Performance enhancement of dye-sensitized solar cells (DSSCs) using a natural sensitizer

NASA Astrophysics Data System (ADS)

Arifin, Zainal; Soeparman, Sudjito; Widhiyanuriyawan, Denny; Sutanto, Bayu; Suyitno

2017-01-01

Dye-sensitized solar cells (DSSCs) based on natural sensitizers have become a topic of significant research because of their urgency and importance in the energy conversion field and the following advantages: ease of fabrication, low-cost solar cell, and usage of nontoxic materials. The natural sensitizer in DSSCs is responsible for the absorption of light as well as the injection of charges to the conduction band of the semiconductor such as TiO2 nanoparticles. In this study, the chlorophyll extracted from papaya leaves was used as a natural sensitizer. Dye molecules were adsorbed by TiO2 nanoparticle surfaces when submerged in the dye solution for 24 h. The concentration of the dye solution influences both the amount of dye loading and the DSSC performance. The amount of adsorbed dye molecules by TiO2 nanoparticle was calculated using a desorption method. As the concentration of dye solution was increased, the dye loading capacity and power conversion efficiency increased. Above 90 mM dye solution concentration, however, the DSSC efficiency decreased because dye precipitated on the TiO2 nanostructure. These characteristics of DSSCs were analyzed under the irradiation of 100 mW/cm2. The best performance of DSSCs was obtained at 90 mM dye solution, with the values of Voc, Jsc, FF, and efficiency of DSSCs being 0.561 V, 0.402 mA/cm2, 41.65%, and 0.094%, respectively.

Ultrafast electron and energy transfer in dye-sensitized iron oxide and oxyhydroxide nanoparticles.

PubMed

Gilbert, Benjamin; Katz, Jordan E; Huse, Nils; Zhang, Xiaoyi; Frandsen, Cathrine; Falcone, Roger W; Waychunas, Glenn A

2013-10-28

An emerging area in chemical science is the study of solid-phase redox reactions using ultrafast time-resolved spectroscopy. We have used molecules of the photoactive dye 2',7'-dichlorofluorescein (DCF) anchored to the surface of iron(III) oxide nanoparticles to create iron(II) surface atoms via photo-initiated interfacial electron transfer. This approach enables time-resolved study of the fate and mobility of electrons within the solid phase. However, complete analysis of the ultrafast processes following dye photoexcitation of the sensitized iron(III) oxide nanoparticles has not been reported. We addressed this topic by performing femtosecond transient absorption (TA) measurements of aqueous suspensions of uncoated and DCF-sensitized iron oxide and oxyhydroxide nanoparticles, and an aqueous iron(III)-dye complex. Following light absorption, excited state relaxation times of the dye of 115-310 fs were found for all samples. Comparison between TA dynamics on uncoated and dye-sensitized hematite nanoparticles revealed the dye de-excitation pathway to consist of a competition between electron and energy transfer to the nanoparticles. We analyzed the TA data for hematite nanoparticles using a four-state model of the dye-sensitized system, finding electron and energy transfer to occur on the same ultrafast timescale. The interfacial electron transfer rates for iron oxides are very close to those previously reported for DCF-sensitized titanium dioxide (for which dye-oxide energy transfer is energetically forbidden) even though the acceptor states are different. Comparison of the alignment of the excited states of the dye and the unoccupied states of these oxides showed that the dye injects into acceptor states of different symmetry (Ti t2gvs. Fe eg).

In silico designing of power conversion efficient organic lead dyes for solar cells using todays innovative approaches to assure renewable energy for future

NASA Astrophysics Data System (ADS)

Kar, Supratik; Roy, Juganta K.; Leszczynski, Jerzy

2017-06-01

Advances in solar cell technology require designing of new organic dye sensitizers for dye-sensitized solar cells with high power conversion efficiency to circumvent the disadvantages of silicon-based solar cells. In silico studies including quantitative structure-property relationship analysis combined with quantum chemical analysis were employed to understand the primary electron transfer mechanism and photo-physical properties of 273 arylamine organic dyes from 11 diverse chemical families explicit to iodine electrolyte. The direct quantitative structure-property relationship models enable identification of the essential electronic and structural attributes necessary for quantifying the molecular prerequisites of 11 classes of arylamine organic dyes, responsible for high power conversion efficiency of dye-sensitized solar cells. Tetrahydroquinoline, N,N'-dialkylaniline and indoline have been least explored classes under arylamine organic dyes for dye-sensitized solar cells. Therefore, the identified properties from the corresponding quantitative structure-property relationship models of the mentioned classes were employed in designing of "lead dyes". Followed by, a series of electrochemical and photo-physical parameters were computed for designed dyes to check the required variables for electron flow of dye-sensitized solar cells. The combined computational techniques yielded seven promising lead dyes each for all three chemical classes considered. Significant (130, 183, and 46%) increment in predicted %power conversion efficiency was observed comparing with the existing dye with highest experimental %power conversion efficiency value for tetrahydroquinoline, N,N'-dialkylaniline and indoline, respectively maintaining required electrochemical parameters.

Multicenter clinical trial on a permanent hair dye containing paratoluenediamine.

PubMed

Foti, Caterina; Balato, Nicola; Cristaudo, Antonio; Patruno, Cataldo; Pigatto, Paolo; Ambrifi, Marina; Bufano, Tamara; Damiani, Giovanni; De Rocco, Mariagrazia; Diani, Marco; Napolitano, Maddalena; Romita, Paolo

2018-08-01

Adverse reactions to hair dyes are frequent and usually caused by sensitization to paraphenylenediamine (PPD). The aim of the study was to evaluate the tolerability of a PPD-free permanent hair dye (Shine On, BioNike, Milan, Italy) containing paratoluenediamine (PTD) in a group of subjects sensitized to PPD. The trial, which carried out at four dermatology centers, included subjects sensitized to PPD that turned out negative to patch testing to PTD. The subjects underwent to an open test consisting in the application of two hair dye colors of the product under examination. Finally, subjects who were negative upon the open test were offered to undergo the usage test with the dye, with dermatological evaluations carried out 48 and 96 hours after product application. Sixty subjects were enrolled. They underwent the open test with two shades of dyes: "color 1 - black," the dye color with the highest concentration of color intermediates, and "color 7.3 - golden blonde," the dye color with the highest number of chemically different color intermediates. No reactions occurred with "color 7.3 - golden blonde," while 3 cases (3 out of 60) showed erythema and edema reactions to color 1. The hair dye usage test was negative for all the 21 subjects that were enrolled. The hair dye evaluated in this study (Shine On, BioNike) can be a valid alternative for subjects sensitized to PPD.

Natural dye sensitizer from cassava (Manihot utilissima) leaves extract and its adsorption onto TiO2 photo-anode

NASA Astrophysics Data System (ADS)

Nurlela; Wibowo, R.; Gunlazuardi, J.

2017-04-01

Interaction between TiO2 and dyes sensitizer have been studied. The chlorophyll presents in the crude leave extract (CLE-dye) from cassava (Manihot utilissima) was immobilized on to the photo-anode, consists of TiO2 supported by fluor doped Tin oxide (SnO2-F) Glass. The TiO2 was prepared by Rapid Breakdown Anodization (RBA) method then immobilized on to glass coated by SnO2-F using doctor blade technique, to give CLE-dye/TiO2/SnO2-F/Glass photo-anode. The prepared photo-anode was characterized by UV-Vis-DRS, FTIR, XRD, SEM, electrochemical and spectro-electrochemical systems. In this study, the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy level of the CLE-dye were empirically determined by cyclic voltammetry method, while spectro-electro-chemistry method was used to determine the coefficient of degradation and formation of the dyes, and diffusion coefficient of the hole recombination as well. Good anchoring between TiO2 with dye extracts (CLE-dye) can be seen from value of dye LUMO energy level (-4.26 eV), which is approaching the conduction band of TiO2 (-4.3 eV). The coefficient of degradation and formation of the CLE-dye showed a quasi reversible and diffusion coefficient hole recombination values were small, indicated that it is quite suitable as a sensitizer in a dyes sensitized solar cell.

Effect of the co-sensitization sequence on the performance of dye-sensitized solar cells with porphyrin and organic dyes.

PubMed

Fan, Suhua; Lu, Xuefeng; Sun, Hong; Zhou, Gang; Chang, Yuan Jay; Wang, Zhong-Sheng

2016-01-14

To obtain a broad spectral response in the visible region, TiO2 film is co-sensitized with a porphyrin dye (FNE57 or FNE59) and an organic dye (FNE46). It is found that the stepwise co-sensitization in one single dye solution followed by in another single dye solution is better than the co-sensitization in a cocktail solution in terms of photovoltaic performance. The stepwise co-sensitization first with a porphyrin dye and then with an organic dye outperforms that in a reverse order. DSSC devices based on co-sensitizers FNE57 + FNE46 and FNE59 + FNE46 with a quasi-solid-state gel electrolyte generate power conversion efficiencies of 7.88% and 8.14%, respectively, which exhibits remarkable efficiency improvements of 61% and 35%, as compared with devices sensitized with the porphyrin dyes FNE57 and FNE59, respectively. Co-sensitization brings about a much improved short-circuit photocurrent due to the complementary absorption of the two sensitizers. The observed enhancement of incident monochromatic photon-to-electron conversion efficiency from individual dye sensitization to co-sensitization is attributed to the improved charge collection efficiency rather than to the light harvesting efficiency. Interestingly, the open-circuit photovoltage for the co-sensitization system comes between the higher voltage for the porphyrin dye (FNE57 or FNE59) and the lower voltage for the organic dye (FNE46), which is well correlated with their electron lifetimes. This finding indicates that not only the spectral complementation but also the electron lifetime should be considered to select dyes for co-sensitization.

Inclusion of aggregation effect to evaluate the performance of organic dyes in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Sun, Kenan; Zhang, Weiyi; Heng, Panpan; Wang, Li; Zhang, Jinglai

2018-05-01

Two new indoline-based D-A-π-A dyes, D3F and D3F2 (see Scheme 1), are developed on the basis of the reported D3 by insertion of one or two F atoms on benzothiadiazole group. Our central aim is to explore high-efficiency organic dyes applied in dye-sensitized solar cells by inclusion of a simple group rather than by employment of new complicated groups. The performance of two new designed organic dyes, D3F and D3F2, is compared with that of D3 from various aspects including absorption spectrum, light harvesting efficiency, driving force, and open-circuit voltage. Besides the isolated dye, the interfacial property between dye and TiO2 surface is studied. D3F and D3F2 do not show absolute superiority than D3 not only for the isolated dyes but also for the monomeric adsorption system. However, D3F and D3F2 would effectively reduce the influence of aggregation resulting in the much smaller intermolecular electronic coupling. Although the aggregation has attracted much attention recently, it is studied alone in most of studies. To comprehensively evaluate the performance of dye-sensitized solar cells, it is necessary to consider aggregation along with electron injection time from dye into TiO2 rather than only static items, such as, band gap and absorption region.

Performance and stability analysis of curcumin dye as a photo sensitizer used in nanostructured ZnO based DSSC

NASA Astrophysics Data System (ADS)

Sinha, D.; De, D.; Ayaz, A.

2018-03-01

Environmental friendly natural dye curcumin extracted from low-cost Curcumina longa stem is used as a photo-sensitizer for the fabrication of ZnO-based dye-sensitized solar cells (DSSC). Nanostructured ZnO is fabricated on a transparent conducting glass (TCO), using a cost-effective chemical bath deposition technique. Scanning electron microscopic images show hexagonal patterned ZnO nano-towers decorated with several nanosteps. The average length of ZnO nano-tower is 5 μm and diameter is 1.2 μm. The UV-Vis spectroscopic study of the curcumin dye is used to understand the light absorption behavior as well as band gap energy of the extracted natural dye. The dye shows wider absorption band-groups over 350-470 nm and 500-600 nm with two peaks positioned at 425 nm and 525 nm. The optical band gap energy and energy band position of the dye is derived which supports its stability and high electron affinity that makes it suitable for light harvesting and effortless electron transfer from dye to the semiconductor or interface between them. FTIR spectrum of curcumin dye-sensitized ZnO-based DSSC shows the presence of anchoring groups and colouring constitutes. The I-V and P-V curves of the fabricated DSSC are measured under simulated light (100 mW/cm2). The highest visible light to electric conversion efficiency of 0.266% (using ITO) and 0.33% (using FTO) is achieved from the curcumin dye-sensitized cell.

EXAFS, ab Initio Molecular Dynamics, and NICIS Spectroscopy Studies on an Organic Dye Model at the Dye-Sensitized Solar Cell Photoelectrode Interface.

PubMed

Liu, Peng; Johansson, Viktor; Trilaksana, Herri; Rosdahl, Jan; Andersson, Gunther G; Kloo, Lars

2017-06-14

The organization of dye molecules in the dye layer adsorbed on the semiconductor substrate in dye-sensitized solar cells has been studied using a combination of theoretical methods and experimental techniques. The model system is based on the simple D-π-A dye L0, which has been chemically modified by substituting the acceptor group CN with Br (L0Br) to offer better X-ray contrast. Experimental EXAFS data based on the Br K-edge backscattering show no obvious difference between dye-sensitized titania powder and titania film samples, thus allowing model systems to be based on powder slurries. Ab initio molecular dynamic (aiMD) calculations have been performed to extract less biased information from the experimental EXASF data. Using the aiMD calculation as input, the EXAFS structural models can be generated a priori that match the experimental data. Our study shows that the L0Br dye adsorbs in the trans-L0Br configuration and that adsorption involves both a proximity to other L0Br dye molecules and the titanium atoms in the TiO 2 substrate. These results indicate direct coordination of the dye molecules to the TiO 2 surface in contrast to previous results on metal-organic dyes. The molecular coverage of L0Br on mesoporous TiO 2 was also estimated using NICIS spectroscopy. The NICISS results emphasized that the L0Br dye on nanoporous titania mainly forms monolayers with a small contribution of multilayer coverage.

Influence of polar solvents on photovoltaic performance of Monascusred dye-sensitized solar cell

NASA Astrophysics Data System (ADS)

Lee, Jae Wook; Kim, Tae Young; Ko, Hyun Seok; Han, Shin; Lee, Suk-Ho; Park, Kyung Hee

Dye-sensitized solar cells (DSSCs) were assembled using natural dyes extracted from Monascus red pigment as a sensitizer. In this work, we studied the adsorption characteristics for harvesting sunlight and the electrochemical behavior for electron transfer in Monascus red DSSC using different solvents. The effect of polar aprotic and protic solvents including water, ethanol, and dimethylsulfoxide (DMSO) used in the sensitization process was investigated for the improvement in conversion efficiency of a cell. As for the Monascus red dye-sensitized electrode in DMSO solvent, the solar cell yields a short-circuit current density (Jsc) of 1.23 mA/cm2, a photovoltage (Voc) of 0.75 V, and a fill factor of 0.72, corresponding to an energy conversion efficiency (η) of 0.66%.

Dye-Sensitized Solar Cells Employing Extracts from Four Cassia Flowers as Natural Sensitizers: Studies on Dye Ingredient Effect on Photovoltaic Performance

NASA Astrophysics Data System (ADS)

Maurya, Ishwar Chandra; Singh, Shalini; Neetu; Gupta, Arun Kumar; Srivastava, Pankaj; Bahadur, Lal

2018-01-01

Natural dyes extracted from four different flowers, namely, Cassia surattensis, Cassia tora, Cassia alata and Cassia occidentalis were used as sensitizers for TiO2-based dye-sensitized solar cells (DSSC). The dye extracts from flowers were obtained by a simple extraction technique and used without any further purification. Optical characteristics of dye extracts were studied. Fourier-transform infrared (FTIR) spectra were used to identify the constituents of extracted dyes. The photovoltaic performance of DSSC employing dye-capped TiO2 photoanodes was measured. The sensitization performance related to anchoring groups present and interaction between dyes with TiO2 surface is demonstrated. An attempt has been made to rationalize the observations by light absorption of the dye extracts and their adsorption on TiO2. The short-circuit current density ( I SC) values ranged from 0.06 mA/cm2 to 0.20 mA/cm2; open circuit voltage ( V OC) from 0.292 V to 0.833 V; fill factor (FF) from 0.7 to 0.9; efficiencies ( η) from 0.013% to 0.15% and incident photon-to-current conversion efficiency from 13% to 20%, were obtained for DSSC using these natural dye extracts. Cassia occidentalis showed the highest current density of 0.20 mA/cm2 and power conversion efficiency of 0.15%, which was due to better interaction between the carbonyl and hydroxyl group of the anthocyanin molecule of C. occidentalis and surface of TiO2 film. The red and blue shift of absorption wavelength of C. surattensis and the blue shift of absorption wavelength of the C. tora, C. alata and C. occidentalis extract in ethanol solution compared to that on TiO2 film has been used for the interpretation of obtained results.

Photo-sensitization of ZnS nanoparticles with renowned ruthenium dyes N3, N719 and Z907 for application in solid state dye sensitized solar cells: A comparative study.

PubMed

Nosheen, Erum; Shah, Syed Mujtaba; Hussain, Hazrat; Murtaza, Ghulam

2016-09-01

This article presents a comprehensive relative report on the grafting of ZnS with renowned ruthenium ((Ru) dyes i.e. N3, N719 and Z907) and gives insight into their charge transfer interaction and sensitization mechanism for boosting solar cell efficiency. Influence of dye concentration on cell performance is also reported here. ZnS nanoparticles synthesized by a simple coprecipitation method with an average particle size of 15±2nm were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Elemental dispersive X-ray analysis (EDAX), tunneling electron microscopy (TEM) and UV-Visible (UV-Vis) spectroscopy. UV-Vis, photoluminescence (PL) and Fourier transform infra-red (FT-IR) spectroscopy confirms the successful grafting of these dyes over ZnS nanoparticles surface. Low-energy metal-to-ligand charge-transfer transition (MLCT) bands of dyes are mainly affected on grafting over the nanoparticle surface. Moreover their current voltage (I-V) results confirm the efficiency enhancement in ZnS solid state dye sensitized solar cells (SSDSSCs) owing to effective sensitization of this material with Ru dyes and helps in finding the optimum dye concentration for nanoparticles sensitization. Highest rise in overall solar cell efficiency i.e. 64% of the reference device has been observed for 0.3mM N719-ZnS sample owing to increased open circuit voltage (Voc) and fill factor (FF). Experimental and proposed results were found in good agreement with each other. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance of dye-sensitized solar cells fabricated with extracts from fruits of ivy gourd and flowers of red frangipani as sensitizers

NASA Astrophysics Data System (ADS)

Shanmugam, Vinoth; Manoharan, Subbaiah; Anandan, Sambandam; Murugan, Ramaswamy

2013-03-01

Natural dyes extracted from fruits of ivy gourd and flowers of red frangipani were used as sensitizers to fabricate dye sensitized solar cells (DSSCs). The UV-Vis absorption spectroscopy, Fourier transform infrared (FTIR), Fourier transform Raman (FT-Raman) and liquid chromatography-mass spectrometry (LC-MS) studies indicated the presence of β-carotene in the fruits of ivy gourd and anthocyanins in the flowers of red frangipani. The extract of the flowers of red frangipani exhibits higher photosensitized performance compared to the fruits of ivy gourd and this is due to the better charge transfer between the dyes of flowers of red frangipani and the TiO2 photoanode surface.

An electro-optical and electron injection study of benzothiazole-based squaraine dyes as efficient dye-sensitized solar cell materials: a first principles study.

PubMed

Al-Fahdan, Najat Saeed; Asiri, Abdullah M; Irfan, Ahmad; Basaif, Salem A; El-Shishtawy, Reda M

2014-12-01

Squaraine dyes have attracted significant attention in many areas of daily life from biomedical imaging to semiconducting materials. Moreover, these dyes are used as photoactive materials in the field of solar cells. In the present study, we investigated the structural, electronic, photophysical, and charge transport properties of six benzothiazole-based squaraine dyes (Cis-SQ1-Cis-SQ3 and Trans-SQ1-Trans-SQ3). The effect of electron donating (-OCH3) and electron withdrawing (-COOH) groups was investigated intensively. Ground state geometry and frequency calculations were performed by applying density functional theory (DFT) at B3LYP/6-31G** level of theory. Absorption spectra were computed in chloroform at the time-dependent DFT/B3LYP/6-31G** level of theory. The driving force of electron injection (ΔG (inject)), relative driving force of electron injection (ΔG r (inject)), electronic coupling constants (|VRP|) and light harvesting efficiency (LHE) of all six compounds were calculated and compared with previously studied sensitizers. The ΔG (inject), ΔG r (inject) and |VRP| of all six compounds revealed that these sensitizers would be efficient dye-sensitized solar cell materials. Cis/Trans-SQ3 exhibited superior LHE as compared to other derivatives. The Cis/Trans geometric effect was studied and discussed with regard to electro-optical and charge transport properties.

Theoretical Study of Electron Transfer Properties of Squaraine Dyes for Dye Sensitized Solar Cell

NASA Astrophysics Data System (ADS)

Juwita, Ratna; Tsai, Hui-Hsu Gavin

2018-01-01

The environmental issues and high cost of Ru create many scientists to explore cheaper and safer sensitizer as alternative for dye sensitized solar cells (DSCs). Dyes play an important role in solar energy conversion efficiency. The squaraine (SQ) dyes has good spectral match with the solar spectra, therefore, SQ dyes have great potential for the applications in DSCs. SQ01_CA is an unsymmetrical SQ dye, reported by Grätzel and colleagues in 2007, featuring a D-π-spacer-A framework and has a carboxylic acid anchoring group. The electron donating ability of indolium in SQ01_CA and SQ01_CAA dyes is relatively weak, better performance may be achieved by introducing an additional donor moiety into indolium [1]. In this study, we investigate six unsymmetrical SQ dyes adsorbed on a (TiO2)38 cluster [2] using density functional theory (DFT) and time-dependent DFT to study electron transfer properties of squaraine dyes on their photophysical. SQ01_CA, WH-SQ01_CA, and WH-SQ02_CA use a carboxylic acid group as its electron acceptor. Furthermore, SQ01_CAA, WH-SQ01_CAA, and WH-SQ02_CAA use a cyanoacrylic acid group as its electron acceptor. WH-SQ01_CA and WH-SQ01_CAA have an alkyl, while WH-SQ02_CA and WH-SQ02_CAA have alkoxyl substituted diarylamines to the indolium donor of sensitizer SQ01_CA. Our calculations show with additional diarylamines in donor tail of WH-SQ02_CAA, the SQ dyes have red-shifted absorption and have slightly larger probability of electron density transferred to TiO2 moiety. Furthermore, an additional -CN group as electron a withdrawing group in the acceptor exhibits red-shifted absorption and enhances the electron density transferred to TiO2 and anchoring moiety after photo-excitation. The tendency of calculated probabilities of electron density being delocalized into TiO2 and driving force for excited-state electron injection of these studied SQ dyes is compatible with their experimentally observed.

Influence of polar solvents on photovoltaic performance of Monascusred dye-sensitized solar cell.

PubMed

Lee, Jae Wook; Kim, Tae Young; Ko, Hyun Seok; Han, Shin; Lee, Suk-Ho; Park, Kyung Hee

2014-05-21

Dye-sensitized solar cells (DSSCs) were assembled using natural dyes extracted from Monascus red pigment as a sensitizer. In this work, we studied the adsorption characteristics for harvesting sunlight and the electrochemical behavior for electron transfer in Monascus red DSSC using different solvents. The effect of polar aprotic and protic solvents including water, ethanol, and dimethylsulfoxide (DMSO) used in the sensitization process was investigated for the improvement in conversion efficiency of a cell. As for the Monascus red dye-sensitized electrode in DMSO solvent, the solar cell yields a short-circuit current density (Jsc) of 1.23mA/cm(2), a photovoltage (Voc) of 0.75V, and a fill factor of 0.72, corresponding to an energy conversion efficiency (η) of 0.66%. Copyright © 2014 Elsevier B.V. All rights reserved.

Personal use of hair dyes and the risk of bladder cancer: results of a meta-analysis.

PubMed Central

Huncharek, Michael; Kupelnick, Bruce

2005-01-01

OBJECTIVE: This study examined the methodology of observational studies that explored an association between personal use of hair dye products and the risk of bladder cancer. METHODS: Data were pooled from epidemiological studies using a general variance-based meta-analytic method that employed confidence intervals. The outcome of interest was a summary relative risk (RRs) reflecting the risk of bladder cancer development associated with use of hair dye products vs. non-use. Sensitivity analyses were performed to explain any observed statistical heterogeneity and to explore the influence of specific study characteristics of the summary estimate of effect. RESULTS: Initially combining homogenous data from six case-control and one cohort study yielded a non-significant RR of 1.01 (0.92, 1.11), suggesting no association between hair dye use and bladder cancer development. Sensitivity analyses examining the influence of hair dye type, color, and study design on this suspected association showed that uncontrolled confounding and design limitations contributed to a spurious non-significant summary RR. The sensitivity analyses yielded statistically significant RRs ranging from 1.22 (1.11, 1.51) to 1.50 (1.30, 1.98), indicating that personal use of hair dye products increases bladder cancer risk by 22% to 50% vs. non-use. CONCLUSION: The available epidemiological data suggest an association between personal use of hair dye products and increased risk of bladder cancer. PMID:15736329

Synthesis and characterization of organic dyes with various electron-accepting substituents for p-type dye-sensitized solar cells.

PubMed

Weidelener, Martin; Powar, Satvasheel; Kast, Hannelore; Yu, Ze; Boix, Pablo P; Li, Chen; Müllen, Klaus; Geiger, Thomas; Kuster, Simon; Nüesch, Frank; Bach, Udo; Mishra, Amaresh; Bäuerle, Peter

2014-11-01

Four new donor-π-acceptor dyes differing in their acceptor group have been synthesized and employed as model systems to study the influence of the acceptor groups on the photophysical properties and in NiO-based p-type dye-sensitized solar cells. UV/Vis absorption spectra showed a broad range of absorption coverage with maxima between 331 and 653 nm. Redox potentials as well as HOMO and LUMO energies of the dyes were determined from cyclic voltammetry measurements and evaluated concerning their potential use as sensitizers in p-type dye-sensitized solar cells (p-DSCs). Quantum-chemical density functional theory calculations gave further insight into the frontier orbital distributions, which are relevant for the electronic processes in p-DSCs. In p-DSCs using an iodide/triiodide-based electrolyte, the polycyclic 9,10-dicyano-acenaphtho[1,2-b]quinoxaline (DCANQ) acceptor-containing dye gave the highest power conversion efficiency of 0.08%, which is comparable to that obtained with the perylenemonoimide (PMI)-containing dye. Interestingly, devices containing the DCANQ-based dye achieve a higher V(OC) of 163 mV compared to 158 mV for the PMI-containing dye. The result was further confirmed by impedance spectroscopic analysis showing higher recombination resistance and thus a lower recombination rate for devices containing the DCANQ dye than for PMI dye-based devices. However, the use of the strong electron-accepting tricyanofurane (TCF) group played a negative role in the device performance, yielding an efficiency of only 0.01% due to a low-lying LUMO energy level, thus resulting in an insufficient driving force for efficient dye regeneration. The results demonstrate that a careful molecular design with a proper choice of the acceptor unit is essential for development of sensitizers for p-DSCs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optical and Photovoltaic Properties of Thieno[3,2-b]thiophene-Based Push-Pull Organic Dyes with Different Anchoring Groups for Dye-Sensitized Solar Cells.

PubMed

Fernandes, Sara S M; Castro, M Cidália R; Pereira, Ana Isabel; Mendes, Adélio; Serpa, Carlos; Pina, João; Justino, Licínia L G; Burrows, Hugh D; Raposo, M Manuela M

2017-12-31

The effect of anchoring groups on the optical and electrochemical properties of triphenylamine-thienothiophenes, and on the photovoltaic performance of DSSCs photosensitized with the prepared dyes, was studied using newly synthesized compounds with cyanoacetic acid or rhodanine-3-acetic acid groups. Precursor aldehydes were synthesized through Suzuki cross-coupling, whereas Knoevenagel condensation of these with 2-cyanoacetic acid or rhodanine-3-acetic acid afforded the final push-pull dyes. A comprehensive photophysical study was performed in solution and in the solid state. The femtosecond time-resolved transient absorption spectra for the synthesized dyes were obtained following photoexcitation in solution and for the dyes adsorbed to TiO 2 mesoporous films. Information on conformation, electronic structure, and electron distribution was obtained by density functional theory (DFT) and time-dependent DFT calculations. Triphenylamine-thienothiophene functionalized with a cyanoacetic acid anchoring group displayed the highest conversion efficiency (3.68%) as the dye sensitizer in nanocrystalline TiO 2 solar cells. Coadsorption studies were performed for this dye with the ruthenium-based N719 dye, and they showed dye power conversion efficiencies enhanced by 20-64%. The best cell performance obtained with the coadsorbed N719 and cyanoacetic dye showed an efficiency of 6.05%.

Optical and Photovoltaic Properties of Thieno[3,2-b]thiophene-Based Push–Pull Organic Dyes with Different Anchoring Groups for Dye-Sensitized Solar Cells

PubMed Central

2017-01-01

The effect of anchoring groups on the optical and electrochemical properties of triphenylamine-thienothiophenes, and on the photovoltaic performance of DSSCs photosensitized with the prepared dyes, was studied using newly synthesized compounds with cyanoacetic acid or rhodanine-3-acetic acid groups. Precursor aldehydes were synthesized through Suzuki cross-coupling, whereas Knoevenagel condensation of these with 2-cyanoacetic acid or rhodanine-3-acetic acid afforded the final push–pull dyes. A comprehensive photophysical study was performed in solution and in the solid state. The femtosecond time-resolved transient absorption spectra for the synthesized dyes were obtained following photoexcitation in solution and for the dyes adsorbed to TiO2 mesoporous films. Information on conformation, electronic structure, and electron distribution was obtained by density functional theory (DFT) and time-dependent DFT calculations. Triphenylamine–thienothiophene functionalized with a cyanoacetic acid anchoring group displayed the highest conversion efficiency (3.68%) as the dye sensitizer in nanocrystalline TiO2 solar cells. Coadsorption studies were performed for this dye with the ruthenium-based N719 dye, and they showed dye power conversion efficiencies enhanced by 20–64%. The best cell performance obtained with the coadsorbed N719 and cyanoacetic dye showed an efficiency of 6.05%. PMID:29302638

A Blue Diketopyrrolopyrrole Sensitizer with High Efficiency in Nickel-Oxide-based Dye-Sensitized Solar Cells.

PubMed

Farré, Yoann; Raissi, Mahfoudh; Fihey, Arnaud; Pellegrin, Yann; Blart, Errol; Jacquemin, Denis; Odobel, Fabrice

2017-06-22

We prepared a series of four new diketopyrrolopyrroles (DPPs)-based sensitizers that exhibit high-molar extinction coefficients, extended absorption into the long wavelengths, and well-suited photoredox properties to act as sensitizers in p-type dye-sensitized solar cells (p-DSSCs). These new DPP dyes, composed of a thienyl DPP core, are substituted on one end either by a thiophene carboxylic (Th) or a 4,4'-[(phenyl)aza]dibenzoic acid as anchoring group and, on the other extremity, either by a proton or a naphthalene diimide (NDI) moiety. These new dyes were completely characterized by absorption and emission spectroscopy along with electrochemistry and they were modeled by time-dependent DFT (TD-DFT) quantum chemical calculations. The photovoltaic study in p-DSSC with iodine-based electrolyte reveals that the Th-DPP-NDI dye is particularly efficient (J sc =7.38 mA cm -2 ; V oc =147 mV; FF=0.32; η=0.35 %) and quite active in the low-energy region of the solar spectrum (above 700 nm), where only a few NiO dyes are effective. To illustrate the potential of DPP dyes in photocathodes, we designed a highly efficient tandem DSSC composed of a TiO 2 photoanode sensitized by the dye D35 and a NiO photocathode sensitized by Th-DPP-NDI. This tandem DSSC gives the highest performances ever reported (J sc =6.73 mA cm -2 ; V oc =910 mV; η=4.1 %) and, importantly, the tandem cell outcompetes with the sub-cells. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bi-functional ion exchangers for enhanced performance of dye-sensitized solar cells.

PubMed

Kong, Eui-Hyun; Chang, Yong-June; Lim, Jongchul; Kim, Back-Hyun; Lee, Jung-Hoon; Kwon, Do-Kyun; Park, Taiho; Jang, Hyun Myung

2013-07-28

Ion exchange using aerosol OT (AOT) offers dye adsorption twice as fast as known methods. Moreover, it suppresses the dye-agglomeration that may cause insufficient dye-coverage on the photoelectrode surface. Consequently, its dual function of fast dye-loading and higher dye-coverage significantly improves the power conversion efficiency of dye-sensitized solar cells.

Metal oxide-encapsulated dye-sensitized photoanodes for dye-sensitized solar cells

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

Hupp, Joseph T.; Son, Ho-Jin

2016-01-12

Dye-sensitized semiconducting metal oxide films for photoanodes, photoanodes incorporating the films and DSCs incorporating the photoanodes are provided. Also provided are methods for making the dye sensitized semiconducting metal oxide films. The methods of making the films are based on the deposition of an encapsulating layer of a semiconducting metal oxide around the molecular anchoring groups of photosensitizing dye molecules adsorbed to a porous film of the semiconducting metal oxide. The encapsulating layer of semiconducting metal oxide is formed in such a way that it is not coated over the chromophores of the adsorbed dye molecules and, therefore, allows themore » dye molecules to remain electrochemically addressable.« less

Stability and efficiency of dye-sensitized solar cells based on papaya-leaf dye.

PubMed

Suyitno, Suyitno; Saputra, Trisma Jaya; Supriyanto, Agus; Arifin, Zainal

2015-09-05

The present article reports on the enhancement of the performance and stability of natural dye-based dye-sensitized solar cells (DSSCs). Natural dyes extracted from papaya leaves (PL) were investigated as sensitizers in TiO2-based DSSCs and evaluated in comparison with N719 dye. The acidity of the papaya-leaf extract dyes was tuned by adding benzoic acid. The TiO2 film-coated fluorine-doped tin oxide glass substrates were prepared using the doctor-blade method, followed by sintering at 450 °C. The counter electrode was coated by chemically deposited catalytic platinum. The working electrodes were immersed in N719 dye and papaya dye solutions with concentrations of 8 g/100 mL. The absorbance spectra of the dyes were obtained by ultra-violet-visible spectroscopy. The energy levels of the dyes were measured by the method of cyclic voltammetry. In addition, Fourier transform infrared spectroscopy was used to determine the characteristic functionalities of the dye molecules. The DSSC based on the N719 dye displayed a highest efficiency of 0.87% whereas those based on papaya-leaf dye achieved 0.28% at pH 3.5. The observed improved efficiency of the latter was attributed to the increased current density value. Furthermore, the DSSCs based on papaya-leaf dye with pH 3.5-4 exhibited better stability than those based on N719 dye. However, further studies are required to improve the current density and stability of natural dye-based DSSCs, including the investigation of alternative dye extraction routes, such as isolating the pure chlorophyll from papaya leaves and stabilizing it. Copyright © 2015 Elsevier B.V. All rights reserved.

Stability and efficiency of dye-sensitized solar cells based on papaya-leaf dye

NASA Astrophysics Data System (ADS)

Suyitno, Suyitno; Saputra, Trisma Jaya; Supriyanto, Agus; Arifin, Zainal

2015-09-01

The present article reports on the enhancement of the performance and stability of natural dye-based dye-sensitized solar cells (DSSCs). Natural dyes extracted from papaya leaves (PL) were investigated as sensitizers in TiO2-based DSSCs and evaluated in comparison with N719 dye. The acidity of the papaya-leaf extract dyes was tuned by adding benzoic acid. The TiO2 film-coated fluorine-doped tin oxide glass substrates were prepared using the doctor-blade method, followed by sintering at 450 °C. The counter electrode was coated by chemically deposited catalytic platinum. The working electrodes were immersed in N719 dye and papaya dye solutions with concentrations of 8 g/100 mL. The absorbance spectra of the dyes were obtained by ultra-violet-visible spectroscopy. The energy levels of the dyes were measured by the method of cyclic voltammetry. In addition, Fourier transform infrared spectroscopy was used to determine the characteristic functionalities of the dye molecules. The DSSC based on the N719 dye displayed a highest efficiency of 0.87% whereas those based on papaya-leaf dye achieved 0.28% at pH 3.5. The observed improved efficiency of the latter was attributed to the increased current density value. Furthermore, the DSSCs based on papaya-leaf dye with pH 3.5-4 exhibited better stability than those based on N719 dye. However, further studies are required to improve the current density and stability of natural dye-based DSSCs, including the investigation of alternative dye extraction routes, such as isolating the pure chlorophyll from papaya leaves and stabilizing it.

Conversion efficiency versus sensitizer for electrospun TiO2 nanorod electrodes in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Jose, R.; Kumar, A.; Thavasi, V.; Ramakrishna, S.

2008-10-01

The electrochemical and optical properties of three indoline dyes, namely C35H28N2O2 (D131), C37H30N2O3S2 (D102), and C42H35N3O4S3 (D149), were studied and compared with that of the N3 dye. D131 has the largest bandgap and lowest unoccupied molecular orbital (LUMO) energies compared to the other dyes. A size-dependent variation in the absorptivity of the indoline dyes was observed—the absorptivity increased with increase in the molecular size. The dyes were anchored onto TiO2 nanorods. The TiO2 nanorods were obtained by electrospinning a polymeric solution containing titanium isopropoxide and polyvinylpyrrolidone and subsequent sintering of the as-spun composite fibers. Absorption spectral measurements of the dye-anchored TiO2 showed blue shifts in the excitonic transition of the indoline dyes, the magnitude of which increased with decrease in the molecular size. Dye-sensitized solar cells (DSSCs) were fabricated using the indoline dyes, TiO2 nanorods, and iodide/triiodide electrolyte. The D131 dye showed comparable energy conversion efficiency (η) to that of the N3 dye. A systematic change in the short circuit current density (JSC) and η of the indoline DSSCs was observed. The observed variation in JC is most likely originated from the difference in the electronic coupling strengths between the dye and the TiO2.

Novel Blue Organic Dye for Dye-Sensitized Solar Cells Achieving High Efficiency in Cobalt-Based Electrolytes and by Co-Sensitization.

PubMed

Hao, Yan; Saygili, Yasemin; Cong, Jiayan; Eriksson, Anna; Yang, Wenxing; Zhang, Jinbao; Polanski, Enrico; Nonomura, Kazuteru; Zakeeruddin, Shaik Mohammed; Grätzel, Michael; Hagfeldt, Anders; Boschloo, Gerrit

2016-12-07

Blue and green dyes as well as NIR-absorbing dyes have attracted great interest because of their excellent ability of absorbing the incident photons in the red and near-infrared range region. A novel blue D-π-A dye (Dyenamo Blue), based on the diketopyrrolopyrrole (DPP)-core, has been designed and synthesized. Assembled with the cobalt bipyridine-based electrolytes, the device with Dyenamo Blue achieved a satisfying efficiency of 7.3% under one sun (AM1.5 G). The co-sensitization strategy was further applied on this blue organic dye together with a red D-π-A dye (D35). The successful co-sensitization outperformed a panchromatic light absorption and improved the photocurrent density; this in addition to the open-circuit potential result in an efficiency of 8.7%. The extended absorption of the sensitization and the slower recombination reaction between the blue dye and TiO 2 surface inhibited by the additional red sensitizer could be the two main reasons for the higher performance. In conclusion, from the results, the highly efficient cobalt-based DSSCs could be achieved with the co-sensitization between red and blue D-π-A organic dyes with a proper design, which showed us the possibility of applying this strategy for future high-performance solar cells.

Sensitization of Nanocrystalline Metal Oxides with a Phosphonate-Functionalized Perylene Diimide for Photoelectrochemical Water Oxidation with a CoOx Catalyst.

PubMed

Kirner, Joel T; Finke, Richard G

2017-08-23

A planar organic thin film composed of a perylene diimide dye (N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoO x ) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MO x ) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO 2 > SnO 2 ≫ WO 3 . Despite highest initial dye loading on TiO 2 films, photocurrent with hydroquinone (H 2 Q) sacrificial reductant in pH 7 aqueous solution is much higher on SnO 2 films, likely due to a higher driving force for charge injection into the more positive conduction band energy of SnO 2 . Dyeing conditions and SnO 2 film thickness were subsequently optimized to achieve light-harvesting efficiency >99% at the λ max of the dye, and absorbed photon-to-current efficiency of 13% with H 2 Q, a 2-fold improvement over the previous thin-film architecture. A CoO x water-oxidation catalyst was photoelectrochemically deposited, allowing for photoelectrochemical water oxidation with a faradaic efficiency of 31 ± 7%, thus demonstrating the second example of a water-oxidizing, dye-sensitized photoelectrolysis cell composed entirely of earth-abundant materials. However, deposition of CoO x always results in lower photocurrent due to enhanced recombination between catalyst and photoinjected electrons in SnO 2 , as confirmed by open-circuit photovoltage measurements. Possible future studies to enhance photoanode performance are discussed, including alternative catalyst deposition strategies or structural derivatization of the perylene dye.

Sensitization of Nanocrystalline Metal Oxides with a Phosphonate-Functionalized Perylene Diimide for Photoelectrochemical Water Oxidation with a CoO x Catalyst

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

Kirner, Joel T.; Finke, Richard G.

A planar organic thin film composed of a perylene diimide dye (N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoO x) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MO x) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO 2 > SnO 2 >> WO 3. Despite highest initial dye loading on TiO 2 films, photocurrent with hydroquinone (H 2Q) sacrificial reductant in pH 7 aqueous solution is much higher on SnO 2 films, likelymore » due to a higher driving force for charge injection into the more positive conduction band energy of SnO 2. Dyeing conditions and SnO 2 film thickness were subsequently optimized to achieve light-harvesting efficiency >99% at the λmax of the dye, and absorbed photon-to-current efficiency of 13% with H 2Q, a 2-fold improvement over the previous thin-film architecture. A CoO x water-oxidation catalyst was photoelectrochemically deposited, allowing for photoelectrochemical water oxidation with a faradaic efficiency of 31 ± 7%, thus demonstrating the second example of a water-oxidizing, dye-sensitized photoelectrolysis cell composed entirely of earth-abundant materials. However, deposition of CoO x always results in lower photocurrent due to enhanced recombination between catalyst and photoinjected electrons in SnO 2, as confirmed by open-circuit photovoltage measurements. Possible future studies to enhance photoanode performance are also discussed, including alternative catalyst deposition strategies or structural derivatization of the perylene dye.« less

Sensitization of Nanocrystalline Metal Oxides with a Phosphonate-Functionalized Perylene Diimide for Photoelectrochemical Water Oxidation with a CoO x Catalyst

DOE PAGES

Kirner, Joel T.; Finke, Richard G.

2017-07-20

A planar organic thin film composed of a perylene diimide dye (N,N'-bis(phosphonomethyl)-3,4,9,10-perylenediimide, PMPDI) with photoelectrochemically deposited cobalt oxide (CoO x) catalyst was previously shown to photoelectrochemically oxidize water (DOI: 10.1021/am405598w). Herein, the same PMPDI dye is studied for the sensitization of different nanostructured metal oxide (nano-MO x) films in a dye-sensitized photoelectrochemical cell architecture. Dye adsorption kinetics and saturation decreases in the order TiO 2 > SnO 2 >> WO 3. Despite highest initial dye loading on TiO 2 films, photocurrent with hydroquinone (H 2Q) sacrificial reductant in pH 7 aqueous solution is much higher on SnO 2 films, likelymore » due to a higher driving force for charge injection into the more positive conduction band energy of SnO 2. Dyeing conditions and SnO 2 film thickness were subsequently optimized to achieve light-harvesting efficiency >99% at the λmax of the dye, and absorbed photon-to-current efficiency of 13% with H 2Q, a 2-fold improvement over the previous thin-film architecture. A CoO x water-oxidation catalyst was photoelectrochemically deposited, allowing for photoelectrochemical water oxidation with a faradaic efficiency of 31 ± 7%, thus demonstrating the second example of a water-oxidizing, dye-sensitized photoelectrolysis cell composed entirely of earth-abundant materials. However, deposition of CoO x always results in lower photocurrent due to enhanced recombination between catalyst and photoinjected electrons in SnO 2, as confirmed by open-circuit photovoltage measurements. Possible future studies to enhance photoanode performance are also discussed, including alternative catalyst deposition strategies or structural derivatization of the perylene dye.« less

Ultrafast and slow charge recombination dynamics of diketopyrrolopyrrole-NiO dye sensitized solar cells.

PubMed

Zhang, Lei; Favereau, Ludovic; Farré, Yoann; Mijangos, Edgar; Pellegrin, Yann; Blart, Errol; Odobel, Fabrice; Hammarström, Leif

2016-07-21

In a photophysical study, two diketopyrrolopyrrole (DPP)-based sensitizers functionalized with 4-thiophenecarboxylic acid as an anchoring group and a bromo (DPPBr) or dicyanovinyl (DPPCN2) group, and a dyad consisting of a DPP unit linked to a naphthalenediimide group (DPP-NDI), were investigated both in solution and grafted on mesoporous NiO films. Femtosecond transient absorption measurements indicate that ultrafast hole injection occurred predominantly on a timescale of ∼200 fs, whereas the subsequent charge recombination occurred on a surprisingly wide range of timescales, from tens of ps to tens of μs; this kinetic heterogeneity is much greater than is typically observed for dye-sensitized TiO2 or ZnO. Also, in contrast to what is typically observed for dye-sensitized TiO2, there was no significant dependence on the excitation power of the recombination kinetics, which can be explained by the hole density being comparatively higher near the valence band of NiO before excitation. The additional acceptor group in DPP-NDI provided a rapid electron shift and stabilized charge separation up to the μs timescale. This enabled efficient (∼95%) regeneration of NDI by a Co(III)(dtb)3 electrolyte (dtb = 4,4'-di-tert-butyl-2,2'-bipyridine), according to transient absorption measurements. The regeneration of DPPBr and DPPCN2 by Co(III)(dtb)3 was instead inefficient, as most recombination for these dyes occurred on the sub-ns timescale. The transient spectroscopy data thus corroborated the trend of the published photovoltaic properties of dye-sensitized solar cells (DSSCs) based on these dyes on mesoporous NiO, and show the potential of a design strategy with a secondary acceptor bound to the dye. The study identifies rapid initial recombination between the dye and NiO as the main obstacle to obtaining high efficiencies in NiO-based DSSCs; these recombination components may be overlooked when studies are conducted using only methods with ns resolution or slower.

The application of sensitizers from red frangipani flowers and star gooseberry leaves in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Almaz Dhafina, Wan; Salleh, Hasiah; Zalani Daud, Muhamad; Ali, Nora’aini

2018-05-01

Nowadays natural based dyes for dye-sensitized solar cells (DSSCs) have been in research field attention due to its advantages over other type of dyes such as low-cost, low-toxicity, completely biodegradable and abundance of resources. Natural dyes can be produced via the simple extraction method of pigments from plant parts such as flower, fruits, leaves, tuber etc. In this feature article, the natural dyes which composed of anthocyanin pigment from red frangipani flowers and chlorophyll from star gooseberry leaves were applied in zinc oxide, (ZnO) based-DSSC. The ZnO photoanode of the DSSCs sample were sensitized in each dye with different duration. It was observed that DSSCs which has chlorophyll pigment as dye had better performance with power conversion efficiency (PCE) of 0.007%.

Effect of Mixing Dyes and Solvent in Electrolyte Toward Characterization of Dye Sensitized Solar Cell Using Natural Dyes as The Sensitizer

NASA Astrophysics Data System (ADS)

Puspitasari, Nurrisma; Nurul Amalia, Silviyanti S.; Yudoyono, Gatut; Endarko

2017-07-01

Dye Sensitized Solar Cell (DSSC) using natural dyes (chlorophyll, curcumin from turmeric extract, and anthocyanin from mangosteen extract) have been successfully fabricated for determining the effect of variation natural dyes, mixing dyes and acetonitrile in electrolyte toward characterization of DSSC. DSSC consists of five parts namely ITO (Indium Tin Oxide) as a substrate; TiO2 as semiconductor materials; natural dyes as an electron donor; electrolyte as electron transfer; and carbon as a catalyst that can convert light energy into electric energy. Two types of gel electrolyte based on PEG that mixed with liquid electrolyte have utilized for analyzing the lifetime of DSSC. Type I used distilled water as a solvent whilst type II used acetonitrile as a solvent with addition of concentration of KI and iodine. The main purpose of study was to investigate influence of solvent in electrolyte, variation of natural dyes and mixing dyes toward an efficiency that resulted by DSSC. The result showed that electrolyte type II is generally better than type I with efficiency 0,0556 and 0,0456 %, respectively. An efficiency values which resulted from a variation of mixed three natural dyes showed the greatest efficiency compared to mixed two natural dyes and one dye, with an efficiency value can be achieved at 0,0194 % for chlorophyll; 0,111 % for turmeric; 0,0105 % for mangosteen; 0,0244% (mangosteen and chlorophyll); 0,0117 % (turmeric and mangosteen); 0,0158 % (turmeric and chlorophyll); and 0.0566 % (mixed three natural dyes).

Effect of sintering time on the performance of turmeric dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Basuki, Hidajat, R. Lullus Lambang G.; Suyitno, Kristiawan, Budi; Rachmanto, Rendy Adhi

2017-01-01

This study reports the effect of sintering time on the performance of the dye-sensitized solar cells with turmeric dyes as sensitizers. Sintering TiO2 semiconductors were conducted at a temperature of 450°C for 30, 50, 90, 120, 150, and 180 minutes. The natural dye was extracted from dried turmeric powders with ethanol solvent. The results show that size of grains and the opening area of TiO2 semiconductor depended on the sintering time. The improvement of the properties of TiO2 semiconductor allowed more turmeric dyes were adsorbed by the semiconductors and then improved the performance of solar cells. The sintering time of 150 minutes produced large grains with an average diameter of 68.87 nm, and a porosity area of 26.51% caused the performance of DSSCs was the highest among other sintering time. The Voc, Jsc, and efficiency of DSSCs with turmeric-based natural dyes 0.64 V, 0.47 mA/cm2, and 0.2%, respectively.

Dye-sensitized solar cells based on purple corn sensitizers

NASA Astrophysics Data System (ADS)

Phinjaturus, Kawin; Maiaugree, Wasan; Suriharn, Bhalang; Pimanpaeng, Samuk; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan

2016-09-01

Natural dye extracted from husk, cob and silk of purple corn, were used for the first time as photosensitizers in dye sensitized solar cells (DSSCs). The dye sensitized solar cells fabrication process has been optimized in terms of solvent extraction. The resulting maximal efficiency of 1.06% was obtained from purple corn husk extracted by acetone. The ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and incident photon-to-current efficiency (IPCE) were employed to characterize the natural dye and the DSSCs.

Step-by-Step Heating of Dye Solution for Efficient Solar Energy Harvesting in Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Shah, Syed Afaq Ali; Sayyad, Muhammad Hassan; Abdulkarim, Salem; Qiao, Qiquan

2018-05-01

A step-by-step heat treatment was applied to ruthenium-based N719 dye solution for its potential application in dye-sensitized solar cells (DSSCs). The effects were analyzed and compared with standard untreated devices. A significant increase in short circuit current density was observed by employing a step-by-step heating method for dye solution in DSSCs. This increase of J sc is attributed to the enhancement in dye adsorption by the surface of the semiconductor and the higher number of charge carriers generated. DSSCs fabricated by a heated dye solution have achieved an overall power conversion efficiency of 8.41% which is significantly higher than the efficiency of 7.31% achieved with DSSCs fabricated without heated dye. Electrochemical impedance spectroscopy and capacitance voltage studies were performed to understand the better performance of the device fabricated with heated dye. Furthermore, transient photocurrent and transient photovoltage measurements were also performed to gain an insight into interfacial charge carrier recombinations.

Dye-sensitized solar cells using natural dyes as sensitizers from Malaysia local fruit `Buah Mertajam'

NASA Astrophysics Data System (ADS)

Hambali, N. A. M. Ahmad; Roshidah, N.; Hashim, M. Norhafiz; Mohamad, I. S.; Saad, N. Hidayah; Norizan, M. N.

2015-05-01

We experimentally demonstrate the high conversion efficiency, low cost, green technology and easy to fabricate dye-sensitized solar cells (DSSCs) using natural anthocyanin dyes as sensitizers. The DSSCs was fabricated by using natural anthocyanin dyes which were extracted from different parts of the plants inclusive `Buah Mertajam', `Buah Keriang Dot', `Bunga Geti', Hibiscus, Red Spinach and Henna. The natural anthocyanin dyes that found in flower, leaves and fruits were extracted by the simple procedures. This anthocyanin dye is used to replace the expensive chemical synthetic dyes due to its ability to effectively attach into the surface of Titanium dioxide (TiO2). A natural anthocyanin dyes molecule adsorbs to each particle of the TiO2 and acts as the absorber of the visible light. A natural anthocyanin dye from Buah Mertajam shows the best performance with the conversion efficiency of 5.948% and fill factor of 0.708 followed by natural anthocyanin dyes from `Buah Keriang Dot', `Bunga Geti', Hibiscus, Red Spinach and Henna. Buah Mertajam or scientifically known as eriglossum rubiginosum is a local Malaysia fruit.

Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices.

PubMed

Pati, Palas Baran; Zhang, Lei; Philippe, Bertrand; Fernández-Terán, Ricardo; Ahmadi, Sareh; Tian, Lei; Rensmo, Håkan; Hammarström, Leif; Tian, Haining

2017-06-09

A covalently linked organic dye-cobaloxime catalyst system based on mesoporous NiO is synthesized by a facile click reaction for mechanistic studies and application in a dye-sensitized solar fuel device. The system is systematically investigated by photoelectrochemical measurements, density functional theory, time-resolved fluorescence, transient absorption spectroscopy, and photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, the dye adopts different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst system on the photocathode is proposed on the basis of this study. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Photoanode Thickness Optimization and Impedance Spectroscopic Analysis of Dye-Sensitized Solar Cells based on a Carbazole-Containing Ruthenium Dye

NASA Astrophysics Data System (ADS)

Choi, Jongwan; Kim, Felix Sunjoo

2018-03-01

We studied the influence of photoanode thickness on the photovoltaic characteristics and impedance responses of the dye-sensitized solar cells based on a ruthenium dye containing a hexyloxyl-substituted carbazole unit (Ru-HCz). As the thickness of photoanode increases from 4.2 μm to 14.8 μm, the dye-loading amount and the efficiency increase. The device with thicker photoanode shows a decrease in the efficiency due to the higher probability of recombination of electron-hole pairs before charge extraction. We also analyzed the electron-transfer and recombination characteristics as a function of photoanode thickness through detailed electrochemical impedance spectroscopy analysis.

Theoretical studies on a new pattern of laser-driven systems: towards elucidation of direct photo-injection in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Mishima, Kenji; Yamashita, Koichi

2011-03-01

We theoretically and numerically investigated a new type of analytically solvable laser-driven systems inspired by electron-injection dynamics in dye-sensitized solar cells. The simple analytical expressions were found to be useful for understanding the difference between dye excitation and direct photo-injection occurring between dye molecule and semiconductor nanoparticles. More importantly, we propose a method for discriminating experimentally dye excitation and direct photo-injection by using time-dependent fluorescence. We found that dye excitation shows no significant quantum beat whereas the direct photo-injection shows a significant quantum beat. This work was supported by Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST) ``Development of Organic Photovoltaics toward a Low-Carbon Society,'' Cabinet Office, Japan.

Interplay between transparency and efficiency in dye sensitized solar cells.

PubMed

Tagliaferro, Roberto; Colonna, Daniele; Brown, Thomas M; Reale, Andrea; Di Carlo, Aldo

2013-02-11

In this paper we analyze the interplay between transparency and efficiency in dye sensitized solar cells by varying fabrication parameters such as the thickness of the nano-crystalline TiO(2) layer, the dye loading and the dye type. Both transparency and efficiency show a saturation trend when plotted versus dye loading. By introducing the transparency-efficiency plot, we show that the relation between transparency and efficiency is linear and is almost independent on the TiO(2) thickness for a certain thickness range. On the contrary, the relation between transparency and efficiency depends strongly on the type of the dye. Moreover, we show that co-sensitization techniques can be effectively used to access regions of the transparency-efficiency space that are forbidden for single dye sensitization. The relation found between transparency and efficiency (T&E) can be the general guide for optimization of Dye Solar Cells in building integration applications.

Higher Performance of DSSC with Dyes from Cladophora sp. as Mixed Cosensitizer through Synergistic Effect

PubMed Central

Haji Manaf, Noramaliyana; Tennakoon, Kushan; Chandrakanthi, R. L. N.; Lim, Linda Biaw Leng; Bandara, J. M. R. Sarath; Ekanayake, Piyasiri

2015-01-01

Chlorophyll and xanthophyll dyes extracted from a single source of filamentous freshwater green algae (Cladophora sp.) were used to sensitize dye sensitized solar cells and their performances were investigated. A more positive interaction is expected as the derived dyes come from a single natural source because they work mutually in nature. Cell sensitized with mixed chlorophyll and xanthophyll showed synergistic activity with improved cell performance of 1.5- to 2-fold higher than that sensitized with any individual dye. The effect of temperature and the stability of these dyes were also investigated. Xanthophyll dye was found to be more stable compared to chlorophyll that is attributed in the ability of xanthophyll to dissipate extra energy via reversible structural changes. Mixing the dyes resulted to an increase in effective electron life time and reduced the process of electron recombination during solar cell operation, hence exhibiting a synergistic effect. PMID:25688266

Higher Performance of DSSC with Dyes from Cladophora sp. as Mixed Cosensitizer through Synergistic Effect.

PubMed

Lim, Andery; Haji Manaf, Noramaliyana; Tennakoon, Kushan; Chandrakanthi, R L N; Lim, Linda Biaw Leng; Bandara, J M R Sarath; Ekanayake, Piyasiri

2015-01-01

Chlorophyll and xanthophyll dyes extracted from a single source of filamentous freshwater green algae (Cladophora sp.) were used to sensitize dye sensitized solar cells and their performances were investigated. A more positive interaction is expected as the derived dyes come from a single natural source because they work mutually in nature. Cell sensitized with mixed chlorophyll and xanthophyll showed synergistic activity with improved cell performance of 1.5- to 2-fold higher than that sensitized with any individual dye. The effect of temperature and the stability of these dyes were also investigated. Xanthophyll dye was found to be more stable compared to chlorophyll that is attributed in the ability of xanthophyll to dissipate extra energy via reversible structural changes. Mixing the dyes resulted to an increase in effective electron life time and reduced the process of electron recombination during solar cell operation, hence exhibiting a synergistic effect.

Extension lifetime for dye-sensitized solar cells through multiple dye adsorption/desorption process

NASA Astrophysics Data System (ADS)

Chiang, Yi-Fang; Chen, Ruei-Tang; Shen, Po-Shen; Chen, Peter; Guo, Tzung-Fang

2013-03-01

In this study, we propose a novel concept of extending the lifetime of dye-sensitized solar cells (DSCs) and reducing the costs of re-conditioning DSCs by recycling the FTO/TiO2 substrates. The photovoltaic performances of DSCs using substrates with various cycles of dye uptake and rinse off history are tested. The results show that dye adsorption and Voc are significantly increased under multiple dye adsorption/desorption process and resulted in the improvement of power conversion efficiency. Moreover, the dyeing kinetics is faster after multiple recycling processes, which is favorable for the industrial application. With surface analysis and charge transport characteristics, we also demonstrate the optimal functionality of TiO2/dye interface for the improved Voc and efficiency. The results confirm that the improved performances are due to increased dye loading and dense packing of dye molecules. Our results are beneficial for the understanding on the extension of DSCs lifetime after long-term operation in the application of DSC modules. This approach may also be applied in the replacement of newly synthesized photosensitizes to the active cells.

Effect of acidity on the energy level of curcumin dye extracted from Curcuma longa L.

NASA Astrophysics Data System (ADS)

Agustia, Yuda Virgantara; Suyitno, Arifin, Zainal; Sutanto, Bayu

2016-03-01

The purpose of this research is to investigate the effect of acidity on the energy level of curcumin dye. The natural dye, curcumin, was synthesized from Curcuma longa L. using a simple extraction technique. The purification of curcumin dye was conducted in a column of chromatography and its characteristics were studied. Next, the purified curcumin dye was added by benzoic acids until various acidities of 3.0, 3.5, 4.0, 4.5, and 5.0. The absorbance spectra and the functionality groups found in the dyes were detected by ultraviolet-visible spectroscopy and Fourier-transform infrared spectroscopy, respectively. Meanwhile, the energy level of the dyes, EHOMO and ELUMO was measured by cyclic voltammetry. The best energy level of curcumin dye was achieved at pH 3.5 where Ered = -0.37V, ELUMO = -4.28 eV, Eox = 1.15V, EHOMO = -5.83 eV, and Eband gap = 1.55 eV. Therefore, the purified curcumin dye added by benzoic acid was promising for sensitizing the dye-sensitized solar cells.

