivery, and catalysis. Very high catalytic activity (as compared to gold nanoparticles obtained by other green methods) was found for Au/IMC nanoparticles in the model reaction of p-nitrophenol reduction providing complete conversion of p-nitrophenol to p-aminophenol within 180-190s under mild conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

A cobalt oxyhydroxide-modified upconversion nanosystem for sensitive fluorescence sensing of ascorbic acid in human plasma

NASA Astrophysics Data System (ADS)

Cen, Yao; Tang, Jun; Kong, Xiang-Juan; Wu, Shuang; Yuan, Jing; Yu, Ru-Qin; Chu, Xia

2015-08-01

Ascorbic acid (AA), a potent antioxidant readily scavenging reactive species, is a crucial micronutrient involved in many biochemical processes. Here, we have developed a cobalt oxyhydroxide (CoOOH)-modified upconversion nanosystem for fluorescence sensing of AA activity in human plasma. The nanosystem consists of upconversion nanoparticles (UCNPs) NaYF4:30% Yb,0.5% Tm@NaYF4, which serve as energy donors, and CoOOH nanoflakes formed on the surface of UCNPs, which act as efficient energy acceptors. The fluorescence resonance energy transfer (FRET) process from the UCNPs to the absorbance of the CoOOH nanoflakes occurs in the nanosystem. The AA-mediated specific redox reaction reduces CoOOH into Co2+, leading to the inhibition of FRET, and resulting in the recovery of upconversion emission spectra. On the basis of these features, the nanosystem can be used for sensing AA activity with sensitivity and selectivity. Moreover, due to the minimizing background interference provided by UCNPs, the nanosystem has been applied to monitoring AA levels in human plasma sample with satisfactory results. The proposed approach may potentially provide an analytical platform for research and clinical diagnosis of AA related diseases.Ascorbic acid (AA), a potent antioxidant readily scavenging reactive species, is a crucial micronutrient involved in many biochemical processes. Here, we have developed a cobalt oxyhydroxide (CoOOH)-modified upconversion nanosystem for fluorescence sensing of AA activity in human plasma. The nanosystem consists of upconversion nanoparticles (UCNPs) NaYF4:30% Yb,0.5% Tm@NaYF4, which serve as energy donors, and CoOOH nanoflakes formed on the surface of UCNPs, which act as efficient energy acceptors. The fluorescence resonance energy transfer (FRET) process from the UCNPs to the absorbance of the CoOOH nanoflakes occurs in the nanosystem. The AA-mediated specific redox reaction reduces CoOOH into Co2+, leading to the inhibition of FRET, and resulting in the recovery of upconversion emission spectra. On the basis of these features, the nanosystem can be used for sensing AA activity with sensitivity and selectivity. Moreover, due to the minimizing background interference provided by UCNPs, the nanosystem has been applied to monitoring AA levels in human plasma sample with satisfactory results. The proposed approach may potentially provide an analytical platform for research and clinical diagnosis of AA related diseases. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03588k

Multifunctional rare-Earth vanadate nanoparticles: luminescent labels, oxidant sensors, and MRI contrast agents.

PubMed

Abdesselem, Mouna; Schoeffel, Markus; Maurin, Isabelle; Ramodiharilafy, Rivo; Autret, Gwennhael; Clément, Olivier; Tharaux, Pierre-Louis; Boilot, Jean-Pierre; Gacoin, Thierry; Bouzigues, Cedric; Alexandrou, Antigoni

2014-11-25

Collecting information on multiple pathophysiological parameters is essential for understanding complex pathologies, especially given the large interindividual variability. We report here multifunctional nanoparticles which are luminescent probes, oxidant sensors, and contrast agents in magnetic resonance imaging (MRI). Eu(3+) ions in an yttrium vanadate matrix have been demonstrated to emit strong, nonblinking, and stable luminescence. Time- and space-resolved optical oxidant detection is feasible after reversible photoreduction of Eu(3+) to Eu(2+) and reoxidation by oxidants, such as H2O2, leading to a modulation of the luminescence emission. The incorporation of paramagnetic Gd(3+) confers in addition proton relaxation enhancing properties to the system. We synthesized and characterized nanoparticles of either 5 or 30 nm diameter with compositions of GdVO4 and Gd0.6Eu0.4VO4. These particles retain the luminescence and oxidant detection properties of YVO4:Eu. Moreover, the proton relaxivity of GdVO4 and Gd0.6Eu0.4VO4 nanoparticles of 5 nm diameter is higher than that of the commercial Gd(3+) chelate compound Dotarem at 20 MHz. Nuclear magnetic resonance dispersion spectroscopy showed a relaxivity increase above 10 MHz. Complexometric titration indicated that rare-earth leaching is negligible. The 5 nm nanoparticles injected in mice were observed with MRI to concentrate in the liver and the bladder after 30 min. Thus, these multifunctional rare-earth vanadate nanoparticles pave the way for simultaneous optical and magnetic resonance detection, in particular, for in vivo localization evolution and reactive oxygen species detection in a broad range of physiological and pathophysiological conditions.

Luminescence enhancement in nanocomposite consisting of polyvinyl alcohol incorporated gold nanoparticles and Nile blue 690 perchlorate.

PubMed

Chubinidze, Ketevan; Partsvania, Besarion; Sulaberidze, Tamaz; Khuskivadze, Aleksandre; Davitashvili, Elene; Koshoridze, Nana

2014-11-01

We have experimentally demonstrated that the emission of visible light from the polymer matrix doped with luminescent dye and gold nanoparticles (GNPs) can be enhanced with the use of surface plasmon coupling. GNPs can enhance the luminescence intensity of nearby luminescent dye because of the interactions between the dipole moments of the dye and the surface plasmon field of the GNPs. The electric charge on the GNPs and the distance between GNPs and luminescent dye molecules have a significant effect on the luminescence intensity, and this enhancement depends strongly upon the excitation wavelength of the pumping laser source. In particular, by matching the plasmon frequency of GNPs to the frequency of the laser light source we have observed a strong luminescence enhancement of the nanocomposite consisting of GNPs coupled with luminescent dye Nile blue 690 perchlorate. This ability of controlling luminescence can be beneficially used in developing contrast agents for highly sensitive and specific optical sensing and imaging. This opens new possibilities for plasmonic applications in the solar energy field.

High quality polyacrylic acid modified multifunction luminescent nanorods for tri-modality bioimaging, in vivo long-lasting tracking and biodistribution

NASA Astrophysics Data System (ADS)

Yi, Zhigao; Lu, Wei; Liu, Hongrong; Zeng, Songjun

2014-12-01

Polyacrylic acid (PAA) modified NaYF4:Gd/Yb/Er upconversion nanorods (denoted as PAA-UCNRs) are demonstrated for tri-modal upconversion (UC) optical, computed X-ray tomography (CT), and magnetic resonance imaging (MRI). The hydrophilic PAA-UCNRs were obtained from hydrophobic oleic acid (OA) capped UCNRs (denoted as OA-UCNRs) using a ligand exchange method. The as-prepared UCNRs with a hexagonal phase structure present high monodispersity. These PAA-UCNRs are successfully used as ideal probes for in vivo UC luminescence bioimaging and synergistic X-ray and UC bioimaging. Moreover, X-ray CT imaging reveals that PAA-UCNRs can act as contrast agents for improved detection of the liver and spleen. In addition, a significant signal enhancement in the liver is observed in in vivo MRI, indicating that PAA-UCNRs are ideal T1-weighted MRI agents. More importantly, in vivo long-term tracking based on these PAA-UCNRs in the live mice and the corresponding ex vivo bioimaging of isolated organs also verify the translocation of PAA-UCNRs from the liver to the spleen, and the observed intense UC signals from the feces reveal the biliary excretion mechanism of these UCNRs. These findings contribute to understanding of the translocation and potential route for excretion of PAA-UCNRs, which can provide an important guide for the diagnosis and detection of diseases based on these UCNRs.Polyacrylic acid (PAA) modified NaYF4:Gd/Yb/Er upconversion nanorods (denoted as PAA-UCNRs) are demonstrated for tri-modal upconversion (UC) optical, computed X-ray tomography (CT), and magnetic resonance imaging (MRI). The hydrophilic PAA-UCNRs were obtained from hydrophobic oleic acid (OA) capped UCNRs (denoted as OA-UCNRs) using a ligand exchange method. The as-prepared UCNRs with a hexagonal phase structure present high monodispersity. These PAA-UCNRs are successfully used as ideal probes for in vivo UC luminescence bioimaging and synergistic X-ray and UC bioimaging. Moreover, X-ray CT imaging reveals that PAA-UCNRs can act as contrast agents for improved detection of the liver and spleen. In addition, a significant signal enhancement in the liver is observed in in vivo MRI, indicating that PAA-UCNRs are ideal T1-weighted MRI agents. More importantly, in vivo long-term tracking based on these PAA-UCNRs in the live mice and the corresponding ex vivo bioimaging of isolated organs also verify the translocation of PAA-UCNRs from the liver to the spleen, and the observed intense UC signals from the feces reveal the biliary excretion mechanism of these UCNRs. These findings contribute to understanding of the translocation and potential route for excretion of PAA-UCNRs, which can provide an important guide for the diagnosis and detection of diseases based on these UCNRs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05161k

Silicon nanoparticle-functionalized fiberglass pads for sampling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mantey, Kevin; Nayfeh, Munir H.; Al-Hreish, Bahjat

2011-03-15

We used wet treatment to immobilize luminescent silicon nanoparticles on industrial glass fibers to impart optical and chemical functions to the fiber. Carpets or pads consisting of thousands of fibers are processed in parallel, enhancing the sensitivity of detection and the sampled volume. Treated pads exhibit strong luminescence, characteristic of the luminescence of the particles; showing no shift, broadening, or reduction of quantum efficiency. We demonstrate that drawing material by the pad due to physical adsorption can be reversed. We also demonstrate that allylamine can be covalently attached by photoinduced irradiation reactions, which results in imprinting the amine emission spectrum,more » providing spectral recognition. The imprint accompanied with a blue-shifting of the luminescence spectrum of the probe, allowing examination of the effect of termination on the nanoparticle structure. The shift is found to be consistent with an increase in the bandgap of the Si nanoparticle and is consistent with Quantum Monte Carlo calculations. In addition to sampling, the nano probe pad has the potential to enable a variety of biomedical applications through subsequent attachment.« less

Development of novel edible luminescent nanoparticle sensors

NASA Astrophysics Data System (ADS)

Jalalian, Sanaz

This project has developed a novel class of edible hydrocolloid food nanosensors which are doped with luminescent chromophores and investigated whether they can be used to provide information about the local food matrix - temperature, oxygen concentration, and the presence of food-borne pathogens. The luminescence properties of the probes such as phosphorescence and fluorescence provide the sensor sensitivity to the food properties. Hydrocolloid nanoparticles were made from gelatin and starch with diameters ranging from 50 to ˜200 nm and labeled with food grade luminescent probes. The chromophore was covalently and non-covalently attached to the nanoparticle and the photophysical properties of the probe in the food system were studied. Temperature sensors were developed by using the phosphorescence sensitivity of a chromophore to temperature. Experiments with two different probes, namely erythrosine B labeled gelatin nanoparticles and phloxine B labeled gelatin nanoparticles have demonstrated that both probes can be effectively used as temperature sensors in liquid and solid food. The Van't Hoff plots of ln(IDF/IP) versus 1/T vary monotonically over a relatively wide temperature range and thus provide a basis for estimating temperature from measurements of phosphorescence and delayed fluorescence. The tests indicated that the presence of some ingredients such as tannin and anthocyanins in the composition of the food may prohibit the use of gelatin nanoparticle probes due to precipitation of gelatin nanoparticles. The luminescence quenching of the probe by oxygen was used to develop a nanoparticle sensor for oxygen. The results of experiments on liquid and solid food samples indicate that erythrosine B labeled gelatin nanoparticles can be used as a probe to detect the presence or absence of oxygen in some liquid foods. Precise control of oxygen concentration in solutions will pose a challenge as has been observed in this study. The probe did not work as an appropriate oxygen sensor in the case of solid food samples with low relative humidity. The use of gelatin nanoparticles as a sensor to detect the presence of food-borne pathogens requires a measurable change in the spectrum of fluorescence resonance energy transfer between two chromophores which was not observed in the tests.

Red-light-controllable liquid-crystal soft actuators via low-power excited upconversion based on triplet-triplet annihilation.

PubMed

Jiang, Zhen; Xu, Ming; Li, Fuyou; Yu, Yanlei

2013-11-06

A red-light-controllable soft actuator has been achieved, driven by low-power excited triplet-triplet annihilation-based upconversion luminescence (TTA-UCL). First, a red-to-blue TTA-based upconversion system with a high absolute quantum yield of 9.3 ± 0.5% was prepared by utilizing platinum(II) tetraphenyltetrabenzoporphyrin (PtTPBP) as the sensitizer and 9,10-bis(diphenylphosphoryl)anthracene (BDPPA) as the annihilator. In order to be employed as a highly effective phototrigger of photodeformable cross-linked liquid-crystal polymers (CLCPs), the PtTPBP&BDPPA system was incorporated into a rubbery polyurethane film and then assembled with an azotolane-containing CLCP film. The generating assembly film bent toward the light source when irradiated with a 635 nm laser at low power density of 200 mW cm(-2) because the TTA-UCL was effectively utilized by the azotolane moieties in the CLCP film, inducing their trans-cis photoisomerization and an alignment change of the mesogens via an emission-reabsorption process. It is the first example of a soft actuator in which the TTA-UCL is trapped and utilized to create photomechanical effect. Such advantages of using this novel red-light-controllable soft actuator in potential biological applications have also been demonstrated as negligible thermal effect and its excellent penetration ability into tissues. This work not only provides a novel photomanipulated soft actuation material system based on the TTA-UCL technology but also introduces a new technological application of the TTA-based upconversion system in photonic devices.

Magnetic and luminescent properties of multifunctional GdF3:Eu3+ nanoparticles

NASA Astrophysics Data System (ADS)

Wong, Hon-Tung; Chan, H. L. W.; Hao, J. H.

2009-07-01

Multifunctional GdF3:Eu3+ nanoparticles were synthesized using a hydrothermal method. Photoluminescent excitation and emission spectra, and lifetime were measured. The average lifetime of the nanoparticles is about 11 ms. The nanoparticle exhibits paramagnetism at both 293 and 77 K, ascribing to noninteracting localized nature of the magnetic moment in the compound. The magnetic properties of GdF3:Eu3+ is intrinsic to the Gd3+ ions, which is unaffected by the doping concentration of the Eu3+ luminescent centers. A measured magnetization of approximately 2 emu/g is close to reported values of other nanoparticles for bioseparation.

Octoxy capped Si nanoparticles synthesized by homogeneous reduction of SiCl4 with crown ether alkalide.

PubMed

Sletnes, M; Maria, J; Grande, T; Lindgren, M; Einarsrud, M-A

2014-02-07

Blue-green luminescent octoxy capped Si nanoparticles were synthesized via homogeneous reduction of SiCl4 with the crown ether alkalide K(+)(15-crown-5)2K(-) in tetrahydrofuran. The Si nanoparticles were characterized with respect to size, crystal structure, morphology, surface termination, optical properties and stability. Si diamond structure nanoparticles with narrow size distributions, and average diameters ranging from 3 to 7 nm were obtained. A finite-size effect on the lattice dimensions was observed, in the form of an expansion of the [220] lattice planes of smaller Si nanoparticles. The concentration of SiCl4 was found to be the most important parameter governing the particle size and size distribution. The octoxy capped particles were stable under an ambient atmosphere for at least one month, but exposure to water made them prone to oxidation. An average radiative recombination lifetime of 8.8 ns was measured for the blue-green luminescence. The luminescence appears to originate from surface defects, rather than from quantum confinement.

Luminescence study on Eu3+ doped Y2O3 nanoparticles: particle size, concentration and core-shell formation effects

NASA Astrophysics Data System (ADS)

Robindro Singh, L.; Ningthoujam, R. S.; Sudarsan, V.; Srivastava, Iti; Dorendrajit Singh, S.; Dey, G. K.; Kulshreshtha, S. K.

2008-02-01

Nanoparticles of Eu3+ doped Y2O3 (core) and Eu3+ doped Y2O3 covered with Y2O3 shell (core-shell) are prepared by urea hydrolysis for 3 h in ethylene glycol medium at a relatively low temperature of 140 °C, followed by heating at 500 and 900 °C. Particle sizes determined from x-ray diffraction and transmission electron microscopic studies are 11 and 18 nm for 500 and 900 °C heated samples respectively. Based on the luminescence studies of 500 and 900 °C heated samples, it is confirmed that there is no particle size effect on the peak positions of Eu3+ emission, and optimum luminescence intensity is observed from the nanoparticles with a Eu3+ concentration of 4-5 at.%. A luminescence study establishes that the Eu3+ environment in amorphous Y (OH)3 is different from that in crystalline Y2O3. For a fixed concentration of Eu3+ doping, there is a reduction in Eu3+ emission intensity for core-shell nanoparticles compared to that of core nanoparticles, and this has been attributed to the concentration dilution effect. Energy transfer from the host to Eu3+ increases with increase of crystallinity.

Spectral-kinetic characteristics of luminescence of pentaerythritol tetranitrate with inclusions of iron nanoparticles upon explosion induced by laser pulses

NASA Astrophysics Data System (ADS)

Aduev, B. P.; Nurmukhametov, D. R.; Belokurov, G. M.; Nelyubina, N. V.; Gudilin, A. V.

2017-03-01

Spectral-kinetic characteristics of luminescence of tetranitropentaeritrite with inclusions of iron nanoparticles upon an explosion induced by laser pulses are measured with high temporal resolution. It is shown that the luminescence occurring during exposure to the laser pulse is a result of initiating a chemical reaction in tetranitropentaeritrite and is chemiluminescence. The glow is presumably associated with the excited nitrogen dioxide, NO2, which is formed by the rupture of O-NO2 bond in the tetranitropentaeritrite molecule.

Bioimaging and toxicity assessments of near-infrared upconversion luminescent NaYF4:Yb,Tm nanocrystals.

PubMed

Zhou, Jia-Cai; Yang, Zheng-Lin; Dong, Wei; Tang, Ruo-Jin; Sun, Ling-Dong; Yan, Chun-Hua

2011-12-01

In vitro or in vivo bioimaging utilizing the upconversion (UC) luminescence of rare earth fluoride nanocrystals (NCs) has attracted much attention, especially for Yb(3+)/Tm(3+) doped NCs with a near-infrared (NIR) UC emission at 800 nm. Herein, water-soluble NaYF(4):Yb,Tm NCs with strong NIR UC emission were synthesized with a solvothermal method. In vitro and in vivo bioimaging and toxicity assessments were carried out with HeLa cell and Caenorhabditis elegans (C. elegans) cases, respectively. NaYF(4):Yb,Tm NCs afforded an efficient NIR image of the HeLa cells with an incubation concentration of 10 μg mL(-1), and CCK-8 assay revealed a low cytotoxicity. Fed with Escherichia coli (E. coli) and NCs together, the C. elegans showed a NIR image in the gut from the pharynx to the anus. Further, these NCs could be excreted out when those worms were then fed with only E. coli. Toxicity studies were further addressed with protein expression, life span, egg production, egg viability, and growth rate of the worms in comparison with those of the intact ones. The feeding of rare earth fluoride NCs with a dose of 100 μg does not arise obvious toxicity effect from the growth to procreation. The in vitro and in vivo studies confirm that NaYF(4):Yb,Tm NCs could be served as an excellent NIR emission bioprobe with low toxicity. Copyright © 2011 Elsevier Ltd. All rights reserved.

