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Sample records for organic-inorganic sers nanoparticles

  1. Electron Microscopy Localization and Characterization of Functionalized Composite Organic-Inorganic SERS Nanoparticles on Leukemia Cells

    PubMed Central

    Koh, Ai Leen; Shachaf, Catherine M.; Elchuri, Sailaja; Nolan, Garry P.; Sinclair, Robert

    2008-01-01

    We demonstrate the use of electron microscopy as a powerful characterization tool to identify and locate antibody-conjugated composite organic-inorganic (COINs) surface enhanced Raman scattering (SERS) nanoparticles on cells. U937 leukemia cells labeled with antibody CD54-conjugated COINs were characterized in their native, hydrated state using wet Scanning Electron Microscopy (SEM) and in their dehydrated state using high-resolution SEM. In both cases, the backscattered electron detector (BSE) was used to detect and identify the silver constituents in COINs due to its high sensitivity to atomic number variations within a specimen. The imaging and analytical capabilities in the SEM were further complemented by higher resolution Transmission Electron Microscope (TEM) images and Scanning Auger Electron Spectroscopy (AES) data to give reliable and high-resolution information about nanoparticles and their binding to cell surface antigens. PMID:18995965

  2. Air stable organic-inorganic nanoparticles hybrid solar cells

    SciTech Connect

    Qian, Lei; Yang, Jihua; Xue, Jiangeng; Holloway, Paul H.

    2015-09-29

    A solar cell includes a low work function cathode, an active layer of an organic-inorganic nanoparticle composite, a ZnO nanoparticle layer situated between and physically contacting the cathode and active layers; and a transparent high work function anode that is a bilayer electrode. The inclusion of the ZnO nanoparticle layer results in a solar cell displaying a conversion efficiency increase and reduces the device degradation rate. Embodiments of the invention are directed to novel ZnO nanoparticles that are advantageous for use as the ZnO nanoparticle layers of the novel solar cells and a method to prepare the ZnO nanoparticles.

  3. Dendrimer-based organic/inorganic hybrid nanoparticles in biomedical applications

    NASA Astrophysics Data System (ADS)

    Shen, Mingwu; Shi, Xiangyang

    2010-09-01

    This review reports some recent advances on the synthesis, self-assembly, and biofunctionalization of various dendrimer-based organic/inorganic hybrid nanoparticles (NPs) for various biomedical applications, including but not limited to protein immobilization, gene delivery, and molecular diagnosis. In particular, targeted molecular imaging of cancer using dendrimer-based organic/inorganic hybrid NPs will be introduced in detail.

  4. Synthesis of hybrid organic-inorganic near-IR responsive magnetic nanoparticles for cancer theragnosis

    NASA Astrophysics Data System (ADS)

    Bang, Doyeon; Lee, Taeksu; Choi, Jihye; Park, Joseph; Kang, Byunghoon; Huh, Yong-Min; Haam, Seungjoo

    2012-10-01

    Hybrid organic-inorganic near-infrared responsive magnetic nanoparticles were synthesized for theragnosis combined with localized therapy. In detail, inorganic super-paramagnetic nanoparticles were embedded inside organic polyaniline matrix, which enables localized photothermal therapy upon NIR illumination under intracellular acidic/oxidative condition. In this structure, super-paramagnetic nanoparticle works as MRI contrast agent, that enables the visualization of a tumor and polyaniline works for near-infrared responsive tumor ablation.

  5. Hybrid organic-inorganic nanomaterials based on polythiophene dendronized nanoparticles.

    PubMed

    Advincula, Rigoberto C

    2006-06-21

    In this work, the synthesis, characterization, and applications of branched oligothiophene dendrons that act as electroactive surfactants for the capping of Au metal nanoparticles and CdSe quantum dots are described. Two distinct methods have been employed for synthesis: a ligand exchange process and a direct-capping synthesis approach. The coverage of the dendrons per nanocrystal, the nature of the surface coordination interactions, and energy transfer interactions were studied in detail using UV-vis absorbance, FT-IR, AFM, TEM, and photoluminescence spectroscopy. The competition/displacement in ligand metathesis is highlighted by the size of the dendron and nature of binding on semiconductor nanocrystals. In the other system using the direct capping method, the size of the Au nanoparticle is mediated by the dimensions of the ligand, i.e. alkyl chain spacer and dendron branching or size. These hybrid dendron/nanoparticle complexes are generally very soluble and stable in non-polar solvents. They exhibit energy transfer, surface plasmon resonance effects, and photoinduced charge transfer interactions between the metal/semiconductor and conjugated ligands. Adsorption on mica and graphite surfaces was observed. A one-layer photovoltaic cell was fabricated to demonstrate the potential for device applications.

  6. Organic-inorganic materials containing nanoparticles of zirconium hydrophosphate for baromembrane separation

    NASA Astrophysics Data System (ADS)

    Dzyazko, Yuliya S.; Rozhdestvenskaya, Ludmila M.; Zmievskii, Yu G.; Vilenskii, Alexander I.; Myronchuk, Valerii G.; Kornienko, Ludmila V.; Vasilyuk, Sergey V.; Tsyba, Nikolay N.

    2015-02-01

    Organic-inorganic membranes were obtained by stepwise modification of poly(ethyleneterephthalate) track membrane with nanoparticles of zirconium hydrophosphate. The modifier was inserted inside pores of the polymer, a size of which is 0.33 μm. Inner active layer was formed by this manner. Evolution of morphology and functional properties of the membranes were investigated using methods of porosimetry, potentiometry and electron microscopy. The nanoparticles (4 to 10 nm) were found to form aggregates, which block pores of the polymer. Pores between the aggregates (4 to 8 nm) as well as considerable surface charge density provide significant transport numbers of counter ions (up to 0.86 for Na+). The materials were applied to baromembrane separation of corn distillery. It was found that precipitate is formed mainly inside the pores of the pristine membrane. In the case of the organic-inorganic material, the deposition occurs onto the outer surface and can be removed by mechanical way. Location of the active layer inside membranes protects it against damage.

  7. Direct control of the spatial arrangement of gold nanoparticles in organic-inorganic hybrid superstructures.

    PubMed

    Hermes, Jens P; Sander, Fabian; Peterle, Torsten; Cioffi, Carla; Ringler, Philippe; Pfohl, Thomas; Mayor, Marcel

    2011-04-04

    The directed assembly of gold nanoparticles is essential for their use in many kinds of applications, such as electronic devices, biological labels, and sensors. Herein an atomic alteration in the molecular structure of ligand-stabilized gold nanoparticles that can shift the interparticle distance up to 1 nm upon covalent coupling to organic-inorganic superstructures is presented. Gold nanoparticles are stabilized by two octadentate thioether ligands and have a mean diameter of 1.1 nm. The ligands contain a central rigid rod varying in length and terminally functionalized with a protected acetylene. The two peripheral functional groups on each particle enable the directed assembly of nanoparticles to dimers, trimers, and tetramers by oxidative acetylene coupling. This is a wet chemical protocol resulting in covalently bound nanoparticles. These organic-inorganic hybrid superstructures are analyzed by transmission electron microscopy, small angle X-ray scattering, and UV/vis spectroscopy. The focus of the comparison here is the subunit, which is anchoring the bridgehead, either a pyridine or benzene moiety. The pyridine-based ligands reflect the calculated length of the rigid-rod spacer in their interparticle distances in the obtained hybrid structures. This suggests a perpendicular arrangement that results from the coordination of the pyridine's lone pair to the gold surface. An atomic variation in the ligand's center leads to smaller interparticle distances in the case of hybrid structures obtained from benzene ligands. This large difference in the spatial arrangement suggests a tangential arrangement of the interparticle bridging structure in the latter case. Consequently a rather flat arrangement parallel to the particle surface must be assumed for the central benzene unit of the benzene-based ligand.

  8. Bridged polysilsesquioxanes: Hybrid organic-inorganic materials as fuel cell polyelectrolyte membranes and functional nanoparticles

    NASA Astrophysics Data System (ADS)

    Khiterer, Mariya

    2007-05-01

    This dissertation describes the design, fabrication, and characterization of organic-inorganic hybrid materials. Several classes of bridged polysilsesquioxanes are presented. The first class is a membrane material suitable for fuel cell technology as a proton conducting polyelectrolyte. The second class includes hybrid nanoparticles for display device applications and chromatographic media. Chapter 1 is an introduction to hybrid organic-inorganic materials. Sol-gel chemistry is discussed, followed by a survey of prominent examples of silica hybrids. Examples of physical organic-silica blends and covalent organo-silicas, including ORMOCERSRTM, polyhedral oligomeric silsesquioxanes, and bridged polysilsesquioxanes are discussed. Bridged polysilsesquioxanes are described in great detail. Monomer synthesis, sol-gel chemistry, processing, characterization, and physical properties are included. Chapter 2 describes the design of polyelectrolyte bridged polysilsesquioxane membranes. The materials contain covalently bound sulfonic acid groups originating from the corresponding disulfides. These organic-inorganic hybrid materials integrate a network supporting component which is systematically changed to fine-tune their physical properties. The membranes are characterized as PEM fuel cell electrolytes, where proton conductivities of 4-6 mS cm-1 were measured. In Chapter 3 techniques for the preparation of bridged polysilsesquioxane nanoparticles are described. An inverse water-in-oil microemulsion polymerization method is developed to prepare cationic nanoparticles, including viologen-bridged materials with applications in electrochromic display devices. An aqueous ammonia system is used to prepare neutral nanoparticles containing hydrocarbon bridging groups, which have potential applications as chromatographic media. Chapter 4 describes electrochromic devices developed in collaboration with the Heflin group of Virginia Tech, which incorporate viologen bridged nanoparticles

  9. Improvement in open circuit voltage of MEHPPV-FeS2 nanoparticle based organic inorganic hybrid solar cell

    NASA Astrophysics Data System (ADS)

    Layek, Animesh; Middya, Somnath; Ray, Partha Pratim

    2013-02-01

    In this study we have synthesized high quality FeS2 nanoparticles by solvothermal route and was applied as semiconducting acceptor in MEHPPV:FeS2 nanoparticle based organic inorganic hybrid solar cells. The open circuit voltage improved from 0.64V to 0.72V of the device due to modification of band gap of donor material by introducing nanoparticles.

  10. Fundamental understanding of the synthesis and tribological behavior of organic-inorganic nanoparticles

    NASA Astrophysics Data System (ADS)

    Verma, Arpana

    The objective of this doctoral research is to design, synthesize, and test an advanced lubricant additive using novel active nanostructures of inorganic layered solid lubricant particles (MoS2), integrated and encapsulated with organic molecules, namely triglycerides and phospholipids, respectively. It was hypothesized that this combination can uniquely respond under severe boundary lubrication conditions (where high frictional losses exist). These organic-inorganic nanoparticles were synthesized using a top-down nanomanufacturing process, commonly known as high-energy ball milling or mechanical milling. It was performed in the presence of ambient air followed by organic molecules (triglycerides) to produce nanoparticles with controlled morphologies and surface properties. SEM, particle size analysis, and XRD showed a particle size reduction up to 100 nm and a grain size of 6 nm. TEM showed that after air milling for 48 hrs, agglomerated clusters of quasi-spherical nanoparticles of MoS2 were formed. HRTEM shows that the inter-planar defects and milling assisted shearing between the platelets caused the resultant curling of the planes, forming these unique nanostructures. Further milling of these clusters for 48 hrs in an organic medium (triglycerides) produced mono-dispersed quasi-spherical nanoparticles (<100 nm size). Surface analysis showed the presence of hydrocarbons, COO- molecules on the deagglomerated nanoparticles indicating a chemisorbed capping layer. A capping layer was also confirmed by zeta potential analysis. Tribological studies using pin-on-disk and four-ball tests showed that this novel active material can significantly reduce friction and wear. The coefficient of friction was reduced in pin-on-disk from 0.15 to 0.04 when these nanoparticles were mixed with the base oil. Similarly, in four-ball tests, significant reduction in coefficient of friction (0.06-0.07) and wear (0.47 mm) reduction were observed. To understand the underlying mechanism of

  11. Organic-inorganic hybrid nanoparticles: surface characteristics and interactions with a polyester resin.

    PubMed

    Jesson, David A; Abel, Marie-Laure; Hay, John N; Smith, Paul A; Watts, John F

    2006-05-23

    Organic-inorganic hybrid nanoparticles, derived from silica precursors with different organic functionalities (methyl, ethyl, vinyl, and phenyl) synthesized via a modified Stöber method have been investigated. These particles are intended as modifiers for polymers and polymer matrix composites. Therefore, the characteristics of a polyester matrix have also been determined, and the likely interactions with the particles have been proposed. Particles have been characterized using inverse gas chromatography (IGC), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy (FT-IR). The particles show two different sets of characteristics, with methyl, ethyl, and vinyl modified silicas showing one type of behavior and the phenyl modified silica behaving rather differently. The methyl, ethyl, and vinyl groups exhibit the appearance of uniform coverage, as they are comparatively small and tightly packed, which will prevent interaction of matrix resin with retained silanol groups. The phenyl group, which is comparatively large, is not able to pack as closely, which results in a reduction of the presence and availability of silanol groups, compared to an unmodified fumed silica, but not complete inaccessibility as far as the matrix resin is concerned.

  12. Electrophoretic deposition of organic/inorganic composite coatings containing ZnO nanoparticles exhibiting antibacterial properties.

    PubMed

    Karbowniczek, Joanna; Cordero-Arias, Luis; Virtanen, Sannakaisa; Misra, Superb K; Valsami-Jones, Eugenia; Tuchscherr, Lorena; Rutkowski, Bogdan; Górecki, Kamil; Bała, Piotr; Czyrska-Filemonowicz, Aleksandra; Boccaccini, Aldo R

    2017-08-01

    To address one of the serious problems associated with permanent implants, namely bacterial infections, novel organic/inorganic coatings containing zinc oxide nanoparticles (nZnO) are proposed. Coatings were obtained by electrophoretic deposition (EPD) on stainless steel 316L. Different deposition conditions namely: deposition times in the range 60-300s and applied voltage in the range 5-30V as well as developing a layered coating approach were studied. Antibacterial tests against gram-positive Staphylococcus aureus and gram-negative Salmonella enteric bacteria confirmed the activity of nZnO to prevent bacterial growth. Coatings composition and morphology were analyzed by thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. Moreover, the corrosion resistance was analyzed by evaluation of the polarization curves in DMEM at 37°C, and it was found that coatings containing nZnO increased the corrosion resistance compared to the bare substrate. Considering all results, the newly developed coatings represent a suitable alternative for the surface modification of metallic implants. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Organic-inorganic hybrid thin film solar cells using conducting polymer and gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Hwan Jung, Hyung; Ho Kim, Dong; Su Kim, Chang; Bae, Tae-Sung; Bum Chung, Kwun; Yoon Ryu, Seung

    2013-05-01

    We employed poly(styrenesulfonate)-doped poly (3,4-ethylenedioxythiophene) (PEDOT:PSS) as a p-layer on textured fluorine-tin-oxide (FTO) glass in pin-type hydrogenated amorphous silicon solar cells (a-Si:H SCs). An amorphous tungsten oxide (WO3) layer and gold nanoparticles (Au-NPs) 10 nm in size were included to prevent the degradation and to increase short-circuit current by the Plasmon effect, respectively, between the PEDOT:PSS and intrinsic-Si layer. The energy band between PEDOT:PSS and WO3 was meaningfully adjusted by Au-NPs. The p-type PEDOT:PSS layer in these organic-inorganic hybrid a-Si:H SCs results in an increased conversion efficiency from ˜2.42% to ˜5.49% and an increased open-circuit voltage from ˜0.29 V to ˜0.56 V. PEDOT:PSS on textured FTO glass is sufficiently showing that it can replace the p-type Si layer in pin-type a-Si:H SCs.

  14. Resonant Infrared Matrix-Assisted Pulsed Laser Evaporation Of Inorganic Nanoparticles And Organic/Inorganic Hybrid Nanocomposites

    SciTech Connect

    Pate, Ryan; Lantz, Kevin R.; Stiff-Roberts, Adrienne D.; Dhawan, Anuj; Vo-Dinh, Tuan

    2010-10-08

    In this research, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been used to deposit different classes of inorganic nanoparticles, including bare, un-encapsulated ZnO and Au nanoparticles, as well as ligand-encapsulated CdSe colloidal quantum dots (CQDs). RIR-MAPLE has been used for thin-film deposition of different organic/inorganic hybrid nanocomposites using some of these inorganic nanoparticles, including CdSe CQD-poly[2-methoxy-5-(2'-ethylhexyloxy )-1,4-(1-cyanovinylene)phenylene](MEH-CN-PPV) nanocomposites and Au nanoparticle-poly(methyl methacrylate)(PMMA) nanocomposites. The unique contribution of this research is that a technique is demonstrated for the deposition of organic-based thin-films requiring solvents with bond energies that do not have to be resonant with the laser energy. By creating an emulsion of solvent and ice in the target, RIR-MAPLE using a 2.94 {mu}m laser can deposit most material systems because the hydroxyl bonds in the ice component of the emulsion matrix are strongly resonant with the 2.94 {mu}m laser. In this way, the types of materials that can be deposited using RIR-MAPLE has been significantly expanded. Furthermore, materials with different solvent bond energies can be co-deposited without concern for material degradation and without the need to specifically tune the laser energy to each material solvent bond energy, thereby facilitating the realization of organic/inorganic hybrid nanocomposite thin-films. In addition to the structural characterization of the inorganic nanoparticle and hybrid nanocomposite thin-films deposited using this RIR-MAPLE technique, optical characterization is presented to demonstrate the potential of such films for optoelectronic device applications.

  15. Silica nanoparticles treated by cold atmospheric-pressure plasmas improve the dielectric performance of organic-inorganic nanocomposites.

    PubMed

    Yan, Wei; Han, Zhao Jun; Phung, B Toan; Ostrikov, Kostya Ken

    2012-05-01

    We report on the application of cold atmospheric-pressure plasmas to modify silica nanoparticles to enhance their compatibility with polymer matrices. Thermally nonequilibrium atmospheric-pressure plasma is generated by a high-voltage radio frequency power source operated in the capacitively coupled mode with helium as the working gas. Compared to the pure polymer and the polymer nanocomposites with untreated SiO(2), the plasma-treated SiO(2)-polymer nanocomposites show higher dielectric breakdown strength and extended endurance under a constant electrical stress. These improvements are attributed to the stronger interactions between the SiO(2) nanoparticles and the surrounding polymer matrix after the plasma treatment. Our method is generic and can be used in the production of high-performance organic-inorganic functional nanocomposites.

  16. Morphology and properties of a hybrid organic-inorganic system: Al nanoparticles embedded into CuPc thin film

    SciTech Connect

    Molodtsova, O. V.; Babenkov, S. V.; Aristova, I. M.; Vilkov, O. V.; Aristov, V. Yu.

    2014-04-28

    The evolution of the morphology and the electronic structure of the hybrid organic-inorganic system composed of aluminum nanoparticles (NPs) distributed in an organic semiconductor matrix—copper phthalocyanine (CuPc)—as a function of nominal aluminum content was studied by transmission electron microscopy and by photoemission spectroscopy methods. The aluminum atoms deposited onto the CuPc surface diffuse into the organic matrix and self-assemble to NPs in a well-defined manner with a narrow diameter distribution, which depends on the amount of aluminum that is evaporated onto the CuPc film. We find clear evidence of a charge transfer from Al to CuPc and we have been able to determine the lattice sites where Al ions sit. The finally at high coverage about 64 Å the formation of metallic aluminum overlayer on CuPc thin film takes place.

  17. Absorption and scattering effects by silver nanoparticles near the interface of organic/inorganic semiconductor tandem films

    NASA Astrophysics Data System (ADS)

    Nemes, Coleen T.; Vijapurapu, Divya K.; Petoukhoff, Christopher E.; Cheung, Gary Z.; O'Carroll, Deirdre M.

    2013-08-01

    nanoparticles placed near an organic/inorganic interface can be employed for light management in tandem or hybrid organic/inorganic thin-film semiconductor configurations for solar energy harvesting applications or light detection applications.

  18. Gold nanoparticles embedded in organic/inorganic hybrid matrix: electrical and electrochemical behavior (withdrawal notice)

    NASA Astrophysics Data System (ADS)

    Moreira, Sandra D. F. C.; Silva, J. P. B.; Silva, Carlos J. R.; Capan, I.; Gomes, M. J. M.; Costa, Manuel F. M.

    2013-05-01

    Gold nanoparticles (AuNPs) with different diameters, from 3 to 32 nm, were immobilized in amine-alcohol-silicate matrix by mixing a preformed nanoparticle colloid with the precursors of amine-alcohol-silicate (AAs) prior to the solgel transition. These nanocomposites show high optical quality and optical features dictated by the size of the nanoparticle dopants but also present a high degree of flexibility which can largely enhance the range of practical applications. The current-voltage, impedance and capacitance-voltage characteristics of these materials have been measured. The electrochemical and impedimetric results reveal that AuNPs with different sizes give different signals, thus providing useful information that allows the employment of AuNPs in electrochemical biosensors. Capacitance- voltage measurements showed that these composites embedded AuNPs exhibited a large hysteresis window of 2.4V which indicates the possibility of charge storage in the Au nanoparticles embedded AAs hybrids.

  19. Optical properties of LaF3:Er,Yb nanoparticle-doped organic-inorganic hybrid material.

    PubMed

    Li, Tong; Zhang, Dan; Chen, Cong; Bo, Shuhui; Zhang, Daming

    2010-03-01

    Oleic acid (OA)-modified LaF3:Er,Yb nanoparticle-doped organic-inorganic hybrid material (OIHM) was prepared. The absorption spectrum and photoluminescence spectrum were analyzed. The full width at half maximum (FWHM) of the photoluminescence spectrum was about 83 nm. The Judd-Ofelt theory was used to analyze the absorption spectrum of Er3+ and obtain the intensity parameters: omega2 = 2.11 x 10(-20) cm2, omega4 = 0.78 x 10(-200 cm2, omega6 = 0.56 x 10(-20)cm2. The line strengths predict spontaneous transition probabilities, and the radiative lifetimes are calculated with the Judd-Ofelt intensity parameters. The calculated radiative lifetime of the excited 4I13/2 state of Er3+ is 13.34 ms. Based on the parameters we calculated, OA-modified LaF3:Er,Yb nanoparticle-doped OIHM is a potential material for polymeric optical waveguide amplifiers.

  20. Aggregation of dipolar molecules in SiO2 hybrid organic-inorganic films: use of silver nanoparticles as inhibitors of molecular aggregation

    NASA Astrophysics Data System (ADS)

    Franco, Alfredo; García-Macedo, Jorge; Brusatin, Giovanna; Guglielmi, Massimo

    2013-04-01

    The technological implementation of hybrid organic-inorganic materials in second order nonlinear optical photonic devices depends strongly on the ability of the host matrixes to contain high loads of dipolar molecules without aggregation. Some organic molecules are often used to diminish the attracting interactions between dipolar molecules in such kind of materials, but their efficiency as inhibitors of molecular aggregation is limited by their polarizability. In this work, we report the use of silver nanoparticles as inhibitors of molecular aggregation in hybrid organic-inorganic films doped with dipolar molecules. The large polarizability of the silver nanoparticles makes them ideal moieties for the inhibition of the electrostatic interactions between dipolar nonlinear optical molecules. The average size of the silver nanoparticles in this work was 70.5 nm in diameter, they were synthesized using silver nitrate (AgNO3) as precursor and aminoethylaminopropyltrimethoxysilane as reducing agent. These nanoparticles were immersed in SiO2 hybrid organic-inorganic sol-gel films doped with dipolar chromophores to study their effect as inhibitors of dipolar chromophores aggregation. The presence of the silver nanoparticles in the solid films was confirmed by transmission electronic microscopy and UV-Visible spectroscopy. UV-Visible spectroscopy was also used to monitor the dipolar chromophores aggregation in the SiO2 films. We found that, at room temperature, silver nanoparticles are good inhibiting chromophores aggregation in comparison with the performance of organic inhibitors.

  1. Organic-inorganic hybrid materials: nanoparticle containing organogels with myriad applications.

    PubMed

    Peveler, William J; Bear, Joseph C; Southern, Paul; Parkin, Ivan P

    2014-11-28

    The synthesis of hybrid inorganic-organic materials from a single-component organogelator is reported. Varied functional inorganic materials were included and the resultant physico-chemical properties of the gels are presented. These materials are quick, versatile, can be cast into virtually any form, and the nanoparticles are easily reclaimed.

  2. Enzymatically degradable hybrid organic-inorganic bridged silsesquioxane nanoparticles for in vitro imaging

    NASA Astrophysics Data System (ADS)

    Fatieiev, Y.; Croissant, J. G.; Julfakyan, K.; Deng, L.; Anjum, D. H.; Gurinov, A.; Khashab, N. M.

    2015-09-01

    We describe biodegradable bridged silsesquioxane (BS) composite nanomaterials with an unusually high organic content (ca. 50%) based on oxamide components mimicking amino acid biocleavable groups. Unlike most bulk BS materials, the design of sub-200 nm nearly monodisperse nanoparticles (NPs) was achieved. These enzymatically degradable BS NPs were further tested as promising imaging nanoprobes.We describe biodegradable bridged silsesquioxane (BS) composite nanomaterials with an unusually high organic content (ca. 50%) based on oxamide components mimicking amino acid biocleavable groups. Unlike most bulk BS materials, the design of sub-200 nm nearly monodisperse nanoparticles (NPs) was achieved. These enzymatically degradable BS NPs were further tested as promising imaging nanoprobes. Electronic supplementary information (ESI) available: Detailed synthetic procedure, experimental procedure and Fig. S1-15. See DOI: 10.1039/c5nr03065j

  3. Size-controlled hydroxyapatite nanoparticles as self-organized organic-inorganic composite materials.

    PubMed

    Rusu, Viorel Marin; Ng, Chuen-How; Wilke, Max; Tiersch, Brigitte; Fratzl, Peter; Peter, Martin G

    2005-09-01

    This paper presents some results concerning the size-controlled hydroxyapatite nanoparticles obtained in aqueous media in a biopolymer matrix from soluble precursors salts. Taking the inspiration from nature, where composite materials made of a polymer matrix and inorganic fillers are often found, e.g. bone, shell of crustaceans, shell of eggs, etc., the feasibility on making composite materials containing chitosan and nanosized hydroxyapatite was investigated. A stepwise co-precipitation approach was used to obtain different types of composites by means of different ratio between components. The synthesis of hydroxyapatite was carried out in the chitosan matrix from calcium chloride and sodium dihydrogenphosphate in alkaline solutions at moderate pH of 10-11 for 24 h. Our research is focused on studying and understanding the structure of this class of composites, aiming at the development of novel materials, controlled at the nanolevel scale. The X-ray diffraction technique was employed in order to study the kinetic of hydroxyapatite formation in the chitosan matrix as well as to determine the HAp crystallite sizes in the composite samples. The hydroxyapatite synthesized using this route was found to be nano-sized (15-50 nm). Moreover, applying an original approach to analyze the (002) XRD diffraction peak profile of hydroxyapatite by using a sum of two Gauss functions, the bimodal distribution of nanosized hydroxyapatite within the chitosan matrix was revealed. Two types of size distribution domains such as cluster-like (between 200 and 400 nm), which are the habitat of ''small'' hydroxyapatite nanocrystallites and scattered-like, which are the habitat of ''large'' hydroxyapatite nanocrystallites was probed by TEM and CSLM. The structural features of composites suggest that self-assembly processes might be involved. The composites contain nanosized hydroxyapatite with structural features close to those of biological apatites that make them attractive for bone

  4. Evidences of plasmonic effect in an organic-inorganic hybrid photovoltaic device using flower-like ZnO@Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Pan, Tong-Sheng; Sharma, Jadab; Chu, Chih-Chien; Tai, Yian

    2014-10-01

    Using flower-like ZnO@Au nanoparticles as external additives in an organic-inorganic hybrid solar cell device, we investigate the surface plasmon resonance (SPR) effect of gold nanoparticles. The active layer of the device consists of a usual polymeric blend of poly(3-hexylthiophene) and surface functionalized ZnO nanorods, which is conventionally known for its poor power conversion efficiency. We present the experimental evidences of improvement over UV-visible absorption properties and photocurrent generation due to the SPR effect. As a result, improvement is reported for short circuit current density and efficiency of the device on addition of flower-like ZnO@Au nanostructures.

  5. Organic/Inorganic Hybrid Nanostructures for Chemical Plasmonic Sensors

    NASA Astrophysics Data System (ADS)

    Chang, Sehoon

    2011-12-01

    The work presented in this dissertation suggests novel design of chemical plasmonic sensors which have been developed based on Localized Surface Plasmon Resonance (LSPR), and Surface-enhanced Raman scattering (SERS) phenomena. The goal of the study is to understand the SERS phenomena for 3D hybrid (organic/inorganic) templates and to design of the templates for trace-level detection of selected chemical analytes relevant to liquid explosives and hazardous chemicals. The key design criteria for the development of the SERS templates are utilizing selective polymeric nanocoatings within cylindrical nanopores for promoting selective adsorption of chemical analyte molecules, maximizing specific surface area, and optimizing concentration of hot spots with efficient light interaction inside nanochannels. The organic/inorganic hybrid templates are optimized through a comprehensive understanding of the LSPR properties of the gold nanoparticles, gold nanorods, interaction of light with highly porous alumina template, and the choice of physical and chemical attributes of the selective coating. Furthermore, novel method to assemble silver nanoparticles in 3D as the active SERS-active substrate has been demonstrated by uniform, in situ growth of silver nanoparticles from electroless deposited silver seeds excluding any adhesive polymer layer on template. This approach can be the optimal for SERS sensing applications because it is not necessary to separate the Raman bands of the polyelectrolyte binding layer from those of the desired analyte. The fabrication method is an efficient, simple and fast way to assemble nanoparticles into 3D nanostructures. Addressable Raman markers from silver nanowire crossbars with silver nanoparticles are also introduced and studied. Assembly of silver nanowire crossbar structure is achieved by simple, double-step capillary transfer lithography. The on/off SERS properties can be observed on silver nanowire crossbars with silver nanoparticles

  6. Gold nanoparticles-induced enhancement of the analytical response of an electrochemical biosensor based on an organic-inorganic hybrid composite material.

    PubMed

    Barbadillo, M; Casero, E; Petit-Domínguez, M D; Vázquez, L; Pariente, F; Lorenzo, E

    2009-12-15

    The design and characterization of a new organic-inorganic hybrid composite material for glucose electrochemical sensing are described. This material is based on the entrapment of both gold nanoparticles (AuNPs) and glucose oxidase, which was chosen as a model, into a sol-gel matrix. The addition of spectroscopic grade graphite to this system, which confers conductivity, leads to the development of a material particularly attractive for electrochemical biosensor fabrication. The characterization of the hybrid composite material was performed using atomic force microscopy and scanning electron microscopy techniques. This composite material was applied to the determination of glucose in presence of hydroxymethylferrocene as a redox mediator. The system exhibits a clear electrocatalytic activity towards glucose, allowing its determination at 250 mV vs Ag/AgCl. The performance of the resulting enzyme biosensor was evaluated in terms of sensitivity, detection limit, linear response range, stability and accuracy. Finally, the enhancement of the analytical response of the resulting biosensor induced by the presence of gold nanoparticles was evaluated by comparison with a similar organic-inorganic hybrid composite material without AuNPs.

  7. Electrodeposited Silver Nanoparticles Patterned Hexagonally for SERS

    SciTech Connect

    Gu, Geun Hoi; Lee, Sue Yeone; Suh, Jung Sang

    2010-08-06

    We have fabricated hexagonally patterned silver nanoparticles for surface-enhanced Raman scattering (SERS) by electrodepositing silver on the surface of an aluminum plate prepared by completely removing the oxide from anodic aluminum oxide (AAO) templates. Even after completely removing the oxide, well-ordered hexagonal patterns, similar to the shape of graphene, remained on the surface of the aluminum plate. The borders of the hexagonal pattern protruded up to form sorts of nano-mountains at both the sides and apexes of the hexagon, with the apexes protruding even more significantly than the sides. The aluminum plate prepared by completely removing the oxide has been used in the preparation of SERS substrates by sputter-coating of gold or silver on it. Instead of sputter-coating, here we have electro-deposited silver on the aluminum plate. When silver was electro-deposited on the plate, silver nanoparticles were made along the hexagonal margins.

  8. Comprehensive analysis of photonic effects on up-conversion of β-NaYF4:Er3+ nanoparticles in an organic-inorganic hybrid 1D photonic crystal

    NASA Astrophysics Data System (ADS)

    Hofmann, C. L. M.; Fischer, S.; Reitz, C.; Richards, B. S.; Goldschmidt, J. C.

    2016-04-01

    Upconversion (UC) presents a possibility to exploit sub-bandgap photons for current generation in solar cells by creating one high-energy photon out of at least two lower-energy photons. Photonic structures can enhance UC by two effects: a locally increased irradiance and a modified local density of photon states (LDOS). Bragg stacks are promising photonic structures for this application, because they are straightforward to optimize and overall absorption can be increased by adding more layers. In this work, we present a comprehensive simulation-based analysis of the photonic effects of a Bragg stack on UC luminescence. The investigated organic-inorganic hybrid Bragg stack consists of alternating layers of Poly(methylmethacrylate) (PMMA), containing purpose-built β-NaYF4:25% Er3+ core-shell nanoparticles and titanium dioxide (TiO2). From optical characterization of single thin layers, input parameters for simulations of the photonic effects are generated. The local irradiance enhancement and modulated LDOS are first simulated separately. Subsequently they are coupled in a rate equation model of the upconversion dynamics. Using the integrated model, UC luminescence is maximized by adapting the Bragg stack design. For a Bragg stack of only 5 bilayers, UC luminescence is enhanced by a factor of 3.8 at an incident irradiance of 2000 W/m2. Our results identify the Bragg stack as promising for enhancing UC, especially in the low-irradiance regime, relevant for the application in photovoltaics. Therefore, we experimentally realized optimized Bragg stack designs. The PMMA layers, containing UC nanoparticles, are produced via spin-coating from a toluene based solution. The TiO2 layers are produced by atomic layer deposition from molecular precursors. The reflectance measurements show that the realized Bragg stacks are in good agreement with predictions from simulation.

  9. Organic-inorganic hybrid supermicroporous iron(III) phosphonate nanoparticles as an efficient catalyst for the synthesis of biofuels.

    PubMed

    Pramanik, Malay; Bhaumik, Asim

    2013-06-24

    Here we report a novel family of crystalline, supermicroporous iron(III) phosphonate nanomaterials (HFeP-1-3, HFeP-1-2, and HFeP-1-4) with different Fe(III)-to-organophosphonate ligand mole ratios. The materials were synthesized by using a hydrothermal reaction between benzene-1,3,5-triphosphonic acid and iron(III) chloride under acidic conditions (pH ≈ 4.0). Powder X-ray diffraction, N2 sorption, transmission and scanning electron microscopy (TEM and SEM) image analysis, thermogravimetric and differential thermal analysis (TGA-DTA), and FTIR spectroscopic tools were used to characterize the materials. The triclinic crystal phase [P1(2) space group] of the hybrid iron phosphonate was established by a Rietveld refinement of the PXRD analysis of HFeP-1-3 by using the MAUD program. The unit cell parameters are a = 8.749(1), b = 8.578(1), c = 17.725(3) Å; α = 104.47(3), β = 97.64(1), γ = 113.56(3)°; and V = 1013.41 Å(3). With these crystal parameters, we proposed an 24-membered-ring open framework structure for HFeP-1. Compound HFeP-1-3, with an starting Fe/ligand molar ratio of 3.0, shows the highest Brunauer-Emmett-Telller (BET) surface area of 556 m(2) g(-1) and uniform supermicropores of approximately 1.1 nm. The acidic surface of the porous iron(III) phosphonate nanoparticles was used in a highly efficient and recyclable catalytic transesterification reaction for the synthesis of biofuels under mild reaction conditions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Sers-Based Aqueous Immunoassay Realized with Silica Nanoparticles

    NASA Astrophysics Data System (ADS)

    Song, C. Y.; Wang, Z. Y.; Yang, J.; Zhang, R. H.; Wu, H.; Cui, Y. P.

    A simple, sensitive SERS-based immunoassay realized in aqueous solution is demonstrated with a sandwich immune protocol. In such an immunoassay, antibodies-immobilized silica nanoparticles served as the immune substrate while 4MBA-labeled immuno-Au nanoparticles are used as the immune sensors. According to the TEM images, it is clear that the immune gold nanoparticles are embedded onto the surfaces of the silica nanoparticles specifically after the immunoreaction. As a result, the aggregations of gold nanoparticles have been formed with SERS-active "hot spots" on the dimers or multimers. The SERS results confirm that the method proposed in this paper is an effective way for SERS-based aqueous immunoassay and that the detection limit is as low as 0.1 ng/mL.

  11. SERS investigation of coatings on thermal modified titanium dioxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Amininejad, Sayed; Niessner, Reinhard; Baumann, Thomas

    2017-04-01

    Titanium dioxide nanoparticles (TiO2) are progressively manufactured and used in a wide variety of products such as sunscreens, papers, paints and toothpastes. The increase in the production and use of Titanium dioxide nanoparticles would escalate the risk for exposure of the natural environments to these compounds. There are several techniques for identifying and quantifying nanoparticles and Surface-Enhanced Raman Scattering (SERS) is an emerging technique which combines raman spectroscopy with nanotechnology. SERS can also be used to investigate the changes of natural coatings on nanoparticles as an important factor regarding their environmental fate and biological effects. In this work, TiO2 P25 nanoparticles are thermally modified at different temperatures to study the effects of thermal shock on the crystal structure, surface properties and subsequently the Surface-Enhanced Raman Scattering from 4-Mercaptobenzoic acid molecules coated on TiO2 nanoparticles has been observed. The results show that 4-Mercaptobenzoic acid molecules coated on nanoparticles exhibit different degree SERS enhancement on the surface of different nanoparticles modified at different temperatures by thermal modification method. This research work is expected to be important for improving SERS performance of TiO2 nanoparticles for characterization of natural coatings. Keywords: SERS, TiO2, 4-Mercaptobenzoic acid

  12. SERS enhancement dependence on the diameter of Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Yang, Yifei

    2017-06-01

    Series of Au colloidal solutions with different diameters were synthesized by the chemical reaction method. The influence of Au nanoparticles with different size on SERS of R6G was investigated. Experiments indicate that the enhancement factor grows in direct proportion to size of Au nanoparticles within limit.

  13. Synthesis, characterization and SERS activity of biosynthesized silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Bindhu, M. R.; Sathe, V.; Umadevi, M.

    2013-11-01

    Silver nanoparticles were rapidly synthesized using Moringa oleifera flower extract as the reducing agent shows surface plasmon resonance peak at 439 nm. The size and shape of the nanoparticles controlled by varying the concentration of M. oleifera flower extract in the reaction medium. The synthesized silver nanoparticles were well-dispersed spherical nanoparticles with the average size of 14 nm. The retinoic acid present in M. oleifera flower extract used as reducing agent and proteins was responsible for capping of the bioreduced silver nanoparticles. The obtained nanoparticle shows size-dependent SERS activity. The SERS spectrum indicates that the pyridine adsorbed on the silver surface in a stand-on orientation via its nitrogen lone pair electrons.

  14. Unique Gold Nanoparticle Aggregates as a Highly Active SERS Substrate

    SciTech Connect

    Schwartzberg, A M; Grant, C D; Wolcott, A; Talley, C E; Huser, T R; Bogomolni, R; Zhang, J Z

    2004-04-06

    A unique gold nanoparticle aggregate (GNA) system has been shown to be an excellent substrate for surface-enhanced Raman scattering (SERS) applications. Rhodamine 6G (R6G), a common molecule used for testing SERS activity on silver, but generally difficult to detect on gold substrates, has been found to readily bind to the GNA and exhibit strong SERS activity due to the unique surface chemistry afforded by sulfur species on the surface. This GNA system has yielded a large SERS enhancement of 10{sup 7}-10{sup 9} in bulk solution for R6G, on par with or greater than any previously reported gold SERS substrate. SERS activity has also been successfully demonstrated for several biological molecules including adenine, L-cysteine, L-lysine, and L-histidine for the first time on a gold SERS substrate, showing the potential of this GNA as a convenient and powerful SERS substrate for biomolecular detection. In addition, SERS spectrum of R6G on single aggregates has been measured. We have shown that the special surface properties of the GNA, in conjunction with strong near IR absorption, make it useful for SERS analysis of a wide variety of molecules.

  15. Application of SERS Nanoparticles for Intracellular pH Measurements

    SciTech Connect

    Laurence, T; Talley, C; Colvin, M; Huser, T

    2004-10-21

    We present an alternative approach to optical probes that will ultimately allow us to measure chemical concentrations in microenvironments within cells and tissues. This approach is based on monitoring the surface-enhanced Raman scattering (SERS) response of functionalized metal nanoparticles (50-100 nm in diameter). SERS allows for the sensitive detection of changes in the state of chemical groups attached to individual nanoparticles and small clusters. Here, we present the development of a nanoscale pH meter. The pH response of these nanoprobes is tested in a cell-free medium, measuring the pH of the solution immediately surrounding the nanoparticles. Heterogeneities in the SERS signal, which can result from the formation of small nanoparticle clusters, are characterized using SERS correlation spectroscopy and single particle/cluster SERS spectroscopy. The response of the nanoscale pH meters is tested under a wide range of conditions to approach the complex environment encountered inside living cells and to optimize probe performance.

  16. Design of Raman active nanoparticles for SERS-based detection

    NASA Astrophysics Data System (ADS)

    Garza, Javier T.; Cote, Gerard L.

    2016-03-01

    Timely detection of cardiac biomarkers is needed to diagnose acute myocardial infarction, implement the appropriate early treatment, and significantly reduce the chance of mortality. Ideally, for maximizing patient impact, a point of care device needs to be designed that is fast, sensitive, reliable, and small enough to be used in the ambulance and emergency department. Surface enhanced Raman spectroscopy (SERS) is a sensitive optical technique that can potentially be used to quantify the cardiac biomarkers of interest. In this work, silver nanoparticles were functionalized with a Raman reporter molecule and human cardiac Troponin I (cTnI) as an essential component of binding assays. Aggregated nanoparticles with the Raman reporter molecules were encapsulated in a silica shell to form SERS hotspots. Besides having a specific Raman spectra and binding affinity to cardiac Troponin I antibodies, the nanoparticles were designed to exhibit stability by using silica and polyethylene glycol (PEG) as part of the bioconjugation strategy. The specific narrow peaks from the Raman reporter molecule SERS signal allow for potential multiplexing capabilities as different Raman reporter molecules can be used in functionalized nanoparticles with different cardiac biomarkers. The SERS spectrum of the functionalized nanoparticles was measured to assess its potential to be used in an assay.

  17. Hybrid organic-inorganic nanoparticles: controlled incorporation of gold nanoparticles into virus-like particles and application in surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Niebert, Marcus; Riches, James; Howes, Mark; Ferguson, Charles; Parton, Robert G.; Middelberg, Anton P. J.; Rintoul, Llew; Fredericks, Peter M.

    2007-01-01

    A capsid is the protein coat surrounding a virus' genome that ensures its protection and transport. The capsid of murine polyomavirus (muPy) consists of one major (VP1) and two minor (VP2/3) proteins, from which just VP1 is sufficient to form the capsid when expressed recombinantly (1). From a material engineering point of view, viral capsids are of interest because they present a paradigm for complex self-assembly on the nanometer scale. Understanding and controlling these assembly dynamics will allow the construction of nanoscale structures using a self-assembly process. The first step in this direction was the discovery that capsids of several viruses can be reversibly disassembled into their building blocks and reassembled using the same building blocks by simply changing the buffer conditions (2, 3). Such capsids already find applications as targeted in vivo delivery vectors for genes, proteins or small molecular drugs (4, 5), as optical probes for biomedical imaging and sensing purposes with unprecedented resolution and sensitivity and can potentially be used as templates for nanoelectronics (6, 7). Here we show the controlled incorporation of inorganic gold nanoparticles into the capsid shell of muPy. This incorporation is mediated by covalent sulfide bonds between the capsid proteins cysteine residues and the molecular gold. The number of incorporated gold particles can be controlled during the assembly process and the capsids retain their ability to transduce cells. These particles provide new tools for tracking of viral particles in cells, and simultaneously allow the delivery of genes packages in the hollow capsid.

  18. Gold nanoparticles modified double-tapered fiber for SERS detection

    NASA Astrophysics Data System (ADS)

    Zhao, Chunqin; Chen, Na; liu, Shupeng; Chen, Zhenyi; Wang, Tingyun

    2017-06-01

    Double-tapered fiber probes modified with gold nanoparticles were fabricated for the surface-enhanced Raman scattering (SERS) sensing. Its performance was compared with the fiber SERS probes of flat end and of single-tapered structure. The remote detection performances of three fiber probe structures were compared by detecting rhodamine 6G (R6G) aqueous solutions with the different concentrations. The results of remote detection of R6G aqueous solution indicate that double-tapered fiber probe with the detection limit of 10-9 M is the most sensitive.

  19. Near-field and SERS enhancement from rough plasmonic nanoparticles

    NASA Astrophysics Data System (ADS)

    Trügler, Andreas; Tinguely, Jean-Claude; Jakopic, Georg; Hohenester, Ulrich; Krenn, Joachim R.; Hohenau, Andreas

    2014-04-01

    The lithographic fabrication of metal nanoparticles usually involves the thermal vacuum deposition of metals, which leads to polycrystallinity and surface roughness. In recent years, strong efforts have been made to clarify the role of such roughness in surface-enhanced Raman scattering (SERS). In this paper, we provide a systematic experimental and theoretical study of single lithographically fabricated nanoparticles to unravel the role of surface roughness and morphology on the optical far- and near-field properties. We find that the experimentally observed reduction of the SERS signal upon thermal annealing of particle arrays is caused by a complex interplay of changes in the dielectric response of gold, the resonance wavelength, and the reduced nanoscopic roughness.

  20. High proton-conducting organic/inorganic nanocomposite films based on sulfonated polystyrene-block-poly(ethyl-ran-propylene)-block-polystyrene and silica nanoparticles.

    PubMed

    Jang, Suk-Yong; Han, Sien-Ho

    2013-12-01

    Sulfonated polystyrene-block-poly(ethyl-ran-propylene)-block-polystyrene (S-polySEPS) was prepared by sulfonation at the phenyl groups of the polystyrene-block-poly(ethyl-ran-propylene)-block-polystyrene (polySEPS) containing 65% styrene groups for proton exchange membrane. High proton-conducting S-polySEPS/silica nanocomposite films were produced by direct-mixing of nanosilica particles with the S-polySEPS copolymer. The TEM image of the S-polySEPS/silica nanocomposite films showed that the silica particles were very-well dispersed within the S-polySEPS matrix. Also, the XRD patterns showed the presence of the nano-scaled silica particles. Moreover, the nano-scaled silica particles played an important role in the prepared organic/inorganic nanocomposite properties such as proton conductivity, thermal stability, water content and ion exchange capacity (IEC). The S-polySEPS/silica 1 wt% (1.41 x 10(-1) S/cm) and 2 wt% (9.9 x 10(-2) S/cm) nanocomposite films had higher proton conductivity than Nafion 117 (9.8 x 10(-2) S/cm) at the temperature of 90 degrees C. The FT-IR analysis was used to verify the sulfonation of the S-polySEPS copolymer. The TGA analysis was carried out to investigate the thermal stability of the S-polySEPS/silica nanocomposite films.

  1. SDS bubbles functionalized with Gold nanoparticles and SERS applications

    NASA Astrophysics Data System (ADS)

    Navarro-Badilla, A.; Hurtado, R. Britto; Cortez-Valadez, M.; Perez-Rodriguez, A.; Flores-Acosta, M.; Maldonado-Arce, A.

    2017-03-01

    We present a method of incorporation of gold nanoparticles in SDS (sodium dodecyl sulfate) bubbles with a low polydispersity index (monodispersed nanoparticles). Both the bubbles and nanoparticles maintained their structural and morphologic properties after functionalization. The bubbles present a radio of 0.38 mm with a standard deviation of±0.018 mm. The gold nanoparticles were obtained with sucrose as the catalytic agent and ascorbic acid as the reducing agent. The nanoparticles display several geometric morphologies as well as sizes inferior to 50 nm, as observed in the images obtained with Transmission Electron Microscopy (TEM). The optical properties were studied by optical absorption spectroscopy. The absorption band linked to the surface plasmon resonance (SPR) is located at 550 nm before and after the functionalization of the bubbles. Moreover, microscopic bubbles with a diameter smaller than 1 μm with the ability to stabilize nanoparticles in their surface were found in isolated regions of the sample. Additionally, the Surface Enhancement Raman Spectroscopy (SERS) properties of the colloid were analyzed with common drugs.

  2. SERS of semiconducting nanoparticles (TIO{sub 2} hybrid composites).

    SciTech Connect

    Rajh, T.; Musumeci, A.; Gosztola, D.; Schiller, T.; Dimitrijevic, N. M.; Mujica, V.; Martin, D.; Center for Nanoscale Materials

    2009-05-06

    Raman scattering of molecules adsorbed on the surface of TiO{sub 2} nanoparticles was investigated. We find strong enhancement of Raman scattering in hybrid composites that exhibit charge transfer absorption with TiO{sub 2} nanoparticles. An enhancement factor up to {approx}10{sup 3} was observed in the solutions containing TiO{sub 2} nanoparticles and biomolecules, including the important class of neurotransmitters such as dopamine and dopac (3,4-dihydroxy-phenylacetic acid). Only selected vibrations are enhanced, indicating molecular specificity due to distinct binding and orientation of the biomolecules coupled to the TiO{sub 2} surface. All enhanced modes are associated with the asymmetric vibrations of attached molecules that lower the symmetry of the charge transfer complex. The intensity and the energy of selected vibrations are dependent on the size and shape of nanoparticle support. Moreover, we show that localization of the charge in quantized nanoparticles (2 nm), demonstrated as the blue shift of particle absorption, diminishes SERS enhancement. Importantly, the smallest concentration of adsorbed molecules shows the largest Raman enhancements suggesting the possibility for high sensitivity of this system in the detection of biomolecules that form a charge transfer complex with metal oxide nanoparticles. The wavelength-dependent properties of a hybrid composite suggest a Raman resonant state. Adsorbed molecules that do not show a charge transfer complex show weak enhancements probably due to the dielectric cavity effect.

  3. Graphite oxide-coated Au nanoparticles for improved SERS sensing

    NASA Astrophysics Data System (ADS)

    Liu, Bingfei; Wang, Qi; Tian, Tian; Mao, Guoming; Liu, Hao; Ren, Xiao Min

    2016-11-01

    Surface-enhanced Raman scattering (SERS) is an effective spectral analysis technique as its advantage of molecular fingerprint, ultra-sensitivity and non-contact. It is the most popular and easiest method to create SERS metal nanoparticles (NPs) combining magnetron sputtering deposition of noble metal with rapid annealing. In this study, we have demonstrated an approach to improve the SERS effect by using graphene oxide (GO) Au NPs composite structure. Here, we obtain the Au NPs coated SOI substrate prepared by magnetron sputtering 4 nm Au film and followed by rapid annealing treatment. The experimental results indicate that the SERS intensity is maximum of the Au NPs coated SOI substrate with the average particle diameter of 20 nm when the rapid annealing time is 30s and temperature is 500 degrees. Then, graphene oxide solution is spin coated on the Au NPs to form the GO-Au NPs composite structure. The morphology of GO-Au NPs have been characterized by scanning electron microscope (SEM). Rhodamine 6G (R6G) is used as the probe molecule to detect the SERS intensity. The GO-Au NPs has an excellent SERS effect which can detect R6G as low as 10-9M. Besides, compared to the Au NPs without GO the GO-Au NPs has two times Raman intensity enhancement of bands at 774 cm-1 because of the GO improving the SERS properties through strong ability of adsorption the probe molecule and chemical enhancement effect. Therefore, the GO-Au NPs composite structure shows a promising future to detect low concentration material.

  4. SERS-active nanoparticle aggregate technology for tags and seals

    SciTech Connect

    Brown, Leif O; Montoya, Velma M; Havrilla, George J; Doorn, Stephen K

    2010-06-03

    In this paper, we describe our efforts to create a modern tagging and sealing technology for international safeguards application. Our passive tagging methods are based on SANAs (SERS-Active Nanoparticle Aggregates; SERS: Surface Enhanced Raman Scattering). These SANAs offer robust spectral barcoding capability in an inexpensive tag/seal, with the possibility of rapid in-field verification that requires no human input. At INMM 2009, we introduced SANAs, and showed approaches to integrating our technology with tags under development at Sandia National Laboratories (SNL). Here, we will focus on recent LANL development work, as well as adding additional dimensionality to the barcoding technique. The field of international safeguards employs a broad array of tags, seals, and tamper-indicating devices to assist with identification, tracking, and verification of components and materials. These devices each have unique strengths suited to specific applications, and span a range of technologies from passive metal cup seals and adhesive seals to active, remotely monitored fiber optic seals. Regardless of the technology employed, essential characteristics center around security, environmental and temporal stability, ease of use, and the ability to provide confidence to all parties. Here, we present a new inexpensive tagging technology that will deliver these attributes, while forming the basis of either a new seal, or as a secure layer added to many existing devices. Our approach uses the Surface Enhanced Raman Scattering (SERS) response from SANAs (SERS-Active Nanoparticle Aggregates, Figure 1) to provide a unique identifier or signature for tagging applications. SANAs are formed from gold or silver nanoparticles in the 40-80 nm size range. A chemical dye is installed on the nanoparticle surface, and the nanoparticles are then aggregated into ensembles of {approx}100 to 500 nm diameter, prior to being coated with silica. The silica shell protects the finished SANA from

  5. Charge carrier mobility in an organic-inorganic hybrid nanocomposite

    NASA Astrophysics Data System (ADS)

    Choudhury, Kaushik Roy; Winiarz, Jeffrey G.; Samoc, Marek; Prasad, Paras N.

    2003-01-01

    Organic-inorganic hybrid materials are media for electronic and optoelectronic applications. We present a study of the electronic transport in such a model nanoparticle-sensitized hybrid organic-inorganic photorefractive host system, consisting of poly(N-vinylcarbazole) doped with quantum dots of cadmium sulfide, using standard time-of-flight techniques. The photocurrent transients exhibit features typical of dispersive transport in an amorphous semiconductor. The hole mobility depends strongly on the electric field and temperature indicating Poole-Frenkel-like activated hopping transport; a thickness dependence of the mobility is observed. The presence of nanoparticles does not lead to increased trapping of holes. Conversely, a surprising result is observed: the mobility actually increases with the increase of nanoparticle concentration even though it is well below the percolation limit.

  6. Raman gas sensing of modified Ag nanoparticle SERS

    NASA Astrophysics Data System (ADS)

    Myoung, NoSoung; Yoo, Hyung Keun; Hwang, In-Wook

    2014-03-01

    Recent progress in modified Surface Enhanced Raman Scattering (SERS) using Ag nanoparticles makes them promising optical technique for direct gas sensing of interest. However, SERS has been shown to provide sub ppb level detection of the compounds in the vapor phase. The major problem with the sensitivity scaling-up was in the development of fabrication technology for stability and reproducibility of SERS substrates. We report an optimization of 1-propanethiol coated multiple Ag nanoparticle layers on SiO2 substrate as well as new records of real-time, simultaneous vapor phase detection of toluene and 1-2 dichlorobenzene by the radiation of fiber optic coupled 785 nm diode laser and spectrograph. Multiple depositions of Ag NPs were loaded on SiO2 and soaked in 1-propanethiol solution for 24 hours to modify the surface into hydrophobic due to the characteristics of vapor phase of our interests. Raman bands at 1003 cm-1 and 1130 cm-1 for toluene and 12DCB, respectively were compared to 1089 cm-1 and each gas concentration in 1000 mL flask were calculated as a function of each vapor phase ratio. The saturation of toluene and 12DCB were limited only by 800 ppm and the detectable range was 0.6-800 ppm.

  7. Au-ZnO hybrid nanoparticles exhibiting strong charge-transfer-induced SERS for recyclable SERS-active substrates

    NASA Astrophysics Data System (ADS)

    Liu, Liping; Yang, Haitao; Ren, Xiao; Tang, Jin; Li, Yongfeng; Zhang, Xiangqun; Cheng, Zhaohua

    2015-03-01

    Flower-shaped Au-ZnO hybrid nanoparticles have been prepared via seeding growth and subsequent wet-chemical etching of Au-ZnO core-shell nanoparticles. The etched Au-ZnO hybrid nanoparticles have shown a stronger surface-enhanced Raman scattering (SERS) signal of the nontotally symmetric (b2) vibrational modes of PATP molecules than Au nanoparticles alone, which is attributed to the chemical enhancement effect of the ZnO layer which is greatly excited by the localized surface plasmon resonance (LSPR) of Au cores. Further, the mechanism of the LSPR-enhanced charge transfer (CT) effect has been proved by the SERS spectra of PATP molecules excited using different laser sources from 325 to 785 nm. Moreover, the photocatalytic experimental results indicated that Au-ZnO hybrid nanoparticles are promising as biologically compatible and recyclable SERS-active platforms for different molecular species.Flower-shaped Au-ZnO hybrid nanoparticles have been prepared via seeding growth and subsequent wet-chemical etching of Au-ZnO core-shell nanoparticles. The etched Au-ZnO hybrid nanoparticles have shown a stronger surface-enhanced Raman scattering (SERS) signal of the nontotally symmetric (b2) vibrational modes of PATP molecules than Au nanoparticles alone, which is attributed to the chemical enhancement effect of the ZnO layer which is greatly excited by the localized surface plasmon resonance (LSPR) of Au cores. Further, the mechanism of the LSPR-enhanced charge transfer (CT) effect has been proved by the SERS spectra of PATP molecules excited using different laser sources from 325 to 785 nm. Moreover, the photocatalytic experimental results indicated that Au-ZnO hybrid nanoparticles are promising as biologically compatible and recyclable SERS-active platforms for different molecular species. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00491h

  8. Gold nanoparticles paper as a SERS bio-diagnostic platform.

    PubMed

    Ngo, Ying Hui; Then, Whui Lyn; Shen, Wei; Garnier, Gil

    2013-11-01

    Bioactive papers are usually challenged by four major limitations: sensitivity, selectivity, simplicity and strength (4S). Gold nanoparticles (AuNPs) treated paper has previously been demonstrated as a Surface Enhanced Raman Scattering (SERS) active substrate, capable of addressing the 4S issues. In this study, AuNPs on paper substrate were functionalized by a series of biomolecules to develop a generic SERS platform for antibody-antigen detection. The functionalization steps were performed by taking advantage of the high affinity association between Streptomyces avidinii-derived protein, streptavidin, and biotin. Streptavidin was firstly bound onto the AuNPs treated paper using biotinylated-thiol. Subsequently, desired biotinylated-antibody was bound onto the streptavidin. SERS spectra of each functionalization step were obtained to ensure specific adsorption of the bio-molecules. The binding interaction of the antibody with its specific antigen was detected using SERS. Shifts of Raman band associated with α-helix and β-sheet structures indicated structural modification of the antibody upon interaction with its antigen. Predominant tryptophan and tyrosine residue bands were also detected, confirming the presence of antigen. Reproducible spectral features were quantified as AuNP papers were subjected to different concentrations of antigen; the spectra intensity increased as a function of the antigen concentration. The retention of AuNPs on paper remained constant after all the consecutive washing and functionalization steps. The feasibility of AuNPs paper as a low-cost and generic SERS platform for bio-diagnostic applications was demonstrated. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  9. Robust platforms for creating organic-inorganic nanocomposite microspheres: decorating polymer microspheres containing mussel-inspired adhesion layers with inorganic nanoparticles.

    PubMed

    Satoh, H; Saito, Y; Yabu, H

    2014-12-07

    We describe a method for creating robust and stable core-shell polymer microspheres decorated with inorganic (IO) nanoparticles (NPs) by a self-organization process and heterocoagulation using a mussel-inspired polymer adhesive layer between the IO NPs and the microspheres.

  10. Self-assembled hierarchically structured organic-inorganic composite systems.

    PubMed

    Tritschler, Ulrich; Cölfen, Helmut

    2016-05-13

    Designing bio-inspired, multifunctional organic-inorganic composite materials is one of the most popular current research objectives. Due to the high complexity of biocomposite structures found in nacre and bone, for example, a one-pot scalable and versatile synthesis approach addressing structural key features of biominerals and affording bio-inspired, multifunctional organic-inorganic composites with advanced physical properties is highly challenging. This article reviews recent progress in synthesizing organic-inorganic composite materials via various self-assembly techniques and in this context highlights a recently developed bio-inspired synthesis concept for the fabrication of hierarchically structured, organic-inorganic composite materials. This one-step self-organization concept based on simultaneous liquid crystal formation of anisotropic inorganic nanoparticles and a functional liquid crystalline polymer turned out to be simple, fast, scalable and versatile, leading to various (multi-)functional composite materials, which exhibit hierarchical structuring over several length scales. Consequently, this synthesis approach is relevant for further progress and scientific breakthrough in the research field of bio-inspired and biomimetic materials.

  11. Surface Partitioning in Organic-Inorganic Mixtures Contributes to the Size-Dependence of the Phase-State of Atmospheric Nanoparticles.

    PubMed

    Werner, Josephina; Dalirian, Maryam; Walz, Marie-Madeleine; Ekholm, Victor; Wideqvist, Ulla; Lowe, Samuel J; Öhrwall, Gunnar; Persson, Ingmar; Riipinen, Ilona; Björneholm, Olle

    2016-07-19

    Atmospheric particulate matter is one of the main factors governing the Earth's radiative budget, but its exact effects on the global climate are still uncertain. Knowledge on the molecular-scale surface phenomena as well as interactions between atmospheric organic and inorganic compounds is necessary for understanding the role of airborne nanoparticles in the Earth system. In this work, surface composition of aqueous model systems containing succinic acid and sodium chloride or ammonium sulfate is determined using a novel approach combining X-ray photoelectron spectroscopy, surface tension measurements and thermodynamic modeling. It is shown that succinic acid molecules are accumulated in the surface, yielding a 10-fold surface concentration as compared with the bulk for saturated succinic acid solutions. Inorganic salts further enhance this enrichment due to competition for hydration in the bulk. The surface compositions for various mixtures are parametrized to yield generalizable results and used to explain changes in surface tension. The enhanced surface partitioning implies an increased maximum solubility of organic compounds in atmospheric nanoparticles. The results can explain observations of size-dependent phase-state of atmospheric nanoparticles, suggesting that these particles can display drastically different behavior than predicted by bulk properties only.

  12. Systematic investigation of the SERS efficiency and SERS hotspots in gas-phase deposited Ag nanoparticle assemblies.

    PubMed

    He, L B; Wang, Y L; Xie, X; Han, M; Song, F Q; Wang, B J; Chen, W L; Xu, H X; Sun, L T

    2017-02-15

    Gas-phase deposited Ag nanoparticle assemblies are one of the most commonly used plasmonic substrates benefiting from their remarkable advantages such as clean particle surface, tunable particle density, available inter-particle gaps, low-cost and scalable fabrication, and excellent industry compatibility. However, their performance efficiencies are difficult to optimize due to the lack of knowledge of the hotspots inside their structures. We here report a design of delicate rainbow-like Ag nanoparticle assemblies, based on which the hotspots can be revealed through a combinatorial approach. The findings show that the hotspots in gas-phase deposited Ag nanoparticle assemblies are uniquely entangled by the excitation energy and specific inter-particle gaps, differing from the matching conditions in periodic arrays. For Ag nanoparticle assemblies deposited on Formvar-filmed substrates, the mean particle size is maintained around 10 nm, while the particle density can be widely tuned. The one possessing the highest SERS efficiency (under 473 nm excitation) have a particle number density of around 7100 μm(-2). Gaps with an inter-particle spacing of around 3 nm are found to serve as SERS hotspots, and these hotspots contribute to 68% of the overall SERS intensity. For Ag nanoparticle assemblies fabricated on carbon-filmed substrates, the mean particle size can be feasibly tuned. The one possessing the highest SERS efficiency under 473 nm excitation has a particle number density of around 460 μm(-2) and a mean particle size of around 42.1 nm. The construction of Ag-analyte-Ag sandwich-like nanoparticle assemblies by a two-step-deposition method slightly improves the SERS efficiency when the particle number density is low, but suppresses the SERS efficiency when the particle number density is high.

  13. Natural hybrid organic-inorganic photovoltaic devices

    NASA Astrophysics Data System (ADS)

    De Padova, Paola; Lucci, Massimiliano; Olivieri, Bruno; Quaresima, Claudio; Priori, Sandro; Francini, Roberto; Grilli, Antonio; Hricovini, Karol; Davoli, Ivan

    2009-06-01

    Natural hybrid organic-inorganic photovoltaic devices based on TiO 2 have been realized. Chlorophyll A (from anacystis nidulans algae), chlorophyll B (from spinach), carmic acid (from insect Coccus cacti L.), synthetic trans- β-carotene, natural fresh picked Morus nigra, and their mixtures have been used as an organic photo active layer to fabricate photovoltaic prototypes. In order to reduce the charge's interfacial recombination, different thicknesses (5-45 nm) of Si layers, subsequently oxidized in air, were inserted between the TiO 2 and chlorophyll B. Scanning electron microscopy of TiO 2 and Si/TiO 2 systems shows the coexistence at least of four classes of nanoparticles of 60, 100, 150 and 250 nm in size. Auger electron spectroscopy of the Si L 2,3V V transition demonstrates the presence of silica and SiO x suboxides. Photocurrent measurements versus radiation wavelength in the range 300-800 nm exhibit different peaks according to the absorption spectra of the organic molecules. All realized photovoltaic devices are suitable for solar light electric energy conversion. Those made of a blend of all organic molecules achieved higher current and voltage output. The Si/TiO 2-based devices containing chlorophyll B exhibited an enhanced photocurrent response with respect to those with TiO 2 only.

  14. Orientation of glycine on silver nanoparticles: SERS studies

    NASA Astrophysics Data System (ADS)

    Parameswari, A.; Benial, A. Milton Franklin

    2016-05-01

    Surface enhanced Raman scattering (SERS) studies of glycine (Gly) adsorbed on silver nanoparticles (AgNPs) was investigated by experimental and density functional theory approach. The AgNPs were prepared and characterized. The molecular structure of the Gly and Gly adsorbed on silver cluster were optimized by the DFT/B3PW91 method with LanL2DZ basis set. The calculated and observed vibrational frequencies were assigned on the basis of potential energy distribution calculation. The perpendicular orientation of Gly on the silver surface was predicted from the enhanced Raman signal correspond to the C=O and C-H stretching vibrational modes. The frontier molecular orbitals analysis and molecular electrostatic potential calculation were carried out. The reduced band gap value was obtained for Gly adsorbed on silver nanoparticles, which paves the way for designing the bio molecular devices. The first order hyperpolarizability value for Ag-Gly is 461 times greater than the urea. Thus, Ag-Gly is a promising candidate for NLO materials.

  15. Chemically attached gold nanoparticle-carbon nanotube hybrids for highly sensitive SERS substrate

    NASA Astrophysics Data System (ADS)

    Beqa, Lule; Singh, Anant Kumar; Fan, Zheng; Senapati, Dulal; Ray, Paresh Chandra

    2011-08-01

    Surface-enhanced Raman spectroscopy (SERS) has been shown as one of the most powerful analytical tool with high sensitivity. In this manuscript, we report the chemical design of SERS substrate, based on gold nanoparticles of different shapes-decorated with carbon nanotube with an enhancement factor of 7.5 × 1010. Shape dependent result shows that popcorn shape gold nanoparticle decorated SWCNT is the best choice for SERS substrate due to the existence of 'lightning rod effect' through several sharp edges or corners. Our results provide a good approach to develop highly sensitive SERS substrates and can help to improve the fundamental understanding of SERS phenomena.

  16. Hybrid organic/inorganic reverse osmosis (RO) membrane for bactericidal anti-fouling. 1. Preparation and characterization of TiO2 nanoparticle self-assembled aromatic polyamide thin-film-composite (TFC) membrane.

    PubMed

    Kwak, S Y; Kim, S H; Kim, S S

    2001-06-01

    Hybrid organic/inorganic reverse osmosis (RO) membranes composed of aromatic polyamide thin films underneath titanium dioxide (TiO2) nanosized particles have been fabricated by a self-assembly process, aiming at breakthrough of biofouling problems. First, positively charged particles of the colloidal TiO2 were synthesized by a sol-gel process, and the diameter of the resulting particles in acidic aqueous solution was estimated to be approximately 2 nm by analyzing the UV-visible absorption characteristics with a quantum mechanical model developed by Brus. Transmission electron microscopy (TEM) further confirmed the formation of the quantum-sized TiO2 particles (approximately 10 nm or less). The TiO2 particles appeared to exist in the crystallographic form of anatase as observed with the X-ray diffraction (XRD) pattern in comparison with those of commercial 100% rutile and commercial 70:30% anatase-to-rutile mixture. The hybrid thin-film-composite (TFC) aromatic polyamide membranes were prepared by self-assembly of the TiO2 nanoparticles on the polymer chains with COOH groups along the surface. They showed improved RO performance in which the water flux even increased, though slightly. Field-emission scanning electron microscopy (FESEM) exhibited the TiO2 nanoparticles well adsorbed onto the surface. X-ray photoelectron spectroscopy (XPS) demonstrated quantitatively that a considerable amount of the adsorbed particles were tightly self-assembled at the expense of the initial loss of those that were loosely bound, and became stabilized even after exposure to the various washing and harsh RO operating conditions. The antibacterial fouling potential of the TiO2 hybrid membrane was examined and verified by measuring the viable numbers and determining the survival ratios of the Escherichia coli (E. coli) as a model bacterium, both with and without UV light illumination. The photocatalytic bactericidal efficiency was remarkably higher for the TiO2 hybrid membrane under UV

  17. Rough surface Au@Ag core-shell nanoparticles to fabricating high sensitivity SERS immunochromatographic sensors.

    PubMed

    Fu, Qiangqiang; Liu, Hongwu Liu; Wu, Ze; Liu, An; Yao, Cuize; Li, Xiuqing; Xiao, Wei; Yu, Shiting; Luo, Zhi; Tang, Yong

    2015-11-14

    Immunochromatographic sensors (ICSs) are inexpensive, simple, portable, and robust, thus making ICSs commonplace in clinical diagnoses, food testing, and environmental monitoring. However, commonly used gold nanoparticles (AuNPs) ICSs have low sensitivity. Therefore, we developed highly sensitive surface enhanced Raman scattering (SERS) ICSs. To enhance the sensitivity of SERS ICSs, rough surface core-shell Au@Ag nanoparticles (RSAu@AgNPs) were prepared by coating silver on the surface of gold nanoflowers (AuNFs). Then these nanoparticles were used as SERS substrate in the SERS ICSs, after which the SERS ICSs were implemented to detect haemoglobin and heavy metal cadmium ion (Cd(2+)). The limit of detection (LOD) of the SERS ICSs for detecting haemoglobin was 8 ng/mL, and the linear range of the SERS ICSs was from 31.3 to 2000 ng/mL. The LOD of the SERS ICSs for detecting Cd(2+) was 0.05 ng/mL and the linear analysis range was from 0.05 to 25 ng/mL. The cross reactivity of the SERS ICSs was studied and results showed that the SERS ICSs exhibited highly specific for detection of haemoglobin and Cd(2+), respectively. The SERS ICSs were then used to detect haemoglobin (spiked in serum and in stool) and Cd(2+) (spiked in tap water, river water, and soil leaching water), and the results showed high recovery. These characteristics indicated that SERS ICSs were ideal tools for clinical diagnosis and environmental pollution monitoring.

  18. SERS of Individual Nanoparticles on a Mirror: Size Does Matter, but so Does Shape

    PubMed Central

    2016-01-01

    Coupling noble metal nanoparticles by a 1 nm gap to an underlying gold mirror confines light to extremely small volumes, useful for sensing on the nanoscale. Individually measuring 10 000 of such gold nanoparticles of increasing size dramatically shows the different scaling of their optical scattering (far-field) and surface-enhanced Raman emission (SERS, near-field). Linear red-shifts of the coupled plasmon modes are seen with increasing size, matching theory. The total SERS from the few hundred molecules under each nanoparticle dramatically increases with increasing size. This scaling shows that maximum SERS emission is always produced from the largest nanoparticles, irrespective of tuning to any plasmonic resonances. Changes of particle facet with nanoparticle size result in vastly weaker scaling of the near-field SERS, without much modifying the far-field, and allows simple approaches for optimizing practical sensing. PMID:27223478

  19. Microfluidic setup for on-line SERS monitoring using laser induced nanoparticle spots as SERS active substrate

    PubMed Central

    Buja, Oana-M; Gordan, Ovidiu D; Morschhauser, Andreas; Nestler, Jörg; Zahn, Dietrich R T

    2017-01-01

    A microfluidic setup which enables on-line monitoring of residues of malachite green (MG) using surface-enhanced Raman scattering (SERS) is reported. The SERS active substrate was prepared via laser induced synthesis of silver or gold nanoparticles spot on the bottom of a 200 μm inner dimension glass capillary, by focusing the laser beam during a continuous flow of a mixture of silver nitrate or gold chloride and sodium citrate. The described microfluidic setup enables within a few minutes the monitoring of several processes: the synthesis of the SERS active spot, MG adsorption to the metal surface, detection of the analyte when saturation of the SERS signal is reached, and finally, the desorption of MG from the spot. Moreover, after MG complete desorption, the regeneration of the SERS active spot was achieved. The detection of MG was possible down to 10−7 M concentration with a good reproducibility when using silver or gold spots as SERS substrate. PMID:28243562

  20. Pollutant capturing SERS substrate: porous boron nitride microfibers with uniform silver nanoparticle decoration.

    PubMed

    Dai, Pengcheng; Xue, Yanming; Wang, Xuebin; Weng, Qunhong; Zhang, Chao; Jiang, Xiangfen; Tang, Daiming; Wang, Xi; Kawamoto, Naoyuki; Ide, Yusuke; Mitome, Masanori; Golberg, Dmitri; Bando, Yoshio

    2015-12-07

    How to concentrate target molecules on the surface of a SERS substrate is a key problem in the practical application of SERS. Herein, we designed for the first time a pollutant capturing surface enhanced Raman spectroscopy (SERS) substrate, namely porous BN microfibers uniformly decorated with Ag nanoparticles, in which the BN microfibers adsorb pollutants, while the Ag nanoparticles provide SERS activity. This SERS substrate captures pollutants from an aqueous solution completely and accumulates them all on its surface without introducing noise signals. The pores of BN protect the silver particles from aggregation which makes BN/Ag a stable and recyclable SERS substrate. What's more, while the dyes are thoroughly concentrated from a diluted solution, the SERS detection limit is easily enhanced, from 10(-6) M to 10(-9) M.

  1. Pollutant capturing SERS substrate: porous boron nitride microfibers with uniform silver nanoparticle decoration

    NASA Astrophysics Data System (ADS)

    Dai, Pengcheng; Xue, Yanming; Wang, Xuebin; Weng, Qunhong; Zhang, Chao; Jiang, Xiangfen; Tang, Daiming; Wang, Xi; Kawamoto, Naoyuki; Ide, Yusuke; Mitome, Masanori; Golberg, Dmitri; Bando, Yoshio

    2015-11-01

    How to concentrate target molecules on the surface of a SERS substrate is a key problem in the practical application of SERS. Herein, we designed for the first time a pollutant capturing surface enhanced Raman spectroscopy (SERS) substrate, namely porous BN microfibers uniformly decorated with Ag nanoparticles, in which the BN microfibers adsorb pollutants, while the Ag nanoparticles provide SERS activity. This SERS substrate captures pollutants from an aqueous solution completely and accumulates them all on its surface without introducing noise signals. The pores of BN protect the silver particles from aggregation which makes BN/Ag a stable and recyclable SERS substrate. What's more, while the dyes are thoroughly concentrated from a diluted solution, the SERS detection limit is easily enhanced, from 10-6 M to 10-9 M.How to concentrate target molecules on the surface of a SERS substrate is a key problem in the practical application of SERS. Herein, we designed for the first time a pollutant capturing surface enhanced Raman spectroscopy (SERS) substrate, namely porous BN microfibers uniformly decorated with Ag nanoparticles, in which the BN microfibers adsorb pollutants, while the Ag nanoparticles provide SERS activity. This SERS substrate captures pollutants from an aqueous solution completely and accumulates them all on its surface without introducing noise signals. The pores of BN protect the silver particles from aggregation which makes BN/Ag a stable and recyclable SERS substrate. What's more, while the dyes are thoroughly concentrated from a diluted solution, the SERS detection limit is easily enhanced, from 10-6 M to 10-9 M. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05625j

  2. Organic-Inorganic Composites Toward Biomaterial Application.

    PubMed

    Miyazaki, Toshiki; Sugawara-Narutaki, Ayae; Ohtsuki, Chikara

    2015-01-01

    Bioactive ceramics are known to exhibit specific biological affinities and are able to show direct integration with surrounding bone when implanted in bony defects. However, their inadequate mechanical properties, such as low fracture toughness and high Young's modulus in comparison to natural bone, limit their clinical application. Bone is a kind of organic-inorganic composite where apatite nanocrystals are precipitated onto collagen fibre networks. Thus, one way to address these problems is to mimic the natural composition of bone by using bioactive ceramics via material designs based on organic-inorganic composites. In this chapter, the current research on the development of the various organic-inorganic composites designed for biomaterial applications has been reviewed. Various compounds such as calcium phosphate, calcium sulphate and calcium carbonate can be used for the inorganic phases to design composites with the desired mechanical and biological properties of bone. Not only classical mechanical mixing but also coating of the inorganic phase in aqueous conditions is available for the fabrication of such composites. Organic modifications using various polymers enable the control of the crystalline structure of the calcium carbonate in the composites. These approaches on the fabrication of organic-inorganic composites provide important options for biomedical materials with novel functions. © 2015 S. Karger AG, Basel.