Efficient iodine-free dye-sensitized solar cells employing truxene-based organic dyes.

PubMed

Zong, Xueping; Liang, Mao; Chen, Tao; Jia, Jiangnan; Wang, Lina; Sun, Zhe; Xue, Song

2012-07-07

Two new truxene-based organic sensitizers (M15 and M16) featuring high extinction coefficients were synthesized for dye-sensitized solar cells employing cobalt electrolyte. The M16-sensitized device displays a 7.6% efficiency at an irradiation of AM1.5 full sunlight.

Light harvesting over a wide range of wavelength using natural dyes of gardenia and cochineal for dye-sensitized solar cells.

PubMed

Park, Kyung-Hee; Kim, Tae-Young; Han, Shin; Ko, Hyun-Seok; Lee, Suk-Ho; Song, Yong-Min; Kim, Jung-Hun; Lee, Jae-Wook

2014-07-15

Two natural dyes extracted from gardenia yellow (Gardenia jasminoides) and cochineal (Dactylopius coccus) were used as sensitizers in the assembly of dye-sensitized solar cells (DSSCs) to harvest light over a wide range of wavelengths. The adsorption characteristics, electrochemical properties and photovoltaic efficiencies of the natural DSSCs were investigated. The adsorption kinetics data of the dyes were obtained in a small adsorption chamber and fitted with a pseudo-second-order model. The photovoltaic performance of a photo-electrode adsorbed with single-dye (gardenia or cochineal) or the mixture or successive adsorption of the two dyes, was evaluated from current-voltage measurements. The energy conversion efficiency of the TiO2 electrode with the successive adsorption of cochineal and gardenia dyes was 0.48%, which was enhanced compared to single-dye adsorption. Overall, a double layer of the two natural dyes as sensitizers was successfully formulated on the nanoporous TiO2 surface based on the differences in their adsorption affinities of gardenia and cochineal. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of Donor Strength and Bulk on Thieno[3,4-b]-pyrazine-Based Panchromatic Dyes in Dye-Sensitized Solar Cells.

PubMed

Liyanage, Nalaka P; Cheema, Hammad; Baumann, Alexandra R; Zylstra, Alexa R; Delcamp, Jared H

2017-06-22

Near-infrared-absorbing organic dyes are critically needed in dye-sensitized solar cells (DSCs). Thieno[3,4-b]pyrazine (TPz) based dyes can access the NIR spectral region and show power conversion efficiencies (PCEs) of up to 8.1 % with sunlight being converted at wavelengths up to 800 nm for 17.6 mA cm -2 of photocurrent in a co-sensitized DSC device. Precisely controlling dye excited-state energies is critical for good performances in NIR DSCs. Strategies to control TPz dye energetics with stronger donor groups and TPz substituent choice are evaluated here. Additionally, donor size influence versus dye loading on TPz dyes is analyzed with respect to the TiO 2 surface protection designed to prevent recombination of electrons in TiO 2 with the redox shuttle. Importantly, the dyes evaluated were demonstrated to work well with low Li + concentration electrolytes, with iodine and cobalt redox shuttle systems, and efficiently as part of co-sensitized devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hair dye dermatitis and p-phenylenediamine contact sensitivity: A preliminary report

PubMed Central

Gupta, Mrinal; Mahajan, Vikram K.; Mehta, Karaninder S.; Chauhan, Pushpinder S.

2015-01-01

Background: The contact allergic reactions from p-phenylenediamine (PPD) in hair dyes vary from mild contact dermatitis to severe life- threatening events (angioedema, bronchospasm, asthma, renal impairment). Objectives: To study the clinical patterns and PPD contact sensitivity in patients with hair-dye dermatitis. Materials and Methods: Eighty (M:F 47:33) consecutive patients aged between 18 and 74 years suspected to have contact allergy from hair dye were studied by patch testing with Indian Standard Series including p-phenylenediamine (PPD, 1.0% pet). Results: 54 Fifty-four (M:F 21:33) patients showed positive patch tests from PPD. Eight of these patients also showed positive patch test reaction from fragrance mix, thiuram mix, paraben mix, or colophony. Fifty-seven (71%) patients affected were aged older than 40 years. The duration of dermatitis varied from < 1 month to > 1 year with exacerbation following hair coloring. Forty-nine patients had dermatitis of scalp and/or scalp margins and 23 patients had face and neck dermatitis. Periorbital dermatitis, chronic actinic dermatitis, and erythema multiforme-like lesions were seen in 4, 2, and 1 patients, respectively. Conclusions: Hair dyes and PPD constitute a significant cause of contact dermatitis. There is an urgent need for creating consumer awareness regarding hair-dyes contact sensitivity and the significance of performing sensitivity testing prior to actual use. PMID:26225326

Effect of Molecular Coupling on Ultrafast Electron-Transfer and Charge-Recombination Dynamics in a Wide-Gap ZnS Nanoaggregate Sensitized by Triphenyl Methane Dyes.

PubMed

Debnath, Tushar; Maity, Partha; Dana, Jayanta; Ghosh, Hirendra N

2016-03-03

Wide-band-gap ZnS nanocrystals (NCs) were synthesized, and after sensitizing the NCs with series of triphenyl methane (TPM) dyes, ultrafast charge-transfer dynamics was demonstrated. HRTEM images of ZnS NCs show the formation of aggregate crystals with a flower-like structure. Exciton absorption and lumimescence, due to quantum confinement of the ZnS NCs, appear at approximately 310 and 340 nm, respectively. Interestingly, all the TPM dyes (pyrogallol red, bromopyrogallol red, and aurin tricarboxylic acid) form charge-transfer complexes with the ZnS NCs, with the appearance of a red-shifted band. Electron injection from the photoexcited TPM dyes into the conduction band of the ZnS NCs is shown to be a thermodynamically viable process, as confirmed by steady-state and time-resolved emission studies. To unravel charge-transfer (both electron injection and charge recombination) dynamics and the effect of molecular coupling, femtosecond transient absorption studies were carried out in TPM-sensitized ZnS NCs. The electron-injection dynamics is pulse-width-limited in all the ZnS/TPM dye systems, however, the back electron transfer differs, depending on the molecular coupling of the sensitizers (TPM dyes). The detailed mechanisms for the above-mentioned processes are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multilayer Dye Aggregation at Dye/TiO2 Interface via π…π Stacking and Hydrogen Bond and Its Impact on Solar Cell Performance: A DFT Analysis.

PubMed

Zhang, Lei; Liu, Xiaogang; Rao, Weifeng; Li, Jingfa

2016-10-21

Multilayer dye aggregation at the dye/TiO 2 interface of dye-sensitized solar cells is probed via first principles calculations, using p-methyl red azo dye as an example. Our calculations suggest that the multilayer dye aggregates at the TiO 2 surface can be stabilized by π…π stacking and hydrogen bond interactions. Compared with previous two-dimensional monolayer dye/TiO 2 model, the multilayer dye aggregation model proposed in this study constructs a three-dimensional multilayer dye/TiO 2 interfacial structure, and provides a better agreement between experimental and computational results in dye coverage and dye adsorption energy. In particular, a dimer forms by π…π stacking interactions between two neighboring azo molecules, while one of them chemisorbs on the TiO 2 surface; a trimer may form by introducing one additional azo molecule on the dimer through a hydrogen bond between two carboxylic acid groups. Different forms of multilayer dye aggregates, either stabilized by π…π stacking or hydrogen bond, exhibit varied optical absorption spectra and electronic properties. Such variations could have a critical impact on the performance of dye sensitized solar cells.

Multilayer Dye Aggregation at Dye/TiO2 Interface via π…π Stacking and Hydrogen Bond and Its Impact on Solar Cell Performance: A DFT Analysis

PubMed Central

Zhang, Lei; Liu, Xiaogang; Rao, Weifeng; Li, Jingfa

2016-01-01

Multilayer dye aggregation at the dye/TiO2 interface of dye-sensitized solar cells is probed via first principles calculations, using p-methyl red azo dye as an example. Our calculations suggest that the multilayer dye aggregates at the TiO2 surface can be stabilized by π…π stacking and hydrogen bond interactions. Compared with previous two-dimensional monolayer dye/TiO2 model, the multilayer dye aggregation model proposed in this study constructs a three-dimensional multilayer dye/TiO2 interfacial structure, and provides a better agreement between experimental and computational results in dye coverage and dye adsorption energy. In particular, a dimer forms by π…π stacking interactions between two neighboring azo molecules, while one of them chemisorbs on the TiO2 surface; a trimer may form by introducing one additional azo molecule on the dimer through a hydrogen bond between two carboxylic acid groups. Different forms of multilayer dye aggregates, either stabilized by π…π stacking or hydrogen bond, exhibit varied optical absorption spectra and electronic properties. Such variations could have a critical impact on the performance of dye sensitized solar cells. PMID:27767196

Characterization of screen-printed dye-sensitized nanocrystalline TiO2 solar cells

NASA Astrophysics Data System (ADS)

Gupta, Tapan K.; Cirignano, Leonard J.; Shah, Kanai S.; Moy, Larry P.; Kelly, David J.; Squillante, Michael R.; Entine, Gerald; Smestad, Greg P.

1999-10-01

Titanium dioxide (TiO2) films have been deposited on SnO2 coated glass substrates by screen-printing. Film morphology and structure have been characterized by scanning electron microscopy, x-ray diffraction and BET analysis. Dye-sensitized TiO2 photoelectrochemical cells have been assembled and characterized. Cells sensitized with anthocyanin and a ruthenium complex have been investigated. A 0.77 cm2 ruthenium dye sensitized cell with 6.1% power conversion efficiency under Air Mass (AM1.5) conditions was obtained. Results obtained with a pure anthocyanin dye and dye extracted from blackberries were compared. Finally, a natural gel was found to improve the stability of anthocyanin sensitized cells.

Study of TiO2 particles size, dyes, and catalyst to improve the performance of DSSC

NASA Astrophysics Data System (ADS)

Saehana, Sahrul; Darsikin, Muslimin

2016-02-01

This study reports effort to improve performance of solar cells by using various natural dyes in dye-sensitized solar cell (DSSC). We applied three kind of natural dye, i.e, black rice dye, cactus dye and dragon fruit dye. We found that performance of DSSC which employ black rice dye was higher than other natural dyes. It is because the wider spectrum wavelength of black rice dyes. Its performance also compared with rhutenium dye (N719). Effect of TiO2 particle to DSSC performance was also investigated. It was concluded that smaller TiO2 particle size will increase the performance of DSSC solar cells. It was because the smaller particle size (high surface area) will load more dye. In addition, we also demonstrated the use of graphite from lead pencil as counter electrode.

Electrical characterization of dye sensitized nano solar cell using natural pomegranate juice as photosensitizer

NASA Astrophysics Data System (ADS)

Adithi, U.; Thomas, Sara; Uma, V.; Pradeep, N.

2013-02-01

This paper shows Electrical characterization of Dye Sensitized Solar Cell using natural dye, extracted from the pomegranate as a photo sensitizer and ZnO nanoparticles as semiconductor. The constituents of fabricated dye sensitized solar cell were working electrode, dye, electrolyte and counter electrode. ZnO nanoparticles were synthesized and used as semiconductor in working electrode. Carbon soot was used as counter electrode. The resistance of ZnO film on ITO film was found out. There was an increase in the resistance of the film and film changes from conducting to semiconducting. Photovoltaic parameters of the fabricated cell like Short circuit current, open circuit voltage, Fill factor and Efficiency were found out. This paper shows that usage of natural dyes like pomegranate juice as sensitizer enables faster and simpler production of cheaper and environmental friendly solar cell.

Photoelectric characterization of fabricated dye-sensitized solar cell using dye extracted from red Siahkooti fruit as natural sensitizer

NASA Astrophysics Data System (ADS)

Mozaffari, Sayed Ahmad; Saeidi, Mahsa; Rahmanian, Reza

2015-05-01

Natural dye extracted from Siahkooti fruit with/without purification by solid phase extraction (SPE) technique was used in the fabrication of DSSC as natural sensitizer. The UV-Vis absorption spectroscopy and Fourier transform infrared (FTIR) were employed to indicate the presence of anthocyanins in the fruit of red Siahkooti. The photoelectrochemical performance and the efficiency of assembled DSSC using Siahkooti fruit dye extract were evaluated and efficiency enhancement was obtained by a preliminary purification of extracted dye. The efficiency and fill factor of the DSSC using purified Siahkooti fruit dye were 0.32% and 0.73%, respectively. The results successfully showed that the DSSC, using Siahkooti fruit extract as a dye sensitizer, is useful for the preparation of environmentally friendly, low-cost, renewable and clean sources of energy.

Organic photosensitizers with a heteroleptic dual donor for dye-sensitized solar cells.

PubMed

Kim, Joo Young; Kim, Young Sik

2012-04-01

Using DFT and TDDFT calculations, we investigated the substitution effect in the electronic and optical properties of dye sensitizers with a dual donor composed of triphenylamine and/or indoline moieties. Due to replacement with the dual donor moieties, the HOMO levels were split into HOMO and HOMO - 1 levels, and the bandgaps between the HOMO and LUMO levels decreased, leading to the creation of bathochromically extended absorption spectra. Nearly degenerated splitting of the HOMO levels resulted from the similarity of the electronic structure between the HOMO and the HOMO - 1 levels, delocalized over both dual-donor moieties, when replacing the dual donors. It was shown that the additional electron-donating group creates an additional absorption band and causes a cascading two-electron process aiding the charge separation process. Owing to a more panchromatic attribute, easier energy transfer and feasible retardation of the recombination between the injected electrons and the electrolyte, it is expected that dyeTI will show better performance than the other dyes (dyeT dyeTT and dyeIT) as denoted here in terms of the conversion efficiency of dye-sensitized solar cells (DSSCs). This work presents the probable benefits of dye sensitizers with dual-donor moieties and provides insight into the development of more efficient dye sensitizers for DSSCs through modification of the Frontier molecular orbitals.

Iodinated Al(III)-based phthalocyanines are promising sensitizers for dye-sensitized solar cells; a theoretical comparison between Zn(II), Mg(II), and Al(III)-based phthalocyanine sensitizers.

PubMed

Yang, Li-Na; Sun, Zhu-Zhu; Chen, Shi-Lu; Li, Ze-Sheng

2014-02-24

To design efficient dyes for dye-sensitized solar cells (DSSCs), using a Zn-coordinated phthalocyanine (TT7) as the prototype, a series of phthalocyanine dyes (Pcs) with different metal ions and peripheral/axial groups have been investigated by means of density functional theory (DFT) and time-dependent DFT (TDDFT) methods. Computational results show that the iodinated Al-based dye with a peripheral amino group (Al-I-NH2-Pc) exhibits the largest redshift in the maximum absorbance (λ(max)). In addition, Al-based dyes have appropriate energy-level arrangements of frontier orbitals to keep excellent balance between electron injection and regeneration of oxidized dyes. Further, it has been found that the intermolecular π-staking interaction in Al-I-Pc molecules is weaker than the other metal-based Pcs, which may effectively reduce dye aggregation on the semi-conductor surface. All these results suggest iodinated Al-based Pcs (Al-I-Pcs) to be potentially promising sensitizers in DSSCs. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The dye-sensitized solar cell database.

PubMed

Venkatraman, Vishwesh; Raju, Rajesh; Oikonomopoulos, Solon P; Alsberg, Bjørn K

2018-04-03

Dye-sensitized solar cells (DSSCs) have garnered a lot of attention in recent years. The solar energy to power conversion efficiency of a DSSC is influenced by various components of the cell such as the dye, electrolyte, electrodes and additives among others leading to varying experimental configurations. A large number of metal-based and metal-free dye sensitizers have now been reported and tools using such data to indicate new directions for design and development are on the rise. DSSCDB, the first of its kind dye-sensitized solar cell database, aims to provide users with up-to-date information from publications on the molecular structures of the dyes, experimental details and reported measurements (efficiencies and spectral properties) and thereby facilitate a comprehensive and critical evaluation of the data. Currently, the DSSCDB contains over 4000 experimental observations spanning multiple dye classes such as triphenylamines, carbazoles, coumarins, phenothiazines, ruthenium and porphyrins. The DSSCDB offers a web-based, comprehensive source of property data for dye sensitized solar cells. Access to the database is available through the following URL: www.dyedb.com .

The influence of the distance between the donor-acceptor groups of polymethine dyes on their photovoltaic properties

NASA Astrophysics Data System (ADS)

Seliverstova, E.; Ibrayev, N.

2018-01-01

Spectral-luminescent and photovoltaic properties of polymethine dyes of various structures are studied. It is shown that an increase in the length of the methylene chain between the active chromophores leads to a red-wave shift of the absorption and fluorescence spectra. Significant changes in the absorptivity and lifetime of fluorescence do not occur in this case. The best photovoltaic parameters have cells sensitized with shorter dye molecules. It is shown, that for a longer dye the resistance associated with electron recombination on the TiO2/electrolyte surface is much higher than the electron transfer resistance in the semiconductor, which reduces the efficiency of electron transfer in the solar cell, sensitized with longer dye molecules.

Broadband energy transfer to sensitizing dyes by mobile quantum dot mediators in solar cells

PubMed Central

Adhyaksa, Gede Widia Pratama; Lee, Ga In; Baek, Se-Woong; Lee, Jung-Yong; Kang, Jeung Ku

2013-01-01

The efficiency of solar cells depends on absorption intensity of the photon collectors. Herein, mobile quantum dots (QDs) functionalized with thiol ligands in electrolyte are utilized into dye–sensitized solar cells. The QDs serve as mediators to receive and re–transmit energy to sensitized dyes, thus amplifying photon collection of sensitizing dyes in the visible range and enabling up–conversion of low-energy photons to higher-energy photons for dye absorption. The cell efficiency is boosted by dispersing QDs in electrolyte, thereby obviating the need for light scattering1 or plasmonic2 structures. Furthermore, optical spectroscopy and external quantum efficiency data reveal that resonance energy transfer due to the overlap between QD emission and dye absorption spectra becomes dominant when the QD bandgap is higher than the first excitonic peak of the dye, while co–sensitization resulting in a fast reduction of oxidized dyes is pronounced in the case of lower QD band gaps. PMID:24048384

A Titanium Oxo Cluster Model Study of Synergistic Effect of Co-coordinated Dye Ligands on Photocurrent Responses.

PubMed

Hou, Jin-Le; Huo, Peng; Tang, Zheng-Zhen; Cui, Li-Na; Zhu, Qin-Yu; Dai, Jie

2018-05-24

The use of multiple sensitizers in dye sensitized solar cells has been attractive as a promising way to achieve highly efficient photovoltaic performance. However, except for the complementary absorption, synergistic effects among the dye components have not been well understood. Herein, using ferrocene-1-carboxylate (FcCO 2 ) and catechol (Cat) as dye ligands, two titanium oxo clusters (TOCs), [Ti 3 O(O i Pr) 6 (Cat)(FcCO 2 ) 2 ] (1) and [Ti 7 O 4 (O i Pr) 8 (Cat) 5 (FcCO 2 ) 2 ] (2), were synthesized and structurally characterized. Another TOC, [Ti 7 O 3 (O i Pr) 12 (Cat) 4 ( o-BDC)] (3) ( o-BDC = o-benzene dicarboxylate), was also prepared as a contrast. Electronic spectra and theoretical calculations showed that charge transfer occurs from ligands FcCO 2 and Cat to the TiO cluster core and the contribution of redox active FcCO 2 is greater than that of Cat. Using the clusters as TiO-dye pre-anchored precursors, multi-dye sensitized TiO 2 electrodes were prepared. Although the two dyes FcCO 2 and Cat do not complement each other in spectra, a synergistic effect on the enhancement of photocurrent responses was found and discussed in view of the inter-dyes electron communication.

Study of chemical reactivity in relation to experimental parameters of efficiency in coumarin derivatives for dye sensitized solar cells using DFT.

PubMed

Soto-Rojo, Rody; Baldenebro-López, Jesús; Glossman-Mitnik, Daniel

2015-06-07

A group of dyes derived from coumarin was studied, which consisted of nine molecules using a very similar manufacturing process of dye sensitized solar cells (DSSCs). Optimized geometries, energy levels of the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and ultraviolet-visible spectra were obtained using theoretical calculations, and they were also compared with experimental conversion efficiencies of the DSSC. The representation of an excited state in terms of natural transition orbitals (NTOs) was studied. Chemical reactivity parameters were calculated and correlated with the experimental data linked to the efficiency of the DSSC. A new proposal was obtained to design new molecular systems and to predict their potential use as a dye in DSSCs.

Co-sensitization of ruthenium(II) dye-sensitized solar cells by coumarin based dyes

NASA Astrophysics Data System (ADS)

Athanas, Anish Babu; Thangaraj, Shankar; Kalaiyar, Swarnalatha

2018-05-01

Co-sensitization technique has been appraised for attaining enhanced performance in dye-sensitized solar cells (DSSCs). DSSCs are fabricated with a heteroleptic Ru(II) sensitizer (RDAB1) containing 4,4‧-diamino-2,2‧-bipyridine (dabpy) ligand, co-sensitized with electron donor-acceptor type coumarin containing thiophene (CT) and indole (CI) moieties. The individual overall power conversion efficiency of the sensitizer is 5.44%. Enhanced power conversion efficiencies of 6.34% and 7.09% were observed when RDAB1 was co-sensitized with Coumarin containing CI and CT respectively. The enhanced PCE can be attributed to the presence of co-sensitizers which effectively overcome the light absorption by I-/I3-, dye aggregation and charge recombination.

Acene-modified triphenylamine dyes for dye-sensitized solar cells: a computational study.

PubMed

Fan, Wenjie; Tan, Dazhi; Deng, Wei-Qiao

2012-06-04

A series of metal-free acene-modified triphenylamine dyes (benzene to pentacene, denoted as TPA-AC1 to TPA-AC5) are investigated as organic sensitizers for application in dye-sensitized solar cells (DSSCs). A combination of density functional theory (DFT), density functional tight-binding (DFTB), and time-dependent DFT (TDDFT) approaches is employed. The effects of acene units on the spectra and electrochemical properties of the acene-modified TPA organic dyes are demonstrated. The dye/(TiO(2))(46) anatase nanoparticle systems are also simulated to show the electronic structures at the interface. The results show that from TPA-AC1 to TPA-AC5 with increasing sizes of the acenes, the absorption and fluorescence spectra are systematically broadened and red-shifted, but the oscillator strength and electron injection properties are reduced. The molecular orbital contributions show increasing localization on the bridging acene units from TPA-AC1 to TPA-AC5. From the theoretical examination of some key parameters including free enthalpy related to the electron injection, light-harvesting efficiency, and the shift of semiconductor conduction band, TPA-AC3 with an anthracene moiety demonstrates a balance of the above crucial factors. TPA-AC3 is expected to be a promising dye with desirable energetic and spectroscopic parameters in the DSSC field, which is consistent with recent experimental work. This study is expected to deepen our understanding of TPA-based organic dyes and assist the molecular design of new metal-free dyes for the further optimization of DSSCs. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The influence of local electric fields on photoinduced absorption in dye-sensitized solar cells.

PubMed

Cappel, Ute B; Feldt, Sandra M; Schöneboom, Jan; Hagfeldt, Anders; Boschloo, Gerrit

2010-07-07

The dye-sensitized solar cell (DSC) challenges conventional photovoltaics with its potential for low-cost production and its flexibility in terms of color and design. Transient absorption spectroscopy is widely used to unravel the working mechanism of DSCs. A surprising, unexplained feature observed in these studies is an apparent bleach of the ground-state absorption of the dye, under conditions where the dye is in the ground state. Here, we demonstrate that this feature can be attributed to a change of the local electric field affecting the absorption spectrum of the dye, an effect related to the Stark effect first reported in 1913. We present a method for measuring the effect of an externally applied electric field on the absorption of dye monolayers adsorbed on flat TiO(2) substrates. The measured signal has the shape of the first derivative of the absorption spectra of the dyes and reverses sign along with the reversion of the direction of the change in dipole moment upon excitation relative to the TiO(2) surface. A very similar signal is observed in photoinduced absorption spectra of dye-sensitized TiO(2) electrodes under solar cell conditions, demonstrating that the electric field across the dye molecules changes upon illumination. This result has important implications for the analysis of transient absorption spectra of DSCs and other molecular optoelectronic devices and challenges the interpretation of many previously published results.

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

DOE PAGES

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

2016-01-06

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

Theoretical Study of Ultrafast Electron Injection into a Dye/TiO2 System in Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Lin, Chundan; Xia, Qide; Li, Kuan; Li, Juan; Yang, Zhenqing

2018-06-01

The ultrafast injection of excited electrons in dye/TiO2 system plays a critical role, which determines the device's efficiency in large part. In this work, we studied the geometrical structures and electronic properties of a dye/TiO2 composite system for dye-sensitized solar cells (DSSCs) by using density functional theory, and we analyzed the mechanism of ultrafast electron injection with emphasis on the power conversion efficiency. The results show that the dye SPL103/TiO2 (101) surface is more stable than dye SPL101. The electron injection driving force of SPL103/TiO2 (101) is 3.55 times that of SPL101, indicating that SPL103/TiO2 (101) has a strong ability to transfer electrons. SPL103 and SPL101/TiO2 (101) both have fast electron transfer processes, and especially the electron injection time of SPL103/TiO2 (101) is only 1.875 fs. The results of this work are expected to provide a new understanding of the mechanism of electron injection in dyes/TiO2 systems for use in highly effective DSSCs.

Photoelectric characterization of fabricated dye-sensitized solar cell using dye extracted from red Siahkooti fruit as natural sensitizer.

PubMed

Mozaffari, Sayed Ahmad; Saeidi, Mahsa; Rahmanian, Reza

2015-05-05

Natural dye extracted from Siahkooti fruit with/without purification by solid phase extraction (SPE) technique was used in the fabrication of DSSC as natural sensitizer. The UV-Vis absorption spectroscopy and Fourier transform infrared (FTIR) were employed to indicate the presence of anthocyanins in the fruit of red Siahkooti. The photoelectrochemical performance and the efficiency of assembled DSSC using Siahkooti fruit dye extract were evaluated and efficiency enhancement was obtained by a preliminary purification of extracted dye. The efficiency and fill factor of the DSSC using purified Siahkooti fruit dye were 0.32% and 0.73%, respectively. The results successfully showed that the DSSC, using Siahkooti fruit extract as a dye sensitizer, is useful for the preparation of environmentally friendly, low-cost, renewable and clean sources of energy. Copyright © 2015 Elsevier B.V. All rights reserved.

A Triphenylamine-Based Conjugated Polymer with Donor-π-Acceptor Architecture as Organic Sensitizer for Dye-Sensitized Solar Cells.

PubMed

Zhang, Wei; Fang, Zhen; Su, Mingjuan; Saeys, Mark; Liu, Bin

2009-09-17

A conjugated polymer containing an electron donating backbone (triphenylamine) and an electron accepting side chain (cyanoacetic acid) with conjugated thiophene units as the linkers has been synthesized. Dye-sensitized solar cells (DSSCs) are fabricated utilizing this material as the dye sensitizer, resulting a typical power conversion efficiency of 3.39% under AM 1.5 G illumination, which represents the highest efficiency for polymer dye-sensitized DSSCs reported so far. The results show the good promise of conjugated polymers as sensitizers for DSSC applications. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Near-infrared absorbing squarylium dyes with linearly extended π-conjugated structure for dye-sensitized solar cell applications.

PubMed

Maeda, Takeshi; Hamamura, Yuuto; Miyanaga, Kyohei; Shima, Naoki; Yagi, Shigeyuki; Nakazumi, Hiroyuki

2011-11-18

A novel class of near-infrared absorbing squarylium sensitizers with linearly extended π-conjugated structures, which were obtained by Pd-catalyzed cross-coupling reactions with stannylcyclobutenediones, has been developed for dye-sensitized solar cells. The cells based on these dyes exhibited a significant spectral response in the near-infrared region over 750 nm in addition to the visible region.

Precise identification and manipulation of adsorption geometry of donor-π-acceptor dye on nanocrystalline TiO₂ films for improved photovoltaics.

PubMed

Zhang, Fan; Ma, Wei; Jiao, Yang; Wang, Jingchuan; Shan, Xinyan; Li, Hui; Lu, Xinghua; Meng, Sheng

2014-12-24

Adsorption geometry of dye molecules on nanocrystalline TiO2 plays a central role in dye-sensitized solar cells, enabling effective sunlight absorption, fast electron injection, optimized interface band offsets, and stable photovoltaic performance. However, precise determination of dye binding geometry and proportion has been challenging due to complexity and sensitivity at interfaces. Here employing combined vibrational spectrometry and density functional calculations, we identify typical adsorption configurations of widely adopted cyanoacrylic donor-π bridge-acceptor dyes on nanocrystalline TiO2. Binding mode switching from bidentate bridging to hydrogen-bonded monodentate configuration with Ti-N bonding has been observed when dye-sensitizing solution becomes more basic. Raman and infrared spectroscopy measurements confirm this configuration switch and determine quantitatively the proportion of competing binding geometries, with vibration peaks assigned using density functional theory calculations. We further found that the proportion of dye-binding configurations can be manipulated by adjusting pH value of dye-sensitizing solutions. Controlling molecular adsorption density and configurations led to enhanced energy conversion efficiency from 2.4% to 6.1% for the fabricated dye-sensitized solar cells, providing a simple method to improve photovoltaic performance by suppressing unfavorable binding configurations in solar cell applications.

Dye sensitized solar cell (DSSC) with natural dyes extracted from Jatropha leaves and purple Chrysanthemum flowers as sensitizer

NASA Astrophysics Data System (ADS)

Tahir, Dahlang; Satriani, Wilda; Gareso, P. L.; Abdullah, B.

2018-03-01

DSSC (Dye-Sensitized Solar Cell) prototype has been investigated using Jatropha leaves and purple Chrysanthemum flowers as natural dyes. DSSC consists of working electrode and counter electrode. A working electrode composed of semiconductor nanoparticles TiO2 that has been coated with dye molecules. Dye molecules serve as light photon catchers, while semiconductor nanoparticles TiO2 function to absorb and forward photons into electrons. In the electrode counter given catalyst carbon, serves to accelerate the reaction kinetics of triiodide reduction process on transparent conductive oxide (TCO). DSSC using TiO2 as a semiconductor material and natural dyes as sensitizer from Jatropha leaves and purple Chrysanthemum flowers are successful produced. The physical properties of the working electrode have been determined by using XRD and the chemical properties of the TiO2 powder and dye powder using FTIR and dye solution using UV-Vis. The resulted fabrications are also examined its I-V characteristics. The best performance is generated by mixed dye 1.91 x 10-3 % compared than those DSSC for dye extracted from Jatropha leaves or purple Chrysanthemum. The characterization results show that the higher of the absorption wavelength of the DSSC efficiency is high.

Effect of acidity on the energy level of curcumin dye extracted from Curcuma longa L

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

Agustia, Yuda Virgantara, E-mail: yuda.mechanical.engineer@student.uns.ac.id; Suyitno,, E-mail: suyitno@uns.ac.id; Sutanto, Bayu, E-mail: bayu.sutanto@student.uns.ac.id

2016-03-29

The purpose of this research is to investigate the effect of acidity on the energy level of curcumin dye. The natural dye, curcumin, was synthesized from Curcuma longa L. using a simple extraction technique. The purification of curcumin dye was conducted in a column of chromatography and its characteristics were studied. Next, the purified curcumin dye was added by benzoic acids until various acidities of 3.0, 3.5, 4.0, 4.5, and 5.0. The absorbance spectra and the functionality groups found in the dyes were detected by ultraviolet-visible spectroscopy and Fourier-transform infrared spectroscopy, respectively. Meanwhile, the energy level of the dyes, E{submore » HOMO} and E{sub LUMO} was measured by cyclic voltammetry. The best energy level of curcumin dye was achieved at pH 3.5 where E{sub red} = −0.37V, E{sub LUMO} = −4.28 eV, E{sub ox} = 1.15V, E{sub HOMO} = −5.83 eV, and E{sub band} {sub gap} = 1.55 eV. Therefore, the purified curcumin dye added by benzoic acid was promising for sensitizing the dye-sensitized solar cells.« less

Dye-sensitization of CdS nano-cage - A density functional theory approach

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

Jain, Kalpna; Singh, Kh. S.; Kishor, Shyam

2016-05-23

Quantum dots a few nanometer in size exhibit unique properties in comparison to bulk due to quantum confinement. Their properties can be tuned according to their sizes. Dye sensitized quantum dot (DSQD) solar cells are based on the same principle with surface dangling bonds as a challenge. Researches have shown the existence and stability of nano-cages which are assembled such as to minimize the surface dangling bonds and hence maximize stability. Here, we report a first principles DFT study of optical and electronic properties of CdS-cage (Cd{sub 34}S{sub 34}) sensitized with nkx-2388 dye in three different geometric configurations of dyemore » attachment. A significant distortion is found to occur in the geometric structure of the cage when it interacts strongly with the dye. The relative positioning of dye and cage energy levels is found to be different in different configurations. The absorption spectrum has been analyzed with the help of natural transition orbitals (NTO).« less

Near-infrared voltage-sensitive fluorescent dyes optimized for optical mapping in blood-perfused myocardium.

PubMed

Matiukas, Arvydas; Mitrea, Bogdan G; Qin, Maochun; Pertsov, Arkady M; Shvedko, Alexander G; Warren, Mark D; Zaitsev, Alexey V; Wuskell, Joseph P; Wei, Mei-de; Watras, James; Loew, Leslie M

2007-11-01

Styryl voltage-sensitive dyes (e.g., di-4-ANEPPS) have been used successfully for optical mapping in cardiac cells and tissues. However, their utility for probing electrical activity deep inside the myocardial wall and in blood-perfused myocardium has been limited because of light scattering and high absorption by endogenous chromophores and hemoglobin at blue-green excitation wavelengths. The purpose of this study was to characterize two new styryl dyes--di-4-ANBDQPQ (JPW-6003) and di-4-ANBDQBS (JPW-6033)--optimized for blood-perfused tissue and intramural optical mapping. Voltage-dependent spectra were recorded in a model lipid bilayer. Optical mapping experiments were conducted in four species (mouse, rat, guinea pig, and pig). Hearts were Langendorff perfused using Tyrode's solution and blood (pig). Dyes were loaded via bolus injection into perfusate. Transillumination experiments were conducted in isolated coronary-perfused pig right ventricular wall preparations. The optimal excitation wavelength in cardiac tissues (650 nm) was >70 nm beyond the absorption maximum of hemoglobin. Voltage sensitivity of both dyes was approximately 10% to 20%. Signal decay half-life due to dye internalization was 80 to 210 minutes, which is 5 to 7 times slower than for di-4-ANEPPS. In transillumination mode, DeltaF/F was as high as 20%. In blood-perfused tissues, DeltaF/F reached 5.5% (1.8 times higher than for di-4-ANEPPS). We have synthesized and characterized two new near-infrared dyes with excitation/emission wavelengths shifted >100 nm to the red. They provide both high voltage sensitivity and 5 to 7 times slower internalization rate compared to conventional dyes. The dyes are optimized for deeper tissue probing and optical mapping of blood-perfused tissue, but they also can be used for conventional applications.

Fabrication of Natural Sensitizer Extracted from Mixture of Purple Cabbage, Roselle, Wormwood and Seaweed with High Conversion Efficiency for DSSC.

PubMed

Chang, Ho; Lai, Xuan-Rong

2016-02-01

This study aims to deal with the influence of different solvent in extraction of natural sensitizer and different thickness of photoelectrode thin film on the photoelectric conversion efficiency and the electron transport properties for the prepared dye-sensitized solar cells (DSSC). The natural dyes of anthocyanin and chlorophyll dyes are extracted from mixture of purple cabbage and roselle and mixture of wormwood and seaweed, respectively. The experimental results show the cocktail dye extracted with ethanol and rotating speed of spin coating at 1000 rpm can achieve the greatest photoelectric conversion efficiency up to 1.85%. Electrochemical impedance result shows that the effective diffusion coefficient for the prepared DSSC with the thickness of photoelectrode thin film at 21 microm are 5.23 x 10(-4) cm2/s.

Dye sensitized solar cell based on environmental friendly eosin Y dye and Al doped titanium dioxide nano particles

NASA Astrophysics Data System (ADS)

Kulkarni, Swati S.; Bodkhe, Gajanan A.; Shirsat, Sumedh M.; Hussaini, S. S.; Shejwal, N. N.; Shirsat, Mahendra D.

2018-03-01

Present communication deals with the development of cost effective dye sensitized solar cell (DSSC) with eco-friendly materials. Eco-friendly Eosin Y dye was used to sensitize photo anode which was fabricated using undoped and Aluminium doped titanium dioxide (TiO2) nanoparticles. Undoped and Aluminium doped TiO2 nanoparticles were synthesized by simple and cost effective sol-gel method. Aluminium doped and undoped TiO2 nanoparticles were characterized using UV-visible, FT-IR spectroscopy, x-ray Diffraction, and Scanning Electron Micrograph with EDX. The photo-voltaic activity of the cell was studied under light irradiation of 100 milliwatt cm-2. Aluminium doped TiO2 nanoparticle photo electrode exhibits more than 60% increase in cell efficiency as compared to the undoped TiO2 nanoparticle photo electrode.

Molecular engineering of fluorescein dyes as complementary absorbers in dye co-sensitized solar cells

DOE PAGES

Pepe, Giulio; Cole, Jacqueline M.; Waddell, Paul G.; ...

2016-09-22

Fluorescein dye derivatives exhibit extended optical absorption up to 500 nm, rendering these compounds suitable as co-absorbers in dye-sensitized solar cells (DSCs). A molecular engineering approach is presented, which embraces this intrinsic optical attribute of fluoresceins, while modifying the dye chemistry to enhance their light harvesting efficiency, in order to effectively tailor them for DSC applications. This approach first realizes relationships between the molecular structure and the optoelectronic properties for a series of five a priori known (parent) fluorescein dyes: 5-carboxyfluorescein (1), a mixture of m-carboxyfluorescein where m = 5 or 6 (2), 5-carboxyfluorescein diacetate (3), 6-carboxyfluorescein diacetate (4), amore » mixture of n-carboxy-2',7'-dichlorofluorescein diacetate where n = 5 or 6 (5). The first step in this approach combines, where available, experimental and computational methods so that electronic structure calculations can also be validated for representative fluorescein dyes. Such calculations can then be used reliably to predict the structure and properties of fluorescein dyes for cases where experimental data are lacking. Structure-function relationships established from this initial step inform the selection of parent dye 1 that is taken forward to the second step in molecular engineering: in silico chemical derivation to re-functionalize 1 for DSC applications. For this purpose, computational calculations are used to extend the charge conjugation in 1 between its donor and acceptor moieties. These structural modifications result in a bathochromic shift of the lowest excitation by ~1.3-1.9 eV (100-170 nm), making the dye optically absorb in the visible region. Further calculations on dye molecules adsorbed onto the surface of a TiO 2 cluster are used to investigate the dye sensitization behavior via dye adsorption energies and anchoring modes. The results of this theoretical investigation lead to two molecularly engineered fluoresceins being proposed to act as co-sensitizers together with a rhodamine dye. This combination of three dyes ensures chemical compatibility, panchromatic absorption, and restores optical absorption dipping otherwise observed in a DSC device at ~350-400 nm owing to the I-/I- 3 electrolyte. Altogether, the results of this study demonstrate that molecular engineering can be used to identify suitable chemical modifications for organic dyes with improved light harvesting properties for photovoltaic applications.« less

Molecular engineering of fluorescein dyes as complementary absorbers in dye co-sensitized solar cells

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

Pepe, Giulio; Cole, Jacqueline M.; Waddell, Paul G.

Fluorescein dye derivatives exhibit extended optical absorption up to 500 nm, rendering these compounds suitable as co-absorbers in dye-sensitized solar cells (DSCs). A molecular engineering approach is presented, which embraces this intrinsic optical attribute of fluoresceins, while modifying the dye chemistry to enhance their light harvesting efficiency, in order to effectively tailor them for DSC applications. This approach first realizes relationships between the molecular structure and the optoelectronic properties for a series of five a priori known (parent) fluorescein dyes: 5-carboxyfluorescein (1), a mixture of m-carboxyfluorescein where m = 5 or 6 (2), 5-carboxyfluorescein diacetate (3), 6-carboxyfluorescein diacetate (4), amore » mixture of n-carboxy-2',7'-dichlorofluorescein diacetate where n = 5 or 6 (5). The first step in this approach combines, where available, experimental and computational methods so that electronic structure calculations can also be validated for representative fluorescein dyes. Such calculations can then be used reliably to predict the structure and properties of fluorescein dyes for cases where experimental data are lacking. Structure-function relationships established from this initial step inform the selection of parent dye 1 that is taken forward to the second step in molecular engineering: in silico chemical derivation to re-functionalize 1 for DSC applications. For this purpose, computational calculations are used to extend the charge conjugation in 1 between its donor and acceptor moieties. These structural modifications result in a bathochromic shift of the lowest excitation by ~1.3-1.9 eV (100-170 nm), making the dye optically absorb in the visible region. Further calculations on dye molecules adsorbed onto the surface of a TiO 2 cluster are used to investigate the dye sensitization behavior via dye adsorption energies and anchoring modes. The results of this theoretical investigation lead to two molecularly engineered fluoresceins being proposed to act as co-sensitizers together with a rhodamine dye. This combination of three dyes ensures chemical compatibility, panchromatic absorption, and restores optical absorption dipping otherwise observed in a DSC device at ~350-400 nm owing to the I-/I- 3 electrolyte. Altogether, the results of this study demonstrate that molecular engineering can be used to identify suitable chemical modifications for organic dyes with improved light harvesting properties for photovoltaic applications.« less

Improvement of photovoltaic performance by substituent effect of donor and acceptor structure of TPA-based dye-sensitized solar cells.

PubMed

Inostroza, Natalia; Mendizabal, Fernando; Arratia-Pérez, Ramiro; Orellana, Carlos; Linares-Flores, Cristian

2016-01-01

We report a computational study of a series of organic dyes built with triphenylamine (TPA) as an electron donor group. We designed a set of six dyes called (TPA-n, where n = 0-5). In order to enhance the electron-injection process, the electron-donor effect of some specific substituent was studied. Thus, we gave insights into the rational design of organic TPA-based chromophores for use in dye-sensitized solar cells (DSSCs). In addition, we report the HOMO, LUMO, the calculated excited state oxidized potential E(dye*)(eV) and the free energy change for electron-injection ΔGinject(eV), and the UV-visible absorption bands for TPA-n dyes by a time-dependent density functional theory (TDDFT) procedure at the B3LYP and CAM-B3LYP levels with solvent effect. The results demonstrate that the introduction of the electron-acceptor groups produces an intramolecular charge transfer showing a shift of the absorption wavelengths of TPA-n under studies. Graphical Abstract Several organic dyes TPA-n with different donors and acceptors are modeled. A strong conjugation acrros the donor and anchoring groips (TPA-n) bas been studied. Candidate TPA-3 shows a promising results.

Voltage-sensitive dye recording from networks of cultured neurons

NASA Astrophysics Data System (ADS)

Chien, Chi-Bin

This thesis describes the development and testing of a sensitive apparatus for recording electrical activity from microcultures of rat superior cervical ganglion (SCG) neurons by using voltage-sensitive fluorescent dyes.The apparatus comprises a feedback-regulated mercury arc light source, an inverted epifluorescence microscope, a novel fiber-optic camera with discrete photodiode detectors, and low-noise preamplifiers. Using an NA 0.75 objective and illuminating at 10 W/cm2 with the 546 nm mercury line, a typical SCG neuron stained with the styryl dye RH423 gives a detected photocurrent of 1 nA; the light source and optical detectors are quiet enough that the shot noise in this photocurrent--about.03% rms--dominates. The design, theory, and performance of this dye-recording apparatus are discussed in detail.Styryl dyes such as RH423 typically give signals of 1%/100 mV on these cells; the signals are linear in membrane potential, but do not appear to arise from a purely electrochromic mechanism. Given this voltage sensitivity and the noise level of the apparatus, it should be possible to detect both action potentials and subthreshold synaptic potentials from SCG cell bodies. In practice, dye recording can easily detect action potentials from every neuron in an SCG microculture, but small synaptic potentials are obscured by dye signals from the dense network of axons.In another microculture system that does not have such long and complex axons, this dye-recording apparatus should be able to detect synaptic potentials, making it possible to noninvasively map the synaptic connections in a microculture, and thus to study long-term synaptic plasticity.

Altering the self-organization of dyes on titania with dyeing solvents to tune the charge-transfer dynamics of sensitized solar cells.

PubMed

Wang, Yinglin; Yang, Lin; Zhang, Jing; Li, Renzhi; Zhang, Min; Wang, Peng

2014-04-14

Herein we selected the model organic donor-acceptor dye C218 and modulated the self-organization of dye molecules on the surface of titania by changing the dyeing solvent from chlorobenzene to a mixture of acetonitrile and tert-butanol. We further unveiled the relationship between the microstructure of a dye layer and the multichannel charge-transfer dynamics that underlie the photovoltaic performance of dye-sensitized solar cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optical properties of natural dyes on the dye-sensitized solar cells (DSSC) performance

NASA Astrophysics Data System (ADS)

Pratiwi, D. D.; Nurosyid, F.; Supriyanto, A.; Suryana, R.

2016-11-01

This study reported several natural dyes for application in dye-sensitized solar cells (DSSC). This study aims was to determine the effect of optical absorption properties of natural dyes on efficiency of DSSC. The sandwich structure of DSSC consist of TiO2 as working electrode, carbon layer as counter electrode, natural dyes as photosensitizer, and electrolyte as electron transfer media. The natural dyes used in this experiment were extracted from dragon fruit anthocyanin, mangosteen peels anthocyanin, and red cabbage anthocyanin. The absorbance of dyes solutions and the adsorption of the dye on the surface of TiO2 were characterized using UV-Vis spectrophotometer, the quantum efficiency versus wavelength was characterized using incident photon-to-current efficiency (IPCE) measurement system, and the efficiency of DSSC was calculated using I-V meter. UV-Vis characteristic curves showed that wavelength absorption of anthocyanin dye of red cabbage was 450 - 580 nm, anthocyanin of mangosteen peels was 400 - 480 nm, and anthocyanin of dragon fruit was 400 - 650 nm. Absorption spectra of the dye adsorption on the surface of TiO2 which was resulted in the highest absorbance of red cabbage anthocyanin. IPCE characteristic curves with anthocyanin dye of red cabbage, mangosteen peels anthocyanin, and dragon fruit anthocyanin resulted quantum efficiency of 0.058%; 0.047%; and 0.043%, respectively at wavelength maximum about 430 nm. I-V characteristic curves with anthocyanin dye of red cabbage, mangosteen peels anthocyanin, and dragon fruit anthocyanin resulted efficiency of 0.054%; 0.042%; and 0.024%, respectively.

Skin sensitization quantitative risk assessment for occupational exposure of hairdressers to hair dye ingredients.

PubMed

Goebel, Carsten; Diepgen, Thomas L; Blömeke, Brunhilde; Gaspari, Anthony A; Schnuch, Axel; Fuchs, Anne; Schlotmann, Kordula; Krasteva, Maya; Kimber, Ian

2018-06-01

Occupational exposure of hairdressers to hair dyes has been associated with the development of allergic contact dermatitis (ACD) involving the hands. p-Phenylenediamine (PPD) and toluene-2,5-diamine (PTD) have been implicated as important occupational contact allergens. To conduct a quantitative risk assessment for the induction of contact sensitization to hair dyes in hairdressers, available data from hand rinsing studies following typical occupational exposure conditions to PPD, PTD and resorcinol were assessed. By accounting for wet work, uneven exposure and inter-individual variability for professionals, daily hand exposure concentrations were derived. Secondly, daily hand exposure was compared with the sensitization induction potency of the individual hair dye defined as the No Expected Sensitization Induction Levels (NESIL). For PPD and PTD hairdresser hand exposure levels were 2.7 and 5.9 fold below the individual NESIL. In contrast, hand exposure to resorcinol was 50 fold below the NESIL. Correspondingly, the risk assessment for PPD and PTD indicates that contact sensitization may occur, when skin protection and skin care are not rigorously applied. We conclude that awareness of health risks associated with occupational exposure to hair dyes, and of the importance of adequate protective measures, should be emphasized more fully during hairdresser education and training. Copyright © 2018 Elsevier Inc. All rights reserved.

Assessment of alginate hydrogel degradation in biological tissue using viscosity-sensitive fluorescent dyes

NASA Astrophysics Data System (ADS)

Shkand, Tatiana V.; Chizh, Mykola O.; Sleta, Iryna V.; Sandomirsky, Borys P.; Tatarets, Anatoliy L.; Patsenker, Leonid D.

2016-12-01

The main goal of this study is to investigate a combination of viscosity-sensitive and viscosity-insensitive fluorescent dyes to distinguish different rheological states of hydrogel based biostructural materials and carriers in biological tissues and to assess their corresponding location areas. The research is done in the example of alginate hydrogel stained with viscosity-sensitive dyes Seta-470 and Seta-560 as well as the viscosity-insensitive dye Seta-650. These dyes absorb/emit at 469/518, 565/591 and 651/670 nm, respectively. The rheological state of the alginate, the area of the fluorescence signal and the mass of the dense alginate versus the calcium gluconate concentration utilized for alginate gelation were studied in vitro. The most pronounced change in the fluorescence signal area was found at the same concentrations of calcium gluconate (below ~1%) as the change in the alginate plaque mass. The stained alginate was also implanted in situ in rat hip and myocardium and monitored using fluorescence imaging. In summary, our data indicate that the viscosity sensitive dye in combination with the viscosity-insensitive dye allow tracking the biodegradation of the alginate hydrogel and determining the rheological state of hydrogel in biological tissue, which both should have relevance for research and clinical applications. Using this method we estimated the half-life of the dense alginate hydrogel in a rat hip to be in the order of 4 d and about 6-8 d in rat myocardium. The half-life of the dense hydrogel in the myocardium was found to be long enough to prevent aneurysm rupture of the left ventricle wall, one of the more severe complications of the early post-infarction period.

Design of Far-Red Sensitizing Squaraine Dyes Aiming Towards the Fine Tuning of Dye Molecular Structure.

PubMed

Morimoto, Takuya; Fujikawa, Naotaka; Ogomi, Yuhei; Pandey, Shyam S; Ma, Tingli; Hayase, Shuzi

2016-04-01

Model squaraine dyes having sharp and narrow absorptions mainly in the far-red wavelength region has been logically designed, synthesized and used for their application as sensitizer in the dyesensitized solar cells (DSSC). In order to have fine control on energetics, dyes having same mother core and alkyl chain length varying only in molecular symmetry and position of substituent were designed. It has been found that even keeping all other structural factor constant, only positional variation of substituent leads to not only in the variation of energetics by 0.1 eV but affects the photovoltaic characteristics also. Optimum concentration of dye de-aggregating agent was found to be 100 times with respect to the sensitizing dye concentration. Amongst dyes utilized in this work best performance was obtained for unsymmetrical dye SQ-40 giving a photoconversion efficiency of 4.01% under simulated solar irradiation at global AM 1.5.

Dye ingredients and energy conversion efficiency at natural dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Özbay Karakuş, Mücella; Koca, İrfan; Er, Orhan; Çetin, Hidayet

2017-04-01

In this work, natural dyes extracted from the same genus but different species flowers were used as sensitizer in Dye Sensitized Solar Cell (DSSC). To clearly show dye ingredients effect on electrical characteristics, the same genus flowers were selected. The dye ingredients were analyzed by Gas Chromatography Mass Spectrometer (GC-MS). The dyes were modified by a procedure that includes refluxing in acetone. All results indicate a relationship between gallic acid quantity in dyes and solar cell efficiency. To gain further insight, the solar cell parameters were obtained by using the single-diode and double-diode models and they were compared to each other. It was observed that the applied process causes a decrease in series resistance. How the modification process and gallic acid affect energy conversion efficiency were argued in detail in the frame of results that were obtained from solar cell models.

Voltage-Sensitive Fluorescence of Indocyanine Green in the Heart

PubMed Central

Martišienė, Irma; Mačianskienė, Regina; Treinys, Rimantas; Navalinskas, Antanas; Almanaitytė, Mantė; Karčiauskas, Dainius; Kučinskas, Audrius; Grigalevičiūtė, Ramunė; Zigmantaitė, Vilma; Benetis, Rimantas; Jurevičius, Jonas

2016-01-01

So far, the optical mapping of cardiac electrical signals using voltage-sensitive fluorescent dyes has only been performed in experimental studies because these dyes are not yet approved for clinical use. It was recently reported that the well-known and widely used fluorescent dye indocyanine green (ICG), which has FDA approval, exhibits voltage sensitivity in various tissues, thus raising hopes that electrical activity could be optically mapped in the clinic. The aim of this study was to explore the possibility of using ICG to monitor cardiac electrical activity. Optical mapping experiments were performed on Langendorff rabbit hearts stained with ICG and perfused with electromechanical uncouplers. The residual contraction force and electrical action potentials were recorded simultaneously. Our research confirms that ICG is a voltage-sensitive dye with a dual-component (fast and slow) response to membrane potential changes. The fast component of the optical signal (OS) can have opposite polarities in different parts of the fluorescence spectrum. In contrast, the polarity of the slow component remains the same throughout the entire spectrum. Separating the OS into these components revealed two different voltage-sensitivity mechanisms for ICG. The fast component of the OS appears to be electrochromic in nature, whereas the slow component may arise from the redistribution of the dye molecules within or around the membrane. Both components quite accurately track the time of electrical signal propagation, but only the fast component is suitable for estimating the shape and duration of action potentials. Because ICG has voltage-sensitive properties in the entire heart, we suggest that it can be used to monitor cardiac electrical behavior in the clinic. PMID:26840736

Vibrational Spectroscopy on Photoexcited Dye-Sensitized Films via Pump-Degenerate Four-Wave Mixing.

PubMed

Abraham, Baxter; Fan, Hao; Galoppini, Elena; Gundlach, Lars

2018-03-01

Molecular sensitization of semiconductor films is an important technology for energy and environmental applications including solar energy conversion, photocatalytic hydrogen production, and water purification. Dye-sensitized films are also scientifically complex and interesting systems with a long history of research. In most applications, photoinduced heterogeneous electron transfer (HET) at the molecule/semiconductor interface is of critical importance, and while great progress has been made in understanding HET, many open questions remain. Of particular interest is the role of combined electronic and vibrational effects and coherence of the dye during HET. The ultrafast nature of the process, the rapid intramolecular vibrational energy redistribution, and vibrational cooling present complications in the study of vibronic coupling in HET. We present the application of a time domain vibrational spectroscopy-pump-degenerate four-wave mixing (pump-DFWM)-to dye-sensitized solid-state semiconductor films. Pump-DFWM can measure Raman-active vibrational modes that are triggered by excitation of the sample with an actinic pump pulse. Modifications to the instrument for solid-state samples and its application to an anatase TiO 2 film sensitized by a Zn-porphyrin dye are discussed. We show an effective combination of experimental techniques to overcome typical challenges in measuring solid-state samples with laser spectroscopy and observe molecular vibrations following HET in a picosecond time window. The cation spectrum of the dye shows modes that can be assigned to the linker group and a mode that is localized on the Zn-phorphyrin chromophore and that is connected to photoexcitation.

Dyes designed for high sensitivity detection of double-stranded DNA

DOEpatents

Glazer, Alexander N.; Benson, Scott C.

2000-01-01

Novel fluorescent dyes are provided, characterized by having a fluorophore joined to a cationic chain. The dyes are found to provide for high enhancement upon binding to nucleic acid and have strong binding affinities to the nucleic acid, as compared to the fluorophore without the polycationic chain. The dyes find use in detection of dsDNA in gel electrophoresis and solution at substantially higher sensitivities using substantially less dye.

Dyes designed for high sensitivity detection of double-stranded DNA

DOEpatents

Glazer, Alexander N.; Benson, Scott C.

1998-01-01

Novel fluorescent dyes are provided, characterized by having a fluorophore joined to a cationic chain. The dyes are found to provide for high enhancement upon binding to nucleic acid and have strong binding affinities to the nucleic acid, as compared to the fluorophore without the polycationic chain. The dyes find use in detection of dsDNA in gel electrophoresis and solution at substantially higher sensitivities using substantially less dye.

Cyanine dyes as optical contrast agents for ophthalmological surgery.

PubMed

Langhals, Heinz; Varja, Ana; Laubichler, Peter; Kernt, Marcus; Eibl, Kirsten; Haritoglou, Christos

2011-06-09

Cyanine dyes were prepared as optical contrast media for supporting the surgery of the lamina limitans interna (LLI) of the retina and other structures of the human eye. Their absorption spectra were adapted both to the spectral sensitivity of the human eye and to standard illumination. The contrast could be further amplified by the application of the strong fluorescence of the dyes used. The binding of the dyes to various surfaces was studied. No toxic effects could be detected for the applied dyes.

Efficient dye regeneration at low driving force achieved in triphenylamine dye LEG4 and TEMPO redox mediator based dye-sensitized solar cells.

PubMed

Yang, Wenxing; Vlachopoulos, Nick; Hao, Yan; Hagfeldt, Anders; Boschloo, Gerrit

2015-06-28

Minimizing the driving force required for the regeneration of oxidized dyes using redox mediators in an electrolyte is essential to further improve the open-circuit voltage and efficiency of dye-sensitized solar cells (DSSCs). Appropriate combinations of redox mediators and dye molecules should be explored to achieve this goal. Herein, we present a triphenylamine dye, LEG4, in combination with a TEMPO-based electrolyte in acetonitrile (E(0) = 0.89 V vs. NHE), reaching an efficiency of up to 5.4% under one sun illumination and 40% performance improvement compared to the previously and widely used indoline dye D149. The origin of this improvement was found to be the increased dye regeneration efficiency of LEG4 using the TEMPO redox mediator, which regenerated more than 80% of the oxidized dye with a driving force of only ∼0.2 eV. Detailed mechanistic studies further revealed that in addition to electron recombination to oxidized dyes, recombination of electrons from the conducting substrate and the mesoporous TiO2 film to the TEMPO(+) redox species in the electrolyte accounts for the reduced short circuit current, compared to the state-of-the-art cobalt tris(bipyridine) electrolyte system. The diffusion length of the TEMPO-electrolyte based DSSCs was determined to be ∼0.5 μm, which is smaller than the ∼2.8 μm found for cobalt-electrolyte based DSSCs. These results show the advantages of using LEG4 as a sensitizer, compared to previously record indoline dyes, in combination with a TEMPO-based electrolyte. The low driving force for efficient dye regeneration presented by these results shows the potential to further improve the power conversion efficiency (PCE) of DSSCs by utilizing redox couples and dyes with a minimal need of driving force for high regeneration yields.

Solvatochromic and Fluorogenic Dyes as Environment-Sensitive Probes: Design and Biological Applications.