Tuning the morphology, luminescence and magnetic properties of hexagonal-phase NaGdF4: Yb, Er nanocrystals via altering the addition sequence of the precursors

NASA Astrophysics Data System (ADS)

Zhao, Shuwen; Xia, Donglin; Zhao, Ruimin; Zhu, Hao; Zhu, Yiru; Xiong, Yuda; Wang, Youfa

2017-01-01

Hexagonal-phase NaGdF4: Yb, Er upconversion nanocrystals (UCNCs) with tunable morphology and properties were successfully prepared via a thermal decomposition method. The influences of the adding sequence of the precursors on the morphology, chemical composition, luminescence and magnetic properties were investigated by transmission electron microscopy (TEM), inductively coupled plasma-atomic emission spectrometry (ICP-AES), upconversion (UC) spectroscopy, and a vibrating sample magnetometer (VSM). It was found that the resulting nanocrystals, with different sizes ranging from 24 to 224 nm, are in the shape of spheres, hexagonal plates and flakes; moreover, the composition percentage of Yb3+-Er3+ and Gd3+ ions was found to vary in a regular pattern with the adding sequence. Furthermore, the intensity ratios of emission colors (f g/r, f g/p), and the magnetic mass susceptibility of hexagonal-phase NaGdF4: Yb, Er nanocrystals change along with the composition of the nanocrystals. A positive correlation between the susceptibility and f g/r of NaGdF4: Yb, Er was proposed. The decomposition processes of the precursors were investigated by a thermogravimetric (TG) analyzer. The result indicated that the decomposition of the resolved lanthanide trifluoroacetate is greatly different from lanthanide trifluoroacetate powder. It is of tremendous help to recognize the decomposition process of the precursors and to understand the related reaction mechanism.

Room temperature synthesis of β-NaGdF 4 : RE 3+ (RE= Eu, Er) nanocrystallites and their luminescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tessitore, Gabriella; Mudring, Anja-Verena; Kr?mer, Karl W.

In this study, a room temperature synthesis was developed for phase pure β-NaGdF 4 nanocrystallites as well as 5, 10, and 20% Eu 3+ or 5% Er 3+ doped material. Rare earth acetates and NaCl react in a 1:2 M ratio with a variable excess of NH 4F in ethylene glycol within 24 hours. Since the thermodynamic stability of the hexagonal phase decreases along the lanthanide series, a larger excess of NH 4F was required for the synthesis of luminescent samples doped with the smaller Er 3+ ions than for Eu 3+ doped or pure β-NaGdF 4. The materials weremore » characterized by powder X-ray diffraction, electron microscopy, and luminescence spectroscopy. The Eu 3+-doped samples show 5D 0→ 7F J and 5D 1→ 7F J luminescence after Eu 3+ excitation at 394 nm or Gd 3+ excitation at 273 nm and 308 nm. The ratio of 5D 1 vs. 5D 0 luminescence is influenced by the excitation wavelength and the Eu 3+ concentration. Lastly, the Er 3+-doped samples show green and red upconversion luminescence, respectively, from the 2H 11/2+ 4S 3/2→ 4I 15/2 and 4F 9/2→ 4I 15/2 transitions after 970 nm excitation.« less

Room temperature synthesis of β-NaGdF 4 : RE 3+ (RE= Eu, Er) nanocrystallites and their luminescence

DOE PAGES

Tessitore, Gabriella; Mudring, Anja-Verena; Kr?mer, Karl W.

2017-09-01

In this study, a room temperature synthesis was developed for phase pure β-NaGdF 4 nanocrystallites as well as 5, 10, and 20% Eu 3+ or 5% Er 3+ doped material. Rare earth acetates and NaCl react in a 1:2 M ratio with a variable excess of NH 4F in ethylene glycol within 24 hours. Since the thermodynamic stability of the hexagonal phase decreases along the lanthanide series, a larger excess of NH 4F was required for the synthesis of luminescent samples doped with the smaller Er 3+ ions than for Eu 3+ doped or pure β-NaGdF 4. The materials weremore » characterized by powder X-ray diffraction, electron microscopy, and luminescence spectroscopy. The Eu 3+-doped samples show 5D 0→ 7F J and 5D 1→ 7F J luminescence after Eu 3+ excitation at 394 nm or Gd 3+ excitation at 273 nm and 308 nm. The ratio of 5D 1 vs. 5D 0 luminescence is influenced by the excitation wavelength and the Eu 3+ concentration. Lastly, the Er 3+-doped samples show green and red upconversion luminescence, respectively, from the 2H 11/2+ 4S 3/2→ 4I 15/2 and 4F 9/2→ 4I 15/2 transitions after 970 nm excitation.« less

A Novel Approach to Synthesise a Dual-Mode Luminescent Composite Pigment for Uncloneable High-Security Codes to Combat Counterfeiting.

PubMed

Kanika; Kumar, Pawan; Singh, Satbir; Gupta, Bipin Kumar

2017-12-01

A strategy is demonstrated to protect valuable items, such as currency, pharmaceuticals, important documents, etc. against counterfeiting, by marking them with luminescent security codes. These luminescent security codes were printed by employing luminescent ink formulated from a cost effective dual-mode luminescent composite pigment of Gd 1.7 Yb 0.2 Er 0.1 O 3 and Zn 0.98 Mn 0.02 S phosphors using commercially available PVC Gold medium. In the composite, Gd 1.7 Yb 0.2 Er 0.1 O 3 and Zn 0.98 Mn 0.02 S account for upconversion and downconversion processes, respectively. The synthesis procedure of the composite involves the admixing of Gd 1.7 Yb 0.2 Er 0.1 O 3 nanorods and Zn 0.98 Mn 0.02 S phosphor, synthesised by hydrothermal and facile solid-state reaction methods, respectively. The structural, morphological, microstructural, and photoluminescent features of Gd 1.7 Yb 0.2 Er 0.1 O 3 nanorods, Zn 0.98 Mn 0.02 S phosphor and composite were characterised by using XRD, SEM, TEM, and photoluminescence (PL) techniques, respectively. The distribution of PL intensity of the printed pattern was examined by using confocal PL mapping microscopy. The obtained results reveal that security codes printed using ink formulated from this bi-luminescent composite pigment provide dual-stage security against counterfeiting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Up-conversion nanoparticles sensitized inverse opal photonic crystals enable efficient water purification under NIR irradiation

NASA Astrophysics Data System (ADS)

Zhang, Yuanyuan; Wang, Lili; Ma, Xiumei; Ren, Junfeng; Sun, Qinxing; Shi, Yongsheng; Li, Lin; Shi, Jinsheng

2018-03-01

A novel porous monolayer inverse opal (IO) structure was prepared by a simple sol-gel method combined with a self-assembly PS photonic crystal (PC) as template. By prolonging deposition time of PS spheres, three-dimensional multilayer TiO2 IOPC was also fabricated. Up-conversion nanoparticles (UCNPs) were selected to sensitize TiO2 IOPCs. Photocatalytic activity of as-prepared materials was investigated by disinfection of bacteria and organic pollutant degradation. Under NIR light irradiation, a large improvement in bacterial inactivation and photodegradation efficiency could be seen for NYF/TiO2 composites in comparison with other samples. As for monolayer NYF/TiO2, water disinfection of 100% inactivation of bacteria is realized within 11 h and kinetic constant of RhB degradation is 0.133 h-1, which is about 10 times higher than that of pure TiO2 IOPCs. Reasons of enhanced photocatalytic activity were systematically investigated and a possible mechanism for NIR-driven photocatalysis was reasonably proposed.

Nanocomplexes of Photolabile Polyelectrolyte and Upconversion Nanoparticles for Near-Infrared Light-Triggered Payload Release.

PubMed

Xiang, Jun; Ge, Feijie; Yu, Bing; Yan, Qiang; Shi, Feng; Zhao, Yue

2018-06-07

A new approach to encapsulating charged cargo molecules into a nanovector and subsequently using near-infrared (NIR) light to trigger the release is demonstrated. NIR light-responsive nanovector was prepared through electrostatic interaction-driven complexation between negatively charged silica-coated upconversion nanoparticles (UCNP@silica, 87 nm hydrodynamic diameter, polydispersity index ∼0.05) and a positively charged UV-labile polyelectrolyte bearing pendants of poly(ethylene glycol) and o-nitrobenzyl side groups; whereas charged fluorescein (FLU) was loaded through a co-complexation process. By controlling the amount of polyelectrolyte, UCNP@silica can be covered by the polymer, whereas remaining dispersed in aqueous solution. Under 980 nm laser excitation, UV light emitted by UCNP is absorbed by photolytic side groups within polyelectrolyte, which results in cleavage of o-nitrobenzyl groups and formation of carboxylic acid groups. Such NIR light-induced partial reversal of positive charge to negative charge on the polyelectrolyte layer disrupts the equilibrium among UCNP@silica, polyelectrolyte, and FLU and, consequently, leads to release of FLU molecules.

Preparation of K+-Doped Core-Shell NaYF4:Yb, Er Upconversion Nanoparticles and its Application for Fluorescence Immunochromatographic Assay of Human Procalcitonin.

PubMed

Tang, Jie; Lei, Lijiang; Feng, Hui; Zhang, Hongman; Han, Yuwang

2016-11-01

In the present study, we reported a convenient route to prepare well dispersed and functionalized K + -doped core-shell upconversion nanoparticles (UCP) by layer-by-layer (LbL) assembly of polyelectrolytes. UCP was firstly transferred to aqueous phase using cationic surfactant cetyl trimethyl ammonium bromide (CTAB) via hydrophobic interaction without removing the existing oleic acid (OA). Then the positively charged hydrophilic UCP@CTAB was further alternately deposited with negatively charged [poly (sodium 4-styrenesulfonate)] (PSS), positively charged [poly (allylamine hydrochloride)] (PAH) and negatively charged [poly (acrylic acid)] (PAA). The final carboxyl functionalized UCP@CTAB@PSS@PAH@PAA was then conjugated with monoclonal antibody1 (AB1) of procalcitonin (PCT), resulting in successful detection of PCT antigens based on the immunochromatographic assay (ICA). Linear response was achieved from 0 to 10 ng/mL, and the lowest limit of detection (LLD) was 0.18 ng/mL.

Distance-Dependent Plasmon-Enhanced Fluorescence of Upconversion Nanoparticles using Polyelectrolyte Multilayers as Tunable Spacers

PubMed Central

Feng, Ai Ling; You, Min Li; Tian, Limei; Singamaneni, Srikanth; Liu, Ming; Duan, Zhenfeng; Lu, Tian Jian; Xu, Feng; Lin, Min

2015-01-01

Lanthanide-doped upconversion nanoparticles (UCNPs) have attracted widespread interests in bioapplications due to their unique optical properties by converting near infrared excitation to visible emission. However, relatively low quantum yield prompts a need for developing methods for fluorescence enhancement. Plasmon nanostructures are known to efficiently enhance fluorescence of the surrounding fluorophores by acting as nanoantennae to focus electric field into nano-volume. Here, we reported a novel plasmon-enhanced fluorescence system in which the distance between UCNPs and nanoantennae (gold nanorods, AuNRs) was precisely tuned by using layer-by-layer assembled polyelectrolyte multilayers as spacers. By modulating the aspect ratio of AuNRs, localized surface plasmon resonance (LSPR) wavelength at 980 nm was obtained, matching the native excitation of UCNPs resulting in maximum enhancement of 22.6-fold with 8 nm spacer thickness. These findings provide a unique platform for exploring hybrid nanostructures composed of UCNPs and plasmonic nanostructures in bioimaging applications. PMID:25586238

Strain-sensitive upconversion for imaging biological forces (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lay, Alice; Wisser, Michael; Lin, Yu; Narayan, Tarun; Krieg, Michael; Atre, Ashwin; Goodman, Miriam; Dionne, Jennifer A.

2016-09-01

Nearly all diseases can be traced back to abnormal mechanotransduction, but few sensors can reliably measure biologically-relevant forces in vivo. Here, we investigate sub-25nm lanthanide-doped upconverting nanoparticles as novel optical force probes, which provide several biocompatible features: sharp emission peaks with near infrared illumination, a high signal-to-noise ratio, and photostability. To increase force sensitivity, we include d-metal doping in the nanoparticles; the d-metal siphons energy from the lanthanide ions with an efficiency that varies with pressure. We synthesize cubic-phase NaYF4: Er3+,Yb3+ nanoparticles doped with 0-5% Mn2+ and compress them in a hydrostatic environment using a diamond anvil cell. When illuminated at 980nm, the nanoparticles show sharp emission peaks centered at wavelengths of 522nm, 545nm, and 660nm. In 20nN increments, up to 700nN, the ratio of the red-to-green peaks in 0% Mn-doped nanoparticles increases by nearly 30%, resulting in a perceived color change from orange to red. In contrast, the 1% Mn-doped samples exhibit little color change but a large 40% decrease in upconversion intensity. In both cases, the red-to-green ratio varies linearly with strain and the optical properties are recoverable upon release. We further use atomic force microscopy to characterize optical responses at lower, pico-Newton to nano-Newton forces. To demonstrate in vivo imaging capabilities, we incubate C. elegans with nanoparticles dispersed in buffer solution (5mg/mL concentration) and image forces involved in digestion using confocal microscopy. Our nanoparticles provide a platform for the first, non-genetically-encoded in vivo force sensors, and we describe routes to increase their sensitivity to the single-pN range.

An Anion-Induced Hydrothermal Oriented-Explosive Strategy for the Synthesis of Porous Upconversion Nanocrystals

PubMed Central

Qiu, Peiyu; Sun, Rongjin; Gao, Guo; Zhang, Chunlei; Chen, Bin; Yan, Naishun; Yin, Ting; Liu, Yanlei; Zhang, Jingjing; Yang, Yao; Cui, Daxiang

2015-01-01

Rare-earth (RE)-doped upconversion nanocrystals (UCNCs) are deemed as the promising candidates of luminescent nanoprobe for biological imaging and labeling. A number of methods have been used for the fabrication of UCNCs, but their assembly into porous architectures with desired size, shape and crystallographic phase remains a long-term challenging task. Here we report a facile, anion-induced hydrothermal oriented-explosive method to simultaneously control size, shape and phase of porous UCNCs. Our results confirmed the anion-induced hydrothermal oriented-explosion porous structure, size and phase transition for the cubic/hexagonal phase of NaLuF4 and NaGdF4 nanocrystals with various sizes and shapes. This general method is very important not only for successfully preparing lanthanide doped porous UCNCs, but also for clarifying the formation process of porous UCNCs in the hydrothermal system. The synthesized UCNCs were used for in vitro and in vivo CT imaging, and could be acted as the potential CT contrast agents. PMID:25767613

Design of an intelligent sub-50 nm nuclear-targeting nanotheranostic system for imaging guided intranuclear radiosensitization.

PubMed

Fan, Wenpei; Shen, Bo; Bu, Wenbo; Zheng, Xiangpeng; He, Qianjun; Cui, Zhaowen; Zhao, Kuaile; Zhang, Shengjian; Shi, Jianlin

2015-03-01

Clinically applied chemotherapy and radiotherapy is sometimes not effective due to the limited dose acting on DNA chains resident in the nuclei of cancerous cells. Herein, we develop a new theranostic technique of "intranuclear radiosensitization" aimed at directly damaging the DNA within the nucleus by a remarkable synergetic chemo-/radiotherapeutic effect based on intranuclear chemodrug-sensitized radiation enhancement. To achieve this goal, a sub-50 nm nuclear-targeting rattle-structured upconversion core/mesoporous silica nanotheranostic system was firstly constructed to directly transport the radiosensitizing drug Mitomycin C (MMC) into the nucleus for substantially enhanced synergetic chemo-/radiotherapy and simultaneous magnetic/upconversion luminescent (MR/UCL) bimodal imaging, which can lead to efficient cancer treatment as well as multi-drug resistance circumvention in vitro and in vivo . We hope the technique of intranuclear radiosensitization along with the design of nuclear-targeting nanotheranostics will contribute greatly to the development of cancer theranostics as well as to the improvement of the overall therapeutic effectiveness.

Genetically modified luminescent bacteria Ralostonia solanacerum, Pseudomonas syringae, Pseudomonas savastanoi, and wild type bacterium Vibrio fischeri in biosynthesis of gold nanoparticles from gold chloride trihydrate.

PubMed

Attaran, Neda; Eshghi, Hossein; Rahimizadeh, Mohammad; Mashreghi, Mansour; Bakavoli, Mehdi

2014-08-04

The effect of different genetically engineered bacteria, Pseudomonas syringae, Pseudomonas savastanoi, and Ralostonia solanacerum and also a natural marine bacterial species, Vibrio fischeri NRRL B-11177, is studied in producing gold nanoparticles. This is the first report about the biosynthesis of gold nanoparticles by natural and genetically engineered luminescent bacteria. These microorganisms reduced gold ions and produced fairly monodisperse nanoparticles. TEM analysis indicated that spherical nano gold particles in the different diameters and shapes were obtained at pH values of 6.64. In this biosynthesis protocol, the gold nanoparticles with desired shape and size can be prepared.

Effect of luminescence transport through adipose tissue on measurement of tissue temperature by using ZnCdS nanothermometers

NASA Astrophysics Data System (ADS)

Volkova, Elena K.; Yanina, Irina Yu.; Sagaydachnaya, Elena; Konyukhova, Julia G.; Kochubey, Vyacheslav I.; Tuchin, Valery V.

2018-02-01

The spectra of luminescence of ZnCdS nanoparticles (ZnCdS NPs) were measured and analyzed in a wide temperature range: from room to human body and further to a hyperthermic temperature resulting in tissue morphology change. The results show that the signal of luminescence of ZnCdS NPs placed within the tissue is reasonably good sensitive to temperature change and accompanied by phase transitions of lipid structures of adipose tissue. It is shown that the presence of a phase transition in adipose tissue upon its heating (polymorphic transformations of lipids) leads to a nonmonotonic temperature dependence of the intensity of luminescence for the nanoparticles introduced into adipose tissue. This is due to a change in the light scattering by the tissue. The light scattering of adipose tissue greatly distorts the results of temperature measurements. The application of these nanoparticles is possible for temperature measurements in very thin or weakly scattering samples.

X-ray micro-modulated luminescence tomography (XMLT)

PubMed Central

Cong, Wenxiang; Liu, Fenglin; Wang, Chao; Wang, Ge

2014-01-01

Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to strong scattering of light in a biological sample. X-ray microscopy can resolve spatial details of few microns deep inside a sample but contrast resolution is inadequate to depict heterogeneous features at cellular or sub-cellular levels. To enhance and enrich biological contrast at large imaging depth, various nanoparticles are introduced and become essential to basic research and molecular medicine. Nanoparticles can be functionalized as imaging probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+ nanoparticles were recently synthesized to facilitate luminescence energy storage with x-ray pre-excitation and subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we propose an x-ray micro-modulated luminescence tomography (XMLT, or MLT to be more general) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonstrate the feasibility of the proposed approach. PMID:24663898

Organosilylated complex [Eu(TTA)3(Bpy-Si)]: a bifunctional moiety for the engeneering of luminescent silica-based nanoparticles for bioimaging.

PubMed

Duarte, Adriana P; Mauline, Léïla; Gressier, Marie; Dexpert-Ghys, Jeannette; Roques, Christine; Caiut, José Maurício A; Deffune, Elenice; Maia, Danielle C G; Carlos, Iracilda Z; Ferreira, Antonio A P; Ribeiro, Sidney J L; Menu, Marie-Joëlle

2013-05-14

A new highly luminescent europium complex with the formula [Eu(TTA)3(Bpy-Si)], where TTA stands for the thenoyltrifluoroacetone, (C4H3S)COCH2COCF3, chelating ligand and Bpy-Si, Bpy-CH2NH(CH2)3Si(OEt)3, is an organosilyldipyridine ligand displaying a triethoxysilyl group as a grafting function has been synthesized and fully characterized. This bifunctional complex has been grafted onto the surface of dense silica nanoparticles (NPs) and on mesoporous silica microparticles as well. The covalent bonding of [Eu(TTA)3(Bpy-Si)] inside uniform Stöber silica nanoparticles was also achieved. The general methodology proposed could be applied to any silica matrix, allowed high grafting ratios that overcome chelate release and the tendency to agglomerate. Luminescent silica-based nanoparticles SiO2-[Eu(TTA)3(Bpy-Si)], with a diameter of 28 ± 2 nm, were successfully tested as a luminescent labels for the imaging of Pseudomonas aeruginosa biofilms. They were also functionalized by a specific monoclonal antibody and subsequently employed for the selective imaging of Escherichia coli bacteria.