  3. Single-molecule and single-nanoparticle SERS: from fundamental mechanisms to biomedical applications.

    PubMed

    Qian, X-M; Nie, S M

    2008-05-01

    This tutorial review discusses a new class of colloidal metal nanoparticles that is able to enhance the efficiencies of surface-enhanced Raman scattering (SERS) by as much as 10(14)-10(15) fold. This enormous enhancement allows spectroscopic detection and identification of single molecules located on the nanoparticle surface or at the junction of two particles under ambient conditions. Considerable progress has been made in understanding the enhancement mechanisms, including definitive evidence for the single-molecule origin of fluctuating SERS signals. For applications, SERS nanoparticle tags have been developed based on the use of embedded reporter molecules and a silica or polymer encapsulation layer. The SERS nanoparticle tags are capable of providing detailed spectroscopic information and are much brighter than semiconductor quantum dots in the near-infrared spectral window. These properties have raised new opportunities for multiplexed molecular diagnosis and in vivo Raman spectroscopy and imaging.

  4. Alkylamine capped metal nanoparticle "inks" for printable SERS substrates, electronics and broadband photodetectors.

    PubMed

    Polavarapu, Lakshminarayana; Manga, Kiran Kumar; Yu, Kuai; Ang, Priscilla Kailian; Cao, Hanh Duyen; Balapanuru, Janardhan; Loh, Kian Ping; Xu, Qing-Hua

    2011-05-01

    We report a facile and general method for the preparation of alkylamine capped metal (Au and Ag) nanoparticle "ink" with high solubility. Using these metal nanoparticle "inks", we have demonstrated their applications for large scale fabrication of highly efficient surface enhanced Raman scattering (SERS) substrates by a facile solution processing method. These SERS substrates can detect analytes down to a few nM. The flexible plastic SERS substrates have also been demonstrated. The annealing temperature dependent conductivity of the nanoparticle films indicated a transition temperature above which high conductivity was achieved. The transition temperature could be tailored to the plastic compatible temperatures by using proper alkylamine as the capping agent. The ultrafast electron relaxation studies of the nanoparticle films demonstrated that faster electron relaxation was observed at higher annealing temperatures due to stronger electronic coupling between the nanoparticles. The applications of these highly concentrated alkylamine capped metal nanoparticle inks for the printable electronics were demonstrated by printing the oleylamine capped gold nanoparticles ink as source and drain for the graphene field effect transistor. Furthermore, the broadband photoresponse properties of the Au and Ag nanoparticle films have been demonstrated by using visible and near-infrared lasers. These investigations demonstrate that these nanoparticle "inks" are promising for applications in printable SERS substrates, electronics, and broadband photoresponse devices.

  5. Stable organic-inorganic hybrid multilayered photoelectrochemical cells

    NASA Astrophysics Data System (ADS)

    Park, Sun-Young; Kim, Min-gyeong; Jung, Jaehoon; Heo, Jinhee; Hong, Eun Mi; Choi, Sung Mook; Lee, Joo-Yul; Cho, Shinuk; Hong, Kihyon; Lim, Dong Chan

    2017-02-01

    The production of hydrogen from water via solar energy conversion has attracted immense attention as a potential solution for addressing energy supply issues. We demonstrated a stable and efficient organic-inorganic hybrid photoelectrochemical (H-PEC) cell. Modifying the surface energy and structure of the organic photoactive layer using multi-functional nanomaterials including -OH-modified NiO nanoparticles and reduced graphene oxide (RGO) led to a 2.8-fold enhancement of the water splitting performance in a single junction H-PEC cell. The enhanced performance was attributed to the i) improved water-wettability, ii) enhanced charge extraction property by band-edge alignment, and iii) the catalytic effect of the introduced NiO-OH nanoparticles. In addition, because of the effects of the RGO layer preventing water penetration and photo-corrosion during the oxidation of water, a distinguishable long-term stability was achieved from the H-PEC cell with an RGO capping layer. The best performance was obtained from the organic-inorganic hybrid multi-junction PEC cells consisting of the WO3 photo-anode (activated under UV irradiation) and the H-PEC cell (activated under visible light irradiation). The H-PEC cell with a WO3 photo-anode exhibited significantly enhanced stability and performance by a factor of 11.6 higher than photocurrent of the single H-PEC cell.

  6. In situ growth of monolayer porous gold nanoparticles film as high-performance SERS substrates

    NASA Astrophysics Data System (ADS)

    Song, Chunyuan; Wei, Yuhan; Da, Bingtao; Zhang, Haiting; Cong, Xing; Yang, Boyue; Yang, Yanjun; Wang, Lianhui

    2016-07-01

    Surface-enhanced Raman scattering (SERS) has recently received considerable attention as an ultrasensitive analytic technique. However, its wide application is limited by lack of excellent SERS-active substrates. In this work a SERS substrate with arrayed monolayer films of porous gold nanoparticles is prepared on a solid substrate by a facile, in situ and one-step growth approach. Specifically, the solid substrate was coated with a layer of dense positive charges first by layer-by-layer assembly, followed by patterned a PDMS film with arrayed wells on the substrate. Then the growth solution including chlorauric acid, cetyltrimethylammonium chloride, and ascorbic acid in a certain proportion was transferred into the wells for in situ and one-step growth of porous gold nanoparticles on the substrate. The growth time, feed ratio of the reagents, and repeat times of the in situ growth were studied systematically to obtain optimal parameters for preparing an optimal SERS substrate. The as-prepared optimal SERS substrate not only has good SERS performance with the enhancement factor up to ∼1.10 × 106, but also shows good uniformity and stability. The SERS substrate was further utilized to be ultrasensitive SERS-based chemical sensors for ppb-level detection of highly toxic dyfonate. The preliminary result indicates that the as-prepared SERS substrate has good SERS performance and shows a number of great potential applications in SERS-based sensors.

  7. Non-lithographic SERS substrates: tailoring surface chemistry for Au nanoparticle cluster assembly.

    PubMed

    Adams, Sarah M; Campione, Salvatore; Caldwell, Joshua D; Bezares, Francisco J; Culbertson, James C; Capolino, Filippo; Ragan, Regina

    2012-07-23

    Near-field plasmonic coupling and local field enhancement in metal nanoarchitectures, such as arrangements of nanoparticle clusters, have application in many technologies from medical diagnostics, solar cells, to sensors. Although nanoparticle-based cluster assemblies have exhibited signal enhancements in surface-enhanced Raman scattering (SERS) sensors, it is challenging to achieve high reproducibility in SERS response using low-cost fabrication methods. Here an innovative method is developed for fabricating self-organized clusters of metal nanoparticles on diblock copolymer thin films as SERS-active structures. Monodisperse, colloidal gold nanoparticles are attached via a crosslinking reaction on self-organized chemically functionalized poly(methyl methacrylate) domains on polystyrene-block-poly(methyl methacrylate) templates. Thereby nanoparticle clusters with sub-10-nanometer interparticle spacing are achieved. Varying the molar concentration of functional chemical groups and crosslinking agent during the assembly process is found to affect the agglomeration of Au nanoparticles into clusters. Samples with a high surface coverage of nanoparticle cluster assemblies yield relative enhancement factors on the order of 10⁹ while simultaneously producing uniform signal enhancements in point-to-point measurements across each sample. High enhancement factors are associated with the narrow gap between nanoparticles assembled in clusters in full-wave electromagnetic simulations. Reusability for small-molecule detection is also demonstrated. Thus it is shown that the combination of high signal enhancement and reproducibility is achievable using a completely non-lithographic fabrication process, thereby producing SERS substrates having high performance at low cost.

  8. A Nanostructured SERS Switch Based on Molecular Beacon-Controlled Assembly of Gold Nanoparticles

    PubMed Central

    Li, Yansheng; Cheng, Yaya; Xu, Liping; Du, Hongwu; Zhang, Peixun; Wen, Yongqiang; Zhang, Xueji

    2016-01-01

    In this paper, highly purified and stable gold nanoparticle (AuNP) dimers connected at the two ends of DNA linkage were prepared by a versatile method. A nanostructured, surface-enhanced Raman scattering (SERS) switching sensor system was fabricated based on the controlled organization of gold nanoparticles (AuNPs) by a DNA nanomachine through the controlled formation/deformation of SERS “hotspots”. This strategy not only opens opportunities in the precise engineering of gap distances in gold-gold nanostructures in a highly controllable and reproducible fashion, but also provides a unique ability to research the origin of SERS and sequence-specific DNA detection.

  9. Correlative SEM SERS for quantitative analysis of dimer nanoparticles.

    PubMed

    Timmermans, F J; Lenferink, A T M; van Wolferen, H A G M; Otto, C

    2016-11-14

    A Raman microscope integrated with a scanning electron microscope was used to investigate plasmonic structures by correlative SEM-SERS analysis. The integrated Raman-SEM microscope combines high-resolution electron microscopy information with SERS signal enhancement from selected nanostructures with adsorbed Raman reporter molecules. Correlative analysis is performed for dimers of two gold nanospheres. Dimers were selected on the basis of SEM images from multi aggregate samples. The effect of the orientation of the dimer with respect to the polarization state of the laser light and the effect of the particle gap size on the Raman signal intensity is observed. Additionally, calculations are performed to simulate the electric near field enhancement. These simulations are based on the morphologies observed by electron microscopy. In this way the experiments are compared with the enhancement factor calculated with near field simulations and are subsequently used to quantify the SERS enhancement factor. Large differences between experimentally observed and calculated enhancement factors are regularly detected, a phenomenon caused by nanoscale differences between the real and 'simplified' simulated structures. Quantitative SERS experiments reveal the structure induced enhancement factor, ranging from ∼200 to ∼20 000, averaged over the full nanostructure surface. The results demonstrate correlative Raman-SEM microscopy for the quantitative analysis of plasmonic particles and structures, thus enabling a new analytical method in the field of SERS and plasmonics.

  10. SERS investigations of 2,3-dibromo-1,4-naphthoquinone on silver nanoparticles.

    PubMed

    Anuratha, M; Jawahar, A; Umadevi, M; Sathe, V G; Vanelle, P; Terme, T; Meenakumari, V; Milton Franklin Benial, A

    2013-03-15

    In the present study silver nanoparticles were synthesized using a solution combustion method with glycine as fuel. The prepared silver nanoparticles show an fcc crystalline structure with a particle size of 39 nm. Surface-enhanced Raman scattering (SERS) spectra of 2,3-dibromo-1,4-naphthoquinone (DBNQ) adsorbed on silver nanoparticles were investigated. The C-C stretching modes were enhanced and they were broaden in SERS spectrum with respect to normal Raman spectrum. The spectral analysis reveals that the DBNQ adsorbed flat-on orientation on the silver surface. DFT calculations are also performed to study the vibrational features of DBNQ.

  11. Examining metal nanoparticle surface chemistry using hollow-core, photonic-crystal, fiber-assisted SERS.

    PubMed

    Eftekhari, Fatemeh; Lee, Anna; Kumacheva, Eugenia; Helmy, Amr S

    2012-02-15

    In this Letter, we demonstrate the efficacy of hollow core photonic crystal fibers (HCPCFs) as a surface-enhanced Raman spectroscopy (SERS) platform for investigating the ligand exchange process on the surface of gold nanoparticles. Raman measurements carried out using this platform show the capability to monitor minute amounts of surface ligands on gold nanoparticles used as an SERS substrate. The SERS signal from an HCPCF exhibits a tenfold enhancement compared to that in a direct sampling scheme using a cuvette. Using exchange of cytotoxic cetyltrimethylammonium bromide with α-methoxy-ω-mercaptopoly(ethylene glycol) on the surface of gold nanorods as an exemplary system, we show the feasibility of using HCPCF SERS to monitor the change in surface chemistry of nanoparticles.

  12. Photochromic organic-inorganic hybrid materials.

    PubMed

    Pardo, Rosario; Zayat, Marcos; Levy, David

    2011-02-01

    Photochromic organic-inorganic hybrid materials have attracted considerable attention owing to their potential application in photoactive devices, such as optical memories, windows, photochromic decorations, optical switches, filters or non-linear optics materials. The growing interest in this field has largely expanded the use of photochromic materials for the purpose of improving existing materials and exploring new photochromic hybrid systems. This tutorial review summarizes the design and preparation of photochromic hybrid materials, and particularly those based on the incorporation of organic molecules in organic-inorganic matrices by the sol-gel method. This is the most commonly used method for the preparation of these materials as it allows vitreous hybrid materials to be obtained at low temperatures, and controls the interaction between the organic molecule and its embedding matrix, and hence allows tailoring of the performance of the resulting devices.

  13. Passive mass transport for direct and quantitative SERS detection using purified silica encapsulated metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Shrestha, Binaya Kumar

    This thesis focuses on understanding implications of nanomaterial quality control and mass transport through internally etched silica coated nanoparticles for direct and quantitative molecular detection using surface enhanced Raman scattering (SERS). Prior to use, bare nanoparticles (partially or uncoated with silica) are removal using column chromatography to improve the quality of these nanomaterials and their SERS reproducibility. Separation of silica coated nanoparticles with two different diameters is achieved using Surfactant-free size exclusion chromatography with modest fractionation. Next, selective molecular transport is modeled and monitored using SERS and evaluated as a function of solution ionic strength, pH, and polarity. Molecular detection is achieved when the analytes first partition through the silica membrane then interact with the metal surface at short distances (i.e., less than 2 nm). The SERS intensities of unique molecular vibrational modes for a given molecule increases as the number of molecules that bind to the metal surface increases and are enhanced via both chemical and electromagnetic enhancement mechanisms as long as the vibrational mode has a component of polarizability tensor along the surface normal. SERS signals increase linearly with molecular concentration until the three-dimensional SERS-active volume is saturated with molecules. Implications of molecular orientation as well as surface selection rules on SERS intensities of molecular vibrational modes are studied to improve quantitative and reproducible SERS detection using internally etched Ag Au SiO2 nanoparticles. Using the unique vibrational modes, SERS intensities for p-aminothiophenol as a function of metal core compositions and plasmonics are studied. By understanding molecular transport mechanisms through internally etched silica matrices coated on metal nanoparticles, important experimental and materials design parameters are learned, which can be subsequently applied

  14. Flexible Hybrid Organic-Inorganic Perovskite Memory.

    PubMed

    Gu, Chungwan; Lee, Jang-Sik

    2016-05-24

    Active research has been done on hybrid organic-inorganic perovskite materials for application to solar cells with high power conversion efficiency. However, this material often shows hysteresis, which is undesirable, shift in the current-voltage curve. The hysteresis may come from formation of defects and their movement in perovskite materials. Here, we utilize the defects in perovskite materials to be used in memory operations. We demonstrate flexible nonvolatile memory devices based on hybrid organic-inorganic perovskite as the resistive switching layer on a plastic substrate. A uniform perovskite layer is formed on a transparent electrode-coated plastic substrate by solvent engineering. Flexible nonvolatile memory based on the perovskite layer shows reproducible and reliable memory characteristics in terms of program/erase operations, data retention, and endurance properties. The memory devices also show good mechanical flexibility. It is suggested that resistive switching is done by migration of vacancy defects and formation of conducting filaments under the electric field in the perovskite layer. It is believed that organic-inorganic perovskite materials have great potential to be used in high-performance, flexible memory devices.

  15. SERS active colloidal nanoparticles for the detection of small blood biomarkers using aptamers

    NASA Astrophysics Data System (ADS)

    Marks, Haley; Mabbott, Samuel; Jackson, George W.; Graham, Duncan; Cote, Gerard L.

    2015-03-01

    Functionalized colloidal nanoparticles for SERS serve as a promising multifunctional assay component for blood biomarker detection. Proper design of these nanoprobes through conjugation to spectral tags, protective polymers, and sensing ligands can provide experimental control over the sensitivity, range, reproducibility, particle stability, and integration with biorecognition assays. Additionally, the optical properties and degree of electromagnetic SERS signal enhancement can be altered and monitored through tuning the nanoparticle shape, size, material and the colloid's local surface plasmon resonance (LSPR). Aptamers, synthetic affinity ligands derived from nucleic acids, provide a number of advantages for biorecognition of small molecules and toxins with low immunogenicity. DNA aptamers are simpler and more economical to produce at large scale, are capable of greater specificity and affinity than antibodies, are easily tailored to specific functional groups, can be used to tune inter-particle distance and shift the LSPR, and their intrinsic negative charge can be utilized for additional particle stability.1,2 Herein, a "turn-off" competitive binding assay platform involving two different plasmonic nanoparticles for the detection of the toxin bisphenol A (BPA) using SERS is presented. A derivative of the toxin is immobilized onto a silver coated magnetic nanoparticle (Ag@MNP), and a second solid silver nanoparticle (AgNP) is functionalized with the BPA aptamer and a Raman reporter molecule (RRM). The capture (Ag@MNP) and probe (AgNP) particles are mixed and the aptamer binding interaction draws the nanoparticles closer together, forming an assembly that results in an increased SERS signal intensity. This aptamer mediated assembly of the two nanoparticles results in a 100x enhancement of the SERS signal intensity from the RRM. These pre-bound aptamer/nanoparticle conjugates were then exposed to BPA in free solution and the competitive binding event was monitored

  16. Studies on adsorption of carnosine on silver nanoparticles by SERS

    NASA Astrophysics Data System (ADS)

    Thomas, S.; Biswas, N.; Malkar, V. V.; Mukherjee, T.; Kapoor, S.

    2010-05-01

    The surface-enhanced Raman scattering (SERS) studies of L-carnosine was carried out in aqueous silver sol at pH ˜ 9 and compared with the normal Raman spectrum of the molecule. The experimentally observed Raman bands were assigned based on the results of DFT calculations. Significant changes in the relative intensity are seen in the SERS spectrum when compared to the normal Raman spectrum. The studies suggest that the interaction of carnosine is primarily through the carboxylate group with the imidazole ring in an upright position with respect to the silver surface and the alanine moiety assuming a parallel orientation with the surface where NH 2 group is close to the silver surface.

  17. Organosilica: Chemistry of Mesoporous Organosilica in Nanotechnology: Molecularly Organic-Inorganic Hybridization into Frameworks (Adv. Mater. 17/2016).

    PubMed

    Chen, Yu; Shi, Jianlin

    2016-05-01

    Organic-inorganic hybrid materials can combine the advantages of organic and inorganic materials, and overcome their drawbacks accordingly. On page 3235, Y. Chen and J. L. Shi review and discuss research progress on the design, synthesis, structure, and composition control of organic-inorganic hybrid mesoporous organosilica nanoparticles (MONs). Extensive applications of MONs in nanotechnology, mainly in nanomedicine, nanocatalysis and nanofabrication are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. DNA origami based Au-Ag-core-shell nanoparticle dimers with single-molecule SERS sensitivity

    NASA Astrophysics Data System (ADS)

    Prinz, J.; Heck, C.; Ellerik, L.; Merk, V.; Bald, I.

    2016-03-01

    DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled.DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled. Electronic supplementary information (ESI) available: Additional information about materials and methods, designs of DNA origami templates, height profiles, additional SERS spectra, assignment of DNA

  19. Combined organic-inorganic fouling of forward osmosis hollow fiber membranes.

    PubMed

    Arkhangelsky, Elizabeth; Wicaksana, Filicia; Tang, Chuyang; Al-Rabiah, Abdulrahman A; Al-Zahrani, Saeed M; Wang, Rong

    2012-12-01

    This research focused on combined organic-inorganic fouling and cleaning studies of forward osmosis (FO) membranes. Various organic/inorganic model foulants such as sodium alginate, bovine serum albumin (BSA) and silica nanoparticles were applied to polyamide-polyethersulfone FO hollow fiber membranes fabricated in our laboratory. In order to understand all possible interactions, experiments were performed with a single foulant as well as combinations of foulants. Experimental results suggested that the degree of FO membrane fouling could be promoted by synergistic effect of organic foulants, the presence of divalent cations, low cross-flow velocity and high permeation drag force. The water flux of fouled FO hollow fibers could be fully restored by simple physical cleaning. It was also found that hydrodynamic regime played an important role in combined organic-inorganic fouling of FO membranes.

  20. In-situ partial sintering of gold-nanoparticle sheets for SERS applications.

    PubMed

    He, Jinbo; Lin, Xiao-Min; Divan, Ralu; Jaeger, Heinrich M

    2011-12-16

    A new, versatile substrate design for surface-enhanced Raman spectroscopy (SERS) is introduced that provides better illumination and collection efficiency than other solid substrates. It uses sheets of 5 nm diameter gold nanoparticles that are draped by drying-mediated self-assembly onto 100 nm thick silicon nitride membranes. During laser illumination, partial in-situ sintering of the nanoparticles into larger structures with tiny gaps (≈2 nm) greatly increases the SERS enhancement factor. The detection of 1 pM of p-mercaptoaniline and 1 fg of 2,4-dinitrotoluene is demonstrated. The use of self-assembled nanoparticle sheets furthermore makes it possible to perform SERS detection in situ on top of a probe solution droplet. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Green synthesis of gold nanoparticles by Allium sativum extract and their assessment as SERS substrate

    NASA Astrophysics Data System (ADS)

    Coman, Cristina; Leopold, Loredana Florina; Rugină, Olivia Dumitriţa; Barbu-Tudoran, Lucian; Leopold, Nicolae; Tofană, Maria; Socaciu, Carmen

    2014-01-01

    A green synthesis was used for preparing stable colloidal gold nanoparticles by using Allium sativum aqueous extract both as reducing and capping agent. The obtained nanoparticles were characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy. Moreover, their potential to be used as surface-enhanced Raman scattering (SERS) substrate was investigated. The obtained gold nanoparticles have spherical shape with mean diameters of 9-15 nm (depending on the amount of reducing agent used under boiling conditions) and are stable up to several months. FTIR spectroscopy shows that the nanoparticles are capped by protein molecules from the extract. The protein shell offers a protective coating, relatively impervious to external molecules, thus, rendering the nanoparticles stable and quite inert. These nanoparticles have the potential to be used as SERS substrates, both in solution and inside human fetal lung fibroblast HFL-1 living cells. We were able to demonstrate both the internalization of the nanoparticles inside HFL-1 cells and their ability to preserve the SERS signal after cellular internalization.

  2. Bidimensional assemblies of nonspherical gold nanoparticles for SERS analysis of biomolecules

    NASA Astrophysics Data System (ADS)

    Matteini, Paolo; de Angelis, Marella; Ulivi, Lorenzo; Centi, Sonia; Pini, Roberto

    2015-03-01

    Direct SERS analysis of proteins has been mainly devoted to the characterization of short peptide fragments or to the prosthetic group of metallo-proteins due to their strong SERS response. Nonetheless, this perspective restricts the investigation to very limited peptide sequences and appears of scarce interest for a thorough characterization of the protein. We tried to overcome the above limitations by setting-up an effective platform for the structural SERS detection of proteins. Our proposal escapes the needs of a preliminary modification of the biomolecule and confers rapidity and reproducibility to the analysis. Optimal results are achieved by the use of nonspherical tipped metallic nanostructures with controlled architectural parameters and their assembly into organized bidimensional arrays including a regular distribution of hot spots for protein entrapment and detection. The investigation evidenced that both the contact points between nanoparticle corners and the holes at the interface between nanoparticles are responsible for substantial SERS activity.

  3. Highly reproducible and uniform SERS substrates based on Ag nanoparticles with optimized size and gap

    NASA Astrophysics Data System (ADS)

    Bai, Yiming; Yan, Lingling; Wang, Jun; Su, Lin; Chen, Nuofu; Tan, Zhanao

    2017-02-01

    It's quite necessary to fabricate reproducible and uniform surface-enhanced Raman scattering (SERS) composite substrate with high enhancement factor simply. Therefore, in this work, in order to obtain the SERS substrates with optimized size and gap, Ag films with different thickness deposited by magnetron sputtering and following annealing are performed. The results both elucidate the function relationship between the size, gap of nanoparticles and the thickness of Ag films, and ascertain the optimized parameters for silver nanoparticles on the basis of finite-difference time-domain simulation, the SERS signal using graphene and Rhodamine 6G (R6G) as probe molecules for Ag-NPs/Si substrates. Moreover, our findings highlight the Ag NPs with optimized size and gap as SERS substrates present high reproducibility and uniformity.

  4. Nanoscale investigation of organic - inorganic halide perovskites

    NASA Astrophysics Data System (ADS)

    Cacovich, S.; Divitini, G.; Vrućinić, M.; Sadhanala, A.; Friend, R. H.; Sirringhaus, H.; Deschler, F.; Ducati, C.

    2015-10-01

    Over the last few years organic - inorganic halide perovskite-based solar cells have exhibited a rapid evolution, reaching certified power conversion efficiencies now surpassing 20%. Nevertheless the understanding of the optical and electronic properties of such systems on the nanoscale is still an open problem. In this work we investigate two model perovskite systems (based on iodine - CH3NH3PbI3 and bromine - CH3NH3PbBr3), analysing the local elemental composition and crystallinity and identifying chemical inhomogeneities.

  5. Effect of the size of silver nanoparticles on SERS signal enhancement

    NASA Astrophysics Data System (ADS)

    He, Rui Xiu; Liang, Robert; Peng, Peng; Norman Zhou, Y.

    2017-08-01

    The localized surface plasmon resonance arising from plasmonic materials is beneficial in solution-based and thin-film sensing applications, which increase the sensitivity of the analyte being tested. Silver nanoparticles from 35 to 65 nm in diameter were synthesized using a low-temperature method and deposited in a monolayer on a (3-aminopropyl)triethoxysilane (APTES)-functionalized glass slide. The effect of particle size on monolayer structure, optical behavior, and surface-enhanced Raman scattering (SERS) is studied. While increasing particle size decreases particle coverage, it also changes the localized surface plasmon resonance and thus the SERS activity of individual nanoparticles. Using a laser excitation wavelength of 633 nm, the stronger localized surface plasmon resonance coupling to this excitation wavelength at larger particle sizes trumps the loss in surface coverage, and greater SERS signals are observed. The SERS signal enhancement accounts for the higher SERS signal, which was verified using a finite element model of a silver nanoparticle dimer with various nanoparticle sizes and separation distances.

  6. The fabrication of polymer-nanocone-based 3D Au nanoparticle array and its SERS performance

    NASA Astrophysics Data System (ADS)

    Zhao, Wenning; Wu, Yiyao; Liu, Xiaoguang; Xu, Yebin; Wang, Shuangbao; Xu, Zhimou

    2017-01-01

    By combining conical-pore-AAO template and NIL technology, we realized the transfer of three-dimensional nanoparticle array to polymer materials. Au nanoparticles were deposited on the surface of conical-pore-AAO template, then the nanostructure was duplicated onto the polymer wafer via NIL method and the nanoparticles were inlaid onto the nanocones. Polymer-nanocone-based 3D Au nanoparticle array was obtained. The product possesses excellent flexibility and transparency in visual and infrared range. As a new class of SERS substrate, the product exhibits excellent sensitivity and reproducibility. Compared with the traditional SERS substrates, it provides unique advantages, such as being flexible, transparent, lightweight, portable, easily handled and low cost.

  7. Preparation of graphene-Ag nanoparticles hybrids and their SERS activities

    NASA Astrophysics Data System (ADS)

    Wang, Xinyu; Wang, Ning; Gong, Tiancheng; Zhu, Yong; Zhang, Jie

    2016-11-01

    Surface-enhanced Raman scattering (SERS) substrates based on graphene and Ag nanoparticles hybrid structures with low cost, high uniformity were prepared by a standard process of immobilization of silver nanoparticles with 3-aminopropyltrimethoxysilane (APTMS). Thermal annealing was used for removing residual APTMS and adjusting the morphology of silver nanoparticles, and the effectiveness of this method was verified experimentally. The influence of annealing temperature, dipping duration, and APTMS volume on the distribution of Ag nanoparticles and Raman enhancement was investigated experimentally and analyzed in detail. Our samples were prepared under the preparation conditions of 10% ν/ν APTMS, dipping time of 48 h, annealing temperature of 450 °C, duration of 30 min, and Ar flow rate of 40 sccm. SERS activities with enhancement of 107 and relative standard deviation of <20% were observed using rhodamine 6G (R6G) as probe molecule with a concentration of 10-6 M and 10-7 M.

  8. Fabrication of flexible and porous surface enhanced raman scattering (SERS) substrates using nanoparticle inks

    NASA Astrophysics Data System (ADS)

    Figueroa, Manuel; Pourrezaei, Kambiz; Tyagi, Somdev

    2012-07-01

    In order to analyze a sample using SERS, the analyte has to be brought in intimate contact with the substrate. This can be problematic when, let's say, the molecules of interest in trace amounts are located in large volumes. For example a biotoxin aerosol in a large room or a trace amount of bio-hazardous substances mixed in large volumes of water or other liquids. In principle it is possible to filter out the molecules of interest and then deposit them on the SERS substrate for further analyses. In practice this is very cumbersome and therefore is rarely used. Here we discuss flexible and porous SERS substrates that have been fabricated by depositing silver nano-particle inks on woven or spun fabrics made of glass fiber or cellulose followed by thermal annealing at 170-200°C for 10-15 minutes. Use of microwave absorption at about 10 GHz in the polymer-nanoparticle matrix to monitor the sintering process and to optimize the SERS amplification is also discussed. By varying the annealing time, different levels of nanoparticle clustering and the consequent SERS amplification can be achieved. Sampling of large volumes using the SERS filter substrates to detect airborne molecules is also discussed.

  9. Chitosan-coated anisotropic silver nanoparticles as a SERS substrate for single-molecule detection

    NASA Astrophysics Data System (ADS)

    Potara, Monica; Baia, Monica; Farcau, Cosmin; Astilean, Simion

    2012-02-01

    Surface-enhanced Raman spectroscopy (SERS) is a technique that has become widely used for identifying and providing structural information about molecular species in low concentration. There is an ongoing interest in finding optimum particle size, shape and spatial distribution for optimizing the SERS substrates and pushing the sensitivity toward the single-molecule detection limit. This work reports the design of a novel, biocompatible SERS substrate based on small clusters of anisotropic silver nanoparticles embedded in a film of chitosan biopolymer. The SERS efficiency of the biocompatible film is assessed by employing Raman imaging and spectroscopy of adenine, a significant biological molecule. By combining atomic force microscopy with SERS imaging we find that the chitosan matrix enables the formation of small clusters of silver nanoparticles, with junctions and gaps that greatly enhance the Raman intensities of the adsorbed molecules. The study demonstrates that chitosan-coated anisotropic silver nanoparticle clusters are sensitive enough to be implemented as effective plasmonic substrates for SERS detection of nonresonant analytes at the single-molecule level.

  10. Modification of TiO2 Nanoparticles with Oleyl Phosphate via Phase Transfer in the Toluene-Water System and Application of Modified Nanoparticles to Cyclo-Olefin-Polymer-Based Organic-Inorganic Hybrid Films Exhibiting High Refractive Indices.

    PubMed

    Takahashi, Shiori; Hotta, Shuhei; Watanabe, Akira; Idota, Naokazu; Matsukawa, Kimihiro; Sugahara, Yoshiyuki

    2017-01-18

    Oleyl-phosphate-modified TiO2 nanoparticles (OP_TiO2) were prepared via phase transfer from an aqueous phase containing dispersed TiO2 nanoparticles to a toluene phase containing oleyl phosphate (OP, a mixture of monoester and diester), and employed for the preparation of OP_TiO2/cyclo-olefin polymer (COP) hybrid films with high-refractive indices. The modification of TiO2 by OP was essentially completed by reaction at room temperature for 8 h, and essentially all the TiO2 nanoparticles in the aqueous phase were transferred to the toluene phase. The infrared and solid-state (13)C cross-polarization and magic-angle spinning (CP/MAS) NMR spectrum of OP_TiO2 showed the presence of oleyl groups originating from oleyl phosphate. The solid-state (31)P MAS NMR spectrum of OP_TiO2 exhibited new signals at -1.4, 2.1, and 4.8 ppm, indicating the formation of Ti-O-P bonds. CHN and inductively coupled plasma analyses revealed that the major species bound to the TiO2 surface was tridentate CH3(CH2)7CH═CH(CH2)8P(OTi)3. These results clearly indicate that the surfaces of the TiO2 nanoparticles were modified by OP moieties via phase transfer. OP_TiO2/COP hybrid films exhibited excellent optical transparency up to 19.1 vol % TiO2 loading, and the light transmittance of the hybrid films with 19.1 vol % TiO2 loading was 99.8% at 633 nm. The refractive index of these hybrid films rose to 1.83.

  11. Monitoring the coordination of amine ligands on silver nanoparticles using NMR and SERS.

    PubMed

    Cure, Jérémy; Coppel, Yannick; Dammak, Thameur; Fazzini, Pier Francesco; Mlayah, Adnen; Chaudret, Bruno; Fau, Pierre

    2015-02-03

    Low size dispersity silver nanoparticles (ca. 6 nm) have been synthesized by the hydrogenolysis of silver amidinate in the presence of hexadecylamine. Combining NMR techniques with SERS and DFT modeling, it is possible to observe an original stabilization mechanism. Amidine moiety is strongly coordinated to the Ag(0) nanoparticles surface whereas HDA ligand is necessary to prevent agglomeration, although it is only weakly interacting with the surface.

  12. Nanomolar detection of glucose using SERS substrates fabricated with albumin coated gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Perez-Mayen, Leonardo; Oliva, Jorge; Salas, P.; de La Rosa, Elder

    2016-06-01

    This work presents the design of substrates for Surface Enhanced Raman Scattering (SERS) using star-like gold nanoparticles synthesized by a wet chemical method. The SERS substrates were used for glucose detection for concentrations as low as 10-7 M, which represents an enhancement factor (EF) of 109, as a result of the hot spot formed by the spike termination and appropriate distribution of the gold nanoparticles. An improvement of two orders of magnitude was obtained by coating the gold nanoparticles with albumin with the configuration: glass/Au nanoparticles/albumin. In this case the lowest detection was at a concentration of 10-9 M for an EF of 1011. The albumin molecule allowed us to enhance the Raman signal because of the formation of peptide bonds (COOH-NH2) generated due to the interaction of glucose with albumin, and the appropriate separation distance between the glucose molecules and gold nanoparticles. The presence of such peptide conjugates was confirmed by FTIR spectra. Thus, our results suggest that our SERS substrates can be useful for the detection of very low concentrations of glucose, which is important for the diagnosis of diabetes in the field of medicine.This work presents the design of substrates for Surface Enhanced Raman Scattering (SERS) using star-like gold nanoparticles synthesized by a wet chemical method. The SERS substrates were used for glucose detection for concentrations as low as 10-7 M, which represents an enhancement factor (EF) of 109, as a result of the hot spot formed by the spike termination and appropriate distribution of the gold nanoparticles. An improvement of two orders of magnitude was obtained by coating the gold nanoparticles with albumin with the configuration: glass/Au nanoparticles/albumin. In this case the lowest detection was at a concentration of 10-9 M for an EF of 1011. The albumin molecule allowed us to enhance the Raman signal because of the formation of peptide bonds (COOH-NH2) generated due to the

  13. Antitags: SERS-encoded nanoparticle assemblies that enable single-spot multiplex protein detection.

    PubMed

    Guarrotxena, Nekane; Bazan, Guillermo C

    2014-03-26

    Simultaneous detection of multiple proteins on a single spot can be efficiently achieved by using multiplexed surface-enhanced Raman spectroscopy (SERS)-encoded nanoparticle 'antitags' consisting of poly(ethylene glycol) (PEG)-protected silver dimers (and higher aggregates) and antibody-tagging entities. The effective SERS-based multivariate deconvolution approach guarantees an accurate and successful distinguishable identification of single and multiple proteins in complex samples. Their potential application in multiplexed SERS bioimaging technology can be easily envisaged. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. SERS detection of low-concentration adenosine by silver nanoparticles on silicon nanoporous pyramid arrays structure

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Man, B. Y.; Jiang, S. Z.; Yang, C.; Liu, M.; Chen, C. S.; Xu, S. C.; Qiu, H. W.; Li, Z.

    2015-08-01

    A novel surface-enhanced Raman spectroscopy (SERS) substrate based on uniform silver nanoparticles/silicon nanoporous pyramid arrays (Ag/PS) is prepared and SERS behaviors to adenosine are discussed and compared. With a low concentration of 10-7 M, the characteristic Raman bands of adenosine demonstrate the significantly high SERS sensitivity of the prepared Ag/PS substrate. A reasonable linear correlation is obtained between the intensity of SERS signal and the adenosine concentration from 10-2 to 10-7M in log scale. These results imply that the Ag/PS with regular pyramids array might be an effective substrate for performing label-free sensitive SERS detections of biomolecule.

  15. Chiral ionic liquid monolayer-stabilized gold nanoparticles: synthesis, self-assembly, and application to SERS.

    PubMed

    Bai, Xiangtao; Li, Xinwei; Zheng, Liqiang

    2010-07-20

    Chiral ionic liquid monolayer-stabilized gold nanoparticles were synthesized in a two-phase liquid-liquid system and found to self-assemble into ringlike structures at the air/water interface. Control experiments with long-chain ILs revealed that the molecular structure of the CIL significantly affects the formation of the gold nanoparticle ring structures. A possible mechanism based on Marangoni-Bénard convection in evaporating droplets was proposed. These gold nanoparticle structures were shown to yield a large SERS enhancement for Rhodamine 6G.

  16. Hyperbranched polymers and dendrimers as templates for organic/inorganic hybrid nanomaterials.

    PubMed

    Huang, Xinhua; Zheng, Sudan; Kim, Il

    2014-02-01

    This paper reviews the recent research and development of hyperbranched polymers (HPs) and dendrimers, and their use as templates for organic-inorganic hybrid nanomaterials. Hyperbranched polymers (HPs) are highly branched macromolecules with three-dimensional globular structures featuring unique properties such as low viscosity, high solubility, and a large number of terminal functional groups compared to their linear analogs. They are easily prepared by (1) condensation polymerization, (2) self-condensing vinyl copolymerization (SCVCP), and (3) ring-opening multibranch polymerization methods. Organic-inorganic hybrid nanomaterials are synthesized by a template approach using HPs/dendrimers. Monometallic, bimetallic (alloy and core/shell), semiconductor, and metal oxide nanoparticles have been prepared by this route. The dendrimer component of these composites serves not only as a template for preparing the nanoparticles but also as a stabilizer for the nanoparticles.

  17. In situ SERS detection of emulsifiers at lipid interfaces using label-free amphiphilic gold nanoparticles.

    PubMed

    Li, Yue; Driver, Michael; Winuprasith, Thunnalin; Zheng, Jinkai; McClements, David Julian; He, Lili

    2014-10-21

    Herein, we fabricated amphiphilic gold nanoparticles (GNPs) that can self-assemble at oil-water interfaces. We applied those GNPs for in situ SERS detection of emulsifier molecules within the interfacial region of oil in water (O/W) emulsion systems.

  18. SERS detection and boron delivery to cancer cells using carborane labelled nanoparticles.

    PubMed

    Kennedy, David C; Duguay, Dominique R; Tay, Li-Lin; Richeson, Darrin S; Pezacki, John P

    2009-11-28

    Water-soluble carborane functionalized nanoparticles also co-functionalized with targeting antibodies have been prepared. We demonstrate tumour cell targeting with anti-EGFR antibodies and delivery of a high concentration of boron using SERS imaging. This suggests these materials have a therapeutic potential in addition to multimodal imaging capabilities.

  19. SERS substrates fabricated with star-like gold nanoparticles for zeptomole detection of analytes

    NASA Astrophysics Data System (ADS)

    Pérez-Mayen, Leonardo; Oliva, Jorge; Torres-Castro, Alejandro; de La Rosa, Elder

    2015-05-01

    This work presents the design of substrates for Surface Enhanced Raman Scattering (SERS) using star-like gold nanoparticles which were synthesized using a wet chemical method and functionalized with 1-dodecanethiol. This molecule allowed us to obtain a spacing of ~2.6 nm among gold stars, which promoted the generation of SERS hotspots for single molecule detection. The gold nanoparticles were deposited on silicon substrates or on gold coated silicon substrates by using the Langmuir-Blodgett method which permitted the zeptomole detection of Rhodamine B (total moles per laser spot area). The Raman enhancement factor (EF) achieved for this level of detection was 1012, and was obtained on the SERS substrate fabricated with the configuration: Si/Au film/Au nanoparticles. Raman spectra of the molecules TWEEN 20 and p-terphenyl were also measured in order to elucidate the effect of the molecule's length on the enhancement factor. According to these results, our SERS substrates without the gold film are useful for a minimum detection level of ~10-14 moles of analytes with sizes equal to or less than 1.3 nm and ~10-18 moles of analytes with the gold film (total moles per sample).This work presents the design of substrates for Surface Enhanced Raman Scattering (SERS) using star-like gold nanoparticles which were synthesized using a wet chemical method and functionalized with 1-dodecanethiol. This molecule allowed us to obtain a spacing of ~2.6 nm among gold stars, which promoted the generation of SERS hotspots for single molecule detection. The gold nanoparticles were deposited on silicon substrates or on gold coated silicon substrates by using the Langmuir-Blodgett method which permitted the zeptomole detection of Rhodamine B (total moles per laser spot area). The Raman enhancement factor (EF) achieved for this level of detection was 1012, and was obtained on the SERS substrate fabricated with the configuration: Si/Au film/Au nanoparticles. Raman spectra of the molecules

  20. Zirconium umbelliferonephosphate - A luminescent organic-inorganic hybrid nanomaterial

    NASA Astrophysics Data System (ADS)

    Roming, Marcus; Feldmann, Claus

    2011-03-01

    Zirconium umbelliferonephosphate (ZrO(UFP)) is prepared by nucleation in the ionic liquid [MeBu 3N][NTf 2]. According to electron microscopy the resulting nanoparticles exhibit mean particle diameters of about 50 nm. The organic-inorganic hybrid material ZrO(UFP) shows blue emission upon UV-excitation. Luminescence originates from the organic dye and is highly intense due to the molar amount of luminescent centers per nanoparticle. The as-prepared material turns out to be non-crystalline. Therefore, its chemical composition is validated by infrared spectroscopy, thermogravimetry, energy-dispersive X-ray analysis and elemental analysis. The results (i.e., thermal decomposition, Zr:P ratio, C-/H-concentration) are in accordance to the composition of ZrO(UFP). Upon addition of acid phosphatase the luminescence intensity of ZrO(UFP) is significantly increased due to enzymatic hydrolysis accompanied by a release of non-bound umbelliferone. Both aspects - the increase in luminescence intensity as well as the release of umbelliferone - might be of future interest regarding biomedical application of ZrO(UFP) nanoparticles.

  1. Multilayer silver nanoparticles-modified optical fiber tip for high performance SERS remote sensing.

    PubMed

    Andrade, Gustavo F S; Fan, MeiKun; Brolo, Alexandre G

    2010-06-15

    This work presents the construction and optimization of nanoparticles-modified optical fiber tip (NPs-MOFT) devices for remote sensing by surface-enhanced Raman scattering (SERS). Silver nanoparticles (Ag-NPs) were self-assembled on optical fiber tips through a "layer-by-layer" procedure. It is shown that the SERS performance is at optimum when 5 "layers" of 50 nm Ag-NPs were deposited on the optical fiber tip. Using the optimized Ag-NPs-MOFT device, it was possible to detect 200 nM of the R6G dye in remote sensing mode (backscattering through the fiber). It was also possible to detect dye molecules with different structures and charges at the micro-molar concentration level, including anions, cations and neutral species. It can be envisioned that the Ag-NPs-MOFT device reported in this work can be further developed for SERS-based remote biosensing.

  2. Preparation of gold nanoparticles-agarose gel composite and its application in SERS detection

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoyuan; Xia, Yu; Ni, Lili; Song, Liangjing; Wang, Zhouping

    2014-03-01

    Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Nanocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nanocomposites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules (NBA, MBA, 1NAT). Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal. Furthermore, the gel could be cleaned with washing solution and recycling could be achieved for Raman detection.

  3. Preparation of gold nanoparticles-agarose gel composite and its application in SERS detection.

    PubMed

    Ma, Xiaoyuan; Xia, Yu; Ni, Lili; Song, Liangjing; Wang, Zhouping

    2014-01-01

    Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Nanocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nanocomposites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules (NBA, MBA, 1NAT). Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal. Furthermore, the gel could be cleaned with washing solution and recycling could be achieved for Raman detection.

  4. Improving SERS activity of inositol hexaphosphate capped silver nanoparticles: Fe3+ as a switcher.

    PubMed

    Guo, Xiaoyu; Fu, Yichen; Fu, Shuyue; Wang, Hui; Yang, Tianxi; Wen, Ying; Yang, Haifeng

    2014-07-21

    Inositol hexaphosphate (IP6) capped silver nanoparticles (IP6@AgNPs) were fabricated as surface-enhanced Raman scattering (SERS) active substrates. SERS activity of IP6@AgNPs could be further improved via adding due amounts of Fe(3+) to form Fe(3+)-IP6@AgNPs. The mechanism of Fe(3+)-induced SERS improvement of IP6@AgNPs can be attributed to the strong interaction of IP6 and Fe(3+), which leads to controllable adjustment of the gap among neighboring nanoparticles to produce "hot spots". The above mechanism was confirmed with ultraviolet-visible (UV-vis) spectroscopy, transmission electron microscope (TEM), dynamic light scattering (DLS), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Such Fe(3+)-IP6@AgNPs-based SERS system was used to detect Rhodamine 6G (R6G) down to the trace level of 10(-10) mol L(-1). Besides, New Fuchsin (NF) was also used as a Raman probe to calculate the enhancement factor (EF) of IP6@AgNPs without and with Fe(3+). The SERS activity of IP6@AgNPs happened extreme decrease after one-year storage and could be recovered to great extent aided by the addition of Fe(3+). The Fe(3+) optimized IP6@AgNPs system could be applied to detect thymine at trace level by SERS.

  5. Preparation and evaluation of nanocellulose-gold nanoparticle nanocomposites for SERS applications.

    PubMed

    Wei, Haoran; Rodriguez, Katia; Renneckar, Scott; Leng, Weinan; Vikesland, Peter J

    2015-08-21

    Nanocellulose is of research interest due to its extraordinary optical, thermal, and mechanical properties. The incorporation of guest nanoparticles into nanocellulose substrates enables production of novel nanocomposites with a broad range of applications. In this study, gold nanoparticle/bacterial cellulose (AuNP/BC) nanocomposites were prepared and evaluated for their applicability as surface-enhanced Raman scattering (SERS) substrates. The nanocomposites were prepared by citrate mediated in situ reduction of Au(3+) in the presence of a BC hydrogel at 303 K. Both the size and morphology of the AuNPs were functions of the HAuCl4 and citrate concentrations. At high HAuCl4 concentrations, Au nanoplates form within the nanocomposites and are responsible for high SERS enhancements. At lower HAuCl4 concentrations, uniform nanospheres form and the SERS enhancement is dependent on the nanosphere size. The time-resolved increase in the SERS signal was probed as a function of drying time with SERS 'hot-spots' primarily forming in the final minutes of nanocomposite drying. The application of the AuNP/BC nanocomposites for detection of the SERS active dyes MGITC and R6G as well as the environmental contaminant atrazine is illustrated as is its use under low and high pH conditions. The results indicate the broad applicability of this nanocomposite for analyte detection.

  6. Quantitative detection of liver-relevant biomarkers by SERS-immunolabeled gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Payne, William Mark

    Lab-on-a-chip technology has the potential to rapidly change the way experiments are conducted in a variety of fields ranging from medicine to environmental science. Specifically, sensors, detectors, and monitoring devices are increasingly being miniaturized to perform many experiments or measurements on a single chip. In this research, we develop an immunolabeled gold nanoparticle complex capable of detecting liver organoid biomarkers intended for use in a microfluidic device. Human Serum Albumin (HSA) and alpha-Glutathione S-Transferase (alpha-GST) are liver biomarkers that indicate liver health and damage respectively. Herein we demonstrate detection of the liver organoid biomarkers at nanomolar concentrations. Through plasmonic coupling induced by aggregation in the presence of analyte, the SERS signal obtained from the nanoparticles is dramatically increased. Furthermore, detection is demonstrated in a simple fluidic device to show the feasibility of implementing an optimized SERS-immunolabeled nanoparticle for translational application.

  7. Monitoring Early-Stage Nanoparticle Assembly in Microdroplets by Optical Spectroscopy and SERS.

    PubMed

    Salmon, Andrew R; Esteban, Ruben; Taylor, Richard W; Hugall, James T; Smith, Clive A; Whyte, Graeme; Scherman, Oren A; Aizpurua, Javier; Abell, Chris; Baumberg, Jeremy J

    2016-04-06

    Microfluidic microdroplets have increasingly found application in biomolecular sensing as well as nanomaterials growth. More recently the synthesis of plasmonic nanostructures in microdroplets has led to surface-enhanced Raman spectroscopy (SERS)-based sensing applications. However, the study of nanoassembly in microdroplets has previously been hindered by the lack of on-chip characterization tools, particularly at early timescales. Enabled by a refractive index matching microdroplet formulation, dark-field spectroscopy is exploited to directly track the formation of nanometer-spaced gold nanoparticle assemblies in microdroplets. Measurements in flow provide millisecond time resolution through the assembly process, allowing identification of a regime where dimer formation dominates the dark-field scattering and SERS. Furthermore, it is shown that small numbers of nanoparticles can be isolated in microdroplets, paving the way for simple high-yield assembly, isolation, and sorting of few nanoparticle structures.

  8. Gold nanoparticle decorated electrospun nanofibers: A 3D reproducible and sensitive SERS substrate

    NASA Astrophysics Data System (ADS)

    Liu, Zhicheng; Yan, Zhaodong; Jia, Lu; Song, Ping; Mei, Linyu; Bai, Lu; Liu, Yaqing

    2017-05-01

    The design and fabrication of three-dimensional (3D) nanostructures with fascinating SERS performance have drawn much attention in the field of materials science and nanotechnology. In this work, 3D poly (acrylic acid) (PAA)/poly (vinyl alcohol) (PVA) nanofibrous membrane was used as templates for the electrostatic assembly of gold nanoparticles. The PAA/PVA electrospun nanofibers were crosslinked using a simple thermal treatment, which would prevent the nanofibers from dissolution in the nanoparticle solution. It was found that the gold nanoparticles were uniformly immobilized on the nanofibers, causing high reproducibility of this SERS substrate. The nanocomposite membrane also showed high sensibility for the detection of trace amount of analytes such as 4-aminothiophenol and Rhodamine 6G.

  9. Ion conducting organic/inorganic hybrid polymers

    NASA Technical Reports Server (NTRS)

    Meador, Maryann B. (Inventor); Kinder, James D. (Inventor)

    2010-01-01

    This invention relates to a series of organic/inorganic hybrid polymers that are easy to fabricate into dimensionally stable films with good ion-conductivity over a wide range of temperatures for use in a variety of applications. The polymers are prepared by the reaction of amines, preferably diamines and mixtures thereof with monoamines with epoxy-functionalized alkoxysilanes. The products of the reaction are polymerized by hydrolysis of the alkoxysilane groups to produce an organic-containing silica network. Suitable functionality introduced into the amine and alkoxysilane groups produce solid polymeric membranes which conduct ions for use in fuel cells, high-performance solid state batteries, chemical sensors, electrochemical capacitors, electro-chromic windows or displays, analog memory devices and the like.

  10. Ion-Conducting Organic/Inorganic Polymers

    NASA Technical Reports Server (NTRS)

    Kinder, James D.; Meador, Mary Ann B.

    2007-01-01

    Ion-conducting polymers that are hybrids of organic and inorganic moieties and that are suitable for forming into solid-electrolyte membranes have been invented in an effort to improve upon the polymeric materials that have been used previously for such membranes. Examples of the prior materials include perfluorosulfonic acid-based formulations, polybenzimidazoles, sulfonated polyetherketone, sulfonated naphthalenic polyimides, and polyethylene oxide (PEO)-based formulations. Relative to the prior materials, the polymers of the present invention offer greater dimensional stability, greater ease of formation into mechanically resilient films, and acceptably high ionic conductivities over wider temperature ranges. Devices in which films made of these ion-conducting organic/inorganic polymers could be used include fuel cells, lithium batteries, chemical sensors, electrochemical capacitors, electrochromic windows and display devices, and analog memory devices. The synthesis of a polymer of this type (see Figure 1) starts with a reaction between an epoxide-functionalized alkoxysilane and a diamine. The product of this reaction is polymerized by hydrolysis and condensation of the alkoxysilane group, producing a molecular network that contains both organic and inorganic (silica) links. The silica in the network contributes to the ionic conductivity and to the desired thermal and mechanical properties. Examples of other diamines that have been used in the reaction sequence of Figure 1 are shown in Figure 2. One can use any of these diamines or any combination of them in proportions chosen to impart desired properties to the finished product. Alternatively or in addition, one could similarly vary the functionality of the alkoxysilane to obtain desired properties. The variety of available alkoxysilanes and diamines thus affords flexibility to optimize the organic/inorganic polymer for a given application.

  11. Reliable Quantitative SERS Analysis Facilitated by Core-Shell Nanoparticles with Embedded Internal Standards.

    PubMed

    Shen, Wei; Lin, Xuan; Jiang, Chaoyang; Li, Chaoyu; Lin, Haixin; Huang, Jingtao; Wang, Shuo; Liu, Guokun; Yan, Xiaomei; Zhong, Qiling; Ren, Bin

    2015-06-15

    Quantitative analysis is a great challenge in surface-enhanced Raman scattering (SERS). Core-molecule-shell nanoparticles with two components in the molecular layer, a framework molecule to form the shell, and a probe molecule as a Raman internal standard, were rationally designed for quantitative SERS analysis. The signal of the embedded Raman probe provides effective feedback to correct the fluctuation of samples and measuring conditions. Meanwhile, target molecules with different affinities can be adsorbed onto the shell. The quantitative analysis of target molecules over a large concentration range has been demonstrated with a linear response of the relative SERS intensity versus the surface coverage, which has not been achieved by conventional SERS methods.

  12. Comprehensive spectral endoscopy of topically applied SERS nanoparticles in the rat esophagus.

    PubMed

    Wang, Yu W; Khan, Altaz; Leigh, Steven Y; Wang, Danni; Chen, Ye; Meza, Daphne; Liu, Jonathan T C

    2014-09-01

    The early detection and biological investigation of esophageal cancer would benefit from the development of advanced imaging techniques to screen for the molecular changes that precede and accompany the onset of cancer. Surface-enhanced Raman scattering (SERS) nanoparticles (NPs) have the potential to improve cancer detection and the investigation of cancer progression through the sensitive and multiplexed phenotyping of cell-surface biomarkers. Here, a miniature endoscope featuring rotational scanning and axial pull back has been developed for 2D spectral imaging of SERS NPs topically applied on the lumenal surface of the rat esophagus. Raman signals from low-pM concentrations of SERS NP mixtures are demultiplexed in real time to accurately calculate the concentration and ratio of the NPs. Ex vivo and in vivo experiments demonstrate the feasibility of topical application and imaging of multiplexed SERS NPs along the entire length of the rat esophagus.

  13. Surface Enhanced Raman Scattering (SERS) Studies of Gold and Silver Nanoparticles Prepared by Laser Ablation

    PubMed Central

    Herrera, Gloria M.; Padilla, Amira C.; Hernandez-Rivera, Samuel P.

    2013-01-01

    Gold and silver nanoparticles (NPs) were prepared in water, acetonitrile and isopropanol by laser ablation methodologies. The average characteristic (longer) size of the NPs obtained ranged from 3 to 70 nm. 4-Aminobenzebethiol (4-ABT) was chosen as the surface enhanced Raman scattering (SERS) probe molecule to determine the optimum irradiation time and the pH of aqueous synthesis of the laser ablation-based synthesis of metallic NPs. The synthesized NPs were used to evaluate their capacity as substrates for developing more analytical applications based on SERS measurements. A highly energetic material, TNT, was used as the target compound in the SERS experiments. The Raman spectra were measured with a Raman microspectrometer. The results demonstrate that gold and silver NP substrates fabricated by the methods developed show promising results for SERS-based studies and could lead to the development of micro sensors.

  14. New SERS-active alumina-based sorbents containing Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Yurova, Nadezhda S.; Markina, Natalia E.; Galushka, Victor V.; Burashnikova, Marina M.; Zakharevich, Andrey M.; Markin, Alexey V.; Rusanova, Tatiana Y.

    2016-04-01

    New SERS-active materials were obtained by preparation of alumina with embedded silver nanoparticles and their application both as sorbents for pre-concentration and SERS platforms was studied. The influence of ionic strength on Ag NPs size, absorption spectra and SERS signal was investigated. Synthesized materials were examined by Raman spectroscopy, scanning electron microscopy, and UV-visible spectroscopy. The optimal conditions for SERSmeasurements were chosen. Synthesized materials were applied for pre-concentration of model analytes (Rhodamine 6G, folic acid and pyrene) and their SERS detection directly within the sorbent. It was shown that the recovery of analytes could be improved by alumina modification. The combination of surface-enhanced Raman spectroscopy with preconcentration is a promising instrument for analytical applications.

  15. Silver nanoparticles deposited inverse opal film as a highly active and uniform SERS substrate

    NASA Astrophysics Data System (ADS)

    Zhao, Junhong; Lin, Jian; Li, Xiuhua; Zhao, Guannan; Zhang, Wenjun

    2015-08-01

    Ag-decorated TiO2 inverse opal films (ATIO) with high surface-enhanced Raman scattering (SERS) enhancement were prepared using an electroless deposition process. The Ag nanoparticles (NPs) are well-dispersed and deposited on the edge of macroporous walls. The structure and optical properties of the sample ATIO have been characterized. The Ag-loading cycles and pore sizes of TiO2 inverse opal are the key factors determining the magnitude of SERS signal enhancement. The optimized ATIO samples exhibit high SERS signal enhancement ability and reproducibility. The enhancement factor about 104 and the detection limit of 10-10 M for R6G were achieved. The further application in detecting malachite green is demonstrated. A limit of detection approximately 10-9 M was achieved. The results show that the ATIO nanostructure is promising for using as sensor substrates in SERS applications.

  16. Detection of SERS active labelled DNA based on surface affinity to silver nanoparticles.

    PubMed

    Harper, Mhairi M; Dougan, Jennifer A; Shand, Neil C; Graham, Duncan; Faulds, Karen

    2012-05-07

    Developments in specific DNA detection assays have been shown to be increasingly beneficial for molecular diagnostics and biological research. Many approaches use optical spectroscopy as an assay detection method and, owing to the sensitivity and molecular specificity offered, surface enhanced Raman scattering (SERS) spectroscopy has become a competitively exploited technique. This study utilises SERS to demonstrate differences in affinity of dye labelled DNA through differences in electrostatic interactions with silver nanoparticles. Results show clear differences in the SERS intensity obtained from single stranded DNA, double stranded DNA and a free dye label and demonstrate surface attraction is driven through electrostatic charges on the nucleotides and not the SERS dye. It has been further demonstrated that, through optimisation of experimental conditions and careful consideration of sequence composition, a DNA detection method with increased sample discrimination at lower DNA concentrations can be achieved.

  17. Tuning the SERS Response with Ag-Au Nanoparticle-Embedded Polymer Thin Film Substrates.

    PubMed

    Rao, V Kesava; Radhakrishnan, T P

    2015-06-17

    Development of facile routes to the fabrication of thin film substrates with tunable surface enhanced Raman scattering (SERS) efficiency and identification of the optimal conditions for maximizing the enhancement factor (EF) are significant in terms of both fundamental and application aspects of SERS. In the present work, polymer thin films with embedded bimetallic nanoparticles of Ag-Au are fabricated by a simple two-stage protocol. Ag nanoparticles are formed in the first stage, by the in situ reduction of silver nitrate by the poly(vinyl alcohol) (PVA) film through mild thermal annealing, without any additional reducing agent. In the second stage, aqueous solutions of chloroauric acid spread on the Ag-PVA thin film under ambient conditions, lead to the galvanic displacement of Ag by Au in situ inside the film, and the formation of Ag-Au particles. Evolution of the morphology of the bimetallic nanoparticles into hollow cage structures and the distribution of Au on the nanoparticles are revealed through electron microscopy and energy dispersive X-ray spectroscopy. The localized surface plasmon resonance (LSPR) extinction of the nanocomposite thin film evolves with the Ag-Au composition; theoretical simulation of the extinction spectra provides insight into the observed trends. The Ag-Au-PVA thin films are found to be efficient substrates for SERS. The EF follows the variation of the LSPR extinction vis-à-vis the excitation laser wavelength, but with an offset, and the maximum SERS effect is obtained at very low Au content; experiments with Rhodamine 6G showed EFs on the order of 10(8) and a limit of detection of 0.6 pmol. The present study describes a facile and simple fabrication of a nanocomposite thin film that can be conveniently deployed in SERS investigations, and the utility of the bimetallic system to tune and maximize the EF.

  18. SERS Detection of Biomolecules by Highly Sensitive and Reproducible Raman-Enhancing Nanoparticle Array

    NASA Astrophysics Data System (ADS)

    Chan, Tzu-Yi; Liu, Ting-Yu; Wang, Kuan-Syun; Tsai, Kun-Tong; Chen, Zhi-Xin; Chang, Yu-Chi; Tseng, Yi-Qun; Wang, Chih-Hao; Wang, Juen-Kai; Wang, Yuh-Lin

    2017-05-01

    This paper describes the preparation of nanoarrays composed of silver nanoparticles (AgNPs: 20-50 nm) for use as surface-enhanced Raman scattering (SERS) substrates. The AgNPs were grown on porous anodic aluminum oxide (AAO) templates by electrochemical plating, and the inter-channel gap of AAO channels is between 10 and 20 nm. The size and interparticle gap of silver particles were adjusted in order to achieve optimal SERS signals and characterized by scanning electron microscopy, atomic force microscopy, and Raman spectroscopy. The fluctuation of SERS intensity is about 10-20% when measuring adenine solutions, showing a great reproducible SERS sensing. The nanoparticle arrays offer a large potential for practical applications as shown by the SERS-based quantitative detection and differentiation of adenine (A), thymine (T), cytosine (C), guanine (G), β-carotene, and malachite green. The respective detection limits are <1 ppb for adenine and <0.63 ppm for β-carotene and malachite green, respectively.

  19. Optimization of Nanoparticle-Based SERS Substrates through Large-Scale Realistic Simulations

    PubMed Central

    2016-01-01

    Surface-enhanced Raman scattering (SERS) has become a widely used spectroscopic technique for chemical identification, providing unbeaten sensitivity down to the single-molecule level. The amplification of the optical near field produced by collective electron excitations —plasmons— in nanostructured metal surfaces gives rise to a dramatic increase by many orders of magnitude in the Raman scattering intensities from neighboring molecules. This effect strongly depends on the detailed geometry and composition of the plasmon-supporting metallic structures. However, the search for optimized SERS substrates has largely relied on empirical data, due in part to the complexity of the structures, whose simulation becomes prohibitively demanding. In this work, we use state-of-the-art electromagnetic computation techniques to produce predictive simulations for a wide range of nanoparticle-based SERS substrates, including realistic configurations consisting of random arrangements of hundreds of nanoparticles with various morphologies. This allows us to derive rules of thumb for the influence of particle anisotropy and substrate coverage on the obtained SERS enhancement and optimum spectral ranges of operation. Our results provide a solid background to understand and design optimized SERS substrates. PMID:28239616

  20. Trace determination of thiram using SERS-active hollow sea-urchin gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Guanghui; Zhang, Chuankun; Ma, Yanan; Wang, Zheng; Wang, Shun; Xu, Chan; Wang, Dashuang

    2017-04-01

    Surface-enhanced Raman scattering (SERS) is greatly structure-dependent on the absorbed nanoparticles. Nanostructures with different novel morphologies show different Raman enhancement factor orders of magnitude. Herein, a unique nanostructure with fruitful SERS-active sites, composed of hollow interiors and thorns which named as hollow sea-urchin gold nanoparticles (HSU-GNPs), was synthesized by using a one-pot galvanic replacement method. And the corresponding morphologies and optical properties were characterized by TEM images and absorption spectra. Importantly, the synthetic parameters of HSU-GNPs were optimized to obtain a superior SERS performance by analyzing the formation mechanism and the SERS spectra of R6G-labeled HSU-GNPs which obtained at different concentrations of AgNO3. Furthermore, the SERS-based application of HSU-GNPs was performed on the dose-response detection of thiram. The experimental result shows this detection strategy is available for thiram with decent sensitivity and reproducibility, which suggests that it is an excellent candidate for the detection of pesticides.

  1. Optimization of Nanoparticle-Based SERS Substrates through Large-Scale Realistic Simulations.

    PubMed

    Solís, Diego M; Taboada, José M; Obelleiro, Fernando; Liz-Marzán, Luis M; García de Abajo, F Javier

    2017-02-15

    Surface-enhanced Raman scattering (SERS) has become a widely used spectroscopic technique for chemical identification, providing unbeaten sensitivity down to the single-molecule level. The amplification of the optical near field produced by collective electron excitations -plasmons- in nanostructured metal surfaces gives rise to a dramatic increase by many orders of magnitude in the Raman scattering intensities from neighboring molecules. This effect strongly depends on the detailed geometry and composition of the plasmon-supporting metallic structures. However, the search for optimized SERS substrates has largely relied on empirical data, due in part to the complexity of the structures, whose simulation becomes prohibitively demanding. In this work, we use state-of-the-art electromagnetic computation techniques to produce predictive simulations for a wide range of nanoparticle-based SERS substrates, including realistic configurations consisting of random arrangements of hundreds of nanoparticles with various morphologies. This allows us to derive rules of thumb for the influence of particle anisotropy and substrate coverage on the obtained SERS enhancement and optimum spectral ranges of operation. Our results provide a solid background to understand and design optimized SERS substrates.

  2. Effect of toxicity of Ag nanoparticles on SERS spectral variance of bacteria

    NASA Astrophysics Data System (ADS)

    Cui, Li; Chen, Shaode; Zhang, Kaisong

    2015-02-01

    Ag nanoparticles (NPs) have been extensively utilized in surface-enhanced Raman scattering (SERS) spectroscopy for bacterial identification. However, Ag NPs are toxic to bacteria. Whether such toxicity can affect SERS features of bacteria and interfere with bacterial identification is still unknown and needed to explore. Here, by carrying out a comparative study on non-toxic Au NPs with that on toxic Ag NPs, we investigated the influence of nanoparticle concentration and incubation time on bacterial SERS spectral variance, both of which were demonstrated to be closely related to the toxicity of Ag NPs. Sensitive spectral alterations were observed on Ag NPs with increase of NPs concentration or incubation time, accompanied with an obvious decrease in number of viable bacteria. In contrast, SERS spectra and viable bacterial number on Au NPs were rather constant under the same conditions. A further analysis on spectral changes demonstrated that it was cell response (i.e. metabolic activity or death) to the toxicity of Ag NPs causing spectral variance. However, biochemical responses to the toxicity of Ag were very different in different bacteria, indicating the complex toxic mechanism of Ag NPs. Ag NPs are toxic to a great variety of organisms, including bacteria, fungi, algae, protozoa etc., therefore, this work will be helpful in guiding the future application of SERS technique in various complex biological systems.

  3. Synthesis of Janus plasmonic–magnetic, star–sphere nanoparticles, and their application in SERS detection

    PubMed Central

    Jiménez de Aberasturi, Dorleta; Winckelmans, Naomi; Langer, Judith; Bals, Sara; Liz-Marzán, Luis M.

    2016-01-01

    Multicomponent nanoparticles are of particular interest due to a unique combination of properties at the nanoscale, which make them suitable for a wide variety of applications. Among them, Janus nanoparticles, presenting two distinct surface regions, can lead to specific interactions with interfaces, biomolecules, membranes etc. We report the synthesis of Janus nanoparticles comprising iron oxide nanospheres and gold nanostars, through two consecutive seed-mediated-growth steps. Electron tomography combining HAADF-STEM and EDX mapping has been performed to evaluate the spatial distribution of the two components of the nanoparticle, showing their clear separation in a Janus morphology. Additionally, SERS measurements assisted by magnetic separation were carried out to assess the application of combined plasmonic and magnetic properties for sensing. PMID:27419362

  4. Room Temperature Synthesis of Highly Monodisperse and Sers-Active Glucose-Reduced Gold Nanoparticles

    NASA Astrophysics Data System (ADS)

    Boitor, R. A.; Tódor, I. Sz.; Leopold, L. F.; Leopold, N.

    2015-07-01

    A novel method of synthesizing gold nanoparticles was developed through which glucose-coated nanospheres of high monodispersity were synthesized at room temperature. More than 85% of the nanoparticles showed a mean diameter of 8-9 nm. The nanoparticles were characterized through TEM, UV-Vis absorption spectroscopy, dynamic light scattering (DLS), and Zeta potential measurements and were found to be highly stable in colloidal form over time with a surface potential of -38.7 mV. The nanoparticles also showed a great Raman enhancing factor when they were tested as a surface-enhanced Raman scattering (SERS) substrate on various analytes such as rhodamine 6G, crystal violet chloride, cresyl violet chloride, rose bengal, and the Cu(II) 4-(2-pyridylazo)resorcinol complex at micromolar concentrations.

  5. Dynamic SERS imaging of cellular transport pathways with endocytosed gold nanoparticles.

    PubMed

    Ando, Jun; Fujita, Katsumasa; Smith, Nicholas I; Kawata, Satoshi

    2011-12-14

    Dynamic SERS imaging inside a living cell is demonstrated with the use of a gold nanoparticle, which travels through the intracellular space to probe local molecular information over time. Simultaneous tracking of particle motion and SERS spectroscopy allows us to detect intracellular molecules at 65 nm spatial resolution and 50 ms temporal resolution, providing molecular maps of organelle transport and lisosomal accumulation. Multiplex spectral and trajectory imaging will enable imaging of specific dynamic biological functions such as membrane protein diffusion, nuclear entry, and rearrangement of cellular cytoskeleton.

  6. Gold nanoparticles decorated liposomes and their SERS performance in tumor cells

    NASA Astrophysics Data System (ADS)

    Zhu, D.; Wang, Z. Y.; Zong, S. F.; Chen, H.; Chen, P.; Li, M. Y.; Wu, L.; Cui, Y. P.

    2015-05-01

    Due to their unique properties, liposomes have been widely used as drug nanocarriers. Herein a liposome-Au nanohybrid has been demonstrated as a SERS active intracellular drug nanocarrier. In this study, cationic Raman reporter tagged gold nanoparticles (Au@4MBA@PAH) were anchored onto the surfaces of anionic liposomes via electrostatic interactions. Using SKBR3 cells as model cells, we revealed that the hybrid formulation can be effectively taken up by tumor cells and tracked by the SERS signals. Collectively, the liposome-Au nanohybrids hold great promise in biomedical applications.

  7. SERS efficiencies of micrometric polystyrene beads coated with gold and silver nanoparticles: the effect of nanoparticle size

    NASA Astrophysics Data System (ADS)

    Mir-Simon, Bernat; Morla-Folch, Judit; Gisbert-Quilis, Patricia; Pazos-Perez, Nicolas; Xie, Hai-nan; Bastús, Neus G.; Puntes, Víctor; Alvarez-Puebla, Ramon A.; Guerrini, Luca

    2015-11-01

    Rapid advances in nanofabrication techniques of reproducibly manufacturing plasmonic substrates with well-defined nanometric scale features and very large electromagnetic enhancements paved the way for the final translation of the analytical potential of surface-enhanced Raman scattering (SERS) to real applications. A vast number of different SERS substrates have been reported in the literature. Among others, discrete particles consisting of an inorganic micrometric or sub-micrometric core homogeneously coated with plasmonic nanoparticles stand out for their ease of fabrication, excellent SERS enhancing properties, long-term optical stability and remarkable experimental flexibility (manipulation, storage etc). In this article, we performed a systematic experimental study of the correlation between the size of quasi-spherical gold and silver nanoparticle and the final optical property of their corresponding assembles onto micrometric polystyrene (PS) beads. The size and composition of nanoparticles play a key role in tuning the SERS efficiency of the hybrid material at a given excitation wavelength. This study provides valuable information for the selection and optimization of the appropriate PS@NPs substrates for the desired applications.

  8. Organic/inorganic hybrid coatings for anticorrosion

    NASA Astrophysics Data System (ADS)

    He, Zhouying

    Compared to organic coatings, organic-inorganic hybrid coatings can potentially improve the anticorrosion performance. The organic phase provides the excellent mechaincal and barrier properties while the inorganic phase acts as an adhesion promoter and corrosion inhibitor. Despite that many studies on alkoxylsilane-based hybrid coatings have been developed and studied, their weatherability and anticorrosion performance has been rarely evaluated. On the other hand, organic-inorganic hybrid coatings based on mixed sol-gel precursors have received much less attention compared to alkoxylsilane-based hybrid coatings. In the first part, polyurethane hybrid coatings with a unique hybrid crosslinked structure as an improved unicoat were successfully prepared. The effect of polyesters on physical properties of the hybrid coatings was studied. Polyurethane coatings derived from cycloaliphatic polyester show comparable properties than those derived from the commercially viable aromatic polyester. Introducing the polysiloxane part into the polyurethane coatings enhanced the crosslinking density, Tg, mechanical properties, and general coating properties. The increased adhesion between the hybrid coating and the substrate make the hybrid coating a good candidate for anticorrosion application, which is shown by electrochemical impedance spectroscopy (EIS). The degradation mechanism of the polyurethane/polysiloxane hybrid coatings under various weathering conditions was shown to be the scission of the urethane and ester groups in the organic phase along with reorganizing and rearranging of the inorganic phase. The anticorrosion performance of the cycloaliphatic hybrid was much better than that of aromatic based hybrid under outdoor weathering based on visual observation and EIS analysis. Acid undercutting is an issue for TEOS based hybrid coating. In the second part, design of experiments (DOEs) was used to statistically investigate on the effect of sol-gel precursors. The

  9. Naturally inspired SERS substrates fabricated by photocatalytically depositing silver nanoparticles on cicada wings.

    PubMed

    Tanahashi, Ichiro; Harada, Yoshiyuki

    2014-01-01

    Densely stacked Ag nanoparticles with an average diameter of 199 nm were effectively deposited on TiO2-coated cicada wings (Ag/TiO2-coated wings) from a water-ethanol solution of AgNO3 using ultraviolet light irradiation at room temperature. It was seen that the surfaces of bare cicada wings contained nanopillar array structures. In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm. Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar(+) laser. The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates.

  10. Naturally inspired SERS substrates fabricated by photocatalytically depositing silver nanoparticles on cicada wings

    PubMed Central

    2014-01-01

    Densely stacked Ag nanoparticles with an average diameter of 199 nm were effectively deposited on TiO2-coated cicada wings (Ag/TiO2-coated wings) from a water-ethanol solution of AgNO3 using ultraviolet light irradiation at room temperature. It was seen that the surfaces of bare cicada wings contained nanopillar array structures. In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm. Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar+ laser. The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates. PMID:24959110

  11. Poly(ethylene glycol)-stabilized silver nanoparticles for bioanalytical applications of SERS spectroscopy.

    PubMed

    Shkilnyy, Andriy; Soucé, Martin; Dubois, Pierre; Warmont, Fabienne; Saboungi, Marie-Louise; Chourpa, Igor

    2009-09-01

    The present work depicts the efficient one-step synthesis and detailed evaluation of stable aqueous colloids of silver nanoparticles (NPs) coated with poly(ethylene glycol) (PEG) covalently attached to their surface. Due to steric repulsion between polymer-modified surfaces, the stability of the nanoparticle suspension was preserved even at high ionic strength (0.1 M NaCl). At the same time, the PEG coating remains sufficiently permeable to allow surface-enhanced Raman scattering (SERS) from micromolar concentrations of small molecules such as the anticancer drug mitoxantrone (MTX). The enhancement efficiency of the hot spot-free Ag-PEG was compared to that of citrate-stabilized Ag colloids used after pre-aggregation. The potential of the polymer-stabilized colloids developed in this study is discussed in terms of bioanalytical applications of SERS spectroscopy.

  12. Bifunctional nanoparticles for SERS monitoring and magnetic intervention of assembly and enzyme cutting of DNAs

    SciTech Connect

    Lin, Liqin; Crew, Elizabeth; Yan, Hong; Shan, Shiyao; Skeete, Zakiya; Mott, Derrick; Krentsel, Tatiana; Yin, Jun; Chernova, Natasha A.; Luo, Jin; Engelhard, Mark H.; Wang, Chong M.; Li, Qingbiao; Zhong, Chuan-Jian

    2013-07-27

    The ability to detect and intervene in DNA assembly, disassembly, and enzyme cutting processes in a solution phase requires effective signal transduction and stimulus response. This report demonstrates a novel bifunctional strategy for the creation of this ability using gold- and silver-coated MnZn ferrite nanoparticles (MZF@Au or MZF@Ag) that impart magnetic and surfaceenhanced Raman scattering (SERS) functionalities to these processes. The double-stranded DNA linkage of labeled gold nanoparticles with MZF@Au (or MZF@Ag) produces interparticle "hot-spots" for real-time SERS monitoring of the DNA assembly, disassembly, or enzyme cutting processes, during which the magnetic component provides an effective means for intervention in the solution. The unique combination of the nanoprobes functionalities serves a new paradigm for the design of functional nanoprobes in biomolecular recognition and intervention.