PubMed

Klymchenko, Andrey S

2017-02-21

Fluorescent environment-sensitive probes are specially designed dyes that change their fluorescence intensity (fluorogenic dyes) or color (e.g., solvatochromic dyes) in response to change in their microenvironment polarity, viscosity, and molecular order. The studies of the past decade, including those of our group, have shown that these molecules become universal tools in fluorescence sensing and imaging. In fact, any biomolecular interaction or change in biomolecular organization results in modification of the local microenvironment, which can be directly monitored by these types of probes. In this Account, the main examples of environment-sensitive probes are summarized according to their design concepts. Solvatochromic dyes constitute a large class of environment-sensitive probes which change their color in response to polarity. Generally, they are push-pull dyes undergoing intramolecular charge transfer. Emission of their highly polarized excited state shifts to the red in more polar solvents. Excited-state intramolecular proton transfer is the second key concept to design efficient solvatochromic dyes, which respond to the microenvironment by changing relative intensity of the two emissive tautomeric forms. Due to their sensitivity to polarity and hydration, solvatochromic dyes have been successfully applied to biological membranes for studying lipid domains (rafts), apoptosis and endocytosis. As fluorescent labels, solvatochromic dyes can detect practically any type of biomolecular interactions, involving proteins, nucleic acids and biomembranes, because the binding event excludes local water molecules from the interaction site. On the other hand, fluorogenic probes usually exploit intramolecular rotation (conformation change) as a design concept, with molecular rotors being main representatives. These probes were particularly efficient for imaging viscosity and lipid order in biomembranes as well as to light up biomolecular targets, such as antibodies, aptamers and receptors. The emerging concepts to achieve fluorogenic response to the microenvironment include ground-state isomerization, aggregation-caused quenching, and aggregation-induced emission. The ground-state isomerization exploits, for instance, polarity-dependent spiro-lactone formation in silica-rhodamines. The aggregation-caused quenching uses disruption of the self-quenched dimers and nanoassemblies of dyes in less polar environments of lipid membranes and biomolecules. The aggregation-induced emission couples target recognition with formation of highly fluorescent dye aggregates. Overall, solvatochromic and fluorogenic probes enable background-free bioimaging in wash-free conditions as well as quantitative analysis when combined with advanced microscopy, such as fluorescence lifetime (FLIM) and ratiometric imaging. Further development of fluorescent environment-sensitive probes should address some remaining problems: (i) improving their optical properties, especially brightness, photostability, and far-red to near-infrared operating range; (ii) minimizing nonspecific interactions of the probes in biological systems; (iii) their adaptation for advanced microscopies, notably for superresolution and in vivo imaging.

Near-infrared sensitization in dye-sensitized solar cells.

PubMed

Park, Jinhyung; Viscardi, Guido; Barolo, Claudia; Barbero, Nadia

2013-01-01

Dye-sensitized solar cells (DSCs) are a low cost and colorful promising alternative to standard silicon photovoltaic cells. Though many of the highest efficiencies have been associated with sensitizers absorbing only in the visible portion of the solar radiation, there is a growing interest for NIR sensitization. This paper reviews the efforts made so far to find sensitizers able to absorb efficiently in the far-red NIR region of solar light. Panchromatic sensitizers as well as dyes absorbing mainly in the 650-920 nm region have been considered.

Fe-tannic acid complex dye as photo sensitizer for different morphological ZnO based DSSCs

NASA Astrophysics Data System (ADS)

Çakar, Soner; Özacar, Mahmut

2016-06-01

In this paper we have synthesized different morphological ZnO nanostructures via microwave hydrothermal methods at low temperature within a short time. We described different morphologies of ZnO at different Zn(NO3)2/KOH mole ratio. The ZnO nanostructures were characterized via X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV-vis spectrophotometry. All ZnO structures have hexagonal wurtzite type structures. The FESEM images showed various morphologies of ZnO such as plate, rod and nanoparticles. Dye sensitized solar cells have been assembled by these different morphological structures photo electrode and tannic acid or Fe-tannic acid complex dye as sensitizer. We have achieved at maximum efficiencies of photovoltaic cells prepared with ZnO plate in all dye systems. The conversion efficiencies of dye sensitized solar cells are 0.37% and 1.00% with tannic acid and Fe-tannic acid complex dye, respectively.

Photovoltaic studies of Dye Sensitized Solar cells Fabricated from Microwave Exposed Photo anodes

NASA Astrophysics Data System (ADS)

Ramachandran, Anju; Sreekala, C. O.; Sreelatha, K. S.; Jinchu, I.

2018-02-01

The configuration of Dye Sensitized solar cells (DSSC), consists of sintered nanoparticle titanium dioxide film, dyes, electrolyte and counter electrodes. Upon the absorption of photons by the dye molecules, excitons are generated, subsequently electrons are injected into the TiO2 photoanode. Afterward the electrons injected into the TiO2 photoanode, to produce photocurrent, scavenged by redox couple, and the hole transport to the photo cathode. The power conversion efficiency of the device depends on the amount of dye adsorbed by the photoanode. This paper explores in enhancing the efficiency of the device by controlled microwave exposure. With same exposure time, the photoanode is exposed at three different frequencies. SEM analysis is carried out to find the porosity of the photoanode on exposure. Current density is found to have an effect on microwave exposure.

Metal-free organic dyes for dye-sensitized solar cells: from structure: property relationships to design rules.

PubMed

Mishra, Amaresh; Fischer, Markus K R; Bäuerle, Peter

2009-01-01

Dye-sensitized solar cells (DSSC) have attracted considerable attention in recent years as they offer the possibility of low-cost conversion of photovoltaic energy. This Review focuses on recent advances in molecular design and technological aspects of metal-free organic dyes for applications in dye-sensitized solar cells. Special attention has been paid to the design principles of these dyes and on the effect of various electrolyte systems. Cosensitization, an emerging technique to extend the absorption range, is also discussed as a way to improve the performance of the device. In addition, we report on inverted dyes for photocathodes, which constitutes a relatively new approach for the production of tandem cells. Special consideration has been paid to the correlation between the molecular structure and physical properties to their performance in DSSCs.

Effect of polymer electrolyte on the performance of natural dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Adel, R.; Abdallah, T.; Moustafa, Y. M.; Al-sabagh, A. M.; Talaat, H.

2015-10-01

Polymer electrolyte based on polyacrylonitrile (PAN), Ethylene Carbonate (EC) and Acetonitrile (ACN) mixed with Potassium Iodide and Iodine in liquid and thin film forms were employed in natural dye sensitized solar cells (NDSSCs). Three natural dyes; black berry, hibiscus and rose are used as the sensitizing dye. The NDSSCs used, follow the configuration: FTO/TiO2/Natural Dye/Electrolyte/ Carbon/FTO. The liquid form polymer electrolyte with black berry natural dye gives an increase of 111% in short circuit photocurrent density (Jsc), 17.5% to open circuit voltage (Voc), fill factor of 0.57 ± 0.05 and three times increase in the conversion efficiency of 0.242 ± 0.012% compared to the iodine electrolyte.

Dyes designed for high sensitivity detection of double-stranded DNA

DOEpatents

Glazer, A.N.; Benson, S.C.

1998-07-21

Novel fluorescent dyes are provided, characterized by having a fluorophore joined to a cationic chain. The dyes are found to provide for high enhancement upon binding to nucleic acid and have strong binding affinities to the nucleic acid, as compared to the fluorophore without the polycationic chain. The dyes find use in detection of dsDNA in gel electrophoresis and solution at substantially higher sensitivities using substantially less dye. 10 figs.

Effect of microwave exposure on the photo anode of DSSC sensitized with natural dye

NASA Astrophysics Data System (ADS)

Swathi, K. E.; Jinchu, I.; Sreelatha, K. S.; Sreekala, C. O.; Menon, Sreedevi K.

2018-02-01

Dye Sensitized solar cells (DSSC) are also referred to as dye sensitised cells (DSC) or Graetzel cell are the device that converts solar energy in to electricity by the photovoltaic effect. This is the class of advanced cell that mimics the artificial photosynthesis. DSSC fabrication is simple and can be done using readily available low cost materials that are nontoxic, environment friendly and works even under low flux of sunlight. DSSC exhibits good efficiency of ~ 10-14 %. This paper emphasis on the study of enhancing the efficiency of DSSC by exposing the photo anode to microwave frequency. Effect of duration of microwave exposure at 2.6 GHz on energy efficiency of solar cell is studied in detail. The SEM analysis and dye desorption studies of the photo anode confirms an increased solar energy conversion efficiency of the DSSC.

Norcyanine dyes with benzo[c,d]indolium moiety: Spectral sensitivity with pH change for fluorescence pH imaging in living cells.

PubMed

Guan, Li; Liu, Qi; Zhang, Borui; Wang, Lanying

2017-01-01

Fluorescence pH imaging in living cells is a rapidly expanding research direction, however, it relies on the development of pH-sensitive fluorescent imaging agents. Here four norcyanine dyes with benzo[c,d]indolium moiety, exhibiting high spectral sensitivity with pH changes, were synthesized for fluorescence pH imaging in living cells, and characterized by 1 H NMR, 13 C NMR, IR, UV-Vis and HRMS. The investigation of their spectral properties in methanol and water showed that the absorption and emission maxima were in the region 488-618nm and 583-651nm, respectively, and four dyes exhibited high photostability. The pH spectral titrations showed that selective dye D1 had pH-dependent absorption spectral changes within the pH range of 2.4 to 9.4, and high fluorescent spectral sensitivity at pH5.0-8.0, with a pK a of 5.0. A cell association study indicated that dye D1 exhibited no or mild cytotoxicity at the application dose and duration, and could be accumulated in cells and mainly distributed in the cytoplasm, giving red fluorescence imaging. In particular, dye D1 could achieve pH-dependent fluorescence imaging in living cells with the increase of pH from 3.0 to 8.0, at excitation wavelength of 543nm and receiving wavelength of 655-755nm, which was valuable for studying the weak acidic, neutral and weak alkaline biological tissue compartments. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular design of donor-acceptor dyes for efficient dye-sensitized solar cells I: a DFT study.

PubMed

El-Shishtawy, Reda M; Asiri, Abdullah M; Aziz, Saadullah G; Elroby, Shaaban A K

2014-06-01

Dye-sensitized solar cells (DSSCs) have drawn great attention as low cost and high performance alternatives to conventional photovoltaic devices. The molecular design presented in this work is based on the use of pyran type dyes as donor based on frontier molecular orbitals (FMO) and theoretical UV-visible spectra in combination with squaraine type dyes as an acceptor. Density functional theory has been used to investigate several derivatives of pyran type dyes for a better dye design based on optimization of absorption, regeneration, and recombination processes in gas phase. The frontier molecular orbital (FMO) of the HOMO and LUMO energy levels plays an important role in the efficiency of DSSCs. These energies contribute to the generation of exciton, charge transfer, dissociation and exciton recombination. The computations of the geometries and electronic structures for the predicted dyes were performed using the B3LYP/6-31+G** level of theory. The FMO energies (EHOMO, ELUMO) of the studied dyes are calculated and analyzed in the terms of the UV-visible absorption spectra, which have been examined using time-dependent density functional theory (TD-DFT) techniques. This study examined absorption properties of pyran based on theoretical UV-visible absorption spectra, with comparisons between TD-DFT using B3LYP, PBE, and TPSSH functionals with 6-31+G (d) and 6-311++G** basis sets. The results provide a valuable guide for the design of donor-acceptor (D-A) dyes with high molar absorptivity and current conversion in DSSCs. The theoretical results indicated 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran dye (D2-Me) can be effectively used as a donor dye for DSSCs. This dye has a low energy gap by itself and a high energy gap with squaraine acceptor type dye, the design that reduces the recombination and improves the photocurrent generation in solar cell.

Voltage-sensitive styryl dyes as singlet oxygen targets on the surface of bilayer lipid membrane.

PubMed

Sokolov, V S; Gavrilchik, A N; Kulagina, A O; Meshkov, I N; Pohl, P; Gorbunova, Yu G

2016-08-01

Photosensitizers are widely used as photodynamic therapeutic agents killing cancer cells by photooxidation of their components. Development of new effective photosensitive molecules requires profound knowledge of possible targets for reactive oxygen species, especially for its singlet form. Here we studied photooxidation of voltage-sensitive styryl dyes (di-4-ANEPPS, di-8-ANEPPS, RH-421 and RH-237) by singlet oxygen on the surface of bilayer lipid membranes commonly used as cell membrane models. Oxidation was induced by irradiation of a photosensitizer (aluminum phthalocyanine tetrasulfonate) and monitored by the change of dipole potential on the surface of the membrane. We studied the drop of the dipole potential both in the case when the dye molecules were adsorbed on the same side of the lipid bilayer as the photosensitizer (cis-configuration) and in the case when they were adsorbed on the opposite side (trans-configuration). Based on a simple model, we determined the rate of oxidation of the dyes from the kinetics of change of the potential during and after irradiation. This rate is proportional to steady-state concentration of singlet oxygen in the membrane under irradiation. Comparison of the oxidation rates of various dyes reveals that compounds of ANEPPS series are more sensitive to singlet oxygen than RH type dyes, indicating that naphthalene group is primarily responsible for their oxidation. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of type-I/type-II hybrid dye sensitizer with both pyridyl group and catechol unit as anchoring group for type-I/type-II dye-sensitized solar cell.

PubMed

Ooyama, Yousuke; Furue, Kensuke; Enoki, Toshiaki; Kanda, Masahiro; Adachi, Yohei; Ohshita, Joji

2016-11-09

A type-I/type-II hybrid dye sensitizer with a pyridyl group and a catechol unit as the anchoring group has been developed and its photovoltaic performance in dye-sensitized solar cells (DSSCs) is investigated. The sensitizer has the ability to adsorb on a TiO 2 electrode through both the coordination bond at Lewis acid sites and the bidentate binuclear bridging linkage at Brønsted acid sites on the TiO 2 surface, which makes it possible to inject an electron into the conduction band of the TiO 2 electrode by the intramolecular charge-transfer (ICT) excitation (type-I pathway) and by the photoexcitation of the dye-to-TiO 2 charge transfer (DTCT) band (type-II pathway). It was found that the type-I/type-II hybrid dye sensitizer adsorbed on TiO 2 film exhibits a broad photoabsorption band originating from ICT and DTCT characteristics. Here we reveal the photophysical and electrochemical properties of the type-I/type-II hybrid dye sensitizer bearing a pyridyl group and a catechol unit, along with its adsorption modes onto TiO 2 film, and its photovoltaic performance in type-I/type-II DSSC, based on optical (photoabsorption and fluorescence spectroscopy) and electrochemical measurements (cyclic voltammetry), density functional theory (DFT) calculation, FT-IR spectroscopy of the dyes adsorbed on TiO 2 film, photocurrent-voltage (I-V) curves, incident photon-to-current conversion efficiency (IPCE) spectra, and electrochemical impedance spectroscopy (EIS) for DSSC.

Visible Light-Induced Carbonylation Reactions with Organic Dyes as the Photosensitizers.

PubMed

Peng, Jin-Bao; Qi, Xinxin; Wu, Xiao-Feng

2016-09-08

Dyes can CO do it: Organic dyes and pigments are usually applied in textile dyeing, which can be dated back to the Neolithic period. Interestingly, the possibility to use organic dyes as photoredox catalysts has also been noticed by organic chemists and applied in organic synthesis. Carbonylation reactions as a powerful procedure in carbonyl-containing compound preparation have also been studied. In this manuscript, the recent achievements in using organic dyes as visible-light sensitizers in carbonylation chemistry are summarized and discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pigments for natural dye-sensitized solar cells from in vitro grown shoot cultures

NASA Astrophysics Data System (ADS)

Di Bari, Chiara; Forni, Cinzia; Di Carlo, Aldo; Barrajón-Catalán, Enrique; Micol, Vicente; Teoli, Federico; Nota, Paolo; Matteocci, Fabio; Frattarelli, Andrea; Caboni, Emilia; Lucioli, Simona

2017-04-01

In vitro grown shoots cultures (Prunus salicina × Prunus persica), elicited by methyl jasmonate (MJ), are reported here for the first time to prepare a natural dye for dye-sensitized solar cells (DSSC). Redox properties of the dye, its photostability, and light absorption properties suggested it as a candidate as natural photosensitizers for TiO2 photoelectrodes. Redox properties of the dye influence the DSSC production of photocurrent, thus three antioxidant assays were performed in order to characterize the antioxidant potential of this dye. The dye exhibited a high antioxidant activity in all the assays performed. Photostability assay revealed that the dye was quite stable to light. The power conversion efficiency that we obtained (0.53%) was comparable to the data by other authors with anthocyanins-based dyes from in vivo grown plants. Finally, we compared the dye with the partially purified one as photosensitizer in DSSC. The results indicated that the raw pigment from in vitro shoot cultures of P. salicina × P. persica elicited with MJ can be proposed without the needing of any other chemicals, thermal or purification process, or pH adjustments, as a dye for natural sensitized solar cells.

Carbachol-induced fluid movement through methazolamide-sensitive bicarbonate production in rat parotid intralobular ducts: quantitative analysis of fluorescence images using fluorescent dye sulforhodamine under a confocal laser scanning microscope.

PubMed

Nakamoto, Tetsuji; Shiba, Yoshiki; Hirono, Chikara; Sugita, Makoto; Takemoto, Kazuhisa; Iwasa, Yoshiko; Akagawa, Yasumasa

2002-09-01

Fluid secretion is observed at the openings of ducts in the exocrine gland. It remains unclear whether the ducts are involved in fluid secretion in the salivary glands. In the present study, we investigated the exclusion of fluorescent dye from the duct lumen by carbachol (CCh) in isolated parotid intralobular duct segments to clarify the ability of the ducts for the fluid secretion. When the membrane-impermeable fluorescent dye, sulforhodamine, was added to the superfused extracellular solution, quantitative fluorescence images of the duct lumen were obtained under the optical sectioning at the level of the duct lumen using a confocal laser scanning microscope. CCh decreased the fluorescent intensity in the duct lumen during the superfusion of the fluorescent dye, and CCh flushed out small viscous substances stained with the fluorescent dye from isolated duct lumen, suggesting that CCh might induce fluid secretion in the duct, leading to the clearance of the dye and small stained clumps from the duct lumen. CCh-induced clearance of the fluorescent dye was divided into two phases by the sensitivity to external Ca2+ and methazolamide, an inhibitor for carbonic anhydrase. The initial phase was insensitive to these, and the subsequent late phase was sensitive to these. A major portion in the late phase was inhibited by removal of bicarbonate in the superfusion solution and DPC, but not low concentration of external Cl-, bumetanide or DIDS, suggesting that methazolamide-sensitive production of HCO3-, but not the Cl- uptake mechanism, might contribute to the CCh-induced clearance of the dye from the duct lumen. These results represent the first measurements of fluid movement in isolated duct segments, and suggest that carbachol might evoke fluid secretion possibly through Ca2+-activated, DPC-sensitive anion channels with HCO3- secretion in the rat parotid intralobular ducts.

Dyes designed for high sensitivity detection of double-stranded DNA

DOEpatents

Glazer, Alexander N.; Benson, Scott C.

1994-01-01

Novel fluorescent dyes are provided, characterized by having a fluorophore joined to a polycationic chain of at least two positive charges. The dyes are found to provide for high enhancement upon binding to nucleic acid and have strong binding affinities to the nucleic acid, as compared to the fluorophore without the polycationic chain. The dyes find use in detection of dsDNA in gel electrophoresis and solution at substantially higher sensitivities using substantially less dye.

Monolithic-Structured Single-Layered Textile-Based Dye-Sensitized Solar Cells.

PubMed

Yun, Min Ju; Cha, Seung I; Kim, Han Seong; Seo, Seon Hee; Lee, Dong Y

2016-10-06

Textile-structured solar cells are frequently discussed in the literature due to their prospective applications in wearable devices and in building integrated solar cells that utilize their flexibility, mechanical robustness, and aesthetic appearance, but the current approaches for textile-based solar cells-including the preparation of fibre-type solar cells woven into textiles-face several difficulties from high friction and tension during the weaving process. This study proposes a new structural concept and fabrication process for monolithic-structured textile-based dye-sensitized solar cells that are fabricated by a process similar to the cloth-making process, including the preparation of wires and yarns that are woven for use in textiles, printed, dyed, and packaged. The fabricated single-layered textile-based dye-sensitized solar cells successfully act as solar cells in our study, even under bending conditions. By controlling the inter-weft spacing and the number of Ti wires for the photoelectrode conductor, we have found that the performance of this type of dye-sensitized solar cell was notably affected by the spacing between photoelectrodes and counter-electrodes, the exposed areas of Ti wires to photoelectrodes, and photoelectrodes' surface morphology. We believe that this study provides a process and concept for improved textile-based solar cells that can form the basis for further research.

Dyes and Redox Couples with Matched Energy Levels: Elimination of the Dye-Regeneration Energy Loss in Dye-Sensitized Solar Cells.

PubMed

Jiang, Dianlu; Darabedian, Narek; Ghazarian, Sevak; Hao, Yuanqiang; Zhgamadze, Maxim; Majaryan, Natalie; Shen, Rujuan; Zhou, Feimeng

2015-11-16

In dye-sensitized solar cells (DSSCs), a significant dye-regeneration force (ΔG(reg)(0)≥0.5 eV) is usually required for effective dye regeneration, which results in a major energy loss and limits the energy-conversion efficiency of state-of-art DSSCs. We demonstrate that when dye molecules and redox couples that possess similar conjugated ligands are used, efficient dye regeneration occurs with zero or close-to-zero driving force. By using Ru(dcbpy)(bpy)2(2+) as the dye and Ru(bpy)2(MeIm)2(3+//2+) as the redox couple, a short-circuit current (J(sc)) of 4 mA cm(-2) and an open-circuit voltage (V(oc)) of 0.9 V were obtained with a ΔG(reg)(0) of 0.07 eV. The same was observed for the N3 dye and Ru(bpy)2(SCN)2(1+/0) (ΔG(reg)(0)=0.0 eV), which produced an J(sc) of 2.5 mA cm(-2) and V(oc) of 0.6 V. Charge recombination occurs at pinholes, limiting the performance of the cells. This proof-of-concept study demonstrates that high V(oc) values can be attained by significantly curtailing the dye-regeneration force. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Significance of hair-dye base-induced sensory irritation.

PubMed

Fujita, F; Azuma, T; Tajiri, M; Okamoto, H; Sano, M; Tominaga, M

2010-06-01

Oxidation hair-dyes, which are the principal hair-dyes, sometimes induce painful sensory irritation of the scalp caused by the combination of highly reactive substances, such as hydrogen peroxide and alkali agents. Although many cases of severe facial and scalp dermatitis have been reported following the use of hair-dyes, sensory irritation caused by contact of the hair-dye with the skin has not been reported clearly. In this study, we used a self-assessment questionnaire to measure the sensory irritation in various regions of the body caused by two model hair-dye bases that contained different amounts of alkali agents without dyes. Moreover, the occipital region was found as an alternative region of the scalp to test for sensory irritation of the hair-dye bases. We used this region to evaluate the relationship of sensitivity with skin properties, such as trans-epidermal water loss (TEWL), stratum corneum water content, sebum amount, surface temperature, current perception threshold (CPT), catalase activities in tape-stripped skin and sensory irritation score with the model hair-dye bases. The hair-dye sensitive group showed higher TEWL, a lower sebum amount, a lower surface temperature and higher catalase activity than the insensitive group, and was similar to that of damaged skin. These results suggest that sensory irritation caused by hair-dye could occur easily on the damaged dry scalp, as that caused by skin cosmetics reported previously.

Fabrication and Characterization of Sansevieria trifasciata, Pandanus amaryllifolius and Cassia angustifolia as Photosensitizer for Dye Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Cari; Supriyanto, Agus; Mahfudli Fadli, Ulfa; Bayu Prasada, Ashari

2016-04-01

Dye sensitized Solar Cells (DSSC) is one of the electric cells photochemical consisting of photoelectrode, dye, counter electrode, and electrolyte. The aims of the research to determine of the optical and electrical characteristic of the extract Sansevieria trifasciata, Pandanus amaryllifolius, and Cassia angustifolia. The study is also aimed to determine the effect of natural dyes extract to increase the efficiency of solar cells based DSSC. Sandwich structures formed in the sample consisted of working electrode pair Titanium dioxide (TiO2) and the counter electrode platinum (Pt). Dye extraction process is performed by stirring for 1 hour and then allowed to stand for 24 hours. Absorbance test is measure by using UV-Vis spectrophotometer Lambda 25, conductivity test by using a two-point probes Elkahfi 100, and characterization of current and voltage (I-V) by using a Keithley 2602A. The results showed that the greatest efficiency of 0.160% at Dye Pandanus amaryllifolius.

Towards Sustainable H2 Production: Rational Design of Hydrophobic Triphenylamine-based Dyes for Sensitized Ethanol Photoreforming.

PubMed

Dessì, Alessio; Monai, Matteo; Bessi, Matteo; Montini, Tiziano; Calamante, Massimo; Mordini, Alessandro; Reginato, Gianna; Trono, Cosimo; Fornasiero, Paolo; Zani, Lorenzo

2018-02-22

Donor-acceptor dyes are a well-established class of photosensitizers, used to enhance visible-light harvesting in solar cells and in direct photocatalytic reactions, such as H 2 production by photoreforming of sacrificial electron donors (SEDs). Amines-typically triethanolamine (TEOA)-are commonly employed as SEDs in such reactions. Dye-sensitized photoreforming of more sustainable, biomass-derived alcohols, on the other hand, was only recently reported by using methanol as the electron donor. In this work, several rationally designed donor-acceptor dyes were used as sensitizers in H 2 photocatalytic production, comparing the efficiency of TEOA and EtOH as SEDs. In particular, the effect of hydrophobic chains in the spacer and/or the donor unit of the dyes was systematically studied. The H 2 production rates were higher when TEOA was used as SED, whereas the activity trends depended on the SED used. The best performance was obtained with TEOA by using a sensitizer with just one bulky hydrophobic moiety, propylenedioxythiophene, placed on the spacer unit. In the case of EtOH, the best-performing sensitizers were the ones featuring a thiazolo[5,4-d]thiazole internal unit, needed for enhancing light harvesting, and carrying alkyl chains on both the donor part and the spacer unit. The results are discussed in terms of reaction mechanism, interaction with the SED, and structural/electrochemical properties of the sensitizers. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

To probe the equivalence and opulence of nanocrystal and nanotube based dye-sensitized solar cells

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

Jyoti, Divya, E-mail: divyabathla17@gmail.com; Mohan, Devendra

2016-05-06

Dye-Sensitized solar cells based on TiO{sub 2} nanocrystal and TiO{sub 2} nanotubes have been fabricated by a simple sol-gel hydrothermal process and their performances have been compared. Current density and voltage (JV) characteristics and incident photon to current conversion efficiency (IPCE) plots have been set as criterion to check which one is better as a photoanode candidate in dye-sensitized solar cell. It has been observed that although open circuit voltage values for both type of cells do not differ much still, nanotube based dye-sensitized solar cells are more successful having an efficiency value of 7.28%.

Analysis of Chameleonic Change of Red Cabbage Depending on Broad pH Range for Dye-Sensitized Solar Cells.

PubMed

Park, Kyung Hee; Kim, Tae Young; Ko, Hyun Seok; Han, Eun Mi; Lee, Suk-Ho; Kim, Jung-Hun; Lee, Jae Wook

2015-08-01

Dye-sensitized solar cells (DSSCs) were assembled using natural dyes extracted from red cabbage as a sensitizer. In this work, we investigated the adsorption characteristics and the electrochemical behavior for harvesting sunlight and electron transfer in red cabbage DSSCs under different solvents and pH. For the red cabbage dye-sensitized electrode adsorbed at pH 3.5, the solar cell yields a short-circuit current density (Jsc) of 1.60 mA/cm2, a photovoltage (Vcc) of 0.46 V, and a fill factor of 0.55, corresponding to an energy conversion efficiency (η) of 0.41%.

Green grasses as light harvesters in dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Shanmugam, Vinoth; Manoharan, Subbaiah; Sharafali, A.; Anandan, Sambandam; Murugan, Ramaswamy

2015-01-01

Chlorophylls, the major pigments presented in plants are responsible for the process of photosynthesis. The working principle of dye sensitized solar cell (DSSC) is analogous to natural photosynthesis in light-harvesting and charge separation. In a similar way, natural dyes extracted from three types of grasses viz. Hierochloe Odorata (HO), Torulinium Odoratum (TO) and Dactyloctenium Aegyptium (DA) were used as light harvesters in dye sensitized solar cells (DSSCs). The UV-Vis absorption spectroscopy, Fourier transform infrared (FT-IR), and liquid chromatography-mass spectrometry (LC-MS) were used to characterize the dyes. The electron transport mechanism and internal resistance of the DSSCs were investigated by the electrochemical impedance spectroscopy (EIS). The performance of the cells fabricated with the grass extract shows comparable efficiencies with the reported natural dyes. Among the three types of grasses, the DSSC fabricated with the dye extracted from Hierochloe Odorata (HO) exhibited the maximum efficiency. LC-MS investigations indicated that the dominant pigment present in HO dye was pheophytin a (Pheo a).

Potential of roselle and blue pea in the dye-sensitized solar cell

NASA Astrophysics Data System (ADS)

Dayang, S.; Irwanto, M.; Gomesh, N.; Ismail, B.

2017-09-01

This paper discovers the use of natural dyes from Roselle flower and Blue Pea flower which act as a sensitizer in DSSC and in addition has a potential in absorbing visible light spectrum. The dyes were extracted using distilled water (DI) and ethanol (E) extract solvent in an ultrasonic cleaner for 30 minutes with a frequency of 37 Hz by using `degas' mode at the temperature of 30°C. Absorption spectra of roselle dye and blue pea dye with different extract solvent were tested using Evolution 201 UV-Vis Spectrophotometer. It was found that Roselle dye absorbs at a range of 400 nm - 620 nm and Blue Pea absorbs at the range of wavelength 500 nm - 680 nm. Fourier-Transform Infrared (FTIR) was used to identify the functional active group in extract dye. The concept of Dye-Sensitized Solar Cell (DSSC) similar to photosynthesis process has attracted much attention since it demonstrates a great potential due to the use of low-cost materials and environmentally friendly sources of technology.

Influence of structural variations in push-pull zinc porphyrins on photovoltaic performance of dye-sensitized solar cells.

PubMed

Yi, Chenyi; Giordano, Fabrizio; Cevey-Ha, Ngoc-Le; Tsao, Hoi Nok; Zakeeruddin, Shaik M; Grätzel, Michael

2014-04-01

We designed and synthesized two new zinc porphyrin dyes for dye-sensitized solar cells (DSCs). Subtle molecular structural variation in the dyes significantly influenced the performance of the DSC devices. By utilizing these dyes in combination with a cobalt-based redox electrolyte using a photoanode made of mesoporous TiO2 , we achieved a power conversion efficiency (PCE) of up to 12.0 % under AM 1.5 G (100 mW cm(-2)) simulated solar light. Moreover, we obtained a high PCE of 6.4 % for solid-state dye-sensitized solar cells by using 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene as a hole-transporting material. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensitization of photoconductivity in ferrocene-containing oligomer by squarylium and merocyanine dyes

NASA Astrophysics Data System (ADS)

Davidenko, N. A.; Ishchenko, A. A.; Kozinets, A. V.; Kostenko, L. I.; Kurdyukova, I. V.; Mokrinskaya, E. V.; Studzinskii, S. L.; Chuprina, N. G.

2011-03-01

We have studied the photoconducting properties of films of ferrocene-containing oligomer with additives of squarylium and merocyanine dyes based on ferrocene and tetranitrofluorene in the dye absorption region. We have studied the characteristic features of the effect of an external magnetic field on the photocurrents. After the magnetic field is turned on, the photocurrent increases in the samples with squarylium dye and decreases in the samples with merocyanine dye. We discuss the hypothesis that in the first case, as a result of an internal photoelectric effect, predominantly triplet charge pairs are formed, while in the second case predominantly singlet charge pairs are formed. The latter may be one of the reasons for the higher photoconductivity of films with squarylium dye compared with merocyanine dye.

A Rationally Designed, General Strategy for Membrane Orientation of Photoinduced Electron Transfer-Based Voltage-Sensitive Dyes.

PubMed

Kulkarni, Rishikesh U; Yin, Hang; Pourmandi, Narges; James, Feroz; Adil, Maroof M; Schaffer, David V; Wang, Yi; Miller, Evan W

2017-02-17

Voltage imaging with fluorescent dyes offers promise for interrogating the complex roles of membrane potential in coordinating the activity of neurons in the brain. Yet, low sensitivity often limits the broad applicability of optical voltage indicators. In this paper, we use molecular dynamics (MD) simulations to guide the design of new, ultrasensitive fluorescent voltage indicators that use photoinduced electron transfer (PeT) as a voltage-sensing switch. MD simulations predict an approximately 16% increase in voltage sensitivity resulting purely from improved alignment of dye with the membrane. We confirm this theoretical finding by synthesizing 9 new voltage-sensitive (VoltageFluor, or VF) dyes and establishing that all of them display the expected improvement of approximately 19%. This synergistic outworking of theory and experiment enabled computational and theoretical estimation of VF dye orientation in lipid bilayers and has yielded the most sensitive PeT-based VF dye to date. We use this new voltage indicator to monitor voltage spikes in neurons from rat hippocampus and human pluripotent-stem-cell-derived dopaminergic neurons.

Dye-sensitized solar cells using Aloe Vera and Cladode of Cactus extracts as natural sensitizers

NASA Astrophysics Data System (ADS)

Ganta, D.; Jara, J.; Villanueva, R.

2017-07-01

The purpose of this study is to develop dye-sensitized solar cells (DSSCs) from natural plant-based dyes, extracted from the Cladode (nopal) of the Thornless Prickly Pear Cactus (Opuntia ficus-indica), the gel of Aloe Vera (Aloe barbadensis miller), and the combination of Cladode and Aloe Vera extracts on side-by-side configuration. Optical properties were analyzed using UV-Vis Absorption and Fourier Transform Infrared Spectroscopy. Open circuit voltages (Voc) varied from 0.440 to 0.676 V, fill factors (FF) were greater than 40%, short-circuit photocurrent densities (Jsc) ranged from 0.112 to 0.290 mA/cm2 and highest conversion efficiency of 0.740% was reported for the Cladode DSSC.

Molecularly Engineered Ru(II) Sensitizers Compatible with Cobalt(II/III) Redox Mediators for Dye-Sensitized Solar Cells.

PubMed

Wu, Kuan-Lin; Huckaba, Aron J; Clifford, John N; Yang, Ya-Wen; Yella, Aswani; Palomares, Emilio; Grätzel, Michael; Chi, Yun; Nazeeruddin, Mohammad Khaja

2016-08-01

Thiocyanate-free isoquinazolylpyrazolate Ru(II) complexes were synthesized and applied as sensitizers in dye-sensitized solar cells (DSCs). Unlike most other successful Ru sensitizers, Co-based electrolytes were used, and resulting record efficiency of 9.53% was obtained under simulated sunlight with an intensity of 100 mW cm(-2). Specifically, dye 51-57dht.1 and an electrolyte based on Co(phen)3 led to measurement of a JSC of 13.89 mA cm(-2), VOC of 900 mV, and FF of 0.762 to yield 9.53% efficiency. The improved device performances were achieved by the inclusion of 2-hexylthiophene units onto the isoquinoline subunits, in addition to lengthening the perfluoroalkyl chain on the pyrazolate chelating group, which worked to increase light absorption and decrease recombination effects when using the Co-based electrolyte. As this study shows, Ru(II) sensitizers bearing sterically demanding ligands can allow successful utilization of important Co electrolytes and high performance.

A Hybrid Tandem Solar Cell Combining a Dye-Sensitized and a Polymer Solar Cell.

PubMed

Shao, Zhipeng; Chen, Shuanghong; Zhang, Xuhui; Zhu, Liangzheng; Ye, Jiajiu; Dai, Songyuan

2016-06-01

A hybrid tandem solar cell was assambled by connecting a dye sensitized solar cell and a polymer solar cell in series. A N719 sensitized TiO2 was used as photocathode in dye-sensitized subcell, and a MEH-PPV/PCBM composite was used as active layer in the polymer subcell. The polymer subcell fabricated on the counter electrode of the dye sensitized solar cell. A solution processed TiO(x) layer was used as electron collection layer of the polymer sub cell and the charge recombination layer. The effects of the TiO(x) interlayer and the spectral overlap between the two sub cells have been studied and optimized. The results shows that a proper thickness of the TiO(x) layer is needed for tandem solar cells. Thick TiO(x) will enhance the series resistance, but too thin TiO(x), layer will damage the hole blocking effect and its hydrophilic. The resulting optimized tandem solar cells exhibited a power conversion efficiency of 1.28% with a V(oc) of 0.95 V under simulated 100 mW cm(-2) AM 1.5 illumination.

Fabrication, characterization of two nano-composite CuO-ZnO working electrodes for dye-sensitized solar cell.

PubMed

Habibi, Mohammad Hossein; Karimi, Bahareh; Zendehdel, Mahmoud; Habibi, Mehdi

2013-12-01

Two kind of CuO-ZnO nanocomposite working electrodes were synthesized by sol-gel technology and applied in dye-sensitized solar cells (DSSCs). Their characteristics were studied by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). CuO-ZnO nanocomposite thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)3](PF6)2, [Co(pby)3](PF6)3, LiClO4, and 4-tert-butylpyridine (TBP). The ranges of short-circuit current (JSC) from 0.18 to 0.21 (mA/cm(2)), open-circuit voltage (VOC) from 0.24 to 0.55V, and fill factor from 0.34 to 0.39 were obtained for the DSSCs made using the working electrodes. The efficiency of the working electrodes after the addition of TBL was more than doubled. The light scattering and carrier transport properties of these composites promote the performance of dye-sensitized solar cells (DSSCs). Copyright © 2013 Elsevier B.V. All rights reserved.

The chemical bonds effect of anthocyanin and chlorophyll dyes on TiO2 for dye-sensitized solar cell (DSSC)

NASA Astrophysics Data System (ADS)

Ahliha, A. H.; Nurosyid, F.; Supriyanto, A.; Kusumaningsih, T.

2017-11-01

Anthocyanin and chlorophyll dyes have been blended as the photosensitizer of Dye-Sensitized Solar Cell (DSSC). The results study showed the effect of chemical bond dyes on TiO2 and the efficiency of DSSC. Ratio blend of the anthocyanin and chlorophyll dyes are 1:1. The absorbance of dyes and TiO2 were characterized using UV-Vis Spectrophotometer. The chemical bonds contained in TiO2-dyes were characterized using FT-IR spectrophotometer. The efficiency of DSSC was calculated using I-V meter. The absorption spectra of chlorophyll: anthocyanin blend dye solutions and TiO2 films can increase after the dye adsorption. Absorbance characterization of anthocyanin and chlorophyll dye blend solutions showed three peaks at the wavelength of 412 nm; 535.5 nm; and 656.5 nm. Absorbance characterization of spinach before being blend with anthocyanin dyes solutions showed two peaks at the wavelength of 431 nm and 665.5 nm. The absorption spectra of TiO2 films can increase after the dyes adsorption at the wavelength of 400 nm. FT-IR spectra of TiO2 founded the functional groups C-Br, C=C, and O-H. The functional groups founded in anthocyanin: chlorophyll dye blended on the surface of TiO2 are C-Br, C-O, O-H, C-H, C=C, C=O, and O-H. The result showed that the greatest efficiency of 0.0544% at dye red cabbage-spinach. Adsorption blends of anthocyanin and chlorophyll dyes on the surface of TiO2 can be used as the photosensitizer for DSSC.

Metal-free organic dyes for TiO2 and ZnO dye-sensitized solar cells

PubMed Central

Selopal, Gurpreet Singh; Wu, Hui-Ping; Lu, Jianfeng; Chang, Yu-Cheng; Wang, Mingkui; Vomiero, Alberto; Concina, Isabella; Diau, Eric Wei-Guang

2016-01-01

We report the synthesis and characterization of new metal-free organic dyes (namely B18, BTD-R, and CPTD-R) which designed with D-π-A concept to extending the light absorption region by strong conjugation group of π-linker part and applied as light harvester in dye sensitized solar cells (DSSCs). We compared the photovoltaic performance of these dyes in two different photoanodes: a standard TiO2 mesoporous photoanode and a ZnO photoanode composed of hierarchically assembled nanostructures. The results demonstrated that B18 dye has better photovoltaic properties compared to other two dyes (BTD-R and CPTD-R) and each dye has higher current density (Jsc) when applied to hierarchical ZnO nanocrystallites than the standard TiO2 mesoporous film. Transient photocurrent and photovoltage decay measurements (TCD/TVD) were applied to systematically study the charge transport and recombination kinetics in these devices, showing the electron life time (τR) of B18 dye in ZnO and TiO2 based DSSCs is higher than CPTD-R and BTD-R based DSSCs, which is consistent with the photovoltaic performances. The conversion efficiency in ZnO based DSSCs can be further boosted by 35%, when a compact ZnO blocking layer (BL) is applied to inhibit electron back reaction. PMID:26738698

Coumarin-indole conjugate donor-acceptor system: Synthesis, photophysical properties, anion sensing ability, theoretical and biological activity studies of two coumarin-indole based push-pull dyes

NASA Astrophysics Data System (ADS)

Aksungur, Tuğçe; Aydıner, Burcu; Seferoğlu, Nurgül; Özkütük, Müjgan; Arslan, Leyla; Reis, Yasemin; Açık, Leyla; Seferoğlu, Zeynel

2017-11-01

Two coumarin-indole conjugate fluorescent dyes having donor-acceptor-donor (D-A-D) (CI-1 and CI-2) were synthesized, and characterized using IR, 1H/13C NMR and HRMS. The absorption and emission properties of the dyes were determined in different solvents. The anion sensitivity and selectivity of the dyes were studied with some anions (CN-, F-, AcO-, Cl-, Br-, I-, HSO4- and H2PO4-) in DMSO, and their interaction mechanisms were evaluated by spectrophotometric and 1H NMR titration techniques. In addition, the molecular and electronic structures of CI-1, as well as the molecular complexes of CI-1, formed with the anions (F- and AcO-), were obtained theoretically and confirmed by DFT and TD-DFT calculations. CI-1 behaves as a colorimetric chemosensor for selective and sensitive detection of CN- in DMSO/H2O (9:1) over other competing anions such as F- and AcO-. However, only CN- interacts with chromophore CI-2 via Michael addition and the main absorption maxima shifts hypsochromically with an observed distinctive color change from orange to yellow. For using as a optic dye, the thermal stability properties of the dyes was determined by TGA (Thermal Gravimetric Analysis). Antimicrobial, antifungal and DNA-ligand interaction studies of the dyes were also examined. The dyes cause conformational changes on DNA and selectively bind to nucleotides of A/A and G/G.

Enhanced Photovoltaic Performances of Dye-Sensitized Solar Cells by Co-Sensitization of Benzothiadiazole and Squaraine-Based Dyes.

PubMed

Islam, Ashraful; Akhtaruzzaman, Md; Chowdhury, Towhid H; Qin, Chuanjiang; Han, Liyuan; Bedja, Idriss M; Stalder, Romain; Schanze, Kirk S; Reynolds, John R

2016-02-01

Dye-sensitized solar cells (DSSCs) based on a donor-acceptor-donor oligothienylene dye containing benzothiadiazole (T4BTD-A) were cosensitized with dyes containing cis-configured squaraine rings (HSQ3 and HSQ4). The cosensitized dyes showed incident monochromatic photon-to-current conversion efficiency (IPCE) greater than 70% in the 300-850 nm wavelength region. The individual overall conversion efficiencies of the sensitizers T4BTD-A, HSQ3, and HSQ4 were 6.4%, 4.8%, and 5.8%, respectively. Improved power conversion efficiencies of 7.0% and 7.7% were observed when T4BTD-A was cosensitized with HSQ3 and HSQ4, respectively, thanks to a significant increase in current density (JSC) for the cosensitized DSSCs. Intensity-modulated photovoltage spectroscopy results showed a longer lifetime for cosensitized T4BTD-A+HSQ3 and T4BTD-A+HSQ4 compared to that of HSQ3 and HSQ4, respectively.

Design of butterfly type organic dye sensitizers with double electron donors: The first principle study

NASA Astrophysics Data System (ADS)

Yang, Zhenqing; Shao, Di; Li, Juan; Tang, Lian; Shao, Changjin

2018-05-01

In this work, we designed a series of butterfly type organic dyes, named ME07-ME13 by introducing such as triphenylamine, phenothiazine, coumarin groups etc. as electron donors and further investigated their absorption spectra using density functional theory (DFT) and time-dependent DFT (TDDFT). All designed dyes cover the entire visible absorption spectrum from 300 to 800 nm. It's fascinating that ME13 molecule has two absorption peak and the molar coefficient of two absorption peaks are above 4.645 × 104 M-1·cm-1. The light absorption area of ME13 exhibits an increment of 16.5-19.1% compared to ME07-ME12. Furthermore, we performed a detailed analysis on their geometrical and electronic properties, including molecular structures, energy levels, light harvesting efficiency (LHE), driving force (ΔGinject), regeneration (ΔGregen),electron dipole moments (μnormal), intermolecular electron transfer and dye/(TiO2)38 system electron transitions. The results of calculation reveal that double coumarin donors in ME13 are promising functional groups for butterfly type organic dye sensitizers. It is expected that the design of double donors can provide a new strategy and guidance for the investigation in high efficiency dye-sensitized devices.

Fabrication, Optimization and Characterization of Natural Dye Sensitized Solar Cell

PubMed Central

Ghann, William; Kang, Hyeonggon; Sheikh, Tajbik; Yadav, Sunil; Chavez-Gil, Tulio; Nesbitt, Fred; Uddin, Jamal

2017-01-01

The dyes extracted from pomegranate and berry fruits were successfully used in the fabrication of natural dye sensitized solar cells (NDSSC). The morphology, porosity, surface roughness, thickness, absorption and emission characteristics of the pomegranate dye sensitized photo-anode were studied using various analytical techniques including FESEM, EDS, TEM, AFM, FTIR, Raman, Fluorescence and Absorption Spectroscopy. Pomegranate dye extract has been shown to contain anthocyanin which is an excellent light harvesting pigment needed for the generation of charge carriers for the production of electricity. The solar cell’s photovoltic performance in terms of efficiency, voltage, and current was tested with a standard illumination of air-mass 1.5 global (AM 1.5 G) having an irradiance of 100 mW/cm2. After optimization of the photo-anode and counter electrode, a photoelectric conversion efficiency (η) of 2%, an open-circuit voltage (Voc) of 0.39 mV, and a short-circuit current density (Isc) of 12.2 mA/cm2 were obtained. Impedance determination showed a relatively low charge-transfer resistance (17.44 Ω) and a long lifetime, signifying a reduction in recombination losses. The relatively enhanced efficiency is attributable in part to the use of a highly concentrated pomegranate dye, graphite counter electrode and TiCl4 treatment of the photo-anode. PMID:28128369

Fabrication, Optimization and Characterization of Natural Dye Sensitized Solar Cell

NASA Astrophysics Data System (ADS)

Ghann, William; Kang, Hyeonggon; Sheikh, Tajbik; Yadav, Sunil; Chavez-Gil, Tulio; Nesbitt, Fred; Uddin, Jamal

2017-01-01

The dyes extracted from pomegranate and berry fruits were successfully used in the fabrication of natural dye sensitized solar cells (NDSSC). The morphology, porosity, surface roughness, thickness, absorption and emission characteristics of the pomegranate dye sensitized photo-anode were studied using various analytical techniques including FESEM, EDS, TEM, AFM, FTIR, Raman, Fluorescence and Absorption Spectroscopy. Pomegranate dye extract has been shown to contain anthocyanin which is an excellent light harvesting pigment needed for the generation of charge carriers for the production of electricity. The solar cell’s photovoltic performance in terms of efficiency, voltage, and current was tested with a standard illumination of air-mass 1.5 global (AM 1.5 G) having an irradiance of 100 mW/cm2. After optimization of the photo-anode and counter electrode, a photoelectric conversion efficiency (η) of 2%, an open-circuit voltage (Voc) of 0.39 mV, and a short-circuit current density (Isc) of 12.2 mA/cm2 were obtained. Impedance determination showed a relatively low charge-transfer resistance (17.44 Ω) and a long lifetime, signifying a reduction in recombination losses. The relatively enhanced efficiency is attributable in part to the use of a highly concentrated pomegranate dye, graphite counter electrode and TiCl4 treatment of the photo-anode.

Template-free hydrothermal synthesis of beaded nanochain bundles of ZnO and their application as photoanode in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Ballal, Reshma; Shinde, Manish; Waghadkar, Yogesh; Arbuj, Sudhir; Rane, Sunit; Chauhan, Ratna

2018-02-01

ZnO shows promising candidature as photoanode material for dye-sensitized solar cells (DSSCs) due to its high bulk electron mobility and easily tailorable geometrical structures. The objective of this study is to facilitate the development of highly porous hierarchical ZnO for enhanced power conversion efficiency in dye-sensitized solar cells (DSSC) due to its greater dye adsorption. This study investigated the influence of reaction temperatures of 120 °C (sample Z-1) and 180 °C (sample Z-2) in hydrothermal synthesis on structural, morphological and optical properties of resultant ZnO nanostructures and their performance as photoanode material in DSSCs. The synthesized beaded nanochain bundles of ZnO, with multilayered and highly ordered texture, have diameters of several micrometers. Structural and morphological analysis shows that the ZnO beaded nanochain-like architectures possess wurtzite crystalline nature. These morphological improvements (beaded nanochains) of ZnO were found to exhibit higher dye loading and conversion efficiency due to increase in the surface area while reducing charge recombination. The maximum conversion efficiency was obtained with Z-1 and Z-2 is 2.95 and 3.56% with photocurrent of 7.73 and 9.24 mA/cm2, respectively. The obtained results pertaining to the DSSC performance studies were corroborated by the impedance spectroscopy data.

Survey of sensitizing components of oxidative hair dyes (retail and professional products) in Germany.

PubMed

Kirchlechner, Stephan; Hübner, Anja; Uter, Wolfgang

2016-07-01

Components of oxidative hair dyes, such as p-toluylenediamine, are very potent contact sensitizers to which many consumers as well as hairdressers and their clients are commonly exposed. Based on the qualitative composition of both retail and professional haircare products as determined by package labeling (according to INCI), we conducted a survey on the exposure to active components of oxidative hair dyes in Germany. The joint occurrence of components is also discussed. Nearly all of the 20 most commonly used substances are potent or very potent contact sensitizers. Contained in 88 % of all products, p-toluylenediamine is the most common component. There are only minor differences between retail and professional products. A frequent combination of substances includes p-toluylenediamine (sulfate), resorcinol as well as m-aminophenol. However, their actual concentrations (which were not investigated in this study) may vastly differ depending on the shade of the individual hair dye. Descriptive univariate analysis reveals that the currently used patch test series "Hairdressing Chemicals", as recommended by the German Contact Allergy Research Group (DKG), does not adequately cover the spectrum of allergens consumers and professionals are exposed to. Other studies have also suggested that a number of other allergens should be tested as well. Taking into account the dynamic kinetics of oxidative hair dyes with respect to allergy development, the effects of combined simultaneous exposure to multiple allergens on the risk of sensitization requires further research. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

Callindra haematocephata and Peltophorum pterocarpum flowers as natural sensitizers for TiO2 thin film based dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Maurya, Ishwar Chandra; Neetu; Gupta, Arun Kumar; Srivastava, Pankaj; Bahadur, Lal

2016-10-01

We have studied the performance of dye-sensitized solar cells employing natural dye extracted from the flowers Callindra haematocephata and Peltophorum pterocarpum as sensitizers for TiO2 photoanode. The extracts have shown appreciable absorption in the visible region. FTIR studies indicated the presence of anthocyanins and β-carotene in the flowers of C. haematocephata and P. pterocarpum respectively. The extracts were anchored on TiO2 film deposited on transparent conductive glass (FTO) which were used as photoanode. The dye coated TiO2 film electrode, Pt counter electrode and electrolyte (I-3) assembled into a cell module was illuminated by a light source with intensity 100 mW/cm2 to measure the photoelectric conversion efficiency of the DSSCs. From the J-V characteristic curves of cells, the parameters related to the solar cell performance were determined. The conversion efficiency of the DSSC employing natural dye extract from the flower C. haematocephata and P. pterocarpumwere was found as 0.06% and 0.04%, with open-circuit voltage (VOC) of 370 mV & 400 mV, short-circuit current density (JSC) of 0.25 mA/cm2 & 0.15 mA/cm2, fill factor (FF) of 0.70 & 0.71 and Pmax of 65 & 45 μW cm-2 respectively. The extract of the flower C. haematocephata exhibited better photosensitization action compared to the flower of P. pterocarpum.

Synthesis and characterization of Allium cepa L. as photosensitizer of dye-sensitized solar cell

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

Sutikno, E-mail: smadnasri@yahoo.com; Afrian, Noverdi; Supriadi,

The synthesis and characterization of Allium cepa L. used as natural pigment for natural dye sensitizer of solar cell has successfully done and anthocyanin is extracted. Anthocynin is color pigment of plant which has characteristic absorption spectrum of photon and excites electrons up to pigment molecules. As the anthocyanin absorbed light increases the excited electrons increase as well. The generated current also increases and it leads to the efficiency increase. The energy conversion efficiency of the cells sensitized with dye of Allium cepa L. was 3,045 x 10{sup −4}%. A simple technique was taken to fabricate dye sensitizer solar cellmore » is spincoating.« less

Synthesis of MSnO{sub 3} (M = Ba, Sr) nanoparticles by reverse micelle method and particle size distribution analysis by whole powder pattern modeling

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

Ahmed, Jahangeer; Blakely, Colin K.; Bruno, Shaun R.

2012-09-15

Highlights: ► BaSnO{sub 3} and SrSnO{sub 3} nanoparticles synthesized using the reverse micelle method. ► Particle size and size distribution studied by whole powder pattern modeling. ► Nanoparticles are of optimal size for investigation in dye-sensitized solar cells. -- Abstract: Light-to-electricity conversion efficiency in dye-sensitized solar cells critically depends not only on the dye molecule, semiconducting material and redox shuttle selection but also on the particle size and particle size distribution of the semiconducting photoanode. In this study, nanocrystalline BaSnO{sub 3} and SrSnO{sub 3} particles have been synthesized using the microemulsion method. Particle size distribution was studied by whole powdermore » pattern modeling which confirmed narrow particle size distribution with an average size of 18.4 ± 8.3 nm for SrSnO{sub 3} and 15.8 ± 4.2 nm for BaSnO{sub 3}. These values are in close agreement with results of transmission electron microscopy. The prepared materials have optimal microstructure for successive investigation in dye-sensitized solar cells.« less

Rapid Dye Regeneration Mechanism of Dye-Sensitized Solar Cells.

PubMed

Jeon, Jiwon; Park, Young Choon; Han, Sang Soo; Goddard, William A; Lee, Yoon Sup; Kim, Hyungjun

2014-12-18

During the light-harvesting process of dye-sensitized solar cells (DSSCs), the hole localized on the dye after the charge separation yields an oxidized dye, D(+). The fast regeneration of D(+) using the redox pair (typically the I(-)/I3(-) couple) is critical for the efficient DSSCs. However, the kinetic processes of dye regeneration remain uncertain, still promoting vigorous debates. Here, we use molecular dynamics simulations to determine that the inner-sphere electron-transfer pathway provides a rapid dye regeneration route of ∼4 ps, where penetration of I(-) next to D(+) enables an immediate electron transfer, forming a kinetic barrier. This explains the recently reported ultrafast dye regeneration rate of a few picoseconds determined experimentally. We expect that our MD based comprehensive understanding of the dye regeneration mechanism will provide a helpful guideline in designing TiO2-dye-electrolyte interfacial systems for better performing DSSCs.

Enhancing the power conversion efficiency of dye-sensitized solar cells via molecular plasmon-like excitations.

PubMed

Li, Jian-Hao; Gryn'ova, Ganna; Prlj, Antonio; Corminboeuf, Clémence

2017-02-21

We introduce a tactic for employing molecular plasmon-like excitations to enhance solar-to-electric power conversion efficiency of dye-sensitized solar cells. We offer general design principles of dimeric dyes, in which a strong plasmonic interaction between two π-conjugated moieties is promoted. The π-stacked conformations of these dimeric dyes result in a desirable broadened absorption and a longer absorption onset wavelength.

Metal-free and Oxygen-free Graphene as Oxygen Reduction Catalysts for Highly Efficient Fuel Cells

DTIC Science & Technology

2013-06-30

electrocatalysts for ORR in fuel cells and other applications, including dye-sensitized solar cells (DSSCs). Introduction Instead of burning...fuel cells and other applications, including dye-sensitized solar cells (DSSCs). 15. SUBJECT TERMS nano materials, nano science and technology...dye sensitized solar cells (DSSCs) have attracted much attention since Oregan and Grätzel’s seminal report in 1991. A typical DSSC device consists

Comparative sensitizing potencies of fragrances, preservatives, and hair dyes.

PubMed

Lidén, Carola; Yazar, Kerem; Johansen, Jeanne D; Karlberg, Ann-Therese; Uter, Wolfgang; White, Ian R

2016-11-01

The local lymph node assay (LLNA) is used for assessing sensitizing potential in hazard identification and risk assessment for regulatory purposes. Sensitizing potency on the basis of the LLNA is categorized into extreme (EC3 value of ≤0.2%), strong (>0.2% to ≤2%), and moderate (>2%). To compare the sensitizing potencies of fragrance substances, preservatives, and hair dye substances, which are skin sensitizers that frequently come into contact with the skin of consumers and workers, LLNA results and EC3 values for 72 fragrance substances, 25 preservatives and 107 hair dye substances were obtained from two published compilations of LLNA data and opinions by the Scientific Committee on Consumer Safety and its predecessors. The median EC3 values of fragrances (n = 61), preservatives (n = 19) and hair dyes (n = 59) were 5.9%, 0.9%, and 1.3%, respectively. The majority of sensitizing preservatives and hair dyes are thus strong or extreme sensitizers (EC3 value of ≤2%), and fragrances are mostly moderate sensitizers. Although fragrances are typically moderate sensitizers, they are among the most frequent causes of contact allergy. This indicates that factors other than potency need to be addressed more rigorously in risk assessment and risk management. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Experimental elaboration and analysis of dye-sensitized TiO2 solar cells (DSSC) dyed by natural dyes and conductive polymers

NASA Astrophysics Data System (ADS)

KałuŻyński, P.; Maciak, E.; Herzog, T.; Wójcik, M.

2016-09-01

In this paper we propose low cost and easy in development fully working dye-sensitized solar cell module made with use of a different sensitizing dyes (various anthocyanins and P3HT) for increasing the absorption spectrum, transparent conducting substrates (vaccum spattered chromium and gold), nanometer sized TiO2 film, iodide and methyl viologen dichloride based electrolyte, and a counter electrode (vaccum spattered platinum or carbon). Moreover, some of the different technologies and optimization manufacturing processes were elaborated for energy efficiency increase and were presented in this paper.

Electronic structure of dye-sensitized TiO2 clusters from many-body perturbation theory

NASA Astrophysics Data System (ADS)

Marom, Noa; Moussa, Jonathan E.; Ren, Xinguo; Tkatchenko, Alexandre; Chelikowsky, James R.

2011-12-01

The development of new types of solar cells is driven by the need for clean and sustainable energy. In this respect dye-sensitized solar cells (DSC) are considered as a promising route for departing from the traditional solid state cells. The physical insight provided by computational modeling may help develop improved DSCs. To this end, it is important to obtain an accurate description of the electronic structure, including the fundamental gaps and level alignment at the dye-TiO2 interface. This requires a treatment beyond ground-state density functional theory (DFT). We present a many-body perturbation theory study, within the G0W0 approximation, of two of the crystalline phases of dye-sensitized TiO2 clusters, reported by Benedict and Coppens, [J. Am. Chem. Soc.JACSAT0002-786310.1021/ja909600w 132, 2938 (2010)]. We obtain geometries in good agreement with the experiment by using DFT with the Tkatchenko-Scheffler van der Waals correction. We demonstrate that even when DFT gives a good description of the valence spectrum and a qualitatively correct picture of the electronic structure of the dye-TiO2 interface, G0W0 calculations yield more valuable quantitative information regarding the fundamental gaps and level alignment. In addition, we systematically investigate the issues pertaining to G0W0 calculations, namely: (i) convergence with respect to the number of basis functions, (ii) dependence on the mean-field starting point, and (iii) the validity of the assumption that the DFT wave function is a good approximation to the quasiparticle wave function. We show how these issues are manifested for dye molecules and for dye-sensitized TiO2 clusters.

Piper Ornatum and Piper Betle as Organic Dyes for TiO2 and SnO2 Dye Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Hayat, Azwar; Putra, A. Erwin E.; Amaliyah, Novriany; Hayase, Shuzi; Pandey, Shyam. S.

2018-03-01

Dye sensitized solar cell (DSSC) mimics the principle of natural photosynthesis are now currently investigated due to low manufacturing cost as compared to silicon based solar cells. In this report, we utilized Piper ornatum (PO) and Piper betle (PB) as sensitizer to fabricate low cost DSSCs. We compared the photovoltaic performance of both sensitizers with Titanium dioxide (TiO2) and Tin dioxide (SnO2) semiconductors. The results show that PO and PB dyes have higher Short circuit current (Jsc) when applied in SnO2 compared to standard TiO2 photo-anode film even though the Open circuit voltage (Voc) was hampered on SnO2 device. In conclusion, from the result, higher electron injections can be achieved by choosing appropriate semiconductors with band gap that match with dyes energy level as one of strategy for further low cost solar cell.