Near Infrared-Emitting Cr3+/Eu3+ Co-doped Zinc Gallogermanate Persistence Luminescent Nanoparticles for Cell Imaging

NASA Astrophysics Data System (ADS)

Wang, Qiaoqiao; Zhang, Shuyun; Li, Zhiwei; Zhu, Qi

2018-02-01

Near infrared (NIR)-emitting persistent luminescent nanoparticles have been developed as potential agents for bioimaging. However, synthesizing uniform nanoparticles with long afterglow for long-term imaging is lacking. Here, we demonstrated the synthesis of spinel structured Zn3Ga2Ge2O10:Cr3+ (ZGGO:Cr3+) and Zn3Ga2Ge2O10:Cr3+,Eu3+ (ZGGO:Cr3+,Eu3+) nanoparticles by a sol-gel method in combination with a subsequent reducing atmosphere-free calcination. The samples were investigated via detailed characterizations by combined techniques of XRD, TEM, STEM, selected area electron diffraction, photoluminescence excitation (PLE)/photoluminescence (PL) spectroscopy, and temperature-dependent PL analysis. The single-crystalline nanoparticles are homogeneous solid solution, possessing uniform cubic shape and lateral size of 80-100 nm. Upon UV excitation at 273 nm, ZGGO:Cr3+,Eu3+ exhibited a NIR emission band at 697 nm (2E → 4A2 transition of distorted Cr3+ ions in gallogermanate), in the absence of Eu3+ emission. NIR persistent luminescence of the sample can last longer than 7200 s and still hold intense intensity. Eu3+ incorporation increased the persistent luminescence intensity and the afterglow time of ZGGO:Cr3+, but it did not significantly affect the thermal stability. The obtained ZGGO:Cr3+,Eu3+-NH2 nanoparticles possessed an excellent imaging capacity for cells in vitro.

Femtosecond excitation tuning and site energy memory of population transfer in poly(p-phenylenevinylene): Gated luminescence experiments and simulation

NASA Astrophysics Data System (ADS)

Sperling, J.; Milota, F.; Tortschanoff, A.; Warmuth, Ch.; Mollay, B.; Bässler, H.; Kauffmann, H. F.

2002-12-01

We present a comprehensive experimental and computational study on fs-relaxational dynamics of optical excitations in the conjugated polymer poly(p-phenylenevinylene) (PPV) under selective excitation tuning conditions into the long-wavelength, low-vibrational S1ν=0-density-of-states (DOS). The dependence of single-wavelength luminescence kinetics and time-windowed spectral transients on distinct, initial excitation boundaries at 1.4 K and at room temperature was measured applying the luminescence up-conversion technique. The typical energy-dispersive intra-DOS energy transfer was simulated by a combination of static Monte Carlo method with a dynamical algorithm for solving the energy-space transport Master-Equation in population-space. For various, selective excitations that give rise to specific S1-population distributions in distinct spatial and energetic subspaces inside the DOS, simulations confirm the experimental results and show that the subsequent, energy-dissipative, multilevel relaxation is hierarchically constrained, and reveals a pronounced site-energy memory effect with a migration-threshold, characteristic of the (dressed) excitation dynamics in the disordered PPV many-body system.

Imaging of Biological Cells Using Luminescent Silver Nanoparticles

NASA Astrophysics Data System (ADS)

Kravets, Vira; Almemar, Zamavang; Jiang, Ke; Culhane, Kyle; Machado, Rosa; Hagen, Guy; Kotko, Andriy; Dmytruk, Igor; Spendier, Kathrin; Pinchuk, Anatoliy

2016-01-01

The application of luminescent silver nanoparticles as imaging agents for neural stem and rat basophilic leukemia cells was demonstrated. The experimental size dependence of the extinction and emission spectra for silver nanoparticles were also studied. The nanoparticles were functionalized with fluorescent glycine dimers. Spectral position of the resonance extinction and photoluminescence emission for particles with average diameters ranging from 9 to 32 nm were examined. As the particle size increased, the spectral peaks for both extinction and the intrinsic emission of silver nanoparticles shifted to the red end of the spectrum. The intrinsic photoluminescence of the particles was orders of magnitude weaker and was spectrally separated from the photoluminescence of the glycine dimer ligands. The spectral position of the ligand emission was independent of the particle size; however, the quantum yield of the nanoparticle-ligand system was size-dependent. This was attributed to the enhancement of the ligand's emission caused by the local electric field strength's dependence on the particle size. The maximum quantum yield determined for the nanoparticle-ligand complex was (5.2 ± 0.1) %. The nanoparticles were able to penetrate cell membranes of rat basophilic leukemia and neural stem cells fixed with paraformaldehyde. Additionally, toxicity studies were performed. It was found that towards rat basophilic leukemia cells, luminescent silver nanoparticles had a toxic effect in the silver atom concentration range of 10-100 μM.

Fabrication and Characterization of Luminescent Magnetic Bifunctional Nanocomposite Based on TbPO4·H2O Nanowires and Fe3O4 Nanoparticles

NASA Astrophysics Data System (ADS)

Huong, Nguyen Thanh; Hung, Nguyen Manh; Lien, Pham Thi; Van, Nguyen Duc; Nam, Pham Hong; Binh, Nguyen Thanh; Minh, Le Quoc

2016-07-01

The fabrication and properties of luminescent magnetic bifunctional nanocomposites comprised of TbPO4·H2O nanowires as a core and magnetite nanoparticles as a shell are presented. TbPO4·H2O nanowires were synthesized by a microwave-assisted method while the grafting process of freshly-formed superparamagnetic magnetite nanoparticles on the surface of luminescent nanowires was carried out by a co-precipitate method. The effects of the Fe3O4/TbPO4·H2O mass ratio on the luminescent and magnetic properties of the obtained nanocomposite were also investigated. The results showed that, for the optimized bifunctional nanocomposites, green luminescent emissions at 488 nm, 542 nm, 585 nm, 620 nm and superparamagnetic behavior with saturation magnetization M s of 6 emu/g were achieved. With a hyperthermia temperature of ~43.5°C under an alternating current (AC) magnetic field, the obtained TbPO4·H2O/Fe3O4 nanocomposite was expected to be used for both optical probing and hyperthermia cancer treatments in biomedical applications.

Controlled fabrication of luminescent and magnetic nanocomposites

NASA Astrophysics Data System (ADS)

Ma, Yingxin; Zhong, Yucheng; Fan, Jing; Huang, Weiren

2018-03-01

Luminescent and magnetic multifunctional nanocomposite is in high demand and widely used in many scales, such as drug delivery, bioseparation, chemical/biosensors, and so on. Although lots of strategies have been successfully developed for the demand of multifunctional nanocomposites, it is not easy to prepare multifunctional nanocomposites by using a simple method, and satisfy all kinds of demands simultaneously. In this work, via a facile and versatile method, luminescent nanocrystals and magnetic nanoparticles were successfully synthesized through self-assembly under vigorous stirring and ultrasonic treatment. These multifunctional nanocomposites are not only water stable but also find wide application such as magnetic separation and concentration with a series of moderate speed, multicolor fluorescence at different emission wavelength, high efficiency of the excitation and emission, and so on. By changing different kinds of luminescent nanocrystals and controlling the amount of luminescent and magnetic nanoparticles, a train of multifunctional nanocomposites was successfully fabricated via a versatile and robust method.

Spectral management and morphology evolution of β-NaGdF4:Yb3+,Er3+ by tuning the concentration of citric acid

NASA Astrophysics Data System (ADS)

Yao, Lu; Xu, Dekang; Lin, Hao; Yang, Shenghong; Zhang, Yueli

2018-05-01

β-NaGdF4:Yb3+,Er3+ upconversion (UC) particles were prepared by a facile hydrothermal process with assistance of citric acid (CA). The morphologies of β-NaGdF4 UC particles were controlled by changing the doses of CA in precursor. With an increase CA concentration in precursor, increase sizes of crystals were observed, resulting in the increasing of luminescence intensity. The energy transfer ET mechanism was analyzed in detail.

Seeing the invisible plasma with transient phonons in cuprous oxide

DOE PAGES

Frazer, Laszlo; Schaller, Richard D.; Chang, Kelvin B.; ...

2016-12-12

Here, the emission of phonons from electron–hole plasma is the primary limit on the efficiency of photovoltaic devices operating above the bandgap. In cuprous oxide (Cu 2O) there is no luminescence from electron–hole plasma. Therefore, we searched for optical phonons emitted by energetic charge carriers using phonon-to-exciton upconversion transitions. We found 14 meV phonons with a lifetime of 0.916 ± 0.008 ps and 79 meV phonons that are longer lived and overrepresented. It is surprising that the higher energy phonon has a longer lifetime.

Tuning from green to red the upconversion emission of Y2O3:Er3+-Yb3+ nanophosphors

NASA Astrophysics Data System (ADS)

Diaz-Torres, L. A.; Salas, P.; Oliva, J.; Resendiz-L, E.; Rodriguez-Gonzalez, C.; Meza, O.

2017-01-01

In this work, the structural, morphological and luminescent properties of Y2O3 nanophosphors doped with Er3+ (1 mol%) and different Yb3+ concentrations (2-12 mol%) have been studied. Those nanophosphors were synthesized using a simple hydrothermal method. XRD analysis indicates that all the samples presented a pure cubic phase even for Yb concentrations as high as 12 mol%. In addition, SEM images show nanoparticles with quasi-spherical shapes with average sizes in the range of 300-340 nm. Photoluminescence measurements obtained after excitation at 967 nm revealed that our samples have strong green (563 nm) and red emissions (660 nm) corresponding to 2H11/2 + 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions, respectively. We also observed that the green band is quenched and the red emission enhanced as the Yb concentration increases. In consequence, the CIE coordinates changed from (0.35, 0.64) in the green region to (0.59, 0.39) in the red region. Thus, the tuning properties of Y2O3 nanophosphors suggest that they are good candidates for applications in lighting.

A Post-synthetic Modification of II–VI Nanoparticles to Create Tb3+ and Eu3+ Luminophores

PubMed Central

Mukherjee, Prasun; Sloan, Robin F.; Shade, Chad M.; Waldeck, David H.; Petoud, Stéphane

2013-01-01

We describe a novel method for creating luminescent lanthanide-containing nanoparticles in which the lanthanide cations are sensitized by the semiconductor nanoparticle’s electronic excitation. In contrast to previous strategies, this new approach creates such materials by addition of external salt to a solution of fully formed nanoparticles. We demonstrate this post-synthetic modification for the lanthanide luminescence sensitization of two visible emitting lanthanides (Ln), Tb3+ and Eu3+ ions, through ZnS nanoparticles in which the cations were added post-synthetically as external Ln(NO3)3·xH2O salt to solutions of ZnS nanoparticles. The post-synthetically treated ZnS nanoparticle systems display Tb3+ and Eu3+ luminescence intensities that are comparable to those of doped Zn(Ln)S nanoparticles, which we reported previously (J. Phys. Chem. A, 2011, 115, 4031–4041). A comparison with the synthetically doped systems is used to contrast the spatial distribution of the lanthanide ions, bulk versus surface localized. The post-synthetic strategy described in this work is fundamentally different from the synthetic incorporation (doping) approach and offers a rapid and less synthetically demanding protocol for Tb3+:ZnS and Eu3+:ZnS luminophores, thereby facilitating their use in a broad range of applications. PMID:23997842

Nanoscale coordination polymers exhibiting luminescence properties and NMR relaxivity

NASA Astrophysics Data System (ADS)

Chelebaeva, Elena; Larionova, Joulia; Guari, Yannick; Ferreira, Rute A. S.; Carlos, Luis D.; Trifonov, Alexander A.; Kalaivani, Thangavel; Lascialfari, Alessandro; Guérin, Christian; Molvinger, Karine; Datas, Lucien; Maynadier, Marie; Gary-Bobo, Magali; Garcia, Marcel

2011-03-01

This article presents the first example of ultra-small (3-4 nm) magneto-luminescent cyano-bridged coordination polymer nanoparticles Ln0.333+Gdx3+/[Mo(CN)8]3- (Ln = Eu (x = 0.34), Tb (x = 0.35)) enwrapped by a natural biocompatible polymer chitosan. The aqueous colloidal solutions of these nanoparticles present a luminescence characteristic of the corresponding lanthanides (5D0 --> 7F0-4 (Eu3+) or the 5D4 --> 7F6-2 (Tb3+)) under UV excitation and a green luminescence of the chitosan shell under excitation in the visible region. Magnetic Resonance Imaging (MRI) efficiency, i.e. the nuclear relaxivity, measurements performed for Ln0.333+Gdx3+/[Mo(CN)8]3- nanoparticles show r1p and r2p relaxivities slightly higher than or comparable to the ones of the commercial paramagnetic compounds Gd-DTPA® or Omniscan® indicating that our samples may potentially be considered as a positive contrast agent for MRI. The in vitro studies performed on these nanoparticles show that they maybe internalized into human cancer and normal cells and well detected by fluorescence at the single cell level. They present high stability even at low pH and lack of cytotoxicity both in human cancer and normal cells.This article presents the first example of ultra-small (3-4 nm) magneto-luminescent cyano-bridged coordination polymer nanoparticles Ln0.333+Gdx3+/[Mo(CN)8]3- (Ln = Eu (x = 0.34), Tb (x = 0.35)) enwrapped by a natural biocompatible polymer chitosan. The aqueous colloidal solutions of these nanoparticles present a luminescence characteristic of the corresponding lanthanides (5D0 --> 7F0-4 (Eu3+) or the 5D4 --> 7F6-2 (Tb3+)) under UV excitation and a green luminescence of the chitosan shell under excitation in the visible region. Magnetic Resonance Imaging (MRI) efficiency, i.e. the nuclear relaxivity, measurements performed for Ln0.333+Gdx3+/[Mo(CN)8]3- nanoparticles show r1p and r2p relaxivities slightly higher than or comparable to the ones of the commercial paramagnetic compounds Gd-DTPA® or Omniscan® indicating that our samples may potentially be considered as a positive contrast agent for MRI. The in vitro studies performed on these nanoparticles show that they maybe internalized into human cancer and normal cells and well detected by fluorescence at the single cell level. They present high stability even at low pH and lack of cytotoxicity both in human cancer and normal cells. Electronic supplementary information (ESI) available: TEM images and size distribution histograms, IR and emission spectra, diffraction pattern and HRTEM coupled EDX analysis. See DOI: 10.1039/c0nr00709a

Red, green, and blue luminescence by carbon dots: full-color emission tuning and multicolor cellular imaging.

PubMed

Jiang, Kai; Sun, Shan; Zhang, Ling; Lu, Yue; Wu, Aiguo; Cai, Congzhong; Lin, Hengwei

2015-04-27

A facile approach for preparation of photoluminescent (PL) carbon dots (CDs) is reported. The three resulting CDs emit bright and stable red, green and blue (RGB) colors of luminescence, under a single ultraviolet-light excitation. Alterations of PL emission of these CDs are tentatively proposed to result from the difference in their particle size and nitrogen content. Interestingly, up-conversion (UC)PL of these CDs is also observed. Moreover, flexible full-color emissive PVA films can be achieved through mixing two or three CDs in the appropriate ratios. These CDs also show low cytotoxicity and excellent cellular imaging capability. The facile preparation and unique optical features make these CDs potentially useful in numerous applications such as light-emitting diodes, full-color displays, and multiplexed (UC)PL bioimaging. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectral engineering of LaF3:Ce3+ nanoparticles: The role of Ce3+ in surface sites

NASA Astrophysics Data System (ADS)

Jacobsohn, L. G.; Toncelli, A.; Sprinkle, K. B.; Kucera, C. J.; Ballato, J.

2012-04-01

Due to the high surface-to-volume ratio, luminescence centers on the surface have relative dominance in the overall spectral response of nanoparticles. The luminescence of LaF3:Ce3+ nanoparticles was investigated in the spectral and temporal domains with a particular focus on the role of Ce3+ on the surface. These nanoparticles present two luminescence bands at 4.10 eV and 4.37 eV attributed to Ce3+ transitions from the 5d level to the spin-orbit split 4f ground levels 2F5/2 and 2F7/2, in addition to a low-energy band at 3.62 eV that has been attributed to Ce3+ ions residing in perturbed sites. The growth of up to three undoped shells, ca. 0.9 nm thick each, around the core promoted a progressive enhancement of luminescence output, concomitant with an increase in the fluorescence lifetime due to the weakening of energy transfer through multipolar interaction between Ce3+ in the core and quenching defects on the surface. Also, the growth of the first shell led to a decrease in the relative intensity of the low-energy band and a 0.23 eV shift to higher energies. These results were interpreted as being due to the existence of two types of perturbed sites, one on the surface that is eliminated by the growth of the first shell, and another within the volume of the nanoparticle, similar to observations in bulk single crystals. This work demonstrates how surface engineering can affect and control the luminescence behavior of this nanomaterial.

Terbium content affects the luminescence properties of ZrO2:Tb nanoparticles for mammary cancer imaging in mice

NASA Astrophysics Data System (ADS)

Kaszewski, Jarosław; Borgstrom, Emanuel; Witkowski, Bartłomiej S.; Wachnicki, Łukasz; Kiełbik, Paula; Slonska, Anna; Domino, Malgorzata A.; Narkiewicz, Urszula; Gajewski, Zdzislaw; Hochepied, Jean-François; Godlewski, Michał M.; Godlewski, Marek

2017-12-01

The use of nanoparticles in medicine is a rapidly growing research field with numerous potential applications, especially in the field of cancer diagnosis and therapy. Nanoparticles can be intrinsically diagnostic of therapeutic, or they can be conjugated with diagnostic or therapeutic compounds. Nanoparticles may also passively or actively target tumor cells specifically using the enhanced permeation and retention (EPR) effect, or the addition of targeting ligands to their surface. This may provide a diagnostic or/and therapeutic tools to target primary as well as metastatic tumors. The transport, distribution and toxicity of nanoparticles depends greatly on their size and composition, thus every new formulation needs to be extensively researched. This work was focused on the development of Tb-doped ZrO2 nanoparticles (NPs) for application in cancer imaging. Obtained nanoparticles were below 10 nm with very low influence of Tb concentration on size. Terbium stabilization of ZrO2 had influence on the luminescence properties of obtained material. Partially stabilized zirconium dioxide exhibited broad host related emission peaking at 500 nm, disappearing with the terbium content. We confirmed alimentary absorption and wide distribution of luminescent ZrO2:Tb nanoparticles in mice with their gradual accumulation in the experimentally induced mammary cancers. Furthermore, a high concentration of NPs was found within the lung metastases as opposed to healthy lung tissue, where no NPs-related signal was observed.

Magnetically encoded luminescent composite nanoparticles through layer-by-layer self-assembly.

PubMed

Song, Erqun; Han, Weiye; Xu, Hongyan; Jiang, Yunfei; Cheng, Dan; Song, Yang; Swihart, Mark T

2014-11-03

Sensitive and rapid detection of multiple analytes and the collection of components from complex samples are important in fields ranging from bioassays/chemical assays, clinical diagnosis, to environmental monitoring. A convenient strategy for creating magnetically encoded luminescent CdTe@SiO2 @n Fe3 O4 composite nanoparticles, by using a layer-by-layer self-assembly approach based on electrostatic interactions, is described. Silica-coated CdTe quantum dots (CdTe@SiO2 ) serve as core templates for the deposition of alternating layers of Fe3 O4 magnetic nanoparticles and poly(dimethyldiallyl ammonium chloride), to construct CdTe@SiO2 @n Fe3 O4 (n=1, 2, 3, …︁) composite nanoparticles with a defined number (n) of Fe3 O4 layers. Composite nanoparticles were characterized by zeta-potential analysis, fluorescence spectroscopy, vibrating sample magnetometry, and transmission electron microscopy, which showed that the CdTe@SiO2 @n Fe3 O4 composite nanoparticles exhibited excellent luminescence properties coupled with well-defined magnetic responses. To demonstrate the utility of these magnetically encoded nanoparticles for near-simultaneous detection and separation of multiple components from complex samples, three different fluorescently labeled IgG proteins, as model targets, were identified and collected from a mixture by using the CdTe@SiO2 @n Fe3 O4 nanoparticles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of an optically-based tension-indicating implanted orthopedic screw with a luminescent spectral ruler

NASA Astrophysics Data System (ADS)

Ravikumar, Nakul; Rogalski, Melissa M.; Benza, Donny; Lake, Joshua; Urban, Matthew; Pelham, Hunter; Anker, Jeffrey N.; DesJardins, John D.