  13. Naturally inspired SERS substrates fabricated by photocatalytically depositing silver nanoparticles on cicada wings

    NASA Astrophysics Data System (ADS)

    Tanahashi, Ichiro; Harada, Yoshiyuki

    2014-06-01

    Densely stacked Ag nanoparticles with an average diameter of 199 nm were effectively deposited on TiO2-coated cicada wings (Ag/TiO2-coated wings) from a water-ethanol solution of AgNO3 using ultraviolet light irradiation at room temperature. It was seen that the surfaces of bare cicada wings contained nanopillar array structures. In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm. Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar+ laser. The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates.

  14. Heparin Assisted Photochemical Synthesis of Gold Nanoparticles and Their Performance as SERS Substrates

    PubMed Central

    Rodríguez-Torres, Maria del Pilar; Díaz-Torres, Luis Armando; Romero-Servin, Sergio

    2014-01-01

    Reactive and pharmaceutical-grade heparins were used as biologically compatible reducing and stabilizing agents to photochemically synthesize colloidal gold nanoparticles. Aggregates and anisotropic shapes were obtained photochemically under UV black-light lamp irradiation (λ = 366 nm). Heparin-functionalized gold nanoparticles were characterized by Scanning Electron Microscopy and UV-Vis spectroscopy. The negatively charged colloids were used for the Surface Enhanced Raman Spectroscopy (SERS) analysis of differently charged analytes (dyes). Measurements of pH were taken to inspect how the acidity of the medium affects the colloid-analyte interaction. SERS spectra were taken by mixing the dyes and the colloidal solutions without further functionalization or addition of any aggregating agent. PMID:25342319

  15. Heparin assisted photochemical synthesis of gold nanoparticles and their performance as SERS substrates.

    PubMed

    Rodríguez-Torres, Maria del Pilar; Díaz-Torres, Luis Armando; Romero-Servin, Sergio

    2014-10-23

    Reactive and pharmaceutical-grade heparins were used as biologically compatible reducing and stabilizing agents to photochemically synthesize colloidal gold nanoparticles. Aggregates and anisotropic shapes were obtained photochemically under UV black-light lamp irradiation (λ = 366 nm). Heparin-functionalized gold nanoparticles were characterized by Scanning Electron Microscopy and UV-Vis spectroscopy. The negatively charged colloids were used for the Surface Enhanced Raman Spectroscopy (SERS) analysis of differently charged analytes (dyes). Measurements of pH were taken to inspect how the acidity of the medium affects the colloid-analyte interaction. SERS spectra were taken by mixing the dyes and the colloidal solutions without further functionalization or addition of any aggregating agent.

  16. Magnetically Assembled SERS Substrates Composed of Iron-Silver Nanoparticles Obtained by Laser Ablation in Liquid.

    PubMed

    Scaramuzza, Stefano; Badocco, Denis; Pastore, Paolo; Coral, Diego F; Fernández van Raap, Marcela B; Amendola, Vincenzo

    2017-05-05

    The widespread application of surface-enhanced Raman scattering (SERS) would benefit from simple and scalable self-assembly procedures for the realization of plasmonic arrays with a high density of electromagnetic hot-spots. To this aim, the exploitation of iron-doped silver nanoparticles (NPs) synthesized by laser ablation of a bulk bimetallic iron-silver target immersed in ethanol is described. The use of laser ablation in liquid is key to achieving bimetallic NPs in one step with a clean surface available for functionalization with the desired thiolated molecules. These iron-silver NPs show SERS performances, a ready response to external magnetic fields and complete flexibility in surface coating. All these characteristics were used for the magnetic assembly of plasmonic arrays which served as SERS substrates for the identification of molecules of analytical interest. The magnetic assembly of NPs allowed a 28-fold increase in the SERS signal of analytes compared to not-assembled NPs. The versatility of substrate preparation and the SERS performances were investigated as a function of NPs surface coating among different thiolated ligands. These results show a simple procedure to obtain magnetically assembled regenerable plasmonic arrays for repeated SERS investigation of different samples, and it can be of inspiration for the realization of other self-assembled and reconfigurable magnetic-plasmonic devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. A hybrid organic-inorganic perovskite dataset

    NASA Astrophysics Data System (ADS)

    Kim, Chiho; Huan, Tran Doan; Krishnan, Sridevi; Ramprasad, Rampi

    2017-05-01

    Hybrid organic-inorganic perovskites (HOIPs) have been attracting a great deal of attention due to their versatility of electronic properties and fabrication methods. We prepare a dataset of 1,346 HOIPs, which features 16 organic cations, 3 group-IV cations and 4 halide anions. Using a combination of an atomic structure search method and density functional theory calculations, the optimized structures, the bandgap, the dielectric constant, and the relative energies of the HOIPs are uniformly prepared and validated by comparing with relevant experimental and/or theoretical data. We make the dataset available at Dryad Digital Repository, NoMaD Repository, and Khazana Repository (http://khazana.uconn.edu/), hoping that it could be useful for future data-mining efforts that can explore possible structure-property relationships and phenomenological models. Progressive extension of the dataset is expected as new organic cations become appropriate within the HOIP framework, and as additional properties are calculated for the new compounds found.

  18. Hybrid Organic-Inorganic Perovskite Photodetectors.

    PubMed

    Tian, Wei; Zhou, Huanping; Li, Liang

    2017-09-12

    Hybrid organic-inorganic perovskite materials garner enormous attention for a wide range of optoelectronic devices. Due to their attractive optical and electrical properties including high optical absorption coefficient, high carrier mobility, and long carrier diffusion length, perovskites have opened up a great opportunity for high performance photodetectors. This review aims to give a comprehensive summary of the significant results on perovskite-based photodetectors, focusing on the relationship among the perovskite structures, device configurations, and photodetecting performances. An introduction of recent progress in various perovskite structure-based photodetectors is provided. The emphasis is placed on the correlation between the perovskite structure and the device performance. Next, recent developments of bandgap-tunable perovskite and hybrid photodetectors built from perovskite heterostructures are highlighted. Then, effective approaches to enhance the stability of perovskite photodetector are presented, followed by the introduction of flexible and self-powered perovskite photodetectors. Finally, a summary of the previous results is given, and the major challenges that need to be addressed in the future are outlined. A comprehensive summary of the research status on perovskite photodetectors is hoped to push forward the development of this field. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Hybrid organic-inorganic polariton laser.

    PubMed

    Paschos, G G; Somaschi, N; Tsintzos, S I; Coles, D; Bricks, J L; Hatzopoulos, Z; Lidzey, D G; Lagoudakis, P G; Savvidis, P G

    2017-09-12

    Organic materials exhibit exceptional room temperature light emitting characteristics and enormous exciton oscillator strength, however, their low charge carrier mobility prevent their use in high-performance applications such as electrically pumped lasers. In this context, ultralow threshold polariton lasers, whose operation relies on Bose-Einstein condensation of polaritons - part-light part-matter quasiparticles, are highly advantageous since the requirement for high carrier injection no longer holds. Polariton lasers have been successfully implemented using inorganic materials owing to their excellent electrical properties, however, in most cases their relatively small exciton binding energies limit their operation temperature. It has been suggested that combining organic and inorganic semiconductors in a hybrid microcavity, exploiting resonant interactions between these materials would permit to dramatically enhance optical nonlinearities and operation temperature. Here, we obtain cavity mediated hybridization of GaAs and J-aggregate excitons in the strong coupling regime under electrical injection of carriers as well as polariton lasing up to 200 K under non-resonant optical pumping. Our demonstration paves the way towards realization of hybrid organic-inorganic microcavities which utilise the organic component for sustaining high temperature polariton condensation and efficient electrical injection through inorganic structure.

  20. Surface modified gold nanoparticles for SERS based detection of vulnerable plaque formations (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Matthäus, Christian; Dugandžić, Vera; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

    2017-02-01

    Cardiovascular diseases are the leading cause of death worldwide. Atherosclerosis is closely related to the majority of these diseases, as a process of thickening and stiffening of the arterial walls through accumulation of lipids, which is a consequence of aging and life style. Atherosclerosis affects all people in some extent, but not all arterial plaques will necessarily lead to the complications, such as thrombosis, stroke and heart attack. One of the greatest challenges in the risk assessment of atherosclerotic depositions is the detection and recognition of plaques which are unstable and prone to rupture. These vulnerable plaques usually consist of a lipid core that attracts macrophages, a type of white blood cells that are responsible for the degradation of lipids. It has been hypothesized that the amount of macrophages relates to the overall plaque stability. As phagocytes, macrophages also act as recipients for nanoscale particles or structures. Administered gold nanoparticles are usually rabidly taken up by macrophages residing within arterial walls and can therefore be indirectly detected. A very sensitive strategy for probing gold nanoparticles is by utilizing surface enhanced Raman scattering (SERS). By modifying the surface of these particles with SERS active labels it is possible to generate highly specific signals that exhibit sensitivity comparable to fluorescence. SERS labeled gold nanoparticles have been synthesized and the uptake dynamics and efficiency on macrophages in cell cultures was investigated using Raman microscopic imaging. The results clearly show that nanoparticles are taken up by macrophages and support the potential of SERS spectroscopy for the detection of vulnerable plaques. Acknowledgements: Financial support from the Carl Zeiss Foundation is highly acknowledged. The project "Jenaer Biochip Initiative 2.0" (03IPT513Y) within the framework "InnoProfile Transfer - Unternehmen Region" is supported by the Federal Ministry of

  1. Gold nanoparticles-decorated single silver nanowire as an efficient SERS-active substrate

    NASA Astrophysics Data System (ADS)

    Tan, En-zhong

    2014-07-01

    A novel surface-enhanced Raman scattering (SERS)-active substrate based on Au nanoparticles (AuNPs)-coated silver nanowire (AgNW) is obtained by an effective and simple method. The results show that the hybrid structures prepared by this method are powerful SERS-active substrates for the detection of malachite green (MG) molecules with the limit of 1 nmol/L. The excellent enhancing ability mainly comes from two kinds of hot spots. One is from the gaps among the adjacent AuNPs, and the other is the presence of zone between AuNPs and AgNW. In particular, the AuNPs-coated AgNW can be viewed through the objective of the confocal Raman spectrometer due to the length of the AgNW reaches microns, which can improve the repeatability of detection. Moreover, it is of great significance in research of SERS mechanism and application.

  2. Self-assembly of gold nanoparticles to silver microspheres as highly efficient 3D SERS substrates

    PubMed Central

    2013-01-01

    Herein we report a simple, one-pot, surfactant-free synthesis of 3D Ag microspheres (AgMSs) in aqueous phase at room temperature. The 3D AgMSs act as supports to fix the gold nanoparticles (GNPs) in 3D space via the interaction between the carboxyl groups of GNPs and the Ag atoms of AgMSs. The ensemble of AgMSs@GNPs with high surface-enhanced Raman scattering (SERS) activity and sensitivity can be an ideal 3D substrate choice for practical SERS detection applications. The simple self-assembly strategy may be extended to other metallic materials with great potentials in SERS, catalysis, and photoelectronic devices. PMID:23587323

  3. [Size dependent SERS activity of gold nanoparticles studied by 3D-FDTD simulation].

    PubMed

    Li, Li-mei; Fang, Ping-ping; Yang, Zhi-lin; Huang, Wen-da; Wu, De-yin; Ren, Bin; Tian, Zhong-qun

    2009-05-01

    By synthesizing Au nanoparticles with the controllable size from about 16 to 160 nm and measuring their SERS activity, the authors found that Au nanoparticles film with a size in the range of 120-135 nm showed the highest SERS activity with the 632.8 nm excitation, which is different from previous experimental results and theoretical predictions. The three dimensional finite difference time domain (3D-FDTD)method was employed to simulate the size dependent SERS activity. At the 632.8 nm excitation, the particles with a size of 110 nm shows the highest enhancement under coupling condition and presents an enhancement as high as 10(9) at the hot site. If the enhancement is averaged over the whole surface, the enhancement can still be as high as 10(7), in good agreement with our experimental data. For Au nanoparticles with a larger size such as 220 nm, the multipolar effect leads to the appearance of the second maximum enhancement with the increase in particles size. The averaged enhancement for the excitation line of 325 nm is only 10(2).

  4. Ultrasensitive SERS performance in 3D "sunflower-like" nanoarrays decorated with Ag nanoparticles.

    PubMed

    Zhang, Xiaolei; Xiao, Xiangheng; Dai, Zhigao; Wu, Wei; Zhang, Xingang; Fu, Lei; Jiang, Changzhong

    2017-03-02

    Low-cost, stabilized and ultrasensitive three-dimensional (3D) hierarchical surface-enhanced Raman scattering substrates ("sunflower-like" nanoarrays decorated with Ag nanoparticles, denoted as SLNAs-Ag) have been obtained by fabricating binary colloidal crystals and then decorating with Ag nanoparticles. In order to provide a larger density of hot spots within the laser-illumination area, the silica sphere arrays were chosen as the island-type platform for the polystyrene (PS) nanosphere deposition, and the distances between the PS nanospheres were tuned by etching for different durations. Compared with conventional 2D planar systems, the as-fabricated 3D SLNAs-Ag exhibited extremely high SERS sensitivity ascribed to the larger SERS active regions. Quantitative detection of molecules with an extremely low incident laser power was achieved on the "sunflower-like" nanoarrays in which the PS nanospheres were etched for 5 minutes and decorated with Ag nanoparticles, and the corresponding analytical enhancement factor is calculated to be 2 × 10(14) with the concentration of rhodamine 6G down to 10(-15) M. Based on the achieved SERS substrates, we have further demonstrated the highly sensitive detection of molecules such as melamine for food safety inspection.

  5. Chemiresistive/SERS dual sensor based on densely packed gold nanoparticles.

    PubMed

    Boca, Sanda; Leordean, Cosmin; Astilean, Simion; Farcau, Cosmin

    2015-01-01

    Chemiresistors are a class of sensitive electrical devices capable of detecting (bio)chemicals by simply monitoring electrical resistance. Sensing based on surface enhanced Raman scattering (SERS) represents a radically different approach, in which molecules are optically detected according to their vibrational spectroscopic fingerprint. Despite different concepts are involved, one can find in the literature examples from both categories reporting sensors made of gold nanoparticles. The same building blocks appear because both sensor classes share a common principle: nanometric interparticle gaps are needed, for electron tunneling in chemiresistors, and for enhancing electromagnetic fields by plasmon coupling in SERS-based sensors. By exploiting such nano-gaps in self-assembled films of gold nanoparticles, we demonstrate the proof of concept of a dual electrical/optical sensor, with both chemiresistive and SERS capabilities. The proposed device is realized by self-assembling 15 nm gold nanoparticles into few micrometers-wide strips across commercially available interdigitated electrodes. The dual-mode operation of the device is demonstrated by the detection of a biologically relevant model analyte, 4-mercaptophenyl boronic acid.

  6. Highly-Sensitive Surface-Enhanced Raman Spectroscopy (SERS)-based Chemical Sensor using 3D Graphene Foam Decorated with Silver Nanoparticles as SERS substrate

    PubMed Central

    Srichan, Chavis; Ekpanyapong, Mongkol; Horprathum, Mati; Eiamchai, Pitak; Nuntawong, Noppadon; Phokharatkul, Ditsayut; Danvirutai, Pobporn; Bohez, Erik; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2016-01-01

    In this work, a novel platform for surface-enhanced Raman spectroscopy (SERS)-based chemical sensors utilizing three-dimensional microporous graphene foam (GF) decorated with silver nanoparticles (AgNPs) is developed and applied for methylene blue (MB) detection. The results demonstrate that silver nanoparticles significantly enhance cascaded amplification of SERS effect on multilayer graphene foam (GF). The enhancement factor of AgNPs/GF sensor is found to be four orders of magnitude larger than that of AgNPs/Si substrate. In addition, the sensitivity of the sensor could be tuned by controlling the size of silver nanoparticles. The highest SERS enhancement factor of ∼5 × 104 is achieved at the optimal nanoparticle size of 50 nm. Moreover, the sensor is capable of detecting MB over broad concentration ranges from 1 nM to 100 μM. Therefore, AgNPs/GF is a highly promising SERS substrate for detection of chemical substances with ultra-low concentrations. PMID:27020705

  7. SERS of semiconducting nanoparticles (TiO{sub 2} hybrid composites).

    SciTech Connect

    Musumeci, A.; Gosztola, D.; Schiller, T.; Dimitrijevic, N.; Mujica, V.; Martin, D.; Rajh, T.

    2009-04-13

    Raman scattering of molecules adsorbed on the surface of TiO{sub 2} nanoparticles was investigated. We find strong enhancement of Raman scattering in hybrid composites that exhibit charge transfer absorption with TiO{sub 2} nanoparticles. An enhancement factor up to {approx}10{sup 3} was observed in the solutions containing TiO{sub 2} nanoparticles and biomolecules, including the important class of neurotransmitters such as dopamine and dopac (3,4-dihydroxy-phenylacetic acid). Only selected vibrations are enhanced, indicating molecular specificity due to distinct binding and orientation of the biomolecules coupled to the TiO{sub 2} surface. All enhanced modes are associated with the asymmetric vibrations of attached molecules that lower the symmetry of the charge transfer complex. The intensity and the energy of selected vibrations are dependent on the size and shape of nanoparticle support. Moreover, we show that localization of the charge in quantized nanoparticles (2 nm), demonstrated as the blue shift of particle absorption, diminishes SERS enhancement. Importantly, the smallest concentration of adsorbed molecules shows the largest Raman enhancements suggesting the possibility for high sensitivity of this system in the detection of biomolecules that form a charge transfer complex with metal oxide nanoparticles. The wavelength-dependent properties of a hybrid composite suggest a Raman resonant state. Adsorbed molecules that do not show a charge transfer complex show weak enhancements probably due to the dielectric cavity effect.

  8. A SERS and electrical sensor from gas-phase generated Ag nanoparticles self-assembled on planar substrates.

    PubMed

    Wang, S; Tay, L-L; Liu, H

    2016-03-07

    Optical excitation of coupled plasmonic nanoparticles supports intense localized electromagnetic "hot-spots" which enable a variety of surface enhanced spectroscopies with the best known example being surface enhanced Raman scattering (SERS), currently of great interest for sensing applications. In this study, we present a novel SERS and electrical dual transduction chemical sensor based on gas-phase generated, negatively charged, silver nanoparticles self-assembled on glass slide forming a close-packed plasmonic monolayer thin-film that supports both SERS and electrical sensing. We demonstrate broad tunability of the localized surface plasmon resonance (LSPR) of the close-packed plasmonic nanoparticle monolayer thin-film sensors through control of the nanoparticle (NP) deposition time which directly influences the plasmonic coupling between neghibouring NPs. This broad tunability supports strong SERS activity from visible to near infrared (NIR) excitation wavelengths. We performed SERS and electrical measurements of a non-resonant molecule 4-mercaptobenzonitrile (4-MBN) as a sample Raman reporter molecule to determine the SERS enhancement factor of our SERS substrate. We measured an average SERS enhancement factor of 10(7) from our close-packed plasmonic nanoparticle monolayer thin-film sensor. Films which were grown below or above one nanoparticle monolayer both exhibited significantly lower SERS performance in one or more of SERS enhancement factor (EF), uniformity or repeatability. Our close-packed plasmonic nanoparticle monolayer thin-film sensors are highly uniform from point-to-point across the entire substrate and showed good reproducibility from batch-to-batch. These qualities are highly desirable for quantifiable detection of chemical and biological molecules. As an example application, this type of substrates provides an affordable and reliable sensing and identification capability for combatting new and emerging chemical and biological threats in

  9. SERS investigation of ciprofloxacin drug molecules on TiO2 nanoparticles.

    PubMed

    Yang, Libin; Qin, Xiaoyu; Jiang, Xin; Gong, Mengdi; Yin, Di; Zhang, Yingjiu; Zhao, Bing

    2015-07-21

    In this paper, TiO2 nanoparticles (NPs) with different crystallinity served as SERS-active substrates for SERS detection of ciprofloxacin (CIP) drug molecules for the first time. CIP is close to the surface of the TiO2 substrate through the carboxyl group. The mutual SERS enhancement behaviors between CIP molecules and TiO2 NPs were discovered, which are attributed to the contribution of the TiO2-to-molecule charge-transfer mechanism. The crystallinity of TiO2 NPs, the pH value of adsorption solution and the adsorption time have significant influences on the interaction and the SERS behavior between CIP and TiO2. When the calcination temperature of TiO2 NPs is 450 °C, the pH value of adsorption solution is 6 and the adsorption time is 9 h, the CIP molecules on TiO2 NPs exhibit the largest SERS enhancement.

  10. Use of Polycrystalline Ice for Assembly of Large Area Au Nanoparticle Superstructures as SERS Substrates.

    PubMed

    Bekana, Deribachew; Liu, Rui; Amde, Meseret; Liu, Jing-Fu

    2017-01-11

    It is still a great challenge to develop simple and low-cost methods for preparation of surface-enhanced Raman scattering (SERS) substrates with high sensitivity and reproducibility. Taking advantage of the microstructure of polycrystalline ice, we developed a new method to assemble large area gold nanoparticle (AuNP) superstructures as SERS substrates without external templating and aggregating agent. The assembly was conducted by freezing AuNP colloid at -20 °C, which concentrated AuNPs in the ice veins and produced an AuNP superstructure upon thawing the ice. The AuNP superstructures exhibited high SERS activity with enhancement factors on the order of 7.63 × 10(7) owing to the high-density hot spots throughout the superstructures. The SERS activity was found to increase with particle size and aggregate size of AuNP superstructures. Besides, the substrates showed good uniformity and reproducibility with relative standard deviations of 11.9% and 12.4%, respectively. The substrates showed long-term stability, maintaining SERS activity over a period of five months without noticeable change in morphology of the superstructures. The substrates was further used for label-free detection of trace Thiram on apple fruit with high sensitivity down to the concentration of 0.28 ng/cm(2), offering great potential to monitor Thiram levels in foodstuffs and environmental samples.

  11. AC electrophoretic deposition of organic-inorganic composite coatings.

    PubMed

    Yoshioka, T; Chávez-Valdez, A; Roether, J A; Schubert, D W; Boccaccini, A R

    2013-02-15

    Alternating current electrophoretic deposition (AC-EPD) of polyacrylic acid (PAA)-titanium oxide (TiO(2)) nanoparticle composites on stainless steel electrodes was investigated in basic aqueous solution. AC square wave with duty cycle of 80% was applied at a frequency of 1 kHz. FTIR-ATR spectra showed that both AC and direct current (DC) EPD successfully deposited PAA-TiO(2) composites. The deposition rate using AC-EPD was lower than that obtained in direct current DC-EPD. However, the microstructure and surface morphology of the deposited composite coatings were different depending on the type of electric field applied. AC-EPD applied for not more than 5 min led to smooth films without bubble formation, while DC-EPD for 1 min or more showed deposits with microstructural defects possibly as result of water electrolysis. AC-EPD was thus for the first time demonstrated to be a suitable technique to deposit organic-inorganic composite coatings from aqueous suspensions, showing that applying a square wave and frequency of 1 kHz leads to uniform PAA-TiO(2) composite coatings on conductive materials.

  12. SERS reveals the specific interaction of silver and gold nanoparticles with hemoglobin and red blood cell components.

    PubMed

    Drescher, Daniela; Büchner, Tina; McNaughton, Don; Kneipp, Janina

    2013-04-21

    The interaction of nanoparticles with hemoglobin (Hb), a major constituent of red blood cells, is important in nanotoxicity research. We report SERS spectra of Hb using gold and silver nanoparticles at very small nanoparticle : Hb molecule ratios, that is, under conditions relevant for SERS-based nanotoxicity experiments with red blood cells at high sensitivity. We show that the structural information obtained from the experiment is highly dependent on the type of SERS substrate and the conditions under which the interaction of nanoparticles with Hb molecules takes place. In experiments with isolated red blood cells, we demonstrate that the dependence of the spectra on the type of nanoparticle used as the SERS substrate extends to whole red blood cells and red blood cell components. Regarding the applicability of SERS to red blood cells in vivo, evidence is provided that the molecular information contained in the spectra is highly dependent on the material and size of the nanoparticles. The results indicate specific interactions of gold and silver nanoparticles with Hb and the red blood cell membrane, and reflect the hemolytic activity of silver nanoparticles. The results of this study help improve our understanding of the interactions of silver and gold nanoparticles with red blood cells.

  13. New insights into organic-inorganic hybrid perovskite CH3NH3PbI3 nanoparticles. An experimental and theoretical study of doping in Pb2+ sites with Sn2+, Sr2+, Cd2+ and Ca2+

    NASA Astrophysics Data System (ADS)

    Navas, Javier; Sánchez-Coronilla, Antonio; Gallardo, Juan Jesús; Cruz Hernández, Norge; Piñero, Jose Carlos; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; de Los Santos, Desireé M.; Aguilar, Teresa; Martín-Calleja, Joaquín

    2015-03-01

    This paper presents the synthesis of the organic-inorganic hybrid perovskite, CH3NH3PbI3, doped in the Pb2+ position with Sn2+, Sr2+, Cd2+ and Ca2+. The incorporation of the dopants into the crystalline structure was analysed, observing how the characteristics of the dopant affected properties such as the crystalline phase, emission and optical properties. XRD showed how doping with Sn2+, Sr2+ and Cd2+ did not modify the normal tetragonal phase. When doping with Ca2+, the cubic phase was obtained. Moreover, DR-UV-Vis spectroscopy showed how the band gap decreased with the dopants, the values following the trend Sr2+ < Cd2+ < Ca2+ < CH3NH3PbI3 ~ Sn2+. The biggest decrease was generated by Sr2+, which reduced the CH3NH3PbI3 value by 4.5%. In turn, cathodoluminescence (CL) measurements confirmed the band gap obtained. Periodic-DFT calculations were performed to understand the experimental structures. The DOS analysis confirmed the experimental results obtained using UV-Vis spectroscopy, with the values calculated following the trend Sn2+ ~ Pb2+ > Cd2+ > Sr2+ for the tetragonal structure and Pb2+ > Ca2+ for the cubic phase. The electron localization function (ELF) analysis showed similar electron localizations for undoped and Sn2+-doped tetragonal structures, which were different from those doped with Sr2+ and Cd2+. Furthermore, when Cd2+ was incorporated, the Cd-I interaction was strengthened. For Ca2+ doping, the Ca-I interaction had a greater ionic nature than Cd-I. Finally, an analysis based on the non-covalent interaction (NCI) index is presented to determine the weak-type interactions of the CH3NH3 groups with the dopant and I atoms. To our knowledge, this kind of analysis with these hybrid systems has not been performed previously.This paper presents the synthesis of the organic-inorganic hybrid perovskite, CH3NH3PbI3, doped in the Pb2+ position with Sn2+, Sr2+, Cd2+ and Ca2+. The incorporation of the dopants into the crystalline structure was analysed

  14. Dependence of SERS enhancement on the chemical composition and structure of Ag/Au hybrid nanoparticles

    NASA Astrophysics Data System (ADS)

    Chaffin, Elise; O'Connor, Ryan T.; Barr, James; Huang, Xiaohua; Wang, Yongmei

    2016-08-01

    Noble metal nanoparticles (NPs) such as silver (Ag) and gold (Au) have unique plasmonic properties that give rise to surface enhanced Raman scattering (SERS). Generally, Ag NPs have much stronger plasmonic properties and, hence, provide stronger SERS signals than Au NPs. However, Ag NPs lack the chemical stability and biocompatibility of comparable Au NPs and typically exhibit the most intense plasmonic resonance at wavelengths much shorter than the optimal spectral region for many biomedical applications. To overcome these issues, various experimental efforts have been devoted to the synthesis of Ag/Au hybrid NPs for the purpose of SERS detections. However, a complete understanding on how the SERS enhancement depends on the chemical composition and structure of these nanoparticles has not been achieved. In this study, Mie theory and the discrete dipole approximation have been used to calculate the plasmonic spectra and near-field electromagnetic enhancements of Ag/Au hybrid NPs. In particular, we discuss how the electromagnetic enhancement depends on the mole fraction of Au in Ag/Au alloy NPs and how one may use extinction spectra to distinguish between Ag/Au alloyed NPs and Ag-Au core-shell NPs. We also show that for incident laser wavelengths between ˜410 nm and 520 nm, Ag/Au alloyed NPs provide better electromagnetic enhancement than pure Ag, pure Au, or Ag-Au core-shell structured NPs. Finally, we show that silica-core Ag/Au alloy shelled NPs provide even better performance than pure Ag/Au alloy or pure solid Ag and pure solid Au NPs. The theoretical results presented will be beneficial to the experimental efforts in optimizing the design of Ag/Au hybrid NPs for SERS-based detection methods.

  15. Study of optical and physicochemical properties of colloidal silver nanoparticles as an efficient substrate for SERS

    NASA Astrophysics Data System (ADS)

    Cyrankiewicz, M.; Kruszewski, S.

    2011-04-01

    The unique optical and physicochemical properties of the noble metal colloidal nanoparticles enable their use in a wide range of applications, especially as a substrate in SERS and MEF study. The aim of this work is to characterize the conditions for the enhancement of Raman scattering by molecules adsorbed on silver surface. Silver sol is prepared by slightly modified Lee-Meisel's method and rhodamine 6G is used as a probe adsorbate. Pure colloidal silver suspension containing isolated nanoparticles exhibits relatively poor SERS efficiency. The extremely large electromagnetic field is induced in the junctions between two or more metallic nanocrystalites so some degree of their aggregation is necessary. The influence of potassium chloride and nitric acid as the aggregating agents is investigated here. The experiments show that both of them can promote the controlled aggregation process but chloride anions, unlike nitrate, much more effectively affect both electromagnetic and chemical mechanisms contributing to SERS. Due to the co-adsorption with rhodamine 6G they allow the dye molecules to directly interact with metallic surface. Moreover, the results clearly indicate that chloride in the presence of silver particles can induce the dimerization of the dye molecules.

  16. Anticorrosive organic/inorganic hybrid coatings

    NASA Astrophysics Data System (ADS)

    Gao, Tongzhai

    Organic/inorganic hybrid coating system was developed for anticorrosion applications using polyurea, polyurethane or epoxide as the organic phase and polysiloxane, formed by sol-gel process, as the inorganic phase. Polyurea/polysiloxane hybrid coatings were formulated and moisture cured using HDI isocyanurate, alkoxysilane-functionalized HDI isocyanurate, and tetraethyl orthosilicate (TEOS) oligomers. Two urethanes were prepared using the same components as abovementioned in addition to the oligoesters derived from either cyclohexane diacids (CHDA) and 2-butyl-2-ethyl-1,3-propanediol (BEPD) or adipic acid (AA), isophthalic acid (IPA), 1,6-hexanediol (HD), and trimethylol propane (TMP). Accelerated weathering and outdoor exposure were performed to study the weatherability of the polyurethane/polysiloxane hybrid coating system. FTIR and solid-state 13C NMR revealed that the degradation of the hybrid coatings occurred at the urethane and ester functionalities of the organic phase. DMA and DSC analyses showed the glass transition temperature increased and broadened after weathering. SEM was employed to observe the change of morphology of the hybrid coatings and correlated with the gloss variation after weathering. Rutile TiO2 was formulated into polyurethane/polysiloxane hybrid coatings in order to investigate the effect of pigmentation on the coating properties and the sol-gel precursor. Chemical interaction between the TiO2 and the sol-gel precursor was investigated using solid-state 29Si NMR and XPS. The morphology, mechanical, viscoelastic, thermal properties of the pigmented coatings were evaluated as a function of pigmentation volume concentration (PVC). Using AFM and SEM, the pigment were observed to be well dispersed in the polymer matrix. The thermal stability, the tensile modulus and strength of the coatings were enhanced with increasing PVC, whereas the pull-off adhesion and flexibility were reduced with increasing PVC. Finally, the pigmented coatings were

  17. A General Strategy to Prepare TiO2-core Gold-shell Nanoparticles as SERS-tags

    PubMed Central

    Li, Wenbing; Guo, Yanyan; Zhang, Peng

    2009-01-01

    The synthesis and characterization of TiO2-based core-shell nanoparticles as surface-enhanced Raman Scattering (SERS) tags are reported. A hydrolysis approach is first used to generate colloidal TiO2 nanoparticles, which are subsequently tagged with Raman probe molecules and encapsulated within a gold nanoshell. The resulting core-shell nanoparticles are characterized by using a number of techniques including UV-visible spectroscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy (EDX) to confirm the successful coating of the Au shells. These core-shell nanoparticles exhibit very strong and reproducible SERS signals of the Raman probe molecules. Three different types of Raman probe molecules are used to prepare different SERS-active nanoparticles (SERS-tags), which demonstrates the versatility of the design. Such TiO2-based metal-coated core-shell nanoparticles will be useful as SERS-tags in biological assay and imaging applications. They may also provide a platform for fundamental studies in the ongoing investigations on the mechanisms of SERS. PMID:20473348

  18. A General Strategy to Prepare TiO(2)-core Gold-shell Nanoparticles as SERS-tags.

    PubMed

    Li, Wenbing; Guo, Yanyan; Zhang, Peng

    2010-04-29

    The synthesis and characterization of TiO(2)-based core-shell nanoparticles as surface-enhanced Raman Scattering (SERS) tags are reported. A hydrolysis approach is first used to generate colloidal TiO(2) nanoparticles, which are subsequently tagged with Raman probe molecules and encapsulated within a gold nanoshell. The resulting core-shell nanoparticles are characterized by using a number of techniques including UV-visible spectroscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy (EDX) to confirm the successful coating of the Au shells. These core-shell nanoparticles exhibit very strong and reproducible SERS signals of the Raman probe molecules. Three different types of Raman probe molecules are used to prepare different SERS-active nanoparticles (SERS-tags), which demonstrates the versatility of the design. Such TiO(2)-based metal-coated core-shell nanoparticles will be useful as SERS-tags in biological assay and imaging applications. They may also provide a platform for fundamental studies in the ongoing investigations on the mechanisms of SERS.

  19. Determination of acetylsalicylic acid in commercial tablets by SERS using silver nanoparticle-coated filter paper.

    PubMed

    Sallum, Loriz Francisco; Soares, Frederico Luis Felipe; Ardila, Jorge Armando; Carneiro, Renato Lajarim

    2014-12-10

    In this work, filter paper was used as a low cost substrate for silver nanoparticles in order to perform the detection and quantification of acetylsalicylic acid by SERS in a commercial tablet. The reaction conditions were 150mM of ammonium hydroxide, 50mM of silver nitrate, 500mM of glucose, 12min of the reaction time, 45°C temperature, pretreatment with ammonium hydroxide and quantitative filter paper (1-2μm). The average size of silver nanoparticles deposited on the paper substrate was 180nm. Adsorption time of acetylsalicylic acid on the surface of the silver-coated filter paper was studied and an adsorption time of 80min was used to build the analytical curve. It was possible to obtain a calibration curve with good precision with a coefficient of determination of 0.933. The method proposed in this work was capable to quantify acetylsalicylic acid in commercial tablets, at low concentration levels, with relative error of 2.06% compared to the HPLC. The preparation of filter paper coated with silver nanoparticles using Tollen's reagent presents several advantages such as low cost of synthesis, support and reagents; minimum amount of residuals, which are easily treated, despite the SERS spectroscopy presenting fast analysis, with low sample preparation and low amount of reactants as in HPLC analysis.

  20. Determination of acetylsalicylic acid in commercial tablets by SERS using silver nanoparticle-coated filter paper

    NASA Astrophysics Data System (ADS)

    Sallum, Loriz Francisco; Soares, Frederico Luis Felipe; Ardila, Jorge Armando; Carneiro, Renato Lajarim

    2014-12-01

    In this work, filter paper was used as a low cost substrate for silver nanoparticles in order to perform the detection and quantification of acetylsalicylic acid by SERS in a commercial tablet. The reaction conditions were 150 mM of ammonium hydroxide, 50 mM of silver nitrate, 500 mM of glucose, 12 min of the reaction time, 45 °C temperature, pretreatment with ammonium hydroxide and quantitative filter paper (1-2 μm). The average size of silver nanoparticles deposited on the paper substrate was 180 nm. Adsorption time of acetylsalicylic acid on the surface of the silver-coated filter paper was studied and an adsorption time of 80 min was used to build the analytical curve. It was possible to obtain a calibration curve with good precision with a coefficient of determination of 0.933. The method proposed in this work was capable to quantify acetylsalicylic acid in commercial tablets, at low concentration levels, with relative error of 2.06% compared to the HPLC. The preparation of filter paper coated with silver nanoparticles using Tollen's reagent presents several advantages such as low cost of synthesis, support and reagents; minimum amount of residuals, which are easily treated, despite the SERS spectroscopy presenting fast analysis, with low sample preparation and low amount of reactants as in HPLC analysis.

  1. Antibacterial effect of various shapes of silver nanoparticles monitored by SERS.

    PubMed

    El-Zahry, Marwa R; Mahmoud, Amer; Refaat, Ibrahim H; Mohamed, Horria A; Bohlmann, Holger; Lendl, Bernhard

    2015-06-01

    A comparative evaluation of antimicrobial effect of synthesized silver nanoparticles (AgNPs) of different shapes using different methods was performed. Spherical, triangular and hexagonal AgNPs with an average size of 40 nm were chemically prepared and characterized by transmission electron microscope (TEM) and UV-visible spectroscopy. The antimicrobial effect of these different AgNPs against the gram negative bacterium Escherichia coli (E. coli) was studied by surface enhanced Raman spectroscopy (SERS), the evaluation of growth curves and inhibition zones. SERS proved to be sensitive to monitor the changes that occurred in the bacterial cells upon interaction with AgNPs, which qualitatively compared well with the data provided by the reference methods. However, as SERS is already sensitive to initial changes in the chemistry of bacteria due to the antibacterial effect of the AgNPs, fast and detailed information is provided by SERS as opposed to the classical reference methods based on the evaluation of growth curves and inhibition zones. The results of this work also demonstrate that hexagonal AgNPs display the highest antibacterial effect when compared to other NPs shapes, with triangular AgNPs exhibiting no antibacterial effect under the adopted conditions.

  2. Fabrication of Gold Nanoparticles/Graphene-PDDA Nanohybrids for Bio-detection by SERS Nanotechnology

    NASA Astrophysics Data System (ADS)

    Mevold, Andreas H. H.; Hsu, Wei-Wu; Hardiansyah, Andri; Huang, Li-Ying; Yang, Ming-Chien; Liu, Ting-Yu; Chan, Tzu-Yi; Wang, Kuan-Syun; Su, Yu-An; Jeng, Ru-Jong; Wang, Juen-Kai; Wang, Yuh-Lin

    2015-10-01

    In this research, graphene nanosheets were functionalized with cationic poly (diallyldimethylammonium chloride) (PDDA) and citrate-capped gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) bio-detection application. AuNPs were synthesized by the traditional citrate thermal reduction method and then adsorbed onto graphene-PDDA nanohybrid sheets with electrostatic interaction. The nanohybrids were subject to characterization including X-ray diffraction (XRD), transmission electron microscopy (TEM), zeta potential, and X-ray photoelectron spectroscopy (XPS). The results showed that the diameter of AuNPs is about 15-20 nm immobilized on the graphene-PDDA sheets, and the zeta potential of various AuNPs/graphene-PDDA ratio is 7.7-38.4 mV. Furthermore, the resulting nanohybrids of AuNPs/graphene-PDDA were used for SERS detection of small molecules (adenine) and microorganisms ( Staphylococcus aureus), by varying the ratios between AuNPs and graphene-PDDA. AuNPs/graphene-PDDA in the ratio of AuNPs/graphene-PDDA = 4:1 exhibited the strongest SERS signal in SERS detection of adenine and S. aureus. Thus, it is promising in the application of rapid and label-free bio-detection of bacteria or tumor cells.

  3. Special section guest editorial: Hybrid organic-inorganic solar cells

    DOE PAGES

    Nogueira, Ana Flavia; Rumbles, Garry

    2015-04-06

    In this special section of the Journal of Photonics for Energy, there is a focus on some of the science and technology of a range of different hybrid organic-inorganic solar cells. Prior to 1991 there were many significant scientific research reports of hybrid organic-inorganic solar cells; finally, however, it wasn’t until the dye-sensitized solar cell entered the league table of certified research cell efficiencies that this area experienced an explosion of research activity.

  4. Surface-immobilized polyampholytic silver nanoparticles for SERS detection of cations and anions in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Tan, Siliu; Pristinski, Denis; Sukhishvili, Svetlana; Du, Henry

    2005-11-01

    A new procedure was used for the preparation of stable silver colloids by reduction of silver nitrate with (N (2 hydroxyethyl) piperazine N'-2 ethanesulfonic acid (HEPES). The nanoparticle size and the surface charge could be tuned by changing the initial pH of a HEPES solution. Rhodamine 6G and NaSCN were used respectively as model cationic and anionic analytes to study the effect of surface charge of the silver colloids on detection sensitivity. The silver colloids exhibit SERS activity comparable to those obtained by the popular Lee-Meisel approach. The combination of the high SERS sensitivity and the ability to control the nature of surface charge renders HEPES-reduced polyampholytic silver colloids a potentially powerful platform for sensing and detection of both cations and anions in aqueous solutions.

  5. Metanephrine neuroendocrine tumor marker detection by SERS using Au nanoparticle/Au film sandwich architecture.

    PubMed

    Boca, Sanda; Farcau, Cosmin; Baia, Monica; Astilean, Simion

    2016-02-01

    Neuroendocrine tumors, such as pheochromocytoma or paraganglioma, are dangerous tumors that constitute a potential threat for a large number of patients. Currently, the biochemical diagnosis of neuroendocrine tumors is based on measurement of the direct secretory products of the adrenomedullary-sympathetic system or of their metabolites, such as catecholamines or their metanephrine derivatives, from plasma or urine. The techniques used for analysis of plasma free metanephrines, i.e. high-performance liquid chromatography or high-performance liquid chromatography coupled with mass-spectrometry are technically-demanding and time consuming, which limit their availability. Here we demonstrate a simple, fast and low-cost method for detecting metanephrine by Surface Enhanced Raman Scattering (SERS). The protocol consists in using evaporation-induced self-assembly of gold (Au) nanoparticles incubated with the analyte, on planar gold films. The assembly process produces regions with a dense distribution of both inter-particle gaps and particle-film gaps. Finite-difference time-domain simulations confirm that both kinds of gaps are locations of enhanced electromagnetic fields resulting from inter-particle and particle-film plasmonic coupling, useful for SERS amplification. Metanephrine vibrational bands assignment was performed according to density functional theory calculations. Metanephrine metabolite was detected in liquid at concentration levels lower than previously reported for other similar metabolites. The obtained results demonstrate that the Au nanoparticle/Au film exhibits noticeable SERS amplification of the adsorbed metabolite and can be used in the design of efficient, stable SERS-active substrates for the detection and identification of specific tumor markers.

  6. Organic-Inorganic Hydrophobic Nanocomposite Film with a Core-Shell Structure.

    PubMed

    Liu, Peng; Chen, Ying; Yu, Zhiwu

    2016-12-17

    A method to prepare novel organic-inorganic hydrophobic nanocomposite films was proposed by a site-specific polymerization process. The inorganic part, the core of the nanocomposite, is a ternary SiO₂-Al₂O₃-TiO₂ nanoparticles, which is grafted with methacryloxy propyl trimethoxyl silane (KH570), and wrapped by fluoride and siloxane polymers. The synthesized samples are characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrscopy, X-ray diffractometry (XRD), contact angle meter (CA), and scanning electron microscope (SEM). The results indicate that the novel organic-inorganic hydrophobic nanocomposite with a core-shell structure was synthesized successfully. XRD analysis reveals the nanocomposite film has an amorphous structure, and FTIR analysis indicates the nanoparticles react with a silane coupling agent (methacryloxy propyl trimethoxyl silane KH570). Interestingly, the morphology of the nanoparticle film is influenced by the composition of the core. Further, comparing with the film synthesized by silica nanoparticles, the film formed from SiO₂-Al₂O₃-TiO₂ nanoparticles has higher hydrophobic performance, i.e., the contact angle is greater than 101.7°. In addition, the TEM analysis reveals that the crystal structure of the particles can be changed at high temperatures.

  7. SERS active silver nanoparticles synthesized by inkjet printing on mesoporous silicon

    PubMed Central

    2014-01-01

    Inkjet printing technique is exploited for the synthesis of Ag nanoparticles (NPs) patterned on electrochemically etched silicon-based substrates. The nanostructure morphology, here analyzed by scanning electron microscopy, is dictated by the ink composition and the printing parameters. Under suitable excitation conditions, resonant surface-enhanced Raman scattering (SERS) performed on such metal-dielectric nanostructures can approach single-molecule detection as recently demonstrated on silvered porous silicon synthesized by immersion plating. PACS 78.67.Bf; 78.30.-j PMID:25288917

  8. Nanoparticle-nanoparticle vs. nanoparticle-substrate hot spot contributions to the SERS signal: studying Raman labelled monomers, dimers and trimers.

    PubMed

    Sergiienko, Sergii; Moor, Kamila; Gudun, Kristina; Yelemessova, Zarina; Bukasov, Rostislav

    2017-02-08

    We used a combination of Raman microscopy, AFM and TEM to quantify the influence of dimerization on the surface enhanced Raman spectroscopy (SERS) signal for gold and silver nanoparticles (NPs) modified with Raman reporters and situated on gold, silver, and aluminum films and a silicon wafer. The overall increases in the mean SERS enhancement factor (EF) upon dimerization (up by 43% on average) and trimerisation (up by 96% on average) of AuNPs and AgNPs on the studied metal films are within a factor of two, which is moderate when compared to most theoretical models. However, the maximum ratio of EFs for some dimers to the mean EF of monomers can be as high as 5.5 for AgNPs on a gold substrate. In contrast, for dimerization and trimerization of gold and silver NPs on silicon, the mean EF increases by 1-2 orders of magnitude relative to the mean EF of single NPs. Therefore, hot spots in the interparticle gap between gold nanoparticles rather than hot spots between Au nanoparticles and the substrate dominate SERS enhancement for dimers and trimers on a silicon substrate. However, Raman labeled noble metal nanoparticles on plasmonic metal films generate on average SERS enhancement of the same order of magnitude for both types of hot spot zones (e.g. NP/NP and NP/metal film).

  9. SERS-based sandwich immunoassay using antibody coated magnetic nanoparticles for Escherichia coli enumeration.

    PubMed

    Guven, Burcu; Basaran-Akgul, Nese; Temur, Erhan; Tamer, Ugur; Boyaci, Ismail Hakki

    2011-02-21

    A method combining immunomagnetic separation (IMS) and surface-enhanced Raman scattering (SERS) was developed to enumerate Escherichia coli (E. coli). Gold-coated magnetic spherical nanoparticles were prepared by immobilizing biotin-labeled anti-E. coli antibodies onto avidin-coated magnetic nanoparticles and used in the separation and concentration of the E. coli cells. Raman labels have been constructed using rod shaped gold nanoparticles coated with 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB) and subsequently with a molecular recognizer. Then DTNB-labeled gold nanorods were interacted with gold-coated magnetic spherical nanoparticle-antibody-E. coli complex. The capture efficiency and calibration graphs were obtained and examined in different E. coli concentrations (10(1)-10(7) cfu mL(-1)). The correlation between the concentration of bacteria and SERS signal was found to be linear within the range of 10(1)-10(4) cfu mL(-1) (R(2) = 0.992). The limit of detection (LOD) and limit of quantification (LOQ) values of the developed method were found to be 8 and 24 cfu mL(-1), respectively. The selectivity of the developed immunoassay was examined with Enterobacter aerogenes, Enterobacter dissolvens, and Salmonella enteriditis which did not produce any significant response. The ability of the immunoassay to detect E. coli in real water samples was also investigated and the results were compared with the experimental results from plate-counting methods. There was no significant difference between the methods that were compared (p > 0.05). This method is rapid and sensitive to target organisms with a total analysis time of less than 70 min.

  10. Instant synthesis of gold nanoparticles at room temperature and SERS applications

    NASA Astrophysics Data System (ADS)

    Britto Hurtado, R.; Cortez-Valadez, M.; Ramírez-Rodríguez, L. P.; Larios-Rodriguez, Eduardo; Alvarez, Ramón A. B.; Rocha-Rocha, O.; Delgado-Beleño, Y.; Martinez-Nuñez, C. E.; Arizpe-Chávez, H.; Hernández-Martínez, A. R.; Flores-Acosta, M.

    2016-08-01

    Nowadays, gold nanoparticles (AuNps) can be used in a variety of applications, thus efficient methods to produce them are necessary. Several methods have been proposed in this area, but NPs production time is one limitation of these approaches. In this study, we propose a high competitive method to synthesize gold colloidal nanoparticles, instantaneously, using no-toxic reducing agents. These substances allow the instantaneous synthesis at room temperature, even without magnetic stirrers, ovens or ultrasonic baths. Optic analysis showed two absorption bands, associated with surface Plasmon as function of HAuCl4 concentration. The nanoparticles synthesized have a 10-20 nm size, seen by the transmission electron microscopy (TEM). Therefore, it was possible to obtain several geometric patterns of AuNps, and the synthesis was performed reducing significantly processing time. Additionally, Mie and Fuchs theories were used to predict the location of the absorption bands linked to the plasmon surface in gold nanoparticles. The Surface Enhanced Raman Spectroscopy (SERS) effect was analyzed considering natural zeolite (Chabazite) as analyte, in order to determinate its possible application in soil analysis.

  11. A facile surface-enhanced Raman scattering (SERS) detection of rhodamine 6G and crystal violet using Au nanoparticle substrates

    NASA Astrophysics Data System (ADS)

    Zhang, Kuibao; Zeng, Tixian; Tan, Xiulan; Wu, Weidong; Tang, Yongjian; Zhang, Haibin

    2015-08-01

    In this study, Au nanoparticle (5 nm) colloid was employed for a facile preparation of SERS substrates from three approaches: (1) original Au nanoparticles, (b) Au colloid coated 200 nm polystyrene (PS) beads, and (3) Au colloid annealed at 200-500 °C. Rhodamine 6G (R6G) and crystal violet were employed as the Raman active probes. The Au colloid deposited PS beads (PS@Au) exhibit intensive SERS signal for R6G detection, which is promising for crystal violet detection after being annealed at 400 °C. The 200 °C annealed Au nanoparticles demonstrate excellent combined SERS sensitivity for both R6G and crystal violet. For the original Au colloid, elevated annealing temperature from 200 °C to 500 °C decreases the SERS intensity as Au particles were coarsened gradually.

  12. 'Green' biocompatible organic-inorganic hybrid electrospun nanofibers for potential biomedical applications.

    PubMed

    Manjumeena, R; Elakkiya, T; Duraibabu, D; Feroze Ahamed, A; Kalaichelvan, P T; Venkatesan, R

    2015-02-01

    Gold nanoparticles were prepared by green route using Couroupita guianensis leaves extract. The green synthesized gold nanoparticles exhibited maximum absorbance at 526 nm in the ultraviolet spectrum. By incorporating the green synthesized gold nanoparticles in poly(vinyl alcohol) matrix, unique green organic-inorganic hybrid nanofibers (poly (vinyl alcohol : )-gold nanoparticles) were developed by electrospinning. Contact angle measurements showed that the prepared poly (vinyl alcohol)-gold nanoparticles were found to be highly hydrophilic. The crystallinity of gold nanoparticles was analyzed using XRD. The synthesized gold nanoparticles and poly (vinyl alcohol)-gold nanoparticles were characterized using high-resolution transmission electron microscope, Fourier transform-infrared spectroscopy and energy-dispersive analysis of X-ray. The ultimate aim of the present work is to achieve optimum antibacterial, antifungal, biocompatibility and antiproliferative activities at a very low loading of gold nanoparticles. Vero cell lines showed a maximum of 90% cell viability on incubation with the prepared poly (vinyl alcohol)-gold nanoparticles. MCF 7 and HeLa cell lines proliferated only to 8% and 9%, respectively, on incubation with the poly (vinyl alcohol)-gold nanoparticles, and also exhibited good antibacterial and antifungal activities against test pathogenic bacterial and fungal strains. Thus, the poly (vinyl alcohol)-gold nanoparticles could be used for dual applications such as antimicrobial, anticancer treatment besides being highly biocompatible. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  13. Facile fabrication of silver nanoparticles with temperature-responsive sizes as highly active SERS substrates

    NASA Astrophysics Data System (ADS)

    Wu, Jing; Fang, Jinghuai; Cheng, Mingfei; Gong, Xiao

    2016-12-01

    In our work, large-scale silver NPs (nanoparticles) are successfully synthesized on zinc foils with controllable size by regulating the temperature of the displacement reaction. Our results show that when the temperature is 70 °C, the average size of silver NPs is approximately 88 nm in diameter, and they exhibit the strongest SERS activity. The gap between nanoparticles is simultaneously regulated as near as possible, which produces abundant "hot spots" and nanogaps. Crystal violet (CV) was used as probe molecules, and the SERS signals show that the values of relative standard deviation in the intensity of the main vibration modes are less than 10%, demonstrating excellent reproducibility of the silver NPs. Furthermore, the high surface-average enhancement factor of 3.86 × 107 is achieved even when the concentration of CV is 10-7 M, which is sufficient for single-molecule detection. We believe that this low cost and rapid route would get wide applications in chemical synthesis.

  14. Surface-enhanced Raman spectroscopy (SERS) to detect natural organic coatings on silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Kühn, Melanie; Ivleva, Natalia P.; Klitzke, Sondra; von der Kammer, Frank; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    Applications for engineered inorganic nanoparticles (EINP) are rising and causing a higher risk for EINP to be released into the environment. Their stability and transport behaviour under environmental conditions is strongly depending on their surface properties which on the other hand depend on the presence or absence of a surface coating. We assume that EINP get coated soon after their release into the environment e.g. by humic substances like humic or fulvic acids and NOM. Often EINP are stabilized by a coating agent like citrate or polyvinylpyrrolidone. Therefore, the replacement of the initial coating material or a multilayer coating has to be considered. Characterization of natural coatings on EINP is crucial to predict their environmental behaviour, but analytical methods to investigate organic coatings are scarce. To investigate humic- and fulvic acid coatings on silver nanoparticles (Ag NP) Raman micro-spectroscopy (RM) was used. RM is limited in its sensitivity, but silver nanoparticles cause an enhancement of the Raman signal of adsorbed substances by a factor of 103-106, so called surface-enhanced Raman spectroscopy (SERS). The Raman spectrum of humic acids is dominated by the carbonaceous parts of the humic acids which are known from carbon analysis and referred to as defect (D) and graphite (G) peak of carbon. Humic acids of different origin (humic acid from a lignite, suwannee river humic acid) showed differences in the D and G ratios indicating a difference in the structure of the contained carbon. With SERS humic and fulvic acid coatings on Ag NP were analysed: 1-100 mg/L humic acid stock solution were mixed with citrate and hydroxylammoniumchloride stabilized Ag NP, centrifuged and resuspended in deionized water (washing) to remove all coating material not associated with Ag NP. This washing step was repeated up to four times. SERS prooved that the coating was still present after the fourth washing step. As SERS is only sensitive for substances in

  15. Synthesis and improved SERS performance of silver nanoparticles-decorated surface mesoporous silica microspheres

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; Wang, Xiaolong; Zhang, Li; Zhou, Jun; Zhao, Ziqi

    2016-08-01

    This study reported the improved Raman enhancement ability of silver nanoparticles (Ag NPs) decorated on surface mesoporous silica microspheres (MSiO2@Ag) than that of Ag NPs on solid silica microspheres (SSiO2@Ag). These two kinds of hybrid structures were prepared by a facile single-step hydrothermal reaction with polyvinylpyrrolidone (PVP) serves as both a reductant and stabilizer. The as-synthesized MSiO2@Ag microspheres show more significant surface-enhanced Raman scattering (SERS) activity for 4-mercaptobenzoic acid (4MBA) than SSiO2@Ag microspheres with enhancement factors as 9.20 × 106 and 4.39 × 106, respectively. The proposed reason for the higher SERS activity is estimated to be the contribution of more Raman probe molecules at the mesoporous channels where an enhanced electromagnetic field exists. Such a field was identified by theoretical calculation result. The MSiO2@Ag microspheres were eventually demonstrated for the SERS detection of a typical chemical toxin namely methyl parathion with a detection limit as low as 1 × 10-3 ppm, showing its promising potential in biosensor application.

  16. The application of Silver nanoparticle based SERS in diagnosing thyroid tissue

    NASA Astrophysics Data System (ADS)

    Huang, Zufang; Li, Zuanfang; Chen, Rong; Chen, Guannan; Lin, Duo; Xi, Gangqin; Chen, Yongjian; Lin, Hongxin; Lei, Jinping

    2011-01-01

    Surface-enhanced Raman scattering (SERS) is proved to be a powerful analytical tool for investigation of biological tissue. In this study, SERS based on Ag nanoparticles was used to investigate the normal and cancerous thyroid tissue. Preliminary results indicated that Raman peaks and the spectra profile from both normal and cancerous tissues showed a basic similarity, obvious differences are that, first, Raman peaks 563cm-1, 1449cm-1 and 1587cm-1 in cancerous tissue decreased obviously compared with the normal thyroid tissue. Besides, Raman peaks 1004cm-1 and 1128cm-1 might be specific peaks for normal thyroid tissue, whereas 1294cm-1 might attribute to specific peak for cancerous thyroid tissue. In addition, some peaks in normal thyroid tissue appeared to have shifted in cancerous tissue. Intensity ratio of 656cm-1 vs. 725cm-1 in normal tissue are significantly different from cancerous tissue (P<0.005), and it can be a reference for spectroscopic diagnostics of thyroid tissue. This study demonstrates that SERS can be used to monitor the changes at molecular level as well as a complementary tool in thyroid histopathology.

  17. SERS and DFT study of water on metal cathodes of silver, gold and platinum nanoparticles.

    PubMed

    Li, Jian-Feng; Huang, Yi-Fan; Duan, Sai; Pang, Ran; Wu, De-Yin; Ren, Bin; Xu, Xin; Tian, Zhong-Qun

    2010-03-14

    The observed surface-enhanced Raman scattering (SERS) spectra of water adsorbed on metal film electrodes of silver, gold, and platinum nanoparticles were used to infer interfacial water structures on the basis of the change of the electrochemical vibrational Stark tuning rates and the relative Raman intensity of the stretching and bending modes. To explain the increase of the relative Raman intensity ratio of the bending and stretching vibrations at the very negative potential region, density functional theory calculations provide the conceptual model. The specific enhancement effect for the bending mode was closely associated with the water adsorption structure in a hydrogen bonded configuration through its H-end binding to surface sites with large polarizability due to strong cathodic polarization. The present results allow us to propose that interfacial water molecules exist on these metal cathodes with different hydrogen bonding interactions, i.e., the HO-HH-Pt dihydrogen bond for platinum and the HO-HAg(Au) for silver and gold. This dihydrogen bonding configuration on platinum is further supported from observation of the Pt-H stretching band. Furthermore, the influences of the pH effect on SERS intensity and vibrational Stark effect on the gold electrode indicate that the O-H stretching SERS signals are enhanced in the alkaline solutions because of the hydrated hydroxide surface species adsorbed on the gold cathode.

  18. Self-assembled large Au nanoparticle arrays with regular hot spots for SERS.

    SciTech Connect

    Chen, A.; DePrince III, A. E.; Demortiere, A.; Joshi-Imre, A.; Shevchenko, E. V.; Gray, S.K.; Welp, U.; Vlasko-Vlasov, V. K.

    2011-08-22

    The cost-effective self-assembly of 80 nm Au nanoparticles (NPs) into large-domain, hexagonally close-packed arrays for high-sensitivity and high-fidelity surface-enhanced Raman spectroscopy (SERS) is demonstrated. These arrays exhibit specific optical resonances due to strong interparticle coupling, which are well reproduced by finite-difference time-domain (FDTD) simulations. The gaps between NPs form a regular lattice of hot spots that enable a large amplification of both photoluminescence and Raman signals. At smaller wavelengths the hot spots are extended away from the minimum-gap positions, which allows SERS of larger analytes that do not fit into small gaps. Using CdSe quantum dots (QDs) a 3-5 times larger photoluminescence enhancement than previously reported is experimentally demonstrated and an unambiguous estimate of the electromagnetic SERS enhancement factor of {approx}10{sup 4} is obtained by direct scanning electron microscopy imaging of QDs responsible for the Raman signal. Much stronger enhancement of {approx}10{sup 8} is obtained at larger wavelengths for benzenethiol molecules penetrating the NP gaps.

  19. In vivo multiplexed molecular imaging of esophageal cancer via spectral endoscopy of topically applied SERS nanoparticles

    PubMed Central

    Wang, Yu Winston; Kang, Soyoung; Khan, Altaz; Bao, Philip Q.; Liu, Jonathan T.C.

    2015-01-01

    The biological investigation and detection of esophageal cancers could be facilitated with an endoscopic technology to screen for the molecular changes that precede and accompany the onset of cancer. Surface-enhanced Raman scattering (SERS) nanoparticles (NPs) have the potential to improve cancer detection and investigation through the sensitive and multiplexed detection of cell-surface biomarkers. Here, we demonstrate that the topical application and endoscopic imaging of a multiplexed cocktail of receptor-targeted SERS NPs enables the rapid detection of tumors in an orthotopic rat model of esophageal cancer. Antibody-conjugated SERS NPs were topically applied on the lumenal surface of the rat esophagus to target EGFR and HER2, and a miniature spectral endoscope featuring rotational scanning and axial pull-back was employed to comprehensively image the NPs bound on the lumen of the esophagus. Ratiometric analyses of specific vs. nonspecific binding enabled the visualization of tumor locations and the quantification of biomarker expression in agreement with immunohistochemistry and flow cytometry validation data. PMID:26504623

  20. Surgical Guidance via Multiplexed Molecular Imaging of Fresh Tissues Labeled with SERS-Coded Nanoparticles

    PubMed Central

    Wang, Yu; Kang, Soyoung; Doerksen, Josh D.; Glaser, Adam K.

    2016-01-01

    The imaging of dysregulated cell-surface receptors (or biomarkers) is a potential means of identifying the presence of cancer with high sensitivity and specificity. However, due to heterogeneities in the expression of protein biomarkers in tumors, molecular imaging technologies should ideally be capable of visualizing a multiplexed panel of cancer biomarkers. Recently, surface-enhanced Raman-scattering (SERS) nanoparticles (NPs) have attracted wide interest due to their potential for sensitive and multiplexed biomarker detection. In this review, we focus on the most recent advances in tumor imaging using SERS-coded NPs. A brief introduction of the structure and optical properties of SERS NPs is provided, followed by a detailed discussion of key imaging issues such as the administration of NPs in tissue (topical versus systemic), the optical configuration and imaging approach of Raman imaging systems, spectral demultiplexing methods for quantifying NP concentrations, and the disambiguation of specific vs. nonspecific sources of contrast through ratiometric imaging of targeted and untargeted (control) NP pairs. Finally, future challenges and directions are briefly outlined. PMID:27524875

  1. Surface-enhanced Raman scattering (SERS) detection of multiple viral antigens using magnetic capture of SERS-active nanoparticles

    USDA-ARS?s Scientific Manuscript database

    A highly sensitive immunoassay based on surface-enhanced Raman scattering (SERS) spectroscopy has been developed for multiplex detection of surface envelope and capsid antigens of the viral zoonotic pathogens West Nile virus (WNV) and Rift Valley fever virus (RVFV). Detection was mediated by antibo...

  2. Core-shell of FePt@SiO2-Au magnetic nanoparticles for rapid SERS detection

    NASA Astrophysics Data System (ADS)

    Hardiansyah, Andri; Chen, An-Yu; Liao, Hung-Liang; Yang, Ming-Chien; Liu, Ting-Yu; Chan, Tzu-Yi; Tsou, Hui-Ming; Kuo, Chih-Yu; Wang, Juen-Kai; Wang, Yuh-Lin

    2015-10-01

    In this study, multifunctional hybrid nanoparticles composed of iron platinum (FePt), silica (SiO2), and gold nanoparticles (AuNPs) had been developed for surface-enhanced Raman scattering (SERS) application. Core-shell structure of SiO2 and FePt nanoparticles (FePt@SiO2) was fabricated through sol-gel process and then immobilized gold nanoparticles onto the surface of FePt@SiO2, which displays huge Raman enhancement effect and magnetic separation capability. The resulting core-shell nanoparticles were subject to evaluation by transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX), zeta potential measurement, and X-ray photoelectron spectroscopy (XPS). TEM observation revealed that the particle size of resultant nanoparticles displayed spherical structure with the size ~30 nm and further proved the successful immobilization of Au onto the surface of FePt@SiO2. Zeta potential measurement exhibited the successful reaction between FePt@SiO2 and AuNPs. The rapid SERS detection and identification of small biomolecules (adenine) and microorganisms (gram-positive bacteria, Staphylococcus aureus) was conducted through Raman spectroscopy. In summary, the novel core-shell magnetic nanoparticles could be anticipated to apply in the rapid magnetic separation under the external magnetic field due to the core of the FePt superparamagnetic nanoparticles and label-free SERS bio-sensing of biomolecules and bacteria.

  3. Polymer-coated surface enhanced Raman scattering (SERS) gold nanoparticles for multiplexed labeling of chronic lymphocytic leukemia cells

    NASA Astrophysics Data System (ADS)

    MacLaughlin, Christina M.; Parker, Edward P. K.; Walker, Gilbert C.; Wang, Chen

    2012-01-01

    The ease and flexibility of functionalization and inherent light scattering properties of plasmonic nanoparticles make them suitable contrast agents for measurement of cell surface markers. Immunophenotyping of lymphoproliferative disorders is traditionally undertaken using fluorescence detection methods which have a number of limitations. Herein, surface-enhanced Raman scattering (SERS) gold nanoparticles conjugated to monoclonal antibodies are used for the selective targeting of CD molecules on the surface of chronic lymphocytic leukemia (CLL) cells. Raman-active reporters were physisorbed on to the surface of 60 nm spherical Au nanoparticles, the particles were coated with 5kDa polyethylene glycol (PEG) including functionalities for conjugation to monoclonal IgG1 antibodies. A novel method for quantifying the number of antibodies bound to SERS probes on an individual basis as opposed to obtaining averages from solution was demonstrated using metal dots in transmission electron microscopy (TEM). The specificity of the interaction between SERS probes and surface CD molecules of CLL cells was assessed using Raman spectroscopy and dark field microscopy. An in-depth study of SERS probe targeting to B lymphocyte marker CD20 was undertaken, and proof-of-concept targeting using different SERS nanoparticle dyes specific for cell surface CD19, CD45 and CD5 demonstrated using SERS spectroscopy.

  4. SERS detection of bacteria in water by in situ coating with Ag nanoparticles.

    PubMed

    Zhou, Haibo; Yang, Danting; Ivleva, Natalia P; Mircescu, Nicoleta E; Niessner, Reinhard; Haisch, Christoph

    2014-02-04

    The bio-sensing for the convenient detection of bacteria has been widely explored with the use of various sensing materials and techniques. It is still a challenge to achieve an ultrasensitive and selective, but simple, rapid, and inexpensive detection method for bacteria. We report on surface-enhanced Raman scattering (SERS) for the detection of living bacteria in drinking water by employing a synthesis of silver nanoparticles coating the cell wall of bacteria. We found that the Raman signals intensity of bacteria after AgNP synthesis mainly depends on the zeta potential of the cell wall. The enhancement of the Raman signal of bacteria using this strategy is about 30-fold higher than that in the case of a simply mixed colloid-bacterial suspension. The total assay time required is only 10 min and the total reactants' volume needed to analyze bacteria in a real environment is as low as 1 mL. Particularly, only one droplet of 3 μL sample is necessary for each SERS measurement. Furthermore, we can use this novel strategy to discriminate three strains of Escherichia coli and one strain of Staphylococcus epidermidis by hierarchy cluster analysis. Finally, we can detect bacteria down to 2.5 × 10(2) cells/mL on a hydrophobic glass slide by SERS mapping. Thus, our detection method offers prominent advantages, such as reduced assay time, simple handling, low reactant volumes, small amount of sample, and higher sensitivity and selectivity compared to previously reported label free methods. This novel strategy may be extended to open an avenue for developing various SERS-based biosensors.

  5. Chitosan bio-based organic-inorganic hybrid aerogel microspheres.

    PubMed

    El Kadib, Abdelkrim; Bousmina, Mosto

    2012-07-02

    Recently, organic-inorganic hybrid materials have attracted tremendous attention thanks to their outstanding properties, their efficiency, versatility and their promising applications in a broad range of areas at the interface of chemistry and biology. This article deals with a new family of surface-reactive organic-inorganic hybrid materials built from chitosan microspheres. The gelation of chitosan (a renewable amino carbohydrate obtained by deacetylation of chitin) by pH inversion affords highly dispersed fibrillar networks shaped as self-standing microspheres. Nanocasting of sol-gel processable monomeric alkoxides inside these natural hydrocolloids and their subsequent CO(2) supercritical drying provide high-surface-area organic-inorganic hybrid materials. Examples including chitosan-SiO(2), chitosan-TiO(2), chitosan-redox-clusters and chitosan-clay-aerogel microspheres are described and discussed on the basis of their textural and structural properties, thermal and chemical stability and their performance in catalysis and adsorption.

  6. Sensitive and selective SERS probe for trivalent chromium detection using citrate attached gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Ye, Yingjie; Liu, Honglin; Yang, Liangbao; Liu, Jinhuai

    2012-09-01

    In this article, we have demonstrated a sensitive and selective surface enhanced Raman spectroscopy (SERS) probe, based on citrate-capped gold nanoparticles (AuNPs), for trivalent chromium (Cr3+) detection. After introducing Tween 20 to a solution of citrate-capped AuNPs, the as-prepared Tween 20/citrate-AuNP probe could recognize Cr3+ at a 50 × 10-9 M level in an aqueous medium at a pH of 6.0. Tween 20 can stabilize the citrate-capped AuNPs against conditions of high ionic strength. Due to the chelation between Cr3+ and citrate ions, AuNPs undergo aggregation. As a result, it formed several hot spots and provided a significant enhancement of the Raman signal intensity through electromagnetic (EM) field enhancements. A detailed mechanism for tremendous SERS intensity change had been discussed. The selectivity of this system toward Cr3+ was 400-fold, remarkably greater than other metal ions.In this article, we have demonstrated a sensitive and selective surface enhanced Raman spectroscopy (SERS) probe, based on citrate-capped gold nanoparticles (AuNPs), for trivalent chromium (Cr3+) detection. After introducing Tween 20 to a solution of citrate-capped AuNPs, the as-prepared Tween 20/citrate-AuNP probe could recognize Cr3+ at a 50 × 10-9 M level in an aqueous medium at a pH of 6.0. Tween 20 can stabilize the citrate-capped AuNPs against conditions of high ionic strength. Due to the chelation between Cr3+ and citrate ions, AuNPs undergo aggregation. As a result, it formed several hot spots and provided a significant enhancement of the Raman signal intensity through electromagnetic (EM) field enhancements. A detailed mechanism for tremendous SERS intensity change had been discussed. The selectivity of this system toward Cr3+ was 400-fold, remarkably greater than other metal ions. Electronic supplementary information (ESI) available: Fig. S1-S5. See DOI: 10.1039/c2nr31985c

  7. SERS Activity of Silver Nanoparticles Functionalized with A Desferrioxamine B Derived Ligand for FE(III) Binding and Sensing

    NASA Astrophysics Data System (ADS)

    Galinetto, P.; Taglietti, A.; Pasotti, L.; Pallavicini, P.; Dacarro, G.; Giulotto, E.; Grandi, M. S.

    2016-01-01

    We report the SERS activity of colloidal silver nanoparticles functionalized with a ligand, derived from the siderophore desferrioxamine B (desferal, DFO), an iron chelator widely used in biological and medical applications. The ligand was equipped with a sulfur-containing moiety to ensure optimal binding with silver surfaces. By means of Raman and SERS effects we monitored the route of material preparation from the modified DFO-S molecule to the colloidal aggregates. The results indicate that the functionalization of the chelating agent does not affect its binding ability towards Fe(III). The resulting functionalized silver nanoparticles are a promising SERS tag for operation in biological environments. The Fe-O stretching signature, arising when DFO-S grafted to silver nanoparticles binds Fe(III), could provide a tool for cation sensing in solution.

  8. Fabrication of chitosan-silver nanoparticle hybrid 3D porous structure as a SERS substrate for biomedical applications

    NASA Astrophysics Data System (ADS)

    Jung, Gyeong-Bok; Kim, Ji-Hye; Burm, Jin Sik; Park, Hun-Kuk

    2013-05-01

    We propose a simple, low-cost, large-area, and functional surface enhanced Raman scattering (SERS) substrate for biomedical applications. The SERS substrate with chitosan-silver nanoparticles (chitosan-Ag NPs) hybrid 3D porous structure was fabricated simply by a one-step method. The chitosan was used as a template for the Ag NPs deposition. SERS enhancement by the chitosan-Ag NPs substrate was experimentally verified using rhodamine B as an analyte. Thiolated single stranded DNA was also measured for atopic dermatitis genetic markers (chemokines CCL17) at a low concentration of 5 pM. We successfully designed a novel SERS substrate with silver nanoparticle hybridized 3D porous chitosan that has the potential to become a highly sensitive and selective tool for biomedical applications.

  9. Covalently functionalized noble metal nanoparticles for molecular imprinted polymer biosensors: Synthesis, characterization, and SERS detection

    NASA Astrophysics Data System (ADS)

    Volkert, Anna Allyse

    This dissertation evaluates how gold nanoparticle structure and local environment influence resulting sensor function when using these nanomaterials for complex sample analysis. Molecular imprinted polymers (MIPs), a class of plastic antibodies, are engineered and incorporated into these nanosensors thereby facilitating the quantitative detection of a variety of small molecules when Raman spectroscopy and surface enhanced Raman scattering (SERS) are used for detection. First, homogeneous seeded growth gold nanosphere synthesis is evaluated as a function of ionic double layer composition and thickness. Systematically increasing the citrate concentration during synthesis improves nanomaterial shape homogeneity; however, further elevations of citrate concentration increase the number of internal and/or external atomic defects in the nanomaterials which leads to decreasing solution-phase stability. Next, spherical gold nanoparticles are modified with self-assembled monolayer (SAM), modeled using interfacial energy calculations, and experimental characterized using transmission electron microscopy, NMR, extinction spectroscopy, zeta potential, X-ray photoelectron spectroscopy, and flocculation studies to assess the morphology, surface chemistry, optical properties, surface charge, SAM packing density, and nanoparticle stability, respectively. The number of molecules on the nanostructures increases with increasing ionic strength (by decreasing the electrostatic interfacial energy between assembled molecules) which subsequently promotes nanoparticle stability. Third, plastic antibodies that recognize three drugs commonly used to treat migraines are engineered. These methacrylate-based MIPs are synthesized, extracted, characterized, and used to quantitatively and directly detect over-the-counter drugs in complex samples using Raman microscopy. These results along with numerical approximation methods to estimate drug binding site densities and dissociation constants with

  10. Progress on lanthanide-based organic-inorganic hybrid phosphors.

    PubMed

    Carlos, Luís D; Ferreira, Rute A S; de Zea Bermudez, Verónica; Julián-López, Beatriz; Escribano, Purificación

    2011-02-01

    Research on organic-inorganic hybrid materials containing trivalent lanthanide ions (Ln(3+)) is a very active field that has rapidly shifted in the last couple of years to the development of eco-friendly, versatile and multifunctional systems, stimulated by the challenging requirements of technological applications spanning domains as diverse as optics, environment, energy, and biomedicine. This tutorial review offers a general overview of the myriad of advanced Ln(3+)-based organic-inorganic hybrid materials recently synthesised, which may be viewed as a major innovation in areas of phosphors, lighting, integrated optics and optical telecommunications, solar cells, and biomedicine.

  11. Atomic force microscopy of electrospun organic-inorganic lipid nanofibers

    NASA Astrophysics Data System (ADS)

    Zhang, Jinhong; Cohn, Celine; Qiu, Weiguo; Zha, Zhengbao; Dai, Zhifei; Wu, Xiaoyi

    2011-09-01

    An organic-inorganic hybridization strategy has been proposed to synthesize polymerizable lipid-based materials for the creation of highly stable lipid-mimetic nanostructures. We employ atomic force microscopy (AFM) to analyze the surface morphology and mechanical property of electrospun cholesteryl-succinyl silane (CSS) nanofibers. The AFM nanoindentation of the CSS nanofibers reveals elastic moduli of 55.3 ± 27.6 to 70.8 ± 35 MPa, which is significantly higher than the moduli of natural phospholipids and cholesterols. The study shows that organic-inorganic hybridization is useful in the design of highly stable lipid-based materials.

  12. Special section guest editorial: Hybrid organic-inorganic solar cells

    SciTech Connect

    Nogueira, Ana Flavia; Rumbles, Garry

    2015-04-06

    In this special section of the Journal of Photonics for Energy, there is a focus on some of the science and technology of a range of different hybrid organic-inorganic solar cells. Prior to 1991 there were many significant scientific research reports of hybrid organic-inorganic solar cells; finally, however, it wasn’t until the dye-sensitized solar cell entered the league table of certified research cell efficiencies that this area experienced an explosion of research activity.