Green grasses as light harvesters in dye sensitized solar cells.

PubMed

Shanmugam, Vinoth; Manoharan, Subbaiah; Sharafali, A; Anandan, Sambandam; Murugan, Ramaswamy

2015-01-25

Chlorophylls, the major pigments presented in plants are responsible for the process of photosynthesis. The working principle of dye sensitized solar cell (DSSC) is analogous to natural photosynthesis in light-harvesting and charge separation. In a similar way, natural dyes extracted from three types of grasses viz. Hierochloe Odorata (HO), Torulinium Odoratum (TO) and Dactyloctenium Aegyptium (DA) were used as light harvesters in dye sensitized solar cells (DSSCs). The UV-Vis absorption spectroscopy, Fourier transform infrared (FT-IR), and liquid chromatography-mass spectrometry (LC-MS) were used to characterize the dyes. The electron transport mechanism and internal resistance of the DSSCs were investigated by the electrochemical impedance spectroscopy (EIS). The performance of the cells fabricated with the grass extract shows comparable efficiencies with the reported natural dyes. Among the three types of grasses, the DSSC fabricated with the dye extracted from Hierochloe Odorata (HO) exhibited the maximum efficiency. LC-MS investigations indicated that the dominant pigment present in HO dye was pheophytin a (Pheo a). Copyright © 2014 Elsevier B.V. All rights reserved.

Investigating the effect of various extracting solvents on the potential use of red-apple skin (Malus domestica) as natural sensitizer for dye-sensitized solar cell

NASA Astrophysics Data System (ADS)

Saputro, Aldhi; Mizan, Adlan; Sofyan, Nofrijon; Yuwono, Akhmad Herman

2017-03-01

In the current investigation, the natural dye extracted from red-apple (Malus domestica) skin was used as natural sensitizer for dye sensitized solar cell (DSSC) application. The present study was specifically aimed at observing the effect of different solvents, i.e. deionized water, ethanol, and acidified ethanol, on the performance of the natural dye and thus the DSSC. For synthesis purposes, red-apple skin was peeled off, dried, crushed and furthermore extracted with ratio red-apple skin powder to solvent 1:20 w/v for 2 hours at 50°C under mechanical stirring. Subsequently, the resulting natural dyes with different solvents were examined by Fourier transform infrared (FTIR) to analyze their functional groups, UV-Vis spectroscopy to observe their absorption spectra for a wide range of wavelength, while TiO2 nanoparticle used as the semiconductor oxide layer in the device was characterized by field emission scanning electron microscope (FESEM). The FTIR results showed that the red-apple skin has anthocyanin group which functions as the sensitizer agent for photon energy absorption from the sunlight. The UV-Vis spectroscopy results showed that ethanol solvent has higher absorption of sunlight wavelength as compared to those of deionized water and acidified ethanol solvents. The performance test of the fabricated DSSC showed the prototype made of the red apple skin dye extracted by ethanol solvent can provide the highest open circuit voltage (Voc) up to 324 mV and efficiency around 0.046%. On the basis of investigation, it has been found that ethanol was the best solvent to extract anthocyanin from the red-apple skin.

Design of organic dyes and cobalt polypyridine redox mediators for high-efficiency dye-sensitized solar cells.

PubMed

Feldt, Sandra M; Gibson, Elizabeth A; Gabrielsson, Erik; Sun, Licheng; Boschloo, Gerrit; Hagfeldt, Anders

2010-11-24

Dye-sensitized solar cells (DSCs) with cobalt-based mediators with efficiencies surpassing the record for DSCs with iodide-free electrolytes were developed by selecting a suitable combination of a cobalt polypyridine complex and an organic sensitizer. The effect of the steric properties of two triphenylamine-based organic sensitizers and a series of cobalt polypyridine redox mediators on the overall device performance in DSCs as well as on transport and recombination processes in these devices was compared. The recombination and mass-transport limitations that, previously, have been found to limit the performance of these mediators were avoided by matching the properties of the dye and the cobalt redox mediator. Organic dyes with higher extinction coefficients than the standard ruthenium sensitizers were employed in DSCs in combination with outer-sphere redox mediators, enabling thinner TiO(2) films to be used. Recombination was reduced further by introducing insulating butoxyl chains on the dye rather than on the cobalt redox mediator, enabling redox couples with higher diffusion coefficients and more suitable redox potential to be used, simultaneously improving the photocurrent and photovoltage of the device. Optimization of DSCs sensitized with a triphenylamine-based organic dye in combination with tris(2,2'-bipyridyl)cobalt(II/III) yielded solar cells with overall conversion efficiencies of 6.7% and open-circuit potentials of more than 0.9 V under 1000 W m(-2) AM1.5 G illumination. Excellent performance was also found under low light intensity indoor conditions.

Visible to near infra red absorption in natural dye (Mondo Grass Berry) for Dye Sensitized Solar Cell

NASA Astrophysics Data System (ADS)

Pitigala, Duleepa; Desilva, L. A. A.; Perera, A. G. U.

2012-03-01

The development of dye sensitized solar cells (DSSC) is an exciting field in the low cost renewable energy production. Two major draw backs in the DSSCs are the narrow spectral response and the short term stability. Research on development of artificial dyes for broadening the response is important in finding a solution. Work presented here shows a broad spectral response with a natural dye extracted from a Mondo Grass berry (Ophiopogonjaponicus).The dye is extracted by crushing the berries and filtering to remove the pulp. A DSSC sensitized with Mondo Grass dye, and with TiO2 film screen printed on a Florien doped Tin Oxide (FTO) glass and baked for 30 minutes at 450 C as the working electrode and Iodine/triiodide red-ox electrolyte as the hole collector was tested for its performance. An open circuit photovoltage of 495 mV and a short circuit photocurrent of 0.6 mA/cm2were observed under a simulated lamp equivalent to 1 sun illumination. The broad spectral response from 400 nm to 750 nm was also observed for the Mondo Grass dye compared to other natural dyes consists of anthocyanins or tannins.

Dye molecular structure device open-circuit voltage correlation in Ru(II) sensitizers with heteroleptic tridentate chelates for dye-sensitized solar cells.

PubMed

Wu, Kuan-Lin; Li, Cheng-Hsuan; Chi, Yun; Clifford, John N; Cabau, Lydia; Palomares, Emilio; Cheng, Yi-Ming; Pan, Hsiao-An; Chou, Pi-Tai

2012-05-02

Dicarboxyterpyridine chelates with π-conjugated pendant groups attached at the 5- or 6-position of the terminal pyridyl unit were synthesized. Together with 2,6-bis(5-pyrazolyl)pyridine, these were used successfully to prepare a series of novel heteroleptic, bis-tridentate Ru(II) sensitizers, denoted as TF-11-14. These dyes show excellent performance in dye-sensitized solar cells (DSCs) under AM1.5G simulated sunlight at a light intensity of 100 mW cm(-2) in comparison with a reference device containing [Ru(Htctpy)(NCS)(3)][TBA](3) (N749), where H(3)tctpy and TBA are 4,4',4"-tricarboxy-2,2':6',2"-terpyridine and tetra-n-butylammonium cation, respectively. In particular, the sensitizer TF-12 gave a short-circuit photocurrent of 19.0 mA cm(-2), an open-circuit voltage (V(OC)) of 0.71 V, and a fill factor of 0.68, affording an overall conversion efficiency of 9.21%. The increased conjugation conferred to the TF dyes by the addition of the π-conjugated pendant groups increases both their light-harvesting and photovoltaic energy conversion capability in comparison with N749. Detailed recombination processes in these devices were probed by various spectroscopic and dynamics measurements, and a clear correlation between the device V(OC) and the cell electron lifetime was established. In agreement with several other recent studies, the results demonstrate that high efficiencies can also be achieved with Ru(II) sensitizers that do not contain thiocyanate ancillaries. This bis-tridentate, dual-carboxy anchor configuration thus serves as a prototype for future omnibearing design of highly efficient Ru(II) sensitizers suited for use in DSCs. © 2012 American Chemical Society

Synthesis of zinc chlorophyll materials for dye-sensitized solar cell applications

NASA Astrophysics Data System (ADS)

Erten-Ela, Sule; Vakuliuk, Olena; Tarnowska, Anna; Ocakoglu, Kasim; Gryko, Daniel T.

2015-01-01

To design sensitizers for dye sensitized solar cells (DSSCs), a series of zinc chlorins with different substituents were synthesized. Novel zinc methyl 3-devinyl-3-hydroxymethyl-20-phenylacetylenylpyropheophorbide-a (ZnChl-1), zinc methyl 20-bromo-3-devinyl-3-hydroxymethylpyropheophorbide-a (ZnChl-2), zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-3), zinc propyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (ZnChl-4) were synthesized and their photovoltaic performances were evaluated in dye-sensitized solar cells. Photoelectrodes with a 7 μm thick nanoporous layer and a 5 μm thick light-scattering layer were used to fabricate dye sensitized solar cells. The best efficiency was obtained with ZnChl-2 sensitizer. ZnChl-2 gave a Jsc of 3.5 mA/cm2, Voc of 412 mV, FF of 0.56 and an overall conversion efficiency of 0.81 at full sun (1000 W m-2).

Spectroscopic detection of halogen bonding resolves dye regeneration in the dye-sensitized solar cell.

PubMed

Parlane, Fraser G L; Mustoe, Chantal; Kellett, Cameron W; Simon, Sarah J; Swords, Wesley B; Meyer, Gerald J; Kennepohl, Pierre; Berlinguette, Curtis P

2017-11-24

The interactions between a surface-adsorbed dye and a soluble redox-active electrolyte species in the dye-sensitized solar cell has a significant impact on the rate of regeneration of photo-oxidized dye molecules and open-circuit voltage of the device. Dyes must therefore be designed to encourage these interfacial interactions, but experimentally resolving how such weak interactions affect electron transfer is challenging. Herein, we use X-ray absorption spectroscopy to confirm halogen bonding can exist at the dye-electrolyte interface. Using a known series of triphenylamine-based dyes bearing halogen substituents geometrically positioned for reaction with halides in solution, halogen bonding was detected only in cases where brominated and iodinated dyes were photo-oxidized. This result implies that weak intermolecular interactions between photo-oxidized dyes and the electrolyte can impact device photovoltages. This result was unexpected considering the low concentration of oxidized dyes (less than 1 in 100,000) under full solar illumination.

Temperature effect of natural organic extraction upon light absorbance in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Suhaimi, Suriati; Mohamed Siddick, Siti Zubaidah; Retnasamy, Vithyacharan; Abdul Wahid, Mohamad Halim; Ahmad Hambali, Nor Azura Malini; Mohamad Shahimin, Mukhzeer

2017-02-01

Natural organic dyes contain pigments which when safely extracted from plants have the potential to be used as a sensitizer while promising a low-cost fabrication, environmental friendly dye-sensitized solar cells (DSSCs). Ardisia, Bawang Sabrang, Harum Manis mango, Oxalis Triangularis and Rosella showed different absorption peaks when the extraction process were carried out at different temperatures. Hence, these were used as the basis to determine the conversion efficiency against the dyes extracting temperature. In this study, all dyes extracted in water have shown the best performance at a temperature of 100°C except for Harum Manis mango, while in ethanol, the optimum temperature was obtained between the room temperature, 25°C and 50°C. The absorption spectrum in water showed a broader absorption wavelength vis-à-vis ethanol solvent that resulted in the absorption peak for Ardisia, Harum Manis mango and Rosella between 450 nm and 550 nm. The highest conversion efficiency is observed to be achieved by Oxalis Triangularis extracted in water solution at 100°C, which was approximately 0.96% which corresponds to the broader absorbance trends in the literature. Thus, the optimum condition for extracting temperature for dyes in water and ethanol is room temperature and boiling points of water. Hence, Ardisia, Bawang Sabrang, Harum Manis mango, Oxalis Triangularis and Rosella can be an as alternative source for photosensitizer, and the impacts of temperature upon the light absorbance can be further investigated to produce the ultimate natural dye based solar cells.

Binaphthyl-containing Schiff base complexes with carboxyl groups for dye sensitized solar cell: An experimental and theoretical study

NASA Astrophysics Data System (ADS)

Tsaturyan, Arshak; Machida, Yosuke; Akitsu, Takashiro; Gozhikova, Inna; Shcherbakov, Igor

2018-06-01

We report on synthesis and characterization of binaphthyl containing Schiff base Ni(II), Cu(II), and Zn(II) complexes as promising photosensitizers for dye-sensitized solar cells (DSSC). Based on theoretical and experimental data, the possibility of their application in DSSC was confirmed. To our knowledge, we find dye performance of complex is steric and rigid structure widely spread to efficiency. The spatial and electronic structures of the complexes were studied by means of the quantum chemical modeling using DFT and TD-DFT approaches. The adsorption energies of the complexes on TiO2 cluster were calculated and appeared to be very close in value. The Zn(II) complex has the biggest value of molar extinction.

Characteristics of dye Rhoeo spathacea in dye sensitizer solar cell (DSSC)

NASA Astrophysics Data System (ADS)

Sumardiasih, Sri; Obina, Wilfrida M.; Cari; Supriyanto, Agus; Septiawan, Trio Y.; Khairuddin

2017-01-01

Dye-sensitized solar cell (DSSC) is a device that converts solar energy into electrical energy. The magnitude of the efficiency of DSSC is mainly based on the amount of dye absorbed by the surface of TiO2. In this work, used natural dye extracted from leaves Rhoeo spathacea. The dye partially used to immerse of TiO2 as working electrodes, and the rest are directly mixed TiO2 paste to obtain dye titanium dioxide.The paste TiO2 and dye titanium dioxide coated onto the fluorine-doped tin oxide (FTO) glass plate by spin coating method. The absorbance spectra of the dye, dye titanium dioxide and TiO2 were obtained by UV-Vis spectroscopy. The conductivity of the dye, dye titanium dioxide, and TiO2 was measured by two point probe El-Kahfi 100. The DSSC based on dye titanium dioxide that stirring for 5 hours the highest efficiency of 0,0520 % whereas those based on TiO2 immersed for 36 hours showed achieved 0,0501 % obtained from I-V characterization.

Dye-sensitized solar cells consisting of dye-bilayer structure stained with two dyes for harvesting light of wide range of wavelength

NASA Astrophysics Data System (ADS)

Inakazu, Fumi; Noma, Yusuke; Ogomi, Yuhei; Hayase, Shuzi

2008-09-01

Dye-sensitized solar cells (DSCs) containing dye-bilayer structure of black dye and NK3705 (3-carboxymethyl-5-[3-(4-sulfobutyl)-2(3H)-bezothiazolylidene]-2-thioxo-4-thiazolidinone, sodium salt) in one TiO2 layer (2-TiO-BD-NK) are reported. The 2-TiO-BD-NK structure was fabricated by staining one TiO2 layer with these two dyes, step by step, under a pressurized CO2 condition. The dye-bilayer structure was observed by using a confocal laser scanning microscope. The short circuit current (Jsc) and the incident photon to current efficiency of the cell (DSC-2-TiO-BD-NK) was almost the sum of those of DSC stained with black dye only (DSC-1-TiO-BD) and DSC stained with NK3705 only (DSC-1-TiO-NK).

Transforming Benzophenoxazine Laser Dyes into Chromophores for Dye-Sensitized Solar Cells: A Molecular Engineering Approach

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

Schröder, Florian A. Y. N.; Cole, Jacqueline M.; Waddell, Paul G.

2015-02-03

The re-functionalization of a series of four well-known industrial laser dyes, based on benzophenoxazine, is explored with the prospect of molecularly engineering new chromophores for dye-sensitized solar cell (DSC) applications. Such engineering is important since a lack of suitable dyes is stifling the progress of DSC technology. The conceptual idea involves making laser dyes DSC-active by chemical modification, while maintaining their key property attributes that are attractive to DSC applications. This molecular engineering follows a step-wise approach. Firstly, molecular structures and optical absorption properties are determined for the parent laser dyes: Cresyl Violet (1); Oxazine 170 (2); Nile Blue Amore » (3), Oxazine 750 (4). These reveal structure-property relationships which define the prerequisites for computational molecular design of DSC dyes; the nature of their molecular architecture (D-π-A) and intramolecular charge transfer. Secondly, new DSC dyes are computationally designed by the in silico addition of a carboxylic acid anchor at various chemical substitution points in the parent laser dyes. A comparison of the resulting frontier molecular orbital energy levels with the conduction band edge of a TiO2 DSC photoanode and the redox potential of two electrolyte options I-/I3- and Co(II/III)tris(bipyridyl) suggests promise for these computationally designed dyes as co-sensitizers for DSC applications.« less

Modulation of π-spacer of carbazole-carbazole based organic dyes toward high efficient dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Chitpakdee, Chirawat; Jungsuttiwong, Siriporn; Sudyoadsuk, Taweesak; Promarak, Vinich; Kungwan, Nawee; Namuangruk, Supawadee

2017-03-01

The effects of type and position of π-linker in carbazole-carbazole based dyes on their performance in dye-sensitized solar cells (DSSCs) were investigated by DFT and TDDFT methods. The calculated electronic energy level, electron density composition, charge injection and charge recombination properties were compared with those of the high performance CCT3A dye synthesized recently. It is found that that mixing a benzothiadizole (B) unit with two thiophene (T) units in the π-spacer can greatly shift absorption wavelength to near infrared region and enhance the light harvesting efficiency (LHE) resulting in increasing of short-circuit current density (Jsc), whereas a thienothiophene unit does not affect those properties. However, a B should be not directly connected to the anchoring group of the dye because it brings electrolyte to the TiO2 surface which may increase charge recombination rate and consequently decrease open circuit voltage (Voc). This work shows how type and position of the π-linker affect the performance of DSSCs, and how to modulate those properties. We predicted that the designed dye derived from insertion of the B unit in between the two T units would have higher performance than CCT3A dye. The insight understanding from this study is useful for further design of higher performance dyes by molecular engineering.

Impact of natural photosensitizer extraction solvent upon light absorbance in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Suhaimi, Suriati; Mohamed Siddick, Siti Zubaidah; Ahmad Hambali, Nor Azura Malini; Retnasamy, Vithyacharan; Abdul Wahid, Mohamad Halim; Mohamad Shahimin, Mukhzeer

2017-02-01

Natural pigmentations of Ardisia, Bawang Sabrang, Harum Manis mango, Oxalis Triangularis and Rosella were used to study the general trend in performance of dyes as a photosensitizer in the application of dye-sensitized solar cells (DSSCs) based on optical light absorbance and photoelectrochemical characteristics. From the Ultraviolet-Visible Spectrophotometer with the recorded absorption measurements in the range between 400 nm to 800 nm, the dyes extracted from Rosella and Oxalis Triangularis in water solvent exhibited the conversion efficiency up to 0.68% and 0.67%, respectively. The light absorbance peak for dye extracted from Ardisia, Bawang Sabrang, Oxalis Triangularis and Rosella in water and ethanol solvent resulted in the range between 500 nm to 650 nm, while the Harum Manis mango resulted in the broader spectra in both water and ethanol solvent. The light absorbance spectra of each the dyes shows shifted wavelength spectrum when the extracted dye is adsorbed onto TiO2 film surface that might influenced the absorption of light by TiO2 particle in the visible region. The capabilities of the dyes to absorb light when bonded onto the TiO2 photoanode was found to be significant with the current-voltage conversion of the cell. The results demonstrates just the tip of the vastness of natural dyes' (native to tropical region) feasibility and applicability as a photosensitizer.

Rational molecular engineering of cyclopentadithiophene-bridged D-A-π-A sensitizers combining high photovoltaic efficiency with rapid dye adsorption

PubMed Central

Chai, Qipeng; Li, Wenqin; Liu, Jingchuan; Geng, Zhiyuan; Tian, He; Zhu, Wei-hong

2015-01-01

Dye-sensitized solar cell (DSSC) is considered as a feasible route to the clean and renewable energy conversion technique. The commercial application requires further enhancements on photovoltaic efficiency and simplification on the device fabrication. For avoiding the unpreferable trade-off between photocurrent (JSC) and photovoltage (VOC), here we report the molecular engineering and comprehensive photovoltaic characterization of three cyclopentadithiophene-bridged D-A-π-A motif sensitizers with a change in donor group. We make a careful choice on the donor and conjugation bridge for synergistically increasing JSC and VOC. Comparing with the reference dye WS-2, the photovoltaic efficiency with the single component dye of WS-51 increases by 18%, among one of the rare examples in pure metal-free organic dyes exceeding 10% in combination with traditional iodine redox couples. Moreover, WS-51 exhibits several prominent merits on potentially scale-up industrial application: i) facile synthetic route to target molecule, ii) simple dipping procedure without requirement of co-sensitization, and iii) rapid dye adsorption capability. PMID:26066974

Transition Metal Polypyridine Complexes: Studies of Mediation in Dye-Sensitized Solar Cells and Charge Separation

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

Elliott, C. Michael; Prieto, Amy L.

2017-02-08

The Elliott group has long been supported by DOE for studies of cobalt(II/III) trisbypiridine (DTB) mediator complexes in dye sensitized solar cells. Previous work demonstrated that Co(II/III) chemistry is sensitive to the environment, showing unprecedented electrode-surface and electrolyte dependant voltammetry. In electrolytes that have large lipophilic cations, voltammetry of the [Co(DTB) 3] 2+/3+ couple is nearly Nernstian in appearance on nominally oxide-free metal surfaces. In contrast, on semiconductor electrodes in electrolytes with small, hard cations such as Li +, the electron transfer rates are so slow that it is difficult to measure any Faradaic current even at overpotentials of ±1more » V. These studies are of direct relevance to the operation of cobalt-based mediators in solar cells. The research has also shown that these mediators are compatible with copper phenantroline based dyes, in contrast to I - due to the insolubility of CuI.« less

Role of Co-Sensitizers in Dye-Sensitized Solar Cells.

PubMed

Krishna, Narra Vamsi; Krishna, Jonnadula Venkata Suman; Mrinalini, Madoori; Prasanthkumar, Seelam; Giribabu, Lingamallu

2017-12-08

Co-sensitization is a popular route towards improved efficiency and stability of dye-sensitized solar cells (DSSCs). In this context, the power conversion efficiency (PCE) values of DSSCs incorporating Ru- and porphyrin-based dyes can be improved from 8-11 % to 11-14 % after the addition of additives, co-adsorbents, and co-sensitizers that reduce aggregation and charge recombination in the device. Among the three supporting material types, co-sensitizers play a major role to enhance the performance and stability of DSSCs, which is requried for commercialization. In this Minireview, we highlight the role co-sensitizers play in improving photovoltaic performance of devices containing Ru- and porphyrin-based sensitizers. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rational Molecular Engineering of Indoline-Based D-A-π-A Organic Sensitizers for Long-Wavelength-Responsive Dye-Sensitized Solar Cells.

PubMed

Zhang, Weiwei; Wu, Yongzhen; Zhu, Haibo; Chai, Qipeng; Liu, Jingchuan; Li, Hui; Song, Xiongrong; Zhu, Wei-Hong

2015-12-09

Indoline-based D-A-π-A organic sensitizers are promising candidates for highly efficient and long-term stable dye-sensitized solar cells (DSSCs). In order to further broaden the spectral response of the known indoline dye WS-2, we rationally engineer the molecular structure through enhancing the electron donor and extending the π-bridge, resulting in two novel indoline-based D-A-π-A organic sensitizers WS-92 and WS-95. By replacing the 4-methylphenyl group on the indoline donor of WS-2 with a more electron-rich carbazole unit, the intramolecular charge transfer (ICT) absorption band of dye WS-92 is slightly red-shifted from 550 nm (WS-2) to 554 nm (WS-92). In comparison, the incorporation of a larger π-bridge of cyclopentadithiophene (CPDT) unit in dye WS-95 not only greatly bathochromatically tunes the absorption band to 574 nm but also largely enhances the molar extinction coefficients (ε), thus dramatically improving the light-harvesting capability. Under the standard global AM 1.5 solar light condition, the photovoltaic performances of both organic dyes have been evaluated in DSSCs on the basis of the iodide/triiodide electrolyte without any coadsorbent or cosensitizer. The DSSCs based on WS-95 display better device performance with power conversion efficiency (η) of 7.69%. The additional coadsorbent in the dye bath of WS-95 does not improve the photovoltaic performance, indicative of its negligible dye aggregation, which can be rationalized by the grafted dioctyl chains on the CPDT unit. The cosensitization of WS-95 with a short absorption wavelength dye S2 enhances the IPCE and improves the η to 9.18%. Our results indicate that extending the π-spacer is more rational than enhancing the electron donor in terms of broadening the spectral response of indoline-based D-A-π-A organic sensitizers.

Brown seaweed pigment as a dye source for photoelectrochemical solar cells

NASA Astrophysics Data System (ADS)

Calogero, Giuseppe; Citro, Ilaria; Di Marco, Gaetano; Armeli Minicante, Simona; Morabito, Marina; Genovese, Giuseppa

2014-01-01

Chlorophylls based-dyes obtained from seaweeds represent attractive alternatives to the expensive and polluting pyridil based Ru complexes because of their abundance in nature. Another important characteristic is that the algae do not subtract either cropland or agricultural water, therefore do not conflict with agro-food sector. This pigment shows a typical intense absorption in the UV/blue (Soret band) and a less intense band in the red/near IR (Q band) spectral regions and for these reasons appear very promising as sensitizer dyes for DSSC. In the present study, we utilized chlorophylls from samples of the brown alga Undaria pinnatifida as sensitizer in DSSCs. The dye, extracted by frozen seaweeds and used without any chemical purification, showed a very good fill factor (0.69). Even the photelectrochemical parameters if compared with the existent literature are very interesting.

Fabrication of dye-sensitized solar cell (DSSC) using annato seeds (Bixa orellana Linn)

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

Haryanto, Ditia Allindira; Landuma, Suarni; Purwanto, Agus

2014-02-24

The Fabrication of dye sensitized solar cell (DSSC) using Annato seeds has been conducted in this study. Annato seeds (Bixa orellana Linn) used as a sensitizer for dye sensitized solar cell. The experimental parameter was concentration of natural dye. Annato seeds was extracted using etanol solution and the concentration was controlled by varying mass of Annato seeds. A semiconductor TiO{sub 2} was prepared by a screen printing method for coating glass use paste of TiO{sub 2}. Construction DSSC used layered systems (sandwich) consists of working electrode (TiO{sub 2} semiconductor-dye) and counter electrode (platina). Both are placed on conductive glass andmore » electrolytes that occur electrons cycle. The characterization of thin layer of TiO{sub 2} was conducted using SEM (Scanning Electron Microscpy) analysis showed the surface morphology of TiO{sub 2} thin layer and the cross section of a thin layer of TiO{sub 2} with a thickness of 15–19 μm. Characterization of natural dye extract was determined using UV-Vis spectrometry analysis shows the wavelength range annato seeds is 328–515 nm, and the voltage (V{sub oc}) and electric current (I{sub sc}) resulted in keithley test for 30 gram, 40 gram, and 50 gram were 0,4000 V; 0,4251 V; 0,4502 V and 0,000074 A; 0,000458 A; 0,000857 A, respectively. The efficiencies of the fabricated solar cells using annato seeds as senstizer for each varying mass are 0,00799%, 0,01237%, and 0,05696%.« less

Dye-sensitized solar cells

DOEpatents

Skotheim, T.A.

1980-03-04

A low-cost dye-sensitized Schottky barrier solar cell is comprised of a substrate of semiconductor with an ohmic contact on one face, a sensitizing dye adsorbed onto the opposite face of the semiconductor, a transparent thin-film layer of a reducing agent over the dye, and a thin-film layer of metal over the reducing agent. The ohmic contact and metal layer constitute electrodes for connection to an external circuit and one or the other or both are made transparent to permit light to penetrate to the dye and be absorbed therein for generating electric current. The semiconductor material chosen to be the substrate is one having a wide bandgap and which therefore is transparent; the dye selected is one having a ground state within the bandgap of the semiconductor to generate carriers in the semiconductor, and a first excited state above the conduction band edge of the semiconductor to readily conduct electrons from the dye to the semiconductor; the reducing agent selected is one having a ground state above the ground state of the sensitizer to provide a plentiful source of electrons to the dye during current generation and thereby enhance the generation; and the metal for the thin-film layer of metal is selected to have a Fermi level in the vicinity of or above the ground state of the reducing agent to thereby amply supply electrons to the reducing agent. 3 figs.

Dye-sensitized solar cells

DOEpatents

Skotheim, Terje A. [Berkeley, CA

1980-03-04

A low-cost dye-sensitized Schottky barrier solar cell comprised of a substrate of semiconductor with an ohmic contact on one face, a sensitizing dye adsorbed onto the opposite face of the semiconductor, a transparent thin-film layer of a reducing agent over the dye, and a thin-film layer of metal over the reducing agent. The ohmic contact and metal layer constitute electrodes for connection to an external circuit and one or the other or both are made transparent to permit light to penetrate to the dye and be absorbed therein for generating electric current. The semiconductor material chosen to be the substrate is one having a wide bandgap and which therefore is transparent; the dye selected is one having a ground state within the bandgap of the semiconductor to generate carriers in the semiconductor, and a first excited state above the conduction band edge of the semiconductor to readily conduct electrons from the dye to the semiconductor; the reducing agent selected is one having a ground state above the ground state of the sensitizer to provide a plentiful source of electrons to the dye during current generation and thereby enhance the generation; and the metal for the thin-film layer of metal is selected to have a Fermi level in the vicinity of or above the ground state of the reducing agent to thereby amply supply electrons to the reducing agent.

Dye-sensitized Schottky barrier solar cells

DOEpatents

Skotheim, Terje A.

1978-01-01

A low-cost dye-sensitized Schottky barrier solar cell comprised of a substrate of semiconductor with an ohmic contact on one face, a sensitizing dye adsorbed onto the opposite face of the semiconductor, a transparent thin-film layer of a reducing agent over the dye, and a thin-film layer of metal over the reducing agent. The ohmic contact and metal layer constitute electrodes for connection to an external circuit and one or the other or both are made transparent to permit light to penetrate to the dye and be absorbed therein for generating electric current. The semiconductor material chosen to be the substrate is one having a wide bandgap and which therefore is transparent; the dye selected is one having a ground state within the bandgap of the semiconductor to generate carriers in the semiconductor, and a first excited state above the conduction band edge of the semiconductor to readily conduct electrons from the dye to the semiconductor; the reducing agent selected is one having a ground state above the ground state of the sensitizer to provide a plentiful source of electrons to the dye during current generation and thereby enhance the generation; and the metal for the thin-film layer of metal is selected to have a Fermi level in the vicinity of or above the ground state of the reducing agent to thereby amply supply electrons to the reducing agent.

Fabrication and characterization of mixed dye: Natural and synthetic organic dye

NASA Astrophysics Data System (ADS)

Richhariya, Geetam; Kumar, Anil

2018-05-01

Mixed dye from hibiscus sabdariffa and eosin Y was employed in the fabrication of dye sensitized solar cell (DSSC). Nanostructured mesoporous film was prepared from the titanium dioxide (TiO2). The energy conversion efficiency of hibiscus, eosin Y and mixed dye was obtained as 0.41%, 1.53% and 2.02% respectively. Mixed DSSC has shown improvement in the performance of the cell as compared to hibiscus and eosin Y dye due to addition of synthetic organic dye. This illustrates the effect of synthetic organic dyes in performance enhancement of natural dyes. It has been credited to the improved absorption of light mainly in higher energy state (λ = 440-560 nm) when two dyes were employed simultaneously as was obvious from the absorption spectra of dyes adsorbed onto TiO2 electrode. The cell with TiO2 electrode sensitized by mixed dye gives short circuit current density (Jsc) = 4.01 mA/cm2, open circuit voltage (Voc) = 0.67 V, fill factor (FF) = 0.60 and energy conversion efficiency (η) of 2.02%.

Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane

PubMed Central

Khan, Md. Rajibur Rahaman; Khalilian, Alireza; Kang, Shin-Won

2016-01-01

In this paper, we proposed an interdigitated capacitor (IDC)-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt’s dye (R-dye). These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC)] and N,N-Dimethylacetamide (DMAC) solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE) by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance. PMID:26907291

Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane.

PubMed

Khan, Md Rajibur Rahaman; Khalilian, Alireza; Kang, Shin-Won

2016-02-20

In this paper, we proposed an interdigitated capacitor (IDC)-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt's dye (R-dye). These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC)] and N,N-Dimethylacetamide (DMAC) solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE) by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance.

Tuning the physical properties of organic sensitizers by replacing triphenylamine with new donors for dye sensitized solar cells - a theoretical approach.

PubMed

Ramkumar, Sekar; Manidurai, Paulraj

2017-02-15

New donor molecules with low ionization potential have been theoretically designed by replacing the benzene moieties in triphenylamine (TPA) with thiophene as well as furan. The designed new donors also exhibited planar structure, making an angle of 120° around the nitrogen atom that results in resonance effects through π-bonds of aryl rings. New sensitizers have been theoretically studied using DFT and TD-DFT by adopting these designed donors. UV-Vis absorption spectra, light harvesting ability (LHE) and electron injection ability (ΔG inject ) of the designed sensitizers have been calculated by taking L0 as reference. Orbital overlapping between donor and acceptor facilitates intra-molecular charge transfer, thereby increasing the interfacial electron injection from the sensitizer to the semiconductor nanoparticles. Our theoretical results demonstrate that sensitizers DTPA-AA and DFPA-AA have broader absorption and lower ΔG inject respectively compare to L0, this opens a new way for designing sensitizers for dye sensitized solar cells (DSSCs). All the dyes designed were found to be good light harvesters. Copyright © 2016 Elsevier B.V. All rights reserved.

pH-Assisted control over the binding and relocation of an acridine guest between a macrocyclic nanocarrier and natural DNA.

PubMed

Sayed, Mhejabeen; Pal, Haridas

2015-04-14

The differential binding affinity of the hydroxypropyl-β-cyclodextrin (HPβCD) macrocycle, a drug delivery vehicle, towards the protonated and deprotonated forms of the well-known DNA binder and model anticancer drug acridine has been exploited as a strategy for dye-drug transportation and pH-responsive delivery to a natural DNA target. From pH-sensitive changes in the ground state absorption and steady-state fluorescence characteristics of the studied acridine dye-HPβCD-DNA ternary system and strongly supported by fluorescence lifetime, fluorescence anisotropy, Job's plots, (1)H NMR and circular dichroism results, it is revealed that in a moderately alkaline solution (pH ∼ 8.5), the dye can be predominantly bound to the HPβCD macrocycle and when the pH is lowered to a moderately acidic region (pH ∼ 4), the dye efficiently detaches from the HPβCD cavity and almost exclusively binds to DNA. In the present study we are thus able to construct a pH-sensitive supramolecular assembly where pH acts as a simple stimulus for controlled uptake and targeted release of the dye-drug. As pH is an essential and sensitive factor in various biological processes, a simple yet reliable pH-sensitive model such as is demonstrated here can have promising applications in the host-assisted delivery of prodrug to the target sites, such as cancer or tumour microenvironments, with an enhanced stability, bioavailability and activity, and also in the design of new fluorescent probes, sensors and smart materials for applications in nano-science.

Enhanced photoresponse in dye-sensitized solar cells via localized surface plasmon resonance through highly stable nickel nanoparticles

NASA Astrophysics Data System (ADS)

Rahman, Md. Mahbubur; Im, Sang Hyuk; Lee, Jae-Joon

2016-03-01

We demonstrated the localized surface plasmon resonance (LSPR) effect of Ni nanoparticles (NiNPs) on the performance of dye-sensitized solar cells (DSSCs). Our study revealed that NiNPs in a conventional I-/I3- electrolyte (NiNPs@I-/I3-) increased the net optical absorption of a N719 dye over a broad wavelength range by LSPR, and concurrently improved the power conversion efficiency (PCE) in DSSCs. At an optimized concentration of the NiNPs@I-/I3- electrolyte (1 mg mL-1), N719-sensitized DSSCs with a photoanode thickness of ca. 2, 5, and 10 μm, exhibited net PCEs of 2.32, 6.02, and 9.83%, respectively. These efficiencies were consistent with a net improvement of 43.2, 20.4, and 12.7%, respectively and were mainly attributed to a significant enhancement of the short circuit current density (Jsc) by the LSPR from the NiNPs. Similar effects were observed for cells sensitized by the N3, Ru505, and Z907 dyes. Furthermore, the NiNPs exhibited excellent resistance to corrosion from a conventional I-/I3- electrolyte over a period of 60 days.We demonstrated the localized surface plasmon resonance (LSPR) effect of Ni nanoparticles (NiNPs) on the performance of dye-sensitized solar cells (DSSCs). Our study revealed that NiNPs in a conventional I-/I3- electrolyte (NiNPs@I-/I3-) increased the net optical absorption of a N719 dye over a broad wavelength range by LSPR, and concurrently improved the power conversion efficiency (PCE) in DSSCs. At an optimized concentration of the NiNPs@I-/I3- electrolyte (1 mg mL-1), N719-sensitized DSSCs with a photoanode thickness of ca. 2, 5, and 10 μm, exhibited net PCEs of 2.32, 6.02, and 9.83%, respectively. These efficiencies were consistent with a net improvement of 43.2, 20.4, and 12.7%, respectively and were mainly attributed to a significant enhancement of the short circuit current density (Jsc) by the LSPR from the NiNPs. Similar effects were observed for cells sensitized by the N3, Ru505, and Z907 dyes. Furthermore, the NiNPs exhibited excellent resistance to corrosion from a conventional I-/I3- electrolyte over a period of 60 days. Electronic supplementary information (ESI) available: Details of the materials, optimization of the amount of NiNPs, and the stability of the devices. See DOI: 10.1039/c5nr08155f

Characterization of N3 dye adsorption on TiO2 using quartz-crystal microbalance with dissipation monitoring

NASA Astrophysics Data System (ADS)

Wayment-Steele, Hannah K.; Johnson, Lewis E.; Dixon, Matthew C.; Johal, Malkiat S.

2013-09-01

Understanding the kinetics of dye adsorption on semiconductors is crucial for designing dye-sensitized solar cells (DSSCs) with enhanced efficiency. Harms et al. recently applied the Quartz-Crystal Microbalance with Dissipation Monitoring (QCM-D) to study in situ dye adsorption on flat TiO2 surfaces. QCM-D measures adsorption in real time and therefore allows one to determine the kinetics of the process. In this work, we characterize the adsorption of N3, a commercial RuBipy dye, using the native oxide layer of a titanium sensor to simulate the TiO2 substrate of a DSSC. We report equilibrium constants that are in agreement with previous absorbance studies of N3 adsorption, and therefore demonstrate the native oxide layer of a titanium sensor as a valid and readily available planar TiO2 morphology to study dye adsorption.

Direct identification of early synthetic dyes: FT-Raman study of the illustrated broadside prints of José Gaudalupe Posada (1852-1913)

NASA Astrophysics Data System (ADS)

Casadio, F.; Mauck, K.; Chefitz, M.; Freeman, R.

2010-09-01

Fourier Transform (FT)-Raman spectroscopy was used for the non-invasive, direct identification of colorants used to dye historical printed papers, overcoming obstacles such as low concentration of the dye, faded colors and fluorescence interference of the aged paper substrate. Based on a newly created FT-Raman reference database of 20 widely used dyes in the 19th century paper industry, the detectability of these dyes on aged biomaterials was determined by studying dyed paper samples from contemporary dye manuals, and identifying diagnostic peaks detectable on those substrates. Lastly, the method was applied to analyze the colorants used to dye the papers of a group of prints illustrated by the influential Mexico City artist José Guadalupe Posada, active 1876-1913. Unambiguous identification of the synthetic organic colorants Malachite Green (a triarylmethane dye), Orange II and Metanil Yellow (two acid monoazo dyes), Cotton Scarlet (an acid diazo dye), Phloxine (a xanthene dye) and Victoria Blue (a triarylmethane dye) in several of Posada’s prints challenged previous art-historical assumptions that these artworks were colored with natural dyes. The acquired knowledge has important conservation implications given that aniline dyes are sensitive to light and to aqueous treatments otherwise commonly carried out on works of art on paper.

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

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

Wu, Xiang; Zhang, Yuanwei; Takle, Kendra

2016-01-26

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

Solvothermal Synthesis of Hierarchical TiO2 Microstructures with High Crystallinity and Superior Light Scattering for High-Performance Dye-Sensitized Solar Cells.

PubMed

Li, Zhao-Qian; Mo, Li-E; Chen, Wang-Chao; Shi, Xiao-Qiang; Wang, Ning; Hu, Lin-Hua; Hayat, Tasawar; Alsaedi, Ahmed; Dai, Song-Yuan

2017-09-20

In this article, hierarchical TiO 2 microstructures (HM-TiO 2 ) were synthesized by a simple solvothermal method adopting tetra-n-butyl titanate as the titanium source in a mixed solvent composed of N,N-dimethylformamide and acetic acid. Due to the high crystallinity and superior light-scattering ability, the resultant HM-TiO 2 are advantageous as photoanodes for dye-sensitized solar cells. When assembled to the entire photovoltaic device with C101 dye as a sensitizer, the pure HM-TiO 2 -based solar cells showed an ultrahigh photovoltage up to 0.853 V. Finally, by employing the as-obtained HM-TiO 2 as the scattering layer and optimizing the architecture of dye-sensitized solar cells, both higher photovoltage and incident photon-to-electron conversion efficiency value were harvested with respect to TiO 2 nanoparticles-based dye-sensitized solar cells, resulting in a high power conversion efficiency of 9.79%. This work provides a promising strategy to develop photoanode materials with outstanding photoelectric conversion performance.

Effect of wavelength and dye selection on biosensor response

NASA Astrophysics Data System (ADS)

Ligler, Frances S.; Breslin, Kristen A.; Cao, Lynn K.; Anderson, George P.

1995-05-01

The availability of low cost laser diodes and new fluorescent dyes has made portable biosensors a reality. Previously, we have examined the variation in the fluorescent signal generated in an antigen-antibody reaction when the antigen is labeled with dyes exciting at different wavelengths. In this study, we looked at the effect of changing dyes and wavelengths on a sandwich immunoassay for the F1 antigen from Yersinia pestis, the etiologic agent of plaque. The F1 immunoassay has previously been demonstrated to work in serum, plasma, and even whole blood, when performed using a fiber optic biosensor. In this study, we demonstrated that changing to cyanine dyes enhanced the sensitivity of the detection without altering the immunochemistry of the assay.

Triphenylamine based organic dyes for dye sensitized solar cells: A theoretical approach

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

Mohankumar, V.; Pandian, Muthu Senthil; Ramasamy, P., E-mail: ramasamyp@ssn.edu.in

2016-05-23

The geometry, electronic structure and absorption spectra for newly designed triphenylamine based organic dyes were investigated by density functional theory (DFT) and time dependent density functional theory (TD-DFT) with the Becke 3-Parameter-Lee-Yang-parr(B3LYP) functional, where the 6-31G(d,p) basis set was employed. All calculations were performed using the Gaussian 09 software package. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule. Ultraviolet–visible (UV–vis) spectrum was simulated by TD-DFT in gas phase. The calculation shows that all of the dyes can potentially be good sensitizers for DSSC. The LUMOs are just above the conduction band of TiO{sub 2}more » and their HOMOs are under the reduction potential energy of the electrolytes (I{sup −}/I{sub 3}{sup −}) which can facilitate electron transfer from the excited dye to TiO{sub 2} and charge regeneration process after photo oxidation respectively. The simulated absorption spectrum of dyes match with solar spectrum. Frontier molecular orbital results show that among all the three dyes, the “dye 3” can be used as potential sensitizer for DSSC.« less

Self-Assembled ZnO Nanosheet-Based Spherical Structure as Photoanode in Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Ameri, Mohsen; Raoufi, Meysam; Zamani-Meymian, M.-R.; Samavat, Feridoun; Fathollahi, M.-R.; Mohajerani, Ezeddin

2018-03-01

High surface area and enhanced light scattering of ZnO nanosheet aggregates have made them a promising active layer candidate material for fabrication of nanostructure dye-sensitized solar cells. Here, we propose a facile preparation method of such ZnO nanosheet structures, and in order to verify their applicability as photoanode material for dye-sensitized solar cells, we employ morphological, optical, structural and electrical measurements. The results reveal the high surface area available for dye molecules for enhancing adsorption, high light scattering and competitive power conversion efficiencies compared to the works in literature. Finally, the device is optimized with respect to the photoanode thickness. The favorable features shown here can extend the application of the structure to other types of sensitization-based perovskite and quantum dot solar cells.

Preparation of Nanoporous TiO2 for Dye-Sensitized Solar Cell (DSSC) Using Various Dyes

NASA Astrophysics Data System (ADS)

Yuliarto, Brian; Fanani, Fahiem; Fuadi, M. Kasyful; Nugraha

2010-10-01

This article reports the development of organic dyes as an attempt to reduce material costs of Dye-Sensitized Solar Cell (DSSC). Indonesia, a country with variety and considerable number of botanical resources, is suitable to perform the research. Indonesian black rice, curcuma, papaya leaf, and the combination were chosen as organic dyes source. Dyes were extracted using organic solvent and adsorbed on mesoporous Titanium Dioxide (TiO2) which has been optimized in our laboratory. The best dyes light absorbance and performance obtained from papaya leaf as chlorophyll dyes that gives two peaks at 432 nm and 664 nm from UV-Vis Spectrophotometry and performance under 100 mW/cm2 Xenon light solar simulator gives VOC = 0.566 Volt, JSC = 0.24 mA/cm2, Fill Factor = 0.33, and efficiency of energy conversion 0,045%.

Optoelectronic and Photovoltaic Performances of Pyridine Based Monomer and Polymer Capped ZnO Dye-Sensitized Solar Cells.

PubMed

Singh, Satbir; Raj, Tilak; Singh, Amarpal; Kaur, Navneet

2016-06-01

The present research work describes the comparative analysis and performance characteristics of 4-pyridine based monomer and polymer capped ZnO dye-sensitized solar cells. The N, N-dimethyl-N4-((pyridine-4yl)methylene) propaneamine (4,monomer) and polyamine-4-pyridyl Schiff base (5, polymer) dyes were synthesized through one step condensation reaction between 4-pyridinecarboxaldehyde 1 and N, N-dimethylpropylamine 2/polyamine 3. Products obtained N, N-dimethyl-N4-((pyridine-4yl)methylene)propaneamine (4) and polyamine-4-pyridyl Schiff base (5) were purified and characterized using 1H, 13C NMR, mass, IR and CHN spectroscopy. Both the dyes 4 and 5 were further coated over ZnO nanoparticles and characterized using SEM, DLS and XRD analysis. Absorption profile and emission profile was monitored using fluorescence and UV-Vis absorption spectroscopy. A thick layer of these inbuilt dye linked ZnO nanoparticles of dyes (4) and (5) was pasted on one of the conductive side of ITO glass followed with a liquid electrolyte and counter electrode of the same conductive glass. Polyamine-4-pyridyl Schiff base polymer (5) decorated dye sensitized solar cell has shown better exciting photovoltaic properties in the form of short circuit current density (J(sc) = 6.3 mA/cm2), open circuit photo voltage (V(oc) = 0.7 V), fill factor (FF = 0.736) than monomer decorated dye sensitized solar cell. Polymer dye (5) based ZnO solar cell has shown a maximum solar power to electrical conversion efficiency of 3.25%, which is enhanced by 2.16% in case of monomer dye based ZnO solar cell under AM 1.5 sun illuminations.

Ionic Liquid Electrolytes for Flexible Dye-Sensitized Solar Cells

DTIC Science & Technology

2014-09-01

High-Efficiency Solar - Cell Based on Dye-Sensitized Colloidal TiO2 Films,” a DSSC consists of four main components: a photoanode, a counter... solar cell modules. 2. Experiment and Calculations 2.1 Materials Commercial TiO2 paste was purchased from Dyesol, and additional nanophase TiO2 ...B.; Grätzel, M. A Low-Cost, High Efficiency Solar Cell Based on Dye_Sensitized Colloidal TiO2 Films. Nature 1991, 353, 737–740. 2. Snaith, H. J

Novel energy relay dyes for high efficiency dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Rahman, Md. Mahbubur; Ko, Min Jae; Lee, Jae-Joon

2015-02-01

4',6-Diamidino-2-phenylindole (DAPI) and Hoechst 33342 (H33342) were used as novel energy relay dyes (ERDs) for an efficient energy transfer to the N719 dye in I-/I3- based liquid-junction dye-sensitized solar cells (DSSCs). The introduction of the ERDs, either as an additive in the electrolyte or as a co-adsorbent, greatly enhanced the power conversion efficiencies (PCEs), mainly because of an increase in short-circuit current density (Jsc). This was attributed to the effects of non-radiative Förster-type excitation energy transfer as well as the radiative (emission)-type fluorescent energy transfer to the sensitizers. The net PCEs for the N719-sensitized DSSCs with DAPI and H33342 were 10.65% and 10.57%, and showed an improvement of 12.2% and 11.4% over control devices, respectively.4',6-Diamidino-2-phenylindole (DAPI) and Hoechst 33342 (H33342) were used as novel energy relay dyes (ERDs) for an efficient energy transfer to the N719 dye in I-/I3- based liquid-junction dye-sensitized solar cells (DSSCs). The introduction of the ERDs, either as an additive in the electrolyte or as a co-adsorbent, greatly enhanced the power conversion efficiencies (PCEs), mainly because of an increase in short-circuit current density (Jsc). This was attributed to the effects of non-radiative Förster-type excitation energy transfer as well as the radiative (emission)-type fluorescent energy transfer to the sensitizers. The net PCEs for the N719-sensitized DSSCs with DAPI and H33342 were 10.65% and 10.57%, and showed an improvement of 12.2% and 11.4% over control devices, respectively. Electronic supplementary information (ESI) available: Details of the materials and instrumentation, device fabrication, measurement and calculations of the quantum yield (Qd), calculations of the Förster radius (R0), optimization of the ERDs mixed with electrolyte according to Type-A strategy; normalized absorption profiles of the N3, Ru505, and Z907 dyes and the emission profiles of DAPI and H33342; J-V characteristics of ERD-incorporated DSSCs sensitized with N3, Ru505, and Z907 (Type-A strategy). See DOI: 10.1039/c4nr06645f

Comparison of chitosan and chitosan nanoparticles on the performance and charge recombination of water-based gel electrolyte in dye sensitized solar cells.

PubMed

Khalili, Malihe; Abedi, Mohammad; Amoli, Hossein Salar; Mozaffari, Seyed Ahmad

2017-11-01

In commercialization of liquid dye-sensitized solar cells (DSSCs), whose leakage, evaporation and toxicity of organic solvents are limiting factors, replacement of organic solvents with water-based gel electrolyte is recommended. This work reports on utilizing and comparison of chitosan and chitosan nanoparticle as different gelling agents in preparation of water-based gel electrolyte in fabrication of dye sensitized solar cells. All photovoltaic parameters such as open circuit voltage (V oc ), fill factor (FF), short circuit current density (J sc ) and conversion efficiency (η) were measured. For further characterization, electrochemical impedance spectroscopy (EIS) was used to study the charge transfer at Pt/electrolyte interface and charge recombination and electron transport at TiO 2 /dye/electrolyte interface. Significant improvements in conversion efficiency and short circuit current density of DSSCs fabricated by chitosan nanoparticle were observed that can be attributed to the higher mobility of I 3 - due to the lower viscosity and smaller size of chitosan nanoparticles. Copyright © 2017 Elsevier Ltd. All rights reserved.

A viscosity sensitive fluorescent dye for real-time monitoring of mitochondria transport in neurons.

PubMed

Baek, Yeonju; Park, Sang Jun; Zhou, Xin; Kim, Gyungmi; Kim, Hwan Myung; Yoon, Juyoung

2016-12-15

We present here a viscosity sensitive fluorescent dye, namely thiophene dihemicyanine (TDHC), that enables the specific staining of mitochondria. In comparison to the common mitochondria tracker (Mitotracker Deep Red, MTDR), this dye demonstrated its unique ability for robust staining of mitochondria with high photostability and ultrahigh signal-to-noise ratio (SNR). Moreover, TDHC also showed high sensitivity towards mitochondria membrane potential (ΔΨm) and intramitochondria viscosity change. Consequently, this dye was utilized in real-time monitoring of mitochondria transport in primary cortical neurons. Finally, the Two-Photon Microscopy (TPM) imaging ability of TDHC was also demonstrated. Copyright © 2016 Elsevier B.V. All rights reserved.

Plasma dye coating as straightforward and widely applicable procedure for dye immobilization on polymeric materials.

PubMed

De Smet, Lieselot; Vancoillie, Gertjan; Minshall, Peter; Lava, Kathleen; Steyaert, Iline; Schoolaert, Ella; Van De Walle, Elke; Dubruel, Peter; De Clerck, Karen; Hoogenboom, Richard

2018-03-16

Here, we introduce a novel concept for the fabrication of colored materials with significantly reduced dye leaching through covalent immobilization of the desired dye using plasma-generated surface radicals. This plasma dye coating (PDC) procedure immobilizes a pre-adsorbed layer of a dye functionalized with a radical sensitive group on the surface through radical addition caused by a short plasma treatment. The non-specific nature of the plasma-generated surface radicals allows for a wide variety of dyes including azobenzenes and sulfonphthaleins, functionalized with radical sensitive groups to avoid significant dye degradation, to be combined with various materials including PP, PE, PA6, cellulose, and PTFE. The wide applicability, low consumption of dye, relatively short procedure time, and the possibility of continuous PDC using an atmospheric plasma reactor make this procedure economically interesting for various applications ranging from simple coloring of a material to the fabrication of chromic sensor fabrics as demonstrated by preparing a range of halochromic materials.

A combined spectroscopic and TDDFT study of natural dyes extracted from fruit peels of Citrus reticulata and Musa acuminata for dye-sensitized solar cells.

PubMed

Prima, Eka Cahya; Hidayat, Novianto Nur; Yuliarto, Brian; Suyatman; Dipojono, Hermawan Kresno

2017-01-15

This study reports the novel spectroscopic investigations and enhanced the electron transfers of Citrus reticulata and Musa acuminata fruit peels as the photosensitizers for the dye-sensitized solar cells. The calculated TD-DFT-UB3LYP/6-31+G(d,p)-IEFPCM(UAKS), experiment spectra of ultra-violet-visible spectroscopy, and Fourier transform infrared spectroscopy studies indicate the main flavonoid (hesperidin and gallocatechin) structures of the dye extracts. The optimized flavonoid structures are calculated using Density functional theory (DFT) at 6-31+G(d,p) level. The rutinosyl group of the hesperidin pigment (Citrus reticulata) will be further investigated compared to the gallocatechin (Musa acuminata) pigment. The acidity of the dye extract is treated by adding 2% acetic acid. The energy levels of the HOMO-LUMO dyes are measured by a combined Tauc plot and cyclic voltammetry contrasted with the DFT data. The electrochemical impedance spectroscopy will be performed to model the dye electron transfer. As for the rutinosyl group presence and the acidic treatment, the acidified Citrus reticulata cell under continuous light exposure of 100mW·cm -2 yields a short-circuit current density (J sc ) of 3.23mA/cm 2 , a photovoltage (V oc ) of 0.48V, and a fill factor of 0.45 corresponding to an energy conversion efficiency (η) of 0.71% because the shifting down HOMO-LUMO edges and the broadening dye's absorbance evaluated by a combined spectroscopic and TD-DFT method. The result also leads to the longest diffusion length of 32.2μm, the fastest electron transit of 0.22ms, and the longest electron lifetime of 4.29ms. Copyright © 2016 Elsevier B.V. All rights reserved.

A combined spectroscopic and TDDFT study of natural dyes extracted from fruit peels of Citrus reticulata and Musa acuminata for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Prima, Eka Cahya; Hidayat, Novianto Nur; Yuliarto, Brian; Suyatman; Dipojono, Hermawan Kresno

2017-01-01

This study reports the novel spectroscopic investigations and enhanced the electron transfers of Citrus reticulata and Musa acuminata fruit peels as the photosensitizers for the dye-sensitized solar cells. The calculated TD-DFT-UB3LYP/6-31 + G(d,p)-IEFPCM(UAKS), experiment spectra of ultra-violet-visible spectroscopy, and Fourier transform infrared spectroscopy studies indicate the main flavonoid (hesperidin and gallocatechin) structures of the dye extracts. The optimized flavonoid structures are calculated using Density functional theory (DFT) at 6-31 + G(d,p) level. The rutinosyl group of the hesperidin pigment (Citrus reticulata) will be further investigated compared to the gallocatechin (Musa acuminata) pigment. The acidity of the dye extract is treated by adding 2% acetic acid. The energy levels of the HOMO-LUMO dyes are measured by a combined Tauc plot and cyclic voltammetry contrasted with the DFT data. The electrochemical impedance spectroscopy will be performed to model the dye electron transfer. As for the rutinosyl group presence and the acidic treatment, the acidified Citrus reticulata cell under continuous light exposure of 100 mW·cm- 2 yields a short-circuit current density (Jsc) of 3.23 mA/cm2, a photovoltage (Voc) of 0.48 V, and a fill factor of 0.45 corresponding to an energy conversion efficiency (η) of 0.71% because the shifting down HOMO-LUMO edges and the broadening dye's absorbance evaluated by a combined spectroscopic and TD-DFT method. The result also leads to the longest diffusion length of 32.2 μm, the fastest electron transit of 0.22 ms, and the longest electron lifetime of 4.29 ms.

Combined use of two membrane-potential-sensitive dyes for determination of the Galvani potential difference across a biomimetic oil/water interface.

PubMed

Yoshimura, Tatsuya; Nagatani, Hirohisa; Osakai, Toshiyuki

2014-05-01

The fluorescence behavior of anionic membrane-potential-sensitive dyes, bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC4(3)) and bis-(1,3-diethylthiobarbituric acid)trimethine oxonol (DiSBAC2(3)), at a biomimetic 1,2-dichloroethane (DCE)/water (W) interface was studied by the mean of potential-modulated fluorescence (PMF) spectroscopy. The respective dyes gave a well-defined PMF signal due to the adsorption/desorption at the DCE/W interface. It was also found that the potentials where the two dyes gave the PMF signals were different by about 100 mV. We then attempted a combined use of the two dyes for determination of the Galvani potential difference across the DCE/W interface. When 40 μM DiBAC4(3) and 15 μM DiSBAC2(3) were initially added to the W phase, distinctly different spectra were obtained for different interfacial potentials. The ratio of the PMF signal intensities at 530 and 575 nm (the fluorescence maximum wavelengths for the respective dyes) showed a clear dependence on the interfacial potential. These results suggested the potential utility of the combined use of two dyes for the determination of membrane potentials in vivo.

Optical properties of voltage sensitive hemicyanine dyes of variable hydrophobicity confined within surfactant micelles

NASA Astrophysics Data System (ADS)

Naeem, Kashif; Naseem, Bushra; Shah, S. S.; Shah, Syed W. H.

2017-11-01

The optical properties of amphiphilic hemicyanine dyes with variable hydrophobicity, confined within anionic micelles of sodium dodecylbenzenesulfonate (NaDDBS) have been studied by UV-visible absorption spectroscopy. The confinement constant, K conf has been determined for each entrapped dye. The ion-pair formation between dye and surfactant causes a decline in electronic transition energy (ΔE T) when dye alkyl chains are smaller due to stabilization of both the ground and excited state. ΔE T values gradually increase with increase in dye hydrophobicity that hampers the electrostatic interaction with dialkylammonium moiety and consequently excited state stabilization is compromised. The average number of dye molecules trapped in a single micelle was also determined. The negative values of Gibbs free energy indicate that the dye entrapment within micelles is energetically favored. These findings have significance for developing functional materials with peculiar luminescent properties, especially for more effective probing of complex biological systems.

Newer approach of using alternatives to (Indium doped) metal electrodes, dyes and electrolytes in dye sensitized solar cell

NASA Astrophysics Data System (ADS)

Patni, Neha; Sharma, Pranjal; Pillai, Shibu G.

2018-04-01

This work demonstrates the PV study of dye sensitised solar cells by fabricating the (PV) cell using the ITO, FTO and AZO glass substrate. Dyes used for the fabrication were extracted from beetroot and spinach and a cocktail dye by mixing both of the dyes was also prepared. Similarly the three dufferent electrolytes used were iodide-triiodide couple, polyaniline and mixture of polyaniline and iodide couple. Mixed dye and mixed electrolyte has emerged as the highest efficient cell. The electrical characterisation shows that the highest power conversion efficiency of 1.86% was achieved by FTO substrate, followed by efficiency of 1.83% by AZO substrate and efficiency of 1.63% with ITO substrate using mixed dye and mixed electrolyte approach. This justifies that FTO and AZO shows better efficiency and hence proposed to be used as an alternative to indium free system.

pH-sensitive Itaconic acid based polymeric hydrogels for dye removal applications.