2017-03-01

An orthopaedic screw was designed with an optical tension-indicator to non-invasively quantify screw tension and monitor the load sharing between the bone and the implant. The screw both applies load to the bone, and measures this load by reporting the strain on the screw. The screw contains a colorimetric optical encoder that converts axial strain into colorimetric changes visible through the head of the screw, or luminescent spectral changes that are detected through tissue. Screws were tested under cyclic mechanical loading to mimic in-vivo conditions to verify the sensitivity, repeatability, and reproducibility of the sensor. In the absence to tissue, color was measured using a digital camera as a function of axial load on a stainless steel cannulated (hollow) orthopedic screw, modified by adding a passive colorimetric strain gauge through the central hole. The sensor was able to quantify clinically-relevant bone healing strains. The sensor exhibited good repeatability and reproducibility but also displayed hysteresis due to the internal mechanics of the screw. The strain indicator was also modified for measurement through tissue by replacing the reflective colorimetric sensor with a low-background X-ray excited optical luminescence signal. Luminescent spectra were acquired through 6 mm of chicken breast tissue. Overall, this research shows feasibility for a unique device which quantifies the strain on an orthopedic screw. Future research will involve reducing hysteresis by changing the mechanism of strain transduction in the screw, miniaturizing the luminescent strain gauge, monitoring bending as well as tension, using alternative luminescent spectral rulers based upon near infrared fluorescence or upconversion luminescence, and application to monitoring changes in pretension and load sharing during bone healing.

Nd3+/Yb3+ cascade-sensitized single-band red upconversion emission in active-core/active-shell nanocrystals.

PubMed

Ding, M Y; Hou, J J; Yuan, Y J; Bai, W F; Lu, C H; Xi, J H; Ji, Z G; Chen, D Q

2018-08-24

Lanthanide-doped upconversion nanomaterials (UCNMs) have promoted extensive interest for its biological research and biomedical applications, benefiting from low autofluorescence background, deep light penetration depth, and minimal photo-damage to biological tissues. However, owing to the 980 nm laser-induced overheating issue and the attenuation effect associated with conventional multi-peak emissions, the usage of UCNMs as fluorescent bioprobes is still limited. To address these issues, an effective strategy has been proposed to tune both the excitation and emission peaks of UCNMs into the first biological window (650 ∼ 900 nm), where the light absorption by water and hemoglobin in biological tissues is minimal. Based on the Nd 3+ /Yb 3+ cascade-sensitized upconversion process and efficient exchange-energy transfer between Mn 2+ and Er 3+ in conjunction with the active-core@active-shell nanostructured design, we have developed a new class of upconversion nanoparticles (UCNPs) that exhibit strong single-band red emission upon excitation of an 808 nm near-infrared laser. Hopefully, the well-designed KMnF 3 :Yb/Er/Nd@ KMnF 3 :Yb/Nd core-shell nanocrystals will be considered a promising alternative to conventionally used UCNPs for biolabeling applications without the concern of the overheating issue and the attenuation constraints.

Synthesis of improved upconversion nanoparticles as ultrasensitive fluorescence probe for mycotoxins.

PubMed

Chen, Quansheng; Hu, Weiwei; Sun, Cuicui; Li, Huanhuan; Ouyang, Qin

2016-09-28

Rare earth-doped upconversion nanoparticles (UCNPs) have promising potentials in biodetection due to their unique frequency upconverting capability and high detection sensitivity. This paper reports an improved UCNPs-based fluorescence probe for dual-sensing of Aflatoxin B1 (AFB1) and Deoxynivalenol (DON) using a magnetism-induced separation and the specific formation of antibody-targets complex. Herein, the improved UCNPs, which were namely NaYF4:Yb/Ho/Gd and NaYF4:Yb/Tm/Gd, were systematically studied based on the optimization of reaction time, temperature and the concentration of dopant ions with simultaneous phase and size controlled NaYF4 nanoparticles; and the targets were detected using the pattern of competitive combination assay. Under an optimized condition, the advanced fluorescent probes revealed stronger fluorescent properties, broader biological applications and better storage stabilities compared to traditional UCNPs-based ones; and ultrasensitive determinations of AFB1 and DON were achieved under a wide sensing range of 0.001-0.1 ng ml(-1) with the limit of detection (LOD) of 0.001 ng ml(-1). Additionally, the applicability of the improved nanosensor for the detection of mycotoxins was also confirmed in adulterated oil samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Core - shell upconversion nanoparticle - semiconductor heterostructures for photodynamic therapy

NASA Astrophysics Data System (ADS)

Dou, Qing Qing; Rengaramchandran, Adith; Selvan, Subramanian Tamil; Paulmurugan, Ramasamy; Zhang, Yong

2015-02-01

Core-shell nanoparticles (CSNPs) with diverse chemical compositions have been attracting greater attention in recent years. However, it has been a challenge to develop CSNPs with different crystal structures due to the lattice mismatch of the nanocrystals. Here we report a rational design of core-shell heterostructure consisting of NaYF4:Yb,Tm upconversion nanoparticle (UCN) as the core and ZnO semiconductor as the shell for potential application in photodynamic therapy (PDT). The core-shell architecture (confirmed by TEM and STEM) enables for improving the loading efficiency of photosensitizer (ZnO) as the semiconductor is directly coated on the UCN core. Importantly, UCN acts as a transducer to sensitize ZnO and trigger the generation of cytotoxic reactive oxygen species (ROS) to induce cancer cell death. We also present a firefly luciferase (FLuc) reporter gene based molecular biosensor (ARE-FLuc) to measure the antioxidant signaling response activated in cells during the release of ROS in response to the exposure of CSNPs under 980 nm NIR light. The breast cancer cells (MDA-MB-231 and 4T1) exposed to CSNPs showed significant release of ROS as measured by aminophenyl fluorescein (APF) and ARE-FLuc luciferase assays, and ~45% cancer cell death as measured by MTT assay, when illuminated with 980 nm NIR light.

Photoluminescence of magnesium-associated color centers in LiF crystals implanted with magnesium ions

NASA Astrophysics Data System (ADS)

Nebogin, S. A.; Ivanov, N. A.; Bryukvina, L. I.; V. Shipitsin, N.; E. Rzhechitskii, A.; Papernyi, V. L.

2018-05-01

In the present paper, the effect of magnesium nanoparticles implanted in a LiF crystal on the optical properties of color centers is studied. The transmittance spectra and AFM images demonstrate effective formation of the color centers and magnesium nanoparticles in an implanted layer of ∼ 60-100 nm in thickness. Under thermal annealing, a periodical structure is formed on the surface of the crystal and in the implanted layer due to self-organization of the magnesium nanoparticles. Upon excitation by argon laser with a wavelength of 488 nm at 5 K, in a LiF crystal, implanted with magnesium ions as well as in heavily γ-irradiated LiF: Mg crystals, luminescence of the color centers at λmax = 640 nm with a zero-phonon line at 601.5 nm is observed. The interaction of magnesium nanoparticles and luminescing color centers in a layer implanted with magnesium ions has been revealed. It is shown that the luminescence intensity of the implanted layer at a wavelength of 640 nm is by more than two thousand times higher than that of a heavily γ-irradiated LiF: Mg crystal. The broadening of the zero-phonon line at 601.5 nm in the spectrum of the implanted layer indicates the interaction of the emitting quantum system with local field of the surface plasmons of magnesium nanoparticles. The focus of this work is to further optimize the processing parameters in a way to result in luminescence great enhancement of color centers by magnesium nanoparticles in LiF.

Quantitative and discriminative analysis of nucleic acid samples using luminometric nonspecific nanoparticle methods

NASA Astrophysics Data System (ADS)

Pihlasalo, S.; Mariani, L.; Härmä, H.

2016-03-01

Homogeneous simple assays utilizing luminescence quenching and time-resolved luminescence resonance energy transfer (TR-LRET) were developed for the quantification of nucleic acids without sequence information. Nucleic acids prevent the adsorption of a protein to europium nanoparticles which is detected as a luminescence quenching of europium nanoparticles with a soluble quencher or as a decrease of TR-LRET from europium nanoparticles to the acceptor dye. Contrary to the existing methods based on fluorescent dye binding to nucleic acids, equal sensitivities for both single- (ssDNA) and double-stranded DNA (dsDNA) were measured and a detection limit of 60 pg was calculated for the quenching assay. The average coefficient of variation was 5% for the quenching assay and 8% for the TR-LRET assay. The TR-LRET assay was also combined with a nucleic acid dye selective to dsDNA in a single tube assay to measure the total concentration of DNA and the ratio of ssDNA and dsDNA in the mixture. To our knowledge, such a multiplexed assay is not accomplished with commercially available assays.Homogeneous simple assays utilizing luminescence quenching and time-resolved luminescence resonance energy transfer (TR-LRET) were developed for the quantification of nucleic acids without sequence information. Nucleic acids prevent the adsorption of a protein to europium nanoparticles which is detected as a luminescence quenching of europium nanoparticles with a soluble quencher or as a decrease of TR-LRET from europium nanoparticles to the acceptor dye. Contrary to the existing methods based on fluorescent dye binding to nucleic acids, equal sensitivities for both single- (ssDNA) and double-stranded DNA (dsDNA) were measured and a detection limit of 60 pg was calculated for the quenching assay. The average coefficient of variation was 5% for the quenching assay and 8% for the TR-LRET assay. The TR-LRET assay was also combined with a nucleic acid dye selective to dsDNA in a single tube assay to measure the total concentration of DNA and the ratio of ssDNA and dsDNA in the mixture. To our knowledge, such a multiplexed assay is not accomplished with commercially available assays. Electronic supplementary information (ESI) available: The labeling of amino modified polystyrene nanoparticles with Eu3+ chelate and the experimental details and results for the optimization of nucleic acid binding protein and for the ratiometric measurement of DNA and RNA with quenching assay. See DOI: 10.1039/c5nr09252c

Synthesis, characterization, and cytotoxicity in human erythrocytes of multifunctional, magnetic, and luminescent nanocrystalline rare earth fluorides

NASA Astrophysics Data System (ADS)

Grzyb, Tomasz; Mrówczyńska, Lucyna; Szczeszak, Agata; Śniadecki, Zbigniew; Runowski, Marcin; Idzikowski, Bogdan; Lis, Stefan

2015-10-01

Multifunctional nanoparticles exhibiting red or green luminescence properties and magnetism were synthesized and thoroughly analyzed. The hydrothermal method was used for the synthesis of Eu3+- or Tb3+-doped GdF3-, NaGdF4-, and BaGdF5-based nanocrystalline materials. The X-ray diffraction patterns of the samples confirmed the desired compositions of the materials. Transmission electron microscope images revealed the different morphologies of the products, including the nanocrystal sizes, which varied from 12 nm in the case of BaGdF5-based nanoparticles to larger structures with dimensions exceeding 300 nm. All of the samples presented luminescence under ultraviolet irradiation, as well as when the samples were in the form of water colloids. The highest luminescence was observed for BaGdF5-based materials. The obtained nanoparticles exhibited paramagnetism along with probable evidence of superparamagnetic behavior at low temperatures. The particles' magnetic characteristics were also preserved for samples in the form of a suspension in distilled water. The cytotoxicity studies against the human erythrocytes indicated that the synthesized nanoparticles are non-toxic because they did not cause the red blood cells shape changes nor did they alter their membrane structure and permeabilization.

Facile synthesis and luminescent properties of TiO{sub 2}:Eu{sup 3+} nanorods and spindle-shaped nanoparticles from titanate nanotubes precursors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hongbo; Sheng, Ye; Zhao, Huan

2012-12-15

Graphical abstract: This picture illustration for the formation process of TiO{sub 2}:Eu{sup 3+} nanorods and spindle-shaped nanoparticles. Display Omitted Highlights: ► TiO{sub 2}:Eu{sup 3+} nanorods and spindle-shaped nanoparticles were prepared. ► The nanotubes could transform to nanorods and spindle-shaped nanoparticles. ► The luminescence properties are dependent on the increases of the bandgap. -- Abstract: TiO{sub 2}:Eu{sup 3+} nanorods and spindle-shaped nanoparticles have been successfully prepared through simple calcination and hydrothermal process respectively using titanate as the precursors. On the basis of X-ray diffraction results, the as-obtained precursors are titanate (H{sub 2}Ti{sub 2}O{sub 5}·H{sub 2}O), while nanorods and spindle-shaped nanoparticles aremore » pure anatase phase of TiO{sub 2}. TEM and SEM images show that the as-formed precursor could be transformed from nanotubes into nanorods and spindle-shaped nanoparticles by the calcination and hydrothermal process respectively. Under UV light excitation, both the TiO{sub 2}:Eu{sup 3+} nanorods and spindle-shaped nanoparticles exhibit the strong red emission. In addition, the luminescence intensity of TiO{sub 2}:Eu{sup 3+} nanorods is higher than that of TiO{sub 2}:Eu{sup 3+} spindle-shaped nanoparticles due to the increases of the bandgap of the TiO{sub 2} nanorods.« less

Visualization of upconverting nanoparticles in strongly scattering media

PubMed Central

Khaydukov, E. V.; Semchishen, V. A.; Seminogov, V. N.; Nechaev, A. V.; Zvyagin, A. V.; Sokolov, V. I.; Akhmanov, A. S.; Panchenko, V. Ya.

2014-01-01

Optical visualization systems are needed in medical applications for determining the localization of deep-seated luminescent markers in biotissues. The spatial resolution of such systems is limited by the scattering of the tissues. We present a novel epi-luminescent technique, which allows a 1.8-fold increase in the lateral spatial resolution in determining the localization of markers lying deep in a scattering medium compared to the traditional visualization techniques. This goal is attained by using NaYF4:Yb3+Tm3+@NaYF4 core/shell nanoparticles and special optical fiber probe with combined channels for the excitation and detection of anti-Stokes luminescence signals. PMID:24940552

Persistent luminescence of transition metal (Co, Ni...)-doped ZnGa2O4 phosphors for applications in the near-infrared range

NASA Astrophysics Data System (ADS)

Pellerin, Morgane; Castaing, Victor; Gourier, Didier; Chanéac, Corinne; Viana, Bruno

2018-02-01

Persistent luminescence materials present many applications including security lighting and bio-imaging. Many progresses have been made in the elaboration of persistent luminescent nanoparticles suitable for the first NIR partial transparency window (650 - 950 nm). Moving to the second and third near-infrared partial transparency windows (1000 nm - 1800 nm) allows further reducing of scattering, absorption and tissue autofluorescence effects. In this work, we present the synthesis of Co2+ and Ni2+ doped zinc-gallate nanoparticles with broad emission covering the NIR-II range. Site occupancy, energy levels, optical features and persistent phenomena are presented.

Surface-functionalized nanoparticles for biosensing and imaging-guided therapeutics

NASA Astrophysics Data System (ADS)

Jiang, Shan; Win, Khin Yin; Liu, Shuhua; Teng, Choon Peng; Zheng, Yuangang; Han, Ming-Yong

2013-03-01

In this article, the very recent progress of various functional inorganic nanomaterials is reviewed including their unique properties, surface functionalization strategies, and applications in biosensing and imaging-guided therapeutics. The proper surface functionalization renders them with stability, biocompatibility and functionality in physiological environments, and further enables their targeted use in bioapplications after bioconjugation via selective and specific recognition. The surface-functionalized nanoprobes using the most actively studied nanoparticles (i.e., gold nanoparticles, quantum dots, upconversion nanoparticles, and magnetic nanoparticles) make them an excellent platform for a wide range of bioapplications. With more efforts in recent years, they have been widely developed as labeling probes to detect various biological species such as proteins, nucleic acids and ions, and extensively employed as imaging probes to guide therapeutics such as drug/gene delivery and photothermal/photodynamic therapy.

Formation of Ag nanoparticles and enhancement of Tb3+ luminescence in Tb and Ag co-doped lithium-lanthanum-aluminosilicate glass

NASA Astrophysics Data System (ADS)

Piasecki, Patryk; Piasecki, Ashley; Pan, Zhengda; Mu, Richard; Morgan, Steven H.

2010-12-01

Tb3+ and Ag co-doped glass nano-composites were synthesized in a glass matrix Li2O-LaF3-Al2O3-SiO2 (LLAS) by a melt-quench technique. The growth of Ag nanoparticles (NPs) was controlled by a thermal annealing process. A broad absorption band peaking at about 420 nm was observed due to surface plasmon resonance (SPR) of Ag NPs. The intensity of this band grows with increasing annealing time. The transmission electron microscopic image (TEM) reveals the formation of Ag NPs in glass matrix. Photoluminescence (PL) emission and excitation spectra were measured for glass samples with different Ag concentrations and different annealing times. Plasmon enhanced Tb3+ luminescence was observed at certain excitation wavelength regions. Luminescence quenching was also observed for samples with high Ag concentration and longer annealing time. Our luminescence results suggest that there are two competitive effects, enhancement and quenching, acting on Tb3+ luminescence in the presence of Ag NPs. The enhancement of Tb3+ luminescence is mainly attributed to local field effects due to SPR. The quenching of luminescence suggests an energy transfer from Tb3+ ions to Ag NPs.

[Preparation and photoluminescence study of Er3+ : Y2O3 transparent ceramics].

PubMed

Luo, Jun-ming; Li, Yong-xiu; Deng, Li-ping

2008-10-01

Y2O3 acted as the matrix material, which was doped with different concentrations of Er3+, Er3+ : Y2O3 nanocrystalline powder was prepared by co-precipitation method, and Er3+ : Y2O3 transparent ceramics was fabricated by vacuum sintering at 1700 degrees C, 1 x 10(-3) Pa for 8 h. By using the X-ray diffraction (D/MAX-RB), transmission electron microscopy(Philips EM420), automatic logging spectrophotometer(DMR-22), fluorescence analyzer (F-4500) and 980 nm diode laser, the structural, morphological and luminescence properties of the sample were investigated. The results show that Er3+ dissolved completely in the Y2O3 cubic phase, the precursor was amorphous, weak diffraction peaks appeared after calcination at 400 degrees C, and if calcined at 700 degrees C, the precursor turned to pure cubic phase. With increasing the calcining temperature, the diffraction peaks became sharp quickly, and when the calcining temperature reached 1100 degrees C, the diffraction peaks became very sharp, indicating that the grains were very large. The particles of Er+ : Y2O3 is homogeneous and nearly spherical, the average diameter of the particles is in the range of 40-60 nm after being calcined at 1000 degrees C for 2 h. The relative density of Er3+ : Y2O3 transparent ceramics is 99.8%, the transmittance of the Er2+ : Y2O3 transparent ceramics is markedly lower than the single crystal at the short wavelength, but the transmittance is improved noticeably with increasing the wavelength, and the transmittance exceeds 60% at the wavelength of 1200 nm. Excited under the 980 nm diode laser, there are two main up-conversion emission bands, green emission centers at 562 nm and red emission centers at 660 nm, which correspond to (4)S(3/2) / (2)H(11/2) - (4)I(15/2) and (4)F(9/2) - (4)I(15/2) radiative transitions respectively. By changing the doping concentrations of Er3+, the color of up-conversion luminescence can be tuned from green to red gradually. The luminescence intensity is not reinforce with the increase in the concentration, so the doping concentration of Er3+ should not exceed 2%. If the doping concentration of Er3+ exceeds the range, the concentration has very small effect on the improvement of luminescence intensity.

Structural and optical characterization of Eu3+ doped beta-Ga2O3 nanoparticles using a liquid-phase precursor method.

PubMed

Kim, Moung-O; Kang, Bongkyun; Yoon, Daeho

2013-08-01

Eu3+ doped beta-Ga2O3 and non-doped beta-Ga2O3 nanoparticles were synthesized at 800 degrees C using a liquid-phase precursor (LPP) method, with different annealing times and Eu3+ ion concentrations. Eu3+ doped beta-Ga2O3 nanoparticles showed broad XRD peaks, revealing a second phase compared with the non-doped beta-Ga2O3 nanoparticles. The cathode luminescence (CL) spectra of beta-Ga2O3 and Eu3+ doped beta-Ga2O3 nanoparticles showed a broad band emission (300-500 nm) of imperfection and two component emissions. The luminescence quenching properties of Eu3+ dopant ion concentration appeared gradually beyond 5 mol% in our investigation.