  13. Quantitative determination of melamine in milk using Ag nanoparticle monolayer film as SERS substrate

    NASA Astrophysics Data System (ADS)

    Li, Ruoping; Yang, Jingliang; Han, Junhe; Liu, Junhui; Huang, Mingju

    2017-04-01

    A Raman method employing silver nanoparticle (Ag NP) monolayer film as Surface-enhanced Raman Scattering (SERS) substrate was presented to rapidly detect melamine in milk. The Ag NPs with 80 nm diameter were modified by polyvinylpyrrolidone to improve their uniformity and chemical stability. The treatment procedure of liquid milk required only addition of acetic acid and centrifugation, and required time is less than 15 min. The Ag NP monolayer film significantly enhanced Raman signal from melamine and allowed experimentally reproducible determination of the melamine concentration. A good linear relationship (R2=0.994) between the concentration and Raman peak intensity of melamine at 681 cm-1 was obtained for melamine concentrations between 0.10 mg L-1 and 5.00 mg L-1. This implies that this method can detect melamine concentrations below 1.0 mg L-1, the concentration currently considered unsafe.

  14. SERS detection and targeted ablation of lymphoma cells using functionalized Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Yao, Qian; Cao, Fei; Feng, Chao; Zhao, Yan; Wang, Xiuhong

    2016-03-01

    Lymphoma is a heterogeneous group of malignancies of the lymphoid tissue, and is prevalent worldwide affecting both children and adults with a high mortality rate. There is in dire need of accurate and noninvasive approaches for early detection of the disease. Herein, we report a facile way to fabricate silver nanoparticle based nanoprobe by incorporating the corner-stone immunotherapeutic drug Rituxan for simultaneous detection and ablation of lymphoma cells in vitro. The fabricated nanoprobe can detect CD20 positive single lymphoma cell by surface enhanced Raman scattering technique with high specificity. The engineered nanoprobe retains the same antibody property as intact drug via Antibody-Dependent Cell-mediated Cytotoxicity (ADCC) analysis. The nanoprobe efficiently eradicates lymphoma cells in vitro. By integrating the advantages of sensitive SERS detection with targeted ablation capabilities of immunotherapeutic drug through site specificity, this nanoprobe can be applied as outstanding tools in living imaging, cancer diagnosis and treatment.

  15. Arrangement and SERS Applications of Nanoparticle Clusters Using Liquid Crystalline Template.

    PubMed

    Kim, Dae Seok; Honglawan, Apiradee; Yang, Shu; Yoon, Dong Ki

    2017-02-16

    Manipulation of nanomaterials such as nanoparticles (NPs) and nanorods (NRs) to make clusters is of significant interest in material science and nanotechnology due to the unusual collective opto-electric properties in such structures that cannot be found in the individual NPs. This work demonstrates an effective way to arrange NP clusters (NPCs) to make the desired arrays based on removable and NP-guidable liquid crystalline template using sublimation and reconstruction phenomenon. The position of the NPCs is precisely controlled by the defect structure of the liquid crystal (LC), namely toric focal conic domains (TFCDs), during thermal annealing to construct the LC and corresponding NPC structures. As a proof of concept, the surface-enhanced Raman scattering (SERS) activity of a fabricated array of gold nanorod (GNR) clusters is measured and shown to have highly sensitive detection characteristics essential for potential sensing applications.

  16. SERS detection and antibacterial activity from uniform incorporation of Ag nanoparticles with aligned Si nanowires

    NASA Astrophysics Data System (ADS)

    Chen, Chia-Yun; Hsu, Li-Jen; Hsiao, Po-Hsuan; Yu, Chang-Tze Ricky

    2015-11-01

    We present a facile, reliable and controllable two-steps electroless deposition for uniformly decorating the silver (Ag) nanoparticles (NPs) on the highly aspect ratio of silicon (Si) nanowire arrays. Different from the direct Ag-loading process, which is normally challenged by the non-uniform coating of Ag, the formation of Ag NPs using such innovative electroless process is no longer to be limited at top nanowire surfaces solely; instead, each Ag+/Si interface can initiate the galvanic reduction of Ag+ ions, thus resulting in the uniform formation of Ag NPs on the entire Si nanowire arrays. In addition, systematic explorations of surface-enhanced Raman scattering (SERS) capability as well as antibacterial activity of the Ag/Si-incorporated nanostructures were performed, and the optimized Ag loadings on Si nanowire-based substrates along with the kinetic investigations were further revealed, which may benefit their practical applications in sensing, medical and biological needs.

  17. The enhanced SERS effect of Ag/ZnO nanoparticles through surface hydrophobic modification

    NASA Astrophysics Data System (ADS)

    Li, Zhenjiang; Zhu, Kaixing; Zhao, Qian; Meng, Alan

    2016-07-01

    Ag/ZnO nanocomposites modified by a mixture of stearic acid (SA) and polyvinylpyrrolidone (PVP) were obtained using a heating reflux method. Fourier transform infrared spectroscopy (FT-IR) suggests that organic SA/PVP was bonded onto the surface of Ag/ZnO nanocrystals, converting the wettability property of the nanostructures from hydrophilic to hydrophobic. The modified Ag/ZnO nanostructures were confirmed as effective Raman substrates, with a 3-fold signal enhancement compared to the ordinary hydrophilic Ag/ZnO substrate for detecting Rh B molecules due to the hydrophobic condensation effect. It is expected that the modified Ag/ZnO nanoparticles have potential for SERS-based rapid detection of molecules.

  18. Silver Nanoparticle-Embedded Thin Silica-Coated Graphene Oxide as an SERS Substrate

    PubMed Central

    Pham, Xuan-Hung; Hahm, Eunil; Kim, Hyung-Mo; Shim, Seongbo; Kim, Tae Han; Jeong, Dae Hong; Lee, Yoon-Sik; Jun, Bong-Hyun

    2016-01-01

    A hybrid of Ag nanoparticle (NP)-embedded thin silica-coated graphene oxide (GO@SiO2@Ag NPs) was prepared as a surface-enhanced Raman scattering (SERS) substrate. A 6 nm layer of silica was successfully coated on the surface of GO by the physical adsorption of sodium silicate, followed by the hydrolysis of 3-mercaptopropyl trimethoxysilane. Ag NPs were introduced onto the thin silica-coated graphene oxide by the reduction of Ag+ to prepare GO@SiO2@Ag NPs. The GO@SiO2@Ag NPs exhibited a 1.8-fold enhanced Raman signal compared to GO without a silica coating. The GO@SiO2@Ag NPs showed a detection limit of 4-mercaptobenzoic acid (4-MBA) at 0.74 μM. PMID:28335304

  19. Fabrication of surface enhanced Raman Scattering (SERS) substrates made from nanoparticle printing inks for detection of biological molecules

    NASA Astrophysics Data System (ADS)

    Figueroa, Manuel Alejandro

    Surface enhanced Raman scattering (SERS) has generated great interest as a surface analytical technique because it can produce amplification factors between 108-1012. Silver and gold are the most widely used components as their size and structure allows for light to induce conduction electrons to oscillate locally within the nanoparticle structure. When a molecule lies in the interparticle space between two nanoparticles, highly detailed vibrational information becomes detectable. The objective of this study is to reproducibly fabricate such an arrangement in a nanoparticle substrate while maintaining stability. In this work, nanoparticle printing inks -- colloidal nanoparticles encapsulated by a stabilizing ligand -- are used as the main component of SERS substrates. The ligand shell is partially removed by controlled heating, which reduces spacing between nanoparticles creating a broad distribution of interparticle distances. Similar to fractal aggregates this arrangement allows localized plasmons to naturally resonate over a broad range of spectral frequencies. Microwave absorption is applied as a non-invasive method to sensitively monitor nanoparticle sintering in order to gauge the substrates' tuning for large amplification factors. The global arrangement of nanoparticles has always been difficult to measure during heating through DC resistivity measurements and surface imaging techniques. Microwave absorption occurs in the weak resistive links formed between particles during sintering due to the microwave losses in loosely coupled particles. By placing the substrate in a microwave cavity, absorption can be monitored globally during heating. The largest SERS amplification factors occur at a stage immediately preceding the largest microwave absorption gains. This provides a useful method for determining a thermal window for heating when optimizing SERS substrates. Finally, these optimized SERS substrates are used to detect hyaluronic acid. This complex molecule

  20. Magnetic gold nanoparticles in SERS-based sandwich immunoassay for antigen detection by well oriented antibodies.

    PubMed

    Baniukevic, Julija; Hakki Boyaci, Ismail; Goktug Bozkurt, Akif; Tamer, Ugur; Ramanavicius, Arunas; Ramanaviciene, Almira

    2013-05-15

    The aim of the study was to develop an indirect, robust and simple in application method for the detection of bovine leukemia virus antigen gp51. Surface-enhanced Raman scattering (SERS) was applied as detection method. Magnetic gold nanoparticles (MNP-Au) modified by antibodies in oriented or random manner were used for the binding of gp51. The high performance liquid chromatography analysis indicated that the best antibody immobilization and antigen capturing efficiency was achieved using fragmented antibodies obtained after reduction of intact antibodies with dithiothreitol. In order to increase efficiency and sensitivity of immunoassay Raman labels consisting of gold nanorods coated by 5-thio-nitrobenzoic acid layer with covalently bounded antibodies have been constructed. The LOD and LOQ of the proposed immunoassay for antigen gp51 detection were found to be 0.95μgmL(-1) and 3.14μgmL(-1), respectively. This immunoassay was successfully applied for the detection of gp51 in milk samples in a rapid, reliable and selective manner. We believe that the proposed SERS-based immunoassay format can be applied for the detection of other proteins.

  1. Orientation of N-benzoyl glycine on silver nanoparticles: SERS and DFT studies

    NASA Astrophysics Data System (ADS)

    Parameswari, A.; Asath, R. Mohamed; Premkumar, R.; Benial, A. Milton Franklin

    2017-05-01

    Surface enhanced Raman scattering (SERS) studies of N-benzoyl glycine (NBG) adsorbed on silver nanoparticles (AgNPs) was studied by experimental and density functional theory (DFT) approach. Single crystals of NBG were prepared using slow evaporation method. The AgNPs were prepared and characterized. The DFT/ B3PW91 method with LanL2DZ basis set was used to optimize the molecular structure of NBG and NBG adsorbed on silver cluster. The calculated and observed vibrational frequencies were assingned on the basis of potential energy distribution calculation. The reduced band gap value was obtained for NBG adsorbed on silver nanoparticles from the frontier molecular orbitals analysis. Natural bond orbital analysis was carried out to inspect the intra-molecular stabilization interactions, which are responsible for the bio activity and nonlinear optical property of the molecule. The spectral analysis was also evidenced that NBG would adsorb tilted orientation on the silver surface over the binding sites such as lone pair electron of N atom in amine group and through phenyl ring π system.

  2. SERS+MEF of the anti-tumoral drug emodin adsorbed on silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Sevilla, Paz; De Llanos, Raquel; Domingo, Concepción; Sánchez-Cortés, Santiago; García-Ramos, José V.

    2010-02-01

    Metal nanostructures are known to amplify the spontaneous emission of fluorescent molecules by resonant coupling to external electromagnetic fields. We have used spectroscopy to characterize the structural properties of emodin molecules, a natural anthraquinone dye, and bovine serum albumin, the most abundant protein in plasma, in the presence of silver nanoparticles. Aggregation of emodin at pH=10 and pH=6 gives rise to SERS and MEF effects in silver colloid. We have obtained MEF spectra at acidic pH=2.9 using two different silver nanostructures. We have also studied the change in the secondary structure of bovine serum albumin adsorbed on metal nanoparticles surface. Circular dichroism, fluorescence emission and fluorescence lifetime measurements indicate an increase in the alfa-helical content of the protein and a change in the environment of the tryptophan residues that bury in the interior of the biomolecule. This variation on the secondary structure could have further influence in the binding of the drug to form transport and regulatory complexes.

  3. Monitoring plasmon coupling and SERS enhancement through in situ nanoparticle spacing modulation.

    PubMed

    Velleman, L; Scarabelli, L; Sikdar, D; Kornyshev, A A; Liz-Marzán, L M; Edel, J B

    2017-09-21

    Self-assembled nanoparticle (NP) arrays at liquid interfaces provide a unique optical response which has opened the door to new tuneable metamaterials for sensing and optical applications. NPs can spontaneously assemble at a liquid-liquid interface, forming an ordered, self-healing, low-defect 2D film. The close proximity of the NPs at the interface results in collective plasmonic modes with a spectral response dependent on the distance between the NPs and induces large field enhancements within the gaps. In this study, we assembled spherical and rod-shaped gold NPs with the aim of improving our understanding of NP assembly processes at liquid interfaces, working towards finely controlling their structure and producing tailored optical and enhanced Raman signals. We systematically tuned the assembly and spacing between NPs through increasing or decreasing the degree of electrostatic screening with the addition of electrolyte or pH adjustment. The in situ modulation of the nanoparticle position on the same sample allowed us to monitor plasmon coupling and the resulting SERS enhancement processes in real time, with sub-nm precision.

  4. Impact of temperature-induced coalescence on SERS properties of Au nanoparticles deposited on GaN nano-columns

    NASA Astrophysics Data System (ADS)

    Dzięcielewski, Igor; Smalc-Koziorowska, Julita; Bańkowska, Małgorzata; Sochacki, Tomasz; Khachapuridze, Alexandr; Weyher, Jan

    2016-08-01

    Nanostructured GaN surfaces sputtered with Au provide very promising and reproducible platforms for surface enhanced Raman scattering (SERS). The enhancement factor (EF) in SERS is expected to depend strongly on the local metal (Au) surface structure (size, distribution and morphology). Herein we show how temperature-induced coalescence followed by recrystallization of Au on GaN nano-columns occurs well below the melting point of gold. This process is reflected in SEM, TEM images and SERS spectra of Au/GaN - bound p-mercaptobenzoic acid (4-MBA), a model Raman scatterer. SERS signals of 4-MBA bound to Au/GaN reach minimum for platforms exposed to t = 350 °C before regaining the intensity when annealed in the range of 450-900 °C. The results have been discussed in the light of the nature of SERS active sites - so called "hot spots" and structure of Au nanoparticles.

  5. SERS detection of R6G based on a novel graphene oxide/silver nanoparticles/silicon pyramid arrays structure.

    PubMed

    Zhang, C; Jiang, S Z; Huo, Y Y; Liu, A H; Xu, S C; Liu, X Y; Sun, Z C; Xu, Y Y; Li, Z; Man, B Y

    2015-09-21

    We present a novel surface-enhanced Raman scattering (SERS) substrate based on graphene oxide/silver nanoparticles/silicon pyramid arrays structure (GO/Ag/PSi). The SERS behaviors are discussed and compared by the detection of R6G. Based on the contrast experiments with PSi, GO/PSi, Ag/PSi and GO/AgA/PSi as SERS substrate, the perfect bio-compatibility, good homogeneity and chemical stability were confirmed. We also calculated the electric field distributions using Finite-difference time-domain (FDTD) analysis to further understand the GO/Ag/PSi structure as a perfect SERS platform. These experimental and theoretical results imply that the GO/Ag/PSi with regular pyramids array is expected to be an effective substrate for label-free sensitive SERS detections in areas of medicine, food safety and biotechnology.

  6. Hybrid organic-inorganic materials based on hydroxyapatite structure

    NASA Astrophysics Data System (ADS)

    Moussa, Sana Ben; Bachouâ, Hassen; Gruselle, Michel; Beaunier, Patricia; Flambard, Alexandrine; Badraoui, Béchir

    2017-04-01

    The present article details the formation of calcium hydroxyapatite synthesized by the hydrothermal way, in presence of glycine or sarcosine. The presence of these amino-acids during the synthetic processes reduces the crystalline growthing through the formation of hybrid organic-inorganic species The crystallite sizes are decreasing and the morphology is modified with the increase of the amino-acid concentration.

  7. Highly efficient SERS substrate for direct detection of explosive TNT using popcorn-shaped gold nanoparticle-functionalized SWCNT hybrid.

    PubMed

    Demeritte, Teresa; Kanchanapally, Rajashekhar; Fan, Zhen; Singh, Anant Kumar; Senapati, Dulal; Dubey, Madan; Zakar, Eugene; Ray, Paresh Chandra

    2012-11-07

    This paper reports for the first time the development of a large-scale SERS substrate from a popcorn-shaped gold nanoparticle-functionalized single walled carbon nanotubes hybrid thin film for the selective and highly sensitive detection of explosive TNT material at a 100 femtomolar (fM) level.

  8. Chemistry of Mesoporous Organosilica in Nanotechnology: Molecularly Organic-Inorganic Hybridization into Frameworks.

    PubMed

    Chen, Yu; Shi, Jianlin

    2016-05-01

    Organic-inorganic hybrid materials aiming to combine the individual advantages of organic and inorganic components while overcoming their intrinsic drawbacks have shown great potential for future applications in broad fields. In particular, the integration of functional organic fragments into the framework of mesoporous silica to fabricate mesoporous organosilica materials has attracted great attention in the scientific community for decades. The development of such mesoporous organosilica materials has shifted from bulk materials to nanosized mesoporous organosilica nanoparticles (designated as MONs, in comparison with traditional mesoporous silica nanoparticles (MSNs)) and corresponding applications in nanoscience and nanotechnology. In this comprehensive review, the state-of-art progress of this important hybrid nanomaterial family is summarized, focusing on the structure/composition-performance relationship of MONs of well-defined morphology, nanostructure, and nanoparticulate dimension. The synthetic strategies and the corresponding mechanisms for the design and construction of MONs with varied morphologies, compositions, nanostructures, and functionalities are overviewed initially. Then, the following part specifically concentrates on their broad spectrum of applications in nanotechnology, mainly in nanomedicine, nanocatalysis, and nanofabrication. Finally, some critical issues, presenting challenges and the future development of MONs regarding the rational synthesis and applications in nanotechnology are summarized and discussed. It is highly expected that such a unique molecularly organic-inorganic nanohybrid family will find practical applications in nanotechnology, and promote the advances of this discipline regarding hybrid chemistry and materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A new heterostructured SERS substrate: free-standing silicon nanowires decorated with graphene-encapsulated gold nanoparticles.

    PubMed

    Li, Yuan; Dykes, John; Gilliam, Todd; Chopra, Nitin

    2017-04-11

    Heterostructures of one-dimensional nanowire supported graphene/plasmonic nanoparticles are promising for future SERS-based chemical sensors. In this paper, we report a novel heterostructured SERS substrate composed of free-standing Si nanowires and surface-decorating Au/graphene nanoparticles. We successfully developed a unique CVD approach for the cost-effective and large-scale growth of free-standing Si nanowires. Au nanoparticles were decorated on the Si nanowires using a galvanic deposition - an annealing approach. This was followed by the selective growth of a multilayer graphene shell on the Au nanoparticles via a xylene-based CVD approach. Discrete dipole approximation simulation was used to understand the plasmonic properties of these Si nanowire-based heterostructures. The results indicate that the incorporation of Au nanoparticles and graphene on Si nanowires has a significant influence on their light absorption and scattering properties. Meanwhile, a strong surface plasmon coupling was observed at the interface regions of different materials (e.g., Si/Au, Au/graphene), introducing multiple co-enhanced "hot spots" on the heterostructures. We found that our new heterostructures have a combined effect of an electromagnetic mechanism and a chemical mechanism for SERS and demonstrate an enhancement factor of 10(6)-10(7).

  10. Single-particle Raman measurements of gold nanoparticles used in surface-enhanced Raman scattering (SERS)-based sandwich immunoassays

    NASA Astrophysics Data System (ADS)

    Park, Hye-Young; Lipert, Robert J.; Porter, Marc D.

    2004-12-01

    The effect of particle size on the intensity of surface-enhanced Raman scattering (SERS) using labeled gold nanoparticles has been investigated. Two sets of experiments were preformed, both of which employed 632.8-nm laser excitation. The first entailed a sandwich immunoassay in which an antibody coupled to a smooth gold substrate selectively captured free-prostate specific antigen (f-PSA) from buffered aqueous solutions. The presence of captured f-PSA was then detected by the response of Raman-labeled immunogold nanoparticles with nominal diameters of 30, 40, 50, 60, or 80 nm. The resulting SERS responses were correlated to particle densities, which were determined by atomic force microscopy, by calculating the average response per particle after accounting for differences in particle surface area. This analysis showed that the magnitude of the SERS response increased with increasing particle size. The second set of experiments examined the response of individual nanoparticles. These experiments differed in that the labeled nanoparticles were coupled to the smooth gold substrate by an amine-terminated thiolate, yielding a much smaller average separation between the particles and substrate. The results revealed that particles with a diameter of ~70 nm exhibited the largest enhancement. The origin of the difference in the two sets of findings, which is attributed to the distance dependence of the plasmon coupling between the nanoparticles and underlying substrate, is briefly discussed.

  11. Cysteamine-modified silver nanoparticle aggregates for quantitative SERS sensing of pentachlorophenol with a portable Raman spectrometer.

    PubMed

    Jiang, Xiaohong; Yang, Min; Meng, Yanjing; Jiang, Wei; Zhan, Jinhua

    2013-08-14

    Cysteamine-modified silver nanoparticle aggregates has been fabricated for pentachlorophenol (PCP) sensing by surface-enhanced Raman spectroscopy (SERS) using a portable Raman spectrometer. The cysteamine monolayers could preconcentrate PCP close to the substrate surface through the electrostatic interaction, which makes the SERS detection of PCP possible. Moreover, the Raman bands of cysteamine could be used as the internal spectral reference in the quantitative analysis. Qualitative detection of PCP was carried out by SERS without any sample pretreatment. Quantitative analysis of PCP was further realized based on the prepared substrate, as the log-log plot of normalized SERS intensity of PCP versus its concentrations exhibits a good linear relationship. The SERS signals collected on 20 randomly selected points show that the relative standard deviation of the normalized Raman intensity is 5.8%, which indicates the substrate had good uniformity. The PCP sensor also shows good long-term stability in the analyte solution. The substrate was cyclic immersed into PCP and methanol solution; after several cycles, the sensor still had good adsorption to PCP, which revealed the sensor has good reusability. Coupling with a portable Raman spectrometer, the cysteamine-modified silver nanoparticle aggregates have the potential to be used for in situ and routine SERS analysis of PCP in environmental samples.

  12. Bio-Conjugated Gold Nanoparticle Based SERS Probe for Ultrasensitive Identification of Mosquito-Borne Viruses Using Raman Fingerprinting.

    PubMed

    Paul, Amber M; Fan, Zhen; Sinha, Sudarson S; Shi, Yongliang; Le, Linda; Bai, Fengwei; Ray, Paresh C

    2015-10-15

    Dengue virus (DENV) and West Nile virus (WNV) are two well-documented mosquito-borne flaviviruses that cause significant health problems worldwide. Driven by this need, we have developed a bio-conjugated gold nanoparticle (AuNP)-based surface enhanced Raman spectroscopy (SERS) probe for the detection of both DENV and WNV. Reported data demonstrate anti-flavivirus 4G2 antibody conjugated gold nanoparticle (GNP) SERS probe can be used as a Raman fingerprint for the ultrasensitive detection of DENV and WNV selectively. Experimental data show that due to the plasmon coupling in nano-assembly, antibody conjugated GNP- based SERS is able to detect as low as 10 plaque-forming units (PFU)/ml of DENV-2 and WNV, which is comparable with the sensitivity of quantitative PCR-based assays. Selectivity of our probe was demonstrated using another mosquito-borne chikungunya virus (CHIKV) as a negative control. Experimental data demonstrate a huge enhancement of SERS intensity is mainly due to the strong electric field enhancement, which has been confirmed by the finite-difference time-domain (FDTD) simulation. Reported FDTD simulation data indicate the SERS enhancement factor can be more than 10(4) times, due to the assembled structure. Reported results suggest that bio-conjugated AuNP-4G2 based SERS probes have great potential to be used to screen viral particles in clinical and research-based laboratories.

  13. Porous Silicon Covered with Silver Nanoparticles as Surface-Enhanced Raman Scattering (SERS) Substrate for Ultra-Low Concentration Detection.

    PubMed

    Kosović, Marin; Balarin, Maja; Ivanda, Mile; Đerek, Vedran; Marciuš, Marijan; Ristić, Mira; Gamulin, Ozren

    2015-12-01

    Microporous and macro-mesoporous silicon templates for surface-enhanced Raman scattering (SERS) substrates were produced by anodization of low doped p-type silicon wafers. By immersion plating in AgNO3, the templates were covered with silver metallic film consisting of different silver nanostructures. Scanning electron microscopy (SEM) micrographs of these SERS substrates showed diverse morphology with significant difference in an average size and size distribution of silver nanoparticles. Ultraviolet-visible-near-infrared (UV-Vis-NIR) reflection spectroscopy showed plasmonic absorption at 398 and 469 nm, which is in accordance with the SEM findings. The activity of the SERS substrates was tested using rhodamine 6G (R6G) dye molecules and 514.5 nm laser excitation. Contrary to the microporous silicon template, the SERS substrate prepared from macro-mesoporous silicon template showed significantly broader size distribution of irregular silver nanoparticles as well as localized surface plasmon resonance closer to excitation laser wavelength. Such silver morphology has high SERS sensitivity that enables ultralow concentration detection of R6G dye molecules up to 10(-15) M. To our knowledge, this is the lowest concentration detected of R6G dye molecules on porous silicon-based SERS substrates, which might even indicate possible single molecule detection.

  14. Tailored SERS substrates obtained with cathodic arc plasma ion implantation of gold nanoparticles into a polymer matrix.

    PubMed

    Ferreira, Jacqueline; Teixeira, Fernanda S; Zanatta, Antonio R; Salvadori, Maria C; Gordon, Reuven; Oliveira, Osvaldo N

    2012-02-14

    This manuscript reports on the fabrication of plasmonic substrates using cathodic arc plasma ion implantation, in addition to their performance as SERS substrates. The technique allows for the incorporation of a wide layer of metallic nanoparticles into a polymer matrix, such as PMMA. The ability to pattern different structures using the PMMA matrix is one of the main advantages of the fabrication method. This opens up new possibilities for obtaining tailored substrates with enhanced performance for SERS and other surface-enhanced spectroscopies, as well as for exploring the basic physics of patterned metal nanostructures. The architecture of the SERS-active substrate was varied using three adsorption strategies for incorporating a laser dye (rhodamine): alongside the nanoparticles into the polymer matrix, during the polymer cure and within nanoholes lithographed on the polymer. As a proof-of-concept, we obtained the SERS spectra of rhodamine for the three types of substrates. The hypothesis of incorporation of rhodamine molecules into the polymer matrix during the cathodic arc plasma ion implantation was supported by FDTD (Finite-Difference Time-Domain) simulations. In the case of arrays of nanoholes, rhodamine molecules could be adsorbed directly on the gold surface, then yielding a well-resolved SERS spectrum for a small amount of analyte owing to the short-range interactions and the large longitudinal field component inside the nanoholes. The results shown here demonstrate that the approach based on ion implantation can be adapted to produce reproducible tailored substrates for SERS and other surface-enhanced spectroscopies.

  15. Adsorption of N-(1-(2-bromophenyl)-2-(2-nitrophenyl)ethyl)-4-methylbenzenesulfonamide on silver nanoparticles: SERS investigation.

    PubMed

    Anuratha, M; Jawahar, A; Umadevi, M; Sathe, V G; Vanelle, P; Terme, T; Khoumeri, O; Meenakumari, V; Milton Franklin Benial, A

    2015-03-05

    SERS provides essential data regarding the interaction of molecules in drugs with DNA. In the present study silver nanoparticles were synthesized using a solution combustion method with urea as fuel. The prepared silver nanoparticles are rod like structure. Surface-enhanced Raman scattering (SERS) of N-(1-2-bromophenyl)-2-(2-nitrophenyl)ethyl)-4-methylbenzenesulfonamide (BrS) adsorbed on the silver nanoparticle was studied. The nRs and Raman spectral analysis reveal that the BrS adsorbed tilted orientation on the silver surface. Vibrational modes of nRs along with HF calculations are also performed to study the HOMO and LUMO behavior and vibrational features of BrS.

  16. Adsorption of N-(1-(2-bromophenyl)-2-(2-nitrophenyl)ethyl)-4-methylbenzenesulfonamide on silver nanoparticles: SERS investigation

    NASA Astrophysics Data System (ADS)

    Anuratha, M.; Jawahar, A.; Umadevi, M.; Sathe, V. G.; Vanelle, P.; Terme, T.; Khoumeri, O.; Meenakumari, V.; Milton Franklin Benial, A.

    2015-03-01

    SERS provides essential data regarding the interaction of molecules in drugs with DNA. In the present study silver nanoparticles were synthesized using a solution combustion method with urea as fuel. The prepared silver nanoparticles are rod like structure. Surface-enhanced Raman scattering (SERS) of N-(1-2-bromophenyl)-2-(2-nitrophenyl)ethyl)-4-methylbenzenesulfonamide (BrS) adsorbed on the silver nanoparticle was studied. The nRs and Raman spectral analysis reveal that the BrS adsorbed tilted orientation on the silver surface. Vibrational modes of nRs along with HF calculations are also performed to study the HOMO and LUMO behavior and vibrational features of BrS.

  17. Fast self-assembly of silver nanoparticle monolayer in hydrophobic environment and its application as SERS substrate

    NASA Astrophysics Data System (ADS)

    Leiterer, Christian; Zopf, David; Seise, Barbara; Jahn, Franka; Weber, Karina; Popp, Jürgen; Cialla-May, Dana; Fritzsche, Wolfgang

    2014-09-01

    We present a method which allows the straightforward wet-chemical synthesis of silver nanoparticles (AgNPs), hydrophobic coating assembling into monolayer, and their utilization as substrates for surface-enhanced Raman spectroscopy (SERS). In order to fabricate the SERS-active substrates, AgNPs were synthesized in water by chemical reduction of Ag+, coated with a hydrophobic shell (dodecanethiol), transferred to a non-polar solvent, and finally assembled through precipitation into a SERS-active self-assembled monolayer (SAM). Simple approaches for concentration and purification of the coated AgNPs are shown. The synthesized particles and SAMs were characterized by transmission electron microscopy, optical imaging, and spectroscopic measurements. This manuscript can be used as a do-it-yourself (DIY) tutorial which allows making SAMs from coated AgNPs (<15 nm) in every laboratory within less than 1 h and their utilization as potential low-cost SERS substrates (movie 1-4).

  18. Silica Encapsulated Gold Nanoparticles as SERS Labels for the Detection of Lymphoma B-Cells in Tissue Sections

    NASA Astrophysics Data System (ADS)

    Al-Faouri, Tamara

    The surface of silica encapsulated gold nanoparticles with trans-1,2-bis (4-pyridyl) ethylene Raman active dye were utilized as SERS labels to target CD20 surface protein on lymphoma B-cells in human tissue sections with CLL or FL. SERS labels were functionalized with various antibody linkers including carboxylic, aldehyde, and heterobifunctional PEG chains with an NHS end, to permit them to bind to tissue section samples. NP samples and tissue sections were characterized through UV-Vis spectroscopy, TEM, XPS, Zeta potential measurements, Dark Field microscopy, Raman spectroscopy, NMR, and AFM. The number of SERS labels present on a tissue sample was estimated using dark field images and a particle counting software. It was found that the heterobifunctional PEG chains linker provided the most specific binding of SERS labels with an estimated NP count of 1.33x106 NPs on the whole tissue and produced the highest Raman scatter intensity of approximately 48600 counts.

  19. Iodide-induced organothiol desorption and photochemical reaction, gold nanoparticle (AuNP) fusion, and SERS signal reduction in organothiol-containing AuNP aggregates

    USDA-ARS?s Scientific Manuscript database

    Gold nanoparticles (AuNPs) have been used extensively as surface-enhanced Raman spectroscopic (SERS) substrates for their large SERS enhancements and widely believed chemical stability. Presented is the finding that iodide can rapidly reduce the SERS intensity of the ligands, including organothiols ...

  20. Quantitative molecular phenotyping with topically applied SERS nanoparticles for intraoperative guidance of breast cancer lumpectomy

    PubMed Central

    Wang, Yu; Kang, Soyoung; Khan, Altaz; Ruttner, Gabriel; Leigh, Steven Y.; Murray, Melissa; Abeytunge, Sanjee; Peterson, Gary; Rajadhyaksha, Milind; Dintzis, Suzanne; Javid, Sara; Liu, Jonathan T.C.

    2016-01-01

    There is a need to image excised tissues during tumor-resection procedures in order to identify residual tumors at the margins and to guide their complete removal. The imaging of dysregulated cell-surface receptors is a potential means of identifying the presence of diseases with high sensitivity and specificity. However, due to heterogeneities in the expression of protein biomarkers in tumors, molecular-imaging technologies should ideally be capable of visualizing a multiplexed panel of cancer biomarkers. Here, we demonstrate that the topical application and quantification of a multiplexed cocktail of receptor-targeted surface-enhanced Raman scattering (SERS) nanoparticles (NPs) enables rapid quantitative molecular phenotyping (QMP) of the surface of freshly excised tissues to determine the presence of disease. In order to mitigate the ambiguity due to nonspecific sources of contrast such as off-target binding or uneven delivery, a ratiometric method is employed to quantify the specific vs. nonspecific binding of the multiplexed NPs. Validation experiments with human tumor cell lines, fresh human tumor xenografts in mice, and fresh human breast specimens demonstrate that QMP imaging of excised tissues agrees with flow cytometry and immunohistochemistry, and that this technique may be achieved in less than 15 minutes for potential intraoperative use in guiding breast-conserving surgeries. PMID:26878888

  1. Quantitative molecular phenotyping with topically applied SERS nanoparticles for intraoperative guidance of breast cancer lumpectomy

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Kang, Soyoung; Khan, Altaz; Ruttner, Gabriel; Leigh, Steven Y.; Murray, Melissa; Abeytunge, Sanjee; Peterson, Gary; Rajadhyaksha, Milind; Dintzis, Suzanne; Javid, Sara; Liu, Jonathan T. C.

    2016-02-01

    There is a need to image excised tissues during tumor-resection procedures in order to identify residual tumors at the margins and to guide their complete removal. The imaging of dysregulated cell-surface receptors is a potential means of identifying the presence of diseases with high sensitivity and specificity. However, due to heterogeneities in the expression of protein biomarkers in tumors, molecular-imaging technologies should ideally be capable of visualizing a multiplexed panel of cancer biomarkers. Here, we demonstrate that the topical application and quantification of a multiplexed cocktail of receptor-targeted surface-enhanced Raman scattering (SERS) nanoparticles (NPs) enables rapid quantitative molecular phenotyping (QMP) of the surface of freshly excised tissues to determine the presence of disease. In order to mitigate the ambiguity due to nonspecific sources of contrast such as off-target binding or uneven delivery, a ratiometric method is employed to quantify the specific vs. nonspecific binding of the multiplexed NPs. Validation experiments with human tumor cell lines, fresh human tumor xenografts in mice, and fresh human breast specimens demonstrate that QMP imaging of excised tissues agrees with flow cytometry and immunohistochemistry, and that this technique may be achieved in less than 15 minutes for potential intraoperative use in guiding breast-conserving surgeries.

  2. Heterogeneous Catalysis of Polyoxometalate Based Organic-Inorganic Hybrids.

    PubMed

    Ren, Yuanhang; Wang, Meiyin; Chen, Xueying; Yue, Bin; He, Heyong

    2015-03-31

    Organic-inorganic hybrid polyoxometalate (POM) compounds are a subset of materials with unique structures and physical/chemical properties. The combination of metal-organic coordination complexes with classical POMs not only provides a powerful way to gain multifarious new compounds but also affords a new method to modify and functionalize POMs. In parallel with the many reports on the synthesis and structure of new hybrid POM compounds, the application of these compounds for heterogeneous catalysis has also attracted considerable attention. The hybrid POM compounds show noteworthy catalytic performance in acid, oxidation, and even in asymmetric catalytic reactions. This review summarizes the design and synthesis of organic-inorganic hybrid POM compounds and particularly highlights their recent progress in heterogeneous catalysis.

  3. Hydrogen Bonding and Stability of Hybrid Organic-Inorganic Perovskites.

    PubMed

    El-Mellouhi, Fedwa; Marzouk, Asma; Bentria, El Tayeb; Rashkeev, Sergey N; Kais, Sabre; Alharbi, Fahhad H

    2016-09-22

    In the past few years, the efficiency of solar cells based on hybrid organic-inorganic perovskites has exceeded the level needed for commercialization. However, existing perovskites solar cells (PSCs) suffer from several intrinsic instabilities, which prevent them from reaching industrial maturity, and stabilizing PSCs has become a critically important problem. Here we propose to stabilize PSCs chemically by strengthening the interactions between the organic cation and inorganic anion of the perovskite framework. In particular, we show that replacing the methylammonium cation with alternative protonated cations allows an increase in the stability of the perovskite by forming strong hydrogen bonds with the halide anions. This interaction also provides opportunities for tuning the electronic states near the bandgap. These mechanisms should have a universal character in different hybrid organic-inorganic framework materials that are widely used. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Organic-inorganic hybrid polymer-encapsulated magnetic nanobead catalysts.

    PubMed

    Arai, Takayoshi; Sato, Toru; Kanoh, Hirofumi; Kaneko, Katsumi; Oguma, Koichi; Yanagisawa, Akira

    2008-01-01

    A new strategy for the encapsulation of magnetic nanobeads was developed by using the in situ self-assembly of an organic-inorganic hybrid polymer. The hybrid polymer of {[Cu(bpy)(BF(4))(2)(H(2)O)(2)](bpy)}(n) (bpy=4,4'-bipyridine) was constructed on the surface of amino-functionalized magnetic beads and the resulting hybrid-polymer-encapsulated beads were utilized as catalysts for the oxidation of silyl enolates to provide the corresponding alpha-hydroxy carbonyl compounds in high yield. After the completion of the reaction, the catalyst was readily recovered by magnetic separation and the recovered catalyst could be reused several times. Because the current method did not require complicated procedures for incorporating the catalyst onto the magnetic beads, the preparation and the application of various other types of organic-inorganic hybrid-polymer-coated magnetic beads could be possible.

  5. The characteristic AgcoreAushell nanoparticles as SERS substrates in detecting dopamine molecules at various pH ranges

    PubMed Central

    Bu, Yanru; Lee, Sang-Wha

    2015-01-01

    AgcoreAushell nanoparticles (NPs) are a promising surface-enhanced Raman scattering (SERS) substrate, which can offer a high enhancement factor through the combined effect of the high SERS activity of the Ag core and the biocompatibility of the Au shell. In this study, AgcoreAushell NPs were examined as SERS substrates for the sensitive detection of dopamine (DA) molecules in an aqueous solution. The SERS activity of the AgcoreAushell NPs was strongly dependent on the pH of the solution. When the pH of the solution was acidic (pH <5) or basic (pH >9), the AgcoreAushell NPs exhibited negligible SERS activity toward the DA molecules, due to the weakened interactions (or repulsive forces) between the DA molecules and the core–shell NPs. On the other hand, the AgcoreAushell NPs exhibited a high SERS activity in the intermediate pH ranges (pH 7–9), due to the molecular bridging effect of DA molecules, which allows probe molecules to be located at the interstitial junctions (so-called hot spots) between the core–shell NPs. The results of this study highlight the importance of probe-induced clustering of core–shell NPs in the SERS measurements at physiological pH. PMID:26345418

  6. Ag-nanoparticle-decorated porous ZnO-nanosheets grafted on a carbon fiber cloth as effective SERS substrates.

    PubMed

    Wang, Zhiwei; Meng, Guowen; Huang, Zhulin; Li, Zhongbo; Zhou, Qitao

    2014-12-21

    We report on the large-scale synthesis of Ag-nanoparticle (Ag-NP) decorated ZnO-mesoporous-nanosheets (NSs) grafted on a flexible carbon fiber cloth (CFC), as sensitive and reproducible surface enhanced Raman scattering (SERS) substrates with excellent flexibility. The composite SERS-substrates are achieved by a combination of atomic layer deposition of ZnO-seeds on each fiber of the CFC (denoted as ZnO-seeds@CFC), chemical bath deposition and subsequent pyrolysis for the creation of ZnO-mesoporous-NSs grafted on ZnO-seeds@CFC, and ion-sputtering of Ag-NPs on the ZnO-mesoporous-NSs. As abundant SERS "hot spots" are generated from the electromagnetic coupling of the densely distributed Ag-NPs, and the semiconducting ZnO-mesoporous-NSs also have chemical supporting enhancement and distinct molecule adsorbing abilities, the composite SERS-substrates demonstrate high SERS-sensitivity with good signal reproducibility. As a trial for potential applications, the composite SERS-substrates were used to identify pesticides and highly toxic polychlorinated biphenyls (PCBs), and low concentrations down to 10(-7) M for methyl parathion and 5 × 10(-6) M for PCB-77 were reached, respectively, showing promising potential for the SERS-based rapid detection of toxic organic pollutants in the environment.

  7. Near-infrared sensitive organic-inorganic photorefractive device

    NASA Astrophysics Data System (ADS)

    Marinova, Vera; Liu, Ren-Chung; Lin, Shiuan-Huei; Chen, Ming-Syuan; Lin, Yi-Hsin; Hsu, Ken-Yuh

    2016-10-01

    Organic-inorganic hybrid structure, assembled by Rh-doped Bi12TiO20 crystal and liquid crystal (LC) layer, operating at near-infrared range is proposed and demonstrated. Due to the photorefractive properties of inorganic substrate, light illumination caused a space charge field which acts as a driving force for LC molecules re-alignment and subsequent refractive index modulation. All optically controlled phase retardation ability has been demonstrated supporting possibilities for further infrared applications.

  8. Vanadium-oxo based hybrid organic-inorganic copolymers

    SciTech Connect

    Campero, A.; Soto, A.M.; Maquet, J.; Sanchez, C.

    1996-12-31

    The authors describe the synthesis and characterization of hybrid organic-inorganic copolymer materials formed by the reaction of the transition metal alkoxide VO(OAm{sup t}){sub 3} with the chelating monomer ligand acetoacetoxyethylmethacrylate (AAEM). By the simultaneous induction of the organic and inorganic polymerization reactions, covalent bonds are formed between both types of interpenetrating components. The organic chelating moiety of AAEM is linked through its {beta}-diketo function to the vanadium-oxo species.

  9. SERS study of surface plasmon resonance induced carrier movement in Au@Cu2O core-shell nanoparticles.

    PubMed

    Chen, Lei; Zhang, Fan; Deng, Xin-Yu; Xue, Xiangxin; Wang, Li; Sun, Yantao; Feng, Jing-Dong; Zhang, Yongjun; Wang, Yaxin; Jung, Young Mee

    2018-01-15

    A plasmon induced carrier movement enhanced mechanism of surface-enhanced Raman scattering (SERS) was investigated using a charge-transfer (CT) enhancement mechanism. Here, we designed a strategy to study SERS in Au@Cu2O nanoshell nanoparticles with different shell thicknesses. Among the plasmonically coupled nanostructures, Au spheres with Cu2O shells have been of special interest due to their ultrastrong electromagnetic fields and controllable carrier transfer properties, which are useful for SERS. Au@Cu2O nanoshell nanoparticles (NPs) with shell thicknesses of 48-56nm are synthesized that exhibit high SERS activity. This high activity originates from plasmonic-induced carrier transfer from Au@Cu2O to 4-mercaptobenzoic acid (MBA). The CT transition from the valence band (VB) of Cu2O to the second excited π-π* transition of MBA, and is of b2 electronic symmetry, which was enhanced significantly. The Herzberg-Teller selection rules were employed to predict the observed enhanced b2 symmetry modes. The system constructed in this study combines the long-range electromagnetic effect of Au NPs, localized surface plasmon resonance (LSPR) of the Au@Cu2O nanoshell, and the CT contribution to assist in understanding the SERS mechanism based on LSPR-induced carrier movement in metal/semiconductor nanocomposites. Copyright © 2017. Published by Elsevier B.V.

  10. Organic-inorganic composites designed for biomedical applications.

    PubMed

    Miyazaki, Toshiki; Ishikawa, Kunio; Shirosaki, Yuki; Ohtsuki, Chikara

    2013-01-01

    Several varieties of ceramics, such as Bioglass-type glasses, sintered hydroxyapatite and glass-ceramic A-W, exhibit specific biological affinity, i.e., direct bonding to surrounding bone, when implanted in bony defects. These bone-bonding ceramics are called bioactive ceramics and are utilized as important bone substitutes in the medical field. However, there is a limitation to their clinical applications because of their inappropriate mechanical properties. Natural bone takes a kind of organic-inorganic composite, where apatite nanocrystals are precipitated on collagen fibers. Therefore, problems with the bioactive ceramics can be solved by material design based on the composites. In this paper, current research topics on the development of bioactive organic-inorganic composites inspired by actual bone microstructure have been reviewed in correlation with preparation methods and various properties. Several kinds of inorganic components have been found to exhibit bioactivity in the body environment. Combination of the inorganic components with various organic polymers enables the development of bioactive organic-inorganic composites. In addition, novel biomedical applications of the composites to drug delivery systems, scaffolds for tissue regeneration and injectable biomaterials are available by combining drugs or biological molecules with appropriate control of its microstructure.

  11. Organic/Inorganic Complex Pigments: Ancient Colors Maya Blue

    SciTech Connect

    Polette-Niewold, L.A.; Manciu, F.S.; Torres, B.; Alvarado, M.; Jr.; Chianelli, R.R.

    2009-06-04

    Maya Blue is an ancient blue pigment composed of palygorskite clay and indigo. It was used by the ancient Maya and provides a dramatic background for some of the most impressive murals throughout Mesoamerica. Despite exposure to acids, alkalis, and chemical solvents, the color of the Maya Blue pigment remains unaltered. The chemical interaction between palygorskite and indigo form an organic/inorganic complex with the carbonyl oxygen of the indigo bound to a surface Al{sup 3+} in the Si-O lattice. In addition indigo will undergo an oxidation to dehydroindigo during preparation. The dehydro-indigo molecule forms a similar but stronger complex with the Al{sup 3+}. Thus, Maya Blue varies in color due to the mixed indigo/dehydroindigo complex. The above conclusions are the result of application of multiple techniques (X-ray diffraction, differential thermal analysis/thermal gravimetric analysis, high resolution transmission electron microscopy, scanning electron microscopy, infrared and Raman spectroscopy) to the characterization of the organic/inorganic complex. A picture of the bonding of the organic molecule to the palygorskite surface forming a surface complex is developed and supported by the results of density functional theory calculations. We also report that other organic molecules such as thioindigo form similar organic/inorganic complexes thus, opening an entirely new class of complex materials for future applications.

  12. Fabrication and SERS performance of silver-nanoparticle-decorated Si/ZnO nanotrees in ordered arrays.

    PubMed

    Cheng, Chuanwei; Yan, Bin; Wong, She Mein; Li, Xianglin; Zhou, Weiwei; Yu, Ting; Shen, Zexiang; Yu, Hongyu; Fan, Hong Jin

    2010-07-01

    Highly ordered treelike Si/ZnO hierarchical nanostructures are successfully prepared in a large scale by combining two common techniques, viz., photolithography-assisted wafer-scale fabrication of Si nanopillars and bottom-up hydrothermal growth of ZnO nanorods. Silver nanoparticles are decorated onto the nanotrees by photochemical reduction and deposition. The Si/ZnO/Ag hybrid nanotrees are employed as SERS-active substrates, which exhibit good performance in terms of high sensitivity and good reproducibility. In addition to the SERS application, such ordered Si/ZnO arrays might also find potential applications in light-emitting diodes and solar cells.

  13. Importance of nanoparticle size in colorimetric and SERS-based multimodal trace detection of Ni(II) ions with functional gold nanoparticles.

    PubMed

    Krpetić, Zeljka; Guerrini, Luca; Larmour, Iain A; Reglinski, John; Faulds, Karen; Graham, Duncan

    2012-03-12

    Colorimetric detection of analytes using gold nanoparticles along with surface-enhanced Raman spectroscopy (SERS) are areas of intense research activity since they both offer sensing of very low concentrations of target species. Multimodal detection promotes the simultaneous detection of a sample by a combination of different techniques; consequently, surface chemistry design in the development of multimodal nanosensors is important for rapid and sensitive evaluation of the analytes by diverse analytical methods. Herein it is shown that nanoparticle size plays an important role in the design of functional nanoparticles for colorimetric and SERS-based sensing applications, allowing controlled nanoparticle assembly and tunable sensor response. The design and preparation of robust nanoparticle systems and their assembly is reported for trace detection of Ni(II) ions as a model system in an aqueous solution. The combination of covalently attached nitrilotriacetic acid moieties along with the L-carnosine dipeptide on the nanoparticle surface represents a highly sensitive platform for rapid and selective detection of Ni(II) ions. This systematic study demonstrates that significantly lower detection limits can be achieved by finely tuning the assembly of gold nanoparticles of different core sizes. The results clearly demonstrate the feasibility and usefulness of a multimodal approach.

  14. SERS Properties of Different Sized and Shaped Gold Nanoparticles Biosynthesized under Different Environmental Conditions by Neurospora crassa Extract

    PubMed Central

    Quester, Katrin; Avalos-Borja, Miguel; Vilchis-Nestor, Alfredo Rafael; Camacho-López, Marco Antonio; Castro-Longoria, Ernestina

    2013-01-01

    Surface-enhanced Raman scattering (SERS) is a surface-sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces. It is known that metal nanoparticles, especially gold and silver nanoparticles, exhibit great SERS properties, which make them very attractive for the development of biosensors and biocatalysts. On the other hand, the development of ecofriendly methods for the synthesis of metallic nanostructures has become the focus of research in several countries, and many microorganisms and plants have already been used to biosynthesize metallic nanostructures. However, the majority of these are pathogenic to plants or humans. Here, we report gold nanoparticles with good SERS properties, biosynthesized by Neurospora crassa extract under different environmental conditions, increasing Raman signals up to 40 times using methylene blue as a target molecule. Incubation of tetrachloroauric acid solution with the fungal extract at 60°C and a pH value of a) 3, b) 5.5, and c) 10 resulted in the formation of gold nanoparticles of a) different shapes like triangles, hexagons, pentagons etc. in a broad size range of about 10-200 nm, b) mostly quasi-spheres with some different shapes in a main size range of 6-23 nm, and c) only quasi-spheres of 3-12 nm. Analyses included TEM, HRTEM, and EDS in order to corroborate the shape and the elemental character of the gold nanoparticles, respectively. The results presented here show that these ‘green’ synthesized gold nanoparticles might have potential applicability in the field of biological sensing. PMID:24130891

  15. High Temperature Resistant Organic/Inorganic Hybrid Polymers: An Architectural Study

    DTIC Science & Technology

    2007-04-18

    DATES COVERED July 10 2003 – January 09 2007 4. TITLE AND SUBTITLE High Temperature Resistant Organic/ Inorganic Hybrid Polymers: An...Supramolecular Chemistry, High Temperature Materials, Organic Inorganic Hybrid Materials, Sensors 15. NUMBER OF PAGES 16...298-102 Enclosure 1 2 High Temperature Resistant Organic/ Inorganic Hybrid Polymers: An Architectural Study DAAD19-03-1-0208 PIs Stuart

  16. Controllable synthesis of organic-inorganic hybrid MoOx/polyaniline nanowires and nanotubes.

    PubMed

    Wang, Sinong; Gao, Qingsheng; Zhang, Yahong; Gao, Jing; Sun, Xuhui; Tang, Yi

    2011-02-01

    A novel chemical oxidative polymerization approach has been proposed for the controllable preparation of organic-inorganic hybrid MoO(x)/polyaniline (PANI) nanocomposites based on the nanowire precursor of Mo(3)O(10)(C(6)H(8)N)(2)·2H(2)O with sub-nanometer periodic structures. The nanotubes, nanowires, and rambutan-like nanoparticles of MoO(x)/PANI were successfully obtained through simply modulating the pH values to 2.5-3.5, ≈2.0 and ≈1.0, respectively. Through systematic physicochemical characterization, such as scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and so forth, the composition and structure of MoO(x)/PANI hybrid nanocomposites are well confirmed. It is found that the nanowire morphology of the precursor is the key to achieve the one-dimensional (1D) structures of final products. A new polymerization-dissolution mechanism is proposed to explain the formation of such products with different morphologies, in which the match between polymerization and dissolution processes of the precursor plays the important role. This approach will find a new way to controllably prepare various organic-inorganic hybrid 1D nanomaterials especially for polymer-hybrid nanostructures.

  17. Preparation of chitosan/nano hydroxyapatite organic-inorganic hybrid microspheres for bone repair.

    PubMed

    Chen, Jingdi; Pan, Panpan; Zhang, Yujue; Zhong, Shengnan; Zhang, Qiqing

    2015-10-01

    In this work, we encapsulated icariin (ICA) into chitosan (CS)/nano hydroxyapatite (nHAP) composite microspheres to form organic-inorganic hybrid microspheres for drug delivery carrier. The composition and morphology of composite microspheres were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry- thermogravimetric analysis (DSC-TGA). Moreover, we further studied the performance of swelling properties, degradation properties and drug release behavior of the microspheres. ICA, the extract of traditional Chinese medicine-epimedium, was combined to study drug release properties of the microspheres. ICA loaded microspheres take on a sustained release behavior, which can be not only ascribed to electrostatic interaction between reactive negative hydroxyl (OH) of ICA and positive amine groups (NH₂) of CS, but also depended on the homogeneous dispersion of HAP nanoparticles inside CS organic matrix. In addition, the adhesion and morphology of osteoblasts were detected by inverted fluorescence microscopy. The biocompatibility of CS/nHAP/ICA microspheres was evaluated by the MTT cytotoxicity assay, Hoechst 33258 and PI fluorescence staining. These studies demonstrate that composite microspheres provide a suitable microenvironment for osteoblast attachment and proliferation. It can be speculated that the ICA loaded CS-based organic-inorganic hybrid microspheres might have potential applications in drug delivery systems.

  18. Biosynthesized silver nanoparticles performing as biogenic SERS-nanotags for investigation of C26 colon carcinoma cells.

    PubMed

    Potara, Monica; Bawaskar, Manisha; Simon, Timea; Gaikwad, Swapnil; Licarete, Emilia; Ingle, Avinash; Banciu, Manuela; Vulpoi, Adriana; Astilean, Simion; Rai, Mahendra

    2015-09-01

    In this work, two classes of silver nanoparticles (AgNPs) were biosynthesized with the goal to assess their reliability in vitro as surface-enhanced Raman scattering (SERS) nanotags. Mycosynthesized silver nanoparticles (MAgNPs) and phytosynthesized silver nanoparticles (PAgNPs) were produced through environmentally friendly procedures by reduction of silver nitrate with Fusarium oxysporum cell filtrate and Azadirachta indica extract, respectively. Two cell lines, namely C26 murine colon carcinoma cells as example of cancer cells and human immortalized keratinocyte cells (HaCaT) as representative of healthy cell line, were selected for in vitro investigation. The in vitro toxicity studies show that M(P)AgNPs present lower cytotoxic effect on both cell lines as compared with standard citrate coated AgNPs. The internalization of M(P)AgNPs by colon carcinoma cells and structural alterations induced in the morphology of treated cells were analyzed by dark-field (DF) and differential interference contrast (DIC) microscopy, respectively. The most informative data about the cellular uptake and tracking potential of M(P)AgNPs were provided by scanning Confocal Raman Microscopy (CRM) and multivariate K-means cluster analysis of collected Raman spectra. The analysis reveals the subcellular components and the localization of AgNPs inside the cell via the intrinsic SERS signature of biogenic coating material. The use of unique biological material to perform synthesis, stability, biocompatibility and SERS tagging is relevant both from the point of view of encoding nanoparticles with Raman reporters and further applications in cell investigation via Raman/SERS imaging.

  19. Polyethylene glycol gold-nanoparticles: Facile nanostructuration of doxorubicin and its complex with DNA molecules for SERS detection

    NASA Astrophysics Data System (ADS)

    Spadavecchia, Jolanda; Perumal, Ramesh; Casale, Sandra; Krafft, Jean-Marc; Methivier, Christophe; Pradier, Claire-Marie

    2016-03-01

    We report the synthesis of dicarboxylic acid-terminated polyethylene-glycol (PEG)-gold nanoparticles by a simple one-step method, and their further use to form nanostructured surfaces for biomolecule immobilization. The synthesized nano-scale particles were conjugated with probe/target oligonucleotides in order to evaluate intercalation phenomenon in the presence of doxorubicin drug via surface enhanced Raman spectroscopy (SERS) analysis.

  20. Highly sensitive SERS detection and quantification of sialic acid on single cell using photonic-crystal fiber with gold nanoparticles.

    PubMed

    Gong, Tianxun; Cui, Ying; Goh, Douglas; Voon, Kong Kien; Shum, Perry Ping; Humbert, Georges; Auguste, Jean-Louis; Dinh, Xuan-Quyen; Yong, Ken-Tye; Olivo, Malini

    2015-02-15

    An ultrasensitive surface enhanced Raman spectroscopy (SERS) based sensing platform was developed to detect the mean sialic acid level on the surface of single cell with sensitivity as low as 2 fmol. This platform adopted the use of an interference-free Raman tag, 4-(dihydroxyborophenyl) acetylene (DBA), which selectively binds to sialic acid on the cell membrane. By loading the side channel of a photonic crystal fiber with a mixture of gold nanoparticles and DBA-tagged HeLa cell, and subsequently propagating laser light through the central solid core, strong SERS signal was obtained. This SERS technique achieved accurate detection and quantification of concentration of sialic acid on a single cell, surpassing previously reported methods that required more than 10(5) cells. Moreover, this platform can be developed into a clinical diagnostic tool to potentially analyze sialic acid-related diseases such as tumor malignancy and metastasis in real-time.

  1. A study of the depth and size of concave cube Au nanoparticles as highly sensitive SERS probes

    NASA Astrophysics Data System (ADS)

    Romo-Herrera, J. M.; González, A. L.; Guerrini, L.; Castiello, F. R.; Alonso-Nuñez, G.; Contreras, O. E.; Alvarez-Puebla, R. A.

    2016-03-01

    High and uniform near fields are localized at the eight similar sharp corners of cubic gold nanoparticles. Moreover, by introducing concavity in the particle lateral planes, such field intensities can be further increased and tuned in the near infrared region without altering the overall size of the nanoparticles. Herein, we perform a thorough investigation of the morphological, crystallographic and plasmonic properties of concave gold nanocubes (GNCs) in the sub-70 nm size range, for their potential application as highly efficient SERS substrates in size-limiting cases. Theoretical calculations indicate that the highest increment of the near-field is located at the eight sharp tips and, interestingly, a medium near-field increment is also activated over the volume next to the concave surface. Remarkably, the plasmonic response of the concave cubic morphology showed great sensitivity to the concavity degree. Experimental SERS analysis nicely matches the outcome of the theoretical model, confirming that medium-sized concave GNCs (35 nm side length) possess the highest SERS activity upon excitation with a 633 nm laser, whereas larger 61 nm side concave GNCs dominate the optical response at 785 nm. Due to their size-intensity trade off, we envision that such small concave gold nanocubes can provide a highly active and efficient SERS platform for size-limiting applications, especially when near infrared excitations are required.High and uniform near fields are localized at the eight similar sharp corners of cubic gold nanoparticles. Moreover, by introducing concavity in the particle lateral planes, such field intensities can be further increased and tuned in the near infrared region without altering the overall size of the nanoparticles. Herein, we perform a thorough investigation of the morphological, crystallographic and plasmonic properties of concave gold nanocubes (GNCs) in the sub-70 nm size range, for their potential application as highly efficient SERS

  2. SERS investigations on orientation of 2-bromo-3-methyl-1,4-dimethoxy-9,10-anthraquinone on silver nanoparticles.

    PubMed

    Anuratha, M; Jawahar, A; Umadevi, M; Sathe, V G; Vanelle, P; Terme, T; Khoumeri, O; Meenakumari, V; Milton Franklin Benial, A

    2015-01-01

    Silver nanoparticles (Ag NPs) were prepared by solution combustion method with urea as fuel. Silver nanoparticles were characterized by UV-visible spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Surface-enhanced Raman scattering (SERS) of 2-bromo-3-methyl-1,4-dimethoxy-9,10-anthraquinone (BMDMAQ) adsorbed on silver nanoparticles was investigated. The orientation of BMDMAQ on silver nanoparticles was inferred from nRs and SERS spectral features. Density functional theory (DFT) calculation was also performed to study the theoretical performance. The observed spectral features such as the high intensity of C-H out-of-plane bending mode and ring C-C stretching mode revealed that BMDMAQ adsorbed on silver surface through 'stand-on' orientation. Anthraquinone (AQ) derivatives have wide biomedical application which includes laxatives, antimalarials and antineoplastics used in the treatment of cancer. This present study would help to identify the interaction of drug molecules with DNA. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Orientation of N-(1-(2-chlorophenyl)-2-(2-nitrophenyl)ethyl)-4-methylbenzenesulfonamide on silver nanoparticles: SERS studies.

    PubMed

    Anuratha, M; Jawahar, A; Umadevi, M; Sathe, V G; Vanelle, P; Terme, T; Meenakumari, V; Milton Franklin Benial, A

    2014-10-15

    In the present study, the silver nanoparticles were synthesized using a solution combustion method with urea as fuel. The prepared silver nanoparticles show an FCC crystalline structure with particle size of 59nm. FESEM image shows the prepared silver is a rod like structure. The surface-enhanced Raman scattering (SERS) spectrum indicates that the N-(1-(2-chlorophenyl)-2-(2-nitrophenyl)ethyl)-4-methylbenzenesulfonamide (CS) molecule adsorbed on the silver nanoparticles. The spectral analysis reveals that the sulfonamide is adsorbed by tilted orientation on the silver surface. The Hatree Fock calculations were also performed to predict the vibrational motions of CS. This present investigation has been a model system to deduce the interaction of drugs with DNA. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Automated process for solvent separation of organic/inorganic substance

    DOEpatents

    Schweighardt, Frank K.

    1986-01-01

    There is described an automated process for the solvent separation of organic/inorganic substances that operates continuously and unattended and eliminates potential errors resulting from subjectivity and the aging of the sample during analysis. In the process, metered amounts of one or more solvents are passed sequentially through a filter containing the sample under the direction of a microprocessor control apparatus. The mixture in the filter is agitated by ultrasonic cavitation for a timed period and the filtrate is collected. The filtrate of each solvent extraction is collected individually and the residue on the filter element is collected to complete the extraction process.

  5. Automated process for solvent separation of organic/inorganic substance

    DOEpatents

    Schweighardt, F.K.

    1986-07-29

    There is described an automated process for the solvent separation of organic/inorganic substances that operates continuously and unattended and eliminates potential errors resulting from subjectivity and the aging of the sample during analysis. In the process, metered amounts of one or more solvents are passed sequentially through a filter containing the sample under the direction of a microprocessor control apparatus. The mixture in the filter is agitated by ultrasonic cavitation for a timed period and the filtrate is collected. The filtrate of each solvent extraction is collected individually and the residue on the filter element is collected to complete the extraction process. 4 figs.

  6. Organic-inorganic hybrid glass: non-linear optical properties

    NASA Astrophysics Data System (ADS)

    Domínguez Cruz, R.; Mendez-Perez, A.; Romero Galván, G.; Mendoza-Panduro, M.; Trejo-Duran, M.; Alvarado-Mendez, E.; Estudillo-Ayala, J. M.; Rojas-Laguna, R.; Martínez-Richa, A.; Castano, V. M.

    2008-04-01

    In this paper we report the preliminary results about the optical characterization of a new kind of organic-inorganic hybrid glass named 4-((5-dichloromethylsily1)-penty)oxy-cyanobenzene (DCN) synthesized by sol-gel process. We obtain the sign and magnitude of the sample by the Z-scan technique using a low power He-Ne laser at 632 nm in CW operation. The experimental data show that the DNC glass has a negative Kerr optical non-linearity and is estimated a nonlinear coefficient as Δn˜10-6.

  7. Preparations and Characterizations of Luminescent Two Dimensional Organic-inorganic Perovskite Semiconductors

    PubMed Central

    Zhang, Sanjun; Audebert, Pierre; Wei, Yi; Al Choueiry, Antoine; Lanty, Gaëtan; Bréhier, Antoine; Galmiche, Laurent; Clavier, Gilles; Boissière, Cédric; Lauret, Jean-Sébastien; Deleporte, Emmanuelle

    2010-01-01

    This article reviews the synthesis, structural and optical characterizations of some novel luminescent two dimensional organic-inorganic perovskite (2DOIP) semiconductors. These 2DOIP semiconductors show a self-assembled nano-layered structure, having the electronic structure of multi-quantum wells. 2DOIP thin layers and nanoparticles have been prepared through different methods. The structures of the 2DOIP semiconductors are characterized by atomic force microscopy and X-ray diffraction. The optical properties of the 2DOIP semiconductors are characterized from absorption and photoluminescence spectra measured at room and low temperatures. Influences of different components, in particular the organic parts, on the structural and optical properties of the 2DOIP semiconductors are discussed.

  8. Probing the effect of charge transfer enhancement in off resonance mode SERS via conjugation of the probe dye between silver nanoparticles and metal substrates.

    PubMed

    Selvakannan, Pr; Ramanathan, Rajesh; Plowman, Blake J; Sabri, Ylias M; Daima, Hemant K; O'Mullane, Anthony P; Bansal, Vipul; Bhargava, Suresh K

    2013-08-21

    The charge transfer-mediated surface enhanced Raman scattering (SERS) of crystal violet (CV) molecules that were chemically conjugated between partially polarized silver nanoparticles and optically smooth gold and silver substrates has been studied under off-resonant conditions. Tyrosine molecules were used as a reducing agent to convert silver ions into silver nanoparticles where oxidised tyrosine caps the silver nanoparticle surface with its semiquinone group. This binding through the quinone group facilitates charge transfer and results in partially oxidised silver. This establishes a chemical link between the silver nanoparticles and the CV molecules, where the positively charged central carbon of CV molecules can bind to the terminal carboxylate anion of the oxidised tyrosine molecules. After drop casting Ag nanoparticles bound with CV molecules it was found that the free terminal amine groups tend to bind with the underlying substrates. Significantly, only those CV molecules that were chemically conjugated between the partially polarised silver nanoparticles and the underlying gold or silver substrates were found to show SERS under off-resonant conditions. The importance of partial charge transfer at the nanoparticle/capping agent interface and the resultant conjugation of CV molecules to off resonant SERS effects was confirmed by using gold nanoparticles prepared in a similar manner. In this case the capping agent binds to the nanoparticle through the amine group which does not facilitate charge transfer from the gold nanoparticle and under these conditions SERS enhancement in the sandwich configuration was not observed.

  9. Supramolecular Low-Molecular-Weight Hydrogelator Stabilization of SERS-Active Aggregated Nanoparticles for Solution and Gas Sensing.

    PubMed

    Canrinus, Tjalling R; Lee, Wendy W Y; Feringa, Ben L; Bell, Steven E J; Browne, Wesley R

    2017-09-05

    The potential of surface-enhanced Raman scattering (SERS) spectroscopy in both laboratory and field analyses depends on the reliable formation of so-called SERS hot spots, such as those formed during gold or silver nanoparticle aggregation. Unfortunately such aggregates are not stable in solution because they typically grow until they precipitate. Here we describe the use of low-molecular-weight hydrogels formed through pH-triggered self-assembly that occurs at a rate that well matches the rates of aggregation of Au or Ag colloids, allowing them to be trapped at the SERS-active point in the aggregation process. We show that the colloid-containing gels give SERS signals similar to the parent colloid but are stable over several months. Moreover, lyophilized gels can be stored as dry powders for subsequent use in the analyses of gases and dissolved analytes by contact with either solutions or vapors. The present system shows how the combination of pH-switchable low-molecular-weight gelators and pH-induced colloid aggregation can be combined to make a highly stable, low-cost SERS platform for the detection of volatile organic compounds and the microvolume analysis of solutions.

  10. Incorporation of multilayered silver nanoparticles into polymer brushes as 3-dimensional SERS substrates and their application for bacteria detection

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Wang, Xiang-Dong; Tian, Ting; Chu, Li-Qiang

    2017-06-01

    Surface-enhanced Raman scattering (SERS) sensors have been extensively studied for ultrasensitive detection of diverse chemical or biological analytes. Facile fabrication of highly sensitive SERS substrates is believed to be of crucial importance in these analytical applications. In this regard, the preparation of 3-dimensional (3D) SERS substrates are explored via the incorporation of multilayered silver nanoparticles (AgNPs) into poly (oligo(ethylene glycol) methacrylate) (POEGMA) brushes by repeating the immersion-rinsing-drying steps for different lengths of time (i.e., the so-called in-stacking method). The POEGMA brushes of different chain lengths are synthesized by surface-initiated atom transfer radical polymerization (ATRP) with various reaction time. The resulting POEGMA/AgNP nanocomposites are characterized by FE-SEM, UV-vis and Raman spectroscopy. FE-SEM and UV-vis results indicate that the AgNPs are successfully incorporated into the POEGMA brushes with a 3D configuration. The nanocomposite films are employed as SERS substrates for the detection of a Raman reporter molecule (i.e., 4-aminothiophenol), giving rise to an enhancement factor of up to 1.29 × 107 and also having relatively good uniformity and reproducibility. The obtained 3D SERS substrates are also used for the detection of a typical gram-positive bacterium, Staphylococcus aureus. The limit of detection is found to be as low as ca. 8 CFU/mL.

  11. Ag-nanoparticle-decorated porous ZnO-nanosheets grafted on a carbon fiber cloth as effective SERS substrates

    NASA Astrophysics Data System (ADS)

    Wang, Zhiwei; Meng, Guowen; Huang, Zhulin; Li, Zhongbo; Zhou, Qitao

    2014-11-01

    We report on the large-scale synthesis of Ag-nanoparticle (Ag-NP) decorated ZnO-mesoporous-nanosheets (NSs) grafted on a flexible carbon fiber cloth (CFC), as sensitive and reproducible surface enhanced Raman scattering (SERS) substrates with excellent flexibility. The composite SERS-substrates are achieved by a combination of atomic layer deposition of ZnO-seeds on each fiber of the CFC (denoted as ZnO-seeds@CFC), chemical bath deposition and subsequent pyrolysis for the creation of ZnO-mesoporous-NSs grafted on ZnO-seeds@CFC, and ion-sputtering of Ag-NPs on the ZnO-mesoporous-NSs. As abundant SERS ``hot spots'' are generated from the electromagnetic coupling of the densely distributed Ag-NPs, and the semiconducting ZnO-mesoporous-NSs also have chemical supporting enhancement and distinct molecule adsorbing abilities, the composite SERS-substrates demonstrate high SERS-sensitivity with good signal reproducibility. As a trial for potential applications, the composite SERS-substrates were used to identify pesticides and highly toxic polychlorinated biphenyls (PCBs), and low concentrations down to 10-7 M for methyl parathion and 5 × 10-6 M for PCB-77 were reached, respectively, showing promising potential for the SERS-based rapid detection of toxic organic pollutants in the environment.We report on the large-scale synthesis of Ag-nanoparticle (Ag-NP) decorated ZnO-mesoporous-nanosheets (NSs) grafted on a flexible carbon fiber cloth (CFC), as sensitive and reproducible surface enhanced Raman scattering (SERS) substrates with excellent flexibility. The composite SERS-substrates are achieved by a combination of atomic layer deposition of ZnO-seeds on each fiber of the CFC (denoted as ZnO-seeds@CFC), chemical bath deposition and subsequent pyrolysis for the creation of ZnO-mesoporous-NSs grafted on ZnO-seeds@CFC, and ion-sputtering of Ag-NPs on the ZnO-mesoporous-NSs. As abundant SERS ``hot spots'' are generated from the electromagnetic coupling of the densely

  12. Nanoparticle cluster arrays for high-performance SERS through directed self-assembly on flat substrates and on optical fibers.

    PubMed

    Yap, Fung Ling; Thoniyot, Praveen; Krishnan, Sathiyamoorthy; Krishnamoorthy, Sivashankar

    2012-03-27

    We demonstrate template-guided self-assembly of gold nanoparticles into ordered arrays of uniform clusters suitable for high-performance SERS on both flat (silicon or glass) chips and an optical fiber faucet. Cluster formation is driven by electrostatic self-assembly of anionic citrate-stabilized gold nanoparticles (~11.6 nm diameter) onto two-dimensionally ordered polyelectrolyte templates realized by self-assembly of polystyrene-block-poly(2-vinylpyridine). A systematic variation is demonstrated for the number of particles (N ≈ 5, 8, 13, or 18) per cluster as well as intercluster separations (S(c) ≈ 37-10 nm). Minimum interparticle separations of <5 nm, intercluster separations of ~10 nm, and nanoparticle densities on surfaces as high as ~7 × 10(11)/in.(2) are demonstrated. Geometric modeling is used to support experimental data toward estimation of interparticle and intercluster separations in cluster arrays. Optical modeling and simulations using the finite difference time domain method are used to establish the influence of cluster size, shape, and intercluster separations on the optical properties of the cluster arrays in relation to their SERS performance. Excellent SERS performance, as evidenced by a high enhancement factor, >10(8) on flat chips and >10(7) for remote sensing, using SERS-enabled optical fibers is demonstrated. The best performing cluster arrays in both cases are achievable without the use of any expensive equipment or clean room processing. The demonstrated approach paves the way to significantly low-cost and high-throughput production of sensor chips or 3D-configured surfaces for remote sensing applications.

  13. A label-free gold-nanoparticle-based SERS assay for direct cyanide detection at the parts-per-trillion level.

    PubMed

    Senapati, Dulal; Dasary, Samuel S R; Singh, Anant K; Senapati, Tapas; Yu, Hongtao; Ray, Paresh C

    2011-07-18

    Cyanide is an extremely toxic lethal poison known to humankind. Developing rapid, highly sensitive, and selective detection of cyanide from water samples is extremely essential for human life safety. Driven by the need, here we report a gold-nanoparticle-based label-free surface-enhanced Raman spectroscopy (SERS) system for highly toxic cyanide ion recognition in parts-per-trillion level and to examine gold-nanoparticle-cyanide interaction. We have shown that the SERS assay can be used to probe the gold nanoparticle dissociation process in the presence of cyanide ions. Our experimental data indicates that gold-nanoparticle-based SERS can detect cyanide from a water sample at the 110 ppt level with excellent discrimination against other common anions and cations. The results also show that the SERS probe can be used to detect cyanide from environmental samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Organic/Inorganic Polymeric Composites for Heat-Transfer Reduction

    NASA Technical Reports Server (NTRS)

    Smith, Trent; Williams, Martha

    2008-01-01

    Organic/inorganic polymeric composite materials have been invented with significant reduction in heat-transfer properties. Measured decreases of 20-50 percent in thermal conductivity versus that of the unmodified polymer matrix have been attained. These novel composite materials also maintain mechanical properties of the unmodified polymer matrix. The present embodiments are applicable, but not limited to: racing applications, aerospace applications, textile industry, electronic applications, military hardware improvements, and even food service industries. One specific application of the polymeric composition is for use in tanks, pipes, valves, structural supports, and components for hot or cold fluid process systems where heat flow through materials is problematic and not desired. With respect to thermal conductivity and physical properties, these materials are superior alternatives to prior composite materials. These materials may prove useful as substitutes for metals in some cryogenic applications. A material of this type can be made from a blend of thermoplastics, elastomers, and appropriate additives and processed on normal polymer processing equipment. The resulting processed organic/inorganic composite can be made into fibers, molded, or otherwise processed into useable articles.

  15. Hybrid organic-inorganic rotaxanes and molecular shuttles.

    PubMed

    Lee, Chin-Fa; Leigh, David A; Pritchard, Robin G; Schultz, David; Teat, Simon J; Timco, Grigore A; Winpenny, Richard E P

    2009-03-19

    The tetravalency of carbon and its ability to form covalent bonds with itself and other elements enables large organic molecules with complex structures, functions and dynamics to be constructed. The varied electronic configurations and bonding patterns of inorganic elements, on the other hand, can impart diverse electronic, magnetic, catalytic and other useful properties to molecular-level structures. Some hybrid organic-inorganic materials that combine features of both chemistries have been developed, most notably metal-organic frameworks, dense and extended organic-inorganic frameworks and coordination polymers. Metal ions have also been incorporated into molecules that contain interlocked subunits, such as rotaxanes and catenanes, and structures in which many inorganic clusters encircle polymer chains have been described. Here we report the synthesis of a series of discrete rotaxane molecules in which inorganic and organic structural units are linked together mechanically at the molecular level. Structural units (dialkyammonium groups) in dumb-bell-shaped organic molecules template the assembly of essentially inorganic 'rings' about 'axles' to form rotaxanes consisting of various numbers of rings and axles. One of the rotaxanes behaves as a 'molecular shuttle': the ring moves between two binding sites on the axle in a large-amplitude motion typical of some synthetic molecular machine systems. The architecture of the rotaxanes ensures that the electronic, magnetic and paramagnetic characteristics of the inorganic rings-properties that could make them suitable as qubits for quantum computers-can influence, and potentially be influenced by, the organic portion of the molecule.

  16. A humidity sensing organic-inorganic composite for environmental monitoring.

    PubMed

    Ahmad, Zubair; Zafar, Qayyum; Sulaiman, Khaulah; Akram, Rizwan; Karimov, Khasan S

    2013-03-14

    In this paper, we present the effect of varying humidity levels on the electrical parameters and the multi frequency response of the electrical parameters of an organic-inorganic composite (PEPC+NiPc+Cu2O)-based humidity sensor. Silver thin films (thickness ~200 nm) were primarily deposited on plasma cleaned glass substrates by the physical vapor deposition (PVD) technique. A pair of rectangular silver electrodes was formed by patterning silver film through standard optical lithography technique. An active layer of organic-inorganic composite for humidity sensing was later spun coated to cover the separation between the silver electrodes. The electrical characterization of the sensor was performed as a function of relative humidity levels and frequency of the AC input signal. The sensor showed reversible changes in its capacitance with variations in humidity level. The maximum sensitivity ~31.6 pF/%RH at 100 Hz in capacitive mode of operation has been attained. The aim of this study was to increase the sensitivity of the previously reported humidity sensors using PEPC and NiPc, which has been successfully achieved.