PubMed

Sakthivel, M; Franklin, D S; Guhanathan, S

2016-12-01

A series of Itaconic Acid (IA) based pH-sensitive polymeric hydrogels were synthesized by condensation polymerization of Itaconic Acid (IA) with Ethylene Glycol (EG) in the presence of an acid medium resulted into pre-polymer. Further, pre-polymer were co-polymerized with Acrylic Acid (AA) through free radical polymerization using Potassium persulphate (KPS). The structural and surface morphological characterizations of the synthesized hydrogels were studied using FT-IR spectroscopy and Scanning Electron Microscope (SEM) respectively. The swelling and swelling equilibrium were performed at varies pH (4.0-10.0). Further, the effects of IA, EG and AA on swelling properties have also been investigated. Thermal stability of synthesized hydrogels have been investigated by TGA, DTA and DSC. The synthesized hydrogels have shown good ability to uptake a Cationic dye. The Methylene blue has been chosen as a model cationic dye. The results of dye removal using IA hydrogels found to have excellent dye removal capacity. Such kind of IA based hydrogels may be recommended for eco-friendly environmental application. viz., removal of dyes and metal ions and sewage water treatment, purification of water etc. Copyright © 2015 Elsevier Inc. All rights reserved.

A Novel of Buton Asphalt and Methylene Blue as Dye-Sensitized Solar Cell using TiO2/Ti Nanotubes Electrode

NASA Astrophysics Data System (ADS)

Nurhidayani; Muzakkar, M. Z.; Maulidiyah; Wibowo, D.; Nurdin, M.

2017-11-01

A study of TiO2/Ti nanotubes arrays (NTAs) based on Dye-Sensitized Solar Cell (DSSC) used Asphalt Buton (Asbuton) extract and methylene blue (MB) as a photosensitizer dye has been conducted. The aim of this research is that the Asbuton extract and Methylene Blue (MB) performance as a dye on DSSC solar cells is able to obtain the voltage-currents produced by visible light irradiation. Electrode TiO2/Ti NTAs have been successfully synthesized by anodizing methods, then characterized by using XRD showed that the anatase crystals formed. Subsequently, the morphology showed that the nanotubes formed which has coated by Asbuton extract. The DSSC system was formed by a sandwich structure and tested by using Multimeter Digital with Potentiostat instrument. The characteristics of current (I) and potential (V) versus time indicated that the Asbuton was obtained in a high-performance in 30s of 14,000µV 0.844µA, meanwhile MB dyes were 8,000µV0.573µA. Based on this research, the Asbuton extract from Buton Island-Southeast Sulawesi-Indonesia was potential for natural dyes in DSSC system.

Theoretical study of electronic transfer current rate at dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

AL-Agealy, Hadi J. M.; AlMaadhede, Taif Saad; Hassooni, Mohsin A.; Sadoon, Abbas K.; Ashweik, Ahmed M.; Mahdi, Hind Abdlmajeed; Ghadhban, Rawnaq Qays

2018-05-01

In this research, we present a theoretical study of electronic transfer kinetics rate in N719/TiO2 and N719/ZnO dye-sensitized solar cells (DSSC) systems using a simple model depending on the postulate of quantum mechanics theory. The evaluation of the electronic transition current rate in DSSC systems are function of many parameters such that; the reorientation transition energies ΛSe m D y e , the transition coupling parameter ℂT(0), potential exponential effect e-(E/C-EF ) kBT , unit cell volume VSem, and temperature T. Furthermore, the analysis of electronic transfer current rate in N719/TiO2 and N719/ZnO systems show that the rate upon dye-sensitization solar cell increases with increases of transition coupling parameter, decreasing potential that building at interface a results of different material in this devices and increasing with reorientation transition energy. On the other hand, we can find the electronic transfer behavior is dependent of the dye absorption spectrum and mainly depending on the reorientation of transition energy. The replacement of the solvents in both DSSC system caused increasing of current rates dramatically depending on polarity of solvent in subset devices. This change in current rate of electron transfer were attributed to much more available of recombination sites introduced by the solvents medium. The electronic transfer current dynamics are shown to occurs in N719/TiO2 system faster many time compare to ocuures at N719/ZnO system, this indicate that TiO2 a is a good and active material compare with ZnO to using in dye sensitized solar cell devices. In contrast, the large current rate in N719/TiO2 comparing to ZnO of N719/ZnO systems indicate that using TiO2 with N719 dye lead to increasing the efficiency of DSSC.

The Influence of Substituent Orientation on the Photovoltaic Performance of Phthalocyanine-Sensitized Solar Cells.

PubMed

Tejerina, Lara; Martínez-Díaz, M Victoria; Nazeeruddin, Mohammad Khaja; Torres, Tomas

2016-03-18

Phthalocyanines (Pcs) are used as sensitizers in dye-sensitized solar cells (DSSCs) because of their stability and intense absorption in the red and near-IR regions. Impressive progress has been made in photovoltaic efficiencies by introduction of bulky peripheral substituents to help suppress macrocycle aggregation. To reach benchmark efficiencies reported for other related dyes, new designs need to be explored. Single carboxy-ZnPc regioisomers substituted at the non-peripheral positions by rigid aryl groups have now been studied, which has shed light on the influence of steric hindrance and/or orientation of the substituent around the anchoring group on the photovoltaic response. The regioisomer bearing the aryl group far away from the anchoring group produces a more effective sensitization of the TiO2 films and higher short-circuit photocurrent density (Jsc). Taking advantage of the good photovoltaic performance in the near-IR region of this ZnPc, it was combined with another appropriate dye for panchromatic sensitization of the mesoporous photoelectrode and an increase of the overall device efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of auxiliary group for p-type organic dyes in NiO-based dye-sensitized solar cells: The first principal study

NASA Astrophysics Data System (ADS)

Li, Juan; Zhang, Shijie; Shao, Di; Yang, Zhenqing; Zhang, Wansong

2018-03-01

Auxiliary acceptor groups play a crucial role in D-A-π-A structured organic dyes. In this paper, we designed three D-A-π-A structured organic molecules based on the prototype dye QT-1, named ME18-ME20, and further investigated their electronic and optical properties with density functional theory (DFT) and time-dependent DFT (TDDFT). The calculated results indicate that the scope and intensity of dyes' absorption spectra have some outstanding changes by inserting auxiliary groups. ME20 has not only 152 nm redshifts to long wave orientation, but also 78% increased oscillator strength compared to QT-1, and its absorption spectrum broadens region even up to 1400 nm. Then, we studied the reason that the effect of the introduced different auxiliary acceptor groups in these dyes through their ground states geometries and energy levels, electron transfer and recombination rate.

Diolistics: incorporating fluorescent dyes into biological samples using a gene gun

PubMed Central

O’Brien, John A.; Lummis, Sarah C.R.

2007-01-01

The hand-held gene gun provides a rapid and efficient method of incorporating fluorescent dyes into cells, a technique that is becoming known as diolistics. Transporting fluorescent dyes into cells has, in the past, used predominantly injection or chemical methods. The use of the gene gun, combined with the new generation of fluorescent dyes, circumvents some of the problems of using these methods and also enables the study of cells that have proved difficult traditionally to transfect (e.g. those deep in tissues and/or terminally differentiated); in addition, the use of ion- or metabolite-sensitive dyes provides a route to study cellular mechanisms. Diolistics is also ideal for loading cells with optical nanosensors – nanometre-sized sensors linked to fluorescent probes. Here, we discuss the theoretical considerations of using diolistics, the advantages compared with other methods of inserting dyes into cells and the current uses of the technique, with particular consideration of nanosensors. PMID:17945370

Development of dye-sensitized solar cells based on naturally extracted dye from the maqui berry (Aristotelia chilensis)

NASA Astrophysics Data System (ADS)

Leyrer, Julio; Hunter, Renato; Rubilar, Monica; Pavez, Boris; Morales, Eduardo; Torres, Simonet

2016-10-01

The mini modules of dye-sensitized solar cells (DSSCs) were investigated for their conversion efficiency using anthocyanin-enriched extracts from maqui berry, which to date has never been tested in a DSSC. Anthocyanins are a group of red, purple, violet and blue water-soluble polyphenolic pigments widely found in berry fruits. Maqui berries are a particularly rich source. The aqueous extract concentrations of maqui fruit were tested at 750 and 1500 mg of anthocyanin/L. The immersion time to produce sensitized TiO2 film was 8 h. According to the experimental results, the conversion efficiency of the DSSC prepared with 750 mg of anthocyanin/L was 0.14%, with an open-circuit voltage (VOC) of 0.43 V, a short-circuit current density (JSC) of 0.38 mA/cm2, and a fill factor (FF) of 0.450. The conversion efficiency attained with 1500 mg of anthocyanin/L was 0.19%, with (VOC) of 0.45 V, (JSC) of 0.44 mA/cm2 and FF of 0.55. Therefore, a higher concentration brought about a higher photosensitized performance. The maqui extracts were successfully dye sensitized over a layer of TiO2 nanoparticles, providing useful information for further studies related to the use of natural pigments as sensitizers for solar cells.

Characterization of multi-dye pressure-sensitive microbeads

NASA Astrophysics Data System (ADS)

Lacroix, Daniel; Viraye-Chevalier, Teddy; Seiter, Guillaume; Howard, Jonathan; Dabiri, Dana; Khalil, Gamal E.; Xia, Younan; Zhu, Cun

2013-11-01

The response times of pressure-sensitive particles to passing shockwaves were measured to investigate their ability to accurately determine pressure changes in unsteady flows. The particles tested were loaded with novel pressure-sensitive dyes such as Pt (II) meso-tetra(pentafluorophenyl)porphine, Pt(II) octaethylporphine, bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl))iridium III, and iridium(III) bis(4-phenylthieno[3,2-c] pyridinato-N,C2')acetylacetonate. For this work, porous silicon dioxide pressure-sensitive beads (PSBeads) were used. Two synthetic procedures were used to fabricate the particles. In the first, a one-step method loaded dyes during the synthesis of microbeads, in the second a two-step method synthesized the microbeads first, then loaded the dyes. The shock tube facility was used to measure the response times of microbeads to fast pressure jumps. The study involved testing multiple luminophors loaded in microbeads with various size distributions. Response times for the silica-based microbeads ranged between 26 μs and 462 μs (at 90% of the amplitude response), which are much faster than previously reported polystyrene-based microbead response times, which range from 507 μs to 1582 μs (at 90% of the amplitude response) [F. Kimura, M. Rodriguez, J. McCann, B. Carlson, D. Dabiri, G. Khalil, J. B. Callis, Y. Xia, and M. Gouterman, "Development and characterization of fast responding pressure sensitive microspheres," Rev. Sci. Instrum. 79, 074102 (2008)].

Performance Characterization of Dye-Sensitized Photovoltaics under Indoor Lighting.

PubMed

Chen, Chia-Yuan; Jian, Zih-Hong; Huang, Shih-Han; Lee, Kun-Mu; Kao, Ming-Hsuan; Shen, Chang-Hong; Shieh, Jia-Min; Wang, Chin-Li; Chang, Chiung-Wen; Lin, Bo-Zhi; Lin, Ching-Yao; Chang, Ting-Kuang; Chi, Yun; Chi, Cheng-Yu; Wang, Wei-Ting; Tai, Yian; Lu, Ming-De; Tung, Yung-Liang; Chou, Po-Ting; Wu, Wen-Ti; Chow, Tahsin J; Chen, Peter; Luo, Xiang-Hao; Lee, Yuh-Lang; Wu, Chih-Chung; Chen, Chih-Ming; Yeh, Chen-Yu; Fan, Miao-Syuan; Peng, Jia-De; Ho, Kuo-Chuan; Liu, Yu-Nan; Lee, Hsiao-Yi; Chen, Chien-Yu; Lin, Hao-Wu; Yen, Chia-Te; Huang, Yu-Ching; Tsao, Cheng-Si; Ting, Yu-Chien; Wei, Tzu-Chien; Wu, Chun-Guey

2017-04-20

Indoor utilization of emerging photovoltaics is promising; however, efficiency characterization under room lighting is challenging. We report the first round-robin interlaboratory study of performance measurement for dye-sensitized photovoltaics (cells and mini-modules) and one silicon solar cell under a fluorescent dim light. Among 15 research groups, the relative deviation in power conversion efficiency (PCE) of the samples reaches an unprecedented 152%. On the basis of the comprehensive results, the gap between photometry and radiometry measurements and the response of devices to the dim illumination are identified as critical obstacles to the correct PCE. Therefore, we use an illuminometer as a prime standard with a spectroradiometer to quantify the intensity of indoor lighting and adopt the reverse-biased current-voltage (I-V) characteristics as an indicator to qualify the I-V sampling time for dye-sensitized photovoltaics. The recommendations can brighten the prospects of emerging photovoltaics for indoor applications.

Stability issues pertaining large area perovskite and dye-sensitized solar cells and modules

NASA Astrophysics Data System (ADS)

Castro-Hermosa, S.; Yadav, S. K.; Vesce, L.; Guidobaldi, A.; Reale, A.; Di Carlo, A.; Brown, T. M.

2017-01-01

Perovskite and dye-sensitized solar cells are PV technologies which hold promise for PV application. Arguably, the biggest issue facing these technologies is stability. The vast majority of studies have been limited to small area laboratory cells. Moisture, oxygen, UV light, thermal and electrical stresses are leading the degradation causes. There remains a shortage of stability investigations on large area devices, in particular modules. At the module level there exist particular challenges which can be different from those at the small cell level such as encapsulation (not only of the unit cells but of interconnections and contacts), non-uniformity of the layer stacks and unit cells, reverse bias stresses, which are important to investigate for technologies that aim for industrial acceptance. Herein we present a review of stability investigations published in the literature pertaining large area perovskite and dye-sensitized solar devices fabricated both on rigid (glass) and flexible substrates.

Influence of the electron-cation interaction on electron mobility in dye-sensitized ZnO and TiO2 nanocrystals: a study using ultrafast terahertz spectroscopy.

PubMed

Nemec, H; Rochford, J; Taratula, O; Galoppini, E; Kuzel, P; Polívka, T; Yartsev, A; Sundström, V

2010-05-14

Charge transport and recombination in nanostructured semiconductors are poorly understood key processes in dye-sensitized solar cells. We have employed time-resolved spectroscopies in the terahertz and visible spectral regions supplemented with Monte Carlo simulations to obtain unique information on these processes. Our results show that charge transport in the active solar cell material can be very different from that in nonsensitized semiconductors, due to strong electrostatic interaction between injected electrons and dye cations at the surface of the semiconductor nanoparticle. For ZnO, this leads to formation of an electron-cation complex which causes fast charge recombination and dramatically decreases the electron mobility even after the dissociation of the complex. Sensitized TiO2 does not suffer from this problem due to its high permittivity efficiently screening the charges.

Charge Transfer Dynamics of Highly Efficient Cyanidin-3-O- Glucoside Sensitizer for Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Prima, E. C.; Yuliarto, B.; Suyatman; Dipojono, H. K.

2016-08-01

This paper reports the novel efficiency achievement of black rice-based natural dye- sensitized solar cells. The higher dye concentration, the longer dye extraction as well as dye immersion onto a TiO2 film, and the co-adsorption addition are key strategies for improved-cell performance compared to the highest previous achievement. The black rice dye containing 1.38 mM cyanidin-3-O-glucoside has been extracted without purification for 3 weeks at dark condition and room temperature. The anatase TiO2 photoanode was dipped into dye solution within 4 days. Its electrode was firmly sealed to be a cell and was filled by I-/I3- electrolyte using vacuum technique. As a result, the overall solar-to-energy conversion efficiency was 1.49% at AM 1.5 illumination (100 mW.cm-2). The voltametric analysis has reported the interfacial electronic band edges of TiO2-Dye-Electrolyte. Furthermore, electrochemical impedance spectroscopy has shown the kinetic of interfacial electron transfer dynamics among TiO2-dye-electrolyte. The cell has the transfer resistance (Rt) of 12.5 ω, the recombination resistance (Rr) of 266.8 ω, effective electron diffusion coefficients (Dn) of 1.4 × 10-3 cm2/s, Dye-TiO2 effective electron transfer (τd) of 26.6 μs, effective diffusion length (Ln)of 33.78 μm, chemical capacitance (Cμ) of 12.43 μF, and electron lifetime (τn) of 3.32 ms.

The chemical bonds effect of Amaranthus hybridus L. and Dracaena Angustifolia on TiO2 as photo-sensitizer for dye-sensitized solar Cells (DSSC)

NASA Astrophysics Data System (ADS)

Ahliha, A. H.; Nurosyid, F.; Supriyanto, A.

2017-08-01

Dye-Sensitized Solar Cells (DSSC) consists of a working electrode, dye, electrolyte, and a counter electrode. The paper showed the effect of chemical bonds Dracaena Angustifolia (suji leaves) and Amaranthus Hybridus L. (spinach leaves) on TiO2 for application in DSSC. Dracaena Angustifolia (suji leaves) and Amaranthus Hybridus L. (spinach leaves) were extracted using acetone solvent as a dye containing chlorophyll, the absorbance spectrum of the dye and TiO2 were characterized using Uv-visible spectrophotometer 1601 PC, the chemical bonds contained in TiO2-dye was characterized using FT-IR spectrophotometer Shimadzu Prestige 21. The efficiency of DSSC was calculated using I-V Keithley 2602A. Absorbance characterization of dye Dracaena Angustifolia showed two peaks at the wavelength of 665,5 nm and 412 nm. The absorbance peaks of dye Amaranthus Hybridus L. at the wavelength of 664 nm and 412,5 nm. FT-IR characterization of TiO2 founded the functional groups C=C-C, C=C-H, C-O, C-H, C=C, C-H aliphatic, and O-H. Dye Amaranthus Hybridus L. obtained functional groups C=C-C, C=C-H, C-O, C-H, C=C, C=O, C-H aliphatic, and O-H. Dye Dracaena Angustifolia obtained functional groups were identified as C=C-C, C=C-H, C-O, C-H, C=C, C-H aliphatic, and O-H. DSSC efficiency with Amaranthus Hybridus L. and Dracaena Angustifolia dyes of 0,063% and 0,058% respectively

Dye-Sensitized Solar Cells (DSSCs) reengineering using TiO2 with natural dye (anthocyanin)

NASA Astrophysics Data System (ADS)

Subodro, Rohmat; Kristiawan, Budi; Ramelan, Ari Handono; Wahyuningsih, Sayekti; Munawaroh, Hanik; Hanif, Qonita Awliya; Saputri, Liya Nikmatul Maula Zulfa

2017-01-01

This research on Dye-Sensitized Solar Cells (DSSCs) reengineering was carried out using TiO2 with natural dye (anthocyanin). The fabrication of active carbon layer/TiO2 DSSC solar cell was based on natural dye containing anthocyanins such as mangosteen peel, red rose flower, black glutinous rice, and purple eggplant peel. DSSC was prepared with TiO2 thin layer doped with active carbon; Natural dye was analyzed using UV-Vis and TiO2 was analyzed using X-ray diffractometer (XRD), meanwhile scanning electron microscope (SEM) was used to obtain the size of the crystal. Keithley instrument test was carried out to find out I-V characteristics indicating that the highest efficiency occurred in DSSCs solar cell with 24-hour soaking with mangosteen peel 0.00047%.

Ionic liquid electrolytes for dye-sensitized solar cells.

PubMed

Gorlov, Mikhail; Kloo, Lars

2008-05-28

The potential of room-temperature molten salts (ionic liquids) as solvents for electrolytes for dye-sensitized solar cells has been investigated during the last decade. The non-volatility, good solvent properties and high electrochemical stability of ionic liquids make them attractive solvents in contrast to volatile organic solvents. Despite this, the relatively high viscosity of ionic liquids leads to mass-transport limitations. Here we review recent developments in the application of different ionic liquids as solvents or components of liquid and quasi-solid electrolytes for dye-sensitized solar cells.

Ultrafast photodynamics of the indoline dye D149 adsorbed to porous ZnO in dye-sensitized solar cells.

PubMed

Rohwer, Egmont; Richter, Christoph; Heming, Nadine; Strauch, Kerstin; Litwinski, Christian; Nyokong, Tebello; Schlettwein, Derck; Schwoerer, Heinrich

2013-01-14

We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I(-)/I(3)(-) redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced Aqueous Solubility of Long Wavelength Voltage-Sensitive Dyes by Covalent Attachment of Polyethylene Glycol

PubMed Central

Patrick, Michael J.; Ernst, Lauren A.; Waggoner, Alan S.; Thai, Dung; Salama, Guy

2011-01-01

Long wavelength voltage-sensitive dyes (VSDs) called Pittsburgh (PGH) dyes were recently synthesized by coupling various heterocyclic groups to a styryl-thiophene intermediate forming extended, partially rigidized chromophores. Unlike most styryl VSDs, dyes with a sulfonic acid anchor directly attached to the chromophore showed no solvatochromic absorption shifts. The limited water solubility of many long wavelength VSDs requires the use of surfactants to transport the dye through aqueous media and effectively label biological membranes. Here, we tested the chemical substitution of the sulfonic acid moiety with polyethyleneglycol (PEG) chains ranging from MW 750 to 5000, to overcome the poor solubility of VSDs while retaining their properties as VSDs. The chemical synthesis of PGH dyes and their PEG derivatives are described. The PEG-derivatives were soluble in aqueous solutions (> 1 mM) and still reported membrane potential changes. In frog and mouse hearts, the voltage sensitivity (ΔF/F per action potential) and spectral properties of PEG dyes were the same as the sulfonated analogs. Thus, the solubility of VSDs can be considerably improved with small polyethyleneglycol chains and can provide an effective approach to improve staining of excitable tissues and optical recordings of membrane potential. PMID:17912389

Fabrication and characterization of dye-sensitized solar cells based on natural plants

NASA Astrophysics Data System (ADS)

Gu, Peng; Yang, Dingyu; Zhu, Xinghua; Sun, Hui; Li, Jitao

2018-02-01

In this paper, the dye-sensitized solar cells (DSSCs) were fabricated based on natural dyes extracting from carrot, mulberry, purple cabbage, potato, and grapes. The ultraviolet-visible spectra suggested purple cabbage and mulberry possess better absorption at 300-550 nm. The solar cells using purple cabbage as dye achieved a conversion efficiency of 0.162% with short-circuit photocurrent density (Jsc) of 0.621 mA/cm2, open circuit voltage (Voc) of 0.541 V and fill factor (FF) of 0.484. The Infrared spectra revealed the bond of Osbnd H, Csbnd C, Csbnd O, Csbnd H were existed in purple cabbage. Finally, the optimal extraction time of dyes is also presented.

Efficient quasisolid dye- and quantum-dot-sensitized solar cells using thiolate/disulfide redox couple and CoS counter electrode.

PubMed

Meng, Ke; Thampi, K Ravindranathan

2014-12-10

For the first time, a quasisolid thiolate/disulfide-based electrolyte was prepared using succinonitrile as a matrix. An optimized configuration of the quasisolid electrolyte contains 5-mercapto-1-methyltetrazole N-tetramethylammonium/disulfide/LiClO4/N-methylbenzimidazole in the molar ratio of 0.8:0.8:0.1:0.1. Dye-sensitized solar cells fabricated using this quasisolid electrolyte, together with N719 dye-sensitized photoelectrode and CoS counter electrode, attained power conversion efficiencies of 4.25% at 1 sun and 6.19% at 0.1 sun illumination intensities. The optimized quasisolid electrolyte, when introduced to quasisolid CdS quantum-dot-sensitized solar cells, exhibited a power conversion efficiency of 0.94%, despite the fact that CdS absorbs only a small fraction of the visible light, unlike dyes. The encouraging results show the potential for the utilization of the quasisolid thiolate/disulfide-based electrolyte in sensitized solar cells.

Detection Limits for Spectro-fluorometry: A Case Study in the Region of Finstersee, Canton Zug, Northern Switzerland

NASA Astrophysics Data System (ADS)

Otz, M. H.; Otz, H. K.; Keller, P.

2002-05-01

Synthetic fluorescent dyes, applied below the visual detection limit (< 0.1 mg/L), have been used as tracers of ground water flow paths since the beginning of the 1950s. Since 1965, we have used spectro-fluorometers with photomultipliers to measure low concentrations of fluorescent dyes in ground water in Switzerland. In collaboration with the Engineering Geology Department of the ETH, we have separated uranine at 0.1 ng/L and Na-naphtionate at 1 ng/L from background fluorescence of spring water in the Finstersee region. These values are 10-100 times lower than postulated detection limits in the literature. The use of low dye concentrations prevents a study region from being contaminated by increased background levels due to remnant dye within the aquifer, thereby leaving the region available for future dye tracing studies. Lower detection limits also can solve particular hydraulic problems where conventional methods fail and enhance the possibility for using artificial dyes in environmentally sensitive aquifer settings.

A cascaded QSAR model for efficient prediction of overall power conversion efficiency of all-organic dye-sensitized solar cells.

PubMed

Li, Hongzhi; Zhong, Ziyan; Li, Lin; Gao, Rui; Cui, Jingxia; Gao, Ting; Hu, Li Hong; Lu, Yinghua; Su, Zhong-Min; Li, Hui

2015-05-30

A cascaded model is proposed to establish the quantitative structure-activity relationship (QSAR) between the overall power conversion efficiency (PCE) and quantum chemical molecular descriptors of all-organic dye sensitizers. The cascaded model is a two-level network in which the outputs of the first level (JSC, VOC, and FF) are the inputs of the second level, and the ultimate end-point is the overall PCE of dye-sensitized solar cells (DSSCs). The model combines quantum chemical methods and machine learning methods, further including quantum chemical calculations, data division, feature selection, regression, and validation steps. To improve the efficiency of the model and reduce the redundancy and noise of the molecular descriptors, six feature selection methods (multiple linear regression, genetic algorithms, mean impact value, forward selection, backward elimination, and +n-m algorithm) are used with the support vector machine. The best established cascaded model predicts the PCE values of DSSCs with a MAE of 0.57 (%), which is about 10% of the mean value PCE (5.62%). The validation parameters according to the OECD principles are R(2) (0.75), Q(2) (0.77), and Qcv2 (0.76), which demonstrate the great goodness-of-fit, predictivity, and robustness of the model. Additionally, the applicability domain of the cascaded QSAR model is defined for further application. This study demonstrates that the established cascaded model is able to effectively predict the PCE for organic dye sensitizers with very low cost and relatively high accuracy, providing a useful tool for the design of dye sensitizers with high PCE. © 2015 Wiley Periodicals, Inc.

Molecular engineering of sensitizers for dye-sensitized solar cell applications.

PubMed

Giribabu, Lingamallu; Kanaparthi, Ravi Kumar; Velkannan, Veerapandian

2012-06-01

Dye-sensitized solar cells (DSSCs) have attracted considerable attention in recent years as they offer the possibility of low-cost conversion of photovoltaic energy. This account focuses on recent advances in molecular design and technological aspects of sensitizers based on metal complexes, metal-free organics and tetrapyrrolic compounds which include porphyrins, phthalocyanines as well as corroles. Special attention has been paid to the design principles of these dyes, and co-sensitization, an emerging technique to extend the absorption range, is also discussed as a way to improve the performance of the device. This account also focuses on recent advances of efficient ruthenium sensitizers as well as other metal complexes and their applications in DSSCs. Recent developments in the area of metal-free organic and tetrapyrrolic sensitizers are also discussed. Copyright © 2012 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

Enhanced Charge Separation Efficiency in Pyridine-Anchored Phthalocyanine-Sensitized Solar Cells by Linker Elongation.

PubMed

Ikeuchi, Takuro; Agrawal, Saurabh; Ezoe, Masayuki; Mori, Shogo; Kimura, Mutsumi

2015-11-01

A series of zinc phthalocyanine sensitizers (PcS22-24) having a pyridine anchoring group are designed and synthesized to investigate the structural dependence on performance in dye-sensitized solar cells. The pyridine-anchor zinc phthalocyanine sensitizer PcS23 shows 79 % incident-photon to current-conversion efficiency (IPCE) and 6.1 % energy conversion efficiency, which are comparable with similar phthalocyanine dyes having a carboxylic acid anchoring group. Based on DFT calculations, the high IPCE is attributed with the mixture of an excited-state molecular orbital of the sensitizer and the orbitals of TiO2 . Between pyridine and carboxylic acid anchor dyes, opposite trends are observed in the linker-length dependence of the IPCE. The red-absorbing PcS23 is applied for co-sensitization with a carboxyl-anchor organic dye D131 that has a complementary spectral response. The site-selective adsorption of PcS23 and D131 on the TiO2 surface results in a panchromatic photocurrent response for the whole visible-light region of sun light. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-efficiency dye-sensitized solar cells with ferrocene-based electrolytes.

PubMed

Daeneke, Torben; Kwon, Tae-Hyuk; Holmes, Andrew B; Duffy, Noel W; Bach, Udo; Spiccia, Leone

2011-03-01

Dye-sensitized solar cells based on iodide/triiodide (I(-)/I(3)(-)) electrolytes are viable low-cost alternatives to conventional silicon solar cells. However, as well as providing record efficiencies of up to 12.0%, the use of I(-)/I(3)(-) in such solar cells also brings about certain limitations that stem from its corrosive nature and complex two-electron redox chemistry. Alternative redox mediators have been investigated, but these generally fall well short of matching the performance of conventional I(-)/I(3)(-) electrolytes. Here, we report energy conversion efficiencies of 7.5% (simulated sunlight, AM1.5, 1,000 W m(-2)) for dye-sensitized solar cells combining the archetypal ferrocene/ferrocenium (Fc/Fc(+)) single-electron redox couple with a novel metal-free organic donor-acceptor sensitizer (Carbz-PAHTDTT). These Fc/Fc(+)-based devices exceed the efficiency achieved for devices prepared using I(-)/I(3)(-) electrolytes under comparable conditions, revealing the great potential of ferrocene-based electrolytes in future dye-sensitized solar cells applications. This improvement results from a more favourable matching of the redox potential of the ferrocene couple with that of the new donor-acceptor sensitizer.

Efficiencies of Dye-Sensitized Solar Cells using Ferritin-Encapsulated Quantum Dots with Various Staining Methods

NASA Astrophysics Data System (ADS)

Perez, Luis

Dye-sensitized solar cells (DSSC) have the potential to replace traditional and cost-inefficient crystalline silicon or ruthenium solar cells. This can only be accomplished by optimizing DSSC's energy efficiency. One of the major components in a dye-sensitized solar cell is the porous layer of titanium dioxide. This layer is coated with a molecular dye that absorbs sunlight. The research conducted for this paper focuses on the different methods used to dye the porous TiO2 layer with ferritin-encapsulated quantum dots. Multiple anodes were dyed using a method known as SILAR which involves deposition through alternate immersion in two different solutions. The efficiencies of DSSCs with ferritin-encapsulated lead sulfide dye deposited using SILAR were subsequently compared against the efficiencies produced by cells using the traditional immersion method. It was concluded that both methods resulted in similar efficiencies (? .074%) however, the SILAR method dyed the TiO2 coating significantly faster than the immersion method. On a related note, our experiments concluded that conducting 2 SILAR cycles yields the highest possible efficiency for this particular binding method. National Science Foundation.

Improved electron density through hetero-junction binary sensitized TiO2/ CdTe / D719 system as photoanode for dye sensitized solar cell

NASA Astrophysics Data System (ADS)

Pandey, A. K.; Ahmad, Muhammad Shakeel; Alizadeh, Mahdi; Rahim, Nasrudin Abd

2018-07-01

The combined effect of dual sensitization and hetero-junction symmetry has been investigated on the performance of TiO2 based dye sensitized solar cell. CdTe nanoparticles have been introduced in TiO2 matrix to function as sensitizer as well as act as hetero-junction between D719 dye and TiO2 nanoarchitecture. Four concentrations of CdTe i.e. 0.5 wt%, 2 wt%, 5 wt% and 8 wt% have been investigated. Morphological and compositional studies have been conducted using scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. Light absorption characteristics have been investigated by employing Uv-vis spectroscopy and the overall performance has been studied using solar simulator and electrochemical impedance spectroscopy (EIS). Performance has been found to be increased with the addition of CdTe due to high electron density and reduction in recombination reactions. An increase of 41.73% in incident photo conversion efficiency (IPCE) and 75.57% in short circuit current density (Jsc) have been recorded for the specimens containing 5 wt% CdTe compared to bare TiO2 based DSSCs. Further addition of CdTe leads to reduction in overall performance of DSSCs.

Self-assembled near-infrared dye nanoparticles as a selective protein sensor by activation of a dormant fluorophore.

PubMed

Anees, Palapuravan; Sreejith, Sivaramapanicker; Ajayaghosh, Ayyappanpillai

2014-09-24

Design of selective sensors for a specific analyte in blood serum, which contains a large number of proteins, small molecules, and ions, is important in clinical diagnostics. While metal and polymeric nanoparticle conjugates have been used as sensors, small molecular assemblies have rarely been exploited for the selective sensing of a protein in blood serum. Herein we demonstrate how a nonspecific small molecular fluorescent dye can be empowered to form a selective protein sensor as illustrated with a thiol-sensitive near-IR squaraine (Sq) dye (λabs= 670 nm, λem= 700 nm). The dye self-assembles to form nonfluorescent nanoparticles (Dh = 200 nm) which selectively respond to human serum albumin (HSA) in the presence of other thiol-containing molecules and proteins by triggering a green fluorescence. This selective response of the dye nanoparticles allowed detection and quantification of HSA in blood serum with a sensitivity limit of 3 nM. Notably, the Sq dye in solution state is nonselective and responds to any thiol-containing proteins and small molecules. The sensing mechanism involves HSA specific controlled disassembly of the Sq nanoparticles to the molecular dye by a noncovalent binding process and its subsequent reaction with the thiol moiety of the protein, triggering the green emission of a dormant fluorophore present in the dye. This study demonstrates the power of a self-assembled small molecular fluorophore for protein sensing and is a simple chemical tool for the clinical diagnosis of blood serum.

Structurally Simple and Easily Accessible Perylenes for Dye-Sensitized Solar Cells Applicable to Both 1 Sun and Dim-Light Environments.

PubMed

Chou, Hsien-Hsin; Liu, Yu-Chieh; Fang, Guanjie; Cao, Qiao-Kai; Wei, Tzu-Chien; Yeh, Chen-Yu

2017-11-01

The need for low-cost and highly efficient dyes for dye-sensitized solar cells under both the sunlight and dim light environments is growing. We have devised GJ-series push-pull organic dyes which require only four synthesis steps. These dyes feature a linear molecular structure of donor-perylene-ethynylene-arylcarboxylic acid, where donor represents N,N-diarylamino group and arylcarboxylic groups represent benzoic, thienocarboxylic, 2-cyano-3-phenylacrylic, 2-cyano-3-thienoacrylic, and 4-benzo[c][1,2,5]thiadiazol-4-yl-benzoic groups. In this study, we demonstrated that a dye without tedious and time-consuming synthesis efforts can perform efficiently. Under the illumination of AM1.5G simulated sunlight, the benzothiadiazole-benzoic-containing GJ-BP dye shows the best power conversion efficiency (PCE) of 6.16% with V OC of 0.70 V and J SC of 11.88 mA cm -2 using liquid iodide-based electrolyte. It also shows high performance in converting light of 6000 lx light intensity, that is, incident power of ca. 1.75 mW cm -2 , to power output of 0.28 mW cm -2 which equals a PCE of 15.79%. Interestingly, the benzoic-containing dye GJ-P with a simple molecular structure has comparable performance in generating power output of 0.26 mW cm -2 (PCE of 15.01%) under the same condition and is potentially viable toward future application.

Comparative performance of a genetically-encoded voltage indicator and a blue voltage sensitive dye for large scale cortical voltage imaging

PubMed Central

Mutoh, Hiroki; Mishina, Yukiko; Gallero-Salas, Yasir; Knöpfel, Thomas

2015-01-01

Traditional small molecule voltage sensitive dye indicators have been a powerful tool for monitoring large scale dynamics of neuronal activities but have several limitations including the lack of cell class specific targeting, invasiveness and difficulties in conducting longitudinal studies. Recent advances in the development of genetically-encoded voltage indicators have successfully overcome these limitations. Genetically-encoded voltage indicators (GEVIs) provide sufficient sensitivity to map cortical representations of sensory information and spontaneous network activities across cortical areas and different brain states. In this study, we directly compared the performance of a prototypic GEVI, VSFP2.3, with that of a widely used small molecule voltage sensitive dye (VSD), RH1691, in terms of their ability to resolve mesoscopic scale cortical population responses. We used three synchronized CCD cameras to simultaneously record the dual emission ratiometric fluorescence signal from VSFP2.3 and RH1691 fluorescence. The results show that VSFP2.3 offers more stable and less invasive recording conditions, while the signal-to-noise level and the response dynamics to sensory inputs are comparable to RH1691 recordings. PMID:25964738

Electronic structure measurements of metal-organic solar cell dyes using x-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Johnson, Phillip S.

The focus of this thesis is twofold: to report the results of X-ray absorption studies of metal-organic dye molecules for dye-sensitized solar cells and to provide a basic training manual on X-ray absorption spectroscopy techniques and data analysis. The purpose of our research on solar cell dyes is to work toward an understanding of the factors influencing the electronic structure of the dye: the choice of the metal, its oxidation state, ligands, and cage structure. First we study the effect of replacing Ru in several common dye structures by Fe. First-principles calculations and X-ray absorption spectroscopy at the C 1s and N 1s edges are combined to investigate transition metal dyes in octahedral and square planar N cages. Octahedral molecules are found to have a downward shift in the N 1s-to-pi* transition energy and an upward shift in C 1s-to-pi* transition energy when Ru is replaced by Fe, explained by an extra transfer of negative charge from Fe to the N ligands compared to Ru. For the square planar molecules, the behavior is more complex because of the influence of axial ligands and oxidation state. Next the crystal field parameters for a series of phthalocyanine and porphyrins dyes are systematically determined using density functional calculations and atomic multiplet calculations with polarization-dependent X-ray absorption spectra. The polarization dependence of the spectra provides information on orbital symmetries which ensures the determination of the crystal field parameters is unique. A uniform downward scaling of the calculated crystal field parameters by 5-30% is found to be necessary to best fit the spectra. This work is a part of the ongoing effort to design and test new solar cell dyes. Replacing the rare metal Ru with abundant metals like Fe would be a significant advance for dye-sensitized solar cells. Understanding the effects of changing the metal centers in these dyes in terms of optical absorption, charge transfer, and electronic structure enables the systematic design of new dyes using less expensive materials.

Lessons learned: from dye-sensitized solar cells to all-solid-state hybrid devices.

PubMed

Docampo, Pablo; Guldin, Stefan; Leijtens, Tomas; Noel, Nakita K; Steiner, Ullrich; Snaith, Henry J

2014-06-25

The field of solution-processed photovoltaic cells is currently in its second spring. The dye-sensitized solar cell is a widely studied and longstanding candidate for future energy generation. Recently, inorganic absorber-based devices have reached new record efficiencies, with the benefits of all-solid-state devices. In this rapidly changing environment, this review sheds light on recent developments in all-solid-state solar cells in terms of electrode architecture, alternative sensitizers, and hole-transporting materials. These concepts are of general applicability to many next-generation device platforms. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Can nitro groups really anchor onto TiO 2? Case study of dye-to-TiO 2 adsorption using azo dyes with NO 2 substituents

DOE PAGES

Zhang, Lei; Cole, Jacqueline M.

2016-06-21

The nitro group has recently been suggested as a new type of anchor for dye-sensitized solar cells (DSSCs) and has shown promising optoelectronic properties. Considering the excellent electron withdrawing ability of the nitro group and wider materials selection brought about by this substituent, it is helpful to evaluate the interfacial structures and photophysics of more organic dyes where NO 2 poses as the dye-to-TiO 2 anchor. A computational study on a family of azo dyes bearing a nitro group is presented in this paper, where the effect of certain side groups on their optical properties is examined. Both isolated dyemore » molecules and dye/TiO 2 nanocomposites are studied via density functional theory and time-dependent density functional theory, with complementary experimental UV/vis absorption spectroscopy and photovoltaic device testing. Results demonstrate that these nitro-containing dyes prefer a monodentate anchoring mode on a TiO 2 cluster. These nitro dyes reveal weak, but non-negligible, adsorption onto TiO 2; yet, very low photovoltaic performance once incorporated into a DSSC device. Finally, this poor delivery of nitro groups as DSSC anchors is ostensibly inconsistent with previous findings; but is rationalized via the “auxiliary anchor” concept.« less

Discovery of black dye crystal structure polymorphs: Implications for dye conformational variation in dye-sensitized solar cells

DOE PAGES

Cole, Jacqueline M.; Low, Kian Sing; Gong, Yun

2015-11-24

Here, we present the discovery of a new crystal structure polymorph (1) and pseudopolymorph (2) of the Black Dye, one of the world’s leading dyes for dye-sensitized solar cells, DSSCs (10.4% device performance efficiency). This reveals that Black Dye molecules can adopt multiple low-energy conformers. This is significant since it challenges existing models of the Black Dye···TiO 2 adsorption process that renders a DSSC working electrode; these have assumed a single molecular conformation that refers to the previously reported Black Dye crystal structure (3). The marked structural differences observed between 1, 2, and 3 make the need for modeling multiplemore » conformations more acute. Additionally, the ordered form of the Black Dye (1) provides a more appropriate depiction of its anionic structure, especially regarding its anchoring group and NCS bonding descriptions. The tendency toward NCS ligand isomerism, evidenced via the disordered form 2, has consequences for electron injection and electron recombination in Black Dye embedded DSSC devices. Dyes 2 and 3 differ primarily by the absence or presence of a solvent of crystallization, respectively; solvent environment effects on the dye are thereby elucidated. This discovery of multiple Black Dye conformers from diffraction, with atomic-level definition, complements recently reported nanoscopic evidence for multiple dye conformations existing at a dye···TiO 2 interface, for a chemically similar DSSC dye; those results emanated from imaging and spectroscopy, but were unresolved at the submolecular level. Taken together, these findings lead to the general notion that multiple dye conformations should be explicitly considered when modeling dye···TiO 2 interfaces in DSSCs, at least for ruthenium-based dye complexes.« less

Ground and excited state properties of high performance anthocyanidin dyes-sensitized solar cells in the basic solutions

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

Prima, Eka Cahya; Computational Material Design and Quantum Engineering Laboratory, Engineering Physics, Institut Teknologi Bandung; International Program on Science Education, Universitas Pendidikan Indonesia

2015-09-30

The aglycones of anthocyanidin dyes were previously reported to form carbinol pseudobase, cis-chalcone, and trans-chalcone due to the basic levels. The further investigations of ground and excited state properties of the dyes were characterized using density functional theory with PCM(UFF)/B3LYP/6-31+G(d,p) level in the basic solutions. However, to the best of our knowledge, the theoretical investigation of their potential photosensitizers has never been reported before. In this paper, the theoretical photovoltaic properties sensitized by dyes have been successfully investigated including the electron injections, the ground and excited state oxidation potentials, the estimated open circuit voltages, and the light harvesting efficiencies. Themore » results prove that the electronic properties represented by dyes’ LUMO-HOMO levels will affect to the photovoltaic performances. Cis-chalcone dye is the best anthocyanidin aglycone dye with the electron injection spontaneity of −1.208 eV, the theoretical open circuit voltage of 1.781 V, and light harvesting efficiency of 56.55% due to the best HOMO-LUMO levels. Moreover, the ethanol solvent slightly contributes to the better cell performance than the water solvent dye because of the better oxidation potential stabilization in the ground state as well as in the excited state. These results are in good agreement with the known experimental report that the aglycones of anthocyanidin dyes in basic solvent are the high potential photosensitizers for dye-sensitized solar cell.« less

Photophysical investigations of squaraine and cyanine dyes and their interaction with bovine serum albumin

NASA Astrophysics Data System (ADS)

Saikiran, M.; Sato, D.; Pandey, S. S.; Kato, T.

2016-04-01

A model far-red sensitive symmetrical squaraine dye (SQ-3) and unsymmetrical near infra-red sensitive cyanine dye (UCD-1) bearing direct-COOH functionalized indole ring were synthesized, characterized and subjected to photophysical investigations including their interaction with bovine serum albumin (BSA) as a model protein in phosphate buffer solution (PBS). Both of the dyes exhibit strong interaction with BSA in phosphate buffer with high apparent binding constant. A judicious tuning of hydrophobic main backbone with reactive functionality for associative interaction with active site of BSA has been found to be necessary for BSA detection in PBS.

Hybrid Dye-Sensitized Solar Cells Consisting of Double Titania Layers for Harvesting Light with Wide Range of Wavelengths

NASA Astrophysics Data System (ADS)

Sadamasu, Kengo; Inoue, Takafumi; Ogomi, Yuhei; Pandey, Shyam S.; Hayase, Shuzi

2011-02-01

We report a hybrid dye-sensitized solar cell consisting of double titania layers (top and bottom layers) stained with two dyes. A top layer fabricated on a glass was mechanically pressed with a bottom layer fabricated on a glass cloth. The glass cloth acts as a supporter of a porous titania layer as well as a holder of electrolyte. The incident photon to current efficiency (IPCE) curve had two peaks corresponding to those of the two dyes, which demonstrates that electrons are collected from both the top and bottom layers.

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

Koch, T.H.

Coumarin laser dyes upon excitation degrade to produce products that absorb at the lasing wavelength. This results in attenuation of dye laser output through interference of stimulated emission. The roles of singlet oxygen and excitation intensity on dye degradation were explored. Singlet oxygen is formed but its reactions with the dye do not appear to be a major cause of dye laser output deterioration. High light intensity results in dye-sensitized, solvent oligomerization to yield materials that interfere with dye-stimulated emission. 1, 4-Diazabicyclo2,2,2octane (DABCO)inhibits this oligomerization.

Spectroscopic (FT-IR, FT-Raman and UV-Visible) investigations, NMR chemical shielding anisotropy (CSA) parameters of 2,6-Diamino-4-chloropyrimidine for dye sensitized solar cells using density functional theory.

PubMed

Gladis Anitha, E; Joseph Vedhagiri, S; Parimala, K

2015-02-05

The molecular structure, geometry optimization, vibrational frequencies of organic dye sensitizer 2,6-Diamino-4-chloropyrimidine (DACP) were studied based on Hartree-Fock (HF) and density functional theory (DFT) using B3LYP methods with 6-311++G(d,p) basis set. Ultraviolet-Visible (UV-Vis) spectrum was investigated by time dependent DFT (TD-DFT). Features of the electronic absorption spectrum in the UV-Visible regions were assigned based on TD-DFT calculation. The absorption bands are assigned to transitions. The interfacial electron transfer between semiconductor TiO2 electrode and dye sensitizer DACP is due to an electron injection process from excited dye to the semiconductor's conduction band. The observed and the calculated frequencies are found to be in good agreement. The energies of the frontier molecular orbitals (FMOS) have also been determined. The chemical shielding anisotropic (CSA) parameters are calculated from the NMR analysis, Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparative proteomic analysis using samples obtained with laser microdissection and saturation dye labelling.

PubMed

Wilson, Kate E; Marouga, Rita; Prime, John E; Pashby, D Paul; Orange, Paul R; Crosier, Steven; Keith, Alexander B; Lathe, Richard; Mullins, John; Estibeiro, Peter; Bergling, Helene; Hawkins, Edward; Morris, Christopher M

2005-10-01

Comparative proteomic methods are rapidly being applied to many different biological systems including complex tissues. One pitfall of these methods is that in some cases, such as oncology and neuroscience, tissue complexity requires isolation of specific cell types and sample is limited. Laser microdissection (LMD) is commonly used for obtaining such samples for proteomic studies. We have combined LMD with sensitive thiol-reactive saturation dye labelling of protein samples and 2-D DIGE to identify protein changes in a test system, the isolated CA1 pyramidal neurone layer of a transgenic (Tg) rat carrying a human amyloid precursor protein transgene. Saturation dye labelling proved to be extremely sensitive with a spot map of over 5,000 proteins being readily produced from 5 mug total protein, with over 100 proteins being significantly altered at p < 0.0005. Of the proteins identified, all showed coherent changes associated with transgene expression. It was, however, difficult to identify significantly different proteins using PMF and MALDI-TOF on gels containing less than 500 mug total protein. The use of saturation dye labelling of limiting samples will therefore require the use of highly sensitive MS techniques to identify the significantly altered proteins isolated using methods such as LMD.

Exploring the relevance of thiophene rings as bridge unit in acceptor-bridge-donor dyes on self-aggregation and performance in DSSCs.

PubMed

Zarate, Ximena; Saavedra-Torres, Mario; Rodriguez-Serrano, Angela; Gomez, Tatiana; Schott, Eduardo

2018-04-30

The possibility of dye charge recombination in DSSCs remains a challenge for the field. This consists of: (a) back-transfer from the TiO 2 to the oxidized dye and (b) intermolecular electron transfer between dyes. The latter is attributed to dye aggregation due to dimeric conformations. This leads to poor electron injection which decreases the photocurrent conversion efficiency. Most organic sensitizers are characterized by an Acceptor-Bridge-Donor (A-Bridge-D) arrangement that is commonly employed to provide charge separation and, therefore, lowering the unwanted back-transfer. Here, we address the intermolecular electron transfer by studying the dimerization and photovoltaic performance of a group of A-Bridge-D structured dyes. Specifically, eight famous sulfur containing π-bridges were analyzed (A and D remained fixed). Through quantum mechanical and molecular dynamics approaches, it was found that the formation of weakly stabilized dimers is allowed. The dyes with covalently bonded and fused thiophene rings as Bridges, 6d and 7d as well as 8d with a fluorene, would present high aggregation and, therefore, high probability of recombination processes. Conversely, using TiO 2 cluster and surface models, delineated the shortest bridges to improve the adsorption energy and the stability of the system. Finally, the elongation of the bridge up to 2 and 3 units and their photovoltaic parameters were studied. These results showed that all the sensitizers are able to provide similar photocurrent outcomes, regardless of whether the bridge is elongated. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Optimizing Ionic Electrolytes for Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Fan, Xiaojuan; Hall, Sarah

2009-03-01

Dye-sensitized solar cells DSSCs provide next generation, low cost, and easy fabrication photovoltaic devices based on organic sensitizing molecules, polymer gel electrolyte, and metal oxide semiconductors. One of the key components is the solvent-free ionic liquid electrolyte that has low volatility and high stability. We report a rapid and low cost method to fabricate ionic polymer electrolyte used in DSSCs. Poly(ethylene oxide) (PEO) is blended with imidazolinium salt without any chemical solvent to form a gel electrolyte. Uniform and crack-free porous TiO2 thin films are sensitized by porphrine dye covered by the synthesized gel electrolyte. The fabricated DSSCs are more stable and potentially increase the photo-electricity conversion efficiency.

Optically transparent FTO-free cathode for dye-sensitized solar cells.

PubMed

Kavan, Ladislav; Liska, Paul; Zakeeruddin, Shaik M; Grätzel, Michael

2014-12-24

The woven fabric containing electrochemically platinized tungsten wire is an affordable flexible cathode for liquid-junction dye-sensitized solar cells with the I3(-)/I(-) redox mediator and electrolyte solution consisting of ionic liquids and propionitrile. The fabric-based electrode outperforms the thermally platinized FTO in serial ohmic resistance and charge-transfer resistance for triiodide reduction, and it offers comparable or better optical transparency in the visible and particularly in the near-IR spectral region. The electrode exhibits good stability during electrochemical loading and storage at open circuit. The dye-sensitized solar cells with a C101-sensitized titania photoanode and either Pt-W/PEN or Pt-FTO cathodes show a comparable performance.

Theoretical study of new potential semiconductor surfaces performance for dye sensitized solar cell usage: TiO2-B (001), (100) and H2Ti3O7 (100)

NASA Astrophysics Data System (ADS)

German, Estefania; Faccio, Ricardo; Mombrú, Álvaro W.

2017-12-01

Hydrogen titanate (H2Ti3O7) and TiO2-B polymorph are potential surfaces identified experimentally in the last years, which need to be analyzed. To study their performance as surfaces for dye sensitized solar cells (DSSC), a set of dye adsorption configurations were evaluated on them, as model dye the small and organic catechol molecule was used. We have calculated adsorption geometry, energy, electronic transfer from dye to semiconductor adsorbent and frontier orbitals by means of density functional theory (DFT). Results show that vacancy-like defected H2Ti3O7 (100) and TiO2-B (100) surfaces present favorable adsorption energies. Finally, an adequate energy level alignment make both surfaces prone to be adequate for direct electron transfer upon excitation, from catechol to the conduction band of the semiconductors, with bands located in the Visible region of the electromagnetic spectrum. Additionally, the band structure alignment indicates an increase in the open circuit voltage, in reference to I2/I3- redox pair potential. All these characteristics make hydrogen titanate (H2Ti3O7) and TiO2-B polymorph promising for DSSC applications.

Effect of photoanode thickness on electrochemical performance of dye sensitized solar cell

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

Khatani, Mehboob, E-mail: mkhatani@hotmail.com; Hamid, Nor Hisham, E-mail: hishmid@petronas.com.my; Sahmer, Ahmed Zahrin, E-mail: azclement@yahoo.com

2015-07-22

The thickness of photoanode is crucial as it adsorbed a large amount of dye molecules that provide electrons for generation of electricity in dye sensitized solar cell (DSC). Thus, in order to realize the practical application of DSC, study on various thickness of photoanode need to be carried out to analyze its effect on the electrochemical behavior of dye sensitized solar cell. To enhance the conversion efficiency, an additional layer of TiO{sub 2} using TiCl{sub 4} treatment was deposited prior to the deposition of the photoanode (active area of 1cm{sup 2}) with the thickness of 6, 12, 18, 24, andmore » 30 µm on fluorine doped tin oxide (FTO) glass substrate. The resulting photoanode after the soak in N719 dye for more than 12hrs were used to be assembled in a test cell in combination with liquid electrolyte and counter electrode. The fabricated cells were characterized by solar simulator, ultraviolet-visible spectroscopy (UV-VIS), and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy (SEM) was used to approximate the thickness of photoanode. An optimum power conversion efficiency of 4.54% was obtained for the cell fabricated with 18 µm photoanode thickness. This is attributed to the reduced resistance related to electron transport in the TiO{sub 2}/dye/electrolyte interface as proven by the EIS result. This led to the reduction of internal resistance, the increase in the electron life time and the improvement in the conversion efficiency.« less

Para-phenylenediamine allergy: current perspectives on diagnosis and management

PubMed Central

Mukkanna, Krishna Sumanth; Stone, Natalie M; Ingram, John R

2017-01-01

Para-phenylenediamine (PPD) is the commonest and most well-known component of hair dyes. Oxidative hair dyes and dark henna temporary tattoos contain PPD. Individuals may be sensitized to PPD by temporary henna tattooing in addition to dyeing their hair. PPD allergy can cause severe reactions and may result in complications. In recent years, frequency of positive patch test reactions to PPD has been increasing. Cross-sensitization to other contact allergens may occur, in particular to other hair dye components. Hairdressers are at a high risk for PPD allergy and require counseling regarding techniques to minimize exposure and protective measures while handling hair dye. We focus this review on the current perspectives of diagnosis and management of PPD allergy. PMID:28176912

Bi-anchoring organic sensitizers of type D-(π-A)2 comprising thiophene-2-acetonitrile as π-spacer and malonic acid as electron acceptor for dye sensitized solar cell applications

NASA Astrophysics Data System (ADS)

Reddy, Gachumale Saritha; Ramkumar, Sekar; Asiri, Abdullah M.; Anandan, Sambandam

2015-06-01

Two new bi-anchoring organic sensitizers of type D-(π-A)2 comprising the identical π-spacer (thiophene-2-acetonitrile) and electron acceptor (malonic acid) but different aryl amine as electron donors (diphenylamine and carbazole) were synthesized, characterized and fabricated metal free dye-sensitized solar cell devices. The intra molecular charge transfer property and electrochemical property of these dyes were investigated by molecular absorption, emission, cyclic voltammetric experiments and in addition, quantum chemical calculation studies were performed to provide sufficient driving force for the electron injection into the conduction band of TiO2 which leads to efficient charge collection. Among the fabricated devices, carbazole based device exhibits high current conversion efficiency (η = 4.7%) with a short circuit current density (JSC) 15.3 mA/cm2, an open circuit photo voltage (VOC) of 0.59 V and a fill factor of 0.44 under AM 1.5 illumination (85 mW/cm2) compared to diphenylamine based device.

Time-dependent efficiency measurements of donor-acceptor, dye-sensitized polymer solar cells

NASA Astrophysics Data System (ADS)

Bandaccari, Kyle; Chesmore, Grace; Tajalli-Tehrani Valverde, Parisa; Bugaj, Mitchel; McNelis, Brian; Barber, Richard, Jr.

The fullerene/polymer active layer pairing of PCBM/P3HT has become the model system within the field of polymer solar cell research. A large body of work concerned with reporting improved efficiencies for this system exists, but truly quantitative studies of device lifetime and long-term degradation tendencies are much rarer. Here, we report the effects of two donor-acceptor diazo dye sensitizers on efficiency and lifetime upon addition into the PCBM/P3HT active layer at varied concentrations. The electrical and efficiency measurements were supplemented by time-dependent UV-visible spectroscopy studies and morphology investigations via atomic-force microscopy (AFM). This pairing with spectroscopy offers an internal check on the data as the rate of change in absorbance of the active layer correlates almost exactly to the rate of power conversion efficiency decrease. Additionally, AFM imaging reveals different morphology patterns when dye concentrations and functionalities change. Such observations suggest that such small-molecule sensitizers exert yet undetermined effects on the organization of components within the active layer at the molecular level.

Dimerization of Organic Dyes on Luminescent Gold Nanoparticles for Ratiometric pH Sensing.

PubMed

Sun, Shasha; Ning, Xuhui; Zhang, Greg; Wang, Yen-Chung; Peng, Chuanqi; Zheng, Jie

2016-02-12

Synergistic effects arising from the conjugation of organic dyes onto non-luminescent metal nanoparticles (NPs) have greatly broadened their applications in both imaging and sensing. Herein, we report that conjugation of a well-known pH-insensitive dye, tetramethyl-rhodamine (TAMRA), to pH-insensitive luminescent gold nanoparticles (AuNPs) can lead to an ultrasmall nanoindicator that can fluorescently report local pH in a ratiometric way. Such synergy originated from the dimerization of TAMRA on AuNPs, of which geometry was very sensitive to surface charges of the AuNPs and can be reversely modulated through protonation of surrounding glutathione ligands. Not limited to pH-insensitive dyes, this pH-dependent dimerization can also enhance the pH sensitivity of fluorescein, a well-known pH-sensitive dye, within a larger pH range, opening up a new pathway to design ultrasmall fluorescent ratiometric nanoindicators with tunable wavelengths and pH response ranges. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design of new triphenylamine-sensitized solar cells: a theoretical approach.

PubMed

Preat, Julien; Jacquemin, Denis; Perpète, Eric A

2010-07-15

This work reports a theoretical study of the photovoltaic properties of a series of original conjugated metal-free organic dyes containing the triphenylamine (TPA) moiety. These compounds have recently been develop for dye sensitized solar cells (DSSCs). Our (TD)DFT-based procedure made it possible to get insights into the geometrical and electronic structures of the dyes and to unravel the structural modifications optimizing the properties of TPA-based DSSCs. In particular, we aimed at improving the electron injection process as well as the light harvesting efficiency of the dyes. On the other hand, molecular dynamic (MD) investigations of the kinetics of the regeneration step have been performed for both "classical" (CHCl(3)/I(3)(-)/I(-)/Li(+)) and iodide imidazolium-based solvent-free electrolytes (DMII(+)/I(-)). The MD simulations helped to understand the regeneration mechanism for the solvent-free electrolyte: it combines the DMII(+)/DMII(0) couple to the I(3)(-)/I(-) redox system which acts as a "mediator".

Comparison of the ionizing radiation effects on cochineal, annatto and turmeric natural dyes

NASA Astrophysics Data System (ADS)

Cosentino, Helio M.; Takinami, Patricia Y. I.; del Mastro, Nelida L.