Luminescent nanocomposites of conducting polymers and in-situ grown CdS quantum dots

NASA Astrophysics Data System (ADS)

Borriello, C.; Masala, S.; Bizzarro, V.; Nenna, G.; Re, M.; Pesce, E.; Minarini, C.; Di Luccio, T.

2010-06-01

Luminescent PVK:CdS and P3HT:CdS nanocomposites with enhanced electrooptical properties have been synthesized. The nucleation and growth of CdS nanoparticles have been obtained by the thermolysis of a single Cd and S precursor dispersed in the polymers. The size distribution and morphology of the nanoparticles have been studied by TEM analyses. Monodispersive and very small nanoparticles of diameter below 3 nm in PVK and 2 nm in P3HT, have been obtained. The application of such nanocomposites as emitting layers in OLED devices is discussed.

Luminescent nanocomposites of conducting polymers and in-situ grown CdS quantum dots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borriello, C.; Masala, S.; Nenna, G.

2010-06-02

Luminescent PVK:CdS and P3HT:CdS nanocomposites with enhanced electrooptical properties have been synthesized. The nucleation and growth of CdS nanoparticles have been obtained by the thermolysis of a single Cd and S precursor dispersed in the polymers. The size distribution and morphology of the nanoparticles have been studied by TEM analyses. Monodispersive and very small nanoparticles of diameter below 3 nm in PVK and 2 nm in P3HT, have been obtained. The application of such nanocomposites as emitting layers in OLED devices is discussed.

Aptamer-based multifunctional ligand-modified UCNPs for targeted PDT and bioimaging.

PubMed

Hou, Weijia; Liu, Yuan; Jiang, Ying; Wu, Yuan; Cui, Cheng; Wang, Yanyue; Zhang, Liqin; Teng, I-Ting; Tan, Weihong

2018-06-14

We designed an aptamer-based multifunctional ligand which, upon conjugation to the surface of upconversion nanoparticles (UCNPs), could realize phase transfer, covalent photosensitizer (PS) loading, and cancer cell targeting in one simple step. The as-built PDT nanodrug is selectively internalized into cancer cells and it exhibits highly efficient and selective cytotoxicity.

Upconversion Nanoparticles for Photodynamic Therapy and Other Cancer Therapeutics

PubMed Central

Wang, Chao; Cheng, Liang; Liu, Zhuang

2013-01-01

Photodynamic therapy (PDT) is a non-invasive treatment modality for a variety of diseases including cancer. PDT based on upconversion nanoparticles (UCNPs) has received much attention in recent years. Under near-infrared (NIR) light excitation, UCNPs are able to emit high-energy visible light, which can activate surrounding photosensitizer (PS) molecules to produce singlet oxygen and kill cancer cells. Owing to the high tissue penetration ability of NIR light, NIR-excited UCNPs can be used to activate PS molecules in much deeper tissues compared to traditional PDT induced by visible or ultraviolet (UV) light. In addition to the application of UCNPs as an energy donor in PDT, via similar mechanisms, they could also be used for the NIR light-triggered drug release or activation of 'caged' imaging or therapeutic molecules. In this review, we will summarize the latest progresses regarding the applications of UCNPs for photodynamic therapy, NIR triggered drug and gene delivery, as well as several other UCNP-based cancer therapeutic approaches. The future prospects and challenges in this emerging field will be also discussed. PMID:23650479

Single Upconversion Nanoparticle-Bacterium Cotrapping for Single-Bacterium Labeling and Analysis.

PubMed

Xin, Hongbao; Li, Yuchao; Xu, Dekang; Zhang, Yueli; Chen, Chia-Hung; Li, Baojun

2017-04-01

Detecting and analyzing pathogenic bacteria in an effective and reliable manner is crucial for the diagnosis of acute bacterial infection and initial antibiotic therapy. However, the precise labeling and analysis of bacteria at the single-bacterium level are a technical challenge but very important to reveal important details about the heterogeneity of cells and responds to environment. This study demonstrates an optical strategy for single-bacterium labeling and analysis by the cotrapping of single upconversion nanoparticles (UCNPs) and bacteria together. A single UCNP with an average size of ≈120 nm is first optically trapped. Both ends of a single bacterium are then trapped and labeled with single UCNPs emitting green light. The labeled bacterium can be flexibly moved to designated locations for further analysis. Signals from bacteria of different sizes are detected in real time for single-bacterium analysis. This cotrapping method provides a new approach for single-pathogenic-bacterium labeling, detection, and real-time analysis at the single-particle and single-bacterium level. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

NIR-induced highly sensitive detection of latent finger-marks by NaYF4:Yb,Er upconversion nanoparticles in a dry powder state

PubMed Central

Wang, Meng; Li, Ming; Yang, Mingying; Zhang, Xiaomei; Yu, Aoyang; Zhu, Ye; Qiu, Penghe; Mao, Chuanbin

2016-01-01

The most commonly found fingermarks at crime scenes are latent and, thus, an efficient method for detecting latent fingermarks is very important. However, traditional developing techniques have drawbacks such as low detection sensitivity, high background interference, complicated operation, and high toxicity. To tackle this challenge, we employed fluorescent NaYF4:Yb,Er upconversion nanoparticles (UCNPs), which can fluoresce visible light when excited by 980 nm human-safe near-infrared light, to stain the latent fingermarks on various substrate surfaces. The UCNPs were successfully used as a novel fluorescent label for the detection of latent fingermarks with high sensitivity, low background, high efficiency, and low toxicity on various substrates including non-infiltrating materials (glass, marble, aluminum alloy sheets, stainless steel sheets, aluminum foils, and plastic cards), semi-infiltrating materials (floor leathers, ceramic tiles, wood floor, and painted wood), and infiltrating materials such as various types of papers. This work shows that UCNPs are a versatile fluorescent label for the facile detection of fingermarks on virtually any material, enabling their practical applications in forensic sciences. PMID:27818741

Spectral Selectivity of Plasmonic Interactions between Individual Up-Converting Nanocrystals and Spherical Gold Nanoparticles.

PubMed

Piątkowski, Dawid; Schmidt, Mikołaj K; Twardowska, Magdalena; Nyk, Marcin; Aizpurua, Javier; Maćkowski, Sebastian

2017-08-04

We experimentally demonstrate strong spectral selectivity of plasmonic interaction that occurs between α-NaYF₄:Er 3+ /Yb 3+ nanocrystals, which feature two emission bands, and spherical gold nanoparticles, with plasmon frequency resonant with one of the emission bands. Spatially-resolved luminescence intensity maps acquired for individual nanocrystals, together with microsecond luminescence lifetime images, show two qualitatively different effects that result from the coupling between plasmon excitations in metallic nanoparticles and emitting states of the nanocrystals. On the one hand, we observe nanocrystals, whose emission intensity is strongly enhanced for both resonant and non-resonant bands with respect to the plasmon resonance. Importantly, this increase is accompanied with shortening of luminescence decays times. In contrast, a significant number of nanocrystals exhibits almost complete quenching of the emission resonant with the plasmon resonance of gold nanoparticles. Theoretical analysis indicates that such an effect can occur for emitters placed at distances of about 5 nm from gold nanoparticles. While under these conditions, both transitions experience significant increases of the radiative emission rates due to the Purcell effect, the non-radiative energy transfer between resonant bands results in strong quenching, which in that situation nullifies the enhancement.

The in vivo activation of persistent nanophosphors for optical imaging of vascularization, tumours and grafted cells

NASA Astrophysics Data System (ADS)

Maldiney, Thomas; Bessière, Aurélie; Seguin, Johanne; Teston, Eliott; Sharma, Suchinder K.; Viana, Bruno; Bos, Adrie J. J.; Dorenbos, Pieter; Bessodes, Michel; Gourier, Didier; Scherman, Daniel; Richard, Cyrille

2014-04-01

Optical imaging for biological applications requires more sensitive tools. Near-infrared persistent luminescence nanoparticles enable highly sensitive in vivo optical detection and complete avoidance of tissue autofluorescence. However, the actual generation of persistent luminescence nanoparticles necessitates ex vivo activation before systemic administration, which prevents long-term imaging in living animals. Here, we introduce a new generation of optical nanoprobes, based on chromium-doped zinc gallate, whose persistent luminescence can be activated in vivo through living tissues using highly penetrating low-energy red photons. Surface functionalization of this photonic probe can be adjusted to favour multiple biomedical applications such as tumour targeting. Notably, we show that cells can endocytose these nanoparticles in vitro and that, after intravenous injection, we can track labelled cells in vivo and follow their biodistribution by a simple whole animal optical detection, opening new perspectives for cell therapy research and for a variety of diagnosis applications.

Investigation of luminescent properties of LaF3:Nd3+ nanoparticles

NASA Astrophysics Data System (ADS)

Wyrwas, Marek; Miluski, Piotr; Zmojda, Jacek; Kochanowicz, Marcin; Jelen, Piotr; Sitarz, Maciej; Dorosz, Dominik

2015-09-01

Lanthanum fluoride nanoparticles doped with Nd3+ ions obtained via solvothermal method have been presented. Doped nanoparticles were prepared in two-step method. Firstly rare-earth chlorides were synthesized from oxides and then they were used to prepare LaF3 particles. The luminescence spectra shows typical for crystalline materials Stark splitting at 880 nm corresponding 4F3/2 to 4I9/2 level transition and 1060 nm matching 4F3/2 to 4I11/2 level transition. The highest luminescence intensity was achieved for sample doped with 0.75% wt. of Nd3+, and the longest decay time for sample doped with 0.5% wt. which reached 328 μs. The XRD pattern analysis confirmed that obtained material consists of crystalline LaF3, the grain size was estimated from Sherrer's formula and equaled about 25nm.

Tetherless near-infrared control of brain activity in behaving animals using fully implantable upconversion microdevices.

PubMed

Wang, Ying; Lin, Xudong; Chen, Xi; Chen, Xian; Xu, Zhen; Zhang, Wenchong; Liao, Qinghai; Duan, Xin; Wang, Xin; Liu, Ming; Wang, Feng; He, Jufang; Shi, Peng

2017-10-01

Many nanomaterials can be used as sensors or transducers in biomedical research and they form the essential components of transformative novel biotechnologies. In this study, we present an all-optical method for tetherless remote control of neural activity using fully implantable micro-devices based on upconversion technology. Upconversion nanoparticles (UCNPs) were used as transducers to convert near-infrared (NIR) energy to visible light in order to stimulate neurons expressing different opsin proteins. In our setup, UCNPs were packaged in a glass micro-optrode to form an implantable device with superb long-term biocompatibility. We showed that remotely applied NIR illumination is able to reliably trigger spiking activity in rat brains. In combination with a robotic laser projection system, the upconversion-based tetherless neural stimulation technique was implemented to modulate brain activity in various regions, including the striatum, ventral tegmental area, and visual cortex. Using this system, we were able to achieve behavioral conditioning in freely moving animals. Notably, our microscale device was at least one order of magnitude smaller in size (∼100 μm in diameter) and two orders of magnitude lighter in weight (less than 1 mg) than existing wireless optogenetic devices based on light-emitting diodes. This feature allows simultaneous implantation of multiple UCNP-optrodes to achieve modulation of brain function to control complex animal behavior. We believe that this technology not only represents a novel practical application of upconversion nanomaterials, but also opens up new possibilities for remote control of neural activity in the brains of behaving animals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Self-reporting and refoldable profluorescent single-chain nanoparticles.

PubMed

Fischer, Tobias S; Spann, Sebastian; An, Qi; Luy, Burkhard; Tsotsalas, Manuel; Blinco, James P; Mutlu, Hatice; Barner-Kowollik, Christopher

2018-05-28

We pioneer the formation of self-reporting and refoldable profluorescent single-chain nanoparticles (SCNPs) via the light-induced reaction ( λ max = 320 nm) of nitroxide radicals with a photo-active crosslinker. Whereas the tethered nitroxide moiety in these polymers fully quenches the luminescence ( i.e. fluorescence) of the aromatic backbone, nitroxide trapping of a transient C-radical leads to the corresponding closed shell alkoxyamine thereby restoring luminescence of the folded SCNP. Hence, the polymer in the folded state is capable of emitting light, while in the non-folded state the luminescence is silenced. Under oxidative conditions the initially folded SCNPs unfold, resulting in luminescence switch-off and the reestablishment of the initial precursor polymer. Critically, we show that the luminescence can be repeatedly silenced and reactivated. Importantly, the self-reporting character of the SCNPs was followed by size-exclusion chromatography (SEC), dynamic light scattering (DLS), fluorescence, electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and diffusion ordered NMR spectroscopy (DOSY).

Enzymatic-induced upconversion photoinduced electron transfer for sensing tyrosine in human serum.

PubMed

Wu, Qiongqiong; Fang, Aijin; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

2016-03-15

This paper reports a novel nanosensor for tyrosine based on photoinduced electron-transfer (PET) between NaYF4:Yb, Tm upconversion nanoparticles (UCNPs) and melanin-like polymers. Melanin-like films were obtained from catalytic oxidation of tyrosine by tyrosinase, and deposited on the surface of UCNPs, and then quenched the fluorescence of UCNPs. Under the optimized conditions, the fluorescence quenching of UCNPs showed a good linear response to tyrosine concentration in the range of 0.8-100 μΜ with a detection limit of 1.1 μΜ. Meanwhile, it showed good sensitivity, stability and has been successfully applied to the detection of tyrosine in human serum. Copyright © 2015 Elsevier B.V. All rights reserved.

Near-infrared deep brain stimulation via upconversion nanoparticle–mediated optogenetics

NASA Astrophysics Data System (ADS)

Chen, Shuo; Weitemier, Adam Z.; Zeng, Xiao; He, Linmeng; Wang, Xiyu; Tao, Yanqiu; Huang, Arthur J. Y.; Hashimotodani, Yuki; Kano, Masanobu; Iwasaki, Hirohide; Parajuli, Laxmi Kumar; Okabe, Shigeo; Teh, Daniel B. Loong; All, Angelo H.; Tsutsui-Kimura, Iku; Tanaka, Kenji F.; Liu, Xiaogang; McHugh, Thomas J.

2018-02-01

Optogenetics has revolutionized the experimental interrogation of neural circuits and holds promise for the treatment of neurological disorders. It is limited, however, because visible light cannot penetrate deep inside brain tissue. Upconversion nanoparticles (UCNPs) absorb tissue-penetrating near-infrared (NIR) light and emit wavelength-specific visible light. Here, we demonstrate that molecularly tailored UCNPs can serve as optogenetic actuators of transcranial NIR light to stimulate deep brain neurons. Transcranial NIR UCNP-mediated optogenetics evoked dopamine release from genetically tagged neurons in the ventral tegmental area, induced brain oscillations through activation of inhibitory neurons in the medial septum, silenced seizure by inhibition of hippocampal excitatory cells, and triggered memory recall. UCNP technology will enable less-invasive optical neuronal activity manipulation with the potential for remote therapy.

Synthesis of Mg{sub 2}SiO{sub 4}:Dy{sup 3+} nanoparticles by hydrothermal method and investigation of their thermo and photo luminescence properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghahari, M., E-mail: maghahari@icrc.ac.ir; Mostafavi, K.

2016-05-15

Highlights: • Mg{sub 2}SiO{sub 4}:Dy{sup 3+} nanoparticles have been prepared by hydrothermal and combustion methods. • Thermo and photo luminescent behavior of Mg{sub 2}SiO{sub 4}:Dy{sup 3+} was studied. • The effect of synthesis method on TL properties of Mg{sub 2}SiO{sub 4}:Dy{sup 3+} was investigated. • The optimal dopant concentration for thermo-luminescent property was obtained. - Abstract: In this study, photo and thermo-luminescent properties of Nano crystalline Mg{sub 2}SiO{sub 4}:Dy{sup 3+} prepared by a hydrothermal method were studied and compared to those of nanoparticles prepared by combustion method. The synthesized sample was characterized by X-ray diffraction, transmission electron microscopy, scanning electronmore » microscopy and photoluminescence spectroscopy. The effect of Dy concentration on photo and thermoluminescent intensities was studied. The X-ray diffraction (XRD) patterns of the samples revealed that forsterite was formed as a major phase for all the samples. The crystallite size was found to be in the range of 20–50 nm. The thermo luminescent glow curve indicated that the hydrothermal sample was more efficient than the combustion sample. Two prominent TL bands located at 200 nm and 320 nm were recorded. The prepared nanoparticles exhibited a roughly linear dose response to absorbed dose of 1000 Gy received from 60Co gamma source, suggesting that nanomaterial could be a good candidate for high dose dosimetry.« less

Core–shell Ag@SiO{sub 2} nanoparticles of different silica shell thicknesses: Preparation and their effects on photoluminescence of lanthanide complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Jie; Li, Yuan; Chen, Yingnan

Highlights: • Ag@SiO{sub 2} nanoparticles of different silica shell thicknesses were prepared via the Stöber process. • Sm and Dy complexes with benzoate, 1,10-phenanthroline and 2,2′-bipyridine were synthesized. • The complex-doped Ag@SiO{sub 2} composites show stronger luminescent intensities than pure complexes. • The luminescent intensities of the composites strongly depend on the SiO{sub 2} shell thickness. - Abstract: Three kinds of almost spherical core–shell Ag@SiO{sub 2} nanoparticles of different silica shell thicknesses (10, 25 and 80 nm) were prepared via the Stöber process. The Ag core nanoparticles were prepared by reducing silver nitrate with sodium citrate. The size, morphology andmore » structure of core–shell Ag@SiO{sub 2} nanoparticles were characterized by transmission electron microscopy. Subsequently, eight kinds of lanthanide complexes with benzoate, 1,10-phenanthroline and 2,2′-bipyridine were synthesized. The composition of the lanthanide complexes was characterized by elemental analysis, IR and UV spectra. Finally, lanthanide complexes were attached to the surface of Ag@SiO{sub 2} nanoparticles to form lanthanide-complex-doped Ag@SiO{sub 2} nanocomposites. The results show that the complex-doped Ag@SiO{sub 2} nanocomposites display much stronger luminescence intensities than the lanthanide complexes. Furthermore, the luminescence intensities of the lanthanide-complex-doped Ag@SiO{sub 2} nanocomposites with SiO{sub 2} shell thickness of 25 nm are stronger than those of the nanocomposites with SiO{sub 2} shell thickness of 10 and 80 nm.« less

Self-assemble nanoparticles based on polypeptides containing C-terminal luminescent Pt-cysteine complex

NASA Astrophysics Data System (ADS)

Vlakh, E. G.; Grachova, E. V.; Zhukovsky, D. D.; Hubina, A. V.; Mikhailova, A. S.; Shakirova, J. R.; Sharoyko, V. V.; Tunik, S. P.; Tennikova, T. B.

2017-02-01

The growing attention to the luminescent nanocarriers is strongly stimulated by their potential application as drug delivery systems and by the necessity to monitor their distribution in cells and tissues. In this communication we report on the synthesis of amphiphilic polypeptides bearing C-terminal phosphorescent label together with preparation of nanoparticles using the polypeptides obtained. The approach suggested is based on a unique and highly technological process where the new phosphorescent Pt-cysteine complex serves as initiator of the ring-opening polymerization of α-amino acid N-carboxyanhydrides to obtain the polypeptides bearing intact the platinum chromophore covalently bound to the polymer chain. It was established that the luminescent label retains unchanged its emission characteristics not only in the polypeptides but also in more complicated nanoaggregates such as the polymer derived amphiphilic block-copolymers and self-assembled nanoparticles. The phosphorescent nanoparticles display no cytotoxicity and hemolytic activity in the tested range of concentrations and easily internalize into living cells that makes possible in vivo cell visualization, including prospective application in time resolved imaging and drug delivery monitoring.

Luminescent properties of ZrO2:Tb nanoparticles for applications in neuroscience

NASA Astrophysics Data System (ADS)

Słońska, A.; Kaszewski, J.; Wolska-Kornio, E.; Witkowski, B.; Wachnicki, Ł.; Mijowska, E.; Karakitsou, V.; Gajewski, Z.; Godlewski, M.; Godlewski, M. M.