  17. A Humidity Sensing Organic-Inorganic Composite for Environmental Monitoring

    PubMed Central

    Ahmad, Zubair; Zafar, Qayyum; Sulaiman, Khaulah; Akram, Rizwan; Karimov, Khasan S.

    2013-01-01

    In this paper, we present the effect of varying humidity levels on the electrical parameters and the multi frequency response of the electrical parameters of an organic-inorganic composite (PEPC+NiPc+Cu2O)-based humidity sensor. Silver thin films (thickness ∼200 nm) were primarily deposited on plasma cleaned glass substrates by the physical vapor deposition (PVD) technique. A pair of rectangular silver electrodes was formed by patterning silver film through standard optical lithography technique. An active layer of organic-inorganic composite for humidity sensing was later spun coated to cover the separation between the silver electrodes. The electrical characterization of the sensor was performed as a function of relative humidity levels and frequency of the AC input signal. The sensor showed reversible changes in its capacitance with variations in humidity level. The maximum sensitivity ∼31.6 pF/%RH at 100 Hz in capacitive mode of operation has been attained. The aim of this study was to increase the sensitivity of the previously reported humidity sensors using PEPC and NiPc, which has been successfully achieved. PMID:23493124

  18. Theory of hydrogen migration in organic-inorganic halide perovskites.

    PubMed

    Egger, David A; Kronik, Leeor; Rappe, Andrew M

    2015-10-12

    Solar cells based on organic-inorganic halide perovskites have recently been proven to be remarkably efficient. However, they exhibit hysteresis in their current-voltage curves, and their stability in the presence of water is problematic. Both issues are possibly related to a diffusion of defects in the perovskite material. By using first-principles calculations based on density functional theory, we study the properties of an important defect in hybrid perovskites-interstitial hydrogen. We show that differently charged defects occupy different crystal sites, which may allow for ionization-enhanced defect migration following the Bourgoin-Corbett mechanism. Our analysis highlights the structural flexibility of organic-inorganic perovskites: successive iodide displacements, combined with hydrogen bonding, enable proton diffusion with low migration barriers. These findings indicate that hydrogen defects can be mobile and thus highly relevant for the performance of perovskite solar cells. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  19. Biomimetic synthesis of highly biocompatible gold nanoparticles with amino acid-dithiocarbamate as a precursor for SERS imaging

    NASA Astrophysics Data System (ADS)

    Li, Li; Liu, Jianbo; Yang, Xiaohai; Huang, Jin; He, Dinggeng; Guo, Xi; Wan, Lan; He, Xiaoxiao; Wang, Kemin

    2016-03-01

    Amino acid-dithiocarbamate (amino acid-DTC) was developed as both the reductant and ligand stabilizer for biomimetic synthesis of gold nanoparticles (AuNPs), which served as an excellent surface-enhanced Raman scattering (SERS) contrast nanoprobe for cell imaging. Glycine (Gly), glutamic acid (Glu), and histidine (His) with different isoelectric points were chosen as representative amino acid candidates to synthesize corresponding amino acid-DTC compounds through mixing with carbon disulfide (CS2), respectively. The pyrogenic decomposition of amino acid-DTC initiated the reduction synthesis of AuNPs, and the strong coordinating dithiocarbamate group of amino acid-DTC served as a stabilizer that grafted onto the surface of the AuNPs, which rendered the as-prepared nanoparticles a negative surface charge and high colloidal stability. MTT cell viability assay demonstrated that the biomimetic AuNPs possessed neglectful toxicity to the human hepatoma cell, which guaranteed them good biocompatibility for biomedical application. Meanwhile, the biomimetic AuNPs showed a strong SERS effect with an enhancement factor of 9.8 × 105 for the sensing of Rhodamine 6G, and two distinct Raman peaks located at 1363 and 1509 cm-1 could be clearly observed in the cell-imaging experiments. Therefore, biomimetic AuNPs can be explored as an excellent SERS contrast nanoprobe for biomedical imaging, and the amino acid-DTC mediated synthesis of the AuNPs has a great potential in bio-engineering and biomedical imaging applications.

  20. A versatile SERS-based immunoassay for immunoglobulin detection using antigen-coated gold nanoparticles and malachite green-conjugated protein A/G

    USDA-ARS?s Scientific Manuscript database

    A surface enhanced Raman scattering (SERS) immunoassay for antibody detection in serum is described in the present work. The developed assay is conducted in solution and utilizes Au nanoparticles coated with the envelope (E) protein of West Nile Virus (WNV) as the SERS-active substrate and malachite...

  1. Mesoporous titania based yolk-shell nanoparticles as multifunctional theranostic platforms for SERS imaging and chemo-photothermal treatment.

    PubMed

    Zhang, Weiwei; Wang, Yunqing; Sun, Xiuyan; Wang, Wenhai; Chen, Lingxin

    2014-11-06

    Recently surface-enhanced Raman scattering (SERS) imaging guided theranostic nanoplatforms have attracted considerable attention. Herein, we developed novel yolk-shell gold nanorod@void@mesoporous titania nanoparticles (AuNR@void@mTiO₂ NPs) for simultaneous SERS imaging and chemo-photothermal therapy. Our work showed three highlighted features: first, we proposed a facile and versatile "up to down" SERS labeling strategy for the drug delivery system, in which "empty carriers" were pre-synthesized, followed by co-loading of Raman reporters on AuNR and anti-cancer drug doxorubicin (DOX) in mTiO₂ in sequence. The acquired SERS signal was strong enough for tracking NPs at both living cells and mice levels. Second, we selected mTiO₂ as a novel drug loading material instead of the widely used mesoporous silica (mSiO₂). The mTiO₂ shared satisfactory drug loading and release behavior as mSiO₂ but it was chemically inert. This property not only provided a facile way to form a yolk-shell structure but also rendered it with superior structural stability in a biological system. Third, the near infrared (NIR) light absorbing property of the AuNR SERS substrate was also explored for drug release regulation and photothermal treatment. Significantly greater MCF-7 cell killing was observed when treated together with DOX-loaded NPs and NIR laser irradiation, attributable to the synergistic chemo-thermal therapeutic effect. Our results indicated the established SERS labeled yolk-shell NP as a promising theranostic platform and suggested its potential in vivo applications.

  2. Efficient intracellular delivery and improved biocompatibility of colloidal silver nanoparticles towards intracellular SERS immuno-sensing.

    PubMed

    Bhardwaj, Vinay; Srinivasan, Supriya; McGoron, Anthony J

    2015-06-21

    High throughput intracellular delivery strategies, electroporation, passive and TATHA2 facilitated diffusion of colloidal silver nanoparticles (AgNPs) are investigated for cellular toxicity and uptake using state-of-art analytical techniques. The TATHA2 facilitated approach efficiently delivered high payload with no toxicity, pre-requisites for intracellular applications of plasmonic metal nanoparticles (PMNPs) in sensing and therapeutics.

  3. Novel SERS materials for multiplex biomolecular detection via controlled nanoparticle linking and polymer encapsulation

    SciTech Connect

    Braun, G B; Lee, S J; Laurence, T; Fera, N; Fabris, L; Bazan, G C; Moskovits, M; Reich, N O

    2008-07-21

    Over the past decade the emphasis on single-molecule sensitivity of surface-enhanced Raman spectroscopy (SERS) has brought to prominence the special role played by so-called SERS 'hot spots', oftentimes nanometer-scale junctions between nanostructures. In this report, optimally SERS enhancing silver clusters were synthesized using bifunctional linkers and polymer and/or protein encapsulation. The synthesis, which results in stable clusters even when stored for months or dried and re-dissolved, is scalable to large quantities. Using a sacrificial linker approach we also employ a permeable polymer/protein shell for general small molecule sensing. Finally, we utilize these nanomaterials by tagging specific epitopes on cancer cells and show that SERS signals from single clusters can be measured routinely.

  4. Solution-based direct readout surface enhanced Raman spectroscopic (SERS) detection of ultra-low levels of thiram with dogbone shaped gold nanoparticles.

    PubMed

    Saute, Benjamin; Narayanan, Radha

    2011-02-07

    We report the use of two different sizes of dogbone shaped gold nanoparticles as colloidal substrates for surface enhanced Raman spectroscopy (SERS) based detection of ultra-low levels of thiram, a dithiocarbamate fungicide. We demonstrate the ability to use a solution based, direct readout SERS method as a quantitative tool for the detection of ultra-low levels of thiram. The two different sizes of dogbone shaped gold nanoparticles are synthesized by using the seed-mediated growth method and characterized by using UV-visible spectroscopy and transmission electron microscopy (TEM). The smaller dogbone shaped nanoparticles have an average size of 43 ± 13 nm. The larger dogbone shaped gold nanoparticles have an average size of 65 ± 15 nm. The nanoparticle concentration is 1.25 × 10(11) nanoparticles per mL for the smaller dogbone shaped gold nanoparticles and is 1.13 × 10(11) nanoparticles per mL for the larger dogbone shaped gold nanoparticles. Different concentrations of thiram are allowed to bind to the two different sizes of dogbone shaped gold nanoparticles and the SERS spectra are obtained. From the calibration curve, the limit of detection for thiram is 43.9 ± 6.2 nM when the smaller dogbone shaped gold nanoparticles are used as colloidal SERS substrates In the case of the larger dogbone shaped gold nanoparticles, the limit of detection for thiram is 11.8 ± 3.2 nM. The lower limit of detection obtained by using the larger dogbone shaped gold nanoparticles as colloidal substrates is due to the lightning rod effect, higher contributions from the electromagnetic enhancement effect, and larger number of surface sites for thiram to bind.

  5. A highly sensitive and recyclable SERS substrate based on Ag-nanoparticle-decorated ZnO nanoflowers in ordered arrays.

    PubMed

    Tao, Qiang; Li, Shuai; Ma, Chunyu; Liu, Kun; Zhang, Qing-Yu

    2015-02-21

    Using a patterned sapphire substrate with a hemisphere array, flower-like ZnO nanorods grouped in a highly ordered array were fabricated on the wafer scale by routine solution growth. After decorating with high-density Ag nanoparticles (NPs), the ZnO nanoflower arrays were used as the substrates for surface enhanced Raman scattering (SERS). Using Rhodamine 6G as the probe molecules with a concentration down to 10(-10) M, the SERS substrates present an as high as 10(10) Raman enhancement with good reproducibility. The influence of Ag NP decoration on the SERS activity was explored and the sub-10 nm nanogaps between the adjacent Ag NPs were proved to be the primary electromagnetic "hot spots" responsible for the significant Raman enhancement. The Ag-NP-decorated ZnO nanoflower arrays were demonstrated to possess a self-cleaning function enabled by UV irradiation via photocatalytic degradation of the analyte molecules. In addition, the SERS substrate exhibited an extremely long service lifetime, possibly due to its superhydrophobicity and storage in the dark and a dry environment.

  6. Dual-Mode SERS-Fluorescence Immunoassay Using Graphene Quantum Dot Labeling on One-Dimensional Aligned Magnetoplasmonic Nanoparticles.

    PubMed

    Zou, Fengming; Zhou, Hongjian; Tan, Tran Van; Kim, Jeonghyo; Koh, Kwangnak; Lee, Jaebeom

    2015-06-10

    A novel dual-mode immunoassay based on surface-enhanced Raman scattering (SERS) and fluorescence was designed using graphene quantum dot (GQD) labels to detect a tuberculosis (TB) antigen, CFP-10, via a newly developed sensing platform of linearly aligned magnetoplasmonic (MagPlas) nanoparticles (NPs). The GQDs were excellent bilabeling materials for simultaneous Raman scattering and photoluminescence (PL). The one-dimensional (1D) alignment of MagPlas NPs simplified the immunoassay process and enabled fast, enhanced signal transduction. With a sandwich-type immunoassay using dual-mode nanoprobes, both SERS signals and fluorescence images were recognized in a highly sensitive and selective manner with a detection limit of 0.0511 pg mL(-1).

  7. An unconventional route to monodisperse and intimately contacted semiconducting organic-inorganic nanocomposites.

    PubMed

    Xu, Hui; Pang, Xinchang; He, Yanjie; He, Ming; Jung, Jaehan; Xia, Haiping; Lin, Zhiqun

    2015-04-07

    We developed an unconventional route to produce uniform and intimately contacted semiconducting organic-inorganic nanocomposites for potential applications in thermoelectrics. By utilizing amphiphilic star-like PAA-b-PEDOT diblock copolymer as template, monodisperse PEDOT-functionalized lead telluride (PbTe) nanoparticles were crafted via the strong coordination interaction between PAA blocks of star-like PAA-b-PEDOT and the metal moieties of precursors (i.e., forming PEDOT-PbTe nanocomposites). As the inner PAA blocks are covalently connected to the outer PEDOT blocks, the PEDOT chains are intimately and permanently tethered on the PbTe nanoparticle surface, thereby affording a well-defined PEDOT/PbTe interface, which prevents the PbTe nanoparticles from aggregation, and more importantly promotes the long-term stability of PEDOT-PbTe nanocomposites. We envision that the template strategy is general and robust, and offers easy access to other conjugated polymer-inorganic semiconductor nanocomposites for use in a variety of applications.

  8. One-step green synthesis of high uniform SERS substrate based on Au nanoparticles grown on Ge wafer

    NASA Astrophysics Data System (ADS)

    Zhou, Juhong; Zhu, Feng; Wang, Yan; Wang, Tao

    2015-05-01

    Highly sensitive, large-area and uniform surface-enhanced Raman scattering (SERS) substrates based on gold nanoparticles grown on Ge wafer have been fabricated by a one-step green reaction. The results showed that these substrates exhibited admirable performance in the low concentration detection (1 × 10-7 M) of Rhodamine 6G with the enhancement factor of 4.5 × 106 and remarkable uniformity with relative standard deviation less than 8%. The uniform enhancement was also obtained in the aqueous detection of malachite green. During the experiments, the Raman spectra were recorded in the solution to pursue the uniformity, reproducibility and stability of signals.

  9. An organic-inorganic perovskite ferroelectric with large piezoelectric response

    NASA Astrophysics Data System (ADS)

    You, Yu-Meng; Liao, Wei-Qiang; Zhao, Dewei; Ye, Heng-Yun; Zhang, Yi; Zhou, Qionghua; Niu, Xianghong; Wang, Jinlan; Li, Peng-Fei; Fu, Da-Wei; Wang, Zheming; Gao, Song; Yang, Kunlun; Liu, Jun-Ming; Li, Jiangyu; Yan, Yanfa; Xiong, Ren-Gen

    2017-07-01

    Molecular piezoelectrics are highly desirable for their easy and environment-friendly processing, light weight, low processing temperature, and mechanical flexibility. However, although 136 years have passed since the discovery in 1880 of the piezoelectric effect, molecular piezoelectrics with a piezoelectric coefficient d33 comparable with piezoceramics such as barium titanate (BTO; ~190 picocoulombs per newton) have not been found. We show that trimethylchloromethyl ammonium trichloromanganese(II), an organic-inorganic perovskite ferroelectric crystal processed from aqueous solution, has a large d33 of 185 picocoulombs per newton and a high phase-transition temperature of 406 kelvin (K) (16 K above that of BTO). This makes it a competitive candidate for medical, micromechanical, and biomechanical applications.

  10. Recent NMR developments applied to organic-inorganic materials.

    PubMed

    Bonhomme, Christian; Gervais, Christel; Laurencin, Danielle

    2014-02-01

    In this contribution, the latest developments in solid state NMR are presented in the field of organic-inorganic (O/I) materials (or hybrid materials). Such materials involve mineral and organic (including polymeric and biological) components, and can exhibit complex O/I interfaces. Hybrids are currently a major topic of research in nanoscience, and solid state NMR is obviously a pertinent spectroscopic tool of investigation. Its versatility allows the detailed description of the structure and texture of such complex materials. The article is divided in two main parts: in the first one, recent NMR methodological/instrumental developments are presented in connection with hybrid materials. In the second part, an exhaustive overview of the major classes of O/I materials and their NMR characterization is presented. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Organic/Inorganic Hybrid Polymer/Clay Nanocomposites

    NASA Technical Reports Server (NTRS)

    Park, Cheol; Connell, John W.; Smith, Joseph G., Jr.

    2003-01-01

    A novel class of polymer/clay nanocomposites has been invented in an attempt to develop transparent, lightweight, durable materials for a variety of aerospace applications. As their name suggests, polymer/ clay nanocomposites comprise organic/ inorganic hybrid polymer matrices containing platelet-shaped clay particles that have sizes of the order of a few nanometers thick and several hundred nanometers long. Partly because of their high aspect ratios and high surface areas, the clay particles, if properly dispersed in the polymer matrix at a loading level of 1 to 5 weight percent, impart unique combinations of physical and chemical properties that make these nanocomposites attractive for making films and coatings for a variety of industrial applications. Relative to the unmodified polymer, the polymer/ clay nanocomposites may exhibit improvements in strength, modulus, and toughness; tear, radiation, and fire resistance; and lower thermal expansion and permeability to gases while retaining a high degree of optical transparency.

  12. Chemically diverse and multifunctional hybrid organic-inorganic perovskites

    NASA Astrophysics Data System (ADS)

    Li, Wei; Wang, Zheming; Deschler, Felix; Gao, Song; Friend, Richard H.; Cheetham, Anthony K.

    2017-02-01

    Hybrid organic-inorganic perovskites (HOIPs) can have a diverse range of compositions including halides, azides, formates, dicyanamides, cyanides and dicyanometallates. These materials have several common features, including their classical ABX3 perovskite architecture and the presence of organic amine cations that occupy the A-sites. Current research in HOIPs tends to focus on metal halide HOIPs, which show promise for use in solar cells and optoelectronic devices; however, the other subclasses also exhibit a diverse range of physical properties. In this Review, we summarize the chemical variability and structural diversity of all known HOIP subclasses. We also present a comprehensive account of their intriguing physical properties, including photovoltaic and optoelectronic properties, dielectricity, magnetism, ferroelectricity, ferroelasticity and multiferroicity. Moreover, we discuss the current challenges and future opportunities in this exciting field.

  13. Giant photostriction in organic-inorganic lead halide perovskites

    NASA Astrophysics Data System (ADS)

    Zhou, Yang; You, Lu; Wang, Shiwei; Ku, Zhiliang; Fan, Hongjin; Schmidt, Daniel; Rusydi, Andrivo; Chang, Lei; Wang, Le; Ren, Peng; Chen, Liufang; Yuan, Guoliang; Chen, Lang; Wang, Junling

    2016-04-01

    Among the many materials investigated for next-generation photovoltaic cells, organic-inorganic lead halide perovskites have demonstrated great potential thanks to their high power conversion efficiency and solution processability. Within a short period of about 5 years, the efficiency of solar cells based on these materials has increased dramatically from 3.8 to over 20%. Despite the tremendous progress in device performance, much less is known about the underlying photophysics involving charge-orbital-lattice interactions and the role of the organic molecules in this hybrid material remains poorly understood. Here, we report a giant photostrictive response, that is, light-induced lattice change, of >1,200 p.p.m. in methylammonium lead iodide, which could be the key to understand its superior optical properties. The strong photon-lattice coupling also opens up the possibility of employing these materials in wireless opto-mechanical devices.

  14. Shape-Controlled Synthesis of Palladium Nanoparticles and Their SPR/SERS Properties

    NASA Astrophysics Data System (ADS)

    Shen, Xiao-shuang; Wang, Guan-zhong; Hong, Xun; Zhu, Wei

    2009-08-01

    Morphological evolution of Pd nanoparticles was studied in a solution-phase synthesis using cetyltrimethylammonium bromide (CTAB) and CTAB/sodium citrate mixture as capping agents, respectively. The morphological diversity of Pd nanoparticles is the combined effect of different Pd twinned seeds formed in the nucleation stage and selectively enlarging one set of crystallographic facets in the growth stage, both of which can be affected by the concentrations of CTAB. Through changing the concentrations of CTAB and sodium ascorbate, Pd nanoparticles with different shapes were obtained. When citrate ions were introduced to manipulate the nucleation and growth process, star-shaped icosahedra and nanorods with pentagram cross-sections were obtained. Pd nanoparticles with different shapes have quite different surface plasmon resonance and surface-enhanced Raman scattering properties.

  15. Plasmonic core-shell nanoparticles for SERS detection of the pesticide thiram: size- and shape-dependent Raman enhancement

    NASA Astrophysics Data System (ADS)

    Guo, Pengzhen; Sikdar, Debabrata; Huang, Xiqiang; Si, Kae Jye; Xiong, Wei; Gong, Shu; Yap, Lim Wei; Premaratne, Malin; Cheng, Wenlong

    2015-02-01

    We systematically investigated the size- and shape-dependent SERS activities of plasmonic core-shell nanoparticles towards detection of the pesticide thiram. Monodisperse Au@Ag nanocubes (NCs) and Au@Ag nanocuboids (NBs) were synthesized and their Ag shell thickness was precisely adjusted from ~1 nm to ~16 nm. All these nanoparticles were used as SERS substrates for thiram detection, and the Raman intensities with three different lasers (514 nm, 633 nm and 782 nm) were recorded and compared. Our results clearly show that: (1) the excitation wavelength discriminated particle shapes regardless of particle sizes, and the maximized Raman enhancement was observed when the excitation wavelength approaches the SERS peak (provided there is significant local electric field confinement on the plasmonic nanostructures at that wavelength); (2) at the optimized laser wavelength, the maximum Raman enhancement was achieved at a certain threshold of particle size (or silver coating thickness). By exciting particles at their optimized sizes with the corresponding optimized laser wavelengths, we achieved a detection limit of roughly around 100 pM and 80 pM for NCs and NBs, respectively.We systematically investigated the size- and shape-dependent SERS activities of plasmonic core-shell nanoparticles towards detection of the pesticide thiram. Monodisperse Au@Ag nanocubes (NCs) and Au@Ag nanocuboids (NBs) were synthesized and their Ag shell thickness was precisely adjusted from ~1 nm to ~16 nm. All these nanoparticles were used as SERS substrates for thiram detection, and the Raman intensities with three different lasers (514 nm, 633 nm and 782 nm) were recorded and compared. Our results clearly show that: (1) the excitation wavelength discriminated particle shapes regardless of particle sizes, and the maximized Raman enhancement was observed when the excitation wavelength approaches the SERS peak (provided there is significant local electric field confinement on the plasmonic

  16. Graphene oxide-Ag nanoparticles-pyramidal silicon hybrid system for homogeneous, long-term stable and sensitive SERS activity

    NASA Astrophysics Data System (ADS)

    Guo, Jia; Xu, Shicai; Liu, Xiaoyun; Li, Zhe; Hu, Litao; Li, Zhen; Chen, Peixi; Ma, Yong; Jiang, Shouzhen; Ning, Tingyin

    2017-02-01

    In our work, few layers graphene oxide (GO) were directly synthesized on Ag nanoparticles (AgNPs) by spin-coating method to fabricate a GO-AgNPs hybrid structure on a pyramidal silicon (PSi) substrate for surface-enhanced Raman scattering (SERS). The GO-AgNPs-PSi substrate showed excellent Raman enhancement effect, the minimum detected concentration for Rhodamine 6G (R6G) can reach 10-12 M, which is one order of magnitude lower than the AgNPs-PSi substrate and two order of magnitude lower than the GO-AgNPs-flat-Si substrate. The linear fit calibration curve with error bars is presented and the value of R2 of 612 and 773 cm-1 can reach 0.986 and 0.980, respectively. The excellent linear response between the Raman intensity and R6G concentrations prove that the prepared GO-AgNPs-PSi substrates can serve as good SERS substrate for molecule detection. The maximum deviations of SERS intensities from 20 positions of the GO-AgNPs-PSi substrate are less than 8%, revealing the high homogeneity of the SERS substrate. The excellent homogeneity of the enhanced Raman signals can be attributed to well-separated pyramid arrays of PSi, the uniform morphology of AgNPs and multi-functions of GO layer. Besides, the uniform GO film can effectively protect AgNPs from oxidation and endow the hybrid system a good stability and long lifetime. This GO-AgNPs-PSi substrate may provide a new way toward practical applications for the ultrasensitive and label-free SERS detection in areas of medicine, food safety and biotechnology.

  17. Ag nanoparticles as multifunctional SERS substrate for the adsorption, degradation and detection of dye molecules

    NASA Astrophysics Data System (ADS)

    Ma, Yongmei; Ding, Qianqian; Yang, Liangbao; Zhang, Li; Shen, Yuhua

    2013-01-01

    Ag NPs were obtained by isopropyl alcohol restore silver nitrate with silicotungstic acid as a stabilizer under the condition of UV irradiation. From changing the amount of isopropyl alcohol and silver nitrate, we obtained Ag NPs of which plasmon peak was similar to the excitation wavelength, and the enhancement effect will be greatly improved. Enriching, degrading, and detecting dye molecular can be achieved by the simple SERS substrate, and the photo-degradation process was monitored by SERS successfully for the first time, and the sensitivity was improved compare to traditional detection by UV-vis spectroscopy.

  18. SERS detection of uranyl using functionalized gold nanostars promoted by nanoparticle shape and size.

    PubMed

    Lu, Grace; Forbes, Tori Z; Haes, Amanda J

    2016-08-15

    The radius of curvature of gold (Au) nanostar tips but not the overall particle dimensions can be used for understanding the large and quantitative surface-enhanced Raman scattering (SERS) signal of the uranyl (UO2)(2+) moiety. The engineered roughness of the Au nanostar architecture and the distance between the gold surface and uranyl cations are promoted using carboxylic acid terminated alkanethiols containing 2, 5, and 10 methylene groups. By systematically varying the self-assembled monolayer (SAM) thickness with these molecules, the localized surface plasmon resonance (LSPR) spectral properties are used to quantify the SAM layer thickness and to promote uranyl coordination to the Au nanostars in neutral aqueous solutions. Successful uranyl detection is demonstrated for all three functionalized Au nanostar samples as indicated by enhanced signals and red-shifts in the symmetric U(vi)-O stretch. Quantitative uranyl detection is achieved by evaluating the integrated area of these bands in the uranyl fingerprint window. By varying the concentration of uranyl, similar free energies of adsorption are observed for the three carboxylic acid terminated functionalized Au nanostar samples indicating similar coordination to uranyl, but the SERS signals scale inversely with the alkanethiol layer thickness. This distance dependence follows previously established models assuming that roughness features associated with the radius of curvature of the tips are considered. These results indicate that SERS signals using functionalized Au nanostar substrates can provide quantitative detection of small molecules and that the tip architecture plays an important role in understanding the resulting SERS intensities.

  19. Antibacterial activity of plastics coated with silver-doped organic-inorganic hybrid coatings prepared by sol-gel processes.

    PubMed

    Marini, M; De Niederhausern, S; Iseppi, R; Bondi, M; Sabia, C; Toselli, M; Pilati, F

    2007-04-01

    Silver-doped organic-inorganic hybrid coatings were prepared starting from tetraethoxysilane- and triethoxysilane-terminated poly(ethylene glycol)-block-polyethylene by the sol-gel process. They were applied as a thin layer (0.6-1.1 microm) to polyethylene (PE) and poly(vinyl chloride) (PVC) films and the antibacterial activity of the coated films was tested against Gram-negative (Escherichia coli ATCC 25922) and Gram-positive (Staphylococcus aureus ATCC 6538) bacteria. The effect of several factors (such as organic-inorganic ratio, type of catalyst, time of post-curing, silver ion concentration, etc.) was investigated. Measurements at different contact times showed a rapid decrease of the viable count for both tested strains. The highest antibacterial activity [more than 6 log reduction within 6 h starting from 106 colony-forming units (cfu) mL-1] was obtained for samples with an organic-inorganic weight ratio of 80:20 and 5 wt % silver salt with respect to the coating. For the coatings prepared by an acid-catalyzed process, a high level of permanence of the antibacterial activity of the coated films was demonstrated by repeatedly washing the samples in warm water or by immersion in physiological saline solution at 37 degrees C for 3 days. The release of silver ions per square meter of coating is very similar to that previously observed for polyamides filled with metallic silver nanoparticles; however, when compared on the basis of Ag content, the concentration of silver ions released from the coating is much higher than that released from 1 mm thick specimens of polyamide (PA) filled with silver nanoparticles. Transparency and good adhesion of the coating to PE and PVC plastic substrates without any previous surface treatment are further interesting features.

  20. Synthesis of silver nanoparticles in the presence of diethylaminoethyl-dextran hydrochloride polymer and their SERS activity

    NASA Astrophysics Data System (ADS)

    Mikac, L.; Jurkin, T.; Štefanić, G.; Ivanda, Mile; Gotić, Marijan

    2017-09-01

    The silver nanoparticles (AgNPs) were synthesized upon γ-irradiation of AgNO3 precursor suspensions in the presence of diethylaminoethyl-dextran hydrochloride (DEAE-dextran) cationic polymer as a stabilizer. The dose rate of γ-irradiation was 32 kGy h-1, and absorbed doses were 30 and 60 kGy. The γ-irradiation of the precursor suspension at acidic or neutral pH conditions produced predominantly the silver(I) chloride (AgCl) particles, because of the poor solubility of AgCl already present in the precursor suspension. The origin of AgCl in the precursor suspension was due to the presence of chloride ions in DEAE-dextran hydrochloride polymer. The addition of ammonia to the precursor suspension dissolved the AgCl precipitate, and the γ-irradiation of such colourless suspension at alkali pH produced a stable aqueous suspension with rather uniform spherical AgNPs of approximately 30 nm in size. The size of AgNPs was controlled by varying the AgNO3/DEAE-dextran concentration in the suspensions. The surface-enhanced Raman scattering (SERS) activities of synthesized AgNPs were examined using organic molecules rhodamine 6G, pyridine and 4-mercaptobenzoic acid (4-MBA). The NaBH4 was used as SERS aggregation agent. The SERS results have shown that in the presence of synthesized AgNPs, it was possible to detect low concentration of tested compounds.

  1. Silver nanoparticles on GaSb nanodots: a LSPR-boosted binary platform for broadband light harvesting and SERS

    NASA Astrophysics Data System (ADS)

    Bhatnagar, Mukul; Ranjan, Mukesh; Mukherjee, Subroto

    2015-02-01

    We report the LSPR-augmented optical response of silver nanoparticle-topped GaSb nanodots produced by low-energy ion beam irradiation. Nanostructure ordering and interdot gap play crucial roles for inducing the LSPR effect, enhancing the absorbing capacity of the structure as validated by reflection measurements. The measured size of silver-capped GaSb nanodot varies from 28 to 48 nm. Enhanced plasmon coupling for the 600 eV configuration initiates the presence of giant electromagnetic fields as confirmed by LSPR and SERS measurements. Anisotropic Bruggeman effective medium approximation was performed to match the experimentally observed optical response of the nanostructure. Calculated screening factor values of 0.29 and 0.23 for 600 and 800 eV ion energy produced nanodot configurations were obtained, respectively, which are in tune with the measured reflected and SERS signal. The calculated dielectric constants confirm the directional anisotropy along the length of the silver-capped GaSb nanodots. The proposed model successfully matches the void fraction and nanostructure height in accordance with SEM and reported TEM measurements. Thus, the model developed can be used to optimize the maximum plasmonic coupling efficiency among the dots. We propose two key applications for this nanostructure, first as an absorptive substrate for deep space photovoltaics and second to act as an effective SERS substrate.

  2. A three-dimensional silver nanoparticles decorated plasmonic paper strip for SERS detection of low-abundance molecules.

    PubMed

    Li, Yixin; Zhang, Kun; Zhao, Jingjing; Ji, Ji; Ji, Chang; Liu, Baohong

    2016-01-15

    The fabrication of SERS substrates, which can offer the advantages of strong Raman signal enhancement with good reproducibility and low cost, is still a challenge for practical applications. In this work, a simple three-dimensional (3D) paper-based SERS substrate, which contains plasmonic silver-nanoparticles (AgNPs), has been developed by the silver mirror reaction. This paper strip was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), etc. Pretreatment of the paper as well as the reaction time, temperature, and reagent concentrations for the silver mirror reaction were varied for further studies. With the optimized experimental parameters, the AgNPs synthesized and distributed in-situ on the paper strip could give more favorable SERS performance. The limit of detection (LOD) as low as 10(-11)M for Rhodamine 6G (R6G) and 10(-9)M for p-aminothiophenol (p-ATP) plus wide linear range for the log-log plot of Raman intensity versus analyte concentration were achieved. The detection of R6G in rain water was also carried out successfully. The merits of this protocol include low cost, easy operation, high sensitivity and acceptable stability, which make it ideal for the detection of environmental samples in trace amounts.

  3. Highly sensitive, reproducible and stable SERS substrate based on reduced graphene oxide/silver nanoparticles coated weighing paper

    NASA Astrophysics Data System (ADS)

    Xiao, Guina; Li, Yunxiang; Shi, Wangzhou; Shen, Leo; Chen, Qi; Huang, Lei

    2017-05-01

    Paper-based surface-enhanced Raman scattering (SERS) substrates receive a great deal of attention due to low cost and high flexibility. Herein, we developed an efficient SERS substrate by gravure printing of sulfonated reduced graphene-oxide (S-RGO) thin film and inkjet printing of silver nanoparticles (AgNPs) on weighing paper successively. Malachite green (MG) and rhodamine 6G (R6G) were chosen as probe molecules to evaluate the enhanced performance of the fabricated SERS-active substrates. It was found that the S-RGO/AgNPs composite structure possessed higher enhancement ability than the pure AgNPs. The Raman enhancement factor of S-RGO/AgNPs was calculated to be as large as 109. The minimum detection limit for MG and R6G was down to 10-7 M with good linear responses (R2 = 0.9996, 0.9983) range from 10-4 M to 10-7 M. In addition, the S-RGO/AgNPs exhibited good uniformity with a relative standard deviation (RSD) of 7.90% measured by 572 points, excellent reproducibility with RSD smaller than 3.36%, and long-term stability with RSD less than 7.19%.

  4. Biomimetic synthesis of highly biocompatible gold nanoparticles with amino acid-dithiocarbamate as a precursor for SERS imaging.

    PubMed

    Li, Li; Liu, Jianbo; Yang, Xiaohai; Huang, Jin; He, Dinggeng; Guo, Xi; Wan, Lan; He, Xiaoxiao; Wang, Kemin

    2016-03-11

    Amino acid-dithiocarbamate (amino acid-DTC) was developed as both the reductant and ligand stabilizer for biomimetic synthesis of gold nanoparticles (AuNPs), which served as an excellent surface-enhanced Raman scattering (SERS) contrast nanoprobe for cell imaging. Glycine (Gly), glutamic acid (Glu), and histidine (His) with different isoelectric points were chosen as representative amino acid candidates to synthesize corresponding amino acid-DTC compounds through mixing with carbon disulfide (CS2), respectively. The pyrogenic decomposition of amino acid-DTC initiated the reduction synthesis of AuNPs, and the strong coordinating dithiocarbamate group of amino acid-DTC served as a stabilizer that grafted onto the surface of the AuNPs, which rendered the as-prepared nanoparticles a negative surface charge and high colloidal stability. MTT cell viability assay demonstrated that the biomimetic AuNPs possessed neglectful toxicity to the human hepatoma cell, which guaranteed them good biocompatibility for biomedical application. Meanwhile, the biomimetic AuNPs showed a strong SERS effect with an enhancement factor of 9.8 × 10(5) for the sensing of Rhodamine 6G, and two distinct Raman peaks located at 1363 and 1509 cm(-1) could be clearly observed in the cell-imaging experiments. Therefore, biomimetic AuNPs can be explored as an excellent SERS contrast nanoprobe for biomedical imaging, and the amino acid-DTC mediated synthesis of the AuNPs has a great potential in bio-engineering and biomedical imaging applications.

  5. In situ formation of organic-inorganic hybrid nanostructures for photovoltaic applications.

    PubMed

    Wood, Sebastian; Garnett, Oliver; Tokmoldin, Nurlan; Tsoi, Wing C; Haque, Saif A; Kim, Ji-Seon

    2014-01-01

    The performance of hybrid (organic-inorganic) photovoltaic devices is critically dependent on the thin film morphology. This work studies the film formation process using the in situ thermal decomposition of a soluble precursor to form a well-distributed network of CdS nanoparticles within a poly(3-hexylthiophene) (P3HT) polymer matrix. Resonant Raman spectroscopy is used to probe the formation of the inorganic nanoparticles and the corresponding changes in the molecular order of the polymer. We find that the CdS precursor decomposes rapidly upon heating to 160 °C, but that this has a disruptive effect on the P3HT. The extent of this disruption can be controlled by adjusting the annealing temperature, and nanowire aggregates of P3HT are found to have increased susceptibility. Atomic force microscopy reveals that at high temperatures (>200 °C), cracks form in the film, resulting in a 'plateau'-like microstructure. In order to retain the preferable 'granular' microstructure and to control the molecular disruption, low decomposition temperatures are needed. This work identifies a particular problem for optimising the hybrid thin film morphology and shows how it can be partially overcome.

  6. Influence of TiO2 nanostructures on the optical absorption of organic-inorganic perovskite

    NASA Astrophysics Data System (ADS)

    Liu, Zongyi; Ye, Mao; Ostrowski, Michel; Yi, Ya Sha

    2016-04-01

    This work aims to reveal the strong influence of TiO2 nanostructures on the light absorption property of TiO2 and perovskite mixture. Three TiO2 nanostructures, i.e., nanoparticles (S1), ultrapure nanorods (S2), and ultrasmall nanorods (S3), were studied: S1 was selected as a baseline; S2 and S3 were synthesized from S1 by using modified hydrothermal processes. Mesoporous TiO2 thin films were spin-coated from solutions containing these TiO2 nanorods and nanoparticles (S1 as baseline). Organic-inorganic hybrid perovskite CH3NH3PbI3 was then incorporated into these mesoporous TiO2 thin films. Optical absorption results showed that the perovskite mixture with ultrasmall TiO2 nanostructures (S3) has significantly higher optical absorption coefficient. Finite-difference time domain models were built based on three distinct nanostructures of TiO2 and CH3NH3PbI3 mixtures fabricated (S1 to S3) to understand their optical absorption properties. Our work is promising to fabricate TiO2 nanostructures, as a backbone structure, for a series of applications including photovoltaics and photodetection.

  7. Morphological structure of Gluconacetobacter xylinus cellulose and cellulose-based organic-inorganic composite materials

    NASA Astrophysics Data System (ADS)

    Smyslov, R. Yu; Ezdakova, K. V.; Kopitsa, G. P.; Khripunov, A. K.; Bugrov, A. N.; Tkachenko, A. A.; Angelov, B.; Pipich, V.; Szekely, N. K.; Baranchikov, A. E.; Latysheva, E.; Chetverikov, Yu O.; Haramus, V.

    2017-05-01

    Scanning electron microscopy, ultra-small-angle neutron scattering (USANS), small-angle neutron and X-ray scattering (SANS and SAXS), as well as low-temperature nitrogen adsorption, were used in the studies of micro- and mesostructure of polymer matrix prepared from air-dry preliminarily disintegrated cellulose nano-gel film (synthesized by Gluconacetobacter xylinus) and the composites based on this bacterial cellulose. The composites included ZrO2 nanoparticles, Tb3+ in the form of low molecular weight salt and of metal-polymer complex with poly(vinylpyrrolydone)-poly(methacryloyl-o-aminobenzoic acid) copolymer. The combined analysis of the data obtained allowed revealing three levels of fractal organization in mesostructure of G. xylinus cellulose and its composites. It was shown that both the composition and an aggregation state of dopants have a significant impact on the structural characteristics of the organic-inorganic composites. The composites containing Tb3+ ions demonstrate efficient luminescence; its intensity is an order of magnitude higher in the case of the composites with the metal-polymer complex. It was found that there is the optimal content of ZrO2 nanoparticles in composites resulting in increased Tb3+ luminescence.

  8. Mesoporous titania based yolk-shell nanoparticles as multifunctional theranostic platforms for SERS imaging and chemo-photothermal treatment

    NASA Astrophysics Data System (ADS)

    Zhang, Weiwei; Wang, Yunqing; Sun, Xiuyan; Wang, Wenhai; Chen, Lingxin

    2014-11-01

    Recently surface-enhanced Raman scattering (SERS) imaging guided theranostic nanoplatforms have attracted considerable attention. Herein, we developed novel yolk-shell gold nanorod@void@mesoporous titania nanoparticles (AuNR@void@mTiO2 NPs) for simultaneous SERS imaging and chemo-photothermal therapy. Our work showed three highlighted features: first, we proposed a facile and versatile ``up to down'' SERS labeling strategy for the drug delivery system, in which ``empty carriers'' were pre-synthesized, followed by co-loading of Raman reporters on AuNR and anti-cancer drug doxorubicin (DOX) in mTiO2 in sequence. The acquired SERS signal was strong enough for tracking NPs at both living cells and mice levels. Second, we selected mTiO2 as a novel drug loading material instead of the widely used mesoporous silica (mSiO2). The mTiO2 shared satisfactory drug loading and release behavior as mSiO2 but it was chemically inert. This property not only provided a facile way to form a yolk-shell structure but also rendered it with superior structural stability in a biological system. Third, the near infrared (NIR) light absorbing property of the AuNR SERS substrate was also explored for drug release regulation and photothermal treatment. Significantly greater MCF-7 cell killing was observed when treated together with DOX-loaded NPs and NIR laser irradiation, attributable to the synergistic chemo-thermal therapeutic effect. Our results indicated the established SERS labeled yolk-shell NP as a promising theranostic platform and suggested its potential in vivo applications.Recently surface-enhanced Raman scattering (SERS) imaging guided theranostic nanoplatforms have attracted considerable attention. Herein, we developed novel yolk-shell gold nanorod@void@mesoporous titania nanoparticles (AuNR@void@mTiO2 NPs) for simultaneous SERS imaging and chemo-photothermal therapy. Our work showed three highlighted features: first, we proposed a facile and versatile ``up to down'' SERS

  9. High-yield aqueous synthesis of multi-branched iron oxide core-gold shell nanoparticles: SERS substrate for immobilization and magnetic separation of bacteria

    NASA Astrophysics Data System (ADS)

    Tamer, Ugur; Onay, Aykut; Ciftci, Hakan; Bozkurt, Akif Göktuğ; Cetin, Demet; Suludere, Zekiye; Hakkı Boyacı, İsmail; Daniel, Philippe; Lagarde, Fabienne; Yaacoub, Nader; Greneche, Jean-Marc

    2014-10-01

    The high product yield of multi-branched core-shell Fe3- x O4@Au magnetic nanoparticles was synthesized used as magnetic separation platform and surface-enhanced Raman scattering (SERS) substrates. The multi-branched magnetic nanoparticles were prepared by a seed-mediated growth approach using magnetic gold nanospheres as the seeds and subsequent reduction of metal salt with ascorbic acid in the presence of a stabilizing agent chitosan biopolymer and silver ions. The anisotropic growth of nanoparticles was observed in the presence of chitosan polymer matrix resulting in multi-branched nanoparticles with a diameter over 100 nm, and silver ions also play a crucial role on the growth of multi-branched nanoparticles. We propose the mechanism of the formation of multi-branched nanoparticles while the properties of nanoparticles embedded in chitosan matrix are discussed. The surface morphology of nanoparticles was characterized with transmission electron microscopy, scanning electron microscopy, ultraviolet visible spectroscopy (UV-Vis), X-ray diffraction, and fourier transform infrared spectroscopy and 57Fe Mössbauer spectrometry. Additionally, the magnetic properties of the nanoparticles were also examined. We also demonstrated that the synthesized Fe3- x O4@Au multi-branched nanoparticle is capable of targeted separation of pathogens from matrix and sensing as SERS substrates.

  10. Comparison of Fe2O3 and Fe2CoO4 core-shell plasmonic nanoparticles for aptamer mediated SERS assays

    NASA Astrophysics Data System (ADS)

    Marks, Haley; Mabbott, Samuel; Huang, Po-Jung; Jackson, George W.; Kameoka, Jun; Graham, Duncan; Coté, Gerard L.

    2016-03-01

    Conjugation of oligonucleotides or aptamers and their corresponding analytes onto plasmonic nanoparticles mediates the formation of nanoparticle assemblies: molecularly bound bundles of nanoparticles which cause a measurable change in the colloid's optical properties. Here, we present further optimization of a "SERS off" competitive binding assay utilizing plasmonic and magnetic nanoparticles for the detection of the toxin bisphenol A (BPA). The assay involves 1) a `target' silver nanoparticle functionalized with a Raman reporter dye and PEGylated BPA-binding DNA aptamers, and 2) a version of the toxin BPA, bisphenol A diglycidyl ether (BADGE), PEGylated and immobilized onto a silver coated magnetic 'probe' nanoparticle. When mixed, these target and probe nanoparticles cluster into magnetic dimers and trimers and an enhancement in their SERS spectra is observed. Upon introduction of free BPA in its native form, target AgNPs are competitively freed; reversing the nanoparticle assembly and causing the SERS signal to "turn-off" and decrease in response to the competitive binding event. The assay particles were housed inside two types of optofluidic chips containing magnetically active nickel pads, in either a straight or spotted pattern, and both Fe2O3 and Fe2CoO4 were compared as magnetic cores for the silver coated probe nanoparticle. We found that the Ag@ Fe2O3 particles were, on average, more uniform in size and more stable than Ag@ Fe2CoO4, while the addition of cobalt significantly improved the collection time of particles within the magnetic chips. Using 3D Raman mapping, we found that the straight channel design with the Ag@ Fe2O3 particles provided the most uniform nanoparticle organization, while the spotted channel design with Ag@ Fe2CoO4 demonstrated a larger SERS enhancement, and thus a lower limit of detection.

  11. Organic/Inorganic Nano-hybrids with High Dielectric Constant for Organic Thin Film Transistor Applications.

    PubMed

    Yu, Yang-Yen; Jiang, Ai-Hua; Lee, Wen-Ya

    2016-12-01

    The organic material soluble polyimide (PI) and organic-inorganic hybrid PI-barium titanate (BaTiO3) nanoparticle dielectric materials (IBX, where X is the concentration of BaTiO3 nanoparticles in a PI matrix) were successfully synthesized through a sol-gel process. The effects of various BaTiO3 contents on the hybrid film performance and performance optimization were investigated. Furthermore, pentacene-based organic thin film transistors (OTFTs) with PI-BaTiO3/polymethylmethacrylate or cyclic olefin copolymer (COC)-modified gate dielectrics were fabricated and examined. The hybrid materials showed effective dispersion of BaTiO3 nanoparticles in the PI matrix and favorable thermal properties. X-ray diffraction patterns revealed that the BaTiO3 nanoparticles had a perovskite structure. The hybrid films exhibited high formability and planarity. The IBX hybrid dielectric films exhibited tunable insulating properties such as the dielectric constant value and capacitance in ranges of 4.0-8.6 and 9.2-17.5 nF cm(-2), respectively. Adding the modified layer caused the decrease of dielectric constant values and capacitances. The modified dielectric layer without cross-linking displayed a hydrophobic surface. The electrical characteristics of the pentacene-based OTFTs were enhanced after the surface modification. The optimal condition for the dielectric layer was 10 wt% hybrid film with the COC-modified layer; moreover, the device exhibited a threshold voltage of 0.12 V, field-effect mobility of 4.32 × 10(-1) cm(2) V(-1) s(-1), and on/off current of 8.4 × 10(7).

  12. Organic/Inorganic Nano-hybrids with High Dielectric Constant for Organic Thin Film Transistor Applications

    NASA Astrophysics Data System (ADS)

    Yu, Yang-Yen; Jiang, Ai-Hua; Lee, Wen-Ya

    2016-11-01

    The organic material soluble polyimide (PI) and organic-inorganic hybrid PI-barium titanate (BaTiO3) nanoparticle dielectric materials (IBX, where X is the concentration of BaTiO3 nanoparticles in a PI matrix) were successfully synthesized through a sol-gel process. The effects of various BaTiO3 contents on the hybrid film performance and performance optimization were investigated. Furthermore, pentacene-based organic thin film transistors (OTFTs) with PI-BaTiO3/polymethylmethacrylate or cyclic olefin copolymer (COC)-modified gate dielectrics were fabricated and examined. The hybrid materials showed effective dispersion of BaTiO3 nanoparticles in the PI matrix and favorable thermal properties. X-ray diffraction patterns revealed that the BaTiO3 nanoparticles had a perovskite structure. The hybrid films exhibited high formability and planarity. The IBX hybrid dielectric films exhibited tunable insulating properties such as the dielectric constant value and capacitance in ranges of 4.0-8.6 and 9.2-17.5 nF cm-2, respectively. Adding the modified layer caused the decrease of dielectric constant values and capacitances. The modified dielectric layer without cross-linking displayed a hydrophobic surface. The electrical characteristics of the pentacene-based OTFTs were enhanced after the surface modification. The optimal condition for the dielectric layer was 10 wt% hybrid film with the COC-modified layer; moreover, the device exhibited a threshold voltage of 0.12 V, field-effect mobility of 4.32 × 10-1 cm2 V-1 s-1, and on/off current of 8.4 × 107.

  13. SERS and quantum chemical studies on N-methylglycine molecule on silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Parameswari, A.; Mohamed Asath, R.; Premkumar, R.; Milton Franklin Benial, A.

    2017-06-01

    Adsorption characteristics of N-methylglycine (Sar) on silver surface was investigated based on density functional theory and surface enhanced Raman spectroscopy (SERS) technique. The Sar was characterized by powder X-ray diffraction (XRD) and dynamic light scattering techniques. AgNPs were prepared by solution combustion method using urea as fuel. The AgNPs were characterized by XRD and high-resolution transmission electron microscopic techniques. The structural parameters of Sar molecule were compared with the reported experimental XRD values. The change in structural parameters of Sar after adsorption on silver surface shows the interaction between Sar and silver cluster. Raman frequencies were calculated for Sar, Sar adsorbed on silver surface and their corresponding spectra were studied experimentally. The conventional Raman and SERS frequencies were compared with the experimental values and analyzed on the basis of potential energy distribution calculation. Natural bond orbital analysis was carried out to investigate the intra-molecular stabilization interactions, which confirms the bioactivity of the molecule. Frontier molecular orbital analysis was carried out for Sar and Sar adsorbed on silver surface. The reduced band gap value was observed for Sar after adsorption on silver surface. The reduction in band gap indicates the intermolecular charge transfer, which leads to the bioactivity of the title molecule. SERS spectral analysis shows that the Sar adsorbed as stand-on orientation on the silver surface.

  14. Immunoassay for tumor markers in human serum based on Si nanoparticles and SiC@Ag SERS-active substrate.

    PubMed

    Zhou, Lu; Zhou, Jun; Feng, Zhao; Wang, Fuyan; Xie, Shushen; Bu, Shizhong

    2016-04-21

    Based on a sandwich structure consisting of nano-Si immune probes and a SiC@Ag SERS-active immune substrate, a kind of ultra-sensitive immunoassay protocol is presented to detect tumor markers in human serum. The nano-Si immune probes were prepared by immobilizing the detecting antibodies onto the surfaces of SiO2-coated Si nanoparticles (NPs) which were modified with 3-(aminopropyl)trimethoxysilane, and the SiC@Ag SERS-active immune substrates were prepared by immobilizing the captured antibodies on Ag film sputtered on SiC sandpaper. To the best of our knowledge, it is the first time that Si NPs are directly used as Raman tags in an immunoassay strategy. And, the SiC@Ag SERS-active substrates exhibit excellent surface enhanced Raman scattering (SERS) performances with an enhancement factor of ∼10(5), owing to the plasmonic effect of the Ag film on the rough surface of the SiC sandpaper. In our experiments, the sandwich immunoassay structure has been successfully applied to detect prostate specific antigen (PSA), α-fetoprotein (AFP) and carbohydrate antigen 19-9 (CA19-9) in a human serum sample and the limit of detections are as low as 1.79 fg mL(-1), 0.46 fg mL(-1) and 1.3 × 10(-3) U mL(-1), respectively. It reveals that the proposed immunoassay protocol has demonstrated a high sensitivity for tumor markers in human serum and a potential practicability in biosensing and clinical diagnostics.

  15. DNA-embedded Au-Ag core-shell nanoparticles assembled on silicon slides as a reliable SERS substrate.

    PubMed

    Zhang, Zhong; Zhang, Sha; Lin, Mengshi

    2014-05-07

    This study aimed at developing a sensitive and reliable SERS substrate by assembling DNA-embedded Au-Ag core-shell nanoparticles (NPs) on silicon slides. First, a monolayer of well separated DNA-functionalized Au NPs (40 nm) was decorated on (3-aminopropyl)triethoxysilane modified silicon slides. The DNA-embedded Au-Ag core-shell NPs were assembled on the 40 nm Au-DNA NPs to form a core-satellite structure through DNA hybridization. Using 4-MBA as a Raman dye, the SERS performance of the substrates was evaluated after being cleaned by low oxygen and argon plasma. The Raman intensity of the assembly using DNA-embedded Au-Ag core-shell NPs was 8-10 times higher than the intensity of the assembly using Au NPs as satellites. In addition, the signal-to-noise ratio of the assembly was 2.6 times higher than that of a commercial substrate (Klarite™) when a 785 nm laser was used. The SERS enhancements of the assembled substrates were 2.2 to 2.8 times higher than the Klarite when an acquisition time of 5 s was used at an excitation wavelength of 633 nm. The assembled substrates also show a good spot-to-spot and substrate-to-substrate reproducibility at the excitation wavelengths of 633 and 785 nm. These results demonstrate that the fabrication process is simple and cost-effective for assembling DNA-embedded Au-Ag core-shell NPs on silicon slides that can be used as a reliable SERS substrate.

  16. Biomedical Applications of Magnetically Functionalized Organic/Inorganic Hybrid Nanofibers.

    PubMed

    Lee, Hwa-Jeong; Lee, Sang Joon; Uthaman, Saji; Thomas, Reju George; Hyun, Hoon; Jeong, Yong Yeon; Cho, Chong-Su; Park, In-Kyu

    2015-06-15

    Nanofibers are one-dimensional nanomaterial in fiber form with diameter less than 1 µm and an aspect ratio (length/diameter) larger than 100:1. Among the different types of nanoparticle-loaded nanofiber systems, nanofibers loaded with magnetic nanoparticles have gained much attention from biomedical scientists due to a synergistic effect obtained from the unique properties of both the nanofibers and magnetic nanoparticles. These magnetic nanoparticle-encapsulated or -embedded nanofiber systems can be used not only for imaging purposes but also for therapy. In this review, we focused on recent advances in nanofibers loaded with magnetic nanoparticles, their biomedical applications, and future trends in the application of these nanofibers.

  17. Isostructural organic-inorganic hybrid compounds: triethylcholine tribromidocadmate and triethylcholine tribromidomercurate.

    PubMed

    Wang, Dong-Yan; Hou, Xue-Li; Li, Xue-Nan

    2015-08-01

    In order to search for new anionic architectures and develop useful organic-inorganic hybrid materials in halometallate systems, two new crystalline organic-inorganic hybrid compounds have been prepared, i.e. catena-poly[triethyl(2-hydroxyethyl)azanium [[bromidocadmate(II)]-di-μ-bromido

  18. Multifunctional slow-release organic-inorganic compound fertilizer.

    PubMed

    Ni, Boli; Liu, Mingzhu; Lü, Shaoyu; Xie, Lihua; Wang, Yanfang

    2010-12-08

    Multifunctional slow-release organic-inorganic compound fertilizer (MSOF) has been investigated to improve fertilizer use efficiency and reduce environmental pollution derived from fertilizer overdosage. The special fertilizer is based on natural attapulgite (APT) clay used as a matrix, sodium alginate used as an inner coating and sodium alginate-g-poly(acrylic acid-co-acrylamide)/humic acid (SA-g-P(AA-co-AM)/HA) superabsorbent polymer used as an outer coating. The coated multielement compound fertilizer granules were produced in a pan granulator, and the diameter of the prills was in the range of 2.5-3.5 mm. The structural and chemical characteristics of the product, as well as its efficiency in slowing the nutrients release, were examined. In addition, a mathematical model for nutrient release from the fertilizer was applied to calculate the diffusion coefficient D of nutrients in MSOF. The degradation of the SA-g-P(AA-co-AM)/HA coating was assessed by examining the weight loss with incubation time in soil. It is demonstrated that the product prepared by a simple route with good slow-release property may be expected to have wide potential applications in modern agriculture and horticulture.

  19. Hybrid Organic/Inorganic Thiol-ene-Based Photopolymerized Networks

    PubMed Central

    Schreck, Kathleen M.; Leung, Diana; Bowman, Christopher N.

    2011-01-01

    The thiol-ene reaction serves as a more oxygen tolerant alternative to traditional (meth)acrylate chemistry for forming photopolymerized networks with numerous desirable attributes including energy absorption, optical clarity, and reduced shrinkage stress. However, when utilizing commercially available monomers, many thiol-ene networks also exhibit decreases in properties such as glass transition temperature (Tg) and crosslink density. In this study, hybrid organic/inorganic thiol-ene resins incorporating silsesquioxane (SSQ) species into the photopolymerized networks were investigated as a route to improve these properties. Thiol- and ene-functionalized SSQs (SH-SSQ and allyl-SSQ, respectively) were synthesized via alkoxysilane hydrolysis/condensation chemistry, using a photopolymerizable monomer [either pentaerythriol tetrakis(3-mercaptopropionate) (PETMP) or 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TATATO)] as the reaction solvent. The resulting SSQ-containing solutions (SSQ-PETMP and SSQ-TATATO) were characterized, and their incorporation into photopolymerized networks was evaluated. PMID:21984847

  20. Optical Spintronics in Organic-Inorganic Perovskite Photovoltaics.

    PubMed

    Li, Junwen; Haney, Paul M

    2016-04-15

    Organic-inorganic halide CH3NH3PbI3 solar cells have attracted enormous attention in recent years due to their remarkable power conversion efficiency. When inversion symmetry is broken, these materials should exhibit interesting spin-dependent properties as well, owing to their strong spin-orbit coupling. In this work, we consider the spin-dependent optical response of CH3NH3PbI3. We first use density functional theory to compute the ballistic spin current generated by absorption of unpolarized light. We then consider diffusive transport of photogenerated charge and spin for a thin CH3NH3PbI3 layer with a passivated surface and an Ohmic, non-selective contact. The spin density and spin current are evaluated by solving the drift-diffusion equations for a simplified 3-dimensional Rashba model of the electronic structure of the valence and conduction bands. We provide analytic expressions for the photon flux required to induce measurable spin densities, and propose that these spin densities can provide useful information about the role of grain boundaries in the photovoltaic behavior of these materials. We also discuss the prospects for measuring the optically generated spin current with the inverse spin Hall effect.

  1. Optical Spintronics in Organic-Inorganic Perovskite Photovoltaics

    PubMed Central

    Li, Junwen; Haney, Paul M.

    2016-01-01

    Organic-inorganic halide CH3NH3PbI3 solar cells have attracted enormous attention in recent years due to their remarkable power conversion efficiency. When inversion symmetry is broken, these materials should exhibit interesting spin-dependent properties as well, owing to their strong spin-orbit coupling. In this work, we consider the spin-dependent optical response of CH3NH3PbI3. We first use density functional theory to compute the ballistic spin current generated by absorption of unpolarized light. We then consider diffusive transport of photogenerated charge and spin for a thin CH3NH3PbI3 layer with a passivated surface and an Ohmic, non-selective contact. The spin density and spin current are evaluated by solving the drift-diffusion equations for a simplified 3-dimensional Rashba model of the electronic structure of the valence and conduction bands. We provide analytic expressions for the photon flux required to induce measurable spin densities, and propose that these spin densities can provide useful information about the role of grain boundaries in the photovoltaic behavior of these materials. We also discuss the prospects for measuring the optically generated spin current with the inverse spin Hall effect. PMID:27453958

  2. Ion Dynamics in Organic-Inorganic Composite Superionic Conductor Glasses

    SciTech Connect

    Asayama, Ryo; Kuwata, Naoaki; Kawamura, Junichi

    2006-05-05

    Ionic conductivity of organic-inorganic composite superionic conductor glasses composed of AgI and alkylammoniumiodides is measured as a function of frequency, temperature and composition. A clear transition from insulator to superionic conductor is confirmed at the volume fraction {phi} of AgI is about 35 %. The dc component of the conductivity is fitted to the {sigma}{approx}({phi}-{phi}c){mu} with {phi}c=0.36, {mu}=2.5 for the present data. Near the percolation threshold, a power-law type frequency dependence of {omega}n (n{approx}0.67) is seen in mid frequency and {omega}1.0 at higher frequency corresponding to the constant loss region power-law is observed. The activation energies and preexponential factors derived from the temperature dependence increase from 0.3 to 0.7 eV approaching to the threshold. From these results, the ion dynamics in these glasses can be explained by the static site percolation theory at first approximation, but require the consideration on the chemical bond variation between the Ag and I modified by the organic ions.

  3. Optical spintronics in organic-inorganic perovskite photovoltaics

    NASA Astrophysics Data System (ADS)

    Li, Junwen; Haney, Paul M.

    2016-04-01

    Organic-inorganic halide CH3NH3PbI3 solar cells have attracted enormous attention in recent years due to their remarkable power conversion efficiency. When inversion symmetry is broken, these materials should exhibit interesting spin-dependent properties as well, owing to their strong spin-orbit coupling. In this work, we consider the spin-dependent optical response of CH3NH3PbI3 . We first use density functional theory to compute the ballistic spin current generated by absorption of unpolarized light. We then consider diffusive transport of photogenerated charge and spin for a thin CH3NH3PbI3 layer with a passivated surface and an Ohmic, nonselective contact. The spin density and spin current are evaluated by solving the drift-diffusion equations for a simplified three-dimensional Rashba model of the electronic structure of the valence and conduction bands. We provide analytic expressions for the photon flux required to induce measurable spin densities, and propose that these spin densities can provide useful information about the role of grain boundaries in the photovoltaic behavior of these materials. We also discuss the prospects for measuring the optically generated spin current with the inverse spin Hall effect.

  4. Polyoxometalate-Based Organic-Inorganic Hybrids as Antitumor Drugs.

    PubMed

    Fu, Lei; Gao, Hanqin; Yan, Mei; Li, Shouzhu; Li, Xinyu; Dai, Zhifei; Liu, Shaoqin

    2015-06-24

    Polyoxometalates (POMs) have shown encouraging antitumor activity. However, their cytotoxicity in normal cells and unspecific interactions with biomolecules are two major obstacles that impede the practical applications of POMs in clinical cancer treatment. Derivatization of POMs with more biocompatible organic ligands is expected to cause a synergetic effect and achieve improved bioactivity and biospecificity. Herein, the synthesis of an amphiphilic organic-inorganic hybrid is reported by grafting a long-chain organoalkoxysilane lipid onto a POM. The amphiphilic POM hybrid could spontaneously assemble into the vesicles and exhibits enhanced antitumor activity for human colorectal cancer cell lines (HT29) compared to that of parent POMs. This detailed study reveals that the amphiphilic nature of POM hybrids enables the as-formed vesicles to easily bind to the cell membranes and then be uptaken by the cells, thus leading to a substantial increase in antitumor activity. Such prominent antitumor action is mostly accomplished via cell apoptosis, which ultimately results in cell death. Our finding demonstrates that novel POM hybrids-based drugs with increased bioactivity could be obtained by decorating POMs with selective organic ligands. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Laser Crystallization of Organic-Inorganic Hybrid Perovskite Solar Cells.

    PubMed

    Jeon, Taewoo; Jin, Hyeong Min; Lee, Seung Hyun; Lee, Ju Min; Park, Hyung Il; Kim, Mi Kyung; Lee, Keon Jae; Shin, Byungha; Kim, Sang Ouk

    2016-08-23

    Organic-inorganic hybrid perovskites attract enormous research interest for next generation solar energy harvest. Synergistic crystalline structures comprising organic and inorganic components enable solution processing of perovskite films. A reliable crystallization method for perovskites, compatible with fast continuous process over large-area flexible substrates, is crucial for high performance solar cell production. Here, we present laser crystallization of hybrid perovskite solar cells using near-infrared (NIR) laser (λ = 1064 nm). Crystalline morphology of CH3NH3PbI3 (MAPbI3) perovskite films are widely controllable with laser irradiation condition while maintaining film uniformity. Photothermal heating effectively assisted by interfacial photoconversion layers is critical for phase transformation without beam damage of multilayered device structures. Notably, laser crystallization attains higher device performances than conventional thermal annealing. Fast laser crystallization with manufacture level scan rate (1 m min(-1)) demonstrates inverted-type perovskite solar cells with 11.3 and 8.0% efficiencies on typical glass and flexible polymer substrates, respectively, without rigorous device optimization.

  6. Gold and silver nanoparticle monomers are non-SERS-active: a negative experimental study with silica-encapsulated Raman-reporter-coated metal colloids.

    PubMed

    Zhang, Yuying; Walkenfort, Bernd; Yoon, Jun Hee; Schlücker, Sebastian; Xie, Wei

    2015-09-07

    Noble metal nanoparticles (NPs) are the most commonly employed plasmonic substrates in surface-enhanced Raman scattering (SERS) experiments. Computer simulations show that monomers of Ag and Au nanocrystals ("spherical" NPs) do not exhibit a notable plasmonic enhancement, i.e., they are essentially non-SERS-active. However, in experiments, SERS enhanced by spherical NP colloids has been frequently reported. This implies that the monomers do not have strong SERS activity, but detectable enhancement should more or less be there. Because of the gap between theory and practice, it is important to demonstrate experimentally how SERS-active the metal colloid actually is and, in case a SERS signal is observed, where it originates from. In particular the aggregation of the colloid, induced by high centrifugal forces in washing steps or due to a harsh ionic environment of the suspension medium, should be controlled since it is the very high SERS activity of NP clusters which dominates the overall SERS signal of the colloid. We report here the experimental evaluation of the SERS activity of 80 nm Au and Ag NP monomers. Instead of showing fancy nanostructures and super SERS enhancement, we present the method on how to obtain negative experimental data. In this approach, no SERS signal was obtained from the colloid with a Raman reporter on the metal surface when the NPs were encapsulated carefully within a thick silica shell. Without silica encapsulation, if a very low centrifugation speed is used for the washing steps, only a negligible SERS signal can be detected even at very high NP concentrations. In contrast, strong SERS signals can be detected when the NPs are suspended in acidic solutions. These results indicate that Au and Ag NP monomers essentially exhibit no SERS activity of practical relevance.

  7. Rapid fabrication of silver nanoparticle-coated filter paper as SERS substrate for low-abundance molecules detection

    NASA Astrophysics Data System (ADS)

    Wei, Wenxian; Huang, Qingli

    2017-05-01

    Silver nanoparticles (Ag NPs) were fabricated on the fibers of the filter paper by the reaction between silver nitrate (AgNO3) and hydrazine hydrate (N2H4·H2O). By using the Ag NPs-coated paper, the limit of detection as low as 10- 11 M for Rhodamine B (RhB) and 10- 10 M for crystal violet (CV) was achieved. Moreover, the uniformity, reproducibility and stability of the Ag NPs-coated paper were also involved. Meanwhile, the detection of 10- 4-10- 6 M moxifloxacin in deionized water and tap water was also carried out successfully by using the paper-based substrates. The fabrication process is easy to handle, cost-efficient and the as-prepared paper-based SERS substrate is ideal for rapid and simple detection of low-abundance molecules.

  8. SERS Taper-Fiber Nanoprobe Modified by Gold Nanoparticles Wrapped with Ultrathin Alumina Film by Atomic Layer Deposition.

    PubMed

    Xu, Wenjie; Chen, Zhenyi; Chen, Na; Zhang, Heng; Liu, Shupeng; Hu, Xinmao; Wen, Jianxiang; Wang, Tingyun

    2017-02-25

    A taper-fiber SERS nanoprobe modified by gold nanoparticles (Au-NPs) with ultrathin alumina layers was fabricated and its ability to perform remote Raman detection was demonstrated. The taper-fiber nanoprobe (TFNP) with a nanoscale tip size under 80 nm was made by heated pulling combined with the chemical etching method. The Au-NPs were deposited on the TFNP surface with the electrostatic self-assembly technology, and then the TFNP was wrapped with ultrathin alumina layers by the atomic layer deposition (ALD) technique. The results told us that with the increasing thickness of the alumina film, the Raman signals decreased. With approximately 1 nm alumina film, the remote detection limit for R6G aqueous solution reached 10(-6) mol/L.

  9. SERS Taper-Fiber Nanoprobe Modified by Gold Nanoparticles Wrapped with Ultrathin Alumina Film by Atomic Layer Deposition

    PubMed Central

    Xu, Wenjie; Chen, Zhenyi; Chen, Na; Zhang, Heng; Liu, Shupeng; Hu, Xinmao; Wen, Jianxiang; Wang, Tingyun

    2017-01-01

    A taper-fiber SERS nanoprobe modified by gold nanoparticles (Au-NPs) with ultrathin alumina layers was fabricated and its ability to perform remote Raman detection was demonstrated. The taper-fiber nanoprobe (TFNP) with a nanoscale tip size under 80 nm was made by heated pulling combined with the chemical etching method. The Au-NPs were deposited on the TFNP surface with the electrostatic self-assembly technology, and then the TFNP was wrapped with ultrathin alumina layers by the atomic layer deposition (ALD) technique. The results told us that with the increasing thickness of the alumina film, the Raman signals decreased. With approximately 1 nm alumina film, the remote detection limit for R6G aqueous solution reached 10−6 mol/L. PMID:28245618

  10. Rapid fabrication of silver nanoparticle-coated filter paper as SERS substrate for low-abundance molecules detection.

    PubMed

    Wei, Wenxian; Huang, Qingli

    2017-05-15

    Silver nanoparticles (Ag NPs) were fabricated on the fibers of the filter paper by the reaction between silver nitrate (AgNO3) and hydrazine hydrate (N2H4·H2O). By using the Ag NPs-coated paper, the limit of detection as low as 10(-11)M for Rhodamine B (RhB) and 10(-10)M for crystal violet (CV) was achieved. Moreover, the uniformity, reproducibility and stability of the Ag NPs-coated paper were also involved. Meanwhile, the detection of 10(-4)-10(-6)M moxifloxacin in deionized water and tap water was also carried out successfully by using the paper-based substrates. The fabrication process is easy to handle, cost-efficient and the as-prepared paper-based SERS substrate is ideal for rapid and simple detection of low-abundance molecules.

  11. Different behaviour of molecules in dark SERS state on colloidal Ag nanoparticles estimated by truncated power law analysis of blinking SERS.

    PubMed

    Kitahama, Yasutaka; Araki, Daichi; Yamamoto, Yuko S; Itoh, Tamitake; Ozaki, Yukihiro

    2015-09-07

    For single colloidal Ag nanoaggregates, covered with either large or small amounts of citrate anions, blinking surface-enhanced Raman scattering (SERS) of anionic thiacyanine was measured and analyzed by a truncated power law. The power law without and with an exponential function reproduces a probability distribution for bright and dark SERS events versus their duration times, respectively. On the Ag surface, except for junctions of the nanoaggregate with a large or small amount of the citrate anions, two-dimensional fast or one-dimensional slow random walk of the anionic thiacyanine, respectively, was estimated by the exponents and the truncation times in the power law for the dark SERS events. In addition, the power law exponents for the bright SERS events were derived to be of similar values, indicating a similar molecular random walk near the junction, which may be dominated evenly by a surface-plasmon-enhanced electromagnetic field on the same-sized Ag nanoaggregate. Thus, not only the bright SERS, but also the dark SERS molecular behaviour on the Ag surface was investigated by the truncated power law analysis.

  12. Virus shaped gold nanoparticles with tunable near infrared plasmon as SERS substrates

    NASA Astrophysics Data System (ADS)

    Jiji, S. G.; Gopchandran, K. G.

    2015-07-01

    A facile seed mediated strategy for the synthesis of virus shaped gold nanoparticles (AuNPs) with plasmon band tunable from 650 to 1200 nm is reported. Compared to other works, a very low concentration of 0.01 mM of the precursor HAuCl4 is used in this work. Amount of the weak reducing agent modifies both the size and shape of the nanoparticles. This is a single-root synthesis for the growth and formation of gold polyhedral like nanoparticles, spiky nanostars and nanoflowers, resembling the shape of viruses. The longitudinal plasmon was found to shift towards infrared with increase in the length of spikes in the nanostars. The maximum length of these spikes obtained in this synthesis was ∼65 nm. A substantial red-shift was observed in the plasmon characteristics of nanoflowers compared to that of spherical AuNPs of the same size, indicating plasmon hybridization. The use of nanoflowers and spiky nanostars were tested with three different probe molecules viz., azure a chloride, nile blue chloride (NBC) and crystal violet. The Raman enhancement was of the order of ∼1012 with NBC molecules, when nanoflowers were used as substrates and this towering of Raman signal is attributed to the closeness to ‘pre-resonance’. A re-branching of spikes due to twinning of spike edges in the nanostars grown under optimum conditions were observed and are described as hotspots causing high amplification of Raman signals in the surface enhanced Raman spectroscopy spectra. Investigations on the influence of incubation time on the Raman enhancement of the molecules varies with incubation time.

  13. Boat-like Au nanoparticles embedded mesoporous γ-Al2O3 films: an efficient SERS substrate

    NASA Astrophysics Data System (ADS)

    Dandapat, Anirban; Pramanik, Sourav; Bysakh, Sandip; De, Goutam

    2013-07-01

    Boat-like Au nanoparticles (NPs) have been synthesized within the mesoporous γ-Al2O3 films. First, mesoporous γ-Al2O3 film was prepared using aluminum alkoxide derived boehmite sol in the presence of CTAB as structure directing agent. The film was heat-treated at 500 °C to obtain γ-Al2O3 film with an average pore diameter of 4.3 nm. HAuCl4 solution was then soaked into the porous film followed by heat-treatment at 500 °C to generate Au NPs. The blue-colored films so obtained were characterized by UV-visible spectroscopy, grazing incidence X-ray diffraction, FESEM, and TEM studies. FESEM and TEM studies reveal the formation boat-like Au NPs in γ-Al2O3 film matrix. Cross-sectional FESEM shows the thickness of the films to be 2.2 μm. These nanocomposite films were used as a unique surface-enhanced Raman scattering (SERS) substrate for easy detection of low concentration (10-8 M) analyte (methylene blue) molecule. Boat-like shape of Au NPs have several edges and junctions that contain high density of hotspots to exhibit very high SERS signals. Due to such shape of Au NPs, the films also show strong absorption in the visible-NIR region that would extend the use of the films in heat-absorbing and biomedical applications.

  14. Organic-Inorganic Hybrids Using Novel Phenylethynyl Imide Silanes

    NASA Technical Reports Server (NTRS)

    Park, C.; Lowther, S. E.; Smith, J. G., Jr.

    2001-01-01

    In this presentation, polyimide-silica hybrids using novel phenylethynyl imide silanes are reported. The phenylethynyl group is present in the organic precursor as either a pendent or an end group to bond chemically with the polyimide adhesive containing phenylethynyl groups during processing, while the silane group of the organic precursor would chemically react with the inorganic precursor through oxane bond formation. The chemical compositions of these novel hybrids were examined using X-ray mapping modes of scanning electron microscopy (SEM), which revealed a silicon gradient interphase between the high surface energy substrate and the polyimide adhesive. Novel aromatic phenylethynyl imide silanes (APEISs) and pendent phenylethynyl imide oligomeric disilanes (PPEIDSs) have been synthesized, and sol-gel solutions containing the new silanes, a phenylethynyl terminated imide oligomer (PETI-5), and an inorganic precursor were formulated to develop a gradient hybrid interphase between a titanium alloy and the adhesive. Two different sol-gel systems were investigated to develop organic-inorganic hybrids. Hybrid I was composed of an organic precursor containing both phenylethynyl and silane groups (PPEIDS) and an inorganic precursor. Functional group concentrations were controlled by the variation of the molecular weight of the imide backbone of PPEIDS. Hybrid II was composed of organic and inorganic precursors and a coupling agent containing both phenylethynyl and silane groups. Morphology and chemical composition of the hybrid interphase between the inorganic substrate and the adhesive were investigated, and the bond strength and durability were evaluated using lap shear tests at various conditions. The assessment of how the bonding at an interface is affected by various sol-gel solution compositions and environments is reported.

  15. Aerosol-based fabrication of biocompatible organic-inorganic nanocomposites.

    PubMed

    Byeon, Jeong Hoon; Roberts, Jeffrey T

    2012-05-01

    Several novel nanoparticle composites were conveniently obtained by appropriately reacting freshly produced aerosol metal nanoparticles with soluble organic components. A serial reactor consisting of a spark particle generator coupled to a collison atomizer was used to fabricate the new materials, which included nanomagnetosols (comprising iron nanoparticles, the drug ketoprofen, and a Eudragit shell), hybrid nanogels (comprising iron nanoparticles and an N-isopropylacrylamide, NIPAM, gel), and nanoinorganics (gold immobilized silica). A fourth hybrid material, consisting of iron-gold nanoparticles and NIPAM) was obtained via an aerosol into liquid configuration, in which aerosol iron-gold particles were collected into a NIPAM/ethanol solution and then formed into nanogels with NIPAM under ultrasonic treatment. The strategy outlined in this work is potentially generalizable as a new platform for creating biocompatible nanocomposites, using only clinically approved starting materials in a single pass and under low-temperature conditions.