2016-07-01

As studies on radiation stability of food dyes are scarce, commercially important natural food grade dyes were evaluated in terms of their sensitivity against gamma ionizing radiation. Cochineal, annatto and turmeric dyes with suitable concentrations were subjected to increasing doses up to 32 kGy and analyzed by spectrophotometry and capillary electrophoresis. The results showed different pattern of absorbance versus absorbed dose for the three systems. Carmine, the glucosidal coloring matter from the scale insect Coccus cacti L., Homoptera (cochineal) remained almost unaffected by radiation up to doses of about 32 kGy (absorbance at 494 nm). Meanwhile, at that dose, a plant-derived product annatto or urucum (Bixa orellana L.) tincture presented a nearly 58% reduction in color intensity. Tincture of curcumin (diferuloylmethane) the active ingredient in the eastern spice turmeric (Curcuma longa) showed to be highly sensitive to radiation when diluted. These data shall be taken in account whenever food products containing these food colors were going to undergo radiation processing.

Hydroxamate anchors for improved photoconversion in dye-sensitized solar cells.

PubMed

Brewster, Timothy P; Konezny, Steven J; Sheehan, Stafford W; Martini, Lauren A; Schmuttenmaer, Charles A; Batista, Victor S; Crabtree, Robert H

2013-06-03

We present the first analysis of performance of hydroxamate linkers as compared to carboxylate and phosphonate groups when anchoring ruthenium-polypyridyl dyes to TiO2 surfaces in dye-sensitized solar cells (DSSCs). The study provides fundamental insight into structure/function relationships that are critical for cell performance. Our DSSCs have been produced by using newly synthesized dye molecules and characterized by combining measurements and simulations of experimental current density-voltage (J-V) characteristic curves. We show that the choice of anchoring group has a direct effect on the overall sunlight-to-electricity conversion efficiency (η), with hydroxamate anchors showing the best performance. Solar cells based on the pyridyl-hydroxamate complex exhibit higher efficiency since they suppress electron transfer from the photoanode to the electrolyte and have superior photoinjection characteristics. These findings suggest that hydroxamate anchoring groups should be particularly valuable in DSSCs and photocatalytic applications based on molecular adsorbates covalently bound to semiconductor surfaces. In contrast, analogous acetylacetonate anchors might undergo decomposition under similar conditions suggesting limited potential in future applications.

Observation of Significant enhancement in the efficiency of a DSSC by InN nanoparticles over TiO 2-nanoparticle films

NASA Astrophysics Data System (ADS)

Wang, Tsai-Te; Raghunath, P.; Lu, Yun-Fang; Liu, Yu-Chang; Chiou, Chwei-Huawn; Lin, M. C.

2011-06-01

We have studied the effect of InN deposited over TiO2 nanoparticle (NP) films on the performance of dye-sensitized solar cells (DSSCs) using N3 dye with I/I3- electrolyte. A 10-20% increase in efficiency was observed for InN deposited, N3 sensitized 5-8.5 μm thick TiO2 films as compared to similar non-treated films. The deposition of InN was carried out in the temperature range of 573-723 K organometallic chemical vapor deposition (OMCVD). Spectral shifts and DFT calculations with a model anchoring group (R‧COOH) both suggest binding of the N3 dye directly to both InN and the InN/TiO2 sites.

Solid state photon upconversion utilizing thermally activated delayed fluorescence molecules as triplet sensitizer

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

Wu, Tony C.; Congreve, Daniel N.; Baldo, Marc A., E-mail: baldo@mit.edu

2015-07-20

The ability to upconvert light is useful for a range of applications, from biological imaging to solar cells. But modern technologies have struggled to upconvert incoherent incident light at low intensities. Here, we report solid state photon upconversion employing triplet-triplet exciton annihilation in an organic semiconductor, sensitized by a thermally activated-delayed fluorescence (TADF) dye. Compared to conventional phosphorescent sensitizers, the TADF dye maximizes the wavelength shift in upconversion due to its small singlet-triplet splitting. The efficiency of energy transfer from the TADF dye is 9.1%, and the conversion yield of sensitizer exciton pairs to singlet excitons in the annihilator ismore » 1.1%. Our results demonstrate upconversion in solid state geometries and with non-heavy metal-based sensitizer materials.« less

Multiple electron injection dynamics in linearly-linked two dye co-sensitized nanocrystalline metal oxide electrodes for dye-sensitized solar cells.

PubMed

Shen, Qing; Ogomi, Yuhei; Park, Byung-wook; Inoue, Takafumi; Pandey, Shyam S; Miyamoto, Akari; Fujita, Shinsuke; Katayama, Kenji; Toyoda, Taro; Hayase, Shuzi

2012-04-07

Understanding the electron transfer dynamics at the interface between dye sensitizer and semiconductor nanoparticle is very important for both a fundamental study and development of dye-sensitized solar cells (DSCs), which are a potential candidate for next generation solar cells. In this study, we have characterized the ultrafast photoexcited electron dynamics in a newly produced linearly-linked two dye co-sensitized solar cell using both a transient absorption (TA) and an improved transient grating (TG) technique, in which tin(IV) 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine (NcSn) and cis-diisothiocyanato-bis(2,2'-bipyridyl-4,4'-dicarboxylato)ruthenium(II) bis(tetrabutylammonium) (N719) are molecularly and linearly linked and are bonded to the surface of a nanocrystalline tin dioxide (SnO(2)) electrode by a metal-O-metal linkage (i.e. SnO(2)-NcSn-N719). By comparing the TA and TG kinetics of NcSn, N719, and hybrid NcSn-N719 molecules adsorbed onto both of the SnO(2) and zirconium dioxide (ZrO(2)) nanocrystalline films, the forward and backward electron transfer dynamics in SnO(2)-NcSn-N719 were clarified. We found that there are two pathways for electron injection from the linearly-linked two dye molecules (NcSn-N719) to SnO(2). The first is a stepwise electron injection, in which photoexcited electrons first transfer from N719 to NcSn with a transfer time of 0.95 ps and then transfer from NcSn to the conduction band (CB) of SnO(2) with two timescales of 1.6 ps and 4.2 ps. The second is direct photoexcited electron transfer from N719 to the CB of SnO(2) with a timescale of 20-30 ps. On the other hand, back electron transfer from SnO(2) to NcSn is on a timescale of about 2 ns, which is about three orders of magnitude slower compared to the forward electron transfer from NcSn to SnO(2). The back electron transfer from NcSn to N719 is on a timescale of about 40 ps, which is about one order slower compared to the forward electron transfer from N719 to NcSn. These results demonstrate that photoexcited electrons can be effectively injected into SnO(2) from both of the N719 and NcSn dyes.

Feasibility of using RH795 dye for photoacoustic imaging of neuro-electrical activity

NASA Astrophysics Data System (ADS)

Rasheed, Nashaat; Cressman, John R.; Chitnis, Parag V.

2017-02-01

Currently, the most researched noninvasive approach for monitoring neuro-electrical activity involves opticalfluorescence imaging, which suffers from limited imaging penetration. We propose an alternative approach, photoacoustic imaging (PAI) of biopotentials, that relies on transient absorption of light by voltage-sensitive probes and subsequent generation/detection of ultrasound. PAI-based voltage imaging approach can offer the same advantages as the fluorescence imaging in terms of sensitivity and molecular specificity, but it also can significantly extend the imaging depth. In this pilot study we are investigating the feasibility of photoacoustically visualizing biopotentials in rat pheochromocytoma (PC12) cells tagged with voltage-sensitive styrylpyridinium dye, RH795. A change in the intramembrane potential was induced in PC12 cells by adding tetraphenylborate (TPB) to the cell culture. A custommade absorption spectrophotometer was used to verify the change in optical absorption of RH795 dye as a result of TPBinduced electrical fields. Absorption spectra recorded before and after the addition of 100 μM TPB exhibited a wavelength shift of the absorption peak (approximately 510 nm to 550 nm) as well as an increase in the overall magnitude of absorption in the wavelength range of 500-1000 nm. The absorption spectral measurements indicated that RH795 is a good candidate as a voltage-sensitive dye for photoacoustically tracking changes in cell-membrane potential.

Effect of electron withdrawing unit for dye-sensitized solar cell based on D-A-π-A organic dyes

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

Kwon, Dong Yuel; Chang, Dong Min; Kim, Young Sik, E-mail: youngkim@hongik.ac.kr

2014-10-15

Highlights: • To gain the red-shifted absorption spectra, withdrawing unit was substituted in dye. • By the introduction of additional withdrawing unit, LUMOs level of dye are decreased. • Decreasing LUMOs level of dye caused the red-shifted absorption spectra of dye. • Novel acceptor, DCRD, showed better photovoltaic properties than cyanoacetic acid. - Abstract: In this work, two novel D-A-π-A dye sensitizers with triarylamine as an electron donor, isoindigo and cyano group as electron withdrawing units and cyanoacetic acid and 2-(1,1-dicyanomethylene) rhodanine as an electron acceptor for an anchoring group (TICC, TICR) were designed and investigated with the ID6 dyemore » as the reference. The difference in HOMO and LUMO levels were compared according to the presence or absence of isoindigo in ID6 (TC and ID6). To gain insight into the factors responsible for photovoltaic performance, we used density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations. Owing to different LUMO levels for each acceptor, the absorption band and molar extinction coefficient of each dye was different. Among the dyes, TICR showed more red-shifted and broader absorption spectra than other dyes and had a higher molar extinction coefficient than the reference. It is expected that TICR would show better photovoltaic properties than the other dyes, including the reference dye.« less

Benzo[a]carbazole-Based Donor-π-Acceptor Type Organic Dyes for Highly Efficient Dye-Sensitized Solar Cells.

PubMed

Qian, Xing; Zhu, Yi-Zhou; Chang, Wen-Ying; Song, Jian; Pan, Bin; Lu, Lin; Gao, Huan-Huan; Zheng, Jian-Yu

2015-05-06

A novel class of metal-free organic dyes based on benzo[a]carbazole have been designed, synthesized, and used in dye-sensitized solar cells for the first time. These types of dyes consisted of a cyanoacrylic acid moiety as the electron acceptor/anchoring group and different electron-rich spacers such as thiophene (JY21), furan (JY22), and oligothiophene (JY23) as the π-linkers. The photophysical, electrochemical, and photovoltaic properties, as well as theoretical calculations of these dyes were investigated. The photovoltaic performances of these dyes were found to be highly relevant to the π-conjugated linkers. In particular, dye JY23 exhibited a broad IPCE response with a photocurrent signal up to about 740 nm covering the most region of the UV-visible light. A DSSC based on JY23 showed the best photovoltaic performance with a Jsc of 14.8 mA cm(-2), a Voc of 744 mV, and a FF of 0.68, achieving a power conversion efficiency of 7.54% under standard AM 1.5 G irradiation.

Co-sensitized natural dyes potentially used to enhance light harvesting capability

NASA Astrophysics Data System (ADS)

Amelia, R.; Sawitri, D.; Risanti, D. D.

2015-01-01

We present the photoelectrochemical properties of dye-sensitized solar cells using natural pigments containing anthocyanins, betalains, and caroteins. The dyes were adsorbed by a photoanode that was fabricated from nanocrystalline TiO2 on transparent conductive glass. TiO2 comprises of 100% anatase and 90:10 anatase:rutile fraction. The dyes extracted from mangosteen pericarp, Musa aromatica pericarp, Celosia cristata flower and red beet root were characterized through UV-vis and IPCE. The effectiveness of the dyes was explained through photocurrent as a function of incident light power. It was found that the cocktail and multilayered dyes comprised of anthocyanins and caroteins is beneficial to obtain high photocurrent, whereas betalains is not recommended to be applied on untreated TiO2. Due to the bandgap properties of rutile and anatase, the presence of 10% rutile in TiO2 is favourable to further enhance the electron transport.

Revealing the influence of Cyano in Anchoring Groups of Organic Dyes on Adsorption Stability and Photovoltaic Properties for Dye-Sensitized Solar Cells.

PubMed

Chen, Wei-Chieh; Nachimuthu, Santhanamoorthi; Jiang, Jyh-Chiang

2017-07-10

Determining an ideal adsorption configuration for a dye on the semiconductor surface is an important task in improving the overall efficiency of dye-sensitized solar cells. Here, we present a detailed investigation of different adsorption configurations of designed model dyes on TiO 2 anatase (101) surface using first principles methods. Particularly, we aimed to investigate the influence of cyano group in the anchoring part of dye on its adsorption stability and the overall photovoltaic properties such as open circuit voltage, electron injection ability to the surface. Our results indicate that the inclusion of cyano group increases the stability of adsorption only when it adsorbs via CN with the surface and it decreases the photovoltaic properties when it does not involve in binding. In addition, we also considered full dyes based on the results of model dyes and investigated the different strength of acceptor abilities on stability and electron injection ability. Among the various adsorption configurations considered here, the bidentate bridging mode (A3) is more appropriate one which has higher electron injection ability, larger V OC value and more importantly it has higher dye loading on the surface.

Effect of The Addition of PEG and PVA Polymer for Gel Electrolytes in Dye-Sensitized Solar Cell (DSSC) with Chlorophyll as Dye Sensitizer

NASA Astrophysics Data System (ADS)

Seni, Ramadhanti S.; Puspitasari, Nurrisma; Endarko

2017-07-01

Dye-sensitized Solar Cell (DSSC) is a third-generation solar cell that consists of a working electrode, electrolyte and counter electrode. One of the most important parts of DSSC is an electrolyte that roles as a medium and regenerates the electron transport of electrons in the dye. However, the liquid electrolyte has a lack of stability in long-term use and easily evaporate or leak in DSSC. Therefore, this study aims to investigate an effect of the addition of polymer material such as PEG 1000, 4000 and PVA 60000 for fabricating a gel electrolyte to solve the problems of liquid electrolyte. The synthesized TiO2 nanoparticles used in this study was prepared using co-precipitation (CPT) method which produces TiO2 anatase phase with a crystal size of 11.1 nm. DSSC has been successfully conducted and analyzed to evaluate its performance. The results showed that the efficiency of DSSC cells using gel electrolyte prepared with PVA 60000 was better than a liquid electrolyte, PEG 1000, 4000, with the efficiency could be obtained at 0.083, 0.018, 0.033, and 0.054%, respectively. The results demonstrated that the addition PEG and/or PVA could be enhanced the performance of DSSC due to gel electrolyte produced current and voltage more stable compared to the liquid electrolyte.

Visualization of Cortical Dynamics

NASA Astrophysics Data System (ADS)

Grinvald, Amiram

2003-03-01

Recent progress in studies of cortical dynamics will be reviewed including the combination of real time optical imaging based on voltage sensitive dyes, single and multi- unit recordings, LFP, intracellular recordings and microstimulation. To image the flow of neuronal activity from one cortical site to the next, in real time, we have used optical imaging based on newly designed voltage sensitive dyes and a Fuji 128x 128 fast camera which we modified. A factor of 20-40 fold improvement in the signal to noise ratio was obtained with the new dye during in vivo imaging experiments. This improvements has facilitates the exploration of cortical dynamics without signal averaging in the millisecond time domain. We confirmed that the voltage sensitive dye signal indeed reflects membrane potential changes in populations of neurons by showing that the time course of the intracellular activity recorded intracellularly from a single neuron was highly correlated in many cases with the optical signal from a small patch of cortex recorded nearby. We showed that the firing of single cortical neurons is not a random process but occurs when the on-going pattern of million of neurons is similar to the functional architecture map which correspond to the tuning properties of that neuron. Chronic optical imaging, combined with electrical recordings and microstimulation, over a long period of times of more than a year, was successfully applied also to the study of higher brain functions in the behaving macaque monkey.

Asymmetric Zinc Phthalocyanines as Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Tunc, Gulenay; Yavuz, Yunus; Gurek, Aysegul; Canimkurbey, Betul; Kosemen, Arif; San, Sait Eren; Ahsen, Vefa

Dye-sensitized solar cells (DSSCs) have received increasing attention due to their high incident to photon efficiency, easy fabrication and low production cost . Tremendous research efforts have been devoted to the development of new and efficient sensitizers suitable for practical use. In TiO2-based DSSCs, efficiencies of up to 11.4% under simulated sunlight have been obtained with rutheniumepolypyridyl complexes. However, the main drawback of ruthenium complexes is the lack of absorption in the red region of the visible light and the high cost. For this reason, dyes with large and stable p-conjugated systems such as porphyrins and phthalocyanines are important classes of potential sensitizers for highly efficient DSSCs. Phthalocyanines (Pcs) have been widely used as sensitizers because of their improved light-harvesting properties in the far red- and near-IR spectral regions and their extraordinary robustness [1]. In this work, a series of asymmetric Zn(II) Pcs bearing a carboxylic acid group and six hexylthia groups either at the peripheral or non-peripheral positions have been designed and synthesized to investigate the influence of the COOH group and the positions of hexylthia groups on the dye-sensitized solar cell (DSSC) performance.

High-performance Förster resonance energy transfer (FRET)-based dye-sensitized solar cells: rational design of quantum dots for wide solar-spectrum utilization.

PubMed

Lee, Eunwoo; Kim, Chanhoi; Jang, Jyongsik

2013-07-29

High-performance Förster resonance energy transfer (FRET)-based dye-sensitized solar cells (DSSCs) have been successfully fabricated through the optimized design of a CdSe/CdS quantum-dot (QD) donor and a dye acceptor. This simple approach enables quantum dots and dyes to simultaneously utilize the wide solar spectrum, thereby resulting in high conversion efficiency over a wide wavelength range. In addition, major parameters that affect the FRET interaction between donor and acceptor have been investigated including the fluorescent emission spectrum of QD, and the content of deposited QDs into the TiO2 matrix. By judicious control of these parameters, the FRET interaction can be readily optimized for high photovoltaic performance. In addition, the as-synthesized water-soluble quantum dots were highly dispersed in a nanoporous TiO2 matrix, thereby resulting in excellent contact between donors and acceptors. Importantly, high-performance FRET-based DSSCs can be prepared without any infrared (IR) dye synthetic procedures. This novel strategy offers great potential for applications of dye-sensitized solar cells. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preferred Molecular Orientation of Coumarin 343 on TiO 2 Surfaces: Application to Dye-Sensitized Solar Cells

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

McCree-Grey, Jonathan; Cole, Jacqueline M.; Evans, Peter J.

2015-07-21

The dye…TiO2 interfacial structure in working electrodes of dye-sensitized solar cells (DSCs) is known to influence its photovoltaic device performance. Despite this, direct and quantitative reports of such structure remain sparse. This case study presents the application of X-ray reflectometry to determine the preferred structural orientation and molecular packing of the organic dye, coumarin 343, adsorbed onto amorphous TiO2. Results show that the dye molecules are, on average, tilted by 61.1° relative to the TiO2 surface, and are separated from each other by 8.2 Å. These findings emulate the molecular packing arrangement of a monolayer of coumarin 343 within itsmore » crystal structure. This suggests that the dye adsorbs onto TiO2 in one of its lowest energy configurations, i.e. dye…TiO2 self assembly is driven more by thermodynamic rather than kinetic means. Complementary DSC device tests illustrate that this interfacial structure compromises photovoltaic performance, unless a suitably sized co-adsorbant is interdispersed between the coumarin 343 chromophores on the TiO2 surface.« less

Impact of calcium-sensitive dyes on the beating properties and pharmacological responses of human iPS-derived cardiomyocytes using the calcium transient assay.

PubMed

Kopljar, Ivan; Hermans, An N; Teisman, Ard; Gallacher, David J; Lu, Hua Rong

Calcium-based screening of hiPS-CMs is a useful preclinical safety evaluation platform with the ability to generate robust signals that facilitates high-throughput screening and data analysis. However, due to the potential inherent toxicities, it is important to understand potential effects of different calcium-sensitive dyes on the hiPS-CMs model. We compared three calcium-sensitive fluorescence dyes (Cal520, ACTOne and Calcium 5) for their impact on the variability, the beating properties and the pharmacological responses of hiPS-CMs using the Hamamatsu FDSS/μCell imaging platform. Direct effects of three dyes on the electrophysiological properties of hiPS-CMs were evaluated with the multi-electrode array (MEA) Axion Maestro platform. We propose a specific experimental protocol for each dye which gives the most optimal assay conditions to minimize variability and possible adverse effects. We showed that Cal520 had the smallest effect on hiPS-CMs together with the longest-lasting stable amplitude signal (up to 4 h). Although all dyes had a (minor) acute effect on hiPS-CMs, in the form of reduced beat rate and prolonged field potential duration, the selection of the dye did not influence the pharmacological response of four cardioactive drugs (dofetilide, moxifloxacin, nimodipine and isoprenaline). In conclusion, we have documented that different calcium sensitive dyes have only minor direct (acute) effects on hiPS-CMs with Cal520 showing the least effects and the longest lasting signal amplitude. Importantly, drug-induced pharmacological responses in hiPS-CMs were comparable between the three dyes. These findings should help further improve the robustness of the hiPS-CMs-based calcium transient assay as a predictive, preclinical cardiac safety evaluation tool. Copyright © 2018 Elsevier Inc. All rights reserved.

Self-organized porphyrin nanomaterials for solar energy harvesting

NASA Astrophysics Data System (ADS)

Radivojevic, Ivana

New concepts in the design and function of organic dyes as sensitizers for solar energy harvesting are needed. Commercial viability constrains these designs: (a) cost effective synthesis, (b) long-term stability, and (c) an important goal is to reduce the environmental impact of the product at the end of its life cycle. Simple porphyrinoid dyes meet these constraints, but new modes of incorporation into devices are needed to increase the efficiency of charge separation that drives any photonic device designed to harvest light. In this thesis, we will show how complex material architectures on surfaces need not to be the result of complex molecular structures or strong intermolecular forces that form in solution and deposit intact onto surfaces. Varying environmental conditions we can dictate morphology of self-organized structures on surfaces. These studies provide further insights into the design principles, processing, and extent of electron and energy transfer in supramolecular porphyrin materials. We are also developing a new strategy to couple porphyrinoid dyes to oxide surfaces using hafnium and zirconium metalloporphyrins and metallophthalocyanines.The mode of dye attachment to oxide surfaces is a key parameter for the construction of efficient dye sensitized solar cells. Porphyrinoid dyes containing oxophylic group (IV) metal ions that protrude from on face of the macrocycle allow connections directly to oxide surfaces, wherein the metal ion serves as the conduit. Since the charge transport efficiency is mediated by appropriate matching of molecular HOMO-LUMO gaps to semiconductor band gaps, we will show characterized solution phase ground and excited redox potentials of these dyes, and also photophysical properties of dye excited state using transient absorbance spectroscopy.

Cosensitization of D-A-π-A quinoxaline organic dye: efficiently filling the absorption valley with high photovoltaic efficiency.

PubMed

Pei, Kai; Wu, Yongzhen; Li, Hui; Geng, Zhiyuan; Tian, He; Zhu, Wei-Hong

2015-03-11

In the efficient cosensitization, the pure organic sensitizers with high molecular extinction coefficients and long wavelength response are highly preferable since the dye loading amount for each dye in cosensitization is decreased with respect to single dye sensitization. A D-A-π-A featured quinoxaline organic sensitizer IQ21 is specifically designed. The high conjugation building block of 4H-cyclopenta[2,1-b:3,4-b']dithiophene (CPDT) is introduced as the π bridge, instead of the traditional thiophene unit, especially in realizing high molecular extinction coefficients (up to 66 600 M(-1) cm(-1)) and extending the light response wavelength. With respect to the reference dye IQ4, the slightly lower efficiency of IQ21 (9.03%) arises from the decrease of VOC, which offsets the gain in JSC. While cosensitized with a smaller D-π-A dye S2, the efficiency in IQ21 is further improved to 10.41% (JSC = 19.8 mA cm(-2), VOC = 731 mV, FF = 0.72). The large improvement in efficiency is attributed to the well-matched molecular structures and loading amounts of both dyes in the cosensitization system. We also demonstrated that coabsorbent dye S2 can distinctly compensate the inherent drawbacks of IQ21, not only enhancing the response intensity of IPCE, making up the absorption defects around low wavelength region of IPCE, but also repressing the charge recombination rate to some extent.

Enhancement of the photoproperties of solid-state TiO2|dye|CuI cells by coupling of two dyes

NASA Astrophysics Data System (ADS)

Sirimanne, P. M.; Senevirathna, M. K. I.; Premalal, E. V. A.; Pitigala, P. K. D. D. P.

2006-06-01

The electronic coupling of a natural pigment extracted from pomegranate fruits (rich with cyanin and exist as flavylium at natural PH) with an organic dye mercurochrome enhanced the performance of solid-state TiO2|dye|CuI-type photovoltaic cells sensitized from pomegranate pigments or mercurochrome individually.

Effects of Taiwan Roselle anthocyanin treatment and single-walled carbon nanotube addition on the performance of dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Chou, C. S.; Tsai, P. J.; Wu, P.; Shu, G. G.; Huang, Y. H.; Chen, Y. S.

2014-04-01

This study investigates the relationship between the performance of a dye-sensitized solar cell (DSSC) sensitized by a natural sensitizer of Taiwan Roselle anthocyanin (TRA) and fabrication process conditions of the DSSC. A set of systematic experiments has been carried out at various soaking temperatures, soaking periods, sensitizer concentrations, pH values, and additions of single-walled carbon nanotube (SWCNT). An absorption peak (520 nm) is found for TRA, and it is close to that of the N719 dye (518 nm). At a fixed concentration of TRA and a fixed soaking period, a lower pH of the extract or a lower soaking temperature is found favorable to the formation of pigment cations, which leads to an enhanced power conversion efficiency (η) of DSSC. For instance, by applying 17.53 mg/100ml TRA at 30 for 10 h, as the pH of the extract decreases to 2.00 from 2.33 (the original pH of TRA), the η of DSSC with TiO2+SWCNT electrode increases to 0.67% from 0.11% of a traditional DSSC with TiO2 electrode. This performance improvement can be explained by the combined effect of the pH of sensitizer and the additions of SWCNT, a first investigation in DSSC using the natural sensitizer with SWCNT.

Label-free and sensitive fluorescence detection of nucleic acid, based on combination of a graphene oxid /SYBR green I dye platform and polymerase assisted signal amplification

NASA Astrophysics Data System (ADS)

Zhu, Xiao; Xing, Da

2012-12-01

A new label-free isothermal fluorescence amplification detection for nucleic acid has been developed. In this paper, we first developed a novel sensitive and specific detection platform with an unmodified hairpin probe (HP) combination of the graphene oxid (GO)/ SYBR green I dye (SG), which was relied on the selective principle of adsorption and the high quenching efficiency of GO. Then for the application of this new strategy, we used Mirco RNA-21 (Mir-21) as the target to evaluate this working principle of our design. When the target was hybridizing with the HP and inducing its conformation of change, an efficient isothermal circular strand-displacement polymerization reaction was activating to assist the first signal amplification. In this format, the formed complex conformation of DNA would interact with its high affinity dye, then detached from the surface of GO after incubating with the platform of GO/intercalating dye. This reaction would accompany with obvious fluorescence recovery, and accomplish farther signal enhancement by a mass of intercalating dye inserting into the minor groove of the long duplex replication product. By taking advantage of the multiple amplification of signal, this method exerted substantial enhancement in sensitivity and could be used for rapid and selective detection of Mir-21 with attomole range. It is expected that this cost-effective GO based sensor might hold considerable potential to apply in bioanalysis studies.

Feasibility of Using Fluorescence Spectrophotometry to Develop a Sensitive Dye Immersion Method for Container Closure Integrity Testing of Prefilled Syringes.

PubMed

Lu, Xujin; Lloyd, David K; Klohr, Steven E

2016-01-01

A feasibility study was conducted for a sensitive and robust dye immersion method for the measurement of container closure integrity of unopened prefilled syringes using fluorescence spectrophotometry as the detection method. A Varian Cary Eclipse spectrofluorometer was used with a custom-made sample holder to position the intact syringe in the sample compartment for fluorescence measurements. Methylene blue solution was initially evaluated as the fluorophore in a syringe with excitation at 607 nm and emission at 682 nm, which generated a limit of detection of 0.05 μg/mL. Further studies were conducted using rhodamine 123, a dye with stronger fluorescence. Using 480 nm excitation and 525 nm emission, the dye in the syringe could be easily detected at levels as low as 0.001 μg/mL. The relative standard deviation for 10 measurements of a sample of 0.005 μg/mL (with repositioning of the syringe after each measurement) was less than 1.1%. A number of operational parameters were optimized, including the photomultiplier tube voltage, excitation, and emission slit widths. The specificity of the testing was challenged by using marketed drug products and a protein sample, which showed no interference to the rhodamine detection. Results obtained from this study demonstrated that using rhodamine 123 for container closure integrity testing with in-situ (in-syringe) fluorescence measurements significantly enhanced the sensitivity and robustness of the testing and effectively overcame limitations of the traditional methylene blue method with visual or UV-visible absorption detection. Ensuring container closure integrity of injectable pharmaceutical products is necessary to maintain quality throughout the shelf life of a sterile drug product. Container closure integrity testing has routinely been used to evaluate closure integrity during product development and production line qualification of prefilled syringes, vials, and devices. However, container closure integrity testing has recently gained industry attention due to increased regulatory agency scrutiny regarding the analytical rigor of container closure integrity testing methods and expectations to use container closure integrity testing in lieu of sterility tests in stability programs. Methylene blue dye is often used for dye ingress testing of container closure integrity, but we found it unsuitable for reliable detection of small breaches in prefilled syringes of drug product. This work describes the suitability and advantages of using a fluorescent dye and spectroscopic detection for a robust, sensitive, and quality control-friendly container closure integrity testing method for prefilled syringes. © PDA, Inc. 2016.

Monitoring N3 dye adsorption and desorption on TiO2 surfaces: a combined QCM-D and XPS study.

PubMed

Wayment-Steele, Hannah K; Johnson, Lewis E; Tian, Fangyuan; Dixon, Matthew C; Benz, Lauren; Johal, Malkiat S

2014-06-25

Understanding the kinetics of dye adsorption and desorption on semiconductors is crucial for optimizing the performance of dye-sensitized solar cells (DSSCs). Quartz crystal microbalance with dissipation monitoring (QCM-D) measures adsorbed mass in real time, allowing determination of binding kinetics. In this work, we characterize adsorption of the common RuBipy dye N3 to the native oxide layer of a planar, sputter-coated titanium surface, simulating the TiO2 substrate of a DSSC. We report adsorption equilibrium constants consistent with prior optical measurements of N3 adsorption. Dye binding and surface integrity were also verified by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy (XPS). We further study desorption of the dye from the native oxide layer on the QCM sensors using tetrabutylammonium hydroxide (TBAOH), a commonly used industrial desorbant. We find that using TBAOH as a desorbant does not fully regenerate the surface, though little ruthenium or nitrogen is observed by XPS after desorption, suggesting that carboxyl moieties of N3 remain bound. We demonstrate the native oxide layer of a titanium sensor as a valid and readily available planar TiO2 morphology to study dye adsorption and desorption and begin to investigate the mechanism of dye desorption in DSSCs, a system that requires further study.

Wide-field in vivo neocortical calcium dye imaging using a convection-enhanced loading technique combined with simultaneous multiwavelength imaging of voltage-sensitive dyes and hemodynamic signals

PubMed Central

Ma, Hongtao; Harris, Samuel; Rahmani, Redi; Lacefield, Clay O.; Zhao, Mingrui; Daniel, Andy G. S.; Zhou, Zhiping; Bruno, Randy M.; Berwick, Jason; Schwartz, Theodore H.

2014-01-01

Abstract. In vivo calcium imaging is an incredibly powerful technique that provides simultaneous information on fast neuronal events, such as action potentials and subthreshold synaptic activity, as well as slower events that occur in the glia and surrounding neuropil. Bulk-loading methods that involve multiple injections can be used for single-cell as well as wide-field imaging studies. However, multiple injections result in inhomogeneous loading as well as multiple sites of potential cortical injury. We used convection-enhanced delivery to create smooth, continuous loading of a large area of the cortical surface through a solitary injection site and demonstrated the efficacy of the technique using confocal microscopy imaging of single cells and physiological responses to single-trial events of spontaneous activity, somatosensory-evoked potentials, and epileptiform events. Combinations of calcium imaging with voltage-sensitive dye and intrinsic signal imaging demonstrate the utility of this technique in neurovascular coupling investigations. Convection-enhanced loading of calcium dyes may be a useful technique to advance the study of cortical processing when widespread loading of a wide-field imaging is required. PMID:25525611

Wide-field in vivo neocortical calcium dye imaging using a convection-enhanced loading technique combined with simultaneous multiwavelength imaging of voltage-sensitive dyes and hemodynamic signals.

PubMed

Ma, Hongtao; Harris, Samuel; Rahmani, Redi; Lacefield, Clay O; Zhao, Mingrui; Daniel, Andy G S; Zhou, Zhiping; Bruno, Randy M; Berwick, Jason; Schwartz, Theodore H

2014-07-24

In vivo calcium imaging is an incredibly powerful technique that provides simultaneous information on fast neuronal events, such as action potentials and subthreshold synaptic activity, as well as slower events that occur in the glia and surrounding neuropil. Bulk-loading methods that involve multiple injections can be used for single-cell as well as wide-field imaging studies. However, multiple injections result in inhomogeneous loading as well as multiple sites of potential cortical injury. We used convection-enhanced delivery to create smooth, continuous loading of a large area of the cortical surface through a solitary injection site and demonstrated the efficacy of the technique using confocal microscopy imaging of single cells and physiological responses to single-trial events of spontaneous activity, somatosensory-evoked potentials, and epileptiform events. Combinations of calcium imaging with voltage-sensitive dye and intrinsic signal imaging demonstrate the utility of this technique in neurovascular coupling investigations. Convection-enhanced loading of calcium dyes may be a useful technique to advance the study of cortical processing when widespread loading of a wide-field imaging is required.

Function of CN group in organic sensitizers: The first principle study.

PubMed

Liu, Yun; Shao, Di; Bai, Xiaohui; Yang, Zhenqing; Lin, Chundan; Shao, Changjin

2017-05-15

The cyano group (CN) of the acceptor in organic sensitizers plays an important role for highly efficient dye-sensitized solar cells. In this paper, three 5, 6-difluoro-2,1,3-benzothiadiazole (DFBTD) organic molecules with different number of CN units, named ME15, ME16 and ME17, were investigated by the density functional theory (DFT) and time-dependent DFT (TDDFT). We analyzed the CNs effects on the electronic structures, optical properties, adsorption modes and electron transfer and injection. The result shows that ME17 has the largest maximum absorption wavelength (λ max ) among these new designed dyes due to the strong electron withdrawing ability of two CNs. In addition, CN greatly influence the adsorption modes of dye/TiO 2 and electron injection mechanism. ME16 with one CN also has good optical absorption properties and its acceptor has the strongest coupling strength with the TiO 2 semiconductor which is favorable for electron transfer and injection. Thus, we believe that the number of CN groups in acceptor should be moderate and one CN in D-A-π-A structure dyes may be the more appropriate focusing on the light harvesting ability, electron transfer and electron injection. Copyright © 2017 Elsevier B.V. All rights reserved.

Improving the efficiency of water splitting in dye-sensitized solar cells by using a biomimetic electron transfer mediator

PubMed Central

Zhao, Yixin; Swierk, John R.; Megiatto, Jackson D.; Sherman, Benjamin; Youngblood, W. Justin; Qin, Dongdong; Lentz, Deanna M.; Moore, Ana L.; Moore, Thomas A.; Gust, Devens; Mallouk, Thomas E.

2012-01-01

Photoelectrochemical water splitting directly converts solar energy to chemical energy stored in hydrogen, a high energy density fuel. Although water splitting using semiconductor photoelectrodes has been studied for more than 40 years, it has only recently been demonstrated using dye-sensitized electrodes. The quantum yield for water splitting in these dye-based systems has, so far, been very low because the charge recombination reaction is faster than the catalytic four-electron oxidation of water to oxygen. We show here that the quantum yield is more than doubled by incorporating an electron transfer mediator that is mimetic of the tyrosine-histidine mediator in Photosystem II. The mediator molecule is covalently bound to the water oxidation catalyst, a colloidal iridium oxide particle, and is coadsorbed onto a porous titanium dioxide electrode with a Ruthenium polypyridyl sensitizer. As in the natural photosynthetic system, this molecule mediates electron transfer between a relatively slow metal oxide catalyst that oxidizes water on the millisecond timescale and a dye molecule that is oxidized in a fast light-induced electron transfer reaction. The presence of the mediator molecule in the system results in photoelectrochemical water splitting with an internal quantum efficiency of approximately 2.3% using blue light. PMID:22547794

Charge Transfer Enhancement in the D-π-A Type Porphyrin Dyes: A Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) Study.

PubMed

Kang, Guo-Jun; Song, Chao; Ren, Xue-Feng

2016-11-25

The electronic geometries and optical properties of two D-π-A type zinc porphyrin dyes (NCH₃-YD2 and TPhe-YD) were systematically investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to reveal the origin of significantly altered charge transfer enhancement by changing the electron donor of the famous porphyrin-based sensitizer YD2-o-C8. The molecular geometries and photophysical properties of dyes before and after binding to the TiO₂ cluster were fully investigated. From the analyses of natural bond orbital (NBO), extended charge decomposition analysis (ECDA), and electron density variations (Δρ) between the excited state and ground state, it was found that the introduction of N(CH₃)₂ and 1,1,2-triphenylethene groups enhanced the intramolecular charge-transfer (ICT) character compared to YD2-o-C8. The absorption wavelength and transition possess character were significantly influenced by N(CH₃)₂ and 1,1,2-triphenylethene groups. NCH₃-YD2 with N(CH₃)₂ groups in the donor part is an effective way to improve the interactions between the dyes and TiO₂ surface, light having efficiency (LHE), and free energy change (ΔG inject ), which is expected to be an efficient dye for use in dye-sensitized solar cells (DSSCs).

New dye-sensitized solar cells obtained from extracted bracts of Bougainvillea glabra and spectabilis betalain pigments by different purification processes.

PubMed

Hernandez-Martinez, Angel Ramon; Estevez, Miriam; Vargas, Susana; Quintanilla, Fracisco; Rodriguez, Rogelio

2011-01-01

The performance of a new dye-sensitized solar cell (DSSC) based in a natural dye extracted from the Bougainvillea spectabilis' bracts, is reported. The performance of this solar cell was compared with cells prepared using extract of the Bougainvillea glabra and mixture of both extracts; in both cases the pigments were betalains, obtained from Reddish-purple extract. These dyes were purified to different extents and used for the construction of solar cells that were electrically characterized. The materials were characterized using FTIR and UV-Vis. Solar cells were assembled using TiO(2) thin film on indium tin oxide (ITO)-coated glass; a mesoporous film was sensitized with the Bougainvillea extracts. The obtained solar energy conversion efficiency was of 0.48% with a current density J(SC) of 2.29 mA/cm(2) using an irradiation of 100 mW/cm(2) at 25 °C.

Near Field Enhanced Photocurrent Generation in P-type Dye-Sensitized Solar Cells

PubMed Central

Xu, Xiaobao; Cui, Jin; Han, Junbo; Zhang, Junpei; Zhang, Yibo; Luan, Lin; Alemu, Getachew; Wang, Zhong; Shen, Yan; Xiong, Dehua; Chen, Wei; Wei, Zhanhua; Yang, Shihe; Hu, Bin; Cheng, Yibing; Wang, Mingkui

2014-01-01

Over the past few decades, the field of p-type dye-sensitized solar cell (p-DSSC) devices has undergone tremendous advances, in which Cu-based delafossite nanocrystal is of prime interest. This paper presents an augment of about 87% improvement in photocurrent observed in a particular configuration of organic dye P1 sensitized CuCrO2 delafossite nanocrystal electrode coupled with organic redox shuttle, 1-methy-1H- tetrazole-5-thiolate and its disulfide dimer when Au nanoparticles (NPs, with diameter of about 20 nm) is added into the photocathode, achieving a power convert efficiency of 0.31% (measured under standard AM 1.5 G test conditions). Detailed investigation shows that the local electrical-magnetic field effect, induced by Au NPs among the mesoporous CuCrO2 film, can improve the charge injection efficiency at dye/semiconductor interface, which is responsible for the bulk of the gain in photocurrent. PMID:24492539

Single-crystalline self-branched anatase titania nanowires for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Li, Zhenquan; Yang, Huang; Wu, Fei; Fu, Jianxun; Wang, Linjun; Yang, Weiguang

2017-03-01

The morphology of the anatase titania plays an important role in improving the photovoltaic performance in dye-sensitized solar cells. In this work, single-crystalline self-branched anatase TiO2 nanowires have been synthesized by hydrothermal method using TBAH and CTAB as morphology controlling agents. The obtained self-branched TiO2 nanowires dominated by a large percentage of (010) facets. The photovoltaic conversion efficiency (6.37%) of dye-sensitized solar cell (DSSC) based on the self-branched TiO2 nanowires shows a significant improvement (26.6%) compared to that of P25 TiO2 (5.03%). The enhanced performance of the self-branched TiO2 nanowires-based DSSC is due to heir large percent of exposed (010) facets which have strong dye adsorption capacity and effective charge transport of the self-branched 1D nanostructures.

Modulated charge injection in p-type dye-sensitized solar cells using fluorene-based light absorbers.

PubMed

Liu, Zonghao; Xiong, Dehua; Xu, Xiaobao; Arooj, Qudsia; Wang, Huan; Yin, Liyuan; Li, Wenhui; Wu, Huaizhi; Zhao, Zhixin; Chen, Wei; Wang, Mingkui; Wang, Feng; Cheng, Yi-Bing; He, Hongshan

2014-03-12

In this study, new pull-push arylamine-fluorene based organic dyes zzx-op1, zzx-op2, and zzx-op3 have been designed and synthesized for p-type dye-sensitized solar cells (p-DSCs). In zzx-op1, a di(p-carboxyphenyl)amine (DCPA) was used as an electron donor, a perylenemonoimide (PMID) as an electron acceptor, and a fluorene (FLU) unit with two aliphatic hexyl chains as a π-conjugated linker. In zzx-op2 and zzx-op3, a 3,4-ethylenedioxythiophene (EDOT) and a thiophene were inserted consecutively between PMID and FLU to tune the energy levels of the frontier molecular orbitals of the dyes. The structural modification broadened the spectral coverage from an onset of 700 nm for zzx-op1 to 750 nm for zzx-op3. The electron-rich EDOT and thiophene lifted up the HOMO (highest occupied molecular orbital) levels of zzx-op2 and zzx-op3, making their potential more negative than zzx-op1. When three dyes were employed in p-type DSCs with I(-)/I3(-) as a redox couple and NiO nanoparticles as hole materials, zzx-op1 exhibited impressive energy conversion efficiency of 0.184% with the open-circuit voltage (VOC) of 112 mV and the short-circuit current density (JSC) of 4.36 mA cm(-2) under AM 1.5G condition. Density functional theory calculations, transient photovoltage decay measurements, and electrochemical impedance spectroscopic studies revealed that zzx-op1 sensitized solar cell exhibited much higher charge injection efficiency (90.3%) than zzx-op2 (53.9%) and zzx-op3 (39.0%), indicating a trade-off between spectral broadening and electron injection driving force in p-type DSCs.

Self-Assembly of Cis-Configured Squaraine Dyes at the TiO2-Dye Interface: Far-Red Active Dyes for Dye-Sensitized Solar Cells.

PubMed

Punitharasu, Vellimalai; Mele Kavungathodi, Munavvar Fairoos; Nithyanandhan, Jayaraj

2018-05-16

To synergize both steric and electronic factors in designing the dyes for dye-sensitized solar cells, a series of cis-configured unsymmetrical squaraine dyes P11-P15 with suitably functionalized alkyl groups and squaric acid units containing the electron-withdrawing groups were synthesized, respectively. These dyes capture the importance of (i) the effect and position of branched alkyl groups, (ii) mono- and di-anchoring groups containing dyes, and (iii) further appending the alkyl groups through the cyanoester vinyl unit on the central squaric acid units of D-A-D-based cis-configured squaraine dyes. All the above factors govern the controlled self-assembly of the dyes on the TiO 2 surface which helps to broaden the absorption profile of the dyes with an increased energy-harvesting process. With respect to the position of the branched alkyl groups, dye P11 with the sp 3 -C and N-alkyl groups away from the TiO 2 surface showed a better device efficiency of 5.98% ( J sc of 14.46 mA cm -2 , V oc of 0.576 V, and ff of 71.8%) than its positional isomer P12 with 3.45% ( J sc of 8.78 mA cm -2 , V oc of 0.554 V, and ff of 70.9%). However, with respect to the dyes containing mono- and di-anchoring groups, P13 with two anchoring units exhibited a superior device performance of 7.58% ( J sc of 17.12 mA cm -2 , V oc of 0.618 V, and ff of 71.7%) in the presence of optically transparent co-adsorbent CDCA (3α,7α-dihydroxy-5β-cholanic acid) than dyes P11 and P12.

A dye-sensitized photoelectrochemical tandem cell for light driven hydrogen production from water

DOE PAGES

Sherman, Benjamin D.; Sheridan, Matthew V.; Wee, Kyung -Ryang; ...

2016-12-02

Here, tandem junction photoelectrochemical water-splitting devices, whereby two light absorbing electrodes targeting separate portions of the solar spectrum generate the voltage required to convert water to oxygen and hydrogen, enable much higher possible efficiencies than single absorber systems. We report here on the development of a tandem system consisting of a dye-sensitized photoelectrochemical cell (DSPEC) wired in series with a dye-sensitized solar cell (DSC). The DSPEC photoanode incorporates a tris(bipyridine)ruthenium(II)-type chromophore and molecular ruthenium based water oxidation catalyst. The DSPEC was tested with two more-red absorbing DSC variations, one utilizing N719 dye with an I 3 –/I – redox mediatormore » solution and the other D35 dye with a tris(bipyridine)cobalt ([Co(bpy) 3] 3+/2+) based mediator. The tandem configuration consisting of the DSPEC and D35/[Co(bpy) 3] 3+/2+ based DSC gave the best overall performance and demonstrated the production of H 2 from H 2O with the only energy input from simulated solar illumination.« less

Electric field assisted sintering to improve the performance of nanostructured dye sensitized solar cell (DSSC)

NASA Astrophysics Data System (ADS)

Shojaeifar, Mohsen; Mohajerani, Ezeddin; Fathollahi, Mohammadreza

2018-01-01

Herein, we report the application of electric field assisted sintering (EFAS) procedure in dye sensitized solar cells (DSSCs). The EFAS process improved DSSC performance by enhancing optical and electrical characteristics simultaneously. The EFAS procedure is shown to be capable of reducing the TiO2 nanoparticle aggregation leading to the higher surface area for dye molecules adsorbates. Lower nanoparticle aggregation can be evidently observed by field emission scanning electron microscopy imaging. By applying an external electric field, the current density and conversion efficiency improved significantly about 30% and 45%, respectively. UV-Visible spectra of the desorbed dye molecules on the porous nanoparticles bedding confirm a higher amount of dye loading in the presence of an external electric field. Correspondingly, comprehensive J-V characteristics modeling reveals the enhancement of the diffusion coefficient by EFAS process. The proposed method can be applied to improve the efficiency of the mesostructured hybrid perovskite solar cells, photodetectors, and quantum dot-sensitized solar cells, as well as reduction of the surface area loss in all porous media.

Molecular lemmings: strategies to avoid when designing BODIPY ferrocene dyads for dye-sensitized solar cell applications.

PubMed

Hussein, B A; Huynh, J T; Prieto, P L; Barran, C P; Arnold, A E; Sarycheva, O V; Lough, A J; Koivisto, B D

2018-04-03

BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes) dyes possess intense absorption profiles that can be exploited in various light harvesting applications. However, redox stability and optimization of frontier molecular orbital energies in these dyes are critical for their successful incorporation into new solar cell materials. This article describes the synthesis and characterization of a family of β-substituted BODIPY-ferrocene dyads with push-pull architectures. Designed to stabilize the photo-oxidized BODIPY for dye-sensitized solar cell (DSSC) applications, some deleterious electron transfer behaviours emerged when the ferrocene unit was conjugated to electron deficient BODIPYs. These findings are discussed herein.

Control of interfacial charge-transfer interaction of dye and p-CuI in solid-state dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Moribe, Shinya; Kato, Naohiko; Higuchi, Kazuo; Mizumoto, Katsuyoshi; Toyoda, Tatsuo

2017-04-01

We systematically investigated the photovoltaic and absorption characteristics of solid-state dye-sensitized solar cells with CuI to elucidate the impact of the interaction between the dye and CuI. For the ruthenium complex N719, the incident photon-to-current conversion efficiency (IPCE) on the longer-wavelength side decreased owing to the change of the metal-to-ligand charge transfer (CT) of N719 due to the interaction between the thiocyanate groups of N719 and CuI. In contrast, when D149 — which included rhodanine groups — was used, the interaction with CuI and the resultant CT increased the IPCE. The results provide a new strategy for improving the photovoltaic performance by controlling the interfacial CT between the dye and CuI.

Experimenting with cameraless photography using turmeric and borax: an introduction to photophysics

NASA Astrophysics Data System (ADS)

Appleyard, S. J.

2012-07-01

An alcoholic extract of the spice turmeric can be used to create a light-sensitive dye that can be used to stain paper. On exposure to sunlight, the dyed paper can be used to capture photographic images of flat objects or reproduce existing images through the preferential degradation of the dye in light-exposed areas over a time period of a few hours. The images can be developed and preserved by spraying the exposed paper with a dilute solution of borax, which forms coloured organo-boron complexes that limit further degradation of the dye and enhance the colour of the image. Similar photochemical reactions that lead to the degradation of the turmeric dye can also be used for reducing the organic pollution load in wastewater produced by many industrial processes and in dye-sensitized solar cells for producing electricity.

Dye adsorption mechanisms in TiO2 films, and their effects on the photodynamic and photovoltaic properties in dye-sensitized solar cells.

PubMed

Hwang, Kyung-Jun; Shim, Wang-Geun; Kim, Youngjin; Kim, Gunwoo; Choi, Chulmin; Kang, Sang Ook; Cho, Dae Won

2015-09-14

The adsorption mechanism for the N719 dye on a TiO2 electrode was examined by the kinetic and diffusion models (pseudo-first order, pseudo-second order, and intra-particle diffusion models). Among these methods, the observed adsorption kinetics are well-described using the pseudo-second order model. Moreover, the film diffusion process was the main controlling step of adsorption, which was analysed using a diffusion-based model. The photodynamic properties in dye-sensitized solar cells (DSSCs) were investigated using time-resolved transient absorption techniques. The photodynamics of the oxidized N719 species were shown to be dependent on the adsorption time, and also the adsorbed concentration of N719. The photovoltaic parameters (Jsc, Voc, FF and η) of this DSSC were determined in terms of the dye adsorption amounts. The solar cell performance correlates significantly with charge recombination and dye regeneration dynamics, which are also affected by the dye adsorption amounts. Therefore, the photovoltaic performance of this DSSC can be interpreted in terms of the adsorption kinetics and the photodynamics of oxidized N719.

Hyperbranched quasi-1D nanostructures for solid-state dye-sensitized solar cells.

PubMed

Passoni, Luca; Ghods, Farbod; Docampo, Pablo; Abrusci, Agnese; Martí-Rujas, Javier; Ghidelli, Matteo; Divitini, Giorgio; Ducati, Caterina; Binda, Maddalena; Guarnera, Simone; Li Bassi, Andrea; Casari, Carlo Spartaco; Snaith, Henry J; Petrozza, Annamaria; Di Fonzo, Fabio

2013-11-26

In this work we demonstrate hyperbranched nanostructures, grown by pulsed laser deposition, composed of one-dimensional anatase single crystals assembled in arrays of high aspect ratio hierarchical mesostructures. The proposed growth mechanism relies on a two-step process: self-assembly from the gas phase of amorphous TiO2 clusters in a forest of tree-shaped hierarchical mesostructures with high aspect ratio; oriented crystallization of the branches upon thermal treatment. Structural and morphological characteristics can be optimized to achieve both high specific surface area for optimal dye uptake and broadband light scattering thanks to the microscopic feature size. Solid-state dye sensitized solar cells fabricated with arrays of hyperbranched TiO2 nanostructures on FTO-glass sensitized with D102 dye showed a significant 66% increase in efficiency with respect to a reference mesoporous photoanode and reached a maximum efficiency of 3.96% (among the highest reported for this system). This result was achieved mainly thanks to an increase in photogenerated current directly resulting from improved light harvesting efficiency of the hierarchical photoanode. The proposed photoanode overcomes typical limitations of 1D TiO2 nanostructures applied to ss-DSC and emerges as a promising foundation for next-generation high-efficiency solid-state devices comprosed of dyes, polymers, or quantum dots as sensitizers.

Dye-controlled interfacial electron transfer for high-current indium tin oxide photocathodes.

PubMed

Huang, Zhongjie; He, Mingfu; Yu, Mingzhe; Click, Kevin; Beauchamp, Damian; Wu, Yiying

2015-06-01

Efficient sensitized photocathodes are highly desired for solar fuels and tandem solar cells, yet the development is hindered by the scarcity of suitable p-type semiconductors. The generation of high cathodic photocurrents by sensitizing a degenerate n-type semiconductor (tin-doped indium oxide; ITO) is reported. The sensitized mesoporous ITO electrodes deliver cathodic photocurrents of up to 5.96±0.19 mA cm(-2), which are close to the highest record in conventional p-type sensitized photocathodes. This is realized by the rational selection of dyes with appropriate energy alignments with ITO. The energy level alignment between the highest occupied molecular orbital of the sensitizer and the conduction band of ITO is crucial for efficient hole injection. Transient absorption spectroscopy studies demonstrate that the cathodic photocurrent results from reduction of the photoexcited sensitizer by free electrons in ITO. Our results reveal a new perspective toward the selection of electrode materials for sensitized photocathodes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

3D graphene from CO 2 and K as an excellent counter electrode for dye-sensitized solar cells

DOE PAGES

Wei, Wei; Stacchiola, Dario J.; Hu, Yun Hang

2017-07-19

3D graphene, which was synthesized directly from CO 2 via its exothermic reaction with liquid K, exhibited excellent performance as a counter electrode for a dye-sensitized solar cell (DSSC). The DSSC has achieved a high power conversion efficiency of 8.25%, which is 10 times larger than that (0.74%) of a DSSC with a counter electrode of the regular graphene synthesized via chemical exfoliation of graphite. The efficiency is even higher than that (7.73%) of a dye-sensitized solar cell with an expensive standard Pt counter electrode. This work provides a novel approach to use a greenhouse gas for DSSCs.

Counterion dye staining of proteins in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tryptic gel digestion of stained protein for mass spectrometry.

PubMed

Cong, Wei-Tao; Wang, Xu; Hwang, Sun-Young; Jin, Li-Tai; Choi, Jung-Kap

2012-01-01

A fast and matrix-assisted laser desorption/ionization mass spectrometry compatible protein staining method in one- and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis is described. It is based on the counterion dye staining method that employs oppositely charged two dyes, zincon and ethyl violet, to form an ion-pair complex. The protocol, including fixing, staining, and quick washing steps, can be completed in 1-1.5 h, depending upon gel thickness. It has the sensitivity comparable to the colloidal Coomassie Brilliant Blue G stain using phosphoric acid as a component of staining solution (4-8 ng). The counterion dye stain does not induce protein modifications that complicate interpretation of peptide mapping data from mass spectrometry. Considering the speed, sensitivity, and compatibility with mass spectrometry, the counterion dye stain may be more practical than any other dye-based protein stains for routine proteomic researches.

Photoactive layer based on T-shaped benzimidazole dyes used for solar cell: from photoelectric properties to molecular design

NASA Astrophysics Data System (ADS)

Xu, Beibei; Li, Yuanzuo; Song, Peng; Ma, Fengcai; Sun, Mengtao

2017-03-01

Three benzimidazole-based organic dyes, possessing the same triphenylamine donors and cyanoacrylic acid acceptors with the bithiophene π-bridges combined in different nuclear positions of benzimidazole, were investigated in the utility of dye-sensitizer solar cells. The structure, molecular orbital and energy, absorption spectra and some important parameters (such as light harvesting efficiency (LHE), electron injection driving force, the electron injection time, chemical reactivity parameters, vertical dipole moment as well as interaction models of dye-I2) were obtained according to Newns-Anderson model and DFT calculation. The process and strength of charge transfer and separation were visualized with charge different density and index of spatial extent (S, D and Δq). Current work paid attention to the new T-shaped dyes to reveal the relation between the structure and photoelectric performance. Furthermore, nine dyes (substitution of alkyl chains and π-bridges) have been designed and characterized to screen promising sensitizer candidates with excellent photo-electronic properties.

Novel benzanthrone probes for membrane and protein studies

NASA Astrophysics Data System (ADS)

Ryzhova, Olga; Vus, Kateryna; Trusova, Valeriya; Kirilova, Elena; Kirilov, Georgiy; Gorbenko, Galyna; Kinnunen, Paavo

2016-09-01

The applicability of a series of novel benzanthrone dyes to monitoring the changes in physicochemical properties of lipid bilayer and to differentiating between the native and aggregated protein states has been evaluated. Based on the quantitative parameters of the dye-membrane and dye-protein binding derived from the fluorimetric titration data, the most prospective membrane probes and amyloid tracers have been selected from the group of examined compounds. Analysis of the red edge excitation shifts of the membrane- and amyloid-bound dyes provided information on the properties of benzanthrone binding sites within the lipid and protein matrixes. To understand how amyloid specificity of benzanthrones correlates with their structure, quantitative structure activity relationship (QSAR) analysis was performed involving a range of quantum chemical molecular descriptors. A statistically significant model was obtained for predicting the sensitivity of novel benzanthrone dyes to amyloid fibrils.

TiO 2 -Assisted Photoisomerization of Azo Dyes Using Self-Assembled Monolayers: Case Study on para -Methyl Red Towards Solar-Cell Applications

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

Zhang, Lei; Cole, Jacqueline M.

2014-02-18

The optical and electronic properties of a TiO2 nanoparticle-assisted photo-isomerizable surface, prepared by an azo dye/TiO2 nanocomposite film, are examined experimentally and computationally. The azo dye, para-methyl red, undergoes photoisomerization at room temperature, catalyzed by the TiO2 nanoparticle supports, while it exhibits negligible photoisomerization in solvents under otherwise identical conditions. Density functional theory and time-dependent density functional theory are employed to explain the origin of this photoisomerization in these dye…TiO2 nanoparticle self-assembled monolayers (SAMs). The device performance of these SAMs when embedded into dye-sensitized solar cells is used to further elucidate the nature of this azo dye photoisomerization and relatemore » it to the ensuing optoelectronic properties.« less

Supersensitization of CdS quantum dots with a near-infrared organic dye: toward the design of panchromatic hybrid-sensitized solar cells.

PubMed

Choi, Hyunbong; Nicolaescu, Roxana; Paek, Sanghyun; Ko, Jaejung; Kamat, Prashant V

2011-11-22

The photoresponse of quantum dot solar cells (QDSCs) has been successfully extended to the near-IR (NIR) region by sensitizing nanostructured TiO(2)-CdS films with a squaraine dye (JK-216). CdS nanoparticles anchored on mesoscopic TiO(2) films obtained by successive ionic layer adsorption and reaction (SILAR) exhibit limited absorption below 500 nm with a net power conversion efficiency of ~1% when employed as a photoanode in QDSC. By depositing a thin barrier layer of Al(2)O(3), the TiO(2)-CdS films were further modified with a NIR absorbing squaraine dye. Quantum dot sensitized solar cells supersensitized with a squariand dye (JK-216) showed good stability during illumination with standard global AM 1.5 solar conditions, delivering a maximum overall power conversion efficiency (η) of 3.14%. Transient absorption and pulse radiolysis measurements provide further insight into the excited state interactions of squaraine dye with SiO(2), TiO(2), and TiO(2)/CdS/Al(2)O(3) films and interfacial electron transfer processes. The synergy of combining semiconductor quantum dots and NIR absorbing dye provides new opportunities to harvest photons from different regions of the solar spectrum. © 2011 American Chemical Society

Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

NASA Astrophysics Data System (ADS)

Sun, Zhijuan; Cai, Chenxin; Guo, Fei; Ye, Changhuai; Luo, Yingwu; Ye, Shuming; Luo, Jianchao; Zhu, Fan; Jiang, Chunyue

2018-04-01

Immobilization of the oxygen-sensitive probes (OSPs) in the host matrix greatly impacts the performance and long-term usage of the optical dissolved oxygen (DO) sensors. In this work, fluorescent dyes, as the OSPs, were encapsulated with a crosslinked fluorinated polymer shell by interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization to fabricate oxygen sensitive polymeric nanocapsules (NCs). The location of fluorescent dyes and the fluorescent properties of the NCs were fully characterized by fourier transform infrared spectrometer, x-ray photoelectron spectrometer and fluorescent spectrum. Dye-encapsulated capacity can be precisely tuned from 0 to 1.3 wt% without self-quenching of the fluorescent dye. The crosslinked fluorinated polymer shell is not only extremely high gas permeability, but also prevents the fluorescent dyes from leakage in aqueous as well as in various organic solvents, such as ethanol, acetone and tetrahydrofuran (THF). An optical DO sensor based on the oxygen sensitive NCs was fabricated, showing high sensitivity, short response time, full reversibility, and long-term operational stability of online monitoring DO. The sensitivity of the optical DO sensor is 7.02 (the ratio of the response value in fully deoxygenated and saturated oxygenated water) in the range 0.96-14.16 mg l-1 and the response time is about 14.3 s. The sensor’s work curve was fit well using the modified Stern-Volmer equation by two-site model, and its response values are hardly affected by pH ranging from 2 to 12 and keep constant during continuous measurement for 3 months. It is believed that the oxygen sensitive polymeric NCs-based optical DO sensor could be particularly useful in long-term online DO monitoring in both aqueous and organic solvent systems.