2016-09-01

In this paper a new generation of non-toxic nanoparticles based on the zirconium oxide doped with 0.5%Tb and co-doped by the range of 0-70% with Y was evaluated for the use as a fluorescent biomarker of neuronal trafficking. The ZrO2:Tb nanoparticles were created by microwave driven hydrothermal method. Influence of the yttrium content and thermal processing on the Tb3+ related luminescence emission was discussed. The higher intensities were achieved, when host was cubic and for the nanoparticles with 33 nm. Presence of yttrium was associated with the energy coupling of the host and dopant, wide excitation band is present at 309 and 322 nm before and after calcination respectively.

Interference-enhanced infrared-to-visible upconversion in solid-state thin films sensitized by colloidal nanocrystals

NASA Astrophysics Data System (ADS)

Wu, Mengfei; Jean, Joel; Bulović, Vladimir; Baldo, Marc A.

2017-05-01

Infrared-to-visible photon upconversion has potential applications in photovoltaics, sensing, and bioimaging. We demonstrate a solid-state thin-film device that utilizes sensitized triplet-triplet exciton annihilation, converting infrared photons absorbed by colloidal lead sulfide nanocrystals (NCs) into visible photons emitted from a luminescent dopant in rubrene at low incident light intensities. A typical bilayer device consisting of a monolayer of NCs and a doped film of rubrene is limited by low infrared absorption in the thin NC film. Here, we augment the bilayer with an optical spacer layer and a silver-film back reflector, resulting in interference effects that enhance the optical field and thus the absorption in the NC film. The interference-enhanced device shows an order-of-magnitude increase in the upconverted emission at the wavelength of λ = 610 nm when excited at λ = 980 nm. At incident light intensities above 1.1 W/cm2, the device attains maximum efficiency, converting (1.6 ± 0.2)% of absorbed infrared photons into higher-energy singlet excitons in rubrene.

A fruitful demonstration in sensors based on upconversion luminescence of Yb3+/Er3+codoped Sb2O3-WO3-Li2O (SWL) glass-ceramic

NASA Astrophysics Data System (ADS)

Prasad Sukul, Prasenjit; Kumar, Kaushal

2016-07-01

In this article, erbium and ytterbium doped lithium tungsten antimonate (Yb3+/Er3+:Sb2O3-WO3-Li2O) glass-ceramics (GC) is synthesized and its novel applications in temperature sensing and detection of latent fingerprints is studied. It is also estimated that this material could be useful as a solar cell concentrator. The upconversion emission studies on Yb3+/Er3+:SWL glass-ceramics have shown intense green emission at 525 nm (2H11/2 → 4I15/2) & 545 nm (4s3/2 → 4I15/2). The variation of UC intensities with external temperature have shown a well-fashioned pattern, which suggests that the 2H11/2 and 4S3/2 levels of Er3+ ion are thermally coupled and can act as a temperature sensor in the 300-500 K temperature range. Dry powder of Yb3+/Er3+:SWL glass-ceramic is used to develop latent fingerprint with high contrast in green color on glass slide.

A smart upconversion-based light-triggered polymer for synergetic chemo-photodynamic therapy and dual-modal MR/UCL imaging.

PubMed

Du, Bin; Han, Shuping; Zhao, Feifei; Lim, Kok Hwa; Xi, Hongwei; Su, Xiangjie; Yao, Hanchun; Zhou, Jie

2016-10-01

We have developed a novel nanocomposite to achieve effective therapy and live surveillance of tumor tissue. In this study, fullerene (C 60 ) with iron oxide (Fe 3 O 4 ) nanoparticles and upconversion nanophosphors (UCNPs) was loaded into N-succinyl-N'-4-(2-nitrobenzyloxy)-succinyl-chitosan micelles (SNSC) with good biocompatibility. In addition, hydrophobic anticancer drug docetaxel (DTX) was also loaded into the nanocomposites. The experiments conducted in vitro and in vivo demonstrated that C 60 /Fe 3 O 4 -UCNPs@DTX@SNSC can act synergistically to kill tumor cells by releasing chemotherapy drugs at specific target site as well as generating reactive oxygen using 980nm. In addition, it can also be used for non-invasive deep magnetic resonance and upconversion fluorescence dual-mode imaging. The results indicated that this system provided an efficient method to surmount the drawback of UV or visible light-responsive polymeric systems for controlled drug release and generated reactive oxygen in deep tissues and ultimately realized the integration of dual-modal imaging and treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

Origin of near to middle infrared luminescence and energy transfer process of Er(3+)/Yb(3+)co-doped fluorotellurite glasses under different excitations.

PubMed

Huang, Feifei; Liu, Xueqiang; Ma, Yaoyao; Kang, Shuai; Hu, Lili; Chen, Danping

2015-02-04

We report the near to middle infrared luminescence and energy transfer process of Er(3+)/Yb(3+) co-doped fluorotellurite glasses under 980, 1550 and 800 nm excitations, respectively. Using a 980 nm laser diode pump, enhanced 1.5 and 2.7 μm emissions from Er(3+):I13/2→(4)I15/2 and I11/2→(4)I13/2 transitions are observed, in which Yb(3+) ions can increase pumping efficiency and be used as energy transfer donors. Meanwhile, Yb(3+) can also be used as an acceptor and intensive upconversion luminescence of around 1000 nm is achieved from Er(3+):I11/2→(4)I15/2 and Yb(3+): F5/2→(4)F7/2 transitions using 1550 nm excitation. In addition, the luminescence properties and variation trendency by 800 nm excitation is similar to that using 1550 nm excitation. The optimum Er(3+) and Yb(3+) ion ratio is 1:1.5 and excess Yb(3+) ions decrease energy transfer efficiency under the two pumpings. These results indicate that Er(3+)/Yb(3+) co-doped fluorotellurite glasses are potential middle- infrared laser materials and may be used to increase the efficiency of the silicon solar cells.

Origin of near to middle infrared luminescence and energy transfer process of Er3+/Yb3+co-doped fluorotellurite glasses under different excitations

PubMed Central

Huang, Feifei; Liu, Xueqiang; Ma, Yaoyao; Kang, Shuai; Hu, Lili; Chen, Danping

2015-01-01

We report the near to middle infrared luminescence and energy transfer process of Er3+/Yb3+ co-doped fluorotellurite glasses under 980, 1550 and 800 nm excitations, respectively. Using a 980 nm laser diode pump, enhanced 1.5 and 2.7 μm emissions from Er3+:I13/2→4I15/2 and I11/2→4I13/2 transitions are observed, in which Yb3+ ions can increase pumping efficiency and be used as energy transfer donors. Meanwhile, Yb3+ can also be used as an acceptor and intensive upconversion luminescence of around 1000 nm is achieved from Er3+:I11/2→4I15/2 and Yb3+: F5/2→4F7/2 transitions using 1550 nm excitation. In addition, the luminescence properties and variation trendency by 800 nm excitation is similar to that using 1550 nm excitation. The optimum Er3+ and Yb3+ ion ratio is 1:1.5 and excess Yb3+ ions decrease energy transfer efficiency under the two pumpings. These results indicate that Er3+/Yb3+ co-doped fluorotellurite glasses are potential middle- infrared laser materials and may be used to increase the efficiency of the silicon solar cells. PMID:25648651

A pre-protective strategy for precise tumor targeting and efficient photodynamic therapy with a switchable DNA/upconversion nanocomposite.

PubMed

Yu, Zhengze; Ge, Yegang; Sun, Qiaoqiao; Pan, Wei; Wan, Xiuyan; Li, Na; Tang, Bo

2018-04-14

Tumor-specific targeting based on folic acid (FA) is one of the most common and significant approaches in cancer therapy. However, the expression of folate receptors (FRs) in normal tissues will lead to unexpected targeting and unsatisfactory therapeutic effect. To address this issue, we develop a pre-protective strategy for precise tumor targeting and efficient photodynamic therapy (PDT) using a switchable DNA/upconversion nanocomposite, which can be triggered in the acidic tumor microenvironment. The DNA/upconversion nanocomposite is composed of polyacrylic acid (PAA) coated upconversion nanoparticles (UCNPs), the surface of which is modified using FA and chlorin e6 (Ce6) functionalized DNA sequences with different lengths. Initially, FA on the shorter DNA was protected by a longer DNA to prevent the bonding to FRs on normal cells. Once reaching the acidic tumor microenvironment, C base-rich longer DNA forms a C-quadruplex, resulting in the exposure of the FA groups and the bonding of FA and FRs on cancer cell membranes to achieve precise targeting. Simultaneously, the photosensitizer chlorin e6 (Ce6) gets close to the surface of UCNPs, enabling the excitation of Ce6 to generate singlet oxygen ( 1 O 2 ) under near infrared light via Förster resonance energy transfer (FRET). In vivo experiments indicated that higher tumor targeting efficiency was achieved and the tumor growth was greatly inhibited through the pre-protective strategy.

Paramagnetic Nanocrystals: Remarkable Lanthanide-Doped Nanoparticles with Varied Shape, Size, and Composition.

PubMed

Holmberg, Rebecca J; Aharen, Tomoko; Murugesu, Muralee

2012-12-20

Magnetic nanoparticles have been developed in recent years with applications in unique and crucial areas such as biomedicine, data storage, environmental remediation, catalysis, and so forth. NaYF4 nanoparticles were synthesized and isolated with lanthanide dopant percentages, confirmed by ICP-OES measurements, of Er, Yb, Tb, Gd, and Dy that were in agreement with the targeted ratios. SEM images showed a distinct variation in particle size and shape with dopant type and percentage. HRTEM and XRD studies confirmed the particles to be crystalline, possessing both α and β phases. Magnetic measurements determined that all of the nanoparticles were paramagnetic and did not exhibit a blocking temperature from 2 to 300 K. The multifunctional properties of these nanoparticles make them suitable for many applications, such as multimodal imaging probes, up-conversion fluorescent markers, as well as MRI contrast agents.

Species Specific Bacterial Spore Detection Using Lateral-Flow Immunoassay with DPA-Triggered Tb Luminescence

NASA Technical Reports Server (NTRS)

Ponce, Adrian

2003-01-01

A method of detecting bacterial spores incorporates (1) A method of lateral-flow immunoassay in combination with (2) A method based on the luminescence of Tb3+ ions to which molecules of dipicolinic acid (DPA) released from the spores have become bound. The present combination of lateral-flow immunoassay and DPA-triggered Tb luminescence was developed as a superior alternative to a prior lateral-flow immunoassay method in which detection involves the visual observation and/or measurement of red light scattered from colloidal gold nanoparticles. The advantage of the present combination method is that it affords both (1) High selectivity for spores of the species of bacteria that one seeks to detect (a characteristic of lateral-flow immunoassay in general) and (2) Detection sensitivity much greater (by virtue of the use of DPA-triggered Tb luminescence instead of gold nanoparticles) than that of the prior lateral-flow immunoassay method

Molecularly Targeted Dose-Enhancement Radiotherapy Using Gold and Luminescent Nanoparticles in an Orthotopic Human Prostate Cancer Rat Model

DTIC Science & Technology

2013-10-01

cell lines, such as cervix cancer cell line (HeLa) and breast cancer cell line (MDA-MB-231), were also employed. The experiments with other cell lines...breast cancer cell line (MDA-MB- 231), and cervix cancer cell line (HeLa). Different from our hypothesis, prostate cancer cell lines did not present...Radiotherapy Using Gold and Luminescent Nanoparticles in an Orthotopic Human Prostate Cancer Rat Model PRINCIPAL INVESTIGATOR: Kwang Song

Rare-earth Nanoparticle-induced Cytotoxicity on Spatial Cognition Memory of Mouse Brain.

PubMed

Lin, Cai-Hou; Liu, Gui-Fen; Chen, Jing; Chen, Yan; Lin, Ru-Hui; He, Hong-Xing; Chen, Jian-Ping

2017-11-20

Luminescent rare-earth-based nanoparticles have been increasingly used in nanomedicine due to their excellent physicochemical properties, such as biomedical imaging agents, drug carriers, and biomarkers. However, biological safety of the rare-earth-based nanomedicine is of great significance for future development in practical applications. In particular, biological effects of rare-earth nanoparticles on human's central nervous system are still unclear. This study aimed to investigate the potential toxicity of rare-earth nanoparticles in nervous system function in the case of continuous exposure. Adult ICR mice were randomly divided into seven groups, including control group (receiving 0.9% normal saline) and six experimental groups (10 mice in each group). Luminescent rare-earth-based nanoparticles were synthesized by a reported co-precipitation method. Two different sizes of the nanoparticles were obtained, and then exposed to ICR mice through caudal vein injection at 0.5, 1.0, and 1.5 mg/kg body weight in each day for 7 days. Next, a Morris water maze test was employed to evaluate impaired behaviors of their spatial recognition memory. Finally, histopathological examination was implemented to study how the nanoparticles can affect the brain tissue of the ICR mice. Two different sizes of rare-earth nanoparticles have been successfully obtained, and their physical properties including luminescence spectra and nanoparticle sizes have been characterized. In these experiments, the rare-earth nanoparticles were taken up in the mouse liver using the magnetic resonance imaging characterization. Most importantly, the experimental results of the Morris water maze tests and histopathological analysis clearly showed that rare-earth nanoparticles could induce toxicity on mouse brain and impair the behaviors of spatial recognition memory. Finally, the mechanism of adenosine triphosphate quenching by the rare-earth nanoparticles was provided to illustrate the toxicity on the mouse brain. This study suggested that long-term exposure of high-dose bare rare-earth nanoparticles caused an obvious damage on the spatial recognition memory in the mice.

Dual-excitation upconverting nanoparticle and quantum dot aptasensor for multiplexed food pathogen detection.

PubMed

Kurt, Hasan; Yüce, Meral; Hussain, Babar; Budak, Hikmet

2016-07-15

In this report, a dual-excitation sensing method was developed using aptamer-functionalized quantum dots and upconverting nanoparticles, exhibiting Stokes and anti-Stokes type excitation profiles, respectively. Conjugation of the aptamer-functionalized luminescent nanoparticles with the magnetic beads, comprising short DNA sequences that were partially complementary to the aptamer sequences, enabled facile separation of the analyte-free conjugates for fluorescent measurement. UV-Visible spectroscopy, Circular Dichroism spectroscopy, Dynamic Light Scattering and Polyacrylamide Gel Electrophoresis techniques were used to characterize the aptamer probes developed. The target-specific luminescent conjugates were applied for multiplex detection of model food pathogens, Salmonella typhimurium, and Staphylococcus aureus, in which the fluorescent emission spectra were obtained under UV excitation at 325nm for quantum dots and NIR excitation at 980nm for upconverting nanoparticles, respectively. The dual-excitation strategy was aimed to minimize cross-talk between the luminescent signals for multiplexed detection, and yielded limit of detection values of 16 and 28cfumL(-1) for Staphylococcus aureus, and Salmonella typhimurium, respectively. By employing a greater number of quantum dots and upconverting nanoparticles with non-overlapping fluorescent emissions, the proposed methodology might be exploited further to detect several analytes, simultaneously. Copyright © 2016 Elsevier B.V. All rights reserved.

NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}, Er{sup 3+}/Yb{sup 3+}) microspheres: the synthesis and optical properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Zhiyi; Wang, Zhiying; Fu, Linlin

The strong green upconversion (UC) emission were observed in various Er{sup 3+}, Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} samples synthesized via a hydrothermal route. The UC intensity depends on the dopant concentration, and the optimal UC emission was obtained in NaLa(MoO{sub 4}){sub 2}: 0.02Er{sup 3+}/0.10 Yb{sup 3+}. - Highlights: • The NaLa(MoO{sub 4}){sub 2} microspheres doped with Eu{sup 3+}, Sm{sup 3+} and Er{sup 3+}/Yb{sup 3+} were synthesized by a hydrothermal method. • The effects of the EDTA in the initial solution crystal phase and morphology were studied. • The down-conversion luminescence properties of NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+}more » = Eu{sup 3+}, Sm{sup 3+}) were investigated. • The UC luminescence properties and mechanism of Er{sup 3+}/Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} was discussed. - Abstract: NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}) microspheres have been synthesized at 180 °C via a facile EDTA-mediated hydrothermal route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), photoluminescence (PL) spectra were employed to characterize the samples. It was found that the amount of EDTA in the initial solution was responsible for crystal phase and shape determination. The effect of Eu{sup 3+} and Sm{sup 3+} doping concentrations on the luminescent intensity was also investigated in details. Furthermore, the up-conversion (UC) emissions have been observed in a series of Er{sup 3+}/Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} samples. Concentration dependent studies revealed that the optimal composition was realized for a 2% Er{sup 3+} and 10% Yb{sup 3+}-doping concentration.« less

High quantum-yield phosphors via quantum splitting and upconversion

NASA Astrophysics Data System (ADS)

Jeong, Joayoung

The Gd3+ ion has been used to induce quantum splitting in luminescent materials by using cross-relaxation energy transfer (CRET). In Nd:LiGdF4, quantum splitting results from a two-step CRET between Gd3+ and Nd3+, first involving a transition 6G→6I on Gd3+ and an excitation within the 4f3 configuration of Nd3+ followed by a second CRET that brings Gd3+ to 6P7/2. The excited Nd3+ ion rapidly relaxes nonradiatively to the emitting 4F3/2. The excited Gd3+ ion then transfers its energy back to Nd3+, which gives rise to the second photon. The result is a quantum yield of 1.05 +/- 0.35 with emission in the NIR following excitation at 175 nm. GdF3:Pr3+, Eu 3+ also exhibits quantum splitting, but only at very low concentration of Pr3+ (0.3%) and Eu3+ (0.2%), resulting in a quantum yield of approximately 20% under 160-nm excitation. Host intrinsic emission via a self-trapped exciton (STE) was also examined as a means to sensitize Gd3+ emission. The material ScPO4:Gd 3+ exhibits a high absolute quantum yield of 0.9 +/- 0.2 under 170-nm excitation, demonstrating a potentially new and efficient pathway for exciting quantum splitting phosphors. Single crystals of the material GdZrF7 were grown, and its structure was established via single-crystal X-ray diffraction methods. Doped samples of GdZrF7:Yb3+, Er3+ exhibit bright up-conversion luminescence with light output that is up to twice that of a commercial material based on the host Gd2O2S. When doped with Eu3+, the fluoride also emits a nearly white color under vacuum ultraviolet excitation with an absolute quantum yield near 0.9. The new compound Gd4.67(SiO4)3S was synthesized and studied. The structure was established via single-crystal X-ray methods, and the luminescence of Tb3+ samples was investigated.