  16. Biomedical Applications of Magnetically Functionalized Organic/Inorganic Hybrid Nanofibers

    PubMed Central

    Lee, Hwa-Jeong; Lee, Sang Joon; Uthaman, Saji; Thomas, Reju George; Hyun, Hoon; Jeong, Yong Yeon; Cho, Chong-Su; Park, In-Kyu

    2015-01-01

    Nanofibers are one-dimensional nanomaterial in fiber form with diameter less than 1 µm and an aspect ratio (length/diameter) larger than 100:1. Among the different types of nanoparticle-loaded nanofiber systems, nanofibers loaded with magnetic nanoparticles have gained much attention from biomedical scientists due to a synergistic effect obtained from the unique properties of both the nanofibers and magnetic nanoparticles. These magnetic nanoparticle-encapsulated or -embedded nanofiber systems can be used not only for imaging purposes but also for therapy. In this review, we focused on recent advances in nanofibers loaded with magnetic nanoparticles, their biomedical applications, and future trends in the application of these nanofibers. PMID:26084046

  17. Effect of Interface energy and electron transfer on shape, plasmon resonance and SERS activity of supported surfactant-free gold nanoparticles

    SciTech Connect

    Giangregorio, Maria M.; Dastmalchi, Babak; Suvorova, Alexandra; Bianco, Giuseppe V.; Hingerl, Kurt; Bruno, Giovanni; Losurdo, Maria

    2014-01-01

    For device integration purposes plasmonic metal nanoparticles must be supported/deposited on substrates. Therefore, it is important to understand the interaction between surfactant-free plasmonic metal nanoparticles and different substrates, as well as to identify factors that drive nanoparticles nucleation and formation. Here we show that for nanoparticles grown directly on supports, the substrate/nanoparticle interfacial energy affects the equilibrium shape of nanoparticles. Therefore, oblate, spherical and prolate Au nanoparticles (NPs) with different shapes have been deposited by radiofrequency sputtering on substrates with different characteristics, namely a dielectric oxide Al2O3 (0001), a narrow bandgap semiconductor Si (100), and a polar piezoelectric wide bandgap semiconductor 4H–SiC (0001). We demonstrate that the higher the substrate surface energy, the higher the interaction with the substrate, resulting in flat prolate Au nanoparticles. The resulting localized surface plasmon resonance characteristics of Au NPs/Al2O3, Au NPs/Si and Au NPs/SiC have been determined by spectroscopic ellipsometry and correlated with their structure and shape studied by transmission electron microscopy. Finally, we have demonstrated the diverse response of the tailored plasmonic substrates as ultrasensitive SERS chemical sensors. Flat oblates Au NPs on SiC result in an enhanced and more stable SERS response. The experimental findings are validated by numerical simulations of electromagnetic fields.

  18. Nanostructured organic/inorganic semicondutor photovoltaics: Investigation on morphology and optoelectronics performance

    NASA Astrophysics Data System (ADS)

    Wanninayake, Aruna Pushpa Kumara

    Organic solar cell is a promising technology because of the versatility of organic materials in terms of tunability of their electrical and optical properties. In addition, their relative insensitivity to film imperfections potentially allows for very low-cost high-throughput roll-to-roll processing. However, the power conversion efficiency of organic solar cell is still limited and needs to be improved in order to be competitive with grid parity. This work is focused on the design and characterization of a new organic/inorganic hybrid device to enhance the efficiency factors of bilayer organic solar cells such as: light absorption, exciton diffusion, exciton dissociation, charge transportation and charge collection at the electrodes. In a hybrid solar cell operation, external quantum efficiency is determined by these five factors. The external quantum efficiency has linear relationship to the power conversation efficiency via short circuit current density. Bulk heterojunction (BHJ) PSCs benefit from a homogeneous donor-acceptor (D-A) contact interface compared to their inorganic counterpart. A homogenous D-A interface offers a longer free path for charge carriers, resulting in a longer diffusional pathway and a larger coulomb interaction between electrons and holes. This is triggered by the low dielectric constant of organic semiconductors. Among various conventional donor-acceptor structures, poly(3-hexylthiophene)/[6,6]-phenyl-C70-butyric acid methyl ester (P3HT/PCBM) mixture is the most promising and ideal donor-acceptor pair due to their unique properties. In order to take benefits from both organic and inorganic materials, inorganic nanoparticles are incorporated in this donor-acceptor polymer structure. Light trapping enhances light absorption and increases efficiencies with thinner device structure. In this study, copper oxide nanoparticles are used in the P3HT/PC70BM active layer to optimize the optical absorption properties in the blend. In addition, zinc

  19. Smart Liquid SERS Substrates based on Fe3O4/Au Nanoparticles with Reversibly Tunable Enhancement Factor for Practical Quantitative Detection

    NASA Astrophysics Data System (ADS)

    Hu, Fei; Lin, Haiyang; Zhang, Zhaoshun; Liao, Fan; Shao, Mingwang; Lifshitz, Yeshayahu; Lee, Shuit-Tong

    2014-11-01

    There is a strong correlation between the surface enhanced Raman scattering (SERS) enhancement factor (EF), the excitation wavelength, and the feature properties (composition, size, geometry, and analytes). The prediction of the EF of specific substrates, crucial to the quantitative SERS detection, is however still very difficult. The present work presents smart liquid SERS substrates consisting of suspensions of Fe3O4/Au nanoparticles, which provide high spot-to-spot uniformity, reproducibility and good reversibility. The EF of these substrates can be reversibly tuned by applying an external magnetic field. The EF magnetic tuning is within 2 orders of magnitude per substrate in the range of 104-107. The ability to reversibly adjust the SERS EF enables to reduce EF variations caused by external effects such as substrate-to-substrate differences and long-term-storage degradation. This improves the quantitative detection of analytes and might be a significant step forward in employing SERS for practical applications.

  20. Smart Liquid SERS Substrates based on Fe3O4/Au Nanoparticles with Reversibly Tunable Enhancement Factor for Practical Quantitative Detection

    PubMed Central

    Hu, Fei; Lin, Haiyang; Zhang, Zhaoshun; Liao, Fan; Shao, Mingwang; Lifshitz, Yeshayahu; Lee, Shuit-Tong

    2014-01-01

    There is a strong correlation between the surface enhanced Raman scattering (SERS) enhancement factor (EF), the excitation wavelength, and the feature properties (composition, size, geometry, and analytes). The prediction of the EF of specific substrates, crucial to the quantitative SERS detection, is however still very difficult. The present work presents smart liquid SERS substrates consisting of suspensions of Fe3O4/Au nanoparticles, which provide high spot-to-spot uniformity, reproducibility and good reversibility. The EF of these substrates can be reversibly tuned by applying an external magnetic field. The EF magnetic tuning is within 2 orders of magnitude per substrate in the range of 104–107. The ability to reversibly adjust the SERS EF enables to reduce EF variations caused by external effects such as substrate-to-substrate differences and long-term-storage degradation. This improves the quantitative detection of analytes and might be a significant step forward in employing SERS for practical applications. PMID:25428185

  1. Relationship Between Interfacial Strength and Materials Properties in Hybrid Organic/Inorganic Nanomaterials

    NASA Astrophysics Data System (ADS)

    Snyder, Chad; Richardson, Mickey; Zhou, Jing; Holmes, Gale; Karim, Alamgir; D'Souza, Nandika

    2008-03-01

    Thermal interface materials (TIM's) are critical to the semiconductor electronics industry for heat dissipation, a potential show-stopper for future technology nodes. Essentially, an epoxy nanocomposite, TIMs suffer from a series of typical nanocomposite limitations including heat conduction in nanoscale inclusions, nanoparticle dispersion, void formation with thermal cycling, and interfacial resistance between the matrix and filler. It is postulated that the interfacial adhesion between the matrix and nanofiller is at the root cause of many of these difficulties, however, few techniques exist to characterize this critical property. Compounding this are the overall difficulties associated with characterizing these materials in their ultimate applications, i.e., thin films. To this end, a novel series of organic/inorganic hybrid nanostructured materials based on layered double hydroxides in epoxy matrices were designed as a test bed to develop the measurement techniques needed to elucidate the relationship between the material structure and dynamics and the ultimate materials properties. Initial results are presented based on characterization by mechanical, dielectric, and thermal spectroscopies.

  2. Ag-In-Zn-S quantum dots for hybrid organic-inorganic solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Eung-min; Ruankham, Pipat; Lee, Jae-hyeong; Hachiya, Kan; Sagawa, Takashi

    2016-02-01

    Quantum dots of (AgIn)xZn2(1-x)S2 (x = 0.6, 0.8, and 1.0) capped by oleylamine were prepared and applied for hybrid organic-inorganic solar cells consisting of glass-indium-tin-oxide/ZnO/(AgIn)xZn2(1-x)S2/poly(3-hexylthiophene)/MoO3/Ag. The short-circuit current density (Jsc) and open-circuit voltage (Voc) of the hybrid solar cells were measured, and we found a low power conversion efficiency (PCE) below 0.1%. From the incident photon-to-current efficiency (IPCE) profiles of the hybrid devices, there is no marked photocurrent generation from 350 to 700 nm, which is ascribed to the absorption region of (AgIn)xZn2(1-x)S2. To improve the photovoltaic performance, ligand substitution from oleylamine to pyridine was performed. The PCE of the hybrid cell using the pyridine-capped (AgIn)xZn2(1-x)S2 was improved twofold in terms of both Jsc and Voc as compared with that of the oleylamine-capped one. In particular, from the IPCE measurements, a remarkable (more than doubled) enhancement of photocurrent generation from 400 to 450 nm was observed with the pyridine-substituted nanoparticles.

  3. Organometallic Iridium Complex Containing a Dianionic, Tridentate, Mixed Organic-Inorganic Ligand.

    PubMed

    Bloomfield, Aaron J; Matula, Adam J; Mercado, Brandon Q; Batista, Victor S; Crabtree, Robert H

    2016-08-15

    A pentamethylcyclopentadienyl-iridium complex containing a tricyclic, dianionic, tridentate, scorpionate (facial binding), mixed organic-inorganic ligand was synthesized and characterized by single-crystal X-ray crystallography, as well as polynuclear NMR, UV-vis, and IR spectroscopies. The central cycle of the tridentate ligand consists of a modified boroxine in which two of the boron centers are tetrahedral, anionic borates. The complex is stable to hydrolysis in aqueous solution for >9 weeks at 25 °C but reacts with a 50 mM solution of sodium periodate within 12 s to form a periodate-driven oxygen evolution catalyst that has a turnover frquency of >15 s(-1). However, the catalyst is almost completely deactivated within 5 min, achieving an average turnover number of ca. 2500 molecules of oxygen per atom of iridium. Nanoparticles were not observed on this time scale but did form within 4 h of catalyst activation under these experimental conditions. The parent complex was modeled using density functional theory, which accurately reflected the geometry of the complex and indicated significant interaction of iridium- and boracycle-centered orbitals.

  4. Chloride ion-assisted self-assembly of silver nanoparticles on filter paper as SERS substrate

    NASA Astrophysics Data System (ADS)

    Hasi, Wu-Li-Ji; Lin, Xiang; Lou, Xiu-Tao; Lin, Shuang; Yang, Fang; Lin, Dian-Yang; Lu, Zhi-Wei

    2015-03-01

    In this work, a robust and easy-to-handle strategy was developed to fabricate silver nanoparticles (Ag NPs)-decorated filter paper as surface-enhanced Raman spectroscopy substrate using dip-coating method only with the assistance of chloride ions. Filter paper was modified with chloride ions for chemisorption of Ag NPs, overcoming the electrostatic repulsion between Ag NPs and paper. The effect of laser-induced substrate deformation was studied. The enhancement factor of the substrate was higher than 6.4 × 105 with a limit of detection of 1 × 10-8 M for 4-mercaptobenzoic acid. The Ag NPs-decorated paper substrate exhibits a good uniformity and can be stored for more than 2 months with negligible degradation. This substrate has great potential for detecting food contaminations, environment polluters and biomolecules.

  5. Chitosan-coated triangular silver nanoparticles as a novel class of biocompatible, highly sensitive plasmonic platforms for intracellular SERS sensing and imaging

    NASA Astrophysics Data System (ADS)

    Potara, Monica; Boca, Sanda; Licarete, Emilia; Damert, Annette; Alupei, Marius-Costel; Chiriac, Mircea T.; Popescu, Octavian; Schmidt, Ute; Astilean, Simion

    2013-06-01

    There is a need for new strategies for noninvasive imaging of pathological conditions within the human body. The approach of combining the unique physical properties of noble-metal nanoparticles with their chemical specificity and an easy way of conjugation open up new routes toward building bio-nano-objects for biomedical tracking and imaging. This work reports the design and assessment of a novel class of biocompatible, highly sensitive SERS nanotags based on chitosan-coated silver nanotriangles (Chit-AgNTs) labeled with para-aminothiophenol (p-ATP). The triangular nanoparticles are used as Raman scattering enhancers and have proved to yield a reproducible and strong SERS signal. When tested inside lung cancer cells (A549) this class of SERS nanotags presents low in vitro toxicity, without interfering with cell proliferation. Easily internalized by the cells, as demonstrated by imaging using both reflected bright-light optical microscopy and SERS spectroscopy, the particles are proved to be detectable inside cells under a wide window of excitation wavelengths, ranging from visible to near infrared (NIR). Their high sensitivity and NIR availability make this class of SERS nanotags a promising candidate for noninvasive imaging of cancer cells.There is a need for new strategies for noninvasive imaging of pathological conditions within the human body. The approach of combining the unique physical properties of noble-metal nanoparticles with their chemical specificity and an easy way of conjugation open up new routes toward building bio-nano-objects for biomedical tracking and imaging. This work reports the design and assessment of a novel class of biocompatible, highly sensitive SERS nanotags based on chitosan-coated silver nanotriangles (Chit-AgNTs) labeled with para-aminothiophenol (p-ATP). The triangular nanoparticles are used as Raman scattering enhancers and have proved to yield a reproducible and strong SERS signal. When tested inside lung cancer cells (A549

  6. Organic-inorganic hybrid superhydrophobic surfaces using methyltriethoxysilane and tetraethoxysilane sol-gel derived materials in emulsion

    NASA Astrophysics Data System (ADS)

    Wen, Xiu-Fang; Wang, Kun; Pi, Pi-Hui; Yang, Jin-Xin; Cai, Zhi-Qi; Zhang, Li-juan; Qian, Yu; Yang, Zhuo-Ru; Zheng, Da-feng; Cheng, Jiang

    2011-11-01

    By applying alkaline-catalyzed co-hydrolysis and copolycondensation reactions of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) in organic siloxane modified polyacrylate emulsion (OSPA emulsion), we are able to demonstrate the potential for developing a sol-gel derived organic-inorganic hybrid emulsion for a superhydrophobic surface research. TEOS and MTES derived sol-gel moieties can be designed for a physical roughness and hydrophobic characteristic (Si-CH3) of the hybrid superhydrophobic surface, while OSPA emulsion can be endowed for good film-forming property. The effect of formulation parameters on superhydrophobicity and film-forming property was analyzed. The water contact angle (WCA) on the sol-gel derived hybrid film is determined to be 156°, and the contact angle hysteresis is 5° by keeping the mole ratio of TEOS:MTES:C2H5OH:NH3·H2O:AMP-95 at 1:4:30:10:0.63 and the mass percentage of OSPA emulsion at 25%. The nanoparticle-based silica rough surface is observed as the mole ratio of MTES/TEOS at 4:1. The sol-gel derived organic-inorganic hybrid emulsion shows remarkable film-forming property when the mole ratio of MTES/TEOS reaches or exceeds 4:1. With the primer coating, the performance of superhydrophobic film achieve actual use standard. It reveals that this new procedure is an effective shortcut to obtain a superhydrophobic surface with potential applications.

  7. Ultrasensitive and selective detection of copper (II) and mercury (II) ions by dye-coded silver nanoparticle-based SERS probes.

    PubMed

    Li, Feng; Wang, Jing; Lai, Yuming; Wu, Chong; Sun, Shuqing; He, Yonghong; Ma, Hui

    2013-01-15

    A simple and distinctive method for the ultrasensitive detection of Cu(2+) and Hg(2+) based on surface-enhanced Raman scattering (SERS) using cysteine-functionalized silver nanoparticles (AgNPs) attached with Raman-labeling molecules was developed. The glycine residue in a silver nanoparticle-bound cysteine can selectively bind with Cu(2+) and Hg(2+) and form a stable inner complex. Silver nanoparticles co-functionalized with cysteine and 3,5-Dimethoxy-4-(6'-azobenzotriazolyl)phenol (AgNP conjugates) can be used to detect Cu(2+) and Hg(2+) based on aggregation-induced SERS of the Raman tags. The addition of SCN(-) to the analyte can successfully mask Hg(2+) and allow for the selective detection of Cu(2+). This SERS-based assay showed an unprecedented limit of detection (LOD) of 10pM for Cu(2+) and 1pM for Hg(2+); these LODs are a few orders of magnitude more sensitive than the typical colorimetric approach based on the aggregation of noble nanoparticles. The analysis of real water samples diluted with pure water was performed and verified this conclusion. We envisage that this SERS-based assay may provide a general and simple approach for the detection of other metal ions of interest, which can be adopted from their corresponding colorimetric assays that have already been developed with significantly improved sensitivity and thus have wide-range applications in many areas.

  8. Sensitive surface-enhanced Raman spectroscopy (SERS) detection of organochlorine pesticides by alkyl dithiol-functionalized metal nanoparticles-induced plasmonic hot spots.

    PubMed

    Kubackova, Jana; Fabriciova, Gabriela; Miskovsky, Pavol; Jancura, Daniel; Sanchez-Cortes, Santiago

    2015-01-06

    In this work, we report the detection of the organochlorine pesticides aldrin, dieldrin, lindane, and α-endosulfan by using surface-enhanced Raman spectroscopy (SERS) and optimization of the SERS-sensing substrate. In order to overcome the inherent problem of the low affinity of the above pesticides, we have developed a strategy consisting of functionalization of the metal surface with alkyl dithiols in order to achieve two different goals: (i) to induce the nanoparticle linkage and create interparticle junctions where sensitive hot spots needed for SERS enhancement are present, and (ii) to create a specific environment in the nanogaps between silver and gold nanoparticles, making them suitable for the assembly and SERS detection of the analyzed pesticides. Afterward, an optimization of the sensing substrate was performed by varying the experimental conditions: type of metal nanoparticles, molecular linker (aromatic versus aliphatic dithiols and the length of the intermediate chain), surface coverage, laser excitation wavelength. From the adsorption isotherms, it was possible to deduce the corresponding adsorption constant and the limit of detection. The present results confirm the high sensitivity of SERS for the detection of the organochlorine pesticides with a limit of detection reaching 10(-8) M, thus providing a solid basis for the construction of suitable nanosensors for the identification and quantitative analysis of this type of chemical.

  9. Engineering Gold Nanoparticles in Compass Shape with Broadly Tunable Plasmon Resonances and High-Performance SERS.

    PubMed

    Huang, Youju; Dai, Liwei; Song, Liping; Zhang, Lei; Rong, Yun; Zhang, Jiawei; Nie, Zhihong; Chen, Tao

    2016-10-04

    We present the uniform and high-yield synthesis of a novel gold nanostructure of compass shape composed of a Au sphere at the central and two gradually thinning conical tips at the opposed poles. The Au compass shapes were synthesized through a seed-mediated growth approach employing a binary mixture of cetyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL) as the structure-directing agents. Under the condition of single surfactant (CTAB), the spherical seeds tend to grow into larger spherical Au nanoparticles (NPs); while the spherical seeds favor the formation of Au compass shaped NPs using two mixed surfactants (CTAB/NaOL). The reaction kinetics clearly shows a growth mechanism of Au compass shaped NPs. Interestingly, due to their anisotropic structure, Au compass shaped NPs show two distinctive plasmonic resonances, similar to those from Au nanorods. Particularly, the longitudinal surface plasmon resonances of Au compass shaped NPs exhibit a broadly tunable range from 600 to 865 nm. In addition, the obtained Au compass shaped NPs can be self-assembled into a two-dimensional monolayer with closely packed and highly aligned NPs, which results in periodic arrays of overlapped Au tips, generating hot spots for high-performance surface-enhanced Raman scattering.

  10. Environmentally Friendly Preparation of Gold and Silver Nanoparticles for Sers Applications Using Biopolymer Pectin

    NASA Astrophysics Data System (ADS)

    Balachandran, Y. L.; Panarin, A. Y.; Khodasevich, I. A.; Terekhov, S. N.; Gutleb, A. C.; Girijaa, S.

    2015-01-01

    A facile, one-step, and environmentally friendly fabrication of anisotropic gold nanostructures and size-controlled spherical silver nanoparticles (NP) using biopolymer pectin is reported. The reduction of Au and Ag ions was carried out at room temperature using an increasing concentration of pectin, which acts as the single source of reducing and stabilizing agent. The as-formed NPs were studied by UV-vis, infrared Fourier transform and surface-enhanced Raman spectroscopies, as well as transmission electron microscopy and energy dispersive X-ray spectroscopy. A high yield of anisotropic gold nanostructures was observed at low concentrations of pectin, while its increase results in the formation of smaller sharp edged perfect triangles with a considerable number of quasi-spherically shaped gold NP. On the other hand, the size of spherical silver NP decreased as the biopolymer concentration in the solution increased. The surface-enhanced Raman scattering enhancement of different NPs was evaluated using a Cu-complex of cationic tetrakis(4-N-methylpyridyl)porphyrin as a probe molecule at 441.6 and 532 nm excitation. Great enhancement of Raman signal was obtained with a pectin-silver NP and for most of them their levels were higher than that for the routinely synthesized citrate silver NP.

  11. Hybrid Organic-Inorganic Perovskites on the Move.

    PubMed

    Egger, David A; Rappe, Andrew M; Kronik, Leeor

    2016-03-15

    Hybrid organic-inorganic perovskites (HOIPs) are crystals with the structural formula ABX3, where A, B, and X are organic and inorganic ions, respectively. While known for several decades, HOIPs have only in recent years emerged as extremely promising semiconducting materials for solar energy applications. In particular, power-conversion efficiencies of HOIP-based solar cells have improved at a record speed and, after only little more than 6 years of photovoltaics research, surpassed the 20% threshold, which is an outstanding result for a solution-processable material. It is thus of fundamental importance to reveal physical and chemical phenomena that contribute to, or limit, these impressive photovoltaic efficiencies. To understand charge-transport and light-absorption properties of semiconducting materials, one often invokes a lattice of ions displaced from their static positions only by harmonic vibrations. However, a preponderance of recent studies suggests that this picture is not sufficient for HOIPs, where a variety of structurally dynamic effects, beyond small harmonic vibrations, arises already at room temperature. In this Account, we focus on these effects. First, we review structure and bonding in HOIPs and relate them to the promising charge-transport and absorption properties of these materials, in terms of favorable electronic properties. We point out that HOIPs are much "softer" mechanically, compared to other efficient solar-cell materials, and that this can result in large ionic displacements at room temperature. We therefore focus next on dynamic structural effects in HOIPs, going beyond a static band-structure picture. Specifically, we discuss pertinent experimental and theoretical findings as to phase-transition behavior and molecular/octahedral rearrangements. We then discuss atomic diffusion phenomena in HOIPs, with an emphasis on the migration of intrinsic and extrinsic ionic species. From this combined perspective, HOIPs appear as highly

  12. Morphologies of mixed organic/inorganic/aqueous aerosol droplets.

    PubMed

    Song, Mijung; Marcolli, Claudia; Krieger, Ulrich K; Lienhard, Daniel M; Peter, Thomas

    2013-01-01

    Despite major progress in the understanding of properties of tropospheric aerosol particles, it remains challenging to understand their physical state and morphology. To obtain more detailed knowledge of the phases, phase transitions and morphologies of internally mixed organic/inorganic aerosol particles, we evaluated liquid-liquid phase separation (LLPS), deliquescence relative humidity (DRH) and efflorescence relative humidity (ERH) of 33 organic/ammonium sulfate (AS)/H2O systems from our own and literature data. The organic fraction consists of single compounds or mixtures with up to ten aliphatic and/or aromatic components with carboxylic acid, hydroxyl, carbonyl, ether, and ester functionalities, covering O : C ratios between 0.29 and 1.33. Thirteen out of these 33 systems did not show LLPS for any of the studied organic-to-inorganic mixing ratios, sixteen underwent LLPS showing core-shell morphology, and four showed both core-shell and partially engulfed configurations depending on the organic-to-inorganic ratio and RH. In all cases the organic fractions of the systems with partially engulfed configurations consisted of dicarboxylic acids. AS in mixed organic/AS/H2O particles deliquesced between 70 and 84% RH. AS effloresced below 58% RH or remained in a one-liquid-phase state. AS in droplets with LLPS always showed efflorescence with ERH between 30 and 50% RH, providing clear evidence that the presence of LLPS facilitates AS efflorescence. Spreading coefficients of the organic-rich phase on the AS-rich phase for systems containing polyethylene glycol 400 (PEG-400) and a mixture of dicarboxylic acids are in agreement with the optically observed morphologies of droplets deposited on the hydrophobic substrate. Analysis of high resolution elastic Mie resonance spectra allowed the detection of LLPS for single levitated droplets consisting of PEG-400/AS/ H2O, whereas LLPS was difficult to detect in (2-methylglutaric acid + 3-methylglutaric acid + 2

  13. Photophysical Properties of Novel Organic, Inorganic, and Hybrid Semiconductor Materials

    NASA Astrophysics Data System (ADS)

    Chang, Angela Yenchi

    For the past 200 years, novel materials have driven technological progress, and going forward these advanced materials will continue to deeply impact virtually all major industrial sectors. Therefore, it is vital to perform basic and applied research on novel materials in order to develop new technologies for the future. This dissertation describes the results of photophysical studies on three novel materials with electronic and optoelectronic applications, namely organic small molecules DTDCTB with C60 and C70, colloidal indium antimonide (InSb) nanocrystals, and an organic-inorganic hybrid perovskite with the composition CH3NH3PbI 3-xClx, using transient absorption (TA) and photoluminescence (PL) spectroscopy. In chapter 2, we characterize the timescale and efficiency of charge separation and recombination in thin film blends comprising DTDCTB, a narrow-band gap electron donor, and either C60 or C70 as an electron acceptor. TA and time-resolved PL studies show correlated, sub-picosecond charge separation times and multiple timescales of charge recombination. Our results indicate that some donors fail to charge separate in donor-acceptor mixed films, which suggests material manipulations may improve device efficiency. Chapter 3 describes electron-hole pair dynamics in strongly quantum-confined, colloidal InSb nanocrystal quantum dots. For all samples, TA shows a bleach feature that, for several picoseconds, dramatically red-shifts prior to reaching a time-independent position. We suggest this unusual red-shift relates transient population flow through two energetically comparable conduction band states. From pump-power-dependent measurements, we also determine biexciton lifetimes. In chapter 4, we examine carrier dynamics in polycrystalline methylammonium lead mixed halide perovskite (CH3NH3PbI3-xCl x) thin films as functions of temperature and photoexcitation wavelength. At room temperature, the long-lived TA signals stand in contrast to PL dynamics, where the

  14. Thin Film Solar Cells: Organic, Inorganic and Hybrid

    NASA Technical Reports Server (NTRS)

    Dankovich, John

    2004-01-01

    Thin film solar cells are an important developing resource for hundreds of applications including space travel. In addition to being more cost effective than traditional single crystal silicon cells, thin film multi-crystaline cells are plastic and light weight. The plasticity of the cells allows for whole solar panels to be rolled out from reams. Organic layers are being investigated in order to increase the efficiency of the cells to create an organic / inorganic hybrid cell. The main focus of the group is a thin film inorganic cell made with the absorber CuInS2. So far the group has been successful in creating the layer from a single-source precursor. They also use a unique method of film deposition called chemical vapor deposition for this. The general makeup of the cell is a molybdenum back contact with the CuInS2 layer, then CdS, ZnO and aluminum top contacts. While working cells have been produced, the efficiency so far has been low. Along with quantum dot fabrication the side project of this that is currently being studied is adding a polymer layer to increase efficiency. The polymer that we are using is P3OT (Poly(3-octylthiopene-2,5-diyll), retroregular). Before (and if) it is added to the cell, it must be understood in itself. To do this simple diodes are being constructed to begin to look at its behavior. The P3OT is spin coated onto indium tin oxide and silver or aluminum contacts are added. This method is being studied in order to find the optimal thickness of the layer as well as other important considerations that may later affect the composition of the finished solar cell. Because the sun is the most abundant renewable, energy source that we have, it is important to learn how to harness that energy and begin to move away from our other depleted non-renewable energy sources. While traditional silicon cells currently create electricity at relatively high efficiencies, they have drawbacks such as weight and rigidness that make them unattractive

  15. Thin Film Solar Cells: Organic, Inorganic and Hybrid

    NASA Technical Reports Server (NTRS)

    Dankovich, John

    2004-01-01

    Thin film solar cells are an important developing resource for hundreds of applications including space travel. In addition to being more cost effective than traditional single crystal silicon cells, thin film multi-crystaline cells are plastic and light weight. The plasticity of the cells allows for whole solar panels to be rolled out from reams. Organic layers are being investigated in order to increase the efficiency of the cells to create an organic / inorganic hybrid cell. The main focus of the group is a thin film inorganic cell made with the absorber CuInS2. So far the group has been successful in creating the layer from a single-source precursor. They also use a unique method of film deposition called chemical vapor deposition for this. The general makeup of the cell is a molybdenum back contact with the CuInS2 layer, then CdS, ZnO and aluminum top contacts. While working cells have been produced, the efficiency so far has been low. Along with quantum dot fabrication the side project of this that is currently being studied is adding a polymer layer to increase efficiency. The polymer that we are using is P3OT (Poly(3-octylthiopene-2,5-diyll), retroregular). Before (and if) it is added to the cell, it must be understood in itself. To do this simple diodes are being constructed to begin to look at its behavior. The P3OT is spin coated onto indium tin oxide and silver or aluminum contacts are added. This method is being studied in order to find the optimal thickness of the layer as well as other important considerations that may later affect the composition of the finished solar cell. Because the sun is the most abundant renewable, energy source that we have, it is important to learn how to harness that energy and begin to move away from our other depleted non-renewable energy sources. While traditional silicon cells currently create electricity at relatively high efficiencies, they have drawbacks such as weight and rigidness that make them unattractive

  16. Adhesion in flexible organic and hybrid organic/inorganic light emitting device and solar cells

    SciTech Connect

    Yu, D.; Kwabi, D.; Akogwu, O.; Du, J.; Oyewole, O. K.; Tong, T.; Anye, V. C.; Rwenyagila, E.; Asare, J.; Fashina, A.; Soboyejo, W. O.

    2014-08-21

    This paper presents the results of an experimental study of the adhesion between bi-material pairs that are relevant to organic light emitting devices, hybrid organic/inorganic light emitting devices, organic bulk heterojunction solar cells, and hybrid organic/inorganic solar cells on flexible substrates. Adhesion between the possible bi-material pairs is measured using force microscopy (AFM) techniques. These include: interfaces that are relevant to organic light emitting devices, hybrid organic/inorganic light emitting devices, bulk heterojunction solar cells, and hybrid combinations of titanium dioxide (TiO{sub 2}) and poly(3-hexylthiophene). The results of AFM measurements are incorporated into the Derjaguin-Muller-Toporov model for the determination of adhesion energies. The implications of the results are then discussed for the design of robust organic and hybrid organic/inorganic electronic devices.

  17. Effects of asperities and organic-inorganic interactions on the strength of nacre-mimetic composites.

    PubMed

    Lee, Yoonjoo; Kim, Bo-Yeon; Shin, Dong-Geun; Kim, Soo-Ryong; Kwon, Woo-Teck; Kim, Younghee

    2017-02-01

    Nacre is a natural organic-inorganic hybrid composite, whose hierarchical structure has a complex influence on its high strength. Many structural features have been discovered, which influence the mechanical properties of nacre, and the authors have a particular interest in the role of the asperities and organic-inorganic interactions. In this study, a composite was prepared which mimics the asperity structure using clay minerals. Organic-inorganic bonding was induced with silane treatment. Both factors increased the yield strength of the composites; however, different deformation behavior was exhibited. It was found that asperities improved the strength of the composite, and that composition influences the stiffness of the composite. The organic-inorganic interaction between the resin and the other components of the composite reduced the deformation of the composite and consequently improved strength. Copyright © 2016. Published by Elsevier B.V.

  18. Combining 3-D plasmonic gold nanorod arrays with colloidal nanoparticles as a versatile concept for reliable, sensitive, and selective molecular detection by SERS.

    PubMed

    Yilmaz, Mehmet; Senlik, Erhan; Biskin, Erhan; Yavuz, Mustafa Selman; Tamer, Ugur; Demirel, Gokhan

    2014-03-28

    The detection of molecules at an ultralow level by Surface-Enhanced Raman Spectroscopy (SERS) has recently attracted enormous interest for various applications especially in biological, medical, and environmental fields. Despite the significant progress, SERS systems are still facing challenges for practical applications related to their sensitivity, reliability, and selectivity. To overcome these limitations, in this study, we have proposed a simple yet facile concept by combining 3-D anisotropic gold nanorod arrays with colloidal gold nanoparticles having different shapes for highly reliable, selective, and sensitive detection of some hazardous chemical and biological warfare agents in trace amounts through SERS. The gold nanorod arrays were created on the BK7 glass slides or silicon wafer surfaces via the oblique angle deposition (OAD) technique without using any template material or lithography technique and their surface densities were adjusted by manipulating the deposition angle (α). It is found that gold nanorod arrays fabricated at α = 10° exhibited the highest SERS enhancement in the absence of colloidal gold nanoparticles. Synergetic enhancement was obviously observed in SERS signals when combining gold nanorod arrays with colloidal gold nanoparticles having different shapes (i.e., spherical, rod, and cage). Due to their ability to produce localized surface plasmons (LSPs) in transverse and longitudinal directions, utilization of colloidal gold nanorods as a synergetic agent led to an increase in the enhancement factor by about tenfold compared to plain gold nanorod arrays. Moreover, we have tested our approach to detect some chemical and biological toxins namely dipicolinic acid (DIP), methyl parathion (MP), and diethyl phosphoramidate (DP). For all toxins, Raman spectra with high signal-to-noise ratios and reproducibility were successfully obtained over a broad concentration range (5 ppm-10 ppb). Our results suggest that the slightly tangled and

  19. Organic/Inorganic Hybrid Perovskite FETs for Electrically Injected Laser Action

    DTIC Science & Technology

    2015-09-01

    NUMBER Organic/Inorganic Hybrid Perovskite FETs for Electrically- Injected Laser Action Sb. GRANT NUMBER ONR N00014-15-1-2943 Sc. PROGRAM ELEMENT...laser action aimed towards current injecting laser. For these studies we will use cw, transient and laser action techn iques on electrostatically gated...Office of Naval Research (ONR) Final grant report _QNR N00014-15-1-2943 Organic/Inorganic Hybrid Perovskite FETs for Electrically- Injected Laser

  20. A non-aqueous procedure to synthesize amino group bearing nanostructured organic-inorganic hybrid materials.

    PubMed

    Göring, M; Seifert, A; Schreiter, K; Müller, P; Spange, S

    2014-09-04

    Amino-functionalized organic-inorganic hybrid materials with a narrow distributed nanostructure of 2-4 nm in size were obtained by means of a template-free and non-aqueous procedure. Simultaneous twin polymerization of novel amino group containing twin monomers with 2,2'-spirobi[4H-1,3,2-benzodioxasiline] has been applied for this purpose. The amino groups of the organic-inorganic hybrid material are useful for post derivatization.

  1. New insights into organic-inorganic hybrid perovskite CH₃NH₃PbI₃ nanoparticles. An experimental and theoretical study of doping in Pb²⁺ sites with Sn²⁺, Sr²⁺, Cd²⁺ and Ca²⁺.

    PubMed

    Navas, Javier; Sánchez-Coronilla, Antonio; Gallardo, Juan Jesús; Hernández, Norge Cruz; Piñero, Jose Carlos; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; De los Santos, Desireé M; Aguilar, Teresa; Martín-Calleja, Joaquín

    2015-04-14

    This paper presents the synthesis of the organic-inorganic hybrid perovskite, CH3NH3PbI3, doped in the Pb(2+) position with Sn(2+), Sr(2+), Cd(2+) and Ca(2+). The incorporation of the dopants into the crystalline structure was analysed, observing how the characteristics of the dopant affected properties such as the crystalline phase, emission and optical properties. XRD showed how doping with Sn(2+), Sr(2+) and Cd(2+) did not modify the normal tetragonal phase. When doping with Ca(2+), the cubic phase was obtained. Moreover, DR-UV-Vis spectroscopy showed how the band gap decreased with the dopants, the values following the trend Sr(2+) < Cd(2+) < Ca(2+) < CH3NH3PbI3 ≈ Sn(2+). The biggest decrease was generated by Sr(2+), which reduced the CH3NH3PbI3 value by 4.5%. In turn, cathodoluminescence (CL) measurements confirmed the band gap obtained. Periodic-DFT calculations were performed to understand the experimental structures. The DOS analysis confirmed the experimental results obtained using UV-Vis spectroscopy, with the values calculated following the trend Sn(2+) ≈ Pb(2+) > Cd(2+) > Sr(2+) for the tetragonal structure and Pb(2+) > Ca(2+) for the cubic phase. The electron localization function (ELF) analysis showed similar electron localizations for undoped and Sn(2+)-doped tetragonal structures, which were different from those doped with Sr(2+) and Cd(2+). Furthermore, when Cd(2+) was incorporated, the Cd-I interaction was strengthened. For Ca(2+) doping, the Ca-I interaction had a greater ionic nature than Cd-I. Finally, an analysis based on the non-covalent interaction (NCI) index is presented to determine the weak-type interactions of the CH3NH3 groups with the dopant and I atoms. To our knowledge, this kind of analysis with these hybrid systems has not been performed previously.

  2. Shape control synthesis of spheroid and rod-like silver nanostructures in organic-inorganic sol-gel composite

    NASA Astrophysics Data System (ADS)

    Saraidarov, T.; Levchenko, V.; Popov, I.; Reisfeld, R.

    2009-07-01

    The synthesis of a variety of spheroid and rod-like silver nanoparticles in hybrid organic-inorganic sol-gel composite films was examined. The sol-gel matrix used in this work involves urethane terminated silica network which acts as a stabilizing and coupling agent and can complex with silver atoms through its secondary amine functionality and form stable colloid dispersions. The parameters determining the particles size and shape are the starting concentrations of silver ions, the coordination and reduction abilities of the solvent and the reaction kinetics and temperature. In this work the reduction process of silver ion was performed by DMF in sol-gel polyurethane precursor solution at two reaction temperatures: (a) 40 ∘C and (b) reflux at boiling temperature. The effects of concentration and temperature of solution on the morphology and uniformity of silver nanorods were investigated by UV-VIS spectroscopy, SEM and TEM. Spheroid nanoparticles size was as 10-12 nm. Electron diffraction shows that all nanoparticles have a silver face-centered cubic crystal lattice. The silver nanoparticles obtained in composite films exhibit a strong characteristic extinction peak, due to surface plasmon resonance occurring nearly 420-440 nm.

  3. Silver nanoparticles for SERS-based ultrasensitive chemical detection in aqueous solutions: Role of binding affinity and surface oxidation in the detection limit

    NASA Astrophysics Data System (ADS)

    Erol, Melek

    Surface-enhanced Raman spectroscopy (SERS) in the presence of noble metal nanostructures holds significant promise for sensing and molecular fingerprinting down to single molecule level. This dissertation explores the effect of binding affinity and surface oxidation of Ag nanoparticles on SERS detection sensitivity of SO42-, CN-, SCN-, ClO4- and nitro-aromatic compounds in water. Specifically positively charged Ag nanoparticles (Ag [+]) were synthesized by UV-assisted reduction of silver nitrate using branched polyethyleneimine (BPEI) and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) solutions. Both primary amino and amide groups on the surface of Ag [+] allowed strong binding affinity with anions, critical for sensitive SERS measurements. For substrates with immobilized Ag [+] (30 nanoparticles/mum2), SERS sensitivity increased in the order of SO42- < CN- < SCN- ≈ ClO4 -, with respective binding constants of 105, 3.3 x 105, and 107 (for both SCN- and ClO4-) M-1. Significantly, substrates with Ag [+] exhibited limit of detection values of 8.0 x 10-8 M (8 ppb) and 2.7 x 10-7 M (7 ppb) for ClO 4- and CN-, respectively. We revealed for the first time that oxidation of negatively charged Ag nanoparticles (Ag [-]) produced by a modified Lee and Meisel procedure drastically altered adsorption and orientation of nitro-aromatic molecules and increased their SERS detection limit. This observation can be attributed to the hinderance of Ag-to-aromatic ring charge transfer by the resultant oxide layer. SERS detection of p-nitrophenol at 1 ppt was achieved through inhibition of oxidation of Ag [-] in argon gas. Finally, to extend our work for potential biosensing applications, we showed that BPEI coatings of high molecular weight were unique in their ability to provide avidin-resistant surfaces at physiological conditions due to steric hindrance from the branched architecture of adsorbed polymer chains. BPEI coated surfaces were also effective for suppression of

  4. Highly reproducible SERS substrate based on polarization-free Ag nanoparticles decorated SiO2/Si core-shell nanowires array

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Ying; Huang, Jian-An; Yang, Bo; Zhang, Xue-Jin; Zhu, Yong-Yuan

    2015-05-01

    SiO2/Si core-shell nanowires array coated with gap-rich silver nanoparticles were demonstrated as a highly reproducible surface-enhanced Raman scattering (SERS) substrate. SERS detection of a relative standard deviation of 8% for 10-4 M R6G with a spot size of ˜2 μm and 900 spots over an area of 150 × 150 μm2 was reported. The high reproducibility is ascribed to the polarization-independent electrical field distribution among three-dimensional nanowire structure with an optimized thickness of SiO2 shell layer.

  5. Easily processable multimodal spectral converters based on metal oxide/organic-inorganic hybrid nanocomposites.

    PubMed

    Julián-López, Beatriz; Gonell, Francisco; Lima, Patricia P; Freitas, Vânia T; André, Paulo S; Carlos, Luis D; Ferreira, Rute A S

    2015-10-09

    This manuscript reports the synthesis and characterization of the first organic-inorganic hybrid material exhibiting efficient multimodal spectral converting properties. The nanocomposite, made of Er(3+), Yb(3+) codoped zirconia nanoparticles (NPs) entrapped in a di-ureasil d-U(600) hybrid matrix, is prepared by an easy two-step sol-gel synthesis leading to homogeneous and transparent materials that can be very easily processed as monolith or film. Extensive structural characterization reveals that zirconia nanocrystals of 10-20 nm in size are efficiently dispersed into the hybrid matrix and that the local structure of the di-ureasil is not affected by the presence of the NPs. A significant enhancement in the refractive index of the di-ureasil matrix with the incorporation of the ZrO2 nanocrystals is observed. The optical study demonstrates that luminescent properties of both constituents are perfectly preserved in the final hybrid. Thus, the material displays a white-light photoluminescence from the di-ureasil component upon excitation at UV/visible radiation and also intense green and red emissions from the Er(3+)- and Yb(3+)-doped NPs after NIR excitation. The dynamics of the optical processes were also studied as a function of the lanthanide content and the thickness of the films. Our results indicate that these luminescent hybrids represent a low-cost, environmentally friendly, size-controlled, easily processed and chemically stable alternative material to be used in light harvesting devices such as luminescent solar concentrators, optical fibres and sensors. Furthermore, this synthetic approach can be extended to a wide variety of luminescent NPs entrapped in hybrid matrices, thus leading to multifunctional and versatile materials for efficient tuneable nonlinear optical nanodevices.

  6. Electrospun Superhydrophobic Organic/Inorganic Composite Nanofibrous Membranes for Membrane Distillation.

    PubMed

    Li, Xiong; Yu, Xufeng; Cheng, Cheng; Deng, Li; Wang, Min; Wang, Xuefen

    2015-10-07

    Electrospun superhydrophobic organic/inorganic composite nanofibrous membranes exhibiting excellent direct contact membrane distillation (DCMD) performance were fabricated by a facile route combining the hydrophobization of silica nanoparticles (SiO2 NPs) and colloid electrospinning of the hydrophobic silica/poly(vinylidene fluoride) (PVDF) matrix. Benefiting from the utilization of SiO2 NPs with three different particle sizes, the electrospun nanofibrous membranes (ENMs) were endowed with three different delicate nanofiber morphologies and fiber diameter distribution, high porosity, and superhydrophobic property, which resulted in excellent waterproofing and breathability. Significantly, structural attributes analyses have indicated the major contributing role of fiber diameter distribution on determining the augment of permeate vapor flux through regulating mean flow pore size (MFP). Meanwhile, the extremely high liquid entry pressure of water (LEPw, 2.40 ± 0.10 bar), robust nanofiber morphology of PVDF immobilized SiO2 NPs, remarkable mechanical properties, thermal stability, and corrosion resistance endowed the as-prepared membranes with prominent desalination capability and stability for long-term MD process. The resultant choreographed PVDF/silica ENMs with optimized MFP presented an outstanding permeate vapor flux of 41.1 kg/(m(2)·h) and stable low permeate conductivity (∼2.45 μs/cm) (3.5 wt % NaCl salt feed; ΔT = 40 °C) over a DCMD test period of 24 h without membrane pores wetting detected. This result was better than those of typical commercial PVDF membranes and PVDF and modified PVDF ENMs reported so far, suggesting them as promising alternatives for MD applications.

  7. Organic-inorganic hybrid nanostructures for solar cell applications

    NASA Astrophysics Data System (ADS)

    AbdulAlmohsin, Samir M.

    The enticing electro-optical properties of nanostructured materials such as carbon nanotubes, graphene, CdS nanocrystals and ZnO nanowrie bring new vigor into the innovation of photovoltaics. The main purpose of this dissertation is to develop novel nano-structured materials for low cost solar cell applications. Fabrication, characterization, and solar cell application of organic-inorganic hybrid structures are the main focus of this research. Polyaniline (PANI)/multi-walled carbon nanotube (MWNT) composite films were synthesized by an electrochemical polymerization of aniline with airbrushed MWNTs on ITO substrates. It was found that the incorporation of MWNTs in PANI effectively increase the film conductivity with a percolation threshold of 5% of nanotubes in the composite. The solar cell performance strongly depends on the conductivity of the composite films, which can be tuned by adjusting nanotube concentration. A higher conductivity resulted in a better cell performance, resulting from an efficient charge collection. This study indicates that PANI/MWNT composite films with optimized conductivity are potentially useful for low-cost hybrid solar cell applications. CdS nanocrystal-sensitized solar cells (NCSSCs) were investigated by using polyaniline (PANI) as a replacement for conventional platinum counter electrode. The growth time of the nanocrystals significantly affects the solar cell performance. At an optimum growth, the NCSSCs exhibit 0.83% of the conversion efficiency in comparison to 0.13% for the identical cells without CdS nanocrystals. Electrochemical impedance spectroscopy showed that the charge transfer in the solar cells with CdS nanocrystals was improved. The enhanced overall energy conversion efficiency by nanocrystals is attributed to improved light absorption and suppressed recombination rate of interfacial charges at the injection, resulting in significantly improved charge transfer and electron lifetime. In addition, the PANI electrodes

  8. Organic/Inorganic Hybrid Nanocomposite Infrared Photodetection by Intraband Absorption

    NASA Astrophysics Data System (ADS)

    Lantz, Kevin Richard

    The ability to detect infrared radiation is vital for a host of applications that include optical communication, medical diagnosis, thermal imaging, atmospheric monitoring, and space science. The need to actively cool infrared photon detectors increases their operation cost and weight, and the focus of much recent research has been to limit the dark current and create room-temperature infrared photodetectors appropriate for mid-to-long-wave infrared detection. Quantum dot infrared photodetectors (QDIPs) provide electron quantum confinement in three dimensions and have been shown to demonstrate high temperature operation (T>150 K) due to lower dark currents. However, these inorganic devices have not achieved sensitivity comparable to state-of-the-art photon detectors, due in large part to the inability to control the uniformity (size and shape) of QDs during strained-layer epitaxy. The purpose of this dissertation research was to investigate the feasibility of room-temperature infrared photodetection that could overcome the shortfalls of QDIPs by using chemically synthesized inorganic colloidal quantum dots (CQDs). CQDs are coated with organic molecules known as surface ligands that prevent the agglomeration of dots while in solution. When CQDs are suspended in a semiconducting organic polymer, these materials are known as organic/inorganic hybrid nanocomposites. The novel approach investigated in this work was to use intraband transitions in the conduction band of the polymer-embedded CQD for room-temperature photodetection in the mid-wave, and possibly long-wave, infrared ranges. Hybrid nanocomposite materials promise room-temperature operation due to: (i) large bandgaps of the inorganic CQDs and the semiconducting polymer that reduce thermionic emission; and (ii) low dark current due to the three-dimensional electron confinement in the CQD and low carrier mobility in the semiconducting polymer. The primary material system investigated in this research was Cd

  9. Efficient Enrichment and Self-Assembly of Hybrid Nanoparticles into Removable and Magnetic SERS Substrates for Sensitive Detection of Environmental Pollutants.

    PubMed

    Tang, Siying; Li, Yong; Huang, Hao; Li, Penghui; Guo, Zhinan; Luo, Qian; Wang, Zhe; Chu, Paul K; Li, Jia; Yu, Xue-Feng

    2017-03-01

    A structure consisting of a low surface energy substrate and low surface tension liquid is designed and prepared by taking advantage of perfluorinated fluid infusion into the porous Teflon membrane. This slippery platform allows efficient enrichment and self-assembly of hybrid nanoparticles and the assembled structure can be detached from the membrane. A macroscale superlattice array of Au nanorods doped with magnetic Fe3O4 nanoparticles is obtained by suppressing the outward capillary flow and coffee-ring effect during evaporative self-assembly. In SERS (surface enhanced Raman scattering) detection of environmental pollutants including thiram, diquat and polycyclic aromatic hydrocarbons, the removable plasmonic superlattice array with magnetic properties enables rapid separation of analytes from the solution resulting in excellent sensitivity and detection limits down to the nanomolar level. The self-assembly strategy shows great potential in the fabrication of removable 3D plasmonic superlattice arrays for SERS detections.

  10. Surface-enhanced Raman scattering (SERS) imaging of alkyne-tagged small molecule drug in live cells with endocytosed gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Ando, Jun; Sekiya, Takumasa; Ka, Den; Yamakoshi, Hiroyuki; Dodo, Kosuke; Sodeoka, Mikiko; Kawata, Satoshi; Fujita, Katsumasa

    2017-02-01

    We propose the combination of alkyne-tag and surface-enhanced Raman scattering (SERS) spectroscopy to perform highly-sensitive and selective drug imaging in live cells. Gold nanoparticles are introduced in lysosomes through endocytosis as SERS agents, and the alkyne-tagged drugs are subsequently administered in cells. Raman microscopic observation reveals the arrival of drug in lysosome through enhanced Raman signal of alkyne. Since the peak of alkyne appears in Raman-silent region of biomolecules, selective detection of drugs is possible without background signal of endogenous molecules. From endocytosed gold nanoparticles in living HeLa cells, we observed distinct Raman signal from alkyne-tagged inhibitor of lysosomal enzyme.

  11. Toxicology of organic-inorganic hybrid molecules: bio-organometallics and its toxicology.

    PubMed

    Fujie, Tomoya; Hara, Takato; Kaji, Toshiyuki

    2016-01-01

    Bio-organometallics is a research strategy of biology that uses organic-inorganic hybrid molecules. The molecules are expected to exhibit useful bioactivities based on the unique structure formed by interaction between the organic structure and intramolecular metal(s). However, studies on both biology and toxicology of organic-inorganic hybrid molecules have been incompletely performed. There can be two types of toxicological studies of bio-organometallics; one is evaluation of organic-inorganic hybrid molecules and the other is analysis of biological systems from the viewpoint of toxicology using organic-inorganic hybrid molecules. Our recent studies indicate that cytotoxicity of hybrid molecules containing a metal that is nontoxic in inorganic forms can be more toxic than that of hybrid molecules containing a metal that is toxic in inorganic forms when the structure of the ligand is the same. Additionally, it was revealed that organic-inorganic hybrid molecules are useful for analysis of biological systems important for understanding the toxicity of chemical compounds including heavy metals.

  12. SERS characterization of neuropeptide Y and its C-terminal fragments deposited onto colloidal gold nanoparticle surface.

    PubMed

    Domin, Helena; Piergies, Natalia; Święch, Dominika; Pięta, Ewa; Proniewicz, Edyta

    2017-01-01

    It has been suggested that the family of neuropeptide Y (NPY) peptides is a promising target for the neuroprotective therapy; therefore, knowledge of the structure of these biologically active compounds and their behavior at solid/liquid interface is important in order to design new analogues. Because there is still a lack of detailed information on the behavior of NPY and its mutated analogues at the solid/liquid interfaces, in this work surface-enhanced Raman spectroscopy (SERS) analysis was used to investigate NPY and its native NPY(3-36), NPY(13-36), and NPY(22-36) and mutated acetyl-(Leu(28,31))-NPY(24-36)C-terminal fragments, acting on Y2 receptors (Y2R), in order to determine their possible metal surface/molecule interactions. In these studies, colloidal gold nanoparticle surface served as a solid surface, whereas an aqueous solution was used as a liquid medium. The observed differences in the band intensities, wavenumbers, and widths allowed us to draw conclusions on an adsorption mode of NPY and on changes in this mode upon the shortening of the peptide chain and increase in solution pH (from pH 3 to pH 11). Briefly, three different species of Tyr were identified onto the colloidal gold surface depending upon the length of the peptide chain and solution pH. Tyrosine (TyrOH) is present in a basic medium. Tyrosinate (TyrO(-)) is present in an acidic solution, whereas phenoxyl radical (Tyr(*)) appears at neutral pH for peptides having relatively short peptide chain (acetyl-(Leu(28,31))-NPY(24-36)). The elongation of the peptide chain partially (NPY(13-36) and NPY(22-36)) or completely (NPY(3-36) and NPY) protects the Tyr residue against conversion to the radical form. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. A SERS-active sensor based on heterogeneous gold nanostar core-silver nanoparticle satellite assemblies for ultrasensitive detection of aflatoxinB1

    NASA Astrophysics Data System (ADS)

    Li, Aike; Tang, Lijuan; Song, Dan; Song, Shanshan; Ma, Wei; Xu, Liguang; Kuang, Hua; Wu, Xiaoling; Liu, Liqiang; Chen, Xin; Xu, Chuanlai

    2016-01-01

    A surface-enhanced Raman scattering (SERS) sensor based on gold nanostar (Au NS) core-silver nanoparticle (Ag NP) satellites was fabricated for the first time to detect aflatoxinB1 (AFB1). We constructed the SERS sensor using AFB1 aptamer (DNA1)-modified Ag satellites and a complementary sequence (DNA2)-modified Au NS core. The Raman label (ATP) was modified on the surface of Ag satellites. The SERS signal was enhanced when the satellite NP was attached to the Au core NS. The AFB1 aptamer on the surface of Ag satellites would bind to the targets when AFB1 was present in the system, Ag satellites were then removed and the SERS signal decreased. This SERS sensor showed superior specificity for AFB1 and the linear detection range was from 1 to 1000 pg mL-1 with the limit of detection (LOD) of 0.48 pg mL-1. The excellent recovery experiment using peanut milk demonstrated that the sensor could be applied in food and environmental detection.A surface-enhanced Raman scattering (SERS) sensor based on gold nanostar (Au NS) core-silver nanoparticle (Ag NP) satellites was fabricated for the first time to detect aflatoxinB1 (AFB1). We constructed the SERS sensor using AFB1 aptamer (DNA1)-modified Ag satellites and a complementary sequence (DNA2)-modified Au NS core. The Raman label (ATP) was modified on the surface of Ag satellites. The SERS signal was enhanced when the satellite NP was attached to the Au core NS. The AFB1 aptamer on the surface of Ag satellites would bind to the targets when AFB1 was present in the system, Ag satellites were then removed and the SERS signal decreased. This SERS sensor showed superior specificity for AFB1 and the linear detection range was from 1 to 1000 pg mL-1 with the limit of detection (LOD) of 0.48 pg mL-1. The excellent recovery experiment using peanut milk demonstrated that the sensor could be applied in food and environmental detection. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08372a

  14. Highly narrow nanogap-containing Au@Au core-shell SERS nanoparticles: size-dependent Raman enhancement and applications in cancer cell imaging

    NASA Astrophysics Data System (ADS)

    Hu, Chongya; Shen, Jianlei; Yan, Juan; Zhong, Jian; Qin, Weiwei; Liu, Rui; Aldalbahi, Ali; Zuo, Xiaolei; Song, Shiping; Fan, Chunhai; He, Dannong

    2016-01-01

    Cellular imaging technologies employing metallic surface-enhanced Raman scattering (SERS) tags have gained much interest toward clinical diagnostics, but they are still suffering from poor controlled distribution of hot spots and reproducibility of SERS signals. Here, we report the fabrication and characterization of high narrow nanogap-containing Au@Au core-shell SERS nanoparticles (GCNPs) for the identification and imaging of proteins overexpressed on the surface of cancer cells. First, plasmonic nanostructures are made of gold nanoparticles (~15 nm) coated with gold shells, between which a highly narrow and uniform nanogap (~1.1 nm) is formed owing to polyA anchored on the Au cores. The well controlled distribution of Raman reporter molecules, such as 4,4'-dipyridyl (44DP) and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), are readily encoded in the nanogap and can generate strong, reproducible SERS signals. In addition, we have investigated the size-dependent SERS activity of GCNPs and found that with the same laser wavelength, the Raman enhancement discriminated between particle sizes. The maximum Raman enhancement was achieved at a certain threshold of particle size (~76 nm). High narrow nanogap-containing Au@Au core-shell SERS tags (GCTs) were prepared via the functionalization of hyaluronic acid (HA) on GCNPs, which recognized the CD44 receptor, a tumor-associated surface biomarker. And it was shown that GCTs have a good targeting ability to tumour cells and promising prospects for multiplex biomarker detection.Cellular imaging technologies employing metallic surface-enhanced Raman scattering (SERS) tags have gained much interest toward clinical diagnostics, but they are still suffering from poor controlled distribution of hot spots and reproducibility of SERS signals. Here, we report the fabrication and characterization of high narrow nanogap-containing Au@Au core-shell SERS nanoparticles (GCNPs) for the identification and imaging of proteins overexpressed on

  15. Charge transfer at organic-inorganic interfaces—Indoline layers on semiconductor substrates

    NASA Astrophysics Data System (ADS)

    Meyenburg, I.; Falgenhauer, J.; Rosemann, N. W.; Chatterjee, S.; Schlettwein, D.; Heimbrodt, W.

    2016-12-01

    We studied the electron transfer from excitons in adsorbed indoline dye layers across the organic-inorganic interface. The hybrids consist of indoline derivatives on the one hand and different inorganic substrates (TiO2, ZnO, SiO2(0001), fused silica) on the other. We reveal the electron transfer times from excitons in dye layers to the organic-inorganic interface by analyzing the photoluminescence transients of the dye layers after femtosecond excitation and applying kinetic model calculations. A correlation between the transfer times and four parameters have been found: (i) the number of anchoring groups, (ii) the distance between the dye and the organic-inorganic interface, which was varied by the alkyl-chain lengths between the carboxylate anchoring group and the dye, (iii) the thickness of the adsorbed dye layer, and (iv) the level alignment between the excited dye ( π* -level) and the conduction band minimum of the inorganic semiconductor.

  16. Synthesis of organic-inorganic hybrid sols using trifunctional organoalkoxysilanes for dispersion agents.

    PubMed

    Park, Hoyyul; Kang, Dongjun; Ahn, Myeongsang; Lee, Hyeonhwa

    2012-02-01

    We investigated the properties of synthetically produced organic-inorganic hybrid coatings by a sol-gel process. The properties of organic-inorganic hybrid materials arise from the synergism between the properties of the individual components. One of the typical way to synthesize the organic-inorganic hybrid materials is to use silica and silanes. A colloidal silica sol was used as an inorganic material. Methyltrimethoxysilane and phenyltrimethoxysilane were used as the trifunctional organoalkoxysilanes. Hybrid sols of colloidal silica and silanes were synthesized as a function of reaction time and methyltrimethoxysilane/phenyltrimethoxysilane ratio by a sol-gel process. Physical properties of sol solutions such as stability, viscosity, and transmittance were investigated. The surface roughness and surface free energy of the coatings were also measured.

  17. Ultrahigh and Broad Spectral Photodetectivity of an Organic-Inorganic Hybrid Phototransistor for Flexible Electronics.

    PubMed

    Rim, You Seung; Yang, Yang Micheal; Bae, Sang-Hoon; Chen, Huajun; Li, Chao; Goorsky, Mark S; Yang, Yang

    2015-11-18

    The creation of new organic-inorganic phototransistors with high and broad spectral photosensitivity is reported. The extended charge transport and photoconductivity between the layers in the bilayer structure results in a notable detectivity of over 10(12) Jones and a linear dynamic range of over 100 dB at a broad spectral bandwidth across the UV-NIR range. Furthermore, the considerably reduced persistent photocurrent effect of In-Ga-Zn-O (IGZO)-based hybrid phototransistors is first demonstrated via an organic-inorganic bilayer approach.

  18. Three dimensional design of large-scale TiO(2) nanorods scaffold decorated by silver nanoparticles as SERS sensor for ultrasensitive malachite green detection.

    PubMed

    Tan, En-Zhong; Yin, Peng-Gang; You, Ting-Ting; Wang, Hua; Guo, Lin

    2012-07-25

    We have designed a large-scale three-dimensional (3D) hybrid nanostructure as surface-enhanced Raman scattering (SERS) sensor by decorating silver nanoparticles on TiO2 nanorods scaffold (Ag/TiO2). Taking p-mercaptobenzoic acid (PMBA) as the probe molecule, the SERS signals collected by point-to-point and time mapping modes show that the relative standard deviation (RSD) in the intensity of the main Raman vibration modes (1079, 1586 cm(-1)) is less than 10%, demonstrating good spatial uniformity and time stability. This hybrid substrate also exhibits excellent SERS enhancement effect due to the formation of high-density hot spots among the AgNPs, which was proved by finite-difference time-domain (FDTD) simulations. The application of the new nanostructures as SERS sensors was demonstrated with the detection of malachite green (MG). The quantification of MG can be accomplished with the detection limit of 1 × 10(-12) M based on the Raman intensity. The results show that the Ag/TiO2 nanostructure can be a promising candidate for SERS sensor.

  19. DEVELOPMENT OF SERS SPECTROSCOPY FOR ROUTINE AND RAPID IDENTIFICATION OF ESCHERICHIA COLI AND LISTERIA MONOCYTOGENES ON SILVER COLLOIDAL NANOPARTICLES

    USDA-ARS?s Scientific Manuscript database

    SERS spectra were collected to explore its potential for rapid and routine identification of E. coli and L. monocytogenes cultures. Ratios of SERS peaks from K3PO4 were used to evaluate the reproducibility, stability, and binding effectiveness of citrate-reduced silver colloids over batch and storag...

  20. Sulfur-Containing Organic-Inorganic Hybrid Gel Compositions and Aerogels

    NASA Technical Reports Server (NTRS)

    Evans, Owen R. (Inventor); Dong, Wenting (Inventor); Deshpande, Kiranmayi (Inventor)

    2015-01-01

    Methods and materials are described for preparing organic-inorganic hybrid gel compositions where a sulfur-containing cross-linking agent covalently links the organic and inorganic components. The gel compositions are further dried to provide porous gel compositions and aerogels. The mechanical and thermal properties of the dried gel compositions are also disclosed.

  1. Design and properties of functional hybrid organic-inorganic membranes for fuel cells.

    PubMed

    Laberty-Robert, C; Vallé, K; Pereira, F; Sanchez, C

    2011-02-01

    This critical review presents a discussion on the major advances in the field of organic-inorganic hybrid membranes for fuel cells application. The hybrid organic-inorganic approach, when the organic part is not conductive, reproduces to some extent the behavior of Nafion where discrete hydrophilic and hydrophilic domains are homogeneously distributed. A large variety of proton conducting or non conducting polymers can be combined with various functionalized, inorganic mesostructured particles or an inorganic network in order to achieve high proton conductivity, and good mechanical and chemical properties. The tuning of the interface between these two components and the control over chemical and processing conditions are the key parameters in fabricating these hybrid organic-inorganic membranes with a high degree of reproducibility. This dynamic coupling between chemistry and processing requires the extensive use and development of complementary ex situ measurements with in situ characterization techniques, following in real time the molecular precursor solutions to the formation of the final hybrid organic-inorganic membranes. These membranes combine the intrinsic physical and chemical properties of both the inorganic and organic components. The development of the sol-gel chemistry allows a fine tuning of the inorganic network, which exhibits acid-based functionalized pores (-SO(3)H, -PO(3)H(2), -COOH), tunable pore size and connectivity, high surface area and accessibility. As such, these hybrid membranes containing inorganic materials are a promising family for controlling conductivity, mechanical and chemical properties (349 references).

  2. Auto-organisation of hybrid organic-inorganic materials prepared by sol-gel process.

    PubMed

    Boury, Bruno; Corriu, Robert J P

    2002-04-21

    Silica-based hybrid organic-inorganic materials prepared by sol-gel chemistry exhibit chemical and physical properties revealing their anisotropic organisation. Besides the opportunities that this phenomenon opens for the preparation of new materials, it also provides arguments to the chemist looking for a better comprehension and control of the organisation of solids.

  3. Fabrication and characterization of materials and structures for hybrid organic-inorganic photonics

    NASA Astrophysics Data System (ADS)

    Haško, Daniel; Chovan, Jozef; Uherek, František

    2017-03-01

    Hybrid organic-inorganic integrated photonics integrate the organic material, as a part of active layer, with inorganic structure, and it is the organic component that extends the functionalities as compared to inorganic photonics. This paper presents the results of fabrication and characterization of inorganic and organic layers, as well as of hybrid organic-inorganic structures. Inorganic oxide and nitride materials and structures were grown using plasma enhanced chemical vapor deposition. As a substrate for tested organic layers and for preparation of multilayer structures, commercially available SiO2 created by thermal oxidation on Si was used. The hybrid organic-inorganic structures were prepared by spin coating of organic materials on SiO2/Si inorganic structures. As the basic photonics devices, the testing strip inorganic and organic waveguides were fabricated using reactive ion etching. The shape of fabricated testing waveguides was trapezoidal and etched structures were able to guide the radiation. The presented technology enabled to prepare hybrid organic-inorganic structures of comparable dimensions and shape. The fabricated waveguides dimensions and shape will be used for optimisation and design of new lithographic mask to prepare photonic components with required characteristics.

  4. Reactivity II: A Second Foundation-Level Course in Integrated Organic, Inorganic, and Biochemistry

    ERIC Educational Resources Information Center

    Schaller, Chris P.; Graham, Kate J.; McIntee, Edward J.; Jones, T. Nicholas; Johnson, Brian J.

    2016-01-01

    A foundation-level course is described that integrates material related to reactivity in organic, inorganic, and biochemistry. Designed for second-year students, the course serves majors in chemistry, biochemistry, and biology, as well as prehealth-professions students. Building on an earlier course that developed concepts of nucleophiles and…

  5. Reactivity III: An Advanced Course in Integrated Organic, Inorganic, and Biochemistry

    ERIC Educational Resources Information Center

    Schaller, Chris P.; Graham, Kate J.; Jakubowski, Henry V.

    2017-01-01

    Reactivity III is a new course that presents chemical reactions from the domains of organic, inorganic, and biochemistry that are not readily categorized by electrophile-nucleophile interactions. Many of these reactions involve the transfer of a single electron, in either an intermolecular fashion in the case of oxidation/reduction reactions or an…

  6. Reactivity II: A Second Foundation-Level Course in Integrated Organic, Inorganic, and Biochemistry

    ERIC Educational Resources Information Center

    Schaller, Chris P.; Graham, Kate J.; McIntee, Edward J.; Jones, T. Nicholas; Johnson, Brian J.

    2016-01-01

    A foundation-level course is described that integrates material related to reactivity in organic, inorganic, and biochemistry. Designed for second-year students, the course serves majors in chemistry, biochemistry, and biology, as well as prehealth-professions students. Building on an earlier course that developed concepts of nucleophiles and…

  7. Hybrid organic-inorganic network coatings for protecting metal substrates from abrasion and corrosion

    SciTech Connect

    Jordens, K.; Wilkes, G.

    1996-12-31

    Ceramers or Ormocers are hybrid organic-inorganic materials first created a decade ago, and are the subject of a recent review article. Recent research from the authors laboratory in this area of materials science has focused on synthesizing protective coatings for (soft) polymeric substrates, i.e. polycarbonate. The authors have now extended the application of such coatings to metallic substrates.

  8. Preparation and characterization of cellulose acetate organic/inorganic hybrid films

    Treesearch

    Saeed S. Shojaie; Timothy G. Rials; Stephen S. Kelley

    1995-01-01

    A series of organic/inorganic hybrid (OIH) films were prepared using cellulose acetate (CA) as the organic component and tetraethyl orthosilicate (TEOS) as the inorganic component. The chemical, morphological, and mechanical properties of these films were evaluated with a variety of analytical techniques. The results of these evaluations showed that crosslinked CA OIH...

  9. Organic-inorganic hybrid mesoporous silicas: functionalization, pore size, and morphology control.

    PubMed

    Park, Sung Soo; Ha, Chang-Sik

    2006-01-01

    Topological design of mesoporous silica materials, pore architecture, pore size, and morphology are currently major issues in areas such as catalytic conversion of bulky molecules, adsorption, host-guest chemistry, etc. In this sense, we discuss the pore size-controlled mesostructure, framework functionalization, and morphology control of organic-inorganic hybrid mesoporous silicas by which we can improve the applicability of mesoporous materials. First, we explain that the sizes of hexagonal- and cubic-type pores in organic-inorganic hybrid mesoporous silicas are well controlled from 24.3 to 98.0 A by the direct micelle-control method using an organosilica precursor and surfactants with different alkyl chain lengths or triblock copolymers as templates and swelling agents incorporated in the formed micelles. Second, we describe that organic-inorganic hybrid mesoporous materials with various functional groups form various external morphologies such as rod, cauliflower, film, rope, spheroid, monolith, and fiber shapes. Third, we discuss that transition metals (Ti and Ru) and rare-earth ions (Eu(3+) and Tb(3+)) are used to modify organic-inorganic hybrid mesoporous silica materials. Such hybrid mesoporous silica materials are expected to be applied as excellent catalysts for organic reactions, photocatalysis, optical devices, etc. c) 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

  10. Photochemical Decoration of Silver Nanocrystals on Magnetic MnFe2O4 Nanoparticles and Their Applications in Antibacterial Agents and SERS-Based Detection

    NASA Astrophysics Data System (ADS)

    Huy, Le Thanh; Tam, Le Thi; Van Son, Tran; Cuong, Nguyen Duy; Nam, Man Hoai; Vinh, Le Khanh; Huy, Tran Quang; Ngo, Duc-The; Phan, Vu Ngoc; Le, Anh-Tuan

    2017-01-01

    In this study, multifunctional nanocomposites consisting of silver nanoparticles and manganese ferrite nanoparticles (Ag-MnFe2O4) were successfully synthesized using a two-step chemical process. The formation of Ag-MnFe2O4 nanocomposites were analyzed by transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy measurements. Noticeable antibacterial activity of the Ag-MnFe2O4 nanocomposites was demonstrated against two Gram-negative bacteria, Salmonella enteritidis and Klebsiella pneumoniae. A direct-drop diffusion method can be an effective way to investigate the antibacterial effects of nanocomposite samples. Interestingly, we also demonstrated the use of Ag-MnFe2O4 nanocomposites as a surface-enhanced Raman scattering (SERS) platform to detect and quantify trace amounts of organic dye in water solutions. The combination of Ag and MnFe2O4 nanoparticles opens opportunities for creating advantages such as targeted bactericidal delivery, recyclable capability, and sensitive SERS-based detection for advanced biomedicine and environmental monitoring applications.

  11. Photochemical Decoration of Silver Nanocrystals on Magnetic MnFe2O4 Nanoparticles and Their Applications in Antibacterial Agents and SERS-Based Detection

    NASA Astrophysics Data System (ADS)

    Huy, Le Thanh; Tam, Le Thi; Van Son, Tran; Cuong, Nguyen Duy; Nam, Man Hoai; Vinh, Le Khanh; Huy, Tran Quang; Ngo, Duc-The; Phan, Vu Ngoc; Le, Anh-Tuan

    2017-06-01

    In this study, multifunctional nanocomposites consisting of silver nanoparticles and manganese ferrite nanoparticles (Ag-MnFe2O4) were successfully synthesized using a two-step chemical process. The formation of Ag-MnFe2O4 nanocomposites were analyzed by transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy measurements. Noticeable antibacterial activity of the Ag-MnFe2O4 nanocomposites was demonstrated against two Gram-negative bacteria, Salmonella enteritidis and Klebsiella pneumoniae. A direct-drop diffusion method can be an effective way to investigate the antibacterial effects of nanocomposite samples. Interestingly, we also demonstrated the use of Ag-MnFe2O4 nanocomposites as a surface-enhanced Raman scattering (SERS) platform to detect and quantify trace amounts of organic dye in water solutions. The combination of Ag and MnFe2O4 nanoparticles opens opportunities for creating advantages such as targeted bactericidal delivery, recyclable capability, and sensitive SERS-based detection for advanced biomedicine and environmental monitoring applications.

  12. Fabrication of silver nanoparticles embedded into polyvinyl alcohol (Ag/PVA) composite nanofibrous films through electrospinning for antibacterial and surface-enhanced Raman scattering (SERS) activities.

    PubMed

    Zhang, Zhijie; Wu, Yunping; Wang, Zhihua; Zou, Xueyan; Zhao, Yanbao; Sun, Lei

    2016-12-01

    Silver nanoparticle-embedded polyvinyl alcohol (PVA) nanofibers were prepared through electrospinning technique, using as antimicrobial agents and surface-enhanced Raman scattering (SERS) substrates. Ag nanoparticles (NPs) were synthesized in liquid phase, followed by evenly dispersing in PVA solution. After electrospinning of the mixed solution at room temperature, the PVA embedded with Ag NPs (Ag/PVA) composite nanofibers were obtained. The morphologies and structures of the as-synthesized Ag nanoparticles and Ag/PVA fibers were characterized by the techniques of transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Ag NPs have an average diameter of 13.8nm, were found to be uniformly dispersed in PVA nanofibers. The Ag/PVA nanofibers provided robust antibacterial activities against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) microorganisms. It's also found that Ag/PVA nanofibers make a significant contribution to the high sensitivity of SERS to 4-mercaptophenol (4-MPh) molecules.

  13. SERS spectroscopy of kaempferol and galangin under the interaction of human serum albumin with adsorbed silver nanoparticles.

    PubMed

    Zhang, Wei; Bai, Xueyuan; Wang, Yingping; Zhao, Bing; Zhao, Daqing; Zhao, Yu

    2012-06-15

    Raman and surface-enhanced Raman scattering (SERS) spectroscopy were employed to probe the interaction of the flavonol drugs, kaempferol and galangin, with human serum albumin (HSA). SERS spectra of both flavonol derivatives were obtained from a colloidal silver surface in physiological condition, based on the high performance of the enhanced substrate, the most enhanced modes of kaempferol and galangin were those with certain motions perpendicular to the metal surface. The SERS spectra were allowed to predict similar orientation geometry for both of the drugs on the colloidal surface with minor difference. In addition, both flavonols-HSA complexes were prepared in different concentration ratios and the orientated differences between kaempferol and galangin were investigated by SERS.

  14. SERS spectroscopy of kaempferol and galangin under the interaction of human serum albumin with adsorbed silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Bai, Xueyuan; Wang, Yingping; Zhao, Bing; Zhao, Daqing; Zhao, Yu

    Raman and surface-enhanced Raman scattering (SERS) spectroscopy were employed to probe the interaction of the flavonol drugs, kaempferol and galangin, with human serum albumin (HSA). SERS spectra of both flavonol derivatives were obtained from a colloidal silver surface in physiological condition, based on the high performance of the enhanced substrate, the most enhanced modes of kaempferol and galangin were those with certain motions perpendicular to the metal surface. The SERS spectra were allowed to predict similar orientation geometry for both of the drugs on the colloidal surface with minor difference. In addition, both flavonols-HSA complexes were prepared in different concentration ratios and the orientated differences between kaempferol and galangin were investigated by SERS.

  15. Gold@silver bimetal nanoparticles/pyramidal silicon 3D substrate with high reproducibility for high-performance SERS

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Jiang, Shou Zhen; Yang, Cheng; Li, Chong Hui; Huo, Yan Yan; Liu, Xiao Yun; Liu, Ai Hua; Wei, Qin; Gao, Sai Sai; Gao, Xing Guo; Man, Bao Yuan

    2016-05-01

    A novel and efficient surface enhanced Raman scattering (SERS) substrate has been presented based on Gold@silver/pyramidal silicon 3D substrate (Au@Ag/3D-Si). By combining the SERS activity of Ag, the chemical stability of Au and the large field enhancement of 3D-Si, the Au@Ag/3D-Si substrate possesses perfect sensitivity, homogeneity, reproducibility and chemical stability. Using R6G as probe molecule, the SERS results imply that the Au@Ag/3D-Si substrate is superior to the 3D-Si, Ag/3D-Si and Au/3D-Si substrate. We also confirmed these excellent behaviors in theory via a commercial COMSOL software. The corresponding experimental and theoretical results indicate that our proposed Au@Ag/3D-Si substrate is expected to develop new opportunities for label-free SERS detections in biological sensors, biomedical diagnostics and food safety.