Photovoltaic characteristics of natural light harvesting dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Hafez, H. S.; Shenouda, S. S.; Fadel, M.

2018-03-01

In this work of research, anthocyanin as a natural dye obtained from raspberry fruits, was used and tested as a photon harvesting/electron donating dye in titanium dioxide nanoparticle-based DSSCs. A working photoelectrode made from TiO2 nanoparticles with an average particle size (10-40 nm) that is coated on Florine doped tin-oxide substrate, was prepared via a simple and low cost hydrothermal method. A detailed structural and morphological analysis of the TiO2 photoactive electrode was investigated by X-ray diffraction (XRD), diffuse reflectance spectrometer, transmission electron microscope (TEM) and scanning electron microscope (SEM). Complete photovoltaic characteristics including (current, voltage, outpower, and responsivity) of the natural anthocyanin based dye sensitized solar cell have been investigated under different illumination intensity ranging from 10 to 100 mW.cm- 2. The cell responsivity and efficiency of the fabricated solar cell under different illumination intensity were found to be in the range (R = 15.6-23.8 mA.W- 1 and η = 0.13-0.25) at AM = 1.5 conditions. This study is important for enhancing the future applications of the promising DSSC technology.

Cellulose nanocrystals (CNC) as carriers for a spirooxazine dye and its effect on photochromic efficiency.

PubMed

Sun, Bo; Hou, Qingxi; He, Zhibin; Liu, Zehua; Ni, Yonghao

2014-10-13

Nanocrystalline cellulose (CNC) as a renewable/sustainable material, has received much attention. Herein we studied CNC as carriers for a hydrophobic spirooxazine (SO)-based dye, 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphtha[2,1-b][1,4]oxazine], which may have potential applications in reversible memory photo-devices, textiles, photo-sensitive paper coatings, and inkjet printing inks. Due to the high cost and water-insolubility of this dye, it is desirable to improve its coloration efficiency and water-dispersibility. The experimental approach was to use CNC as carriers for the SO dye, thus obtaining a stable photochromic dye in aqueous systems. Transmission electron microscope (TEM) observation confirmed that the SO dye adsorbed on the surface of the CNC, which functioned as carriers for the photochromic dye. An impregnation process was adopted to anchor the dye onto cellulosic paper. It was found that the use of CNC resulted in a significant improvement in the SO coloration efficiency. The color stability and fatigue resistance were also studied. The use of CNC as carriers for a hydrophobic compound, its enhancement of associated properties, and its subsequent application were demonstrated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of TiO₂ and ZnO solar cells sensitized with an indoline dye: time-resolved laser spectroscopy studies of partial charge separation processes.

PubMed

Sobuś, Jan; Burdziński, Gotard; Karolczak, Jerzy; Idígoras, Jesús; Anta, Juan A; Ziółek, Marcin

2014-03-11

Time-resolved laser spectroscopy techniques in the time range from femtoseconds to seconds were applied to investigate the charge separation processes in complete dye-sensitized solar cells (DSC) made with iodide/iodine liquid electrolyte and indoline dye D149 interacting with TiO2 or ZnO nanoparticles. The aim of the studies was to explain the differences in the photocurrents of the cells (3-4 times higher for TiO2 than for ZnO ones). Electrochemical impedance spectroscopy and nanosecond flash photolysis studies revealed that the better performance of TiO2 samples is not due to the charge collection and dye regeneration processes. Femtosecond transient absorption results indicated that after first 100 ps the number of photoinduced electrons in the semiconductor is 3 times higher for TiO2 than for ZnO solar cells. Picosecond emission studies showed that the lifetime of the D149 excited state is about 3 times longer for ZnO than for TiO2 samples. Therefore, the results indicate that lower performance of ZnO solar cells is likely due to slower electron injection. The studies show how to correlate the laser spectroscopy methodology with global parameters of the solar cells and should help in better understanding of the behavior of alternative materials for porous electrodes for DSC and related devices.

Improvements in opti-chromic dosimeters for radiation processing

NASA Astrophysics Data System (ADS)

Humpherys, K. C.; Kantz, A. D.

"Opti-Chromic" dosimeters consisting of radiachromic dye in flourinated polymer tubing have been introduced as a dosimetry system in the range from 10 1 to 5 × 10 4 Gy. Batches of "Opti-Chromic" dosimeters have been produced to evaluate performance under large scale industrial conditions. A systematic study was undertaken to determine the effect of various dosimeter parameters on radiation sensitivity, shelf life, and response characteristics at the higher absorbed doses. These parameters were (A) Type of flourinated polymer tubing; (B) Organic solvent used to activate the radiachromic dye; (C) Concentration of radiachromic dye; (D) Additives to provide proper viscosity, color stability, and high-dose response. Prototype batches were produced and experimental dosimeters exposed to a range of absorbed doses and the response measured as a function of shelf life and dose. The results of the study are presented, and an improved formulation recommended for application to Food Processing. Other formulations may be of value in specific requirements of sensitivity or temperature.

An aqueous, organic dye derivatized SnO 2 /TiO 2 core/shell photoanode

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

Wee, Kyung-Ryang; Sherman, Benjamin D.; Brennaman, M. Kyle

2016-01-01

Visible light driven water splitting in a dye-sensitized photoelectrochemical cell (DSPEC) based on a phosphonic acid-derivatized donor–π–acceptor (D–π–A) organic dye (P–A–π–D) is described with the dye anchored to an FTO|SnO 2/TiO 2core/shell photoanode in a pH 7 phosphate buffer solution.

Photoswitchable non-fluorescent thermochromic dye-nanoparticle hybrid probes.

PubMed

Harrington, Walter N; Haji, Mwafaq R; Galanzha, Ekaterina I; Nedosekin, Dmitry A; Nima, Zeid A; Watanabe, Fumiya; Ghosh, Anindya; Biris, Alexandru S; Zharov, Vladimir P

2016-11-08

Photoswitchable fluorescent proteins with controllable light-dark states and spectral shifts in emission in response to light have led to breakthroughs in the study of cell biology. Nevertheless, conventional photoswitching is not applicable for weakly fluorescent proteins and requires UV light with low depth penetration in bio-tissue. Here we introduce a novel concept of photoswitchable hybrid probes consisting of thermochromic dye and absorbing nanoparticles, in which temperature-sensitive light-dark states and spectral shifts in absorption can be switched through controllable photothermal heating of doped nanoparticles. The proof-of-concept is demonstrated through the use of two different types of temperature-sensitive dyes doped with magnetic nanoparticles and reversibly photoswitched by a near-infrared laser. Photoacoustic imaging revealed the high contrast of these probes, which is sufficient for their visualization in cells and deep tissue. Our results suggest that these new photoswitchable multicolour probes can be used for multimodal cellular diagnostics and potentially for magnetic and photothermal therapy.

Photoswitchable non-fluorescent thermochromic dye-nanoparticle hybrid probes

NASA Astrophysics Data System (ADS)

Harrington, Walter N.; Haji, Mwafaq R.; Galanzha, Ekaterina I.; Nedosekin, Dmitry A.; Nima, Zeid A.; Watanabe, Fumiya; Ghosh, Anindya; Biris, Alexandru S.; Zharov, Vladimir P.

2016-11-01

Photoswitchable fluorescent proteins with controllable light-dark states and spectral shifts in emission in response to light have led to breakthroughs in the study of cell biology. Nevertheless, conventional photoswitching is not applicable for weakly fluorescent proteins and requires UV light with low depth penetration in bio-tissue. Here we introduce a novel concept of photoswitchable hybrid probes consisting of thermochromic dye and absorbing nanoparticles, in which temperature-sensitive light-dark states and spectral shifts in absorption can be switched through controllable photothermal heating of doped nanoparticles. The proof-of-concept is demonstrated through the use of two different types of temperature-sensitive dyes doped with magnetic nanoparticles and reversibly photoswitched by a near-infrared laser. Photoacoustic imaging revealed the high contrast of these probes, which is sufficient for their visualization in cells and deep tissue. Our results suggest that these new photoswitchable multicolour probes can be used for multimodal cellular diagnostics and potentially for magnetic and photothermal therapy.

Synthesis and characterization of UV-treated Fe-doped bismuth lanthanum titanate-doped TiO2 layers in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Song, Myoung Geun; Bark, Chung Wung

2016-06-01

Dye-sensitized solar cells (DSSCs) based on titanium dioxide (TiO2) have been extensively studied because they constitute promising low-cost alternatives to their conventional semiconductor-based counterparts. However, much of the effort aimed at achieving high conversion efficiencies has focused on dye and liquid electrolytes. In this work, we report the photovoltaic characteristics of DSSCs fabricated by mixing TiO2 with Fe-doped bismuth lanthanum titanate (Fe-BLT). These nanosized Fe-BLT powders were prepared by using a high-energy ball-milling process. In addition, we used a UV radiation-ozone (UV-O3) treatment to change the surface wettability of TiO2 from hydrophobic to hydrophilic and thereby prevented the easy separation of the Fe-BLT-mixed TiO2 from the fluorine-doped tin-oxide (FTO) coating glass.

Dermatotoxicologic clinical solutions: hair dying in hair dye allergic patients?

PubMed

Edwards, Ashley; Coman, Garrett; Blickenstaff, Nicholas; Maibach, Howard

2015-03-01

This article describes how to identify allergic contact dermatitis resulting from hair dye, and outlines interventions and prevention principles for those who wish to continue dyeing their hair despite being allergic. Hair dye chemicals thought to be the most frequent sensitizers are discussed with instructions for health care providers on how to counsel patients about techniques to minimize exposure to allergenic substances. This framework should allow many patients to continue dyeing their hair without experiencing adverse side effects.

Two-photon sensitized recording materials for multilayer optical disk

NASA Astrophysics Data System (ADS)

Akiba, M.; Goto-Takahashi, E.; Takizawa, H.; Sasaki, T.; Mochizuki, H.; Mikami, T.; Kitahara, T.

2010-06-01

Two types of novel two-photon sensitized recording material writable at 405 nm and 522nm were developed. The fluorescent dye generation type (F-type) material consists of at least two-photon absorption dye (TPAD) and fluorescent dye precursor (FDP), which is non-fluorescent before two-photon recording and fluorescent after two-photon recording due to fluorescent dye generation. The fluorescence quench type (Q-type) material, on the other hand, consists of at least TPAD, fluorescent dye (FD) and fluorescent quencher precursor (QP), which is fluorescent before two-photon recording and the fluorescence intensity is reduced after two-photon recording at the recorded spot due to fluorescent quencher generation. Both types of material showed quadratic dependency of recording light intensity at 522 and 405 nm. A twenty-layer two-photon recording media was fabricated with the Q-type material, and two-photon recording and onephoton fluorescent signal readout was successfully conducted.

Peripheral Hole Acceptor Moieties on an Organic Dye Improve Dye‐Sensitized Solar Cell Performance

PubMed Central

Hao, Yan; Gabrielsson, Erik; Lohse, Peter William; Yang, Wenxing; Johansson, Erik M. J.; Hagfeldt, Anders

2015-01-01

Investigation of charge transfer dynamics in dye‐sensitized solar cells is of fundamental interest and the control of these dynamics is a key factor for developing more efficient solar cell devices. One possibility for attenuating losses through recombination between injected electrons and oxidized dye molecules is to move the positive charge further away from the metal oxide surface. For this purpose, a metal‐free dye named E6 is developed, in which the chromophore core is tethered to two external triphenylamine (TPA) units. After photoinduced electron injection into TiO2, the remaining hole is rapidly transferred to a peripheral TPA unit. Electron–hole recombination is slowed down by 30% compared to a reference dye without peripheral TPA units. Furthermore, it is found that the added TPA moieties improve the electron blocking effect of the dye, retarding recombination of electrons from TiO2 to the cobalt‐based electrolyte. PMID:27722076

Near infrared harvesting dye-sensitized solar cells enabled by rare-earth upconversion materials.

PubMed

Li, Deyang; Ågren, Hans; Chen, Guanying

2018-02-01

Dye-sensitized solar cells (DSSCs) have been deemed as promising alternatives to silicon solar cells for the conversion of clean sunlight energy into electricity. A major limitation to their conversion efficiency is their inability to utilize light in the infrared (IR) spectral range, which constitutes almost half the energy of the sun's radiation. This fact has elicited motivations and endeavors to extend the response wavelength of DSSCs to the IR range. Photon upconversion through rare-earth ions constitutes one of the most promising approaches toward the goal of converting near-IR (NIR) or IR light into visible or ultraviolet light, where DSSCs typically have high sensitivity. In the present review, we summarize recent progress based on the utilization of various upconversion materials and device structures to improve the performance of dye-sensitized solar cells.

Sensitizing of TiO2 with a merocyanine dye in the photocatalytic reduction of methylene blue

NASA Astrophysics Data System (ADS)

Kobasa, I. M.; Kondratyeva, I. V.; Kropelnytska, Yu. V.

Three merocyanine dyes (D) with various polymethine chain lengths were checked for their applicability as sensitizers for TiO2. Based on the absorption data and cyclic voltammetric redox potentials, the lower unoccupied molecular orbital (LUMO) energy was calculated. The LUMO energy was higher than the conductance band edge energy of the anatase-type TiO2 for all the dyes, meaning that they all can act as efficient sensitizers for various functional materials to be used in the wide-zone visible light solar cells, toxic wastes decontamination technologies and other similar applications. Merocyanines applicability as effective sensitizing agents was approved by construction of the heterostructures (HS) D/TiO2 consisting of the merocyanines and acting as photocatalysts in the test reaction of methylene blue (MB) reduction by formaldehyde.

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

Goebel, Carsten, E-mail: goebel.c.1@pg.com; Troutman, John; Hennen, Jenny

The strong sensitizing potencies of the most important primary intermediates of oxidative hair dyes, p-phenylenediamine (PPD) and p-toluylenediamine (PTD, i.e. 2-methyl-PPD) are well established. They are considered as the key sensitizers in hair dye allergic contact dermatitis. While modification of their molecular structure is expected to alter their sensitizing properties, it may also impair their color performance. With introduction of a methoxymethyl side chain we found the primary intermediate 2-methoxymethyl-p-phenylenediamine (ME-PPD) with excellent hair coloring performance but significantly reduced sensitizing properties compared to PPD and PTD: In vitro, ME-PPD showed an attenuated innate immune response when analyzed for its proteinmore » reactivity and dendritic cell activation potential. In vivo, the effective concentration of ME-PPD necessary to induce an immune response 3-fold above vehicle control (EC3 value) in the local lymph node assay (LLNA) was 4.3%, indicating a moderate skin sensitizing potency compared to values of 0.1 and 0.17% for PPD and PTD, respectively. Finally, assessing the skin sensitizing potency of ME-PPD under consumer hair dye usage conditions through a quantitative risk assessment (QRA) indicated an allergy induction risk negligible compared to PPD or PTD. - Highlights: • Methoxymethyl side chain in p-phenylenediamine reduces its strong skin sensitizing properties. • Reduced protein reactivity and dendritic cell activation. • Reduced skin sensitizing potency in local lymph node assay (LLNA). • Negligible allergy induction risk under hair dye usage conditions.« less

Enhancement of electrical and optical performance of N719 by co-sensitization

NASA Astrophysics Data System (ADS)

Shikoh, Ali Sephar; Ahmad, Zubair; Touati, Farid; Al-Muhtaseb, Shaheen A.

2018-04-01

This paper deals with the electrical, optical and electrochemical properties of a metal-free dye C78H74O8 (AS-2), which has been used to improve the photo-detection properties of C58H86N8O8RuS2 (N719) based Dye sensitized photo-sensors (DSPSs). Both dyes were mixed together in various proportions and the most promising ratio N719/AS-2 (1:0.25) was selected for staining photo-anodes for DSPS integration. The fabricated DSPSs were studied in terms of electrical parameters and photodetection properties. The N719/AS-2 (1:0.25) based DSPS were found to have a reduced leakage current, increased breakdown voltage and a closer proximity to an ideal diode, as compared to the N719 based DSPS. Further, the N719/AS-2 (1:0.25) based DSPS was also found to have better linearity at high irradiance levels, thus rendering the co-sensitized device useful as a photosensor in various applications. Electrochemical Impedance Spectroscopy (EIS) analysis was also performed to explain the interfacial charge recombination process.

Comparative study on deposition of fluorine-doped tin dioxide thin films by conventional and ultrasonic spray pyrolysis methods for dye-sensitized solar modules

NASA Astrophysics Data System (ADS)

Icli, Kerem Cagatay; Kocaoglu, Bahadir Can; Ozenbas, Macit

2018-01-01

Fluorine-doped tin dioxide (FTO) thin films were produced via conventional spray pyrolysis and ultrasonic spray pyrolysis (USP) methods using alcohol-based solutions. The prepared films were compared in terms of crystal structure, morphology, surface roughness, visible light transmittance, and electronic properties. Upon investigation of the grain structures and morphologies, the films prepared using ultrasonic spray method provided relatively larger grains and due to this condition, carrier mobilities of these films exhibited slightly higher values. Dye-sensitized solar cells and 10×10 cm modules were prepared using commercially available and USP-deposited FTO/glass substrates, and solar performances were compared. It is observed that there exists no remarkable efficiency difference for both cells and modules, where module efficiency of the USP-deposited FTO glass substrates is 3.06% compared to commercial substrate giving 2.85% under identical conditions. We demonstrated that USP deposition is a low cost and versatile method of depositing commercial quality FTO thin films on large substrates employed in large area dye-sensitized solar modules or other thin film technologies.

Optimization studies of bio-hydrogen production in a coupled microbial electrolysis-dye sensitized solar cell system.

PubMed

Ajayi, Folusho Francis; Kim, Kyoung-Yeol; Chae, Kyu-Jung; Choi, Mi-Jin; Chang, In Seop; Kim, In S

2010-03-01

Bio-hydrogen production in light-assisted microbial electrolysis cell (MEC) with a dye sensitized solar cell (DSSC) was optimized by connecting multiple MECs to a single dye (N719) sensitized solar cell (V(OC) approx. 0.7 V). Hydrogen production occurred simultaneously in all the connected MECs when the solar cell was irradiated with light. The amount of hydrogen produced in each MEC depends on the activity of the microbial catalyst on their anode. Substrate (acetate) to hydrogen conversion efficiencies ranging from 42% to 65% were obtained from the reactors during the experiment. A moderate light intensity of 430 W m(-2) was sufficient for hydrogen production in the coupled MEC-DSSC. A higher light intensity of 915 W m(-2), as well as an increase in substrate concentration, did not show any improvement in the current density due to limitation caused by the rate of microbial oxidation on the anode. A significant reduction in the surface area of the connected DSSC only showed a slight effect on current density in the coupled MEC-DSSC system when irradiated with light.

Sensitive spectrophotometric determination of aceclofenac following azo dye formation with 4-carboxyl-2,6-dinitrobenzene diazonium ion.

PubMed

Aderibigbe, Segun A; Adegoke, Olajire A; Idowu, Olakunle S; Olaleye, Sefiu O

2012-01-01

The study is a description of a sensitive spectrophotometric determination of aceclofenac following azo dye formation with 4-carboxyl-2,6-dinitrobenzenediazonium ion (CDNBD). Spot test and thin layer chromatography revealed the formation of a new compound distinct from CDNBD and aceclofenac. Optimization studies established a reaction time of 5 min at 30 degrees C after vortex mixing the drug/CDNBD for 10 s. An absorption maximum of 430 nm was selected as analytical wavelength. A linear response was observed over 1.2-4.8 μg/mL of aceclofenac with a correlation coefficient of 0.9983 and the drug combined with CDNBD at stoichiometric ratio of 2 : 1. The method has a limit of detection of 0.403 μg/mL, limit of quantitation of 1.22 μg/mL and is reproducible over a three day assessment. The method gave Sandell's sensitivity of 3.279 ng/cm2. Intra- and inter-day accuracies (in terms of errors) were less than 6% while precisions were of the order of 0.03-1.89% (RSD). The developed spectrophotometric method is of equivalent accuracy (p > 0.05) with British Pharmacopoeia, 2010 potentiometric method. It has the advantages of speed, simplicity, sensitivity and more affordable instrumentation and could found application as a rapid and sensitive analytical method of aceclofenac. It is the first described method by azo dye derivatization for the analysis of aceclofenac in bulk samples and dosage forms.

Discovery of S···C≡N Intramolecular Bonding in a Thiophenylcyanoacrylate-Based Dye: Realizing Charge Transfer Pathways and Dye···TiO 2 Anchoring Characteristics for Dye-Sensitized Solar Cells

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

Cole, Jacqueline M.; Blood-Forsythe, Martin A.; Lin, Tze-Chia

Donor-pi-acceptor dyes containing thiophenyl pi-conjugated units and cyanoacrylate acceptor groups are among the best-performing organic chromophores used in dye-sensitized solar cell (DSC) applications. Yet, the molecular origins of their high photovoltaic output have remained unclear until now. This synchrotron-based X-ray diffraction study elucidates these origins for the high-performance thiophenylcyanoacrylate-based dye MK-2 (7.7% DSC device efficiency) and its molecular building block, MK-44. The crystal structures of MK-2 and MK-44 are both determined, while a high-resolution charge-density mapping of the smaller molecule was also possible, enabling the nature of its bonding to be detailed. A strong S center dot center dot centermore » dot C equivalent to N intramolecular interaction is discovered, which bears a bond critical point, thus proving that this interaction should be formally classified as a chemical bond. A topological analysis of the pi-conjugated portion of MK-44 shows that this S center dot center dot center dot C equivalent to N bonding underpins the highly efficient intramolecular charge transfer(ICT) in thiophenylcyanoacrylate dyes. This manifests as two bipartite ICT pathways bearing carboxylate and nitrile end points. In turn, these pathways dictate a preferred COO/CN anchoring mode for the dye as it adsorbs onto TiO2 surfaces, to form the dye TiO2 interface that constitutes the DSC working electrode. These results corroborate a recent proposal that all cyanoacrylate groups anchor onto TiO2 in this COO/CN binding configuration. Conformational analysis of the MK-44 and MK-2 crystal structures reveals that this S center dot center dot center dot C equivalent to N bonding will persist in MK-2. Accordingly, this newly discovered bond affords a rational explanation for the attractive photovoltaic properties of,MK-2. More generally, this study provides the first unequivocal evidence for an S center dot center dot center dot C equivalent to N interaction, confirming previous speculative assignments of such interactions in other compounds.« less

Discovery of S···C≡N Intramolecular Bonding in a Thiophenylcyanoacrylate-Based Dye: Realizing Charge Transfer Pathways and Dye···TiO2 Anchoring Characteristics for Dye-Sensitized Solar Cells.

PubMed

Cole, Jacqueline M; Blood-Forsythe, Martin A; Lin, Tze-Chia; Pattison, Philip; Gong, Yun; Vázquez-Mayagoitia, Álvaro; Waddell, Paul G; Zhang, Lei; Koumura, Nagatoshi; Mori, Shogo

2017-08-09

Donor-π-acceptor dyes containing thiophenyl π-conjugated units and cyanoacrylate acceptor groups are among the best-performing organic chromophores used in dye-sensitized solar cell (DSC) applications. Yet, the molecular origins of their high photovoltaic output have remained unclear until now. This synchrotron-based X-ray diffraction study elucidates these origins for the high-performance thiophenylcyanoacrylate-based dye MK-2 (7.7% DSC device efficiency) and its molecular building block, MK-44. The crystal structures of MK-2 and MK-44 are both determined, while a high-resolution charge-density mapping of the smaller molecule was also possible, enabling the nature of its bonding to be detailed. A strong S···C≡N intramolecular interaction is discovered, which bears a bond critical point, thus proving that this interaction should be formally classified as a chemical bond. A topological analysis of the π-conjugated portion of MK-44 shows that this S···C≡N bonding underpins the highly efficient intramolecular charge transfer (ICT) in thiophenylcyanoacrylate dyes. This manifests as two bipartite ICT pathways bearing carboxylate and nitrile end points. In turn, these pathways dictate a preferred COO/CN anchoring mode for the dye as it adsorbs onto TiO 2 surfaces, to form the dye···TiO 2 interface that constitutes the DSC working electrode. These results corroborate a recent proposal that all cyanoacrylate groups anchor onto TiO 2 in this COO/CN binding configuration. Conformational analysis of the MK-44 and MK-2 crystal structures reveals that this S···C≡N bonding will persist in MK-2. Accordingly, this newly discovered bond affords a rational explanation for the attractive photovoltaic properties of MK-2. More generally, this study provides the first unequivocal evidence for an S···C≡N interaction, confirming previous speculative assignments of such interactions in other compounds.

Analysis of in vivo penetration of textile dyes causing allergic reactions

NASA Astrophysics Data System (ADS)

Lademann, J.; Patzelt, A.; Worm, M.; Richter, H.; Sterry, W.; Meinke, M.

2009-10-01

Contact allergies to textile dyes are common and can cause severe eczema. In the present study, we investigated the penetration of a fluorescent textile dye, dissolved from a black pullover, into the skin of one volunteer during perspiration and nonperspiration. Previously, wearing this pullover had induced a severe contact dermatitis in an 82-year old woman, who was not aware of her sensitization to textile dyes. The investigations were carried out by in vivo laser scanning microscopy. It could be demonstrated that the dye was eluted from the textile material by sweat. Afterwards, the dye penetrated into the stratum corneum and into the hair follicles. Inside the hair follicles, the fluorescent signal was still detectable after 24 h, whereas it was not verifiable anymore in the stratum corneum, Laser scanning microscopy represents an efficient tool for in vivo investigation of the penetration and storage of topically applied substances and allergens into the human skin and reveals useful hints for the development and optimization of protection strategies.

Optimizing TiO2 nanotube top geometry for use in dye-sensitized solar cells.

PubMed

Mir, Nooshin; Lee, Kiyoung; Paramasivam, Indhumati; Schmuki, Patrik

2012-09-17

Recombination dynamics: For TiO(2) nanotube-based dye-sensitized solar cells, the efficiency can be drastically enhanced by a synergetic effect that occurs when using nanowire-ended nanotubes in combination with an adequate nanoparticle decoration (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A hybrid nanostructure of platinum-nanoparticles/graphitic-nanofibers as a three-dimensional counter electrode in dye-sensitized solar cells.

PubMed

Hsieh, Chien-Kuo; Tsai, Ming-Chi; Su, Ching-Yuan; Wei, Sung-Yen; Yen, Ming-Yu; Ma, Chen-Chi M; Chen, Fu-Rong; Tsai, Chuen-Horng

2011-11-07

We directly synthesized a platinum-nanoparticles/graphitic-nanofibers (PtNPs/GNFs) hybrid nanostructure on FTO glass. We applied this structure as a three-dimensional counter electrode in dye-sensitized solar cells (DSSCs), and investigated the cells' photoconversion performance. This journal is © The Royal Society of Chemistry 2011

Fast simultaneous assessment of renal and liver function using polymethine dyes in animal models of chronic and acute organ injury.

PubMed

Press, A T; Butans, M J; Haider, T P; Weber, C; Neugebauer, S; Kiehntopf, M; Schubert, U S; Clemens, M G; Bauer, M; Kortgen, A

2017-11-13

Simultaneous assessment of excretory liver and kidney function is still an unmet need in experimental stress models as well as in critical care. The aim of the study was to characterize two polymethine-dyes potentially suitable for this purpose in vivo. Plasma disappearance rate and elimination measurements of simultaneously injected fluorescent dyes DY-780 (hepato-biliary elimination) and DY-654(renal elimination) were conducted using catheter techniques and intravital microscopy in animals subjected to different organ injuries, i.e. polymicrobial sepsis by peritoneal contamination and infection, ischemia-reperfusion-injury and glycerol-induced acute kidney-injury. DY-780 and DY-654 showed organ specific and determined elimination routes in both healthy and diseased animals. They can be measured simultaneously using near-infrared imaging and spectrophotometry. Plasma-disappearance rates of DY-780 and DY-654 are superior to conventional biomarkers in indicating hepatic or kidney dysfunction in different animal models. Greatest impact on liver function was found in animals with polymicrobial sepsis whereas glomerular damage due to glycerol-induced kidney-injury had strongest impact on DY-654 elimination. We therefore conclude that hepatic elimination and renal filtration can be assessed in rodents measuring plasma-disappearance rates of both dyes. Further, assessment of organ dysfunction by polymethine dyes correlates with, but outperforms conventional biomarkers regarding sensitivity and the option of spatial resolution if biophotonic strategies are applied. Polymethine-dye clearance thereby allows sensitive point-of-care assessment of both organ functions simultaneously.

Mesoporous multi-shelled ZnO microspheres for the scattering layer of dye sensitized solar cell with a high efficiency

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

Xia, Weiwei; Mei, Chao; Zeng, Xianghua, E-mail: xhzeng@yzu.edu.cn

2016-03-14

Both light scattering and dye adsorbing are important for the power conversion efficiency PCE performance of dye sensitized solar cell (DSSC). Nanostructured scattering layers with a large specific surface area are regarded as an efficient way to improve the PCE by increasing dye adsorbing, but excess adsorbed dye will hinder light scattering and light penetration. Thus, how to balance the dye adsorbing and light penetration is a key problem to improve the PCE performance. Here, multiple-shelled ZnO microspheres with a mesoporous surface are fabricated by a hydrothermal method and are used as scattering layers on the TiO{sub 2} photoanode ofmore » the DSSC in the presence of N719 dye and iodine–based electrolyte, and the results reveal that the DSSCs based on triple shelled ZnO microsphere with a mesoporous surface exhibit an enhanced PCE of 7.66%, which is 13.0% higher than those without the scattering layers (6.78%), indicating that multiple-shelled microspheres with a mesoporous surface can ensure enough light scattering between the shells, and a favorable concentration of the adsorbed dye can improve the light penetration. These results may provide a promising pathway to obtain the high efficient DSSCs.« less

Tuning the Electron-Transport and Electron-Accepting Abilities of Dyes through Introduction of Different π-Conjugated Bridges and Acceptors for Dye-Sensitized Solar Cells.

PubMed

Li, Yuanzuo; Sun, Chaofan; Song, Peng; Ma, Fengcai; Yang, Yanhui

2017-02-17

A series of dyes, containing thiophene and thieno[3,2-b]thiophene as π-conjugated bridging units and six kinds of groups as electron acceptors, were designed for dye-sensitized solar cells (DSSCs). The ground- and excited-state properties of the designed dyes were investigated by using density functional theory (DFT) and time-dependent DFT, respectively. Moreover, the parameters affecting the short-circuit current density and open-circuit voltage were calculated to predict the photoelectrical performance of each dye. In addition, the charge difference density was presented through a three-dimensional (3D) real-space analysis method to investigate the electron-injection mechanism in the complexes. Our results show that the longer conjugated bridge would inhibit the intramolecular charge transfer, thereby affecting the photoelectrical properties of DSSCs. Similarly, owing to the lowest chemical hardness, largest electron-accepting ability, dipole moment (μnormal ) and the change in the energy of the TiO 2 conduction band (ΔECB ), the dye with a (E)-3-(4-(benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-2-cyanoacrylic acid (TCA) acceptor group would exhibit the most significant photoelectrical properties among the designed dyes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficient platinum-free counter electrodes for dye-sensitized solar cell applications.

PubMed

Ahmad, Shahzada; Yum, Jun-Ho; Butt, Hans-Jürgen; Nazeeruddin, Mohammad K; Grätzel, Michael

2010-09-10

Nanoporous layers of poly(3,4-propylenedioxythiophene) (PProDOT) were fabricated by electrical-field-assisted growth using hydrophobic ionic liquids as the growing medium. A series of PProDoT layers was prepared with three different ionic liquids to control the microstructure and electrochemical properties of the resulting dye-sensitized solar cells, which were highly efficient and showed a power conversion efficiency of >9% under different sunlight intensities. The current-voltage characteristics of the counter electrodes varied depending on the ionic liquids used in the synthesis of PProDOT. The most hydrophobic ionic liquids exhibited high catalytic properties, thus resulting in high power conversion efficiency and allowing the fabrication of platinum-free, stable, flexible, and cost-effective dye-sensitized solar cells.

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

Yen, Chih-Ping; Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan; Yu, Pin-Feng

The deposition of various distinct organic dyes, including ruthenium complex N3, melanin nanoparticle (MNP), and porphyrin-based donor-π-acceptor dye YD2-o-C8, by using matrix-assisted pulsed laser evaporation (MAPLE) for application to dye-sensitized solar cell (DSSC) is investigated systematically. It is found that the two covalently-bonded organic molecules, i.e., MNP and YD2-o-C8, can be transferred from the frozen target to the substrate with maintained molecular integrity. In contrast, N3 disintegrates in the process, presumably due to the lower bonding strength of metal complex compared to covalent bond. With the method, DSSC using YD2-o-C8 is fabricated, and an energy conversion efficiency of 1.47% ismore » attained. The issue of the low penetration depth of dyes deposited by MAPLE and the possible resolution to it are studied. This work demonstrates that MAPLE could be an alternative way for deposition of organic dyes for DSSC.« less

Molecular Engineering, Photophysical and Electrochemical Characterizations of Novel Ru(II) and BODIPY Sensitizers for Mesoporous TiO2 Solar Cells

NASA Astrophysics Data System (ADS)

Cheema, Hammad Arshad

To realize the dream of a low carbon society and ensure the wide spread application of renewable energy sources such as solar energy, photovoltaic devices should be highly efficient, cost-effective and stable for at least 20 years. Dye sensitized solar cells (DSCs) are photovoltaic cells that mimic the natural photosynthesis. In a DSC, the dye absorbs photons from incident light and converts those photons to electric charges, which are then extracted to the outer circuit through semiconductor TiO2, whereas the mediator regenerates the oxidized dye. A sensitizer is the pivotal component in the device in terms of determining the spectral response, color, photocurrent density, long term stability, and thickness of a DSC. The breakthrough report by O'Regan and Gratzel in 1991 has garnered more than 18,673 citations (as of October 9, 2014), which indicates the immense scientific interest to better understand and improve the fundamental science of this technology. With the aforementioned in mind, this study has focused on the molecular engineering of novel sensitizers to provide a better understanding of structure-property relationships of novel sensitizers for DSCs. The characterization of sensitizers (HD-1-mono, HD-2-mono and HD-2) for photovoltaic applications showed that the photocurrent response of DSCs can be increased by using mono-ancillary ligand instead of bis-ancillary ligands, which is of great commercial value considering the difference in the molecular weights of both dyes. The results of this work were published in Journal of Materials Chemistry A (doi:10.1039/c4ta01942c) and ACS Applied Materials and Interfaces (doi: 10.1021/am502400b). Furthermore, structure-property relationships were investigated in Ru (II) sensitizers HL-41 and HL-42 in order to elucidate the steric effects of electron donating ancillary ligands on photocurrent and photovoltage, as discussed in Chapter 4. It was found that the electron donating group (ethoxy) ortho to the CH=CH spacer precludes coplanarity of the naphthalene moiety, thus decreasing the extracted photocurrent response from solar device. The findings were published in Dyes and Pigments (doi:10.1016/j.dyepig.2014.08.005). For HD-7 and HD-8, intriguing difference caused by structural isomerization based on anthracene and phenanthrene stilbazole type ancillary ligands, respectively in Ru (II) sensitizers was investigated using femtosecond transient absorption spectroscopy. It was found that the excited electrons in HD-7 are prone to ISC (intersystem crossing) much more than that in HD-8 and those triplet electrons are not being injected in TiO2 efficiently as discussed in Chapter 5. To achieve long term stability, we combined the strong electron donor characteristics of carbazole and the hydrophobic nature of long alkyl chains, C7 (HD-14 ), C18 (HD-15) and C2 (NCSU-10), tethered to N-carbazole. HD-15 showed strikingly good long term light soaking stability and maintained up to 98% of initial efficiency value compared to 92% for HD-14 and 78% for NCSU-10, as discussed in Chapter 6. Boron dipyromethene (BODIPY) dyes HB-1, HB-2 and HB-3 were synthesized and fully characterized for dye solar cells. It was found that having long alkyl chains tethered to the donor groups alone are not sufficient for achieving highly efficient photovoltaic response from BODIPY dyes (Chapter 7). Thus, replacement of fluorines from BODIPY core with long alkoxy chains has been suggested for future work.

Effect of composition of chlorophyll and ruthenium dyes mixture (hybrid) on the dye-sensitized solar cell performance

NASA Astrophysics Data System (ADS)

Pratiwi, D. D.; Nurosyid, F.; Kusumandari; Supriyanto, A.; Suryana, R.

2018-03-01

The fabrication of dye-sensitized solar cell (DSSC) has been conducted by varying the composition of natural dye from moss chlorophyll (Bryophyte) and synthesis dye from ruthenium complex N719. The sandwich structure of DSSC consists of the working electrode using TiO2, dye, electrolyte, and counter electrode using carbon. The composition of chlorophyll and synthesis dyes mixture were 100% and 0%, 80% and 20%, 60% and 40%, 40% and 60%, and 20% and 80%. The UV-Vis absorption spectra of moss chlorophyll showed the first peak in the wavelength range of 450-500 nm and the second peak at wavelength of 650-700 nm. The peak value of absorbance at wavelengths of 450-500 nm was 6.1004 and at wavelengths of 650-700 nm was 3.5835. The IPCE characteristic curves showed the absorption peak of photon for DSSCs occurred at wavelength of 550-650 nm. It considered that photon in this wavelength can contribute dominantly to produce the optimum electrons. The I-V characteristics of DSSCs with composition of chlorophyll and synthesis dyes mixture of 100% and 0%, 80% and 20%, 60% and 40%, 40% and 60%, and 20% and 80% resulted the efficiency of 0.0022; 0.0194; 0.0239; 0.0342; and 0.0414, respectively. It suggested that the addition of a little composition of the ruthenium complex dye into moss chlorophyll dye can increase the efficiency significantly.

Property influence of polyanilines on photovoltaic behaviors of dye-sensitized solar cells.

PubMed

Tan, Shuxin; Zhai, Jin; Xue, Bofei; Wan, Meixiang; Meng, Qingbo; Li, Yuliang; Jiang, Lei; Zhu, Daoben

2004-03-30

The influence of polyanilines (PANIs) as hole conductors on the photovoltaic behaviors of dye-sensitized solar cells is studied. The current-voltage (I-V) characteristics and the incident photon to current conversion efficiency (IPCE) curves of the devices are determined as the function of different conductivities and morphologies of PANIs. The results show that the conductivity of PANIs affects the performance of the devices greatly, and PANI with the intermediate conductivity value (3.5 S/cm) is optimum. In addition, the effects of both the film formation property and the cluster size of polyanilines on the photovoltaic behaviors of the devices are also discussed.

TiO2 dye sensitized solar cell (DSSC): linear relationship of maximum power point and anthocyanin concentration

NASA Astrophysics Data System (ADS)

Ahmadian, Radin

2010-09-01

This study investigated the relationship of anthocyanin concentration from different organic fruit species and output voltage and current in a TiO2 dye-sensitized solar cell (DSSC) and hypothesized that fruits with greater anthocyanin concentration produce higher maximum power point (MPP) which would lead to higher current and voltage. Anthocyanin dye solution was made with crushing of a group of fresh fruits with different anthocyanin content in 2 mL of de-ionized water and filtration. Using these test fruit dyes, multiple DSSCs were assembled such that light enters through the TiO2 side of the cell. The full current-voltage (I-V) co-variations were measured using a 500 Ω potentiometer as a variable load. Point-by point current and voltage data pairs were measured at various incremental resistance values. The maximum power point (MPP) generated by the solar cell was defined as a dependent variable and the anthocyanin concentration in the fruit used in the DSSC as the independent variable. A regression model was used to investigate the linear relationship between study variables. Regression analysis showed a significant linear relationship between MPP and anthocyanin concentration with a p-value of 0.007. Fruits like blueberry and black raspberry with the highest anthocyanin content generated higher MPP. In a DSSC, a linear model may predict MPP based on the anthocyanin concentration. This model is the first step to find organic anthocyanin sources in the nature with the highest dye concentration to generate energy.

Optimization of Diamond Nucleic Acid Dye for quantitative PCR.

PubMed

Haines, Alicia M; Tobe, Shanan S; Linacre, Adrian

2016-10-01

Here, we evaluate Diamond Nucleic Acid Dye (DD) for use in quantitative PCR (qPCR) applications. Although DD is a commercially available stain for detection of DNA separated by gel electrophoresis, its use as a detection dye in qPCR has yet to be described. To determine if DD can be used in qPCR, we investigated its inhibitory effects on qPCR at concentrations ranging 0.1-2.5×. Serial dilution of DNA was used to determine the efficiency, sensitivity, and linearity of DD-generated qPCR data in comparison to other commonly used fluorescent dyes such as SYBR Green (SG), EvaGreen (EG), and BRYT Green (BG). DD was found to be comparable with other dyes for qPCR applications, with an R2 value >0.9 and an efficiency of 0.83. Mitochondrial DNA (mtDNA) target signals were successfully produced by DD over a DNA dilution range of ~28 ng- 0.28 pg, demonstrating comparable sensitivity to the other dyes investigated. Cq values obtained using DD were lower than those using EG by almost 7 cycles. We conclude that Diamond Nucleic Acid Dye is a cheaper, less toxic alternative for qPCR applications.

Sorption of hydrophilic dyes on anodic aluminium oxide films and application to pH sensing.

PubMed

Silina, Yuliya E; Kuchmenko, Tatyana A; Volmer, Dietrich A

2015-02-07

The sorption of selected hydrophilic pH-sensitive dyes (bromophenol blue, bromothymol blue, bromocresol purple, alizarin red, methyl orange, congo red, rhodamine 6G) on films of anodized aluminium oxide (AAO) was investigated in this study. Depth and pore structure of the AAO channels were adjusted by changing electrolysis time and current density during treatment of aluminium foil in oxalic acid, sulfosalycilic acid and sulfuric acid at concentration levels between 0.2 and 0.6 M. The dyes were immobilized on the AAO surface by direct saturation of the films in dye solutions. It was shown by scanning electron microscopy and X-ray spectral analysis that the dyes penetrated into the AAO channels by more than 1.5 μm, even at static saturation conditions. The anionic dyes linked to the porous AAO surface exhibited differential shifts of the UV absorption bands in their acidic/basic forms. By combining several dyes, the films have an application range between pH = 0.5-9 in aqueous media. The dye-modified AAO film was a simple, portable, inexpensive and reusable pH sensor with very fast response time and clear colour transitions.

Novel method for evaluation of natural dyes in DSSC

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

Lakshmi, M.; Kavitha, S.; Paul, Mercyleena

Dye sensitized Solar Cell (DSSC) is presently centered on Ruthenium based dyes. Recent research is diverted to explore the potential of natural dyes in replacing the conventional dyes. In this work we have chosen few natural dyes, which when coated on TiO{sub 2} leads to increase in absorption capacity of TiO{sub 2}. Co-relation of absorption and electrochemical properties of natural dyes gives a scientific insight of the probable performance of a dye, even without fabricating a cell. We have tried to compare this predictions based on HOMO-LUMO energy levels with the real cell performance. Measurements of cell parameters suggest thatmore » there is scope for further research in this area.« less

New Dye-Sensitized Solar Cells Obtained from Extracted Bracts of Bougainvillea Glabra and Spectabilis Betalain Pigments by Different Purification Processes

PubMed Central

Hernandez-Martinez, Angel Ramon; Estevez, Miriam; Vargas, Susana; Quintanilla, Fracisco; Rodriguez, Rogelio

2011-01-01

The performance of a new dye-sensitized solar cell (DSSC) based in a natural dye extracted from the Bougainvillea spectabilis’ bracts, is reported. The performance of this solar cell was compared with cells prepared using extract of the Bougainvillea glabra and mixture of both extracts; in both cases the pigments were betalains, obtained from Reddish-purple extract. These dyes were purified to different extents and used for the construction of solar cells that were electrically characterized. The materials were characterized using FTIR and UV-Vis. Solar cells were assembled using TiO2 thin film on indium tin oxide (ITO)-coated glass; a mesoporous film was sensitized with the Bougainvillea extracts. The obtained solar energy conversion efficiency was of 0.48% with a current density JSC of 2.29 mA/cm2 using an irradiation of 100 mW/cm2 at 25 °C. PMID:22016609

Monodispersed Zinc Oxide Nanoparticle-Dye Dyads and Triads

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

Gladfelter, Wayne L.; Blank, David A.; Mann, Kent R.

The overall energy conversion efficiency of photovoltaic cells depends on the combined efficiencies of light absorption, charge separation and charge transport. Dye-sensitized solar cells are photovoltaic devices in which a molecular dye absorbs light and uses this energy to initiate charge separation. The most efficient dye-sensitized solar cells (DSSCs) use nanocrystal titanium dioxide films to which are attached ruthenium complexes. Numerous studies have provided valuable insight into the dynamics of these and analogous photosystems, but the lack of site homogeneity in binding dye molecules to metal oxide films and nanocrystals (NCs) is a significant impediment to extracting fundamental details aboutmore » the electron transfer across the interface. Although zinc oxide is emerging as a potential semiconducting component in DSSCs, there is less known about the factors controlling charge separation across the dye/ZnO interface. Zinc oxide crystallizes in the wurtzite lattice and has a band gap of 3.37 eV. One of the features that makes ZnO especially attractive is the remarkable ability to control the morphology of the films. Using solution deposition processes, one can prepare NCs, nanorods and nanowires having a variety of shapes and dimensions. This project solved problems associated with film heterogeneity through the use of dispersible sensitizer/ZnO NC ensembles. The overarching goal of this research was to study the relationship between structure, energetics and dynamics in a set of synthetically controlled donor-acceptor dyads and triads. These studies provided access to unprecedented understanding of the light absorption and charge transfer steps that lie at the heart of DSSCs, thus enabling significant future advances in cell efficiencies. The approach began with the construction of well-defined dye-NC dyads that were sufficiently dispersible to allow the use of state of the art pulsed laser spectroscopic and kinetic methods to understand the charge transfer events at a fundamental level. This was combined with the synthesis of a broad range of sensitizers that provide systematic variation of the energetics, excited state dynamics, structure and interfacial bonding. The key is that the monodisperse nature and high dispersibility of the ZnO NCs made these experiments reproducible; in essence, the measurements were on discrete molecular species rather than on the complicated mixtures that resulted from the typical fabrication of functional photovoltaic cells. The monodispersed nature of the NCs also allowed the use of quantum confinement to investigate the role of donor/acceptor energetic alignment in chemically identical systems. The results added significantly to our basic understanding of energy and charge transfer events at molecule-semiconductor interfaces and will help the R&D community realize zinc oxide's full potential in solar cell applications.« less

Surface plasmon resonance effect of silver nanoparticles on a TiO2 electrode for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Jung, Haeng-Yun; Yeo, In-Seon; Kim, Tae-Un; Ki, Hyun-Chul; Gu, Hal-Bon

2018-02-01

In this study, we exploit local surface plasmon resonance (LSPR) in order to improve the efficiency of dye-sensitized solar cells (DSSCs). In order to investigate the effect of LSPR, Ag nanoparticles of several sizes were formed using electro-beam equipment; sizes were varied by changing the annealing time. DSSCs were fabricated by coating Ag nanoparticles onto a TiO2 thin film. Finally, TiO2 nanoparticles were layered onto the Ag nanoparticles via a titanium tetra-isopropoxide (TTIP) treatment. This study used nanoparticle-coated TiO2 thin films as photoelectrodes, and manufactured the cell in the unit of the DSSCs. We compared the behavior of the electrical properties of DSSCs depending on the presence or absence of Ag nanoparticles, as well as on the nanoparticle size. The Ag particles did not affect dye adsorption because the content of Ag particles is very low (0.13%) compared to that in TiO2 in the photoelectrode. The DSSCs with LSPR showed increased electric current density compared to those without LSPR, and improved the solar conversion efficiency (η) by 24%. The current density of the DSSCs increased because the light absorption of the dye increased. Therefore, we determined that LSPR affects the electrical properties of DSSCs.

Insight into the effects of modifying chromophores on the performance of quinoline-based dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Mao, Mao; Wang, Jian-Bo; Liu, Xiu-Lin; Wu, Guo-Hua; Fang, Xia-Qin; Song, Qin-Hua

2018-02-01

A series of organic dyes based on quinoline as an electron-deficient π-linker, were designed and synthesized for dye sensitized solar cells (DSSC) application. These push-pull conjugated dyes, sharing same anchoring group with distinctive electron-rich donating groups such as N,N-diethyl (DEA-Q), 3,6-dimethoxy carbazole (CBZ-Q), bis(4-butoxyphenyl)amine (BPA-Q), were synthesized by Riley oxidation of sbnd CH3 followed by Knoevenagel condensation of the corresponding aldehyde precursors 2a-c with cyanoacrylic acid. The optical, electrochemical, theoretical calculation and photovoltaic properties with these three dyes were systematically investigated. Compared to DEA-Q and CBZ-Q, BPA-Q possesses better light harvesting properties with regard to extended conjugate length, red-shifted intramolecular charge transfer band absorption and broaden light-responsive IPCE spectrum, resulting in a greater short circuit photocurrent density output. BPA-Q also has improved open-circuit voltage due to the apparent large charge recombination resistance. Consequently, assembled with iodine redox electrolytes, the device with BPA-Q achieved the best overall conversion efficiency value of 3.07% among three dyes under AM 1.5G standard conditions. This present investigation demonstrates the importance of various N-substituent chromophores in the prevalent D-π-A type organic sensitizers for tuning the photovoltaic performance of their DSSCs.

ZnO Photoanode Effect on the Efficiency Performance of Organic Based Dye Sensitized Solar Cell

NASA Astrophysics Data System (ADS)

Mohamad, I. S.; Ismail, S. S.; Norizan, M. N.; Murad, S. A. Z.; Abdullah, M. M. A.

2017-06-01

Dye sensitized solar cell has been emerged as one of the most promising candidates for photovoltaics applications in good quality of their low manufacturing cost and impressive conversion energy. Titanium dioxide (TiO2) which is used as photoanode in the market has the advantage of wide bandgap energy but low in electron mobility (∼10 cm2/(V.s)). Ruthenium in the other hand, as the dye sensitizer is a rare noble metal and harmful to human health. Thus, this article reveals the performance of photo-to-electric conversion efficiency with the usage of Zinc Oxide as photoanode with higher electron mobility (155 cm2/(V.s)) compared to TiO2 utilizing three natural fruit dyes of Prunus domestica, Magnifera indica and Citrus limon. ZnO and TiO2 photoanodes were fabricated using sol gel and dr blade method respectively. The morphology of the photoanodes were characterized using Scanning Electron Microscope and the efficiency of the complete DSSC with all different fruit dyes were characterized using Semiconductor Parametric Analyzer. The different property of electron mobility photoanodes effect in DSSC proved to give better performance with the photoconversion efficiency of 3.082% using ZnO with Prunus domestica dye. This article also reveals that pH indicator does not affect the selection and the performance of DSSC.

A stereo-compound hybrid microscope for combined intracellular and optical recording of invertebrate neural network activity.

PubMed

Frost, William N; Wang, Jean; Brandon, Christopher J

2007-05-15

Optical recording studies of invertebrate neural networks with voltage-sensitive dyes seldom employ conventional intracellular electrodes. This may in part be due to the traditional reliance on compound microscopes for such work. While such microscopes have high light-gathering power, they do not provide depth of field, making working with sharp electrodes difficult. Here we describe a hybrid microscope design, with switchable compound and stereo objectives, that eases the use of conventional intracellular electrodes in optical recording experiments. We use it, in combination with a voltage-sensitive dye and photodiode array, to identify neurons participating in the swim motor program of the marine mollusk Tritonia. This microscope design should be applicable to optical recording studies in many preparations.

A comparative study between titania and zirconia as material for scattering layer in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Nursam, N. M.; Hidayat, J.; Shobih; Rosa, E. S.; Pranoto, L. M.

2018-04-01

The photoanode of dye-sensitized solar cells (DSSC) is typically composed of nanocrystalline titania (TiO2) layer that has been sensitized with light-absorbing dye molecules. Large portion of the light, however, could not be efficiently absorbed due to some physical reasons, such as TiO2 crystal size (typically 10-25 nm) that makes the photoanode remains partially transparent to the visible region in the solar spectrum. One of the ways to improve the light harvesting efficiency in DSSC could be achieved by employing an additional scattering layer over the TiO2 electron transport material. In this contribution, we evaluate the effect of light scattering properties on the performance of DSSC. Specifically, the light scattering properties provided from two different scattering materials, i.e. additional TiO2 scattering layer and zirconia (ZrO2) scattering layer, were compared. Both layers were deposited using screen printing technique under the same condition on top of 8 µm thick TiO2 photoanode layer. All samples subsequently received the same thermal annealing treatment at 500 °C and sensitized with ruthenium-based synthetic dyes. Our results revealed that the thickness of the scattering layer for both TiO2 and ZrO2 had a significant effect on the solar cell performance. The best photoconversion efficiency was achieved by samples that were coated with one screen-printing cycle, giving an overall efficiency of 3.50 % and 4.02% for TiO2 and ZrO2, respectively.

Rapid Synthesis of Thiophene-Based, Organic Dyes for Dye-Sensitized Solar Cells (DSSCs) by a One-Pot, Four-Component Coupling Approach.

PubMed

Matsumura, Keisuke; Yoshizaki, Soichi; Maitani, Masato M; Wada, Yuji; Ogomi, Yuhei; Hayase, Shuzi; Kaiho, Tatsuo; Fuse, Shinichiro; Tanaka, Hiroshi; Takahashi, Takashi

2015-06-26

This one-pot, four-component coupling approach (Suzuki-Miyaura coupling/C-H direct arylation/Knoevenagel condensation) was developed for the rapid synthesis of thiophene-based organic dyes for dye-sensitized solar cells (DSSCs). Seven thiophene-based, organic dyes of various donor structures with/without the use of a 3,4-ethylenedioxythiophene (EDOT) moiety were successfully synthesized in good yields based on a readily available thiophene boronic acid pinacol ester scaffold (one-pot, 3-step, 35-61%). Evaluation of the photovoltaic properties of the solar cells that were prepared using the synthesized dyes revealed that the introduction of an EDOT structure beside a cyanoacrylic acid moiety improved the short-circuit current (Jsc) while decreasing the fill factor (FF). The donor structure significantly influenced the open-circuit voltage (Voc), the FF, and the power conversion efficiency (PCE). The use of a n-hexyloxyphenyl amine donor, and our originally developed, rigid, and nonplanar donor, both promoted good cell performance (η=5.2-5.6%). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recording membrane potential changes through photoacoustic voltage sensitive dye

NASA Astrophysics Data System (ADS)

Zhang, Haichong K.; Kang, Jeeun; Yan, Ping; Abou, Diane S.; Le, Hanh N. D.; Thorek, Daniel L. J.; Kang, Jin U.; Gjedde, Albert; Rahmim, Arman; Wong, Dean F.; Loew, Leslie M.; Boctor, Emad M.

2017-03-01

Monitoring of the membrane potential is possible using voltage sensitive dyes (VSD), where fluorescence intensity changes in response to neuronal electrical activity. However, fluorescence imaging is limited by depth of penetration and high scattering losses, which leads to low sensitivity in vivo systems for external detection. In contrast, photoacoustic (PA) imaging, an emerging modality, is capable of deep tissue, noninvasive imaging by combining near infrared light excitation and ultrasound detection. In this work, we develop the theoretical concept whereby the voltage-dependent quenching of dye fluorescence leads to a reciprocal enhancement of PA intensity. Based on this concept, we synthesized a novel near infrared photoacoustic VSD (PA-VSD) whose PA intensity change is sensitive to membrane potential. In the polarized state, this cyanine-based probe enhances PA intensity while decreasing fluorescence output in a lipid vesicle membrane model. With a 3-9 μM VSD concentration, we measured a PA signal increase in the range of 5.3 % to 18.1 %, and observed a corresponding signal reduction in fluorescence emission of 30.0 % to 48.7 %. A theoretical model successfully accounts for how the experimental PA intensity change depends on fluorescence and absorbance properties of the dye. These results not only demonstrate the voltage sensing capability of the dye, but also indicate the necessity of considering both fluorescence and absorbance spectral sensitivities in order to optimize the characteristics of improved photoacoustic probes. Together, our results demonstrate photoacoustic sensing as a potential new modality for sub-second recording and external imaging of electrophysiological and neurochemical events in the brain.

Magnetic Spin Effects in Photoprocesses inside Polymeric Photoconductors

NASA Astrophysics Data System (ADS)

Rumyantsev, B. M.; Berendyaev, V. I.; Pebalk, A. V.

2018-06-01

Magnetic spin effects are detected and studied in the processes of sensitized current-carrier photogeneration and luminescence inside polymer photoconductor films based on polyimides and composites of polymers with carbazole moieties combined with electron acceptors (chemical sensitization) and dyes (spectral sensitization). The effect an electric field has on the quantum yield of photogeneration and the luminescence of excited charge-transfer complexes (reversible and irreversible effects) at spectral sensitization is studied in the presence of O2.

Plasmonic nanoparticles enhanced dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Xu, Qi; Liu, Fang; Meng, Weisi; Huang, Yidong

2013-12-01

Here we present investigations on utilizing two kinds of plasmonic nanoparticles (NPs) to enhance the efficiency of dye sensitized solar cells (DSCs). The Au@PVP NPs is proposed and present the specialty of adhesiveness to dye molecules, which could help to localize additional dye molecules near the plasmonic NPs, hence increasing the optical absorption consequently the power conversion efficiency (PCE) of the DSCs by 30% from 3.3% to 4.3%. Meanwhile, an irregular Au-Ag alloy popcorn-shaped NPs (popcorn NPs) with plenty of fine structures is also proposed and realized to enhance the light absorption of DSC. A pronounced absorption enhancement in a broadband wavelength range is observed due to the excitation of localized surface plasmon at different wavelengths. The PCE is enhanced by 32% from 5.94% to 7.85%.

Dye-sensitized MIL-101 metal organic frameworks loaded with Ni/NiOx nanoparticles for efficient visible-light-driven hydrogen generation

NASA Astrophysics Data System (ADS)

Liu, Xin-Ling; Wang, Rong; Zhang, Ming-Yi; Yuan, Yu-Peng; Xue, Can

2015-10-01

The Ni/NiOx particles were in situ photodeposited on MIL-101 metal organic frameworks as catalysts for boosting H2 generation from Erythrosin B dye sensitization under visible-light irradiation. The highest H2 production rate of 125 μmol h-1 was achieved from the system containing 5 wt. % Ni-loaded MIL-101 (20 mg) and 30 mg Erythrosin B dye. Moreover, the Ni/NiOx catalysts show excellent stability for long-term photocatalytic reaction. The enhancement on H2 generation is attributed to the efficient charge transfer from photoexcited dye to the Ni catalyst via MIL-101. Our results demonstrate that the economical Ni/NiOx particles are durable and active catalysts for photocatalytic H2 generation.

Influence of the Terminal Electron Donor in D-D-π-A Organic Dye-Sensitized Solar Cells: Dithieno[3,2-b:2',3'-d]pyrrole versus Bis(amine).