Synthesis of magnetic and upconversion nanocapsules as multifunctional drug delivery system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Shanshan; Chen, Yinyin; Liu, Bei

Multifunctional hollow nanocapsules with magnetic and upconversion luminescence properties were synthesized. Hollow Fe{sub 3}O{sub 4}@SiO{sub 2} was firstly prepared by using rodlike β-FeOOH as the template followed by silica coating, calcinations and reduction. Then Fe{sub 3}O{sub 4}@SiO{sub 2}@α-NaYF{sub 4}:Yb{sup 3+},Er{sup 3+} nanocapsules (FeSiUCNP) were synthesized by the hydrothermal transformation of the Y(Yb{sup 3+}, Er{sup 3+})(OH)CO{sub 3} (YOC) deposited onto the surface of nanocapsules through a urea-assisted homogeneous precipitation method. The hollow nanocapsules with porous structure provide space and entrance for the drug molecules. Due to the outside shell of α-NaYF{sub 4}:Yb{sup 3+}, Er{sup 3+}, the nanomaterial shows upconverting red emissionmore » upon 980 nm NIR-light excitation. Moreover, the nanocomposites with hollow magnetite core exhibit a high relaxivity with r{sub 2} value of 183 mM{sup −1} s{sup −1}, which reveal the potential as T{sub 2}-weighted contrast agents for magnetic resonance imaging (MRI). The as-prepared nanocapsules can be performed as anti-cancer drug carriers for investigation of drug loading/release properties, which demonstrated a sustained drug release pattern and a comparable cytotoxicity with free doxorubicin (DOX). The multifunctional nanocapsules incorporated upconverting luminescence, T{sub 2}-weighted MRI imaging and drug targeting delivery modalities have great potential for theranostic applications in cancer treatment. - Graphical abstract: Multifunctional hollow nanocapsules with upconverting luminescence, T{sub 2}-weighted MRI imaging and drug targeting delivery modalities were synthesized for cancer treatment. - Highlights: • Multifunctional porous Fe{sub 3}O{sub 4}@SiO{sub 2}@α-NaYF{sub 4}:Yb{sup 3+},Er{sup 3+} nanocapsules were synthesized. • The nanocapsules show upconverting red emission upon 980 nm NIR-light excitation. • The nanocapsules exihibit potential as T{sub 2}-weighted contrast agents for MRI. • The DOX loaded nanocapsules demonstrated a comparable cytotoxicity with free DOX.« less

Microwave-assisted one-pot synthesis of water-soluble rare-earth doped fluoride luminescent nanoparticles with tunable colors

PubMed Central

Mi, Cong-Cong; Tian, Zhen-huang; Han, Bao-fu; Mao, Chuan-bin; Xu, Shu-kun

2012-01-01

Polyethyleneimine (PEI) functionalized multicolor luminescent LaF3 nanoparticles were synthesized via a novel microwave-assisted method, which can achieve fast and uniform heating under eco-friendly and energy efficient conditions. The as-prepared nanoparticles possess a pure hexagonal structure with an average size of about 12 nm. When doped with different ions (Tb3+ and Eu3+), the morphology and structure of the nanoparticles were not changed, whereas the optical properties varied with doped ions and their molar ratio, and as a result emission of four different colors (green, yellow, orange and red) were achieved by simply switching the types of doping ions (Eu3+ versus Tb3 +) and the molar ratio of the two doping ions. PMID:22879690

Interference Lithography for Optical Devices and Coatings

DTIC Science & Technology

2010-01-01

semiconductor quantum dots. J. Chem. Phys. 2004, 121, 7421. 100. Jeon, S.; Braun, P. V., Hydrothermal Synthesis of Er-Doped Luminescent TiO2 Nanoparticles ...Silica Nanoparticle Synthesis .....................................................................23 2.2.2 Polymer Matrix Formulation...41 CHAPTER 3: NANOPARTICLE SYNTHESIS , FUNCTIONALIZATION, AND INCORPORATION INTO

Nanoparticle-based luminescent probes for intracellular sensing and imaging of pH.

PubMed

Schäferling, Michael

2016-05-01

Fluorescence imaging microscopy is an essential tool in biomedical research. Meanwhile, various fluorescent probes are available for the staining of cells, cell membranes, and organelles. Though, to monitor intracellular processes and dysfunctions, probes that respond to ubiquitous chemical parameters determining the cellular function such as pH, pO2 , and Ca(2+) are required. This review is focused on the progress in the design, fabrication, and application of photoluminescent nanoprobes for sensing and imaging of pH in living cells. The advantages of using nanoprobes carrying fluorescent pH indicators compared to single molecule probes are discussed as well as their limitations due to the mostly lysosomal uptake by cells. Particular attention is paid to ratiometric dual wavelength nanosensors that enable intrinsic referenced measurements. Referencing and proper calibration procedures are basic prerequisites to carry out reliable quantitative pH determinations in complex samples such as living cells. A variety of examples will be presented that highlight the diverseness of nanocarrier materials (polymers, micelles, silica, quantum dots, carbon dots, gold, photon upconversion nanocrystals, or bacteriophages), fluorescent pH indicators for the weak acidic range, and referenced sensing mechanisms, that have been applied intracellularly up to now. WIREs Nanomed Nanobiotechnol 2016, 8:378-413. doi: 10.1002/wnan.1366 For further resources related to this article, please visit the WIREs website. © 2015 Wiley Periodicals, Inc.

Excimers from stable and persistent supramolecular radical-pairs in red/NIR-emitting organic nanoparticles and polymeric films.

PubMed

Blasi, Davide; Nikolaidou, Domna M; Terenziani, Francesca; Ratera, Imma; Veciana, Jaume

2017-03-29

In this work, the luminescence properties of new materials based on open-shell molecular systems are studied. In particular, we prepared polymeric films and organic nanoparticles (ONPs) doped with triphenylmethyl radical molecules. ONPs exhibit a uniform size distribution, spherical morphology and high colloidal stability. The emission spectrum of low-doped ONP suspensions and low-doped films is very similar to the emission spectrum of TTM in solution, while the luminescence lifetime and the luminescence quantum yield (LQY) are highly increased. Increasing the radical doping leads to a progressive decrease of the LQY and the appearance of a new broad excimeric band at longer wavelengths, both for ONPs and films. Thus, not only the luminescence properties were improved, but also the formation of excimers from stable and persistent supramolecular radical-pairs was observed for the first time. The good stability and luminescence properties with emission in the red-NIR region (650-800 nm), together with the open-shell nature of the emitter, make these free-radical excimer-forming materials promising candidates for optoelectronic and bioimaging applications.

Dimerization of Organic Dyes on Luminescent Gold Nanoparticles for Ratiometric pH Sensing.

PubMed

Sun, Shasha; Ning, Xuhui; Zhang, Greg; Wang, Yen-Chung; Peng, Chuanqi; Zheng, Jie

2016-02-12

Synergistic effects arising from the conjugation of organic dyes onto non-luminescent metal nanoparticles (NPs) have greatly broadened their applications in both imaging and sensing. Herein, we report that conjugation of a well-known pH-insensitive dye, tetramethyl-rhodamine (TAMRA), to pH-insensitive luminescent gold nanoparticles (AuNPs) can lead to an ultrasmall nanoindicator that can fluorescently report local pH in a ratiometric way. Such synergy originated from the dimerization of TAMRA on AuNPs, of which geometry was very sensitive to surface charges of the AuNPs and can be reversely modulated through protonation of surrounding glutathione ligands. Not limited to pH-insensitive dyes, this pH-dependent dimerization can also enhance the pH sensitivity of fluorescein, a well-known pH-sensitive dye, within a larger pH range, opening up a new pathway to design ultrasmall fluorescent ratiometric nanoindicators with tunable wavelengths and pH response ranges. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radioluminescence studies of colloidal oleate-capped β-Na(Gd,Lu)F4:Ln3+ nanoparticles (Ln = Ce, Eu, Tb).

PubMed

Cooper, Daniel R; Capobianco, John A; Seuntjens, Jan

2018-04-26

We report on the synthesis, characterization, and radioluminescence quantification of several new varieties of nanoparticles with the general composition β-NaLnF4, incorporating known luminescent activator/sensitizer pairs. Using Monte Carlo modeling to complement luminescence measurements, we have calculated the radioluminescence yields and intrinsic conversion efficiencies of colloidally-dispersed nanoparticles by comparison to an organic liquid scintillator. While five of the compositions had low to modest radioluminescence yields relative to bulk materials, colloidal β-Na(Lu0.65Gd0.2Tb0.15)F4 displayed a strong output of 39 460 photons per MeV absorbed, comparable to some of the best non-hygroscopic bulk crystal scintillators and X-ray phosphors such as Gd2O2S:Tb. Measurements of β-Na(Lu0.65Gd0.2Tb0.15)F4 powder samples revealed persistent luminescence as well as stable charge trapping, warranting further investigation.

Direct observation of the core/double-shell architecture of intense dual-mode luminescent tetragonal bipyramidal nanophosphors

NASA Astrophysics Data System (ADS)

Kim, Su Yeon; Jeong, Jong Seok; Mkhoyan, K. Andre; Jang, Ho Seong

2016-05-01

Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce3+ to Tb3+ under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm-2 and 73.0 +/- 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered.Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce3+ to Tb3+ under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm-2 and 73.0 +/- 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered. Electronic supplementary information (ESI) available: XRD patterns, PL and PLE spectra, SEM and HR-TEM images, PL decay times, photographs showing the transparent nanophosphor solutions and their dual-mode luminescence, and additional EDX data. See DOI: 10.1039/c5nr05722a

Light-Driven Chiral Molecular Motors for Passive Agile Filters

DTIC Science & Technology

2014-05-20

liquid crystal , we fabricated the self-organized, phototubable 3D photonic superstructure, i.e. photoresponsive monodisperse cholesteric liquid...systems for applications. Here the new light-driven chiral molecular switch and upconversion nanoparticles, doped in a liquid crystal media, were...the bottom-up nanofabrication of intelligent molecular devices. Light-driven chiral molecular switches or motors in liquid crystal (LC) media that

Efficient up-conversion in Yb:Er:NaT(XO4)2 thermal nanoprobes. Imaging of their distribution in a perfused mouse

PubMed Central

Serrano, María Dolores; Han, Xiumei; Cascales, Concepción; Cantero, Marta; Montoliu, Lluís; Arza, Elvira; Caiolfa, Valeria R.; Zamai, Moreno

2017-01-01

Yb and Er codoped NaT(XO4)2 (T = Y, La, Gd, Lu and X = Mo, W) disordered oxides show a green (Er3+ related) up-conversion (UC) efficiency comparable to that of Yb:Er:β-NaYF4 compound and unless 3 times larger UC ratiometric thermal sensitivity. The similar UC efficiency of Yb:Er doped NaT(XO4)2 and β-NaYF4 compounds allowed testing equal subcutaneous depths of ex-vivo chicken tissue in both cases. This extraordinary behavior for NaT(XO4)2 oxides with large cutoff phonon energy (ħω≈ 920 cm-1) is ascribed to 4F9/2 electron population recycling to higher energy 4G11/2 level by a phonon assisted transition. Crystalline nanoparticles of Yb:Er:NaLu(MoO4)2 have been synthesized by sol-gel with sizes most commonly in the 50–80 nm range, showing a relatively small reduction of the UC efficiency with regards to bulk materials. Fluorescence lifetime and multiphoton imaging microscopies show that these nanoparticles can be efficiently distributed to all body organs of a perfused mouse. PMID:28542327

Novel and easy access to highly luminescent Eu and Tb doped ultra-small CaF2, SrF2 and BaF2 nanoparticles - structure and luminescence.

PubMed

Ritter, Benjamin; Haida, Philipp; Fink, Friedrich; Krahl, Thoralf; Gawlitza, Kornelia; Rurack, Knut; Scholz, Gudrun; Kemnitz, Erhard

2017-02-28

A universal fast and easy access at room temperature to transparent sols of nanoscopic Eu 3+ and Tb 3+ doped CaF 2 , SrF 2 and BaF 2 particles via the fluorolytic sol-gel synthesis route is presented. Monodisperse quasi-spherical nanoparticles with sizes of 3-20 nm are obtained with up to 40% rare earth doping showing red or green luminescence. In the beginning luminescence quenching effects are only observed for the highest content, which demonstrates the unique and outstanding properties of these materials. From CaF 2 :Eu10 via SrF 2 :Eu10 to BaF 2 :Eu10 a steady increase of the luminescence intensity and lifetime occurs by a factor of ≈2; the photoluminescence quantum yield increases by 29 to 35% due to the lower phonon energy of the matrix. The fast formation process of the particles within fractions of seconds is clearly visualized by exploiting appropriate luminescence processes during the synthesis. Multiply doped particles are also available by this method. Fine tuning of the luminescence properties is achieved by variation of the Ca-to-Sr ratio. Co-doping with Ce 3+ and Tb 3+ results in a huge increase (>50 times) of the green luminescence intensity due to energy transfer Ce 3+ → Tb 3+ . In this case, the luminescence intensity is higher for CaF 2 than for SrF 2 , due to a lower spatial distance of the rare earth ions.

Silica nanoparticles for micro-particle imaging velocimetry: fluorosurfactant improves nanoparticle stability and brightness of immobilized iridium(III) complexes.

PubMed

Lewis, David J; Dore, Valentina; Rogers, Nicola J; Mole, Thomas K; Nash, Gerard B; Angeli, Panagiota; Pikramenou, Zoe

2013-11-26

To establish highly luminescent nanoparticles for monitoring fluid flows, we examined the preparation of silica nanoparticles based on immobilization of a cyclometalated iridium(III) complex and an examination of the photophysical studies provided a good insight into the Ir(III) microenvironment in order to reveal the most suitable silica nanoparticles for micro particle imaging velocimetry (μ-PIV) studies. Iridium complexes covalently incorporated at the surface of preformed silica nanoparticles, [Ir-4]@Si500-Z, using a fluorinated polymer during their preparation, demonstrated better stability than those without the polymer, [Ir-4]@Si500, as well as an increase in steady state photoluminescence intensity (and therefore particle brightness) and lifetimes which are increased by 7-fold compared with nanoparticles with the same metal complex attached covalently throughout their core, [Ir-4]⊂Si500. Screening of the nanoparticles in fluid flows using epi-luminescence microscopy also confirm that the brightest, and therefore most suitable particles for microparticle imaging velocimetry (μ-PIV) measurements are those with the Ir(III) complex immobilized at the surface with fluorosurfactant, that is [Ir-4]@Si500-Z. μ-PIV studies demonstrate the suitability of these nanoparticles as nanotracers in microchannels.

Y1-receptor-ligand-functionalized ultrasmall upconversion nanoparticles for tumor-targeted trimodality imaging and photodynamic therapy with low toxicity.

PubMed

Yu, Zhangsen; Xia, Yuanzhi; Xing, Jie; Li, Zihou; Zhen, Jianjun; Jin, Yinhua; Tian, Yuchen; Liu, Chuang; Jiang, Zhenqi; Li, Juan; Wu, Aiguo

2018-05-31

Achieving efficient photodynamic therapy (PDT) in deeper biological tissue is still the biggest bottleneck that limits its widespread application in clinic. Although deeper biological tissue PDT could be realized through a combination of upconversion nanoparticles with a photosensitizer, issues with particle-size-induced upconversion fluorescence (UF) reduction and the related in vivo toxicity still cannot be solved properly. In this study, we synthesized Y1Rs-ligand [Pro30, Nle31, Bpa32, Leu34]NPY(28-36) (NPY)-modified and photosensitizer MC540-loaded LiLuF4:Yb,Er@nLiGdF4@mSiO2 multifunctional nanocomposites (MNPs) with a core-multishell structure and ultrasmall size. Their in vitro and in vivo breast tumor targeting, trimodality imaging performance, PDT therapeutic efficacy, and acute toxicity were evaluated. Our results demonstrated that the core-multishell MNPs(MC540) could achieve excellent UF imaging, and that doping with Gd3+ and Lu3+ rare earth ions could enhance the MR and CT imaging performance. In addition, the mSiO2 shell provided a higher loading rate for the photosensitizer MC540, and the DSPE-PEG thin layer coating outside the MNPs(MC540) further improved the water solubility and biocompatibility, reducing the acute toxicity of the nanocomposites. Finally, the NPY modification enhanced the targetability of MNPs(MC540)/DSPE-PEG-NPY to breast tumors, improving the trimodality UF, CT, and MR imaging performance and PDT efficacy for Y1-receptor-overexpressed breast cancer. In general, our developed multifunctional nanocomposites can serve as a theranostic agent with low toxicity, providing great potential for their use in clinical breast cancer diagnosis and therapy.

Synthesis, Characterization and Comparative Luminescence Studies of Rare-Earth-Doped Gd2O3 Nanoparticles

NASA Astrophysics Data System (ADS)

Pyngrope, D.; Singh, L. R.; Prasad, A. I.; Bora, A.

2018-04-01

A facile direct precipitation method was used for the synthesis of luminescence nanomaterial. Gd2O3 doped with rare earth element Eu3+ is synthesized by polyol route. The synthesized nanoparticles show their characteristic red emission. The nanoparticles are characterized by x-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence (PL) study. The synthesized nanoparticles are spherical particles with 30 nm size. The photoluminescence studies show the characteristic Eu3+ red emission. The PL study shows the intensity of the magnetic dipole transition ( 5 D0 \\to 7 F1 ) at 592 nm compared to that of the electronic dipole transition ( 5 D0 \\to 7 F2 ) at 615 nm. The nanomaterials can show significant application in various display devices and biomedical applications for tracking.

Cyto/hemocompatible magnetic hybrid nanoparticles (Ag2S-Fe3O4) with luminescence in the near-infrared region as promising theranostic materials.

PubMed

Hocaoglu, Ibrahim; Asik, Didar; Ulusoy, Gulen; Grandfils, Christian; Ojea-Jimenez, Isaac; Rossi, François; Kiraz, Alper; Doğan, Nurcan; Acar, Havva Yagci

2015-09-01

Small hybrid nanoparticles composed of highly biocompatible Ag2S quantum dots (QD) emitting in the near-infrared region and superparamagnetic iron oxide (SPION) are produced in a simple extraction method utilizing ligand exchange mechanism. Hybrid nanoparticles luminesce at the same wavelength as the parent QD, therefore an array of hybrid nanoparticles with emission between 840 and 912nm were easily produced. Such hybrid structures have (1) strong luminescence in the medical imaging window eliminating the autofluoresence of cells as effective optical probes, (2) strong magnetic response for magnetic targeting and (3) good cyto/hemocompatibility. An interesting size dependent cytotoxicity behavior was observed in HeLa and NIH/3T3 cell lines: smallest particles are internalized significantly more by both of the cell lines, yet showed almost no significant cytotoxicity in HeLa between 10 and 25μg/mL Ag concentration but were most toxic in NIH/3T3 cells. Cell internalization and hence the cytotoxicity enhanced when cells were incubated with the hybrid nanoparticles under magnetic field, especially with the hybrid nanoparticles containing larger amounts of SPION in the hybrid composition. These results prove them as effective optical imaging agents and magnetic delivery vehicles. Combined with the known advantages of SPIONs as a contrast agent in MRI, these particles are a step forward for new theranostics for multimode imaging and magnetic targeting. Copyright © 2015 Elsevier B.V. All rights reserved.

One-step microwave synthesis of photoluminescent carbon nanoparticles from sodium dextran sulfate water solution

NASA Astrophysics Data System (ADS)

Kokorina, Alina A.; Goryacheva, Irina Y.; Sapelkin, Andrei V.; Sukhorukov, Gleb B.

2018-04-01

Photoluminescent (PL) carbon nanoparticles (CNPs) have been synthesized by one-step microwave irradiation from water solution of sodium dextran sulfate (DSS) as the sole carbon source. Microwave (MW) method is very simple and cheap and it provides fast synthesis of CNPs. We have varied synthesis time for obtaining high luminescent CNPs. The synthesized CNPs exhibit excitation-dependent photoluminescent. Final CNPs water solution has a blue- green luminescence. CNPs have low cytotoxicity, good photostability and can be potentially suitable candidates for bioimaging, analysis or analytical tests.

Synthesis and characterization of luminescent aluminium selenide nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balitskii, O.A., E-mail: balitskii@electronics.wups.lviv.ua; Demchenko, P.Yu.; Mijowska, E.

Highlights: ► Synthesis procedure of size and sharp controlled Al{sub 2}Se{sub 3} nanocrystals is introduced. ► Obtained nanoparticles are highly crystalline of hexagonal wurtzite type. ► Colloidal Al{sub 2}Se{sub 3} nanocrystals are highly luminescent in the near UV spectral region. ► They can be implemented in light emitters/collectors, concurring with II–VI nanodots. -- Abstract: We propose the synthesis and characterization of colloidal aluminium selenide nanocrystals using trioctylphosphine as a solvent. The nanoparticles have several absorption bands in the spectral region 330–410 nm and are bright UV-blue luminescent, which is well demanded in light collecting and emitting devices, e.g. for tuningmore » their spectral characteristics to higher energy solar photons.« less

Perturbing Tandem Energy Transfer in Luminescent Heterobinuclear Lanthanide Coordination Polymer Nanoparticles Enables Real-Time Monitoring of Release of the Anthrax Biomarker from Bacterial Spores.