  16. A General Method for Solvent Exchange of Plasmonic Nanoparticles and Self-Assembly into SERS-Active Monolayers

    PubMed Central

    2015-01-01

    We present a general route for the transfer of Au and Ag nanoparticles of different shapes and sizes, from water into various organic solvents. The experimental conditions for each type of nanoparticles were optimized by using a combination of thiolated poly(ethylene glycol) and a hydrophobic capping agent, such as dodecanethiol. The functionalized nanoparticles were readily transferred into organic dispersions with long-term stability (months). Such organic dispersions efficiently spread out on water, leading to self-assembly at the air/liquid interface into extended nanoparticle arrays which could in turn be transferred onto solid substrates. The dense close packing in the obtained nanoparticle monolayers results in extensive plasmon coupling, rendering them efficient substrates for surface-enhanced Raman scattering spectroscopy. PMID:26258732

  17. Organic-inorganic hybrid mesoporous polymers fabricated by using (CTA)2S2O8 as self-decomposed soft templates.

    PubMed

    Chen, Tianyou; Du, Binyang; Fan, Zhiqiang

    2012-10-23

    Organic-inorganic hybrid mesoporous polymers were successfully synthesized by using a template-directed free radical polymerization technique in aqueous solution at 0-5 °C with oxidative complexes as self-decomposed soft templates. The oxidative complexes ((CTA)(2)S(2)O(8)), which were formed between anionic oxidant (S(2)O(8)(2-)) and cationic surfactant (cetyltrimethylammonium bromide, CTAB) at 0-5 °C, can be automatically decomposed due to the reduction of S(2)O(8)(2-). No additional treatment was needed to remove the templates. The reactive functional monomer, 3-(trimethoxysilyl)propyl methacrylate (TMSPMA), was used as main monomer. Styrene was used as the comonomer. With simultaneous free radical copolymerization of TMSPMA and styrene, condensation of methoxysilyl groups, and the self-decomposition of (CTA)(2)S(2)O(8), organic-inorganic hybrid mesoporous polymers were successfully obtained. The mesoporous structures and morphologies of the resultant hybrid mesoporous polymers were found to be strongly dependent on the feed amounts of TMSPMA and styrene. In the absence of styrene, the hybrid polymer PTMSPMA exhibited mesh-like bicontinuous structures with mesopores and high surface area (335 m(2)/g). With the incorporation of styrene, mesoporous nanoparticles were obtained. The surface areas of the mesoporous nanoparticles decreased with the increase of styrene contents. The adsorption capabilities of such mesoporous polymers for organic dye (Congo red) and protein (bovine serum albumin) were also studied.

  18. Optical properties of dopamine molecules with silver nanoparticles as surface-enhanced raman scattering (SERS) substrates at different pH conditions.

    PubMed

    Bu, Yanru; Lee, Sang-Wha

    2013-09-01

    Silver nanoparticles (Ag NPs) prepared by the citrate reduction method were examined as surface-enhanced Raman scattering (SERS) substrates in the detection of dopamine (DA) molecules at different hydrogen ion concentrations. The aggregation of Ag NPs was influenced by the crosslinking effect of DA molecules as the function of pH of colloidal solution. Somewhat clustering of Ag NPs in a limited pH range (pH 7-9) exhibited the strong red-shift of absorption peak and maximal SERS activity to DA molecules, highlighting the importance of strong electrostatic adsorption and cross-linking effect that allowed DA molecules to reside in the junctions (hot spots) between aggregated Ag NPs. Furthermore, Ag NPs with DA molecules at strongly basic condition (> pH 9) exhibited the relatively high SERS activity as compared to negligible SERS activity at acidic condition (< or = pH 5), indicating the important role of oxidized surface of silver NPs which can interact with hydroxyl groups of DA molecules.

  19. Highly active surface-enhanced Raman scattering (SERS) substrates based on gold nanoparticles infiltrated into SiO2 inverse opals

    NASA Astrophysics Data System (ADS)

    Ankudze, Bright; Philip, Anish; Pakkanen, Tuula T.; Matikainen, Antti; Vahimaa, Pasi

    2016-11-01

    SiO2 inverse opal (IO) films with embedded gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) application are reported. SiO2 IO films were loaded with AuNPs by a simple infiltration in a single cycle to form Au-SiO2 IOs. The optical property and the morphology of the Au-SiO2 IO substrates were characterized; it was observed that they retained the Bragg diffraction of SiO2 IO and the localized surface plasmon resonance (LSPR) of AuNPs. The SERS property of the Au-SiO2 IO substrates were studied with methylene blue (MB) and 4-aminothiophenol (4-ATP). The SERS enhancement factors were 107 and 106 for 4-ATP and MB, respectively. A low detection limit of 10-10 M for 4-ATP was also obtained with the Au-SiO2 IO substrate. A relative standard deviation of 18.5% for the Raman signals intensity at 1077 cm-1 for 4-ATP shows that the Au-SiO2 IO substrates have good signal reproducibility. The results of this study indicate that the Au-SiO2 IO substrates can be used in sensing and SERS applications.

  20. Ag Nanoparticle-Grafted PAN-Nanohump Array Films with 3D High-Density Hot Spots as Flexible and Reliable SERS Substrates.

    PubMed

    Li, Zhongbo; Meng, Guowen; Huang, Qing; Hu, Xiaoye; He, Xuan; Tang, Haibin; Wang, Zhiwei; Li, Fadi

    2015-10-28

    A facile fabrication approach of large-scale flexible films is reported, with one surface side consisting of Ag-nanoparticle (Ag-NP) decorated polyacrylonitrile (PAN) nanohump (denoted as Ag-NPs@PAN-nanohump) arrays. This is achieved via molding PAN films with ordered nanohump arrays on one side and then sputtering much smaller Ag-NPs onto each of the PAN-nanohumps. Surface-enhanced Raman scattering (SERS) activity of the Ag-NPs@PAN-nanohump array films can be improved by curving the flexible PAN film with ordered nanohump arrays during the Ag-sputtering process to increase the density of the Ag-NPs on the sidewalls of the PAN-nanohumps. More 3D hot spots are thus achieved on a large-scale. The Ag-NPs@PAN-nanohump array films show high SERS activity with good Raman signal reproducibility for Rhodamine 6G probe molecules. To trial their practical application, the Ag-NPs@PAN-nanohump array films are employed as SERS substrates for trace detection of trinitrotoluene and a congener of polychlorinated biphenyls. A lower detection limit of 10(-12) m and 10(-5) m can be achieved, respectively. Furthermore, the flexible Ag-NPs@PAN-nanohump array films can also be utilized as swabs to probe traces of methyl parathion on the surface of fruits such as apples. The as-fabricated SERS substrates therefore have promising potential for applications in rapid safety inspection and environmental protection.

  1. 3D TiO{sub 2} submicrostructures decorated by silver nanoparticles as SERS substrate for organic pollutants detection and degradation

    SciTech Connect

    Chen, Jianjun; Su, Huilan; You, Xueling; Gao, Jing; Lau, Woon Ming; Zhang, Di

    2014-01-01

    Graphical abstract: - Highlights: • Contrive a multifunctional SERS substrate with 3D sub-micrometer structure and multicomponent. • The blue wing of butterfly (Euploea mulciber) is used as template for Ag/TiO{sub 2} nanocomposites. • The 3D submicrostructures Ag/TiO{sub 2} presents superior SERS effect and photocatalytic activity. • Pave a facile route to prepare multifunctional material by utilizing smart structural designs in nature. - Abstract: The blue wing of butterfly Euploea mulciber is used as a template to generate Ag/TiO{sub 2} nanocomposites. Thereinto, Ag nanoparticles are deposited uniformly onto TiO{sub 2} substrate with three dimensional (3D) submicrometer structures. This unique 3D sub-micrometer structures featured with ridges, ribs and struts can provide a large number of active “hot spots” for enhanced Raman signal. Meanwhile, depositing Ag onto the TiO{sub 2} surface can greatly boost its SERS effect and photocatalytic activity by bringing additional electrons into the molecules and inhibiting electrons–holes recombination. Thus, the as-prepared 3D Ag/TiO{sub 2} submicrostructures can not only offer sensitive and reproducible SERS signals, but also present superior photocatalytic activity, which can be utilized to detect and eliminate organic pollutants.

  2. Influence of substrate temperature on the properties of pulsed laser deposited silver nanoparticle thin films and their application in SERS detection of bovine serum albumin

    NASA Astrophysics Data System (ADS)

    Kamakshi, Koppole; Silva, J. P. B.; Sekhar, K. C.; Marslin, Gregory; Moreira, J. Agostinho; Conde, O.; Almeida, A.; Pereira, M.; Gomes, M. J. M.

    2016-05-01

    The effect of substrate temperature ( T s) on electrical conductance, surface plasmon resonance (SPR), and surface-enhanced Raman scattering (SERS) activity of silver nanoparticle (AgNP) thin films is presented. AgNP films are grown on glass substrates by pulsed laser deposition in a controlled Ar atmosphere at a pressure of 0.1 mbar and varying T s. Different T s results in different morphologies, as observed by scanning electron microscopy. The effect of interparticle distance on the electrical conductance of AgNPs is highlighted. The current-voltage characteristics display negative resistance effect and is attributed to the charge trapping process in AgNPs. The film deposited at room temperature presents a SPR peak at λ = 460 nm, and its wavelength first increases until T s reaches 300 °C and then decreases with further increasing T s. The quantitative analysis of SERS studies reveals that SERS intensity of bovine serum albumin (BSA) adsorbed on AgNP substrate deposited at 300 °C exhibits a higher intensity as compared with that of BSA adsorbed on the SERS active substrates at any other T s.

  3. Intuitive Label-Free SERS Detection of Bacteria Using Aptamer-Based in Situ Silver Nanoparticles Synthesis.

    PubMed

    Gao, Weicun; Li, Bo; Yao, Ruizhi; Li, Zhiping; Wang, Xiwen; Dong, Xiaolin; Qu, Han; Li, Qianxue; Li, Nan; Chi, Hang; Zhou, Bo; Xia, Zhiping

    2017-09-19

    The characteristic of an ideal bacteria-detection method should have high sensitivity and specificity, be easy to operate, and not have a time-consuming culture process. In this study, we report a new bacteria-detection strategy that can recognize bacteria quickly and directly by surface-enhanced Raman scattering (SERS) with the formation of well-defined bacteria-aptamer@AgNPs. SERS signals generated by bacteria-aptamer@AgNPs exhibited a linear dependence on bacteria (R(2) = 0.9671) concentration ranging from 10(1) to 10(7) cfu/mL. The detection limit is sensitive down to 1.5 cfu/mL. Meanwhile, the bacteria SERS signal was dramatically enhanced by its specifically recognized aptamer, and the bacteria could be identified directly and visually through the SERS spectrum. This strategy eliminates the puzzling data analysis of previous studies and offers significant advantages over existing approaches, getting a critical step toward the creation of SERS-based biochips for rapid in situ bacteria detection in mixture samples.

  4. Highly uniform and optical visualization of SERS substrate for pesticide analysis based on Au nanoparticles grafted on dendritic α-Fe2O3

    NASA Astrophysics Data System (ADS)

    Tang, Xianghu; Cai, Wenya; Yang, Liangbao; Liu, Jinhuai

    2013-10-01

    Here, Au nanoparticles (NPs) grafted on dendritic α-Fe2O3 (NPGDF) are designed as a highly uniform surface-enhanced Raman scattering (SERS) substrate with a feature of optical visualization by an optical microscope (OM) system and used for in situ detection of pesticide residues that are annually used in agriculture. With this strategy, the dendritic α-Fe2O3 has been synthesized by a hydrothermal method and significantly functionalized by an inductively coupled plasma (ICP) apparatus and then Au NPs were grafted on it densely and uniformly. In addition, the profile of NPGDF can be clearly observed using an OM platform of a Raman spectrometer, and the profile of SERS spectral mapping with NPGDF as substrate almost exactly coincides with the OM image, the electron microscope (EM) image and the elemental mapping of NPGDF, which indicates remarkable uniformity of the NPGDF as SERS substrate, thus ensuring the laser beam focuses on the efficient sites of the substrate under the OM platform. Moreover, NPGDF can be dispersed in the liquor and the NPGDF microparticles can be adsorbed on the target surface. Therefore, it can be used for in situ detection of pesticide residues on tea leaves, fruits etc., with high sensitivity and reproducibility.Here, Au nanoparticles (NPs) grafted on dendritic α-Fe2O3 (NPGDF) are designed as a highly uniform surface-enhanced Raman scattering (SERS) substrate with a feature of optical visualization by an optical microscope (OM) system and used for in situ detection of pesticide residues that are annually used in agriculture. With this strategy, the dendritic α-Fe2O3 has been synthesized by a hydrothermal method and significantly functionalized by an inductively coupled plasma (ICP) apparatus and then Au NPs were grafted on it densely and uniformly. In addition, the profile of NPGDF can be clearly observed using an OM platform of a Raman spectrometer, and the profile of SERS spectral mapping with NPGDF as substrate almost exactly

  5. A rapid green strategy for the synthesis of Au "meatball"-like nanoparticles using green tea for SERS applications

    NASA Astrophysics Data System (ADS)

    Wu, Shichao; Zhou, Xi; Yang, Xiangrui; Hou, Zhenqing; Shi, Yanfeng; Zhong, Lubin; Jiang, Qian; Zhang, Qiqing

    2014-09-01

    We report a simple and rapid biological approach to synthesize water-soluble and highly roughened "meatball"-like Au nanoparticles using green tea extract under microwave irradiation. The synthesized Au meatball-like nanoparticles possess excellent monodispersity and uniform size (250 nm in diameter). Raman measurements show that these tea-generated meatball-like gold nanostructures with high active surface areas exhibit a high enhancement of surface-enhanced Raman scattering. In addition, the Au meatball-like nanoparticles demonstrate good biocompatibility and remarkable in vitro stability at the biological temperature. Meanwhile, the factors that influence the Au meatball-like nanoparticles morphology are investigated, and the mechanisms behind the nonspherical shape evolution are discussed.

  6. Organic/inorganic hybrid amine and sulfonic acid tethered silica materials: Synthesis, characterization and application

    NASA Astrophysics Data System (ADS)

    Hicks, Jason Christopher

    The major goals of this thesis were to: (1) create a site-isolated aminosilica material with higher amine loadings than previously reported isolation methods, (2) use spectroscopic, reactivity, and catalytic (olefin polymerization precatalysts) probes to determine isolation of amine groups on these organic/inorganic hybrid materials, (3) synthesize an organic/inorganic hybrid material capable of activating Group 4 olefin polymerization precatalysts, and (4) synthesize a high amine loaded organic/inorganic hybrid material capable of reversibly capturing CO2 in a simulated flue gas stream. The underlying motivation of this research involved the synthesis and design of novel amine and sulfonic acid materials. Traditional routes to synthesize aminosilicas have led to the formation of a high loading of multiple types of amine sites on the silica surface. Part of this research involved the creation of a new aminosilica material via a protection/deprotection method designed to prevent multiple sites, while maintaining a relatively high loading. As a characterization technique, fluorescence spectroscopy of pyrene-based fluorophores loaded on traditional aminosilicas and site-isolated aminosilicas was used to probe the degree of site-isolation obtained with these methods. Also, this protection/deprotection method was compared to other reported isolation techniques with heterogeneous Group 4 constrained-geometry inspired catalysts (CGCs). It was determined that the degree of separation of the amine sites could be controlled with protection/deprotection methods. Furthermore, an increase in the reactivity of the amines and the catalytic activity of CGCs built off of the amines was determined for aminosilicas synthesized by a protection/deprotection method. The second part of this work involved developing organic/inorganic hybrid materials as heterogeneous Bronsted acidic cocatalysts for activation of olefin polymerization precatalysts. This was the first reported organic/inorganic

  7. Supported catalysts using nanoparticles as the support material

    DOEpatents

    Wong, Michael S.; Wachs, Israel E.; Knowles, William V.

    2010-11-02

    A process for making a porous catalyst, comprises a) providing an aqueous solution containing a nanoparticle precursor, b) forming a composition containing nanoparticles, c) adding a first catalytic component or precursor thereof and a pore-forming agent to the composition containing nanoparticles and allowing the first catalytic component, the pore-forming agent, and the nanoparticles form an organic-inorganic structure, d) removing water from the organic-inorganic structure; and e) removing the pore-forming agent from the organic-inorganic structure so as to yield a porous catalyst.

  8. High-energy X-ray detection by hafnium-doped organic-inorganic hybrid scintillators prepared by sol-gel method

    SciTech Connect

    Sun, Yan; Koshimizu, Masanori Yahaba, Natsuna; Asai, Keisuke; Nishikido, Fumihiko; Kishimoto, Shunji; Haruki, Rie

    2014-04-28

    With the aim of enhancing the efficiency with which plastic scintillators detect high-energy X-rays, hafnium-doped organic-inorganic hybrid scintillators were fabricated via a sol-gel method. Transmission electron microscopy of sampled material reveals the presence of Hf{sub x}Si{sub 1−x}O{sub 2} nanoparticles, dispersed in a polymer matrix that constitutes the active material of the X-ray detector. With Hf{sub x}Si{sub 1−x}O{sub 2} nanoparticles incorporated in the polymer matrix, the absorption edge and the luminescence wavelength is shifted, which we attribute to Mie scattering. The detection efficiency for 67.4-keV X-rays in a 0.6-mm-thick piece of this material is two times better than the same thickness of a commercial plastic scintillator-NE142.

  9. Highly selective SERS probe for Hg(II) detection using tryptophan-protected popcorn shaped gold nanoparticles.

    PubMed

    Senapati, Tapas; Senapati, Dulal; Singh, Anant Kumar; Fan, Zhen; Kanchanapally, Rajashekhar; Ray, Paresh Chandra

    2011-10-07

    Contamination of the environment with toxic Hg(II) is becoming a huge concern throughout the world now. Driven by the need, this communication reports for the first time a tryptophan protected popcorn shaped gold nanomaterials based SERS probe for rapid, easy and highly selective recognition of Hg(II) ions in the 5 ppb level from aqueous solution, with high sensitivity and selectivity over competing analytes. We demonstrate that our SERS assay is capable of measuring the amount of Hg(II) in alkaline battery. This journal is © The Royal Society of Chemistry 2011

  10. Multimodal assessment of SERS nanoparticle biodistribution post ingestion reveals new potential for clinical translation of Raman imaging.

    PubMed

    Campbell, Jos L; SoRelle, Elliott D; Ilovich, Ohad; Liba, Orly; James, Michelle L; Qiu, Zhen; Perez, Valerie; Chan, Carmel T; de la Zerda, Adam; Zavaleta, Cristina

    2017-08-01

    Despite extensive research and development, new nano-based diagnostic contrast agents have faced major barriers in gaining regulatory approval due to their potential systemic toxicity and prolonged retention in vital organs. Here we use five independent biodistribution techniques to demonstrate that oral ingestion of one such agent, gold-silica Raman nanoparticles, results in complete clearance with no systemic toxicity in living mice. The oral delivery mimics topical administration to the oral cavity and gastrointestinal (GI) tract as an alternative to intravenous injection. Biodistribution and clearance profiles of orally (OR) vs. intravenously (IV) administered Raman nanoparticles were assayed over the course of 48 h. Mice given either an IV or oral dose of Raman nanoparticles radiolabeled with approximately 100 μCi (3.7MBq) of (64)Cu were imaged with dynamic microPET immediately post nanoparticle administration. Static microPET images were also acquired at 2 h, 5 h, 24 h and 48 h. Mice were sacrificed post imaging and various analyses were performed on the excised organs to determine nanoparticle localization. The results from microPET imaging, gamma counting, Raman imaging, ICP-MS, and hyperspectral imaging of tissue sections all correlated to reveal no evidence of systemic distribution of Raman nanoparticles after oral administration and complete clearance from the GI tract within 24 h. Paired with the unique signals and multiplexing potential of Raman nanoparticles, this approach holds great promise for realizing targeted imaging of tumors and dysplastic tissues within the oral cavity and GI-tract. Moreover, these results suggest a viable path for the first translation of high-sensitivity Raman contrast imaging into clinical practice. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Zero-Dimensional Hybrid Organic-Inorganic Halide Perovskite Modeling: Insights from First Principles.

    PubMed

    Giorgi, Giacomo; Yamashita, Koichi

    2016-03-03

    We discuss the properties of zero dimensional (cluster) hybrid organic-inorganic halide perovskite in view of their possible applicability in photovoltaics, light-emitting, and lasing devices. To support the need of theoretical investigations of such systems and pave the way for future investigations of clusters with different orientations, terminations, and compositions, we have assembled and characterized some zero dimensional models of methylammonium lead iodide, MAPbI3, by "cutting" its bulk. Interesting properties of such clusters that have been here theoretically investigated include their charge distribution, bandgap, wave function localization, and reduced effective mass. The surface orientation/termination and the organic/inorganic cation ratios have been discussed together with the roles they play in determining the electronic properties of such clusters. Also in agreement with experiments, it emerges that surface termination is crucial in determining the structural and optoelectronic properties of this largely overlooked, dimensionally reduced class of materials. Analogies and differences between clusters and bulk are discussed.

  12. Efficient Organic/Inorganic Hybrid Solar Cell Integrating Polymer Nanowires and Inorganic Nanotetrapods.

    PubMed

    Xu, Weizhe; Tan, Furui; Liu, Xiansheng; Zhang, Weifeng; Qu, Shengchun; Wang, Zhijie; Wang, Zhanguo

    2017-12-01

    Constructing a highly efficient bulk-heterojunction is of critical importance to the hybrid organic/inorganic solar cells. Here in this work, we introduce a novel hybrid architecture containing P3HT nanowire and CdSe nanotetrapod as bicontinuous charge channels for holes and electrons, respectively. Compared to the traditionally applied P3HT molecules, the well crystallized P3HT nanowires qualify an enhanced light absorption at the long wavelength as well as strengthened charge carrier transport in the hybrid active layer. Accordingly, based on efficient dissociation of photogenerated excitons, the interpercolation of these two nano-building blocks allows a photovoltaic conversion efficiency of 1.7% in the hybrid solar cell, up to 42% enhancement compared to the reference solar cell with traditional P3HT molecules as electron donor. Our work provides a promising hybrid structure for efficient organic/inorganic bulk-heterojunction solar cells.

  13. Electric-Magneto-Optical Kerr Effect in a Hybrid Organic-Inorganic Perovskite.

    PubMed

    Fan, Feng-Ren; Wu, Hua; Nabok, Dmitrii; Hu, Shunbo; Ren, Wei; Draxl, Claudia; Stroppa, Alessandro

    2017-09-20

    Hybrid organic-inorganic compounds attract a lot of interest for their flexible structures and multifunctional properties. For example, they can have coexisting magnetism and ferroelectricity whose possible coupling gives rise to magnetoelectricity. Here using first-principles computations, we show that, in a perovskite metal-organic framework (MOF), the magnetic and electric orders are further coupled to optical excitations, leading to an Electric tuning of the Magneto-Optical Kerr effect (EMOKE). Moreover, the Kerr angle can be switched by reversal of both ferroelectric and magnetic polarization only. The interplay between the Kerr angle and the organic-inorganic components of MOFs offers surprising unprecedented tools for engineering MOKE in complex compounds. Note that this work may be relevant to acentric magnetic systems in general, e.g., multiferroics.

  14. Fabrication of organic-inorganic perovskite thin films for planar solar cells via pulsed laser deposition

    SciTech Connect

    Liang, Yangang; Zhang, Xiaohang; Gong, Yunhui; Shin, Jongmoon; Wachsman, Eric D.; Takeuchi, Ichiro; Yao, Yangyi; Hsu, Wei-Lun; Dagenais, Mario

    2016-01-15

    We report on fabrication of organic-inorganic perovskite thin films using a hybrid method consisting of pulsed laser deposition (PLD) of lead iodide and spin-coating of methylammonium iodide. Smooth and highly crystalline CH{sub 3}NH{sub 3}PbI{sub 3} thin films have been fabricated on silicon and glass coated substrates with fluorine doped tin oxide using this PLD-based hybrid method. Planar perovskite solar cells with an inverted structure have been successfully fabricated using the perovskite films. Because of its versatility, the PLD-based hybrid fabrication method not only provides an easy and precise control of the thickness of the perovskite thin films, but also offers a straightforward platform for studying the potential feasibility in using other metal halides and organic salts for formation of the organic-inorganic perovskite structure.

  15. Efficient Organic/Inorganic Hybrid Solar Cell Integrating Polymer Nanowires and Inorganic Nanotetrapods

    NASA Astrophysics Data System (ADS)

    Xu, Weizhe; Tan, Furui; Liu, Xiansheng; Zhang, Weifeng; Qu, Shengchun; Wang, Zhijie; Wang, Zhanguo

    2017-01-01

    Constructing a highly efficient bulk-heterojunction is of critical importance to the hybrid organic/inorganic solar cells. Here in this work, we introduce a novel hybrid architecture containing P3HT nanowire and CdSe nanotetrapod as bicontinuous charge channels for holes and electrons, respectively. Compared to the traditionally applied P3HT molecules, the well crystallized P3HT nanowires qualify an enhanced light absorption at the long wavelength as well as strengthened charge carrier transport in the hybrid active layer. Accordingly, based on efficient dissociation of photogenerated excitons, the interpercolation of these two nano-building blocks allows a photovoltaic conversion efficiency of 1.7% in the hybrid solar cell, up to 42% enhancement compared to the reference solar cell with traditional P3HT molecules as electron donor. Our work provides a promising hybrid structure for efficient organic/inorganic bulk-heterojunction solar cells.

  16. Energetics and dynamics in organic-inorganic halide perovskite photovoltaics and light emitters

    NASA Astrophysics Data System (ADS)

    Chien Sum, Tze; Chen, Shi; Xing, Guichuan; Liu, Xinfeng; Wu, Bo

    2015-08-01

    The rapid transcendence of organic-inorganic metal halide perovskite solar cells to above the 20% efficiency mark has captivated the broad photovoltaic community. As the efficiency race continues unabated, it is essential that fundamental studies keep pace with these developments. Further gains in device efficiencies are expected to be increasingly arduous and harder to come by. The key to driving the perovskite solar cell efficiencies towards their Shockley-Queisser limit is through a clear understanding of the interfacial energetics and dynamics between perovskites and other functional materials in nanostructured- and heterojunction-type devices. In this review, we focus on the current progress in basic characterization studies to elucidate the interfacial energetics (energy-level alignment and band bending) and dynamical processes (from the ultrafast to the ultraslow) in organic-inorganic metal halide perovskite photovoltaics and light emitters. Major findings from these studies will be distilled. Open questions and scientific challenges will also be highlighted.

  17. Organic-inorganic hybrid gels for the selective absorption of oils from water.

    PubMed

    Ozan Aydin, Gulsah; Bulbul Sonmez, Hayal

    2016-06-01

    Organic-inorganic hybrid gels were synthesized by the condensation of a linear aliphatic diol (1,8-octanediol) and altering the chain length of the alkyltriethoxysilanes (from ethyltriethoxysilane to hexadecyltrimethoxysilane) through a bulk polymerization process without using any initiator, activator, catalyst, or solvent for the selective removal of oils from water. Fourier transform infrared spectroscopy (FTIR) and solid-state (13)C and (29)Si cross-polarization magic-angle spinning nuclear magnetic resonance (CPMAS NMR) were used for the structural analysis of hybrid gels. Thermal properties of the hybrid gels were determined by thermogravimetric analysis (TGA). Oil absorbency of organic-inorganic hybrid gels was determined by oil absorption tests. The results showed that hybrid gels have high and fast absorption capacities and excellent reusability. Good selectivity, high thermal stability, low density, and excellent recyclability for the oil removal give the material potential applications.

  18. A novel organic-inorganic hybrid tandem solar cell with inverted structure

    NASA Astrophysics Data System (ADS)

    Bahrami, A.; Faez, R.

    2017-04-01

    A novel organic-inorganic hybrid tandem solar cell with inverted structure is proposed. This efficient double-junction hybrid tandem solar cell consists of a single-junction hydrogenated amorphous silicon (a-Si:H) subcell with n-i-p structure as front cell and a P3HT:PCBM organic subcell with inverted structure as back cell. In order to optimize the hybrid tandem cell, we have performed a simulation based on transfer matrix method. We have compared the characteristics of this novel structure with a conventional structure. As a result, a power conversion efficiency (PCE) of 6.1 and 24% improvement compared to the conventional hybrid tandem cell was achieved. We also discuss the high potential of this novel structure for realizing high-stability organic-inorganic hybrid photovoltaic devices.

  19. Fabrication of organic-inorganic perovskite thin films for planar solar cells via pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Liang, Yangang; Yao, Yangyi; Zhang, Xiaohang; Hsu, Wei-Lun; Gong, Yunhui; Shin, Jongmoon; Wachsman, Eric D.; Dagenais, Mario; Takeuchi, Ichiro

    2016-01-01

    We report on fabrication of organic-inorganic perovskite thin films using a hybrid method consisting of pulsed laser deposition (PLD) of lead iodide and spin-coating of methylammonium iodide. Smooth and highly crystalline CH3NH3PbI3 thin films have been fabricated on silicon and glass coated substrates with fluorine doped tin oxide using this PLD-based hybrid method. Planar perovskite solar cells with an inverted structure have been successfully fabricated using the perovskite films. Because of its versatility, the PLD-based hybrid fabrication method not only provides an easy and precise control of the thickness of the perovskite thin films, but also offers a straightforward platform for studying the potential feasibility in using other metal halides and organic salts for formation of the organic-inorganic perovskite structure.

  20. High Open-Circuit Voltage Solar Cells Based on Organic-Inorganic Lead Bromide Perovskite.

    PubMed

    Edri, Eran; Kirmayer, Saar; Cahen, David; Hodes, Gary

    2013-03-21

    Mesoscopic solar cells, based on solution-processed organic-inorganic perovskite absorbers, are a promising avenue for converting solar to electrical energy. We used solution-processed organic-inorganic lead halide perovskite absorbers, in conjunction with organic hole conductors, to form high voltage solar cells. There is a dire need for low-cost cells of this type, to drive electrochemical reactions or as the high photon energy cell in a system with spectral splitting. These perovskite materials, although spin-coated from solution, form highly crystalline materials. Their simple synthesis, along with high chemical versatility, allows tuning their electronic and optical properties. By judicious selection of the perovskite lead halide-based absorber, matching organic hole conductor, and contacts, a cell with a ∼ 1.3 V open circuit voltage was made. While further study is needed, this achievement provides a general guideline for additional improvement of cell performance.

  1. Silver nanoparticle decorated reduced graphene oxide (rGO) nanosheet: a platform for SERS based low-level detection of uranyl ion.

    PubMed

    Dutta, Soumen; Ray, Chaiti; Sarkar, Sougata; Pradhan, Mukul; Negishi, Yuichi; Pal, Tarasankar

    2013-09-11

    Herein, a simple wet-chemical pathway has been demonstrated for the synthesis of silver nanoparticle conjugated reduced graphene oxide nanosheets where dimethylformamide (DMF) is judiciously employed as an efficient reducing agent. Altogether, DMF reduces both silver nitrate (AgNO3) and graphene oxide (GO) in the reaction mixture. Additionally, the presence of polyvinylpyrolidone (PVP) assists the nanophasic growth and homogeneous distribution of the plasmonic nanoparticle Ag(0). Reduction of graphene oxide and the presence of aggregated Ag NPs on reduced graphene oxide (rGO) nanosheets are confirmed from various spectroscopic techniques. Finally, the composite material has been exploited as an intriguing platform for surface enhanced Raman scattering (SERS) based selective detection of uranyl (UO2(2+)) ion. The limit of detection has been achieved to be as low as 10 nM. Here the normal Raman spectral (NRS) band of uranyl acetate (UAc) at 838 cm(-1) shifts to 714 and 730 cm(-1) as SERS bands for pH 5.0 and 12.0, respectively. This distinguished Raman shift of the symmetric stretching mode for UO2(2+) ion is indicative of pronounced charge transfer (CT) effect. This CT effect even supports the higher sensitivity of the protocol toward UO2(2+) over other tested oxo-ions. It is anticipated that rGO nanosheets furnish a convenient compartment to favor the interaction between Ag NPs and UO2(2+) ion through proximity induced adsorption even at low concentration.

  2. Tuning gold nanoparticles interfaces by specific peptide interaction for surface enhanced Raman spectroscopy (SERS) and separation applications.

    PubMed

    Manikas, Anastasios C; Causa, Filippo; Della Moglie, Raffaella; Netti, Paolo A

    2013-08-28

    Surface functionalization and control over nanostructured interfaces represents a key aspect in nanoscience and nanobiotechnology. Nanoplasmonic structures for analyte detection typically require sophisticated nanofabrication techniques, as well as bioactivated nanostructures that need multistep conjugations for chemical ligation. An alternative to such complex processes is to rely on specific biomolecules adsorption for decoration or self-assembly of nanoparticles at solid/liquid interface. In principle, small biomolecules with specific binding properties to nanostructures could control the assembly without modifying the nanoparticle chemistry, pH of the solution or salt concentration. Importantly, such an approach could be direct, robust, and reversible. In this work, we report about the use of a specific peptide for direct and reversible adsorption on gold nanoparticles with tuned interfacial properties just by simply adjusting the ratio between the numbers of peptide molecules to the number of gold nanoparticles. This easy, direct and reversible assembly of gold nanoparticles mediated by the specific peptide makes this platform ideal for small-volume samples and low concentrations detection using surface enhanced Raman Spectroscopy, as well as for the capture or separation of biomolecules in complex mix.

  3. Solution-Processed Organic-Inorganic Perovskite Field-Effect Transistors with High Hole Mobilities.

    PubMed

    Matsushima, Toshinori; Hwang, Sunbin; Sandanayaka, Atula S D; Qin, Chuanjiang; Terakawa, Shinobu; Fujihara, Takashi; Yahiro, Masayuki; Adachi, Chihaya

    2016-12-01

    A very high hole mobility of 15 cm(2) V(-1) s(-1) along with negligible hysteresis are demonstrated in transistors with an organic-inorganic perovskite semiconductor. This high mobility results from the well-developed perovskite crystallites, improved conversion to perovskite, reduced hole trap density, and improved hole injection by employing a top-contact/top-gate structure with surface treatment and MoOx hole-injection layers.

  4. Multisite organic-inorganic hybrid catalysts for the direct sustainable synthesis of GABAergic drugs.

    PubMed

    Leyva-Pérez, Antonio; García-García, Pilar; Corma, Avelino

    2014-08-11

    Multisite organic-inorganic hybrid catalysts have been prepared and applied in a new general, practical, and sustainable synthetic procedure toward industrially relevant GABA derivatives. The domino sequence is composed of seven chemical transformations which are performed in two one-pot reactions. The method produces both enantiomeric forms of the product in high enantiopurity as well as the racemate in good yields after a single column purification step. This protocol highlights major process intensification, catalyst recyclability, and low waste generation.

  5. Organic-inorganic nanostructures for luminescent indication in the near-infrared range

    NASA Astrophysics Data System (ADS)

    Kondratenko, T. S.; Ovchinnikov, O. V.; Grevtseva, I. G.; Smirnov, M. S.

    2016-04-01

    Amplifying and quenching of IR luminescence of colloidal Ag2S quantum dots were revealed to take place when they couple to organic dye molecules of 3,3'-di-(γ-sulfopropyl)-9-ethyl-4,5,4',5'-dibenzothiacarbocyanine betaine and erytrosine pyridinium salts, respectively. The observed effects are explained as due to the formation of organic-inorganic heterostructures with different mutual arrangement of electronic states of the dyes and the quantum dots.

  6. Organic/inorganic hybrid pn-junction between copper phthalocyanine and CdSe quantum dot layers as solar cells

    NASA Astrophysics Data System (ADS)

    Saha, Sudip K.; Guchhait, Asim; Pal, Amlan J.

    2012-08-01

    We have introduced an organic/inorganic hybrid pn-junction for solar cell applications. Layers of II-VI quantum dots and a metal-phthalocyanine in sequence have been used as n- and p-type materials, respectively, to form a junction. The film of quantum dots has been formed through a layer-by-layer process by replacing the long-chain ligands of the nanoparticles in each ultrathin layer or a monolayer with short-chain ones so that interparticle distance becomes small leading to a decrease in resistance of the quantum dot layer. With indium tin oxide and Au as electrodes, we have formed an inverted sandwiched structure. These electrodes formed ohmic contacts with the neighboring materials. From the current-voltage characteristics of the hybrid heterostructure, we have inferred formation of a depletion region at the pn-junction that played a key role in charge separation and correspondingly a photocurrent in the external circuit. For comparison, we have also formed and characterized Schottky devices based on components of the pn-junction keeping the electrode combination same. From capacitance-voltage characteristics, we have observed that the depletion region of the hybrid pn-junction was much wider as compared to that in Schottky devices based on components of the junction.

  7. CdSe/ZnS quantum dot size dependent carrier relaxation in hybrid organic/inorganic system.

    PubMed

    Uddin, A; Wong, H S; Teo, C C

    2012-10-01

    We have studied the CdSe/ZnS quantum dot (QD) size dependent carrier relaxation dynamics in hybrid organic/inorganic system for the first time. The QD size was from 5.0 to 2.0 nm. The optical narrow emission of quantum dots shift to higher energies as the size of dots gets smaller due to the 3-D confinement which splits the continuous band into a series of discrete quantum states and increases the band gap. The carrier relaxation time in QDs was found to increases as the pump power increased and reached saturation at approximately 326 microW excitation, probably due to the saturation of traps with the photoexcited charge carriers within individual nanoparticles. The relaxation rate was also increased with pump power, indicating that new relaxation processes e.g., Auger processes and faster carrier trapping were present. The slow decay component remained at the lowest power (51microW) excitation with no fast decay present. The decrease of CdSe/ZnS QD size increased the fast component relaxation rate probably due to a higher number of surface defects hence inducing faster trapping of carriers by shallow trap state.

  8. Development of a sodium alginate-based organic/inorganic superabsorbent composite hydrogel for adsorption of methylene blue.

    PubMed

    Thakur, Sourbh; Pandey, Sadanand; Arotiba, Omotayo A

    2016-11-20

    Batch adsorption experiments were carried out for the removal of methylene blue (MB) cationic dye from aqueous solution using organic/inorganic hydrogel nanocomposite of titania incorporated sodium alginate crosslinked polyacrylic acid (SA-cl-poly(AA)-TiO2). The hydrogel was prepared by graft copolymerization of acrylic acid (AA) onto sodium alginate (SA) biopolymer in the presence of a crosslinking agent, a free radical initiator and TiO2 nanoparticles. The hydrogel exhibited a high swelling capacity of 412.98g/g. The factors influencing adsorption capacity of the absorbents such as pH of the dye solutions, initial concentration of the dye, amount of absorbents, and temperature were investigated and used to propose a possible mechanism of adsorption. The adsorption process concurs with a pseudo-second-order kinetics and with Langmuir isotherm equation. A very high adsorption capacity (Qmax=2257.36 (mg/g)) and a correlation coefficient of 0.998 calculated from isotherm equations show the high efficiency of the absorbent and thus expected to be a good candidate as an absorbent for water treatment.

  9. A versatile SERS-based immunoassay for immunoglobulin detection using antigen-coated gold nanoparticles and malachite green-conjugated protein A/G.

    PubMed

    Neng, Jing; Harpster, Mark H; Zhang, Hao; Mecham, James O; Wilson, William C; Johnson, Patrick A

    2010-11-15

    A surface enhanced Raman scattering (SERS) immunoassay for antibody detection in serum is described in the present work. The developed assay is conducted in solution and utilizes Au nanoparticles coated with the envelope (E) protein of West Nile Virus (WNV) as the SERS-active substrate and malachite green (MG)-conjugated protein A/G (MG-pA/G) as a bi-functional Raman tag/antibody binding reporter. Upon incubation of these reagents with serum collected from rabbits inoculated with E antigen, laser interrogation of the sandwiched immunocomplex revealed a SERS signaling response diagnostic for MG. The intensification of signature spectral peaks is shown to be proportionate to the concentration of added serum and the limit of antibody detection is 2 ng/ml of serum. To assess assay performance relative to more a traditional immunoassay, indirect enzyme-linked immunosorbent assays conducted using the same concentrations of reagents were found to be >400-fold less sensitive. Quartz crystal microbalance with dissipation (QCM-D) monitoring of immunocomplex film deposition on solid Au surfaces also confirmed the formation of antigen-antibody-protein A/G trilayers and provided quantitative measurements of film thickness which likely position MG within the sensing distance of laser-elicited, enhanced electromagnetic fields. The sensitivity and inherent versatility of the assay, which is provided by the binding of pA/G to a broad spectrum of immunoglobulins in different mammalian species, suggest that it could be developed as an alternative immunoassay format to the ELISA.

  10. Utility of surface enhanced Raman spectroscopy (SERS) for elucidation and simultaneous determination of some penicillins and penicilloic acid using hydroxylamine silver nanoparticles.

    PubMed

    El-Zahry, Marwa R; Refaat, Ibrahim H; Mohamed, Horria A; Rosenberg, Erwin; Lendl, Bernhard

    2015-11-01

    Elucidation and quantitative determination of some of commonly used penicillins (ampicillin, penicillin G and carbenicillin) in the presence of their main degradation product (penicilloic acid) were developed. Forced acidic and basic degradation processes were applied at different time intervals. The formed degradation products were elucidated and quantified using surface enhanced Raman spectroscopy (SERS). Silver nanoparticles (AgNPs) prepared by reduction of silver nitrate using hydroxylamine-HCl in alkaline medium were used as SERS substrate. The results obtained in SERS were confirmed by the application of LC/MS method. The concentration range was 100-600 ng/ml in case of the studied penicillins and 100-700 ng/ml in case of penicilloic acid. An excellent correlation coefficient was found in case of ampicillin (r=0.9993) and in the case of penicilloic acid (r=0.9997). Validation procedures were carried out including precision, robustness and accuracy by comparing F- and t-values of both the proposed and reported methods. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Preparation and applications of hybrid organic-inorganic monoliths: a review.

    PubMed

    Zhu, Tao; Row, Kyung Ho

    2012-06-01

    This review presents an overview of the properties of hybrid organic-inorganic monolithic materials and summarizes the recent developments in the preparation and applications of these hybrid monolithic materials. Hybrid monolithic materials with porosities, surface functionalities, and fast dynamic transport have developed rapidly, and have been used in a wide range of applications owing to the low cost, good stability, and excellent performance. Basically, these materials can be divided into two major types according to the chemical composition: hybrid silica-based monolith (HSM) and hybrid polymer-based monolith (HPM). Compared to the HPM, HSM monolith has been attracting most wide attentions, and it is commonly synthesized by the sol-gel process. The conventional preparation procedures of two type's hybrid organic-inorganic monoliths are addressed. Applications of hybrid organic-inorganic monoliths in optical devices, capillary microextraction (CME), capillary electrochromatography (CEC), high performance liquid chromatography (HPLC), and chiral separation are also reviewed. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. [Effects of organic-inorganic mixed fertilizers on rice yield and nitrogen use efficiency].

    PubMed

    Zhang, Xiao-li; Meng, Lin; Wang, Qiu-jun; Luo, Jia; Huang, Qi-wei; Xu, Yang-chun; Yang, Xing-ming; Shen, Qi-rong

    2009-03-01

    A field experiment was carried to study the effects of organic-inorganic mixed fertilizers on rice yield, nitrogen (N) use efficiency, soil N supply, and soil microbial diversity. Rapeseed cake compost (RCC), pig manure compost (PMC), and Chinese medicine residue compost (MRC) were mixed with chemical N, P and K fertilizers. All the treatments except CK received the same rate of N. The results showed that all N fertilizer application treatments had higher rice yield (7918.8-9449.2 kg x hm(-2)) than the control (6947.9 kg x hm(-2)). Compared with that of chemical fertilizers (CF) treatment (7918.8 kg x hm(-2)), the yield of the three organic-inorganic mixed fertilizers treatments ranged in 8532.0-9449.2 kg x hm(-2), and the increment was 7.7%-19.3%. Compared with treatment CF, the treatments of organic-inorganic mixed fertilizers were significantly higher in N accumulation, N transportation efficiency, N recovery rate, agronomic N use efficiency, and physiological N use efficiency. These mixed fertilizers treatments promoted rice N uptake and improved soil N supply, and thus, increased N use efficiency, compared with treatments CF and CK. Neighbor joining analysis indicated that soil bacterial communities in the five treatments could be classified into three categories, i.e., CF and CK, PMC and MRC, and RCC, implying that the application of exogenous organic materials could affect soil bacterial communities, while applying chemical fertilizers had little effect on them.

  13. 45S5 Bioglass®-derived scaffolds coated with organic-inorganic hybrids containing graphene.

    PubMed

    Fabbri, Paola; Valentini, Luca; Hum, Jasmin; Detsch, Rainer; Boccaccini, Aldo R

    2013-10-01

    Highly porous 45S5 Bioglass®-based scaffolds fabricated by a foam replication technique were coated with electrically conductive organic-inorganic hybrid layers containing graphene by a solution method. α,ω-Triethoxysilane terminated poly (ethylene glycol) and tetraethoxysilane were used as the precursors of the organic-inorganic hybrid coatings, that contained 1.5 wt.% of homogeneously dispersed graphene nanoplatelets. The resulting coated scaffolds retained their original high porosity and interconnected pore structure after coating. The presence of graphene did not impair the bioactivity of the scaffolds in simulated body fluid. Initial tests carried out using MG-63 cells demonstrated that both uncoated scaffolds and scaffolds coated with organic/inorganic hybrids containing graphene offered the cultured cells an adequate surface for cell attachment, spreading and expression of extracellular matrix. The results showed that scaffolds coated with graphene are biocompatible and they can support cellular activity. The electrical conductivity introduced by the coating might have the potential to increase tissue growth when cell culture is carried out under an applied electric field.

  14. Synthesis and properties control of fluorinated organic-inorganic hybrid films

    NASA Astrophysics Data System (ADS)

    Yu, Qingjie; Xu, Jianming; Han, Yuanyuan

    2011-12-01

    Fluorinated organic-inorganic hybrid films were prepared by free-radical random copolymerization and sol-gel process through dodecafluoroheptyl methacrylate (DFMA), vinyltriethoxysilane (VTES), and tetramethoxysilane (TMOS). It was found that the prepared fluorinated organic-inorganic hybrid film was very hydrophobic and exhibits excellent water repellency. Hydrophobic fluorocarbon side chains were preferentially enriched to the outermost layer at the interface of coating film-air, and three layers probably exist in the coating films. The fluorinated hybrid films possessed fluorocarbon side chains orient toward the air originating from DFMA as the top layer, hydrocarbon backbone chain originating from vinyl polymerization as the middle layer, and silica network originating from the hydrolysis and condensation of siloxane as the bottom layer. It demonstrated that most of TMOS added might be arranged to the bottom layer of the fluorinated hybrid films, and had a slight impact on the enrichment of fluorocarbon side chains of the outermost layer. However, the useful properties of the fluorinated organic-inorganic hybrid films such as thickness and corrosion resistant can be significantly improved by the increase of TMOS content.

  15. Metal Nanoparticle-Catalyzed Reduction Using Borohydride in Aqueous Media: A Kinetic Analysis of the Surface Reaction by Microfluidic SERS.

    PubMed

    Xie, Wei; Grzeschik, Roland; Schlücker, Sebastian

    2016-10-24

    Hydrides are widely used in reduction reactions. In protic solvents, their hydrolysis generates molecular hydrogen as a second reducing agent. The competition between these two parallel reduction pathways has been overlooked so far since both typically yield the same product. We investigated the platinum-catalyzed reduction of 4-nitrothiophenol to 4-aminothiophenol in aqueous sodium borohydride solution as a prominent model reaction, by using label-free SERS monitoring in a microfluidic reactor. Kinetic analysis revealed a strong pH dependence. Surprisingly, only at pH>13 the reduction is driven exclusively by sodium borohydride. This study demonstrates the potential of microfluidics-based kinetic SERS monitoring of heterogeneous catalysis in colloidal suspension. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Surface chemistry for molecular layer deposition of organic and hybrid organic-inorganic polymers.

    PubMed

    George, Steven M; Yoon, Byunghoon; Dameron, Arrelaine A

    2009-04-21

    The fabrication of many devices in modern technology requires techniques for growing thin films. As devices miniaturize, manufacturers will need to control thin film growth at the atomic level. Because many devices have challenging morphologies, thin films must be able to coat conformally on structures with high aspect ratios. Techniques based on atomic layer deposition (ALD), a special type of chemical vapor deposition, allow for the growth of ultra-thin and conformal films of inorganic materials using sequential, self-limiting reactions. Molecular layer deposition (MLD) methods extend this strategy to include organic and hybrid organic-inorganic polymeric materials. In this Account, we provide an overview of the surface chemistry for the MLD of organic and hybrid organic-inorganic polymers and examine a variety of surface chemistry strategies for growing polymer thin films. Previously, surface chemistry for the MLD of organic polymers such as polyamides and polyimides has used two-step AB reaction cycles using homo-bifunctional reactants. However, these reagents can react twice and eliminate active sites on the growing polymer surface. To avoid this problem, we can employ alternative precursors for MLD based on hetero-bifunctional reactants and ring-opening reactions. We can also use surface activation or protected chemical functional groups. In addition, we can combine the reactants for ALD and MLD to grow hybrid organic-inorganic polymers that should display interesting properties. For example, using trimethylaluminum (TMA) and various diols as reactants, we can achieve the MLD of alucone organic-inorganic polymers. We can alter the chemical and physical properties of these organic-inorganic polymers by varying the organic constituent in the diol or blending the alucone MLD films with purely inorganic ALD films to build a nanocomposite or nanolaminate. The combination of ALD and MLD reactants enlarges the number of possible sequential self-limiting surface

  17. Fluorescence microscopy as an alternative to electron microscopy for microscale dispersion evaluation of organic-inorganic composites

    NASA Astrophysics Data System (ADS)

    Guan, Weijiang; Wang, Si; Lu, Chao; Tang, Ben Zhong

    2016-06-01

    Inorganic dispersion is of great importance for actual implementation of advanced properties of organic-inorganic composites. Currently, electron microscopy is the most conventional approach for observing dispersion of inorganic fillers from ultrathin sections of organic-inorganic composites at the nanoscale by professional technicians. However, direct visualization of macrodispersion of inorganic fillers in organic-inorganic composites using high-contrast fluorescent imaging method is hampered. Here we design and synthesize a unique fluorescent surfactant, which combines the properties of the aggregation-induced emission (AIE) and amphiphilicity, to image macrodispersion of montmorillonite and layered double hydroxide fillers in polymer matrix. The proposed fluorescence imaging provides a number of important advantages over electron microscope imaging, and opens a new avenue in the development of direct three-dimensional observation of inorganic filler macrodispersion in organic-inorganic composites.

  18. Fluorescence microscopy as an alternative to electron microscopy for microscale dispersion evaluation of organic-inorganic composites.

    PubMed

    Guan, Weijiang; Wang, Si; Lu, Chao; Tang, Ben Zhong

    2016-06-02

    Inorganic dispersion is of great importance for actual implementation of advanced properties of organic-inorganic composites. Currently, electron microscopy is the most conventional approach for observing dispersion of inorganic fillers from ultrathin sections of organic-inorganic composites at the nanoscale by professional technicians. However, direct visualization of macrodispersion of inorganic fillers in organic-inorganic composites using high-contrast fluorescent imaging method is hampered. Here we design and synthesize a unique fluorescent surfactant, which combines the properties of the aggregation-induced emission (AIE) and amphiphilicity, to image macrodispersion of montmorillonite and layered double hydroxide fillers in polymer matrix. The proposed fluorescence imaging provides a number of important advantages over electron microscope imaging, and opens a new avenue in the development of direct three-dimensional observation of inorganic filler macrodispersion in organic-inorganic composites.

  19. Broad-Band-Emissive Organic-Inorganic Hybrid Semiconducting Nanowires Based on an ABX3-Type Chain Compound.

    PubMed

    Wu, Zhenyue; Li, Lina; Ji, Chengmin; Lin, Guoming; Wang, Sasa; Shen, Yaoguo; Sun, Zhihua; Zhao, Sangen; Luo, Junhua

    2017-08-07

    Organic-inorganic hybrid lead halide (e.g., CH3NH3PbX3, where X = CI, Br, and I) nanowires (NWs) with remarkable electric and optical properties have recently garnered increasing attention, owing to their structural flexibility and tunability compared to inorganic semiconducting NWs. While most recently reported NWs are limited to methylammonium/formamidinium three-dimensional lead halide perovskites, it is urgent to develop new organic-inorganic hybrid semiconducting NWs. Here, broad-band-emissive single-crystal semiconductive NWs based on a new ABX3-type organic-inorganic chain hybrid, (2-methylpiperidine)lead tribromide, are reported. It is believed that this work will enrich the organic-inorganic hybrid semiconducting NWs and may provide potential applications for LED displaying.

  20. Electrochemical THz-SERS Observation of Thiol Monolayers on Au(111) and (100) Using Nanoparticle-assisted Gap-Mode Plasmon Excitation.

    PubMed

    Inagaki, Motoharu; Motobayashi, Kenta; Ikeda, Katsuyoshi

    2017-09-07

    Surface-enhanced Raman scattering (SERS) microscopy using nanoparticle-assisted gap-mode plasmon excitation, which enables us to observe an atomically defined planar metal surface, was combined with THz-Raman spectroscopy to observe ultra-low-frequency vibration modes under electrochemical conditions. This combination helps us to gain deeper insights into electrode/electrolyte interfaces via direct observation of extramolecular vibrations including information on intermolecular and substrate/molecule interactions. Electrochemical reductive desorption of benzenethiol derivatives from Au(111) and (100) was monitored to demonstrate the power of this spectroscopy. Structural differences of the monolayers between these surfaces were seen only in the extramolecular vibration modes such as a large-amplitude hinge-bending motion of the phenyl ring. On the Au(111), where hollow-site and bridge-site adsorption coexisted, the electrochemical reductive desorption was preferentially induced at the hollow sites.

  1. Aqueously Dispersed Silver Nanoparticle-Decorated Boron Nitride Nanosheets for Reusable, Thermal Oxidation-Resistant Surface Enhanced Raman Spectroscopy (SERS) Devices

    NASA Technical Reports Server (NTRS)

    Lin, Yi; Bunker, Christopher E.; Fernandos, K. A. Shiral; Connell, John W.

    2012-01-01

    The impurity-free aqueous dispersions of boron nitride nanosheets (BNNS) allowed the facile preparation of silver (Ag) nanoparticle-decorated BNNS by chemical reduction of an Ag salt with hydrazine in the presence of BNNS. The resultant Ag-BNNS nanohybrids remained dispersed in water, allowing convenient subsequent solution processing. By using substrate transfer techniques, Ag-BNNS nanohybrid thin film coatings on quartz substrates were prepared and evaluated as reusable surface enhanced Raman spectroscopy (SERS) sensors that were robust against repeated solvent washing. In addition, because of the unique thermal oxidation-resistant properties of the BNNS, the sensor devices may be readily recycled by short-duration high temperature air oxidation to remove residual analyte molecules in repeated runs. The limiting factor associated with the thermal oxidation recycling process was the Ostwald ripening effect of Ag nanostructures.

  2. Aqueously dispersed silver nanoparticle-decorated boron nitride nanosheets for reusable, thermal oxidation-resistant surface enhanced Raman spectroscopy (SERS) devices.

    PubMed

    Lin, Yi; Bunker, Christopher E; Fernando, K A Shiral; Connell, John W

    2012-02-01

    The impurity-free aqueous dispersions of boron nitride nanosheets (BNNS) allowed the facile preparation of silver (Ag) nanoparticle-decorated BNNS by chemical reduction of an Ag salt with hydrazine in the presence of BNNS. The resultant Ag-BNNS nanohybrids remained dispersed in water, allowing convenient subsequent solution processing. By using substrate transfer techniques, Ag-BNNS nanohybrid thin film coatings on quartz substrates were prepared and evaluated as reusable surface enhanced Raman spectroscopy (SERS) sensors that were robust against repeated solvent washing. In addition, because ofthe unique thermal oxidation-resistant properties of the BNNS, the sensor devices may be readily recycled by short-duration high temperature air oxidation to remove residual analyte molecules in repeated runs. The limiting factor associated with the thermal oxidation recycling process was the Ostwald ripening effect of Ag nanostructures.

  3. Aqueously Dispersed Silver Nanoparticle-Decorated Boron Nitride Nanosheets for Reusable, Thermal Oxidation-Resistant Surface Enhanced Raman Spectroscopy (SERS) Devices

    NASA Technical Reports Server (NTRS)

    Lin, Yi; Bunker, Christopher E.; Fernandos, K. A. Shiral; Connell, John W.

    2012-01-01

    The impurity-free aqueous dispersions of boron nitride nanosheets (BNNS) allowed the facile preparation of silver (Ag) nanoparticle-decorated BNNS by chemical reduction of an Ag salt with hydrazine in the presence of BNNS. The resultant Ag-BNNS nanohybrids remained dispersed in water, allowing convenient subsequent solution processing. By using substrate transfer techniques, Ag-BNNS nanohybrid thin film coatings on quartz substrates were prepared and evaluated as reusable surface enhanced Raman spectroscopy (SERS) sensors that were robust against repeated solvent washing. In addition, because of the unique thermal oxidation-resistant properties of the BNNS, the sensor devices may be readily recycled by short-duration high temperature air oxidation to remove residual analyte molecules in repeated runs. The limiting factor associated with the thermal oxidation recycling process was the Ostwald ripening effect of Ag nanostructures.

  4. Detection of trace melamine in raw materials used for protein pharmaceutical manufacturing using surface-enhanced Raman spectroscopy (SERS) with gold nanoparticles.

    PubMed

    Wen, Zai-Qing; Li, Guiyang; Ren, Da

    2011-05-01

    Melamine, a nitrogen-rich molecule, was found as an adulterant in pet foods in 2007 in North America and in milk products in 2008 in China. These scandalous abuses of melamine have alarmed the biopharmaceutical industry and the FDA and alerted them to potential adulteration and contamination of melamine in raw materials used to make protein therapeutics. Highly sensitive analytical methods are needed to screen melamine adulteration and contamination in raw materials. We conducted surface-enhanced Raman spectroscopy (SERS) experiments to test trace melamine spiked in three raw materials commonly used for protein pharmaceutical formulation and purification, including sucrose, urea, and arginine, with a portable Raman device and gold nanoparticles. The detection limit of 10 ppb in raw material dissolved in 30:70% water/acetonitrile is equivalent to 0.5 ppm in solid raw material. It has excellent linearity in the concentration range measured. The cross-validation regression coefficient R(2) and the standard error of prediction (SEP) are 0.960 and 7.18 ppb, respectively, in sucrose. The R(2) and SEP are 0.958 and 9.15 ppb in urea. It has a relatively lower R(2) = 0.630 and a SEP of 35.0 ppb in arginine, which could be due to the competitive adsorption of arginine molecules to the surfaces of gold nanoparticles. The detection of melamine using the SERS technique is rapid (within 3 minutes), convenient, and requires no extraction procedure, offering an alternative method for screening melamine in raw materials at biopharmaceutical manufacture sites.

  5. Facile fabrication of organic/inorganic nanotube heterojunction arrays for enhanced photoelectrochemical water splitting

    NASA Astrophysics Data System (ADS)

    Chen, Yingzhi; Li, Aoxiang; Yue, Xiaoqi; Wang, Lu-Ning; Huang, Zheng-Hong; Kang, Feiyu; Volinsky, Alex A.

    2016-07-01

    Organic/inorganic heterojunction photoanodes are appealing for making concurrent use of the highly photoactive organic semiconductors, and the efficient dielectric screening provided by their inorganic counterparts. In the present work, organic/inorganic nanotube heterojunction arrays composed of TiO2 nanotube arrays and a semiconducting N,N-(dicyclohexyl) perylene-3,4,9,10-tetracarboxylic diimide (PDi) layer were fabricated for photoelectrochemical water splitting. In this arrayed architecture, a PDi layer with a tunable thickness was coated on anodic TiO2 nanotube arrays by physical vapor deposition, which is advantageous for the formation of a uniform layer and an adequate interface contact between PDi and TiO2. The obtained PDi/TiO2 junction exhibited broadened visible light absorption, and an effective interface for enhanced photogenerated electron-hole separation, which is supported by the reduced charge transfer resistance and prolonged excitation lifetime via impedance spectroscopy analysis and fluorescence emission decay investigations. Consequently, such a heterojunction photoanode was photoresponsive to a wide visible light region of 400-600 nm, and thus demonstrated a highly enhanced photocurrent density at 1.23 V vs. a reversible hydrogen electrode. Additionally, the durability of such a photoanode can be guaranteed after long-time illumination because of the geometrical restraint imposed by the PDi aggregates. These results pave the way to discover new organic/inorganic assemblies for high-performance photoelectric applications and device integration.Organic/inorganic heterojunction photoanodes are appealing for making concurrent use of the highly photoactive organic semiconductors, and the efficient dielectric screening provided by their inorganic counterparts. In the present work, organic/inorganic nanotube heterojunction arrays composed of TiO2 nanotube arrays and a semiconducting N,N-(dicyclohexyl) perylene-3,4,9,10-tetracarboxylic diimide (PDi

  6. Modeling the Thermodynamics of Mixed Organic-Inorganic Aerosols to Predict Water Activities and Phase Equilibria

    NASA Astrophysics Data System (ADS)

    Zuend, A.; Marcolli, C.; Luo, B.; Peter, T.

    2008-12-01

    Tropospheric aerosol particles contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. Interactions between these substances in liquid mixtures lead to discrepancies from ideal thermodynamic behavior. While the thermodynamics of aqueous inorganic systems at atmospheric temperatures are well established, little is known about the physicochemistry of mixed organic-inorganic particles. Salting-out and salting-in effects result from organic-inorganic interactions and are used to improve industrial separation processes. In the atmosphere, they may influence the aerosol phases. Liquid-liquid phase separations into a mainly polar (aqueous) and a less polar organic phase may considerably influence the gas/particle partitioning of semi-volatile substances compared to a single phase estimation. Moreover, the phases present in the aerosol define the reaction medium for heterogeneous and multiphase chemistry occurring in aerosol particles. A correct description of these phases is needed when gas- or cloud-phase reaction schemes are adapted to aerosols. Non-ideal thermodynamic behavior in mixtures is usually described by an expression for the excess Gibbs energy. We present the group-contribution model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients), which explicitly accounts for molecular interactions between solution constituents, both organic and inorganic, to calculate activities, chemical potentials and the total Gibbs energy of mixed systems. This model allows to compute vapor-liquid (VLE), liquid-liquid (LLE) and solid-liquid (SLE) equilibria within one framework. Focusing on atmospheric applications we considered eight different cations, five anions and a wide range of alcohols/polyols as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are very well represented up to high ionic strength. We show that the semiempirical middle

  7. Nanoscale chemical tomography of buried organic-inorganic interfaces in the chiton tooth.

    PubMed

    Gordon, Lyle M; Joester, Derk

    2011-01-13

    Biological organisms possess an unparalleled ability to control the structure and properties of mineralized tissues. They are able, for example, to guide the formation of smoothly curving single crystals or tough, lightweight, self-repairing skeletal elements. In many biominerals, an organic matrix interacts with the mineral as it forms, controls its morphology and polymorph, and is occluded during mineralization. The remarkable functional properties of the resulting composites-such as outstanding fracture toughness and wear resistance-can be attributed to buried organic-inorganic interfaces at multiple hierarchical levels. Analysing and controlling such interfaces at the nanometre length scale is critical also in emerging organic electronic and photovoltaic hybrid materials. However, elucidating the structural and chemical complexity of buried organic-inorganic interfaces presents a challenge to state-of-the-art imaging techniques. Here we show that pulsed-laser atom-probe tomography reveals three-dimensional chemical maps of organic fibres with a diameter of 5-10 nm in the surrounding nano-crystalline magnetite (Fe(3)O(4)) mineral in the tooth of a marine mollusc, the chiton Chaetopleura apiculata. Remarkably, most fibres co-localize with either sodium or magnesium. Furthermore, clustering of these cations in the fibre indicates a structural level of hierarchy previously undetected. Our results demonstrate that in the chiton tooth, individual organic fibres have different chemical compositions, and therefore probably different functional roles in controlling fibre formation and matrix-mineral interactions. Atom-probe tomography is able to detect this chemical/structural heterogeneity by virtue of its high three-dimensional spatial resolution and sensitivity across the periodic table. We anticipate that the quantitative analysis and visualization of nanometre-scale interfaces by laser-pulsed atom-probe tomography will contribute greatly to our understanding not

  8. Label-free selective SERS detection of PCB-77 based on DNA aptamer modified SiO₂@Au core/shell nanoparticles.

    PubMed

    Lu, Yilin; Huang, Qing; Meng, Guowen; Wu, Lijun; Jingjing, Zhang

    2014-06-21

    A label-free approach to selective detection of 3,3',4,4'-tetrachlorobiphenyl (PCB77) using aptamer modified silica-Au/core-shell nanoparticles (denoted as SiO2@Au core/shell NPs) through surface enhanced Raman scattering (SERS) spectroscopy was proposed. The devised system consisted of SiO2@Au core/shell NPs fixed on the amino-silane functionalized glass slides with the PCB77-binding aptamers attached covalently to the gold surfaces through a thiol linker. The aptamers made of single-stranded DNA (ssDNA) oligomers with one end standing on the Au surface changed the conformation upon conjugation with PCB77, which correspondingly caused the spectral response of the ssDNA oligomers. The intensity ratio I(660 cm(-1))/I(736 cm(-1)) decreased with the amount of PCB77 added, which thus allowed us to measure trace amounts of PCB77 in a selective and quantitative way. This work therefore demonstrates that the design of aptamer-modified SiO2@Au core/shell NPs can be utilized for label-free SERS detection of persistent organic pollutants (POPs) in the environment.

  9. Synthesis of rGO-Ag nanoparticles for high-performance SERS and the adsorption geometry of 2-mercaptobenzimidazole on Ag surface

    NASA Astrophysics Data System (ADS)

    Zheng, H. L.; Yang, S. S.; Zhao, J.; Zhang, Z. C.

    2014-03-01

    The sliver nanoparticles (AgNPs) with diameters of 30˜50 nm were self-assembled onto the surfaces of reduced graphene oxide (rGO) sheets simply by mixing AgNO3 aqueous solution and GO dispersion via a synchronous reduction process. Structure and morphology of the rGO-AgNPs hybrids were well characterized. More significantly, the surface-enhanced Raman scattering (SERS) spectrum of 2-mercaptobenzimidazole (MBI) adsorbed on the solid rGO-AgNPs surface shown that the rGO-AgNPs system gives a very strong SERS intensity at in-plane vibrational modes in comparison to the out-of-plane vibrational modes. This large enhancement effect is most likely a result of charge-transfer (CT) mechanism. Based on the surface selection rules and the information provided by the highly enhanced in-plane vibrational modes, it can be found that MBI molecule was adsorbed on AgNPs surface as a thiol form via the sulphur and nitrogen atoms with a slightly tilted geometric conformation.

  10. Gravimetric chemical sensors based on silica-based mesoporous organic-inorganic hybrids.

    PubMed

    Xu, Jiaqiang; Zheng, Qi; Zhu, Yongheng; Lou, Huihui; Xiang, Qun; Cheng, Zhixuan

    2014-09-01

    Silica-based mesoporous organic-inorganic hybrid material modified quartz crystal microbalance (QCM) sensors have been examined for their ability to achieve highly sensitive and selective detection. Mesoporous silica SBA-15 serves as an inorganic host with large specific surface area, facilitating gas adsorption, and thus leads to highly sensitive response; while the presence of organic functional groups contributes to the greatly improved specific sensing property. In this work, we summarize our efforts in the rational design and synthesis of novel sensing materials for the detection of hazardous substances, including simulant nerve agent, organic vapor, and heavy metal ion, and develop high-performance QCM-based chemical sensors.

  11. Quantum confinement of zero-dimensional hybrid organic-inorganic polaritons at room temperature

    SciTech Connect

    Nguyen, H. S.; Lafosse, X.; Amo, A.; Bouchoule, S.; Bloch, J.; Abdel-Baki, K.; Lauret, J.-S.; Deleporte, E.

    2014-02-24

    We report on the quantum confinement of zero-dimensional polaritons in perovskite-based microcavity at room temperature. Photoluminescence of discrete polaritonic states is observed for polaritons localized in symmetric sphere-like defects which are spontaneously nucleated on the top dielectric Bragg mirror. The linewidth of these confined states is found much sharper (almost one order of magnitude) than that of photonic modes in the perovskite planar microcavity. Our results show the possibility to study organic-inorganic cavity polaritons in confined microstructure and suggest a fabrication method to realize integrated polaritonic devices operating at room temperature.

  12. Hydrolysis of oligosaccharides from distillers grains using organic-inorganic hybrid mesoporous silica catalysts.

    PubMed

    Bootsma, Jason A; Entorf, Matthew; Eder, Judd; Shanks, Brent H

    2008-08-01

    The use of propylsulfonic acid-functionalized mesoporous silica as a catalyst for the hydrolysis of oligosaccharides released by hydrothermal pretreatment of distiller's grains was examined in batch reactor studies. The effectiveness of the catalyst system for oligosaccharide hydrolysis was found to improve significantly with increased reaction temperature. This higher temperature operation allowed for more selective recovery of glucose, but was detrimental to arabinose recovery since significant degradation occurred. Xylose recovery efficiency improved with increasing temperature, but the higher temperature led to increased degradation. Using a model feed, solubilized proteins were found to deactivate the organic-inorganic hybrid catalyst, but a simple pretreatment with activated silica was found to alleviate the deactivation.

  13. Tightly bound indirect exciton in single-layer hybrid organic-inorganic perovskite semiconductor

    NASA Astrophysics Data System (ADS)

    Li, Jing; Liu, Tao; Liew, Timothy C. H.

    2017-10-01

    We theoretically study the direct and indirect excitons (IXs) in a single-layer hybrid organic-inorganic perovskite (HOIP) semiconductor. Due to the 2D nature, the single-layer HOIP supports the large binding energy of IXs and direct excitons over a wide range of applied electric fields, which exceed the thermal energy of room temperature. Moreover, the ground-state IX has a lower energy than that of direct exciton, which will extend the coherence and relaxation time of IXs. This is beneficial to optoelectronic applications and excitonic information processing devices of IXs.

  14. The field-dependent interface recombination velocity for organic-inorganic heterojunction

    NASA Astrophysics Data System (ADS)

    Szmytkowski, Jędrzej

    2016-10-01

    We have derived an analytical formula which describes the field-dependent interface recombination velocity for the boundary of two materials characterized by different permittivities. The interface recombination of charge carriers has been considered in the presence of image force Schottky barrier. We suggest that this effect may play an important role in the loss of current for organic-inorganic hybrid heterojunctions. It has been proved that the presented method is a generalization of the Scott-Malliaras model of surface recombination at the organic/metal interface. We also discuss that this model is intuitively similar but not analogous to the Langevin mechanism of bulk recombination.

  15. Optical and electronic properties of self-assembled nanoparticle-ligand metasurfaces

    NASA Astrophysics Data System (ADS)

    Fontana, Jake; Livenere, John; Caldwell, Joshua; Spillmann, Christopher; Naciri, Jawad; Rendell, Ronald; Ratna, Banahalli

    2013-03-01

    The optical and electronic properties of inorganic nanoparticles organized into two-dimensional lattices sensitively depend on the properties of the organic ligand shell coating the nanoparticles. We study the optical and electronic properties of these two-dimensional metasurfaces consisting of gold nanoparticles functionalized with ligands and self-assembled into macroscopic monolayers on non-templated substrates. Using these metasurfaces we demonstrate an average surface-enhanced Raman scattering (SERS) enhancement factor on the order of 108 for benzenethiol ligands and study the mechanisms that influence the enhancement. These metasurfaces may provide a platform for the development of low-power, low-cost next-generation chem/bio-sensors and new insights into the organic-inorganic interface at the nanoscale. This work was supported with funding provided from the Office of Naval Research

  16. Controlled-layer and large-area MoS2 films encapsulated Au nanoparticle hybrids for SERS.

    PubMed

    Li, Zhen; Jiang, Shouzhen; Huo, Yanyan; Liu, Mei; Yang, Cheng; Zhang, Chao; Liu, Xiaoyun; Sheng, Yingqing; Li, Chonghui; Man, Baoyuan

    2016-11-14

    In this work, a facile and effective method for controlled-layer and large-area MoS2 films encapsulated Au nanoparticle hybrids is developed. With accurate Ar plasma treatment time control, the large-area MoS2 layers can be obtained from monolayer to trilayer. The fabricated MoS2@Au NPs with higher surface area exhibit excellent Raman enhanced effect for aromatic organic molecules (rhodamine 6G and crystal violet) and achieve the best when the monolayer MoS2@AuNPs was obtained. The limit of detection is found to be as low as 1 × 10-10 M. The MoS2@AuNPs was characterized by SEM, EDS, AFM, Raman spectroscopy, UV-Vis, XRD and HRTEM.

  17. DNA origami based Au–Ag-core–shell nanoparticle dimers with single-molecule SERS sensitivity† †Electronic supplementary information (ESI) available: Additional information about materials and methods, designs of DNA origami templates, height profiles, additional SERS spectra, assignment of DNA bands, SEM images, additional AFM images, FDTD simulations, additional reference spectra for Cy3 and detailed description of EF estimation, simulated absorption and scattering spectra. See DOI: 10.1039/c5nr08674d Click here for additional data file.

    PubMed Central

    Prinz, J.; Heck, C.; Ellerik, L.; Merk, V.

    2016-01-01

    DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled. PMID:26892770

  18. Polymeric media comprising polybenzimidazoles N-substituted with organic-inorganic hybrid moiety

    DOEpatents

    Klaehn, John R [Idaho Falls, ID; Peterson, Eric S [Idaho Falls, ID; Wertsching, Alan K [Idaho Falls, ID; Orme, Christopher J [Shelley, ID; Luther, Thomas A [Idaho Falls, ID; Jones, Michael G [Pocatello, ID

    2009-12-15

    A PBI compound includes imidazole nitrogens at least a portion of which are substituted with an organic-inorganic hybrid moiety may be included in a separator medium. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2-- where R is selected from among methyl, phenyl, vinyl, and allyl. The separatory medium may exhibit an H.sub.2, Ar, N.sub.2, O.sub.2, CH.sub.3, or CO.sub.2 gas permeability greater than the gas permeability of a comparable separatory medium comprising the PBI compound without substitution. The separatory medium may further include an electronically conductive medium and/or ionically conductive medium. The separatory medium may be used as a membrane (semi-permeable, permeable, and non-permeable), a barrier, an ion exhcange media, a filter, a gas chromatography coating (such as stationary phase coating in affinity chromatography), etc.

  19. Exciton Binding Energy in Organic-Inorganic Tri-Halide Perovskites.

    PubMed

    Askar, Abdelrahman M; Shankar, Karthik

    2016-06-01

    The recent dramatic increase in the power conversion efficiencies of organic-inorganic tri-halide perovskite solar cells has triggered intense research worldwide and created a paradigm shift in the photovoltaics field. It is crucial to develop a solid understanding of the photophysical processes underlying solar cell operation in order to both further improve the photovoltaic performance of perovskite solar cells as well as to exploit the broader optoelectronic applications of the tri-halide perovskites. In this short review, we summarize the main research findings about the binding energy of excitons in tri-halide perovskite materials and find that a value in the range of 2-22 meV at room temperature would be a safe estimate. Spontaneous free carrier generation is the dominant process taking place directly after photoexcitation in organic-inorganic tri-halide perovskites at room temperature, which eliminates the exciton diffusion bottleneck present in organic solar cells and constitutes a major contributing factor to the high photovoltaic performance of this material.

  20. Modeling the surface tension of complex, reactive organic-inorganic mixtures

    NASA Astrophysics Data System (ADS)

    Schwier, A. N.; Viglione, G. A.; Li, Z.; McNeill, V. F.

    2013-01-01

    Atmospheric aerosols can contain thousands of organic compounds which impact aerosol surface tension, affecting aerosol properties such as cloud condensation nuclei (CCN) ability. We present new experimental data for the surface tension of complex, reactive organic-inorganic aqueous mixtures mimicking tropospheric aerosols. Each solution contained 2-6 organic compounds, including methylglyoxal, glyoxal, formaldehyde, acetaldehyde, oxalic acid, succinic acid, leucine, alanine, glycine, and serine, with and without ammonium sulfate. We test two surface tension models and find that most reactive, complex, aqueous organic mixtures which do not contain salt are well-described by a weighted Szyszkowski-Langmuir (S-L) model which was first presented by Henning et al. (2005). Two approaches for modeling the effects of salt were tested: (1) the Tuckermann approach (an extension of the Henning model with an additional explicit salt term), and (2) a new implicit method proposed here which employs experimental surface tension data obtained for each organic species in the presence of salt used with the Henning model. We recommend the use of method (2) for surface tension modeling because the Henning model (using data obtained from organic-inorganic systems) and Tuckermann approach provide similar modeling fits and goodness of fit (χ2) values, yet the Henning model is a simpler and more physical approach to modeling the effects of salt, requiring less empirically determined parameters.

  1. Modeling the surface tension of complex, reactive organic-inorganic mixtures

    NASA Astrophysics Data System (ADS)

    Schwier, A. N.; Viglione, G. A.; Li, Z.; McNeill, V. Faye

    2013-11-01

    Atmospheric aerosols can contain thousands of organic compounds which impact aerosol surface tension, affecting aerosol properties such as heterogeneous reactivity, ice nucleation, and cloud droplet formation. We present new experimental data for the surface tension of complex, reactive organic-inorganic aqueous mixtures mimicking tropospheric aerosols. Each solution contained 2-6 organic compounds, including methylglyoxal, glyoxal, formaldehyde, acetaldehyde, oxalic acid, succinic acid, leucine, alanine, glycine, and serine, with and without ammonium sulfate. We test two semi-empirical surface tension models and find that most reactive, complex, aqueous organic mixtures which do not contain salt are well described by a weighted Szyszkowski-Langmuir (S-L) model which was first presented by Henning et al. (2005). Two approaches for modeling the effects of salt were tested: (1) the Tuckermann approach (an extension of the Henning model with an additional explicit salt term), and (2) a new implicit method proposed here which employs experimental surface tension data obtained for each organic species in the presence of salt used with the Henning model. We recommend the use of method (2) for surface tension modeling of aerosol systems because the Henning model (using data obtained from organic-inorganic systems) and Tuckermann approach provide similar modeling results and goodness-of-fit (χ2) values, yet the Henning model is a simpler and more physical approach to modeling the effects of salt, requiring less empirically determined parameters.

  2. Controllable lasing performance in solution-processed organic-inorganic hybrid perovskites.

    PubMed

    Kao, Tsung Sheng; Chou, Yu-Hsun; Hong, Kuo-Bin; Huang, Jiong-Fu; Chou, Chun-Hsien; Kuo, Hao-Chung; Chen, Fang-Chung; Lu, Tien-Chang

    2016-11-03

    Solution-processed organic-inorganic perovskites are fascinating due to their remarkable photo-conversion efficiency and great potential in the cost-effective, versatile and large-scale manufacturing of optoelectronic devices. In this paper, we demonstrate that the perovskite nanocrystal sizes can be simply controlled by manipulating the precursor solution concentrations in a two-step sequential deposition process, thus achieving the feasible tunability of excitonic properties and lasing performance in hybrid metal-halide perovskites. The lasing threshold is at around 230 μJ cm(-2) in this solution-processed organic-inorganic lead-halide material, which is comparable to the colloidal quantum dot lasers. The efficient stimulated emission originates from the multiple random scattering provided by the micro-meter scale rugged morphology and polycrystalline grain boundaries. Thus the excitonic properties in perovskites exhibit high correlation with the formed morphology of the perovskite nanocrystals. Compared to the conventional lasers normally serving as a coherent light source, the perovskite random lasers are promising in making low-cost thin-film lasing devices for flexible and speckle-free imaging applications.

  3. Microscopic origin of entropy-driven polymorphism in hybrid organic-inorganic perovskite materials

    NASA Astrophysics Data System (ADS)

    Butler, Keith T.; Svane, Katrine; Kieslich, Gregor; Cheetham, Anthony K.; Walsh, Aron

    2016-11-01

    Entropy is a critical, but often overlooked, factor in determining the relative stabilities of crystal phases. The importance of entropy is most pronounced in softer materials, where small changes in free energy can drive phase transitions, which has recently been demonstrated in the case of organic-inorganic hybrid-formate perovskites. In this Rapid Communication we demonstrate the interplay between composition and crystal structure that is responsible for the particularly pronounced role of entropy in determining polymorphism in hybrid organic-inorganic materials. Using ab initio based lattice dynamics, we probe the origins and effects of vibrational entropy of four archetype perovskite (A B X3 ) structures. We consider an inorganic material (SrTiO3), an A -site hybrid-halide material (CH3NH3) PbI3 , a X -site hybrid material KSr (BH4)3 , and a mixed A - and X -site hybrid-formate material (N2H5) Zn (HCO2)3 , comparing the differences in entropy between two common polymorphs. The results demonstrate the importance of low-frequency intermolecular modes in determining the phase stability in these materials. The understanding gained allows us to propose a general principle for the relative stability of different polymorphs of hybrid materials as temperature is increased.

  4. Fluorescent and cross-linked organic-inorganic hybrid nanoshells for monitoring drug delivery.

    PubMed

    Sun, Lijuan; Liu, Tianhui; Li, Hua; Yang, Liang; Meng, Lingjie; Lu, Qinghua; Long, Jiangang

    2015-03-04

    Functionalized and monodisperse nanoshells have attracted significant attention owing to their well-defined structure, unique properties, and wide range of potential applications. Here, the synthesis of cross-linked organic-inorganic hybrid nanoshells with strong fluorescence properties was reported via a facile precipitation polymerization of hexachlorocyclotriphosphazene (HCCP) and fluorescein on silica particles used as templates. The resulting poly(cyclotriphosphazene-co-fluorescein) (PCTPF) nanoshells were firm cross-linked shells with ∼2.2 nm mesopores that facilitated the transport of drug molecules. The fluorescent nanoshells also exhibited excellent water dispersibility and biocompatibility; thus, they can be considered as ideal drug vehicles with high doxorubicin storage capacity (26.2 wt %) and excellent sustained release (up to 14 days). Compared to doxorubicin (DOX) alone, the PCTPF nanoshells more efficiently delivered DOX into and killed cancer cells. Moreover, the PCTPF nanoshells also exhibited remarkable fluorescent emission properties and improved photobleaching stability in both suspension and solid state owing to the covalent immobilization of fluorescein in the highly cross-linked organic-inorganic hybrids. The exceptional fluorescent properties enabled the release of DOX as well as the distribution of nanoshells and DOX to be monitored.

  5. Solution-processible organic-inorganic hybrid bipolar field-effect transistors

    NASA Astrophysics Data System (ADS)

    Chae, Gil Jo; Kim, Kang Dae; Cho, Shinuk; Walker, Bright; Seo, Jung Hwa

    2016-04-01

    Organic-inorganic hybrid bipolar field-effect transistors (HBFETs) comprising a layer of p-type organic poly(3-hexylthiophene) (P3HT) separated from a parallel layer of n-type inorganic zinc oxide (ZnO) were demonstrated by solution processing. In order to achieve balanced hole and electron mobilities, we initially optimized the hole-transporting P3HT channel by the addition of the polar non-solvent acetonitrile (AN) to P3HT solutions in chloroform, which induced a selfassembled nano-fibril morphology and an enhancement of hole mobilities. For the electron channel, a wet-chemically-prepared ZnO layer was optimized by thermal annealing. Unipolar P3HT FET with 5% AN exhibited the highest hole mobility of 7.20 × 10-2 cm2V-1s-1 while the highest electron mobility (3.64 × 10-2 cm2V-1s-1) was observed in unipolar ZnO FETs annealed at 200°C. The organic-inorganic HBFETs consisting of the P3HT layer with 5% AN and ZnO annealed at 200°C exhibited well-balanced hole and electron mobilities of 1.94 × 10-2 cm2V-1s-1 and 1.98 × 10-2 cm2V-1s-1, respectively.

  6. Efficient organic-inorganic hybrid Schottky solar cell: The role of built-in potential

    NASA Astrophysics Data System (ADS)

    Zhu, Yawen; Song, Tao; Zhang, Fute; Lee, Shuit-Tong; Sun, Baoquan

    2013-03-01

    The organic-inorganic hybrid Schottky solar cells based on solution processed poly(3,4-ethlenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in combination with silicon offer the merits of simple fabrication process and potential low cost. Here, we demonstrate that the work function (WF) of PEDOT:PSS films plays a critical role on the electronic output characteristics of the device. The WF of PEDOT:PSS is tuned by adding an aqueous solution of perfluorinated ionomer (PFI) due to its high electron affinity, which is compatible to fabricate the hybrid Si/PEDOT:PSS device. With an addition of 4% (weight) PFI into PEDOT:PSS, the device achieves a fill factor (FF) as high as 0.70 without sacrifice of open-circuit voltage and short-circuit current density, which improves 20% in comparison with the pristine PEDOT:PSS (0.58). The detailed electrical output measurements reveal that the high FF is ascribed to the enhanced built-in potential as well as suppression of charge recombination at organic-inorganic interface.

  7. Electrochromic conductive polymer fuses for hybrid organic/inorganic semiconductor memories

    NASA Astrophysics Data System (ADS)

    Möller, Sven; Forrest, Stephen R.; Perlov, Craig; Jackson, Warren; Taussig, Carl

    2003-12-01

    We demonstrate a nonvolatile, write-once-read-many-times (WORM) memory device employing a hybrid organic/inorganic semiconductor architecture consisting of thin film p-i-n silicon diode on a stainless steel substrate integrated in series with a conductive polymer fuse. The nonlinearity of the silicon diodes enables a passive matrix memory architecture, while the conductive polyethylenedioxythiophene:polystyrene sulfonic acid polymer serves as a reliable switch with fuse-like behavior for data storage. The polymer can be switched at ˜2 μs, resulting in a permanent decrease of conductivity of the memory pixel by up to a factor of 103. The switching mechanism is primarily due to a current and thermally dependent redox reaction in the polymer, limited by the double injection of both holes and electrons. The switched device performance does not degrade after many thousand read cycles in ambient at room temperature. Our results suggest that low cost, organic/inorganic WORM memories are feasible for light weight, high density, robust, and fast archival storage applications.

  8. Stable hybrid organic/inorganic photocathodes for hydrogen evolution with amorphous WO3 hole selective contacts.

    PubMed

    Mezzetti, Alessandro; Fumagalli, Francesco; Alfano, Antonio; Iadicicco, Daniele; Antognazza, Maria Rosa; di Fonzo, Fabio

    2017-03-08

    Photoelectrochemical H2 production through hybrid organic/inorganic interfaces exploits the capability of polymeric absorbers to drive photo-induced electron transfer to an electrocatalyst in a water environment. Photoelectrode architectures based on solution-processed organic semiconductors are now emerging as low-cost alternatives to crystalline inorganic semiconductors based on Si, oxides and III-V alloys. In this work, we demonstrate that the stability of a hybrid organic/inorganic photocathode, employing a P3HT:PCBM blend as photoactive material, can be considerably improved by introducing an electrochemically stable WO3 hole selective layer, paired with a TiO2 electron selective layer. This hybrid photoelectrode exhibits a photocurrent of 2.48 mA cm(-2) at 0 VRHE, +0.56 VRHE onset potential and a state-of the art operational activity of more than 10 hours. This work gives the perspective that photoelectrodes based on organic semiconductors, coupled with proper inorganic selective contacts, represent a sound new option for the efficient and durable photoelectrochemical conversion of solar energy into fuels.

  9. New organic-inorganic hybrid material based on functional cellulose nanowhisker, polypseudorotaxane and Au nanorods.

    PubMed

    Garavand, Ali; Dadkhah Tehrani, Abbas

    2016-11-05

    Organic-inorganic functional hybrid materials play a major role in the development of advanced functional materials and recently have gained growing interest of the worldwide community. In this context, new hybrid organic-inorganic gel consisting of cellulose nanowhisker xanthate (CNWX) and S-H functionalized polypseudorotaxane (PPR) as organic parts of gel and gold nanorods (GNRs) as inorganic cross-linking agent were prepared. Firstly, thiolated α-cyclodextrin (α-CD-SH) was threaded onto poly-(ethylene glycol) bis (mercaptoethanoate ester) (PEG-SH) to give polypseudorotaxane (PPR) and then it reacted with GNRs in the presence of CNWX to give the new hybrid gel material. The new synthesized gel and its components characterized by spectroscopic measurement methods such as FT-IR, UV-vis and NMR spectroscopy. Interestingly, hybrid gel showed new polygonal plate like morphology with 45-60nm thickness and 400-600nm width. The obtained gel may have potential application in many fields especially in biomedical applications.

  10. Particle size distributions and organic-inorganic compositions of suspended particulate matters around the Bohai Strait

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Bian, Changwei; Bi, Rong; Jiang, Wensheng; Zhang, Hua; Zhang, Xueqing

    2017-02-01

    Laser in situ scattering and transmissometry (LISST) significantly improves our ability to assess particle size distribution (PSD) in seawater, while wide-ranging measurements of the organic-inorganic compositions of suspended particulate matters (SPM) are still difficult by using traditional methods such as microscopy. In this study, PSD properties and SPM compositions around the Bohai Strait (China) were investigated based on the measurements by LISST in combination with hydro-biological parameters collected from a field survey in summer 2014. Four typical PSD shapes were found in the region, namely right-peak, left-peak, double-peak and negative-skew shapes. The double-peak and negative-skew shapes may interconvert into each other along with strong hydrodynamic variation. In the upper layer of the Bohai Sea, organic particles were in the majority, with inorganic particles rarely observed. In the bottom layer, SPM were the mixture of organic and inorganic matters. LISST provided valuable baseline information on size-resolved organic-inorganic compositions of SPM: the size of organic particles mainly ranged from 4 to 20 μm and 40 to 100 μm, while most SPM ranging from 20 to 40 μm were composed of inorganic sediment.

  11. Preparation, characterization and application of organic-inorganic hybrid caffeine imprinted monolith.

    PubMed

    Liu, Xiaofang; Sun, Na; Zhu, Quanfei; Wu, Mei; Ye, Yong; Chen, Huaixia

    2013-08-23

    The present work aims to synthesize an organic-inorganic hybrid caffeine imprinted monolith using one-step method. The synthesis conditions such as the type of inorganic precursor and porogenic solvent, the molar ratios of the monomer and cross-linker, the volume ratio of the inorganic alcoholysate and organic part were optimized. The morphology of the monolith was studied by scanning electron microscopy and Fourier transform infrared spectra. The imprinted factor of the monolith for caffeine reached 3.02. A simple, rapid and sensitive method for the determination of caffeine in children's milk using the organic-inorganic hybrid caffeine imprinted polymer monolith microextraction combined with high-performance liquid chromatography-photodiodes array detector was developed. Several parameters affecting the sample pretreatment were investigated, including the type, flow rate and volume of eluent, the flow rate and volume of sample solution. The assay exhibited a linear dynamic range of 8-500μgL(-1) with the correlation coefficient above 0.9987. Lower limits of detection (LOD, at S/N=3) and quantification (LOQ, at S/N=10) in children's milk samples were 2.7 and 8μgL(-1). Recoveries of caffeine from spiked children's milk ranged from 85 to 104% with relative standard deviations of less than 8.9%.

  12. Bioadhesive film formed from a novel organic-inorganic hybrid gel for transdermal drug delivery system.

    PubMed

    Guo, Ruiwei; Du, Xiaoyan; Zhang, Rui; Deng, Liandong; Dong, Anjie; Zhang, Jianhua

    2011-11-01

    A novel organic-inorganic hybrid film-forming agent for TDDS was developed by a modified poly(vinyl alcohol) (PVA) gel using γ-(glycidyloxypropyl)trimethoxysilane (GPTMS) as an inorganic-modifying agent, poly(N-vinyl pyrrolidone) (PVP) as a tackifier and glycerol (GLY) as a plasticizer. The prepared gels can be applied to the skin by a coating method and in situ form very thin and transparent films with good performance, comfortable feel and cosmetic attractiveness. The key properties of the bioadhesive films produced from the hybrid gels were investigated and the results showed that the incorporation of appropriate GPTMS (GPTMS/(PVA+GPTMS) in the range of 20-30%) into the PVA matrix not only can significantly enhance mechanical strength and skin adhesion properties of the resultant film, but also can decrease the crystalline regions of PVA and hence facilitate the diffusion of water vapor and drug. Furthermore, the investigations into in vivo skin irritation suggested the films caused non-irritation to skin after topical application for 120 h. In conclusion, the bioadhesive films formed from organic-inorganic hybrid gels possessed very good qualities for application on the skin and may provide a promising formulation for TDDS, especially when the patient acceptability from an aesthetic perspective of the dosage form is a prime consideration. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Giant Rashba Splitting in CH3NH3PbBr3 Organic-Inorganic Perovskite

    NASA Astrophysics Data System (ADS)

    Niesner, Daniel; Wilhelm, Max; Levchuk, Ievgen; Osvet, Andres; Shrestha, Shreetu; Batentschuk, Miroslaw; Brabec, Christoph; Fauster, Thomas

    2016-09-01

    As they combine decent mobilities with extremely long carrier lifetimes, organic-inorganic perovskites open a whole new field in optoelectronics. Measurements of their underlying electronic structure, however, are still lacking. Using angle-resolved photoelectron spectroscopy, we measure the valence band dispersion of single-crystal CH3NH3PbBr3. The dispersion of the highest energy band is extracted applying a modified leading edge method, which accounts for the particular density of states of organic-inorganic perovskites. The surface Brillouin zone is consistent with bulk-terminated surfaces both in the low-temperature orthorhombic and the high-temperature cubic phase. In the low-temperature phase, we find a ring-shaped valence band maximum with a radius of 0.043 Å-1 , centered around a 0.16 eV deep local minimum in the dispersion of the valence band at the high-symmetry point. Intense circular dichroism is observed. This dispersion is the result of strong spin-orbit coupling. Spin-orbit coupling is also present in the room-temperature phase. The coupling strength is one of the largest ones reported so far.

  14. Self-assembly of ferromagnetic organic-inorganic perovskite-like films.

    PubMed

    Akhtar, Naureen; Polyakov, Alexey O; Aqeel, Aisha; Gordiichuk, Pavlo; Blake, Graeme R; Baas, Jacob; Amenitsch, Heinz; Herrmann, Andreas; Rudolf, Petra; Palstra, Thomas T M

    2014-12-10

    Perovskite-based organic-inorganic hybrids hold great potential as active layers in electronics or optoelectronics or as components of biosensors. However, many of these applications require thin films grown with good control over structure and thickness--a major challenge that needs to be addressed. The work presented here is an effort towards this goal and concerns the layer-by-layer deposition at ambient conditions of ferromagnetic organic-inorganic hybrids consisting of alternating CuCl4-octahedra and organic layers. The Langmuir-Blodgett technique used to assemble these structures provides intrinsic control over the molecular organization and film thickness down to the molecular level. Magnetic characterization reveals that the coercive field for these thin films is larger than that for solution-grown layered bulk crystals. The strategy presented here suggests a promising cost effective route to facilitate the excellently controlled growth of sophisticated materials on a wide variety of substrates that have properties relevant for the high density storage media and spintronic devices.

  15. Ag-Incorporated Organic-Inorganic Perovskite Films and Planar Heterojunction Solar Cells.

    PubMed

    Chen, Qi; Chen, Lei; Ye, Fengye; Zhao, Ting; Tang, Feng; Rajagopal, Adharsh; Jiang, Zheng; Jiang, Shenlong; Jen, Alex K-Y; Xie, Yi; Cai, Jinhua; Chen, Liwei

    2017-04-06

    Controlled doping for adjustable material polarity and charge carrier concentration is the basis of semiconductor materials and devices, and it is much more difficult to achieve in ionic semiconductors (e.g., ZnO and GaN) than in covalent semiconductors (e.g., Si and Ge), due to the high intrinsic defect density in ionic semiconductors. The organic-inorganic perovskite material, which is frenetically being researched for applications in solar cells and beyond, is also an ionic semiconductor. Here we present the Ag-incorporated organic-inorganic perovskite films and planar heterojunction solar cells. Partial substitution of Pb(2+) by Ag(+) leads to improved film morphology, crystallinity, and carrier dynamics as well as shifted Fermi level and reduced electron concentration. Consequently, in planar heterojunction photovoltaic devices with inverted stacking structure, Ag incorporation results in an enhancement of the power conversion efficiency from 16.0% to 18.4% in MAPbI3 based devices and from 11.2% to 15.4% in MAPbI3-xClx based devices. Our work implies that Ag incorporation is a feasible route to adjust carrier concentrations in solution-processed perovskite materials in spite of the high concentration of intrinsic defects.

  16. Self-coated interfacial layer at organic/inorganic phase for temporally controlling dual-drug delivery from electrospun fibers.

    PubMed

    Zhao, Xin; Zhao, Jingwen; Lin, Zhi Yuan William; Pan, Guoqing; Zhu, Yueqi; Cheng, Yingsheng; Cui, Wenguo

    2015-06-01

    Implantable tissue engineering scaffolds with temporally programmable multi-drug release are recognized as promising tools to improve therapeutic effects. A good example would be one that exhibits initial anti-inflammatory and long-term anti-tumor activities after tumor resection. In this study, a new strategy for self-coated interfacial layer on drug-loaded mesoporous silica nanoparticles (MSNs) based on mussel-mimetic catecholamine polymer (polydopamine, PDA) layer was developed between inorganic and organic matrix for controlling drug release. When the interface PDA coated MSNs were encapsulated in electrospun poly(L-lactide) (PLLA) fibers, the release rates of drugs located inside/outside the interfacial layer could be finely controlled, with short-term release of anti-inflammation ibuprofen (IBU) for 30 days in absence of interfacial interactions and sustained long-term release of doxorubicin (DOX) for 90 days in presence of interfacial interactions to inhibit potential tumor recurrence. The DOX@MSN-PDA/IBU/PLLA hybrid fibrous scaffolds were further found to inhibit proliferation of inflammatory macrophages and cancerous HeLa cells, while supporting the normal stromal fibroblast adhesion and proliferation at different release stages. These results have suggested that the interfacial obstruction layer at the organic/inorganic phase was able to control the release of drugs inside (slow)/outside (rapid) the interfacial layer in a programmable manner. We believe such interface polymer strategy will find applications in where temporally controlled multi-drug delivery is needed. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. The interaction between hybrid organic-inorganic halide perovskite and selective contacts in perovskite solar cells: an infrared spectroscopy study.

    PubMed

    Idígoras, J; Todinova, A; Sánchez-Valencia, J R; Barranco, A; Borrás, A; Anta, J A

    2016-05-11

    The interaction of hybrid organic-inorganic halide perovskite and selective contacts is crucial to get efficient, stable and hysteresis-free perovskite-based solar cells. In this report, we analyze the vibrational properties of methylammonium lead halide perovskites deposited on different substrates by infrared absorption (IR) measurements (4000-500 cm(-1)). The materials employed as substrates are not only characterized by different chemical natures (TiO2, ZnO and Al2O3), but also by different morphologies. For all of them, we have investigated the influence of these substrate properties on perovskite formation and its degradation by humidity. The effect of selective-hole contact (Spiro-OmeTad and P3HT) layers on the degradation rate by moisture has also been studied. Our IR results reveal the existence of a strong interaction between perovskite and all ZnO materials considered, evidenced by a shift of the peaks related to the N-H vibrational modes. The interaction even induces a morphological change in ZnO nanoparticles after perovskite deposition, pointing to an acid-base reaction that takes place through the NH3(+) groups of the methylammonium cation. Our IR and X-ray diffraction results also indicate that this specific interaction favors perovskite decomposition and PbI2 formation for ZnO/perovskite films subjected to humid conditions. Although no interaction is observed for TiO2, Al2O3, and the hole selective contact, the morphology and chemical nature of both contacts appear to play an important role in the rate of degradation upon exposure to moisture.

  18. Thermodynamic Modeling of Organic-Inorganic Aerosols with the Group-Contribution Model AIOMFAC

    NASA Astrophysics Data System (ADS)

    Zuend, A.; Marcolli, C.; Luo, B. P.; Peter, T.

    2009-04-01

    Liquid aerosol particles are - from a physicochemical viewpoint - mixtures of inorganic salts, acids, water and a large variety of organic compounds (Rogge et al., 1993; Zhang et al., 2007). Molecular interactions between these aerosol components lead to deviations from ideal thermodynamic behavior. Strong non-ideality between organics and dissolved ions may influence the aerosol phases at equilibrium by means of liquid-liquid phase separations into a mainly polar (aqueous) and a less polar (organic) phase. A number of activity models exists to successfully describe the thermodynamic equilibrium of aqueous electrolyte solutions. However, the large number of different, often multi-functional, organic compounds in mixed organic-inorganic particles is a challenging problem for the development of thermodynamic models. The group-contribution concept as introduced in the UNIFAC model by Fredenslund et al. (1975), is a practical method to handle this difficulty and to add a certain predictability for unknown organic substances. We present the group-contribution model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients), which explicitly accounts for molecular interactions between solution constituents, both organic and inorganic, to calculate activities, chemical potentials and the total Gibbs energy of mixed systems (Zuend et al., 2008). This model enables the computation of vapor-liquid (VLE), liquid-liquid (LLE) and solid-liquid (SLE) equilibria within one framework. Focusing on atmospheric applications we considered eight different cations, five anions and a wide range of alcohols/polyols as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are very well represented up to high ionic strength. We show that the semi-empirical middle-range parametrization of direct organic-inorganic interactions in alcohol-water-salt solutions enables accurate computations of vapor-liquid and liquid

  19. Fabrication of nanoporous arrays from photosensitive organic-inorganic hybrid materials by using an UV soft nanoimprint technique.

    PubMed

    Zhang, Xuehua; Que, Wenxiu; Hu, Jiaxing; Chen, Jin; Zhang, Jin; Liu, Weiguo

    2013-02-01

    A honeycomb-like regular nanoporous pattern built in the photosensitive organic-inorganic hybrid film was fabricated by an UV soft nanoimprint technique. Polydimethylsiloxane (PDMS) soft mold was firstly replicated from an anodic aluminum oxide (AAO) template obtained by using a two-step anodization method. Scanning electron microscopy images show that the AAO template has a regular honeycomb-like nanoporous structure, while the PDMS soft mold has a relief structure of nanopillar arrays. Photosensitive TiO2-contained organic-inorganic hybrid films, which were prepared by combining a low temperature sol-gel process with a spin-coating technique, were used as the imprinted layer. Thus, a honeycomb-like regular nanoporous pattern built in the hybrid film can be easily obtained by imprinting the PDMS soft mold into the photosensitive hybrid film under an UV-irradiation. The as-fabricated organic-inorganic regular nonporous arrays have potential applications in two-dimensional photonic crystal.

  20. Highly Efficient Red-Light Emission in An Organic-Inorganic Hybrid Ferroelectric: (Pyrrolidinium)MnCl₃.

    PubMed

    Zhang, Yi; Liao, Wei-Qiang; Fu, Da-Wei; Ye, Heng-Yun; Chen, Zhong-Ning; Xiong, Ren-Gen

    2015-04-22

    Luminescence of ferroelectric materials is one important property for technological applications, such as low-energy electron excitation. However, the vast majority of doped inorganic ferroelectric materials have low luminescent efficiency. The past decade has envisaged much progress in the design of both ferroelectric and luminescent organic-inorganic hybrid complexes for optoelectronic applications. The combination of ferroelectricity and luminescence within organic-inorganic hybrids would lead to a new type of luminescent ferroelectric multifunctional materials. We herein report a hybrid molecular ferroelectric, (pyrrolidinium)MnCl3, which exhibits excellent ferroelectricity with a saturation polarization of 5.5 μC/cm(2) as well as intense red luminescence with high quantum yield of 56% under a UV excitation. This finding may extend the application of organic-inorganic hybrid compounds to the field of ferroelectric luminescence and/or multifunctional devices.

  1. Ultrafast pulse generation from erbium-doped fiber laser modulated by hybrid organic-inorganic halide perovskites

    NASA Astrophysics Data System (ADS)

    Jiang, Guobao; Miao, Lili; Yi, Jun; Huang, Bin; Peng, Wei; Zou, Yanhong; Huang, Huihui; Hu, Wei; Zhao, Chujun; Wen, Shuangchun

    2017-04-01

    We report the nonlinear optical responses of organic-inorganic halide perovskite CH3NH3PbI3 and its application in ultrafast pulse generation from an erbium-doped fiber laser in the optical communication band. By adopting the Z-scan technique, the third-order nonlinear optical responses of the organic-inorganic halide perovskites have been characterized. An ultrafast optical pulse with a pulse width of 661 fs centered at a wavelength of 1555 nm has been delivered via the nonlinear optical material introduced into the fiber laser cavity. Our experimental results confirm that the organic-inorganic halide perovskite possesses obvious third-order nonlinear optical responses in the C-band window and manifests its application potential in nonlinear optoelectronic devices.

  2. Submicron patterns obtained by thermal-induced reconstruction of self-assembled monolayer of Ag nanoparticles and their application in SERS

    NASA Astrophysics Data System (ADS)

    Ruan, Weidong; Zhou, Tieli; Cui, Yinqiu; Dong, Yujie; Liu, Zhuo; Dong, Fengxia; Wang, Haiyang; Luan, Xintong; Wang, Xu; Song, Wei; Zhao, Bing

    2014-08-01

    The layer-by-layer (LbL) self-assembly technique was employed for the deposition of poly(diallyldimethylammonium chloride) (PDDA) and triangular Ag nanoplates on glass substrates. A thermal-induced reconstruction of these polyelectrolyte-linked nanoparticle (NP) films was presented. Before the reconstruction, triangular Ag nanoplates were distributed uniformly on the surface with an average interval of 50 ± 15 nm. After the reconstruction, the triangular Ag nanoplates accumulated into discrete stacks with an average interval of 90 ± 25 nm. The temperature-dependent experiments were done and the optimal temperature for the formation of the reconstructed patterns was 120 °C. The possible mechanism of the NP movement and stacking was analyzed. Under the experimental conditions, a hydrophobic environment was formed because of the vacuum and heating. As a result the polyelectrolyte-linked Ag NPs preferred to congregate due to the lowered surface energy. Finally the submicron patterns were formed. The ultraviolet-visible (UV-vis) absorption and surface-enhanced Raman scattering (SERS) properties of the films before and after the reconstruction was investigated. The reconstructed films with submicron patterns had better SERS enhancement ability, which was 1300 times to the original films. The reconstruction method of the monolayer films showed great potential in the surface design and related applications. AFM images were obtained to clarify the three dimensional structures of the reconstructed films obtained at 120 °C. As shown in Fig. 2, the Ag NP stacks had an average diameter of 1.0 ± 0.2 μm and an average height of 170 ± 30 nm. The diameter and height of the stacks were shaped by the aggregates of tens of triangular Ag nanoplates. The AFM cross-sectional contour showed the clear intervals of the stacks, which was corresponding to the SEM characterization.XRD patterns of the polyelectrolyte-linked NP films before and after thermal post-treatment are showed in

  3. Oysters produce an organic-inorganic adhesive for intertidal reef construction.

    PubMed

    Burkett, Jeremy R; Hight, Lauren M; Kenny, Paul; Wilker, Jonathan J

    2010-09-15

    Coastal ecosystems rely upon oyster reefs to filter water, provide protection from storms, and build habitat for other species. From a chemistry perspective, few details are available to illustrate how these shellfish construct such extensive reef systems. Experiments presented here show that oysters generate a biomineralized adhesive material for aggregating into large communities. This cement is an organic-inorganic hybrid and differs from the surrounding shells by displaying an alternate CaCO(3) crystal form, a cross-linked organic matrix, and an elevated protein content. Emerging themes and unique aspects are both revealed when comparing oyster cement to the adhesives of other marine organisms. The presence of cross-linked proteins provides an analogy to mussel and barnacle adhesives whereas the high inorganic content is exclusive to oysters. With a description of oyster cement in hand we gain strategies for developing synthetic composite materials as well as a better understanding of the components needed for healthy coastal environments.

  4. Spontaneously amplified homochiral organic-inorganic nano-helix complexes via self-proliferation

    NASA Astrophysics Data System (ADS)

    Zhai, Halei; Quan, Yan; Li, Li; Liu, Xiang-Yang; Xu, Xurong; Tang, Ruikang

    2013-03-01

    Most spiral coiled biomaterials in nature, such as gastropod shells, are homochiral, and the favoured chiral feature can be precisely inherited. This inspired us that selected material structures, including chirality, could be specifically replicated into the self-similar populations; however, a physicochemical understanding of the material-based heritage is unknown. We study the homochirality by using calcium phosphate mineralization in the presence of racemic amphiphilic molecules and biological protein. The organic-inorganic hybrid materials with spiral coiling characteristics are produced at the nanoscale. The resulted helixes are chiral with the left- and right-handed characteristics, which are agglomerated hierarchically to from clusters and networks. It is interesting that each cluster or network is homochiral so that the enantiomorphs can be separated readily. Actually, each homochiral architecture is evolved from an original chiral helix, demonstrating the heritage of the matrix chirality during the material proliferation under a racemic condition. By using the Ginzburg-Landaue expression we find that the chiral recognition in the organic-inorganic hybrid formation may be determined by a spontaneous chiral separation and immobilization of asymmetric amphiphilic molecules on the mineral surface, which transferred the structural information from the mother matrix to the descendants by an energetic control. This study shows how biomolecules guide the selective amplification of chiral materials via spontaneous self-replication. Such a strategy can be applied generally in the design and production of artificial materials with self-similar structure characteristics.Most spiral coiled biomaterials in nature, such as gastropod shells, are homochiral, and the favoured chiral feature can be precisely inherited. This inspired us that selected material structures, including chirality, could be specifically replicated into the self-similar populations; however, a

  5. Improved oxidation resistance of organic/inorganic composite atomic layer deposition coated cellulose nanocrystal aerogels

    SciTech Connect

    Smith, Sean W.; Matthews, David J.; Conley, John F.; Buesch, Christian; Simonsen, John

    2014-07-01

    Cellulose nanocrystal (CNC) aerogels are coated with thin conformal layers of Al{sub 2}O{sub 3} using atomic layer deposition to form hybrid organic/inorganic nanocomposites. Electron probe microanalysis and scanning electron microscopy analysis indicated the Al{sub 2}O{sub 3} penetrated more than 1500 μm into the aerogel for extended precursor pulse and exposure/purge times. The measured profile of coated fiber radius versus depth from the aerogel surface agrees well with simulations of precursor penetration depth in modeled aerogel structures. Thermogravimetric analysis shows that Al{sub 2}O{sub 3} coated CNC aerogel nanocomposites do not show significant thermal degradation below 295 °C as compared with 175 °C for uncoated CNC aerogels, an improvement of over 100 °C.

  6. Corrosion resistance properties of organic inorganic hybrid coatings on 2024 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Sun, Dezhi; You, Hong; Chung, Jong Shik

    2005-06-01

    Three kinds of organic-inorganic hybrid coatings modified by tetraethoxysilane (TEOS) were prepared using precursors of vinyltrimethoxysilane (VMS), [3-(methacryloxy)propyl] trimethoxysilane (MPMS) and (3-glycidoxyproyl) trimethoxysilane (GPMS). Properties of corrosion resistance were tested by potentiodynamic polarization curves. Salt spray test and SEM images were also employed to examine the ablitity of coatings to resist long-time corrosion. The results show that hybrid coatings are effective for inhibiting corrosion reaction. Corrosion currents of VMS coating and MPMS coating were 300 times smaller than that of bare sample. The corrosion current of hybrid coatings is smallest when TEOS content reaches 15-20%. It was found that VMS coatings have the strongest ability to resist salt spray corrosion.

  7. Anomalous photovoltaic effect in organic-inorganic hybrid perovskite solar cells.

    PubMed

    Yuan, Yongbo; Li, Tao; Wang, Qi; Xing, Jie; Gruverman, Alexei; Huang, Jinsong

    2017-03-01

    Organic-inorganic hybrid perovskites (OIHPs) have been demonstrated to be highly successful photovoltaic materials yielding very-high-efficiency solar cells. We report the room temperature observation of an anomalous photovoltaic (APV) effect in lateral structure OIHP devices manifested by the device's open-circuit voltage (VOC) that is much larger than the bandgap of OIHPs. The persistent VOC is proportional to the electrode spacing, resembling that of ferroelectric photovoltaic devices. However, the APV effect in OIHP devices is not caused by ferroelectricity. The APV effect can be explained by the formation of tunneling junctions randomly dispersed in the polycrystalline films, which allows the accumulation of photovoltage at a macroscopic level. The formation of internal tunneling junctions as a result of ion migration is visualized with Kelvin probe force microscopy scanning. This observation points out a new avenue for the formation of large and continuously tunable VOC without being limited by the materials' bandgap.

  8. Synthesis and characterization of tunable coumarin- linked glasses as new class of organic/inorganic phosphors

    SciTech Connect

    Luridiana, Alberto; Pretta, Gianluca; Secci, Francesco; Frongia, Angelo; Chiriu, Daniele; Carbonaro, Carlo Maria; Corpino, Riccardo; Ricci, Pier Carlo

    2014-10-21

    It is well known that stilbene with a trans conformation is highly fluorescent. From the viewpoint of molecular structure, coumarins bear a carbon-carbon double bond which is fixed as trans conformation as in trans-stilbene through a lactone structure. This can help to avoid the trans-cis transformation of the double bond under ultraviolet (UV) irradiation as observed in stilbene compounds and results in strong fluorescence and high fluorescence quantum yield and photostability in most of coumarin derivatives. Herein we report some preliminary results about the synthesis and spectroscopic characterization of tunable coumarins and the development of a new linkage protocol for the obtainment of monolayer coumarin-covalently linked glasses. The resulting organic/inorganic coumarin/silica based Self-Assembled Monolayer (SMA) film is proposed as new phosphors for the substituting of critical raw materials, like rare earths, in photonics applications.

  9. Exfoliation of self-assembled 2D organic-inorganic perovskite semiconductors

    SciTech Connect

    Niu, Wendy Baumberg, Jeremy J.; Eiden, Anna; Vijaya Prakash, G.

    2014-04-28

    Ultra-thin flakes of 2D organic-inorganic perovskite (C{sub 6}H{sub 9}C{sub 2}H{sub 4}NH{sub 3}){sub 2}PbI{sub 4} are produced using micromechanical exfoliation. Mono- and few-layer areas are identified using optical and atomic force microscopy, with an interlayer spacing of 1.6 nm. Refractive indices extracted from the optical spectra reveal a sample thickness dependence due to the charge transfer between organic and inorganic layers. These measurements demonstrate a clear difference in the exciton properties between “bulk” (>15 layers) and very thin (<8 layer) regions as a result of the structural rearrangement of organic molecules around the inorganic sheets.

  10. High-performance hybrid organic-inorganic solar cell based on planar n-type silicon

    NASA Astrophysics Data System (ADS)

    Chi, Dan; Qi, Boyuan; Wang, Jizheng; Qu, Shengchun; Wang, Zhanguo

    2014-05-01

    Hybrid organic-inorganic solar cells were fabricated by spin coating the hole transporting conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film on n-type crystalline silicon (n-Si). By incorporating different additives into the PEDOT:PSS, the conductivity and wettability of PEDOT:PSS film are markedly improved, and the device performance is greatly enhanced accordingly. To further optimize the device performance, poly(3-hexylthiophene) (P3HT) layer was inserted between the n-Si and PEDOT:PSS layer. The P3HT layer blocks electrons from diffusing to the PEDOT:PSS, and hence reduces recombination at the anode side. The device eventually exhibits a high power conversion efficiency of 11.52%.

  11. Preparation and properties of organic-inorganic composite superabsorbent based on xanthan gum and loess.

    PubMed

    Feng, Enke; Ma, Guofu; Wu, Yajuan; Wang, Haiping; Lei, Ziqiang

    2014-10-13

    A new, low-cost, and eco-friendly organic-inorganic composite superabsorbent was successfully synthesized in aqueous solution by polymerization xanthan gum (XG), neutralized acrylic acid (AA) and loess using ammonium persulfate (APS) as initiator and N,N-methylenebisacrylamide (MBA) as crosslinker. Structure and morphological characterizations of the composite superabsorbent were investigated by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The loess content, pH values, surfactants, salts and temperature which could affect the swelling and water-retention capabilities of the composite superabsorbent were investigated. The composite superabsorbent exhibits excellent water absorbency (610 g/g in distilled water), pH-stability (pH 5-10), and higher swelling capacity in anionic surfactant solution; on the other hand, the composite superabsorbent can be used for removing multivalent metal ions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Anomalous photovoltaic effect in organic-inorganic hybrid perovskite solar cells

    PubMed Central

    Yuan, Yongbo; Li, Tao; Wang, Qi; Xing, Jie; Gruverman, Alexei; Huang, Jinsong

    2017-01-01

    Organic-inorganic hybrid perovskites (OIHPs) have been demonstrated to be highly successful photovoltaic materials yielding very-high-efficiency solar cells. We report the room temperature observation of an anomalous photovoltaic (APV) effect in lateral structure OIHP devices manifested by the device’s open-circuit voltage (VOC) that is much larger than the bandgap of OIHPs. The persistent VOC is proportional to the electrode spacing, resembling that of ferroelectric photovoltaic devices. However, the APV effect in OIHP devices is not caused by ferroelectricity. The APV effect can be explained by the formation of tunneling junctions randomly dispersed in the polycrystalline films, which allows the accumulation of photovoltage at a macroscopic level. The formation of internal tunneling junctions as a result of ion migration is visualized with Kelvin probe force microscopy scanning. This observation points out a new avenue for the formation of large and continuously tunable VOC without being limited by the materials’ bandgap. PMID:28345043

  13. Photochromic organic-inorganic composite materials prepared by sol-gel processing: properties and potentials

    NASA Astrophysics Data System (ADS)

    Hou, Lisong; Mennig, Martin; Schmidt, Helmut K.

    1994-09-01

    The sol-gel method which features a low-temperature wet-chemical process opens vast possibilities to incorporating organic dyes into solid matrices for various optical applications. In this paper we present our experimental results on the sol-gel derived photochromic organic- inorganic composite (Ormocer) materials following an introductory description of the sol-gel process and a brief review on the state of the art of the photochromic solids prepared using this method. Our photochromic spirooxazine-Ormocer gels and coatings possess better photochromic response and color-change speed than the corresponding photochromic polymer coatings and similar photochemical stability to the latter. Further developments are proposed as to tackle the temperature dependence problem and further tap the potentialities of the photochromic dye-Ormocer material for practical applications.

  14. Mobile Ion Induced Slow Carrier Dynamics in Organic-Inorganic Perovskite CH₃NH₃PbBr₃.

    PubMed

    Chen, Sheng; Wen, Xiaoming; Sheng, Rui; Huang, Shujuan; Deng, Xiaofan; Green, Martin A; Ho-Baillie, Anita

    2016-03-02

    Here, we investigate photoluminescence (PL) and time-resolved photoluminescence (TRPL) in CH3NH3PbBr3 perovskite under continuous illumination, using optical and electro-optical techniques. Under continuous excitation at constant intensity, PL intensity and PL decay (carrier recombination) exhibit excitation intensity dependent reductions in the time scale of seconds to minutes. The enhanced nonradiative recombination is ascribed to light activated negative ions and their accumulation which exhibit a slow dynamics in a time scale of seconds to minutes. The observed result suggests that the organic-inorganic hybrid perovskite is a mixed electronic-ionic semiconductor. The key findings in this work suggest that ions are photoactivated or electro-activated and their accumulation at localized sites can result in a change of carrier dynamics. The findings are therefore useful for the understanding of instability of perovskite solar cells and shed light on the necessary strategies for performance improvement.

  15. The Dynamic Organic/Inorganic Interface of Colloidal PbS Quantum Dots.

    PubMed

    Grisorio, Roberto; Debellis, Doriana; Suranna, Gian Paolo; Gigli, Giuseppe; Giansante, Carlo

    2016-06-01

    Colloidal quantum dots are composed of nanometer-sized crystallites of inorganic semiconductor materials bearing organic molecules at their surface. The organic/inorganic interface markedly affects forms and functions of the quantum dots, therefore its description and control are important for effective application. Herein we demonstrate that archetypal colloidal PbS quantum dots adapt their interface to the surroundings, thus existing in solution phase as equilibrium mixtures with their (metal-)organic ligand and inorganic core components. The interfacial equilibria are dictated by solvent polarity and concentration, show striking size dependence (leading to more stable ligand/core adducts for larger quantum dots), and selectively involve nanocrystal facets. This notion of ligand/core dynamic equilibrium may open novel synthetic paths and refined nanocrystal surface-chemistry strategies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A novel organic-inorganic hybrid composition for controllably synthesizing AgI nanocrystals

    NASA Astrophysics Data System (ADS)

    Liu, Junxue; He, Sheng; An, Changhua; Zhang, Jun

    2017-05-01

    The ability to control the shape and morphology of semiconductor macro/nanocrystals is critical to applications such as photocatalysis, electrocatalysis, photonics and nanoelectronics. Despite significant advances in controlling the shapes by thermal decomposition and solvothermal methods, rigorous shape control by low temperature and aqueous phase controlling remains challenging. Herein, a facile synthetic method based on ethylenediamine assisted precursor transformation technique has been developed for the fabrication of AgI nanocrystals. The central features of our approach are the use of ethylenediamine (en) as complexant and the use of polyvinylpyrrolidone (PVP) as capping surfactants to form Ag(en)xI precursor, which is followed by removing en to form AgI crystals. This work provides new insights into the use of a novel organic-inorganic hybrid composition as precursors for nanocrystals synthesis and offers a potential route to achieve well-defined morphology of inorganic nanostructures with uniform shape and size.

  17. The Rashba effect and indirect electron-hole recombination in hybrid organic-inorganic perovskites.

    PubMed

    Yu, Zhi-Gang

    2017-06-14

    Slow electron-hole recombination, characterized by the bimolecular coefficient k2 in hybrid organic-inorganic perovskites (HOIPs), is a key to their outstanding photovoltaic performance. The measured k2 in HOIPs strongly deviates from k2 ∝ T(-3/2) (T is the temperature) in typical direct-gap semiconductors. Here we show that the observed temperature dependence can be quantitatively accounted for by phonon-assisted recombination of electrons and holes located at the band extrema, which become indirect due to the Rashba effect. Polar optical phonons are most effective in facilitating this indirect recombination. The variation in k2 in HOIPs among different studies in the literature can be attributed to different Rashba strengths in their samples. Our results indicate that the confluence of the Rashba effect and polar coupling transform HOIPs into a unique indirect semiconductor that can accommodate both strong optical absorption and slow carrier dynamics.

  18. Assessment of Hybrid Organic-Inorganic Antimony Sulfides for Earth-Abundant Photovoltaic Applications.

    PubMed

    Yang, Ruo Xi; Butler, Keith T; Walsh, Aron

    2015-12-17

    Hybrid organic-inorganic solar absorbers are currently the subject of intense interest; however, the highest-performing materials contain Pb. Here we assess the potential of three Sb-based semiconductors: (i) Sb2S3, (ii) Cs2Sb8S13, and (iii) (CH3NH3)2Sb8S13. While the crystal structure of Sb2S3 is composed of 1D chains, 2D layers are formed in the ternary cesium and hybrid methylammonium antimony sulfide compounds. In each case, a stereochemically active Sb 5s(2) lone pair is found, resulting in a distorted coordination environment for the Sb cations. The bandgap of the binary sulfide is found to increase, while the ionization potential also changes, upon transition to the more complex compounds. Based on the predicted electronic structure, device configurations are suggested to be suitable for photovoltaic applications.

  19. Formation of thin films of organic-inorganic perovskites for high-efficiency solar cells.

    PubMed

    Stranks, Samuel D; Nayak, Pabitra K; Zhang, Wei; Stergiopoulos, Thomas; Snaith, Henry J

    2015-03-09

    Organic-inorganic perovskites are currently one of the hottest topics in photovoltaic (PV) research, with power conversion efficiencies (PCEs) of cells on a laboratory scale already competing with those of established thin-film PV technologies. Most enhancements have been achieved by improving the quality of the perovskite films, suggesting that the optimization of film formation and crystallization is of paramount importance for further advances. Here, we review the various techniques for film formation and the role of the solvents and precursors in the processes. We address the role chloride ions play in film formation of mixed-halide perovskites, which is an outstanding question in the field. We highlight the material properties that are essential for high-efficiency operation of solar cells, and identify how further improved morphologies might be achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Purcell effect in an organic-inorganic halide perovskite semiconductor microcavity system

    SciTech Connect

    Wang, Jun; Wang, Yafeng; Hu, Tao; Wu, Lin; Shen, Xuechu; Chen, Zhanghai E-mail: zhanghai@fudan.edu.cn; Cao, Runan; Xu, Fei; Da, Peimei; Zheng, Gengfeng; Lu, Jian E-mail: zhanghai@fudan.edu.cn

    2016-01-11

    Organic-inorganic halide perovskite semiconductors with the attractive physics properties, including strong photoluminescence (PL), huge oscillator strengths, and low nonradiative recombination losses, are ideal candidates for studying the light-matter interaction in nanostructures. Here, we demonstrate the coupling of the exciton state and the cavity mode in the lead halide perovskite microcavity system at room temperature. The Purcell effect in the coupling system is clearly observed by using angle-resolved photoluminescence spectra. Kinetic analysis based on time-resolved PL reveals that the spontaneous emission rate of the halide perovskite semiconductor is significantly enhanced at resonance of the exciton energy and the cavity mode. Our results provide the way for developing electrically driven organic polariton lasers, optical devices, and on-chip coherent quantum light sources.

  1. Influence of temperature and light intensity on Ru(II) complex based organic-inorganic device

    SciTech Connect

    Asubay, Sezai; Durap, Feyyaz; Aydemir, Murat; Baysal, Akin; Ocak, Yusuf Selim; Tombak, Ahmet

    2016-03-25

    An organic-inorganic junction was fabricated by forming [Ru(Cy{sub 2}PNHCH{sub 2}-C{sub 4}H{sub 3}O)(η{sup 6}-p-cymene)Cl{sub 2}] complex thin film using spin coating technique on n-Si and evaporating Au metal on the film. It was seen that the structure had perfect rectification property. Current-voltage (I-V) measurements were carried out in dark and under various illumination conditions (between 50-100 mW/cm{sup 2}) and with the temperature range from 303 to 380 K. The structure showed unusually forward and reverse bias temperature and light sensing behaviors. It was seen that the current both in forward and reverse bias increased with the increase in light intensity and temperature.

  2. Organic-inorganic hybrid foams with diatomite addition: Effect on functional properties

    NASA Astrophysics Data System (ADS)

    Verdolotti, L.; D'Auria, M.; Lavorgna, M.; Vollaro, P.; Iannace, S.; Capasso, I.; Galzerano, B.; Caputo, D.; Liguori, B.

    2016-05-01

    Organic-inorganic hybrid foams were prepared by using metakaolin, diatomite as a partial (or total) replacement of metakaolin, as matrix, silicon and whipped protein as pore forming. The foamed systems were hardened at defined temperature and time and then characterized by mechanical point of view through compression tests and by functional point of view through fire reaction and acoustic tests. The experimental findings highlighted that the replacement of diatomite in the formulation affected the morphological structure of the foams and consequently their mechanical properties. In particular, the consolidation mechanism in the diatomite based-hybrid foams changed from geopolymerization to a silicate polycondensation mechanism. Therefore, mechanical performances enhanced with increasing of the diatomite content. Fire reaction tests, such as non-combustibility and cone calorimeter tests, showed positive thermal inertia of samples regardless of the content of diatomite.

  3. Design of novel hybrid organic-inorganic nanostructured biomaterials for immunoassay applications.

    PubMed

    Andrade, G; Barbosa-Stancioli, E F; Piscitelli Mansur, A A; Vasconcelos, W L; Mansur, H S

    2006-12-01

    The purpose of this study was to develop novel hybrid organic-inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically crosslinked network to be tested as solid support on bovine herpesvirus immunoassay. Hybrids were synthesized by reacting PVA with three different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle x-ray scattering synchrotron radiation (SAXS) and x-ray diffraction (XRD). PVA hybrids' chemical functionalities and their interaction with herpesviruses were also characterized by Fourier transform infrared spectroscopy (FTIR). The bioactivity assays were tested through enzyme linked immunosorbent assay (ELISA). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different x-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have shown major vibration bands associated with organic-inorganic chemical groups present in the PVA, PVA-derived by silane modifier and PVA chemically crosslinked by GA. The immunoassay results have shown that PVA hybrids with chemically functionalized structures regulated to some extent the specific bioimmobilization of herpesvirus onto solid phase. We think that it is due to the overall balance of forces associated with van der Waals interaction, hydrophilic and hydrophobic forces and steric hindrance acting at the surface. PVA and PVA-derived hybrid materials were successfully produced with GA crosslinking in a nanometer-scale network. Also, such a PVA-based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.

  4. Electrical spin injection from an organic-based ferrimagnet in a hybrid organic/inorganic heterostructure

    NASA Astrophysics Data System (ADS)

    Johnston-Halperin, Ezekiel

    2012-02-01

    The development of organic-based magnets with room temperature magnetic ordering and semiconducting functionality promises to broaden the field of semiconductor spintronics, providing a route to all-organic spintronic devices and hybrid organic/inorganic structures capable of exploiting the multifunctionality and ease of production in organic systems as well as the well established spintronic functionality of inorganic materials. Our work demonstrates the successful extraction of spin polarized current from the organic-based room temperature ferrimagnetic semiconductor V[TCNE]x (x˜2, TCNE: tetracyanoethylene; TC > 400 K, EG ˜ 0.5 eV, σ˜ 10-2 S/cm) and its subsequent injection into a GaAs/AlGaAs light-emitting diode (LED) [1]. The spin current is detected by monitoring the polarization state of the photons emitted from the LED structure and tracks the magnetization of V[TCNE]x˜2, is weakly temperature dependent, and exhibits heavy hole / light hole asymmetry. This result opens the door to a new class of active, hybrid spintronic devices with multifunctional behavior defined by the optical, electronic and chemical sensitivity of the organic layer. In addition, spin transport in these hybrid structures provides the opportunity to leverage well-characterized inorganic materials as a probe of spin physics in organic and molecular systems and to explore the impact of the hybrid interface on spin injection efficiency. Initial studies exploring the impact of surface passivation of the inorganic layer with self-assembled monolayers of various chemistries will be presented, and additional experimental probes of the interfacial exchange interaction will be discussed. [4pt] [1] ``Electrical Spin Injection from an Organic-Based Ferrimagnet in a Hybrid Organic-Inorganic Heterostructure,'' Lei Fang, K. Deniz Bozdag, Chia-Yi Chen, P.A. Truitt, A.J. Epstein and E. Johnston-Halperin, Phys. Rev. Lett. 106, 156602 (2011).

  5. A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

    NASA Astrophysics Data System (ADS)

    Zuend, A.; Marcolli, C.; Luo, B. P.; Peter, T.

    2008-08-01

    Tropospheric aerosols contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. Interactions between these substances in liquid mixtures lead to discrepancies from ideal thermodynamic behaviour. By means of activity coefficients, non-ideal behaviour can be taken into account. We present here a thermodynamic model named AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) that is able to calculate activity coefficients covering inorganic, organic, and organic-inorganic interactions in aqueous solutions over a wide concentration range. This model is based on the activity coefficient model LIFAC by Yan et al. (1999) that we modified and reparametrised to better describe atmospherically relevant conditions and mixture compositions. Focusing on atmospheric applications we considered H+, Li+, Na+, K+, NH+4, Mg2+, Ca2+, Cl-, Br-, NO-3, HSO-4, and SO2-4 as cations and anions and a wide range of alcohols/polyols composed of the functional groups CHn and OH as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are well represented up to high ionic strength. Most notably, a semi-empirical middle-range parametrisation of direct organic-inorganic interactions in alcohol+water+salt solutions strongly improves the agreement between experimental and modelled activity coefficients. At room temperature, this novel thermodynamic model offers the possibility to compute equilibrium relative humidities, gas/particle partitioning and liquid-liquid phase separations with high accuracy. In further studies, other organic functional groups will be introduced. The model framework is not restricted to specific ions or organic compounds and is therefore also applicable for other research topics.

  6. A thermodynamic model of mixed organic-inorganic aerosols to predict activity coefficients

    NASA Astrophysics Data System (ADS)

    Zuend, A.; Marcolli, C.; Luo, B. P.; Peter, Th.

    2008-03-01

    Tropospheric aerosols contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. Interactions between these substances in liquid mixtures lead to discrepancies from ideal thermodynamic behaviour. By means of activity coefficients, non-ideal behaviour can be taken into account. We present here a thermodynamic model named AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) that is able to calculate activity coefficients covering inorganic, organic, and organic-inorganic interactions in aqueous solutions over a wide concentration range. This model is based on the activity coefficient model LIFAC by Yan et al. (1999) that we modified and reparametrised to better describe atmospherically relevant conditions and mixture compositions. Focusing on atmospheric applications we considered H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl-, Br-, NO3-, HSO4-, and SO42- as cations and anions and a wide range of alcohols/polyols composed of the functional groups CHn and OH as organic compounds. With AIOMFAC, the activities of the components within an aqueous electrolyte solution are well represented up to high ionic strength. Most notably, a semi-empirical middle-range parametrisation of direct organic-inorganic interactions in alcohol + water + salt solutions strongly improves the agreement between experimental and modelled activity coefficients. At room temperature, this novel thermodynamic model offers the possibility to compute equilibrium relative humidities, gas/particle partitioning and liquid-liquid phase separations with high accuracy. In further studies, other organic functional groups will be introduced. The model framework is not restricted to specific ions or organic compounds and is therefore also applicable for other research topics.

  7. Well-ordered organic-inorganic hybrid layered manganese oxide nanocomposites with excellent decolorization performance

    SciTech Connect

    Zhou, Junli; Yu, Lin; Sun, Ming; Ye, Fei; Lan, Bang; Diao, Guiqiang; He, Jun

    2013-02-15

    Well-ordered organic-inorganic hybrid layered manganese oxide nanocomposites (CTAB-Al-MO) with excellent decolorization performance were prepared through a two-step process. Specifically, the MnO{sub 2} nanosheets were self-assembled in the presence of CTAB, and subsequently pillared with Keggin ions. The obtained CTAB-Al-MO with the basal spacing of 1.59 nm could be stable at 300 Degree-Sign C for 2 h and also possesses high total pore volumes (0.41 cm Superscript-Three g{sup -1}) and high specific BET surface area (161 m{sup 2} g{sup -1}), which is nine times larger than that of the pristine (19 m{sup 2} g{sup -1}). Possible formation process for the highly thermal stable CTAB-Al-MO is proposed here. The decolorization experiments of methyl orange showed that the obtained CTAB-Al-MO exhibit excellent performance in wastewater treatment and the decolorization rate could reach 95% within 5 min. - Graphical Abstract: Well-ordered organic-inorganic hybrid LMO nanocomposites (CTAB-Al-MO) with excellent decolorization performance were prepared through a two-step process. Specifically, the MnO{sub 2} nanosheets were self-assembled by CTAB, and subsequently pillared with Keggin ions. Highlights: Black-Right-Pointing-Pointer A two-step synthesis method was used to prepare the CTAB-Al-MO. Black-Right-Pointing-Pointer The CTAB-Al-MO has the large basal spacing and high specific BET surface area. Black-Right-Pointing-Pointer The thermal stability of the well-ordered CTAB-Al-MO could obviously improve. Black-Right-Pointing-Pointer The CTAB-Al-MO exhibits excellent oxidation and absorption ability to remove organic pollutants.

  8. Embedded Metal Electrode for Organic-Inorganic Hybrid Nanowire Solar Cells.

    PubMed

    Um, Han-Don; Choi, Deokjae; Choi, Ahreum; Seo, Ji Hoon; Seo, Kwanyong

    2017-06-27

    We demonstrate here an embedded metal electrode for highly efficient organic-inorganic hybrid nanowire solar cells. The electrode proposed here is an effective alternative to the conventional bus and finger electrode which leads to a localized short circuit at a direct Si/metal contact and has a poor collection efficiency due to a nonoptimized electrode design. In our design, a Ag/SiO2 electrode is embedded into a Si substrate while being positioned between Si nanowire arrays underneath poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), facilitating suppressed recombination at the Si/Ag interface and notable improvements in the fabrication reproducibility. With an optimized microgrid electrode, our 1 cm(2) hybrid solar cells exhibit a power conversion efficiency of up to 16.1% with an open-circuit voltage of 607 mV and a short circuit current density of 34.0 mA/cm(2). This power conversion efficiency is more than twice as high as that of solar cells using a conventional electrode (8.0%). The microgrid electrode significantly minimizes the optical and electrical losses. This reproducibly yields a superior quantum efficiency of 99% at the main solar spectrum wavelength of 600 nm. In particular, our solar cells exhibit a significant increase in the fill factor of 78.3% compared to that of a conventional electrode (61.4%); this is because of the drastic reduction in the metal/contact resistance of the 1 μm-thick Ag electrode. Hence, the use of our embedded microgrid electrode in the construction of an ideal carrier collection path presents an opportunity in the development of highly efficient organic-inorganic hybrid solar cells.

  9. Controlled formation of calcium-phosphate-based hybrid mesocrystals by organic-inorganic co-assembly.

    PubMed

    Zhai, Halei; Chu, Xiaobin; Li, Li; Xu, Xurong; Tang, Ruikang

    2010-11-01

    An understanding of controlled formation of biomimetic mesocrystals is of great importance in materials chemistry and engineering. Here we report that organic-inorganic hybrid plates and even mesocrystals can be conveniently synthesized using a one-pot reaction in a mixed system of protein (bovine serum albumin (BSA)), surfactant (sodium bis(2-ethylhexyl) sulfosuccinate (AOT)) and supersaturated calcium phosphate solution. The morphologies of calcium-phosphate-based products are analogous to the general inorganic crystals but they have abnormal and interesting substructures. The hybrids are constructed by the alternate stacking of organic layer (thickness of 1.31 nm) and well-crystallized inorganic mineral layer (thickness of 2.13 nm) at the nanoscale. Their morphologies (spindle, rhomboid and round) and sizes (200 nm-2 μm) can be tuned gradually by changing BSA, AOT and calcium phosphate concentrations. This modulation effect can be explained by a competition between the anisotropic and isotropic assembly of the ultrathin plate-like units. The anisotropic assembly confers mesocrystal characteristics on the hybrids while the round ones are the results of isotropic assembly. However, the basic lamellar organic-inorganic substructure remains unchanged during the hybrid formation, which is a key factor to ensure the self-assembly from molecule to micrometre scale. A morphological ternary diagram of BSA-AOT-calcium phosphate is used to describe this controlled formation process, providing a feasible strategy to prepare the required materials. This study highlights the cooperative effect of macromolecule (frame structure), small biomolecule (binding sites) and mineral phase (main component) on the generation and regulation of biomimetic hybrid mesocrystals.

  10. Controlled formation of calcium-phosphate-based hybrid mesocrystals by organic-inorganic co-assembly

    NASA Astrophysics Data System (ADS)

    Zhai, Halei; Chu, Xiaobin; Li, Li; Xu, Xurong; Tang, Ruikang

    2010-11-01

    An understanding of controlled formation of biomimetic mesocrystals is of great importance in materials chemistry and engineering. Here we report that organic-inorganic hybrid plates and even mesocrystals can be conveniently synthesized using a one-pot reaction in a mixed system of protein (bovine serum albumin (BSA)), surfactant (sodium bis(2-ethylhexyl) sulfosuccinate (AOT)) and supersaturated calcium phosphate solution. The morphologies of calcium-phosphate-based products are analogous to the general inorganic crystals but they have abnormal and interesting substructures. The hybrids are constructed by the alternate stacking of organic layer (thickness of 1.31 nm) and well-crystallized inorganic mineral layer (thickness of 2.13 nm) at the nanoscale. Their morphologies (spindle, rhomboid and round) and sizes (200 nm-2 μm) can be tuned gradually by changing BSA, AOT and calcium phosphate concentrations. This modulation effect can be explained by a competition between the anisotropic and isotropic assembly of the ultrathin plate-like units. The anisotropic assembly confers mesocrystal characteristics on the hybrids while the round ones are the results of isotropic assembly. However, the basic lamellar organic-inorganic substructure remains unchanged during the hybrid formation, which is a key factor to ensure the self-assembly from molecule to micrometre scale. A morphological ternary diagram of BSA-AOT-calcium phosphate is used to describe this controlled formation process, providing a feasible strategy to prepare the required materials. This study highlights the cooperative effect of macromolecule (frame structure), small biomolecule (binding sites) and mineral phase (main component) on the generation and regulation of biomimetic hybrid mesocrystals.

  11. Semiconducting organic-inorganic nanocomposites by intimately tethering conjugated polymers to inorganic tetrapods

    NASA Astrophysics Data System (ADS)

    Jung, Jaehan; Yoon, Young Jun; Lin, Zhiqun

    2016-04-01

    Semiconducting organic-inorganic nanocomposites were judiciously crafted by placing conjugated polymers in intimate contact with inorganic tetrapods via click reaction. CdSe tetrapods were first synthesized by inducing elongated arms from CdSe zincblende seeds through seed-mediated growth. The subsequent effective inorganic ligand treatment, followed by reacting with short bifunctional ligands, yielded azide-functionalized CdSe tetrapods (i.e., CdSe-N3). Finally, the ethynyl-terminated conjugated polymer poly(3-hexylthiophene) (i.e., P3HT-&z.tbd;) was tethered to CdSe-N3 tetrapods via a catalyst-free alkyne-azide cycloaddition, forming intimate semiconducting P3HT-CdSe tetrapod nanocomposites. Intriguingly, the intimate contact between P3HT and CdSe tetrapod was found to not only render the effective dispersion of CdSe tetrapods in the P3HT matrix, but also facilitate the efficient electronic interaction between these two semiconducting constituents. The successful anchoring of P3HT chains onto CdSe tetrapods was substantiated through Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy measurements. Moreover, the absorption and photoluminescence studies further corroborated the intimate tethering between P3HT and CdSe tetrapods. The effect of the type of bifunctional ligands (i.e., aryl vs. aliphatic ligands) and the size of tetrapods on the device performance of hybrid organic-inorganic solar cells was also scrutinized. Interestingly, P3HT-CdSe tetrapod nanocomposites produced via the use of an aryl bifunctional ligand (i.e., 4-azidobenzoic acid) exhibited an improved photovoltaic performance compared to that synthesized with their aliphatic ligand counterpart (i.e., 5-bromovaleric acid). Clearly, the optimal size of CdSe tetrapods ensuring the effective charge transport in conjunction with the good dispersion of CdSe tetrapods rendered an improved device performance. We envision that the click-reaction strategy enabled by

  12. Simultaneous enzymatic and SERS properties of bifunctional chitosan-modified popcorn-like Au-Ag nanoparticles for high sensitive detection of melamine in milk powder.

    PubMed

    Li, Junrong; Zhang, Guannan; Wang, Lihua; Shen, Aiguo; Hu, Jiming

    2015-08-01

    In this work, we suggest a chitosan-modified popcorn-like Au-Ag nanoparticles (CSPNPs) based assay for high sensitive detection of melamine, in which CSPNPs not only provide with an intrinsic peroxidase-like activity but also act as surface enhanced Raman scattering (SERS) substrates. CSPNPs can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to the charge transfer complex (CTC), which contributes to a tremendous surface-enhanced resonant Raman scattering (SERRS) signals with 632.8 nm laser excitation. The target molecule melamine can generate an additional compound with H2O2, which means the available amount of H2O2 for the oxidation of TMB reduced. Correspondingly, the SERRS intensity of CTC is decreased. The decreased Raman intensity is proportional to the concentration of melamine over a wide range from 10 nM to 50 μM (R(2)=0.989), with a limit of detection (LOD) of 8.51 nM. Moreover, the proposed highly selective method is fully capable of rapid, separation-free detection of melamine in milk powder. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Reactivity I: A Foundation-Level Course for Both Majors and Nonmajors in Integrated Organic, Inorganic, and Biochemistry

    ERIC Educational Resources Information Center

    Schaller, Chris P.; Graham, Kate J.; Johnson, Brian J.; Jones, T. Nicholas; McIntee, Edward J.

    2015-01-01

    A foundation level course is presented that integrates aspects of organic, inorganic and biochemistry in the context of reactivity. The course was designed to serve majors in chemistry and other sciences (biochemistry, biology, nutrition), as well as nursing and pre-health professions students. Themes of the course were designed to highlight a…

  14. Reactivity I: A Foundation-Level Course for Both Majors and Nonmajors in Integrated Organic, Inorganic, and Biochemistry

    ERIC Educational Resources Information Center

    Schaller, Chris P.; Graham, Kate J.; Johnson, Brian J.; Jones, T. Nicholas; McIntee, Edward J.

    2015-01-01

    A foundation level course is presented that integrates aspects of organic, inorganic and biochemistry in the context of reactivity. The course was designed to serve majors in chemistry and other sciences (biochemistry, biology, nutrition), as well as nursing and pre-health professions students. Themes of the course were designed to highlight a…

  15. Organic/inorganic hybrid nanospheres based on hyperbranched poly(ethylene imine) encapsulated into silica for the sorption of toxic metal ions and polycyclic aromatic hydrocarbons from water.

    PubMed

    Arkas, Michael; Tsiourvas, Dimitris

    2009-10-15

    Organic-inorganic hybrid silica nanospheres were prepared through a biomimetic silicification process in water at ambient conditions by the interaction of low cost poly(ethylene imine) hyperbranched polymer with silicic acid. The characterization of these nanoparticles by FTIR spectroscopy, scanning electron microscopy (SEM), zeta-potential and dynamic light scattering (DLS) experiments confirmed that the dendritic polymer was incorporated into the silica network. Preliminary experiments show that these hybrid nanoparticles can be employed for the removal of toxic water contaminants. Hybrid nanospheres' sorption of two completely different categories of pollutants, i.e. metal ions such as Pb(2+), Cd(2+), Hg(2+), Cr(2)O(7)(2-), and polycyclic aromatic hydrocarbons such as pyrene and phenanthrene, was largely enhanced in comparison with the corresponding polymer-free silica nanospheres. This was attributed to the to the formation of conventional metal-ligand and charge-transfer complexes proving that although integrated into the silica network poly(ethylene imine) retains its chemical properties.

  16. A new route for the synthesis of a Ag nanopore-inlay-nanogap structure: integrated Ag-core@graphene-shell@Ag-jacket nanoparticles for high-efficiency SERS detection.

    PubMed

    Qiu, Hengwei; Wang, Minqiang; Yang, Zhi; Jiang, Shouzhen; Liu, Yanjun; Li, Le; Cao, Minghui; Li, Junjie

    2017-08-11

    We present a new route for the synthesis of Ag nanopore-inlay-nanogap structures using creviced graphene-shell encapsulated Cu nanoparticles (Cu@G-NPs) as the sacrificial templates. The as-synthesized integrated Ag-core@graphene-shell@Ag-jacket nanoparticles (AgC@G@AgJ-NPs) presents "chrysanthemum" shapes that contain abundant sub-10 nm size intraparticle nanopores/nanogaps, which can generate huge enhanced electromagnetic fields to support SERS activity, resulting in an average EF > 10(7) due to a high-density of intraparticle and interparticle "hot spots".

  17. Efficiency enhancement in solution processed organic and organic-inorganic perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Xiao, Zhengguo

    Solution processed thin film photovoltaic devices are one of the most promising renewable energy sources. Organic solar cells have been intensively studied due to their advantages of light-weight, flexibility and low-cost materials and manufacturing. The organic-inorganic hybrid perovskite materials have recently shown great potential application in solar cells. The PCE increased dramatically from 3.8% in 2009 to a certified efficiency of 20.1% in 2014. In this dissertation, we focus on the efficiency enhancement for solution processed organic and organic-inorganic solar cells. In Chapter 2, I demonstrated that the crystallinity of the ferroelectric polymer P(VDF-TrFE) at the organic active layer/ electrode interface plays a critical role in the efficiency enhancement of organic solar cells. Then, The ferroelectric P(VDF-TrFE) nanocrystals was synthesized and successfully applied in the low band gap polymers. A high efficiency of 6.8% was achieved in the PCDTBT:PCBM system. Another small polar molecule, TPACA, was also applied to increase the efficiency of organic solar cells. In Chapter 3, I developed a universal approach of solvent fluxing to fabricate graded bulk heterojunction (BHJ) polymer:fullerene films to increase the device efficiency. The solvent fluxing process can extract part of the fullerene inside the BHJ film to the top surface to form graded BHJ. The PCE of the devices after solvent fluxing is increased by 15%--50% compared with the control devices without solvent fluxing. In Chapter 5, a two-step spin coating approach was developed to fabricate the continuous and compact organolead trihalide perovskite (OTP) films. The average PCE of methylammonium lead iodide (MAPbI3) perovskite devices reached 14.5% and 85% of the devices had efficiency above 14%. In Chapter 6, I discovered that the solvent annealing can be used to increase the grain size and crystallinity of the perovskite films. The highest device efficiency reached 15.6%, and device

  18. Development of nanostructured and surface modified semiconductors for hybrid organic-inorganic solar cells.

    SciTech Connect

    Hsu, Julia, W. P.

    2008-09-01

    Solar energy conversion is increasingly being recognized as one of the principal ways to meet future energy needs without causing detrimental environmental impact. Hybrid organic-inorganic solar cells (SCs) are attracting particular interest due to the potential for low cost manufacturing and for use in new applications, such as consumer electronics, architectural integration and light-weight sensors. Key materials advantages of these next generation SCs over conventional semiconductor SCs are in design opportunities--since the different functions of the SCs are carried out by different materials, there are greater materials choices for producing optimized structures. In this project, we explore the hybrid organic-inorganic solar cell system that consists of oxide, primarily ZnO, nanostructures as the electron transporter and poly-(3-hexylthiophene) (P3HT) as the light-absorber and hole transporter. It builds on our capabilities in the solution synthesis of nanostructured semiconducting oxide arrays to this photovoltaic (PV) technology. The three challenges in this hybrid material system for solar applications are (1) achieving inorganic nanostructures with critical spacing that matches the exciton diffusion in the polymer, {approx} 10 nm, (2) infiltrating the polymer completely into the dense nanostructure arrays, and (3) optimizing the interfacial properties to facilitate efficient charge transfer. We have gained an understanding and control over growing oriented ZnO nanorods with sub-50 nm diameters and the required rod-to-rod spacing on various substrates. We have developed novel approaches to infiltrate commercially available P3HT in the narrow spacing between ZnO nanorods. Also, we have begun to explore ways to modify the interfacial properties. In addition, we have established device fabrication and testing capabilities at Sandia for prototype devices. Moreover, the control synthesis of ZnO nanorod arrays lead to the development of an efficient anti

  19. Influence of particle phase state on the hygroscopic behavior of mixed organic-inorganic aerosols

    NASA Astrophysics Data System (ADS)

    Hodas, N.; Zuend, A.; Mui, W.; Flagan, R. C.; Seinfeld, J. H.

    2014-12-01

    Recent work has demonstrated that organic and mixed organic-inorganic particles can exhibit multiple phase states depending on their chemical composition and on ambient conditions such as relative humidity (RH). To explore the extent to which water uptake varies with particle phase behavior, hygroscopic growth factors (HGFs) of nine laboratory-generated, organic and organic-inorganic aerosol systems with physical states ranging from well-mixed liquids, to phase-separated particles, to viscous liquids or semi-solids were measured with the Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe at RH values ranging from 40-90%. Water-uptake measurements were accompanied by HGF and RH-dependent thermodynamic equilibrium calculations using the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model. In addition, AIOMFAC-predicted growth curves are compared to several simplified HGF modeling approaches: (1) representing particles as ideal, well-mixed liquids, (2) forcing a single phase, but accounting for non-ideal interactions through activity coefficient calculations, and (3) a Zdanovskii-Stokes-Robinson-like calculation in which complete separation between the inorganic and organic components is assumed at all RH values, with water-uptake treated separately in each of the individual phases. We observed variability in the characteristics of measured hygroscopic growth curves across aerosol systems with differing phase behaviors, with growth curves approaching smoother, more continuous water uptake with decreasing prevalence of liquid-liquid phase separation and increasing oxygen : carbon ratios of the organic aerosol components. We also observed indirect evidence for the dehydration-induced formation of highly viscous semi-solid phases and for kinetic limitations to the crystallization of ammonium sulfate at low RH for sucrose-containing particles. AIOMFAC-predicted growth curves are generally in good agreement with the HGF

  20. Influence of particle-phase state on the hygroscopic behavior of mixed organic-inorganic aerosols

    NASA Astrophysics Data System (ADS)

    Hodas, N.; Zuend, A.; Mui, W.; Flagan, R. C.; Seinfeld, J. H.

    2015-05-01

    Recent work has demonstrated that organic and mixed organic-inorganic particles can exhibit multiple phase states depending on their chemical composition and on ambient conditions such as relative humidity (RH). To explore the extent to which water uptake varies with particle-phase behavior, hygroscopic growth factors (HGFs) of nine laboratory-generated, organic and organic-inorganic aerosol systems with physical states ranging from well-mixed liquids to phase-separated particles to viscous liquids or semi-solids were measured with the Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe at RH values ranging from 40 to 90%. Water-uptake measurements were accompanied by HGF and RH-dependent thermodynamic equilibrium calculations using the Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients (AIOMFAC) model. In addition, AIOMFAC-predicted growth curves are compared to several simplified HGF modeling approaches: (1) representing particles as ideal, well-mixed liquids; (2) forcing a single phase but accounting for non-ideal interactions through activity coefficient calculations; and (3) a Zdanovskii-Stokes-Robinson-like calculation in which complete separation of the inorganic and organic components is assumed at all RH values, with water uptake treated separately in each of the individual phases. We observed variability in the characteristics of measured hygroscopic growth curves across aerosol systems with differing phase behaviors, with growth curves approaching smoother, more continuous water uptake with decreasing prevalence of liquid-liquid phase separation and increasing oxygen : carbon ratios of the organic aerosol components. We also observed indirect evidence for the dehydration-induced formation of highly viscous semi-solid phases and for kinetic limitations to the crystallization of ammonium sulfate at low RH for sucrose-containing particles. AIOMFAC-predicted growth curves are generally in good agreement with the HGF