PubMed

Gao, Nan; Zhang, Yunfang; Huang, Pengcheng; Xiang, Zhehao; Wu, Fang-Ying; Mao, Lanqun

2018-06-05

Lanthanide-based luminescent sensors have been widely used for the detection of the anthrax biomarker dipicolinic acid (DPA). However, mainly based on DPA sensitization to the lanthanide core, most of them failed to realize robust detection of DPA in bacterial spores. We proposed a new strategy for reliable detection of DPA by perturbing a tandem energy transfer in heterobinuclear lanthanide coordination polymer nanoparticles simply constructed by two kinds of lanthanide ions, Tb 3+ and Eu 3+ , and guanosine 5'-monophosphate. This smart luminescent probe was demonstrated to exhibit highly sensitive and selective visual luminescence color change upon exposure to DPA, enabling accurate detection of DPA in complex biosystems such as bacterial spores. DPA release from bacterial spores on physiological germination was also successfully monitored in real time by confocal imaging. This probe is thus expected to be a powerful tool for efficient detection of bacterial spores in responding to anthrax threats.

Near-field thermal upconversion and energy transfer through a Kerr medium.

PubMed

Khandekar, Chinmay; Rodriguez, Alejandro W

2017-09-18

We present an approach for achieving large Kerr χ (3) -mediated thermal energy transfer at the nanoscale that exploits a general coupled-mode description of triply resonant, four-wave mixing processes. We analyze the efficiency of thermal upconversion and energy transfer from mid- to near-infrared wavelengths in planar geometries involving two slabs supporting far-apart surface plasmon polaritons and separated by a nonlinear χ (3) medium that is irradiated by externally incident light. We study multiple geometric and material configurations and different classes of intervening mediums-either bulk or nanostructured lattices of nanoparticles embedded in nonlinear materials-designed to resonantly enhance the interaction of the incident light with thermal slab resonances. We find that even when the entire system is in thermodynamic equilibrium (at room temperature) and under typical drive intensities ~ W/μm 2 , the resulting upconversion rates can approach and even exceed thermal flux rates achieved in typical symmetric and non-equilibrium configurations of vacuum-separated slabs. The proposed nonlinear scheme could potentially be exploited to achieve thermal cooling and refrigeration at the nanoscale, and to actively control heat transfer between materials with dramatically different resonant responses.

A double responsive smart upconversion fluorescence sensing material for glycoprotein.

PubMed

Guo, Ting; Deng, Qiliang; Fang, Guozhen; Yun, Yaguang; Hu, Yongjin; Wang, Shuo

2016-11-15

A novel strategy was developed to prepare double responsive smart upconversion fluorescence material for highly specific enrichment and sensing of glycoprotein. The novel double responsive smart sensing material was synthesized by choosing Horse radish peroxidase (HRP) as modal protein, the grapheme oxide (GO) as support material, upconversion nanoparticles (UCNPs) as fluorescence signal reporter, N-isopropyl acrylamide (NIPAAM) and 4-vinylphenylboronic acid (VPBA) as functional monomers. The structure and component of smart sensing material was investigated by transmission electron microscopy (TEM), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopic (XPS) and Fourier transform infrared (FTIR), respectively. These results illustrated the smart sensing material was prepared successfully. The recognition characterizations of smart sensing material were evaluated, and results showed that the fluorescence intensity of smart sensing material was reduced gradually, as the concentration of protein increased, and the smart sensing material showed selective recognition for HRP among other proteins. Furthermore, the recognition ability of the smart sensing material for glycoprotein was regulated by controlling the pH value and temperature. Therefore, this strategy opens up new way to construct smart material for detection of glycoprotein. Copyright © 2016 Elsevier B.V. All rights reserved.

Broadband dye-sensitized upconverting nanocrystals enabled near-infrared planar perovskite solar cells

NASA Astrophysics Data System (ADS)

Lai, Xuesen; Li, Xitao; Lv, Xinding; Zheng, Yan-Zhen; Meng, Fanli; Tao, Xia

2017-12-01

Extending the spectral absorption of perovskite solar cells (PSCs) from visible into near-infrared (NIR) range is a promising strategy to minimize non-absorption loss of solar photons and enhance the cell photovoltaic performance. Herein, we report on for the first time a viable strategy of incorporating IR806 dye-sensitized upconversion nanocrystals (IR806-UCNCs) into planar PSC for broadband upconversion of NIR light (800-1000 nm) into perovskite absorber-responsive visible emissions. A smart trick is firstly adopted to prepare hydrophilic IR806-UCNCs via a NOBF4 assisted two-step ligand-exchange that allows incorporating with perovskite precursor for in-situ growth of upconverting planar perovskite film. Unlike typically reported upconverting nanoparticles with narrow NIR absorption, the as-prepared IR806-UCNCs are able to harvest NIR light broadly and then transfer the captured energy to the UCNCs for an efficient visible upconversion. The IR806-UCNCs-incorporated cell exhibits a power conversion efficiency of 17.49%, corresponding to 29% increment from that of the pristine cell (13.52%). This strategy provides a feasible way to enable the most efficient harvesting of NIR sunlight for solar cells and other optoelectric devices.

Mechanisms of optical losses in the 5D4 and 5D3 levels in Tb3+ doped low silica calcium aluminosilicate glasses

NASA Astrophysics Data System (ADS)

dos Santos, J. F. M.; Terra, I. A. A.; Astrath, N. G. C.; Guimarães, F. B.; Baesso, M. L.; Nunes, L. A. O.; Catunda, T.

2015-02-01

Trivalent Tb-doped materials exhibit strong emission in the green and weak emission in the UV-blue levels. Usually, this behavior is attributed to the cross relaxation (CR) process. In this paper, the luminescence properties of Tb3+-doped low silica calcium aluminosilicate glasses are analyzed for UV (λexc = 325 nm) and visible (488 nm) excitations. Under 325 nm excitation, the intensity of green luminescence increases proportionally to Tb3+ concentration. However, the blue luminescence intensity is strongly reduced with the increase of concentration from 0.5-15.0 wt. %. In the case of 488 nm excitation, a saturation behavior of the green emission is observed at intensities two orders of magnitude smaller than expected for bleaching of the ground state population. Using a rate equation model, we showed that this behavior can be explained by an excited state absorption cross section two orders of magnitude larger than the ground state absorption. The blue emission is much weaker than expected from our rate equations (325 nm and 488 nm excitation). We concluded that only the CR process cannot explain the overall feature of measured luminescence quenching in the wide range of Tb3+ concentrations. Cooperative upconversion from a pair of excited ions (5D3:5D3 or 5D3:5D4) and other mechanisms involving upper lying states (4f5d, charge transfer, host matrix, defects, etc.) may play a significant role.

Photoluminescence of transparent glass-ceramics based on ZnO nanocrystals and co-doped with Eu3+, Yb3+ ions

NASA Astrophysics Data System (ADS)

Arzumanyan, Grigory M.; Kuznetsov, Evgeny A.; Zhilin, Aleksandr A.; Dymshits, Olga S.; Shemchuk, Daria V.; Alekseeva, Irina P.; Mudryi, Alexandr V.; Zhivulko, Vadim D.; Borodavchenko, Olga M.

2016-12-01

Glasses of the K2Osbnd ZnOsbnd Al2O3sbnd SiO2 system co-doped with Eu2O3 and Yb2O3 were prepared by the melt-quenching technique. Transparent zincite (ZnO) glass-ceramics were obtained by secondary heat-treatments at 680-860 °C. At 860 °C, traces of Eu oxyapatite appeared in addition to ZnO nanocrystals. The average crystal size obtained from the X-ray diffraction data was found to range between 14 and 35 nm. Absorption spectra of the initial glasses are composed of an absorption edge and absorption bands due to electronic transitions of Eu3+ ions. With heat-treatment, the absorption edge pronouncedly shifts to the visible spectral range. The luminescence properties of the glass and glass-ceramics were studied by measuring their excitation and emission spectra at 300, 78, and 4.2 K. Strong red emission of Eu3+ ions dominated by the 5D0-7F2 (612 nm) electric dipole transition was detected. Changes in the luminescence properties of the Eu3+-related excitation and emission bands were observed after heat-treatments at 680 °C and 860 °C. The ZnO nanocrystals showed both broad luminescence (400-850 nm) and free-exciton emission near 3.3 eV at room temperature. The upconversion luminescence spectrum of the initial glass was obtained under excitation of the 976 nm laser source.

Dual-emissive nanoarchitecture of lanthanide-complex-modified silica particles for in vivo ratiometric time-gated luminescence imaging of hypochlorous acid† †Electronic supplementary information (ESI) available: Characterization of the new compounds, Fig. S1–S12 and a video showing the real-time uptake and accumulation of HClO in living Daphnia magna using the RTLNP as a probe. See DOI: 10.1039/c6sc02243j Click here for additional data file. Click here for additional data file.

PubMed Central

Ma, Hua; Wang, Yuanxiu; Cong, Deyuan; Jiang, Yufei

2017-01-01

We have developed a ratiometric time-gated luminescence sensory system for in vivo imaging of hypochlorous acid (HClO) by preparing a dual-emissive nanoarchitecture of europium- and terbium-complex-modified silica nanoparticles. The design of this nanoarchitecture is based on our new finding that the strong, long-lived luminescence of the β-diketonate–Eu3+ complex can be rapidly and selectively quenched by HClO. Therefore, the β-diketonate–Eu3+ complex was decorated on the surface of the silica nanoparticles for responding to HClO, while a HClO-insensitive luminescent terbium complex was immobilized in the inner solid core of the nanoparticles to serve as an internal standard. This nanosensing probe combines the advantages of both ratiometric and time-gated detection modes to afford high accuracy and sensitivity. Upon exposure to HClO, the nanoprobe displayed a remarkable luminescence color change from red to green, and the intensity ratio of the green over the red luminescence (I 539/I 607) showed a rapid, sensitive and selective response to HClO. Additionally, the feasibility of using the nanoprobe for intracellular detection of exogenous and endogenous HClO and for real-time mapping of HClO in small laboratory animals has been demonstrated via ratiometric time-gated luminescence imaging microscopy. The results reveal that the constructed nanoarchitecture cloud is a favorable and useful sensing probe for the real-time imaging of HClO in vivo with high specificity and contrast. PMID:28451159

Development of luminescent pH sensor films for monitoring bacterial growth through tissue.

PubMed

Wang, Fenglin; Raval, Yash; Chen, Hongyu; Tzeng, Tzuen-Rong J; DesJardins, John D; Anker, Jeffrey N

2014-02-01

Although implanted medical devices (IMDs) offer many benefits, they are susceptible to bacterial colonization and infections. Such infections are difficult to treat because bacteria could form biofilms on the implant surface, which reduce antibiotics penetration and generate local dormant regions with low pH and low oxygen. In addition, these infections are hard to detect early because biofilms are often localized on the surface. Herein, an optical sensor film is developed to detect local acidosis on an implanted surface. The film contains both upconverting particles (UCPs) that serve as a light source and a pH indicator that alters the luminescence spectrum. When irradiated with 980 nm light, the UCPs produce deeply penetrating red light emission, while generating negligible autofluorescence in the tissue. The basic form of the pH indicator absorbs more of upconversion luminescence at 661 nm than at 671 nm and consequently the spectral ratio indicates pH. Implanting this pH sensor film beneath 6-7 mm of porcine tissue does not substantially affect the calibration curve because the peaks are closely spaced. Furthermore, growth of Staphylococcus epidermidis on the sensor surface causes a local pH decrease that can be detected non-invasively through the tissue. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Universal Multifunctional Nanoplatform Based on Target-Induced in Situ Promoting Au Seeds Growth to Quench Fluorescence of Upconversion Nanoparticles.

PubMed

Wu, Qiongqiong; Chen, Hongyu; Fang, Aijin; Wu, Xinyang; Liu, Meiling; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

2017-12-22

Construction of a new multifunctional chemo/biosensing platform for small biomolecules and tumor markers is of great importance in analytical chemistry. Herein, a novel universal multifunctional nanoplatform for biomolecules and enzyme activity detection was proposed based on fluorescence resonance energy transfer (FRET) between upconversion nanoparticles (UCNPs) and target-inducing enlarged gold nanoparticles (AuNPs). The reductive molecule such as H 2 O 2 can act as the reductant to reduce HAuCl 4 , which will make the Au seeds grow. The enlarged AuNPs can effectively quench the fluorescence of UCNPs owing to the good spectral overlap between the absorption band of the AuNPs and the emission band of the UCNPs. Utilizing the FRET between the UCNPs and enlarged AuNPs, good linear relationship between the fluorescence of UCNPs and the concentration of H 2 O 2 can be found. Based on this strategy, H 2 O 2 related molecules such as l-lactate, glucose, and uric acid can also be quantified. On the basis of UCNPs and PVP/HAuCl 4 , a general strategy for other reductants such as ascorbic acid (AA), dopamine (DA), or enzyme activity can be established. Therefore, the universal multifunctional nanoplatform based on UCNPs and the target-inducing in situ enlarged Au NPs will show its potential as a simple method for the detection of some life related reductive molecules, enzyme substrates, as well as enzyme activity.

Upconversion nanoparticle as elemental tag for the determination of alpha-fetoprotein in human serum by inductively coupled plasma mass spectrometry.

PubMed

Liu, Zhengru; Yang, Bin; Chen, Beibei; He, Man; Hu, Bin

2016-12-19

Upconversion nanoparticles (UCNPs) have received increasing attention due to their unique optical properties. Recognizing that UCNPs are lanthanide-doped nanoparticles, we incorporated UCNPs into an immunoassay with inductively coupled plasma mass spectrometry (ICP-MS) detection for the determination of specific proteins, e.g., alpha-fetoprotein (AFP). The sensitivity of the assay was enhanced because of the ICP-MS detection of UCNPs that contained large numbers of lanthanide elemental tags. Conjugates of UCNPs and antibodies were prepared and the morphology of the conjugates was characterized by transmission electron microscopy. After a sandwich immunoreaction, the AFP was determined by the ICP-MS analysis of UCNPs. Under the optimized conditions, a limit of detection (3σ) of 0.31 ng mL -1 based on 89 Y signal and 0.22 ng mL -1 based on 174 Yb signal was obtained for AFP, with a dynamic range of 0.5-35 ng mL -1 and a relative standard deviation of 4.8% (c = 5 ng mL -1 , n = 9). The developed method was applied to the determination of AFP in human serum and the recovery for the spiked sample was in the range of 98.6-123%. The proposed method is simple, rapid, selective and sensitive, and has a good tolerance for the complex biological matrix, indicating great potential for the application of UCNP in biological research as an elemental tag.

Effect of B2O3 on luminescence of erbium doped tellurite glasses.

PubMed

Shen, Xiang; Nie, Qiuhua; Xu, Tiefeng; Dai, Shixun; Wang, Xunsi

2007-02-01

The B2O3 was introduced into the Er3+ doped TeO2-ZnO-Na2O glass to increase the phonon energy of the host. The effect of B2O3 on the non-radiative rate of the 4I11/2-->4I13/2 transition of Er3+, the lifetime of the 4I11/2 and 4I13/2 levels, the green and red upconversion emissions intensity, and the 4I13/2-->4I15/2 emission intensity was discussed. The results show that the phonon energy of boro-tellurite glass is close to that of germanate glass and is quite smaller than that of borate glass. The lifetime of 4I11/2 level and the upconversion emissions decrease with increasing B2O3 concentration. The higher OH group concentration presented in the boro-tellurite glass may shorten the lifetime of 4I13/2 level and also reduce the quantum efficiency of 4I13/2-->4I15/2 emission. The future dehydrating procedures are suggested to enhance the efficiency of amplification at 1.5 microm band.

Optical properties and mechanisms in Cr3+, Bi3+-codoped oxide-based spinel nanoparticles

NASA Astrophysics Data System (ADS)

Pellerin, Morgane; Coelho-Diogo, Cristina; Bonhomme, Christian; Touatib, Nadia; Binet, Laurent; Gourier, Didier; Ueda, Jumpei; Tanabe, Setsuhisa; Viana, Bruno; Chanéac, Corinne

2017-02-01

At the nanoscale, the ZnGa2O4 spinel doped with chromium (III) is an interesting material for in vivo optical imaging due to its bright red persistent luminescence after UV and visible excitation. Moreover its persistent luminescent properties can be improved with the incorporation of bismuth (III) as a co-dopant without any structure changes. The nanoparticles are synthesized by soft chemistry using microwave heating in aqueous media. These very small sized nanophosphors (around 10 nm) present interesting long lasting persistent luminescence after annealing at 1000°C and they can be excited both under UV and under visible LED excitation. In this work we try to understand the mechanisms of the persistent luminescent properties of such nanomaterials. Thermoluminescence is performed to investigate trapping and detrapping processes as well as trap distribution. The chromium local environment is studied by Electron Paramagnetic Resonance. 71Ga Nuclear Magnetic Resonance is used to get information on the gallium ions repartition (tetrahedral or octahedral site) in the structure. Comparison of optical properties versus local structure increases the understanding of the persistent luminescence mechanism and gives insights to the new modalities for their use as nanoprobes for in vivo imaging.

Synthesis and Luminescence Properties of Core/Shell ZnS:Mn/ZnO Nanoparticles.

PubMed

Jiang, Daixun; Cao, Lixin; Liu, Wei; Su, Ge; Qu, Hua; Sun, Yuanguang; Dong, Bohua

2009-01-01

In this paper the influence of ZnO shell thickness on the luminescence properties of Mn-doped ZnS nanoparticles is studied. Transmission electron microscopy (TEM) images showed that the average diameter of ZnS:Mn nanoparticles is around 14 nm. The formation of ZnO shells on the surface of ZnS:Mn nanoparticles was confirmed by X-ray diffraction (XRD) patterns, high-resolution TEM (HRTEM) images, and X-ray photoelectron spectroscopy (XPS) measurements. A strong increase followed by a gradual decline was observed in the room temperature photoluminescence (PL) spectra with the thickening of the ZnO shell. The photoluminescence excitation (PLE) spectra exhibited a blue shift in ZnO-coated ZnS:Mn nanoparticles compared with the uncoated ones. It is shown that the PL enhancement and the blue shift of optimum excitation wavelength are led by the ZnO-induced surface passivation and compressive stress on the ZnS:Mn cores.

Amine-functionalized lanthanide-doped zirconia nanoparticles: optical spectroscopy, time-resolved fluorescence resonance energy transfer biodetection, and targeted imaging.

PubMed

Liu, Yongsheng; Zhou, Shanyong; Tu, Datao; Chen, Zhuo; Huang, Mingdong; Zhu, Haomiao; Ma, En; Chen, Xueyuan

2012-09-12

Ultrasmall inorganic oxide nanoparticles doped with trivalent lanthanide ions (Ln(3+)), a new and huge family of luminescent bioprobes, remain nearly untouched. Currently it is a challenge to synthesize biocompatible ultrasmall oxide bioprobes. Herein, we report a new inorganic oxide bioprobe based on sub-5 nm amine-functionalized tetragonal ZrO(2)-Ln(3+) nanoparticles synthesized via a facile solvothermal method and ligand exchange. By utilizing the long-lived luminescence of Ln(3+), we demonstrate its application as a sensitive time-resolved fluorescence resonance energy transfer (FRET) bioprobe to detect avidin with a record-low detection limit of 3.0 nM. The oxide nanoparticles also exhibit specific recognition of cancer cells overexpressed with urokinase plasminogen activator receptor (uPAR, an important marker of tumor biology and metastasis) and thus may have great potentials in targeted bioimaging.

Structure and properties of nanoparticles fabricated by laser ablation of Zn metal targets in water and ethanol

NASA Astrophysics Data System (ADS)

Svetlichnyi, V. A.; Lapin, I. N.

2013-10-01

Size characteristics, structure, and spectral and luminescent properties of nanoparticles fabricated by laser ablation of zinc metal targets in water and ethanol are experimentally investigated upon excitation by Nd:YAG-laser radiation (1064 nm, 7 ns, and 15 Hz). It is demonstrated that zinc oxide nanoparticles with average sizes of 10 nm (in water) and 16 nm (in ethanol) are formed in the initial stage as a result of ablation. The kinetics of the absorption and luminescence spectra, transmission electron microscopy, and x-ray structural analysis demonstrate that during long storage of water dispersions and their drying, nanoparticles efficiently interact with carbon dioxide gas of air that leads to the formation of water-soluble Zn(CO3)2(OH)6. In ethanol, Zn oxidation leads to the formation of stable dispersions of ZnO nanoparticles with 99% of the wurtzite phase; in this case, the fluorescence spectra of ZnO nanoparticles change with time, shifting toward longer wavelength region from 550 to 620 nm, which is caused by the changed nature of defects.