PubMed

Dai, Panpan; Yang, Lin; Liang, Mao; Dong, Huanhuan; Wang, Peng; Zhang, Chunyao; Sun, Zhe; Xue, Song

2015-10-14

With respect to the electron-withdrawing acceptors of D-A-π-A organic dyes, reports on the second electron-donating donors for D-D-π-A organic dyes are very limited. Both of the dyes have attracted significant attention in the field of dye-sensitized solar cells (DSCs). In this work, four new D-D-π-A organic dyes with dithieno[3,2-b:2',3'-d]pyrrole (DTP) or bis(amine) donor have been designed and synthesized for a investigation of the influence of the terminal electron donor in D-D-π-A organic dye-sensitized solar cells. It is found that DTP is a promising building block as the terminal electron donor when introduced in the dithiophenepyrrole direction, but not just a good bridge, which exhibits several characteristics: (i) efficiently increasing the maximum molar absorption coefficient and extending the absorption bands; (ii) showing stronger charge transfer interaction as compared with the pyrrole direction; (iii) beneficial to photocurrent generation of DSCs employing cobalt electrolytes. DSCs based on M45 with the Co-phen electrolyte exhibit good light-to-electric energy conversion efficiencies as high as 9.02%, with a short circuit current density (JSC) of 15.3 mA cm(-2), open circuit voltage (VOC) of 867 mV and fill factor (FF) of 0.68 under AM 1.5 illumination (100 mW cm(-2)). The results demonstrate that N,S-heterocycles such as DTP unit could be promising candidates for application in highly efficient DSCs employing cobalt electrolyte.

Environment sensitive fluorescent analogue of biologically active oxazoles differentially recognizes human serum albumin and bovine serum albumin: Photophysical and molecular modeling studies

NASA Astrophysics Data System (ADS)

Maiti, Jyotirmay; Biswas, Suman; Chaudhuri, Ankur; Chakraborty, Sandipan; Chakraborty, Sibani; Das, Ranjan

2017-03-01

An environment sensitive fluorophore, 4-(5-(4-(dimethylamino)phenyl)oxazol-2-yl)benzoic acid (DMOBA), that closely mimics biologically active 2,5-disubstituited oxazoles has been designed to probe two homologous serum proteins, human serum albumin (HSA) and bovine serum albumin (BSA) by means of photophysical and molecular modeling studies. This fluorescent analogue exhibits solvent polarity sensitive fluorescence due to an intramolecular charge transfer in the excited state. In comparison to water, the steady state emission spectra of DMOBA in BSA is characterized by a greater blue shift ( 10 nm) and smaller Stokes' shift ( 5980 cm- 1) in BSA than HSA (Stokes'shift 6600 cm- 1), indicating less polar and more hydrophobic environment of the dye in the former than the latter. The dye-protein binding interactions are remarkably stronger for BSA than HSA which is evident from higher value of the association constant for the DMOBA-BSA complex (Ka 5.2 × 106 M- 1) than the DMOBA-HSA complex (Ka 1.0 × 106 M- 1). Fӧrster resonance energy transfer studies revealed remarkably less efficient energy transfer (8%) between the donor tryptophans in BSA and the acceptor DMOBA dye than that (30%) between the single tryptophan moiety in HSA and the dye, which is consistent with a much larger distance between the donor (tryptophan)-acceptor (dye) pair in BSA (34.5 Å) than HSA (25.4 Å). Site specific competitive binding assays have confirmed on the location of the dye in Sudlow's site II of BSA and in Sudlow's site I of HSA, respectively. Molecular modeling studies have shown that the fluorescent analogue is tightly packed in the binding site of BSA due to strong steric complementarity, where, binding of DMOBA to BSA is primarily dictated by the van der Waals and hydrogen bonding interactions. In contrast, in HSA the steric complementarity is less significant and binding is primarily guided by polar interactions and van der Waals interactions appear to be less significant in the formation of the HSA-DMOBA complex. Electrostatic interactions contribute significantly in the binding of DMOBA to HSA (- 2.09 kcal/mol) compared to BSA (- 0.47 kcal/mol). Electrostatic surface potential calculation reveals that the DMOBA binding site within HSA is highly charged compared to BSA.

Listening to membrane potential: photoacoustic voltage-sensitive dye recording.

PubMed

Zhang, Haichong K; Yan, Ping; Kang, Jeeun; Abou, Diane S; Le, Hanh N D; Jha, Abhinav K; Thorek, Daniel L J; Kang, Jin U; Rahmim, Arman; Wong, Dean F; Boctor, Emad M; Loew, Leslie M

2017-04-01

Voltage-sensitive dyes (VSDs) are designed to monitor membrane potential by detecting fluorescence changes in response to neuronal or muscle electrical activity. However, fluorescence imaging is limited by depth of penetration and high scattering losses, which leads to low sensitivity in vivo systems for external detection. By contrast, photoacoustic (PA) imaging, an emerging modality, is capable of deep tissue, noninvasive imaging by combining near-infrared light excitation and ultrasound detection. Here, we show that voltage-dependent quenching of dye fluorescence leads to a reciprocal enhancement of PA intensity. We synthesized a near-infrared photoacoustic VSD (PA-VSD), whose PA intensity change is sensitive to membrane potential. In the polarized state, this cyanine-based probe enhances PA intensity while decreasing fluorescence output in a lipid vesicle membrane model. A theoretical model accounts for how the experimental PA intensity change depends on fluorescence and absorbance properties of the dye. These results not only demonstrate PA voltage sensing but also emphasize the interplay of both fluorescence and absorbance properties in the design of optimized PA probes. Together, our results demonstrate PA sensing as a potential new modality for recording and external imaging of electrophysiological and neurochemical events in the brain.

Listening to membrane potential: photoacoustic voltage-sensitive dye recording

NASA Astrophysics Data System (ADS)

Zhang, Haichong K.; Yan, Ping; Kang, Jeeun; Abou, Diane S.; Le, Hanh N. D.; Jha, Abhinav K.; Thorek, Daniel L. J.; Kang, Jin U.; Rahmim, Arman; Wong, Dean F.; Boctor, Emad M.; Loew, Leslie M.

2017-04-01

Voltage-sensitive dyes (VSDs) are designed to monitor membrane potential by detecting fluorescence changes in response to neuronal or muscle electrical activity. However, fluorescence imaging is limited by depth of penetration and high scattering losses, which leads to low sensitivity in vivo systems for external detection. By contrast, photoacoustic (PA) imaging, an emerging modality, is capable of deep tissue, noninvasive imaging by combining near-infrared light excitation and ultrasound detection. Here, we show that voltage-dependent quenching of dye fluorescence leads to a reciprocal enhancement of PA intensity. We synthesized a near-infrared photoacoustic VSD (PA-VSD), whose PA intensity change is sensitive to membrane potential. In the polarized state, this cyanine-based probe enhances PA intensity while decreasing fluorescence output in a lipid vesicle membrane model. A theoretical model accounts for how the experimental PA intensity change depends on fluorescence and absorbance properties of the dye. These results not only demonstrate PA voltage sensing but also emphasize the interplay of both fluorescence and absorbance properties in the design of optimized PA probes. Together, our results demonstrate PA sensing as a potential new modality for recording and external imaging of electrophysiological and neurochemical events in the brain.

Simultaneous velocity and pressure quantification using pressure-sensitive flow tracers in air

NASA Astrophysics Data System (ADS)

Zhang, Peng; Peterson, Sean; Porfiri, Maurizio

2017-11-01

Particle-based measurement techniques for assessing the velocity field of a fluid have advanced rapidly over the past two decades. Full-field pressure measurement techniques have remained elusive, however. In this work, we aim to demonstrate the possibility of direct simultaneous planar velocity and pressure measurement of a high speed aerodynamic flow by employing novel pressure-sensitive tracer particles for particle image velocimetry (PIV). Specifically, the velocity and pressure variations of an airflow through a converging-diverging channel are studied. Polystyrene microparticles embedded with a pressure-sensitive phosphorescent dye-platinum octaethylporphyrin (PtOEP)-are used as seeding particles. Due to the oxygen quenching effect, the emission lifetime of PtOEP is highly sensitive to the oxygen concentration, that is, the partial pressure of oxygen, in the air. Since the partial pressure of oxygen is linearly proportional to the air pressure, we can determine the air pressure through the phosphorescence emission lifetime of the dye. The velocity field is instead obtained using traditional PIV methods. The particles have a pressure resolution on the order of 1 kPa, which may be improved by optimizing the particle size and dye concentration to suit specific flow scenarios. This work was supported by the National Science Foundation under Grant Number CBET-1332204.

Characteristics of the iodide/triiodide redox mediator in dye-sensitized solar cells.

PubMed

Boschloo, Gerrit; Hagfeldt, Anders

2009-11-17

Dye-sensitized solar cells (DSCs) have gained widespread interest because of their potential for low-cost solar energy conversion. Currently, the certified record efficiency of these solar cells is 11.1%, and measurements of their durability and stability suggest lifetimes exceeding 10 years under operational conditions. The DSC is a photoelectrochemical system: a monolayer of sensitizing dye is adsorbed onto a mesoporous TiO(2) electrode, and the electrode is sandwiched together with a counter electrode. An electrolyte containing a redox couple fills the gap between the electrodes. The redox couple is a key component of the DSC. The reduced part of the couple regenerates the photo-oxidized dye. The formed oxidized species diffuses to the counter electrode, where it is reduced. The photovoltage of the device depends on the redox couple because it sets the electrochemical potential at the counter electrode. The redox couple also affects the electrochemical potential of the TiO(2) electrode through the recombination kinetics between electrons in TiO(2) and oxidized redox species. This Account focuses on the special properties of the iodide/triiodide (I(-)/I(3)(-)) redox couple in dye-sensitized solar cells. It has been the preferred redox couple since the beginning of DSC development and still yields the most stable and efficient DSCs. Overall, the iodide/triiodide couple has good solubility, does not absorb too much light, has a suitable redox potential, and provides rapid dye regeneration. But what distinguishes I(-)/I(3)(-) from most redox mediators is the very slow recombination kinetics between electrons in TiO(2) and the oxidized part of the redox couple, triiodide. Certain dyes adsorbed at TiO(2) catalyze this recombination reaction, presumably by binding iodine or triiodide. The standard potential of the iodide/triiodide redox couple is 0.35 V (versus the normal hydrogen electrode, NHE), and the oxidation potential of the standard DSC-sensitizer (Ru(dcbpy)(2)(NCS)(2)) is 1.1 V. The driving force for reduction of oxidized dye is therefore as large as 0.75 V. This process leads to the largest internal potential loss in DSC devices. We expect that overall efficiencies above 15% might be achieved if half of this internal potential loss could be gained. The regeneration of oxidized dye with iodide leads to the formation of the diiodide radical (I(2)(-*)). The redox potential of the I(2)(-*)/I(-) couple must therefore be considered when determining the actual driving force for dye regeneration. The formed I(2)(-*) disproportionates to I(3)(-) and I(-), which leads to a large loss in potential energy.

The effect of an atomically deposited layer of alumina on NiO in P-type dye-sensitized solar cells.

PubMed

Natu, Gayatri; Huang, Zhongjie; Ji, Zhiqiang; Wu, Yiying

2012-01-10

We present a systematic investigation of the fundamental effects of an atomically deposited alumina (AlO(x)H(y)) onto the NiO films in p-type dye-sensitized solar cells (p-DSCs). With P1 as the sensitizing dye and 0.1 M I(2) and 1.0 M LiI in 3-methoxypropionitrile as the electrolyte, one atomic layer deposition (ALD) cycle of alumina was used to achieve a 74% increase in the overall conversion efficiency of a NiO-based DSC. The open circuit voltage of the cells increased from 0.11 to 0.15 V, and the short circuit current density increased from 0.83 to 0.95 mA/cm(2). Adsorption isotherm studies were performed to show that the amount of dye adsorbed on the NiO-alumina film is slightly lower than the amount adsorbed on the nontreated NiO film. The increased J(sc) was therefore assigned to the increased efficiency of carrier collection at the semiconductor-FTO interface. Our study of the photocurrent onset potentials of NiO and NiO-alumina films with the chopped light measurement technique showed no definitive difference in the onset potential values. However, the DSCs based on NiO-alumina showed a higher recombination resistance value from the electrochemical impedance studies and a higher diode ideality factor from the V(oc) versus ln(light intensity) plots as compared to the DSCs based on untreated NiO. It has thus been established that the increase in V(oc) upon alumina treatment arises due to a higher resistance for electron-hole recombination across NiO surface locally.

A home-made system for IPCE measurement of standard and dye-sensitized solar cells.

PubMed

Palma, Giuseppina; Cozzarini, Luca; Capria, Ennio; Fraleoni-Morgera, Alessandro

2015-01-01

A home-made system for incident photon-to-electron conversion efficiency (IPCE) characterization, based on a double-beam UV-Vis spectrophotometer, has been set up. In addition to its low cost (compared to the commercially available apparatuses), the double-beam configuration gives the advantage to measure, autonomously and with no need for supplementary equipment, the lamp power in real time, compensating possible variations of the spectral emission intensity and quality, thus reducing measurement times. To manage the optical and electronic components of the system, a custom software has been developed. Validations carried out on a common silicon-based photodiode and on a dye-sensitized solar cell confirm the possibility to adopt this system for determining the IPCE of solar cells, including dye-sensitized ones.

Highly water-soluble BODIPY-based fluorescent probe for sensitive and selective detection of nitric oxide in living cells.

PubMed

Vegesna, Giri K; Sripathi, Srinivas R; Zhang, Jingtuo; Zhu, Shilei; He, Weilue; Luo, Fen-Tair; Jahng, Wan Jin; Frost, Megan; Liu, Haiying

2013-05-22

A highly water-soluble BODIPY dye bearing electron-rich o-diaminophenyl groups at 2,6-positions was prepared as a highly sensitive and selective fluorescent probe for detection of nitric oxide (NO) in living cells. The fluorescent probe displays an extremely weak fluorescence with fluorescence quantum yield of 0.001 in 10 mM phosphate buffer (pH 7.0) in the absence of NO as two electron-rich o-diaminophenyl groups at 2,6-positions significantly quench the fluorescence of the BODIPY dye via photoinduced electron transfer mechanism. The presence of NO in cells enhances the dye fluorescence dramatically. The fluorescent probe demonstrates excellent water solubility, membrane permeability, and compatibility with living cells for sensitive detection of NO.

Sensitization of photoprocesses in colloidal Ag2S quantum dots by dye molecules

NASA Astrophysics Data System (ADS)

Ovchinnikov, Oleg V.; Kondratenko, Tamara S.; Grevtseva, Irina G.; Smirnov, Mikhail S.; Pokutnyi, Sergey I.

2016-07-01

The effect of photosensitization of IR luminescence excitation (1205 nm) of colloidal Ag2S quantum dots (QDs) with average size of 2.5±0.6 nm in gelatin at 600 to 660 nm by molecules of 3,3'-di-(γ-sulfopropyl)-4,4',5,5'-dibenzo-9-ethylthiacarbocyanine betaine pyridinium salt (Dye1) and thionine dye (Dye2) was registered. Cis-J-aggregates of Dye1 and cations monomer of Dye2 conjugated with Ag2S QDs take part in this process. The photosensitization of luminescence excitation of colloidal Ag2S QDs was interpreted by resonance nonradiation transfer of electronic excitation energy from cis-J-aggregates of Dye1 and cations of Dye2 to centers of recombination luminescence of Ag2S QDs.

Fluorescein: a Photo-CIDNP Sensitizer Enabling Hyper-Sensitive NMR Data Collection in Liquids at Low Micromolar Concentration

PubMed Central

Okuno, Yusuke; Cavagnero, Silvia

2016-01-01

Photochemically induced dynamic nuclear polarization (photo-CIDNP) is a powerful approach for sensitivity enhancement in NMR spectroscopy. In liquids, inter-molecular photo-CIDNP depends on the transient bimolecular reaction between photoexcited dye and sample of interest. Hence the extent of polarization is sample-concentration dependent. This study introduces fluorescein (FL) as a photo-CIDNP dye whose performance is exquisitely tailored to data collection at extremely low sample concentrations. The photo-CIDNP resonance intensities of tryptophan in the presence of either FL or FMN (i.e., the routinely employed flavin mononucleotide photosensitizer) in the liquid state show that FL yields superior sensitivity and enables rapid data collection down to an unprecedented 1 micromolar concentration. This result was achieved on a conventional spectrometer operating at 14.1 Tesla, and equipped with a room-temperature probe (i.e., non-cryogenic). Kinetic simulations show that the excellent behavior of FL arises from its long excited-state triplet lifetime and superior photostability relative to conventional photo-CIDNP sensitizers. PMID:26744790

Synthesis of SnO_2 nanoparticles by electrooxidation of tin in quaternary ammonium salt for application in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Abrari, Masoud; Ghanaatshoar, Majid; Hosseiny Davarani, Saied Saeed; Moazami, Hamid Reza; Kazeminezhad, Iraj

2017-05-01

A facile synthetic route has been employed to prepare tin oxide nanoparticles. The route comprises anodic dissolution of metallic tin in the presence of tetramethylammonium chloride called electrooxidation. The effect of experimental parameters was investigated with special focus on solution pH. The obtained nanostructures have been characterized by XRD, EDS, TEM, FESEM, FTIR and UV-visible studies. The results show that the solution pH has a critical influence on the nanoparticles properties. The hydrophilic feature of nanoparticles decreases with pH growth, whereas their mean size increases. On the other hand, the size distribution is much uniform for the samples prepared at low pH. Having achieved the nanoparticles by electrooxidation, the dye-sensitized solar cells based on the produced SnO_2 nanoparticles were fabricated and the influence of nanoparticles on their performance was investigated. By variation in solution pH, we prepared nanoparticles with different particle sizes and photoanodes with various dye-loading abilities. The dye absorption and consequently current density of cells increased in acidic case, and therefore, power conversion efficiency grew up by 33% in acidic synthetic environment.

Organic solar cells and physics education

NASA Astrophysics Data System (ADS)

Csernovszky, Zoltán; Horváth, Ákos

2018-07-01

This paper explains the operational principles of a home-made organic solar cell with the representation of an electron-cycle on an energy-level diagram. We present test data for a home-made organic solar cell which operates as a galvanic cell and current source in an electrical circuit. To determine the maximum power of the cell, the optimal current was estimated with a linear approximation. Using different light sources and dyes, the electrical properties of organic solar cells were compared. The solar cells were studied by looking at spectrophotometric data from different sensitizer dyes, generated by a do-it-yourself diffraction grating spectroscope. The sensitizer dyes of solar cells were tested by the diffraction grating spectroscope. The data were analysed on a light-intensity‑wavelength diagram to discover which photons were absorbed and to understand the colours of the fruits containing these dyes. In terms of theoretical applications, the paper underlines the analogous nature of organic solar cells, a conventional single p‑n junction solar cell and the light-dependent reactions of photosynthesis, using energy-level diagrams of electron-cycles. To conclude, a classification of photon‑electron interactions in molecular systems and crystal lattices is offered, to show the importance of organic solar cells.

Performance optimization of dye-sensitized solar cells by multilayer gradient scattering architecture of TiO2 microspheres.

PubMed

Li, Mingyue; Li, Meiya; Liu, Xiaolian; Bai, Lihua; Luoshan, Mengdai; Lei, Wen; Wang, Zhen; Zhu, Yongdan; Zhao, Xingzhong

2017-01-20

TiO 2 microspheres (TMSs) with unique hierarchical structure and unusual high specific surface area are synthesized and incorporated into a photoanode in various TMS multilayer gradient architectures to form novel photoanodes and dye-sensitized solar cells (DSSCs). Significant influences of these architectures on the photoelectric properties of DSSCs are obtained. The DSSC with the optimal TMS gradient-ascent architecture of M036 has the largest amounts of dye absorption, strongest light absorption, longest electron lifetime and lowest electron recombination, and thus exhibits the maximum short circuit current density (J sc ) of 16.49 mA cm -2 and photoelectric conversion efficiency (η) of 7.01%, notably higher than those of conventional DSSCs by 21% and 22%, respectively. These notable improvements in the properties of DSSCs can be attributed to the TMS gradient-ascent architecture of M036 which can most effectively increase dye absorption and localize incident light within the photoanode by the light scattering of TMSs, and thus utilize the incident light thoroughly. This study provides an optimized and universal configuration for the scattering microspheres incorporated in the hybrid photoanode, which can significantly improve the performance of DSSCs.

Photovoltaic characteristics of natural light harvesting dye sensitized solar cells.

PubMed

Hafez, H S; Shenouda, S S; Fadel, M

2018-03-05

In this work of research, anthocyanin as a natural dye obtained from raspberry fruits, was used and tested as a photon harvesting/electron donating dye in titanium dioxide nanoparticle-based DSSCs. A working photoelectrode made from TiO 2 nanoparticles with an average particle size (10-40nm) that is coated on Florine doped tin-oxide substrate, was prepared via a simple and low cost hydrothermal method. A detailed structural and morphological analysis of the TiO 2 photoactive electrode was investigated by X-ray diffraction (XRD), diffuse reflectance spectrometer, transmission electron microscope (TEM) and scanning electron microscope (SEM). Complete photovoltaic characteristics including (current, voltage, outpower, and responsivity) of the natural anthocyanin based dye sensitized solar cell have been investigated under different illumination intensity ranging from 10 to 100mW.cm -2 . The cell responsivity and efficiency of the fabricated solar cell under different illumination intensity were found to be in the range (R=15.6-23.8mA.W -1 and η=0.13-0.25) at AM=1.5 conditions. This study is important for enhancing the future applications of the promising DSSC technology. Copyright © 2017 Elsevier B.V. All rights reserved.

Redefining Molecular Amphipathicity in Reversing the "Coffee-Ring Effect": Implications for Single Base Mutation Detection.

PubMed

Huang, Chi; Wang, Jie; Lv, Xiaobo; Liu, Liu; Liang, Ling; Hu, Wei; Luo, Changliang; Wang, Fubing; Yuan, Quan

2018-05-21

The "coffee ring effect" is a natural phenomenon where sessile drops leave ring-shaped structures on solid surfaces upon drying. It drives non-uniform deposition of suspended compounds on substrates, which adversely affects many processes, including surface-assisted biosensing and molecular self-assembly. In this study, we describe how the coffee ring effect can be eliminated by controlling the amphipathicity of the suspended compounds, for example DNA modified with hydrophobic dye. Specifically, nuclease digestion of the hydrophilic DNA end converts the dye-labeled molecule into an amphipathic molecule (one with comparably weighted hydrophobic and hydrophilic ends) and reverses the coffee ring effect and results in uniform disc-shaped feature deposition of the dye. The amphipathic product decreases the surface tension of the sessile drops and induces Marangoni flow, which drives the uniform distribution of the amphipathic dye-labeled product in the drops. As proof-of-concept, this strategy was used in a novel enzymatic amplification method for biosensing to eliminate the coffee ring effect on a nitrocellulose membrane and increase assay reliability and sensitivity. Importantly, the reported strategy for eliminating the coffee ring effect can be extended to other sessile drop systems for potentially improving assay reliability, and sensitivity.

Target-specific nanoparticles containing a broad band emissive NIR dye for the sensitive detection and characterization of tumor development.

PubMed

Behnke, Thomas; Mathejczyk, Julia E; Brehm, Robert; Würth, Christian; Gomes, Fernanda Ramos; Dullin, Christian; Napp, Joanna; Alves, Frauke; Resch-Genger, Ute

2013-01-01

Current optical probes including engineered nanoparticles (NPs) are constructed from near infrared (NIR)-emissive organic dyes with narrow absorption and emission bands and small Stokes shifts prone to aggregation-induced self-quenching. Here, we present the new asymmetric cyanine Itrybe with broad, almost environment-insensitive absorption and emission bands in the diagnostic window, offering a unique flexibility of the choice of excitation and detection wavelengths compared to common NIR dyes. This strongly emissive dye was spectroscopically studied in different solvents and encapsulated into differently sized (15, 25, 100 nm) amino-modified polystyrene NPs (PSNPs) via a one-step staining procedure. As proof-of-concept for its potential for pre-/clinical imaging applications, Itrybe-loaded NPs were surface-functionalized with polyethylene glycol (PEG) and the tumor-targeting antibody Herceptin and their binding specificity to the tumor-specific biomarker HER2 was systematically assessed. Itrybe-loaded NPs display strong fluorescence signals in vitro and in vivo and Herceptin-conjugated NPs bind specifically to HER2 as demonstrated in immunoassays as well as on tumor cells and sections from mouse tumor xenografts in vitro. This demonstrates that our design strategy exploiting broad band-absorbing and -emitting dyes yields versatile and bright NIR probes with a high potential for e.g. the sensitive detection and characterization of tumor development and progression. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mild extraction methods using aqueous glucose solution for the analysis of natural dyes in textile artefacts dyed with Dyer's madder (Rubia tinctorum L.).

PubMed

Ford, Lauren; Henderson, Robert L; Rayner, Christopher M; Blackburn, Richard S

2017-03-03

Madder (Rubia tinctorum L.) has been widely used as a red dye throughout history. Acid-sensitive colorants present in madder, such as glycosides (lucidin primeveroside, ruberythric acid, galiosin) and sensitive aglycons (lucidin), are degraded in the textile back extraction process; in previous literature these sensitive molecules are either absent or present in only low concentrations due to the use of acid in typical textile back extraction processes. Anthraquinone aglycons alizarin and purpurin are usually identified in analysis following harsh back extraction methods, such those using solvent mixtures with concentrated hydrochloric acid at high temperatures. Use of softer extraction techniques potentially allows for dye components present in madder to be extracted without degradation, which can potentially provide more information about the original dye profile, which varies significantly between madder varieties, species and dyeing technique. Herein, a softer extraction method involving aqueous glucose solution was developed and compared to other back extraction techniques on wool dyed with root extract from different varieties of Rubia tinctorum. Efficiencies of the extraction methods were analysed by HPLC coupled with diode array detection. Acidic literature methods were evaluated and they generally caused hydrolysis and degradation of the dye components, with alizarin, lucidin, and purpurin being the main compounds extracted. In contrast, extraction in aqueous glucose solution provides a highly effective method for extraction of madder dyed wool and is shown to efficiently extract lucidin primeveroside and ruberythric acid without causing hydrolysis and also extract aglycons that are present due to hydrolysis during processing of the plant material. Glucose solution is a favourable extraction medium due to its ability to form extensive hydrogen bonding with glycosides present in madder, and displace them from the fibre. This new glucose method offers an efficient process that preserves these sensitive molecules and is a step-change in analysis of madder dyed textiles as it can provide further information about historical dye preparation and dyeing processes that current methods cannot. The method also efficiently extracts glycosides in artificially aged samples, making it applicable for museum textile artefacts. Copyright © 2017 Elsevier B.V. All rights reserved.

Properties of electronically excited states of four squaraine dyes and their complexes with fullerene C70: A theoretical investigation

NASA Astrophysics Data System (ADS)

Zhang, Jian; Li, Tingyu

2017-09-01

Solar cells sensitized by polypyridyl Ru(II) complexes exhibit relatively high efficiency, however those photo-sensitizers did not absorb the photons in the far-red and near-infrared region. At present, squaraine dyes have received considerable attention as their attractively intrinsic red light absorption and unusual high molar extinction coefficient. Here we applied density functional theory and time dependent density functional theory to investigate the properties of electronically excited states of four squaraine dyes and their complexes with fullerene C70. The influences of different functionals, basis sets and solvent effects are evaluated. To understand the photophysical properties, the investigations are basing on a classification method which splits the squaraine dyes and their complexes with fullerene C70 into two units to characterize the intramolecular density distribution. We present the signatures of their electronically excited states which are characterized as local excitation or charge-transfer excitation. The relationship between open-circuit voltage and the number of intramolecular hydrogen bonds in squaraine dyes are discussed.

Application of sulphanilamides disazo dyes with Tropaeolin O for simple, rapid and sensitive spectrophotometric assay of medicines.

PubMed

Boiko, Maria; Vrublevska, Teodoziya; Korkuna, Olha; Teslyar, Grigory

2011-07-01

A rapid, simple and sensitive spectrophotometric method for the determination of some sulphanilamides is described. The method is based on the formation of blue coloured disazo dyes by the diazotization of sulphonamides viz. sulphanilamide (SA), sulphamerazine (SMR), sulphamethazine (SMZ), sulphadimethoxine (SDM), sulphamethoxazole (SMX), sulphadiazine (SDA), sulfathiazole (STZ), sulphaguanidine (SGN), sulphamonomethoxine (SMM), sulphamethoxypyridazine (SMP) in 0.5M hydrochloric acid media at ice bath followed by the azocoupling reaction with acid monoazo dye Tropaeolin O (TrO) at pH=10.5. Formed products are stable for 10h at room temperature. Effective molar absorptivities at absorbance maxima 595nm for disazo dyes were ∼10(4)M(-1)cm(-1). Stoichiometric ratios of the components of disazo dyes were determined by means of mole ratio and continuous variations methods. Linear ranges for sulphanilamides determination were 0.4-14.0μgml(-1). The methods were successfully approved at suphanilamides determination in model solutions and commercial pharmaceutical preparations. Copyright © 2011 Elsevier B.V. All rights reserved.

Method and apparatus for passive optical dosimeter comprising caged dye molecules

DOEpatents

Sandison, David R.

2001-07-03

A new class of ultraviolet dosimeters is made possible by exposing caged dye molecules, which generate a dye molecule on exposure to ultraviolet radiation, to an exterior environment. Applications include sunburn monitors, characterizing the UV exposure history of UV-sensitive materials, especially including structural plastics, and use in disposable `one-use` optical equipment, especially medical devices.

Calcium Sensitive Fluorescent Dyes Fluo-4 and Fura Red under Pressure: Behaviour of Fluorescence and Buffer Properties under Hydrostatic Pressures up to 200 MPa.

PubMed

Schneidereit, D; Vass, H; Reischl, B; Allen, R J; Friedrich, O

2016-01-01

The fluorescent Ca2+ sensitive dyes Fura Red (ratiometric) and Fluo-4 (non-ratiometric) are widely utilized for the optical assessment of Ca2+ fluctuations in vitro as well as in situ. The fluorescent behavior of these dyes is strongly depends on temperature, pH, ionic strength and pressure. It is crucial to understand the response of these dyes to pressure when applying calcium imaging technologies in the field of high pressure bioscience. Therefore, we use an optically accessible pressure vessel to pressurize physiological Ca2+-buffered solutions at different fixed concentrations of free Ca2+ (1 nM to 25.6 μM) and a specified dye concentration (12 μM) to pressures of 200 MPa, and record dye fluorescence intensity. Our results show that Fluo-4 fluorescence intensity is reduced by 31% per 100 MPa, the intensity of Fura Red is reduced by 10% per 100 MPa. The mean reaction volume for the dissociation of calcium from the dye molecules [Formula: see text] is determined to -17.8 ml mol-1 for Fluo-4 and -21.3 ml mol-1 for Fura Red. Additionally, a model is presented that is used to correct for pressure-dependent changes in pH and binding affinity of Ca2+ to EGTA, as well as to determine the influence of these changes on dye fluorescence.

pH-sensitive optrode

DOEpatents

Hirschfeld, Tomas B.; Wang, Francis T.

1989-01-01

An apparatus is provided for remotely monitoring pH. A support material is provided on which organic dye molecules are covalently attached at a surface density falling within a predetermined range. The pH dependent fluorescence response of the bound organic dye molecules depends critically on surface density of the organic dye molecules bound to the support material and the nature of the covalent linkage betwen the organic dye molecules and the support material. The invention is operated by contacting the support material on which the organic dye is attached with the fluid whose pH is to be determined. When in contact, the organic dye on the support material is illuminated so that it is caused to fluoresce. The intensity of organic dye fluorescence is then related to pH.

Synchronization analysis of voltage-sensitive dye imaging during focal seizures in the rat neocortex

NASA Astrophysics Data System (ADS)

Takeshita, Daisuke; Bahar, Sonya

2011-12-01

Seizures are often assumed to result from an excess of synchronized neural activity. However, various recent studies have suggested that this is not necessarily the case. We investigate synchronization during focal neocortical seizures induced by injection of 4-aminopyridine (4AP) in the rat neocortex in vivo. Neocortical activity is monitored by field potential recording and by the fluorescence of the voltage-sensitive dye RH-1691. After removal of artifacts, the voltage-sensitive dye (VSD) signal is analyzed using the nonlinear dynamics-based technique of stochastic phase synchronization in order to determine the degree of synchronization within the neocortex during the development and spread of each seizure event. Results show a large, statistically significant increase in synchronization during seizure activity. Synchrony is typically greater between closer pixel pairs during a seizure event; the entire seizure region is synchronized almost exactly in phase. This study represents, to our knowledge, the first application of synchronization analysis methods to mammalian VSD imaging in vivo. Our observations indicate a clear increase in synchronization in this model of focal neocortical seizures across a large area of the neocortex; a sharp increase in synchronization during seizure events was observed in all 37 seizures imaged. The results are consistent with a recent computational study which simulates the effect of 4AP in a neocortical neuron model.

Pyrene based D-π-A architectures: synthesis, density functional theory, photophysics and electron transfer dynamics.

PubMed

Kathiravan, Arunkumar; Srinivasan, Venkatesan; Khamrang, Themmila; Velusamy, Marappan; Jaccob, Madhavan; Pavithra, Nagaraj; Anandan, Sambandam; Velappan, Kandavelu

2017-01-25

Pyrene derivatives show immense potential as sensitizers for dye-sensitized solar cells (DSCs). Therefore, this work focuses on the impact of π-spacers on the photophysical, electrochemical and photovoltaic properties of pyrene based D-π-A dyes, since the insertion of π-spacers is one of the doable strategies to improve the light harvesting properties of the dye. In this respect, three new pyrene based D-π-A dyes have been synthesized and characterized by 1 H, 13 C NMR, and elemental analyses and EI-MS spectrometry. The selected π-spacers are benzene, thiophene and furan. Compared with a benzene spacer, the introduction of a heterocyclic ring spacer reduces the band gap of the dye and brings about the broadening of the absorption spectra to the longer wavelength region through intramolecular charge-transfer (ICT). Combined experimental and theoretical studies were performed to investigate the ICT process involved in the pyrene derivatives. The profound solvatochromism with increased nonradiative rate constants (k nr ) has been construed in terms of ICT from the pyrene core to rhodanine-3-acetic acid via conjugated π-spacers. Electrochemical data also reveal that the HOMO and LUMO energy levels are fine-tuned by incorporating different π-spacers between pyrene and rhodanine-3-acetic acid. On the basis of the optimized DSC test conditions, the best performance was found for PBRA, in which a benzene group is the conjugated π-spacer. The divergence in the photovoltaic behaviors of these dyes was further explicated by femtosecond fluorescence and electrochemical impedance spectroscopy.

Ultra-Wideband Multi-Dye-Sensitized Upconverting Nanoparticles for Information Security Application.

PubMed

Lee, Jongha; Yoo, Byeongjun; Lee, Hakyong; Cha, Gi Doo; Lee, Hee-Su; Cho, Youngho; Kim, Sang Yeon; Seo, Hyunseon; Lee, Woongchan; Son, Donghee; Kang, Myungjoo; Kim, Hyung Min; Park, Yong Il; Hyeon, Taeghwan; Kim, Dae-Hyeong

2017-01-01

Multi-dye-sensitized upconverting nanoparticles (UCNPs), which harvest photons of wide wavelength range (450-975 nm) are designed and synthesized. The UCNPs embedded in a photo-acid generating layer are integrated on destructible nonvolatile resistive memory device. Upon illumination of light, the system permanently erases stored data, achieving enhanced information security. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantification of pressure sensitive adhesive, residual ink, and other colored process contaminants using dye and color image analysis

Treesearch

Roy R. Rosenberger; Carl J. Houtman

2000-01-01

The USPS Image Analysis (IA) protocol recommends the use of hydrophobic dyes to develop contrast between pressure sensitive adhesive (PSA) particles and cellulosic fibers before using a dirt counter to detect all contaminants that have contrast with the handsheet background. Unless the sample contains no contaminants other than those of interest, two measurement steps...

Direct synthesis of platelet graphitic-nanofibres as a highly porous counter-electrode in dye-sensitized solar cells.

PubMed

Hsieh, Chien-Kuo; Tsai, Ming-Chi; Yen, Ming-Yu; Su, Ching-Yuan; Chen, Kuei-Fu; Ma, Chen-Chi M; Chen, Fu-Rong; Tsai, Chuen-Horng

2012-03-28

We synthesized platelet graphitic-nanofibres (GNFs) directly onto FTO glass and applied this forest of platelet GNFs as a highly porous structural counter-electrode in dye-sensitized solar cells (DSSCs). We investigated the electrochemical properties of counter-electrodes made from the highly porous structural GNFs and the photoconversion performance of the cells made with these electrodes.

Molecular modification of coumarin dyes for more efficient dye sensitized solar cells

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

Sanchez-de-Armas, Rocio; San-Miguel, Miguel A.; Oviedo, Jaime

2012-05-21

In this work, new coumarin based dyes for dye sensitized solar cells (DSSC) have been designed by introducing several substituent groups in different positions of the NKX-2311 structure. Two types of substitutions have been considered: the introduction of three electron-donating groups (-OH, -NH{sub 2}, and -OCH{sub 3}) and two different substituents with steric effect: -CH{sub 2}-CH{sub 2}-CH{sub 2}- and -CH{sub 2}-HC=CH-. The electronic absorption spectra (position and width of the first band and absorption threshold) and the position of the LUMO level related to the conduction band have been used as theoretical criteria to evaluate the efficiency of the newmore » dyes. The introduction of a -NH{sub 2} group produces a redshift of the absorption maximum position and the absorption threshold, which could improve the cell efficiency. In contrast, the introduction of -CH{sub 2}-CH{sub 2}-CH{sub 2}- does not modify significantly the electronic structure of NKX-2311, but it might prevent aggregation. Finally, -CH{sub 2}-HC=CH- produces important changes both in the electronic spectrum and in the electronic structure of the dye, and it would be expected as an improvement of cell efficiency for these dyes.« less

The influence of material type and composition of TiO2- ZnO on manufacturing of paste for the application of DSSC

NASA Astrophysics Data System (ADS)

Retnaningsih, L.; Muliani, L.; Aggraini, P. N.; Hidayat, J.

2016-11-01

Research, fabrication and material selection for the application of Dye- sensitized solar cell (DSSC) has been performed on glass FTO (Flour Tin Oxide). The material is used in the form of TiO2 paste, TiO2 powder and ZnO powder. Dye-sensitized solar cell (DSSC), is a fotoelektrokimia-based solar cells where the absorption process light done by the dye molecules and the process of separation of inorganic semiconductor materials by charge of Titanium dioxide (TiO2) and Zinc oxide (ZnO). The purpose of this research is to know the exact composition of TiO2 and ZnO materials in order to produce the best efficiency with DSSC. On this research was done making prototype dye-sensitized solar cell using dye Z 907, and semiconductor nanoparticles TiO2 and ZnO powder that is made into a paste by mixing different composition in two variations of samples: A = ZnO (powder) + 40% TiO2 (powder) and B = 60% TiO2 (powder) (40%) + TiO2 (pasta) 60%. The second variation of this high efficiency is value at sample B i.e. TiO2 (powder) + 40% TiO2 (paste) of 60%.

Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture.

PubMed

Klein, M; Pankiewicz, R; Zalas, M; Stampor, W

2016-07-21

The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism.

Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture

NASA Astrophysics Data System (ADS)

Klein, M.; Pankiewicz, R.; Zalas, M.; Stampor, W.

2016-07-01

The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism.

Efficient dye-sensitized solar cells from mesoporous zinc oxide nanostructures sensitized by N719 dye

NASA Astrophysics Data System (ADS)

Kumara, G. R. A.; Deshapriya, U.; Ranasinghe, C. S. K.; Jayaweera, E. N.; Rajapakse, R. M. G.

2018-03-01

Dye-sensitized solar cells (DSCs) have attracted a great deal of attention due to their low-cost and high power conversion efficiencies. They usually utilize an interconnected nanoparticle layer of TiO2 as the electron transport medium. From the fundamental point of view, faster mobility of electrons in ZnO is expected to contribute to better performance in DSCs than TiO2, though the actual practical situation is quite the opposite. In this research, we addressed this problem by first applying a dense layer of ZnO on FTO followed by a mesoporous layer of interconnected ZnO nanoparticle layer, both were prepared by spray pyrolysis technique. The best cell shows a power conversion efficiency of 5.2% when the mesoporous layer thickness is 14 μm and the concentration of the N719 dye in dye coating solution is 0.3 mM, while a cell without a dense layer shows 4.2% under identical conditions. The surface concentration of dye adsorbed in the cell with a dense layer and that without a dense layer are 5.00 × 10‑7 and 3.34 × 10‑7 mol/cm2, respectively. The cell with the dense layer has an electron lifetime of 54.81 ms whereas that without the dense layer is 11.08 ms. As such, the presence of the dense layer improves DSC characteristics of ZnO-based DSCs.

Thiourea incorporated poly(ethylene oxide) as transparent gel polymer electrolyte for dye sensitized solar cell applications

NASA Astrophysics Data System (ADS)

Pavithra, Nagaraj; Velayutham, David; Sorrentino, Andrea; Anandan, Sambandam

2017-06-01

A new series of transparent gel polymer electrolytes are prepared by adding various weight percent of thiourea coupled with poly(ethylene oxide) for the application of dye-sensitized solar cells. Coupling of thiourea in the presence of iodine undergoes dimerization reaction to produce formamidine disulfide. Fourier Transform Infrared spectroscopy shows that the interactions of thiourea and formamidine disulfide with electronegative ether linkage of poly(ethylene oxide) results in conformational changes of gel polymer electrolytes. Electrochemical impedance spectroscopy and linear sweep voltammetry experiments reveal an increment in ionic conductivity and tri-iodide diffusion coefficient, for thiourea modified gel polymer electrolytes. Finally, the prepared electrolytes are used as a redox mediator in dye-sensitized solar cells and the photovoltaic properties were studied. Apart from transparency, the gel polymer electrolytes with thiorurea show higher photovoltaic properties compared to bare gel polymer electrolyte and a maximum photocurrent efficiency of 7.17% is achieved for gel polymer electrolyte containing 1 wt% of thiourea with a short circuit current of 11.79 mA cm-2 and open circuit voltage of 834 mV. Finally, under rear illumination, almost 90% efficiency is retained upon compared to front illumination.

A ``plasmonic cuvette'': dye chemistry coupled to plasmonic interferometry for glucose sensing

NASA Astrophysics Data System (ADS)

Siu, Vince S.; Feng, Jing; Flanigan, Patrick W.; Palmore, G. Tayhas R.; Pacifici, Domenico

2014-06-01

A non-invasive method for the detection of glucose is sought by millions of diabetic patients to improve personal management of blood glucose over a lifetime. In this work, the synergistic advantage of combining plasmonic interferometry with an enzyme-driven dye assay yields an optical sensor capable of detecting glucose in saliva with high sensitivity and selectivity. The sensor, coined a "plasmonic cuvette," is built around a nano-scale groove-slit-groove (GSG) plasmonic interferometer coupled to an Amplex-red/Glucose-oxidase/Glucose (AR/GOx/Glucose) assay. The proposed device is highly sensitive, with a measured intensity change of 1.7×105%/m (i.e., one order of magnitude more sensitive than without assay) and highly specific for glucose sensing in picoliter volumes, across the physiological range of glucose concentrations found in human saliva (20-240 μm). Real-time glucose monitoring in saliva is achieved by performing a detailed study of the underlying enzyme-driven reactions to determine and tune the effective rate constants in order to reduce the overall assay reaction time to ˜2 min. The results reported suggest that by opportunely choosing the appropriate dye chemistry, a plasmonic cuvette can be turned into a general, real-time sensing scheme for detection of any molecular target, with high sensitivity and selectivity, within extremely low volumes of biological fluid (down to femtoliters). Hereby, we present the results on glucose detection in artificial saliva as a notable and clinically relevant case study.

Optical determination of charge transfer times from indoline dyes to ZnO in solid state dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Meyenburg, I.; Hofeditz, N.; Ruess, R.; Rudolph, M.; Schlettwein, D.; Heimbrodt, W.

2018-05-01

We studied the electron transfer at the interface of organic-inorganic hybrids consisting of indoline derivatives (D149 and D131) on ZnO substrates using a new optical method. We revealed the electron transfer times from the excited dye, e.g. the excitons formed in the dye aggregates to the ZnO substrate by analyzing the photoluminescence transients of the excitons after femtosecond excitation and applying kinetic model calculations. We reveal the changes of the electron transfer times by applying electrical bias. Pushing the Fermi energy of the ZnO substrate towards the excited dye level the transfer time gets longer and eventually the electron transfer is suppressed. The level alignment between the excited dye state and the ZnO Fermi-level is estimated. The excited state of D131 is about 100 meV higher than the respective state of D149 compared to the ZnO conduction band. This leads to shorter electron transfer times and eventually to higher quantum efficiencies of the solar cells.

Effect of nuclear vibrations, temperature, and orientation on injection and recombination conditions in amino-phenyl acid dyes on TiO2

NASA Astrophysics Data System (ADS)

Manzhos, Sergei; Segawa, Hiroshi; Yamashita, Koichi

2012-06-01

Adsorption geometry, nuclear vibrations, and molecular orientation of the dye with respect to the oxide surface affect significantly the performance of dye-sensitized solar cells. We compute the influence of these factors on injection and recombination conditions in organic amino-phenyl acid dyes differing by the donor group on the anatase (101) surface of titania. Nuclear motions affect significantly and differently between the dyes the driving force to injection Δ G. A temperature increase from 300 to 350 K does not have a noticeable effect on the distribution of injection rates in all studied system. Molecular dynamics simulations predict configurations in which dyes tend to lay flat on the oxide surface. The resulting proximity of the oxidation equivalent hole to the oxide is expected to promote recombination. Temporal evolution of the driving force to injection is found to be independent of dye orientation and uncorrelated to the oscillations of the Odye Ti bonds through which the dye is attached to the surface. We conclude that the dynamics of Δ G(t) is explained by uncorrelated evolution of the energies of the dye excited state and of the conduction band minimum of the oxide due to their respective vibrations. This suggests that it must be possible to control independently conditions of recombination (e.g. by preventing the dye oxidation hole from approaching TiO2 by using co-adsorbates) and of injection (e.g. by designing dyes where non-equilibrium geometries strongly destabilize dye's LUMO to increase Δ G).

Occurrence and risk assessment of an azo dye - The case of Disperse Red 1.

PubMed

Vacchi, Francine Inforçato; Von der Ohe, Peter Carsten; Albuquerque, Anjaína Fernandes de; Vendemiatti, Josiane Aparecida de Souza; Azevedo, Carina Cristina Jesus; Honório, Jaqueline Gonçalves; Silva, Bianca Ferreira da; Zanoni, Maria Valnice Boldrin; Henry, Theodore B; Nogueira, Antonio J; Umbuzeiro, Gisela de Aragão

2016-08-01

Water quality criteria to protect aquatic life are not available for most disperse dyes which are often used as commercial mixtures in textile coloration. In this study, the acute and chronic toxicity of the commercial dye Disperse Red 1 (DR1) to eight aquatic organisms from four trophic levels was evaluated. A safety threshold, i.e. Predicted No-Effect Concentration (PNEC), was derived based on the toxicity information of the commercial product and the purified dye. This approach was possible because the toxicity of DR1 was accounting for most of the toxicity of the commercial mixture. A long-term PNEC of 60 ng L(-1) was proposed, based on the most sensitive chronic endpoint for Daphnia similis. A short-term PNEC of 1800 ng L(-1) was proposed based on the most sensitive acute endpoint also for Daphnia similis. Both key studies have been evaluated with the new "Criteria for Reporting and Evaluating ecotoxicity Data" (CRED) methodology, applying more objective criteria to assess the quality of toxicity tests, resulting in two reliable and relevant endpoints with only minor restrictions. HPLC-MS/MS was used to quantify the occurrence of DR1 in river waters of three sites, influenced by textile industry discharges, resulting in a concentration range of 50-500 ng L(-1). The risk quotients for DR1 obtained in this work suggest that this dye can pose a potential risk to freshwater biota. To reduce uncertainty of the derived PNEC, a fish partial or full lifecycle study should be performed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Photoswitchable non-fluorescent thermochromic dye-nanoparticle hybrid probes

PubMed Central

Harrington, Walter N.; Haji, Mwafaq R.; Galanzha, Ekaterina I.; Nedosekin, Dmitry A.; Nima, Zeid A.; Watanabe, Fumiya; Ghosh, Anindya; Biris, Alexandru S.; Zharov, Vladimir P.

2016-01-01

Photoswitchable fluorescent proteins with controllable light–dark states and spectral shifts in emission in response to light have led to breakthroughs in the study of cell biology. Nevertheless, conventional photoswitching is not applicable for weakly fluorescent proteins and requires UV light with low depth penetration in bio-tissue. Here we introduce a novel concept of photoswitchable hybrid probes consisting of thermochromic dye and absorbing nanoparticles, in which temperature-sensitive light–dark states and spectral shifts in absorption can be switched through controllable photothermal heating of doped nanoparticles. The proof-of-concept is demonstrated through the use of two different types of temperature-sensitive dyes doped with magnetic nanoparticles and reversibly photoswitched by a near-infrared laser. Photoacoustic imaging revealed the high contrast of these probes, which is sufficient for their visualization in cells and deep tissue. Our results suggest that these new photoswitchable multicolour probes can be used for multimodal cellular diagnostics and potentially for magnetic and photothermal therapy. PMID:27824110

Interfacial charge separation and photovoltaic efficiency in Fe(ii)-carbene sensitized solar cells.

PubMed

Pastore, Mariachiara; Duchanois, Thibaut; Liu, Li; Monari, Antonio; Assfeld, Xavier; Haacke, Stefan; Gros, Philippe C

2016-10-12

The first combined theoretical and photovoltaic characterization of both homoleptic and heteroleptic Fe(ii)-carbene sensitized photoanodes in working dye sensitized solar cells (DSSCs) has been performed. Three new heteroleptic Fe(ii)-NHC dye sensitizers have been synthesized, characterized and tested. Despite an improved interfacial charge separation in comparison to the homoleptic compounds, the heteroleptic complexes did not show boosted photovoltaic performances. The ab initio quantitative analysis of the interfacial electron and hole transfers and the measured photovoltaic data clearly evidenced fast recombination reactions for heteroleptics, even associated with un unfavorable directional electron flow, and hence slower injection rates, in the case of homoleptics. Notably, quantum mechanics calculations revealed that deprotonation of the not anchored carboxylic function in the homoleptic complex can effectively accelerate the electron injection rate and completely suppress the electron recombination to the oxidized dye. This result suggests that introduction of strong electron-donating substituents on the not-anchored carbene ligand in heteroleptic complexes, in such a way of mimicking the electronic effects of the carboxylate functionality, should yield markedly improved interfacial charge generation properties. The present results, providing for the first time a detailed understanding of the interfacial electron transfers and photovoltaic characterization in Fe(ii)-carbene sensitized solar cells, open the way to a rational molecular engineering of efficient iron-based dyes for photoelectrochemical applications.

A stereo-compound hybrid microscope for combined intracellular and optical recording of invertebrate neural network activity

PubMed Central

Frost, William N.; Wang, Jean; Brandon, Christopher J.

2007-01-01

Optical recording studies of invertebrate neural networks with voltage-sensitive dyes seldom employ conventional intracellular electrodes. This may in part be due to the traditional reliance on compound microscopes for such work. While such microscopes have high light-gathering power, they do not provide depth of field, making working with sharp electrodes difficult. Here we describe a hybrid microscope design, with switchable compound and stereo objectives, that eases the use of conventional intracellular electrodes in optical recording experiments. We use it, in combination with a voltage-sensitive dye and photodiode array, to identify neurons participating in the swim motor program of the marine mollusk Tritonia. This microscope design should be applicable to optical recording studies in many preparations. PMID:17306887

Spray pyrolytic deposition of α-MoO3 film and its use in dye-sensitized solar cell

NASA Astrophysics Data System (ADS)

Tamboli, Parvin S.; Jagtap, Chaitali V.; Kadam, Vishal S.; Ingle, Ravi V.; Vhatkar, Rajiv S.; Mahajan, Smita S.; Pathan, Habib M.

2018-04-01

Thermal decomposition of ammonium para molybdate tetrahydrate precursor has been studied to determine degradation temperatures in air atmosphere. Current work explores the synthesis of α-MoO3 films by an economical spray pyrolysis technique using ammonium para molybdate tetrahydrate precursor in the presence of compressed air. A variety of characterization techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-visible spectroscopy, Fourier transform infrared, and Raman spectroscopy were carried out, and the studies have confirmed that orthorhombic phase formation of MoO3 takes place with spongy mesh-type structure. The study of electro-catalytic activity of α-MoO3 in titania-based dye-sensitized solar cell is also carried out by cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel curves to evaluate its performance as a counter electrode.

Morphological study of electrophoretically deposited TiO2 film for DSSC application

NASA Astrophysics Data System (ADS)

Patel, Alkesh B.; Patel, K. D.; Soni, S. S.; Sonigara, K. K.

2018-05-01

In the immerging field of eco-friendly and low cost photovoltaic devices, dye sensitized solar cell (DSSC) [1] has been investigated as promising alternative to the conventional silicon-based solar cells. In the DSSC device, photoanode is crucial component that take charge of holding sensitizer on it and inject the electrons from the sensitizer to current collector. Nanoporous TiO2 is the most relevant candidate for the preparation of photoanode in DSSCs. Surface properties, morphology, porosity and thickness of TiO2 film as well as preparation technique determine the performance of device. In the present work we have report the study of an effect of nanoporous anatase titanium dioxide (TiO2) film thickness on DSSC performance. Photoanode TiO2 (P25) film was deposited on conducting substrate by electrophoresis technique (EPD) and film thickness was controlled during deposition by applying different current density for a constant time interval. Thickness and surface morphology of prepared films was studied by SEM and transmittance analysis. The same set of photoanode was utilized in DSSC devices using metal free organic dye sensitizer to evaluate the photovoltaic performance. Devices were characterized through Current-Voltage (I-V) characteristic, electrochemical impedance spectroscopy (EIS) and open circuit voltage decay curves. Dependency of device performance corresponding to TiO2 film thickness is investigated through the lifetime kinetics of electron charge transfer mechanism trough impedance fitting. It is concluded that appropriate thickness along with uniformity and porosity are required to align the dye molecules to respond efficiently the incident light photons.

Statistical identification of stimulus-activated network nodes in multi-neuron voltage-sensitive dye optical recordings.

PubMed

Fathiazar, Elham; Anemuller, Jorn; Kretzberg, Jutta

2016-08-01

Voltage-Sensitive Dye (VSD) imaging is an optical imaging method that allows measuring the graded voltage changes of multiple neurons simultaneously. In neuroscience, this method is used to reveal networks of neurons involved in certain tasks. However, the recorded relative dye fluorescence changes are usually low and signals are superimposed by noise and artifacts. Therefore, establishing a reliable method to identify which cells are activated by specific stimulus conditions is the first step to identify functional networks. In this paper, we present a statistical method to identify stimulus-activated network nodes as cells, whose activities during sensory network stimulation differ significantly from the un-stimulated control condition. This method is demonstrated based on voltage-sensitive dye recordings from up to 100 neurons in a ganglion of the medicinal leech responding to tactile skin stimulation. Without relying on any prior physiological knowledge, the network nodes identified by our statistical analysis were found to match well with published cell types involved in tactile stimulus processing and to be consistent across stimulus conditions and preparations.

The application of electrospun titania nanofibers in dye-sensitized solar cells.

PubMed

Krysova, Hana; Zukal, Arnost; Trckova-Barakova, Jana; Chandiran, Aravind Kumar; Nazeeruddin, Mohammad Khaja; Grätzel, Michael; Kavan, Ladislav

2013-01-01

Titania nanofibers were fabricated using the industrial Nanospider(TM) technology. The preparative protocol was optimized by screening various precursor materials to get pure anatase nanofibers. Composite films were prepared by mixing a commercial paste of nanocrystalline anatase particles with the electrospun nanofibers, which were shortened by milling. The composite films were sensitized by Ru-bipyridine dye (coded C106) and the solar conversion efficiency was tested in a dye-sensitized solar cell filled with iodide-based electrolyte solution (coded Z960). The solar conversion efficiency of a solar cell with the optimized composite electrode (η = 7.53% at AM 1.5 irradiation) outperforms that of a solar cell with pure nanoparticle film (η = 5.44%). Still larger improvement was found for lower light intensities. At 10% sun illumination, the best composite electrode showed η = 7.04%, referenced to that of pure nanoparticle film (η = 4.69%). There are non-monotonic relations between the film's surface area, dye sorption capacity and solar performance of nanofiber-containing composite films, but the beneficial effect of the nanofiber morphology for enhancement of the solar efficiency has been demonstrated.

Proton-Induced Trap States, Injection and Recombination Dynamics in Water-Splitting Dye-Sensitized Photoelectrochemical Cells.

PubMed

McCool, Nicholas S; Swierk, John R; Nemes, Coleen T; Saunders, Timothy P; Schmuttenmaer, Charles A; Mallouk, Thomas E

2016-07-06

Water-splitting dye-sensitized photoelectrochemical cells (WS-DSPECs) utilize a sensitized metal oxide and a water oxidation catalyst in order to generate hydrogen and oxygen from water. Although the Faradaic efficiency of water splitting is close to unity, the recombination of photogenerated electrons with oxidized dye molecules causes the quantum efficiency of these devices to be low. It is therefore important to understand recombination mechanisms in order to develop strategies to minimize them. In this paper, we discuss the role of proton intercalation in the formation of recombination centers. Proton intercalation forms nonmobile surface trap states that persist on time scales that are orders of magnitude longer than the electron lifetime in TiO2. As a result of electron trapping, recombination with surface-bound oxidized dye molecules occurs. We report a method for effectively removing the surface trap states by mildly heating the electrodes under vacuum, which appears to primarily improve the injection kinetics without affecting bulk trapping dynamics, further stressing the importance of proton control in WS-DSPECs.

Clinical utility of the additional use of blue dye for indocyanine green for sentinel node biopsy in breast cancer.

PubMed

Ji, Yinan; Luo, Ningbin; Jiang, Yi; Li, Qiuyun; Wei, Wei; Yang, Huawei; Liu, Jianlun

2017-07-01

Indocyanine green (ICG) is widely used as a tracer in sentinel lymph node biopsy (SLNB) of patients with breast cancer. Whether SLNB performance can be improved by supplementing ICG with methylene blue dye remains controversial. This study compared the performance of SLNB when ICG was used alone or with blue dye. Consecutive patients with T1-3 primary breast cancer at our hospital were recruited into our study and randomized to undergo SLNB with ICG alone (n = 62) or with the combination of ICG and blue dye (n = 65). We compared the two methods in terms of identification rate, number and detection time of sentinel lymph nodes (SLNs) removed. SLN identification rate were similar in the absence (95.2%) or presence of blue dye (98.5%, P = 0.578) but significantly, more average nodes were removed when blue dye was used (3.8 ± 1.5 versus 2.7 ± 1.2, P = 0.000), and the average time for detecting each SLN was significantly shorter (3.91 ± 1.87 versus 5.65 ± 2.95 min; P = 0.000). No patient in the study experienced severe adverse reactions or complications. Recurrence of axillary node was detected in one patient (1.6%) using ICG alone but not in any patients using ICG and blue dye. The efficiency and sensitivity of SLNB can be improved by combining ICG with blue dye. Copyright © 2017 Elsevier Inc. All rights reserved.

Transparent nickel selenide alloy counter electrodes for bifacial dye-sensitized solar cells exceeding 10% efficiency.

PubMed

Duan, Yanyan; Tang, Qunwei; He, Benlin; Li, Ru; Yu, Liangmin

2014-11-07

In the current work, we report a series of bifacial dye-sensitized solar cells (DSSCs) that provide power conversion efficiencies of more than 10% from bifacial irradiation. The device comprises an N719-sensitized TiO2 anode, a transparent nickel selenide (Ni-Se) alloy counter electrode (CE), and liquid electrolyte containing I(-)/I3(-) redox couples. Because of the high optical transparency, electron conduction ability, electrocatalytic activity of Ni-Se CEs, as well as dye illumination, electron excitation and power conversion efficiency have been remarkably enhanced. Results indicate that incident light from a transparent CE has a compensation effect to the light from the anode. The impressive efficiency along with simple preparation of the cost-effective Ni-Se alloy CEs highlights the potential application of bifacial illumination technique in robust DSSCs.

Dye-sensitized solar cells using a chlorophyll a derivative as the sensitizer and carotenoids having different conjugation lengths as redox spacers

NASA Astrophysics Data System (ADS)

Wang, Xiao-Feng; Xiang, Junfeng; Wang, Peng; Koyama, Yasushi; Yanagida, Shozo; Wada, Yuji; Hamada, Kazunori; Sasaki, Shin-ichi; Tamiaki, Hitoshi

2005-06-01

Titania-based Grätzel-type solar cells were fabricated by the use of a chlorophyll a derivative (methyl 3-carboxy-3-devinyl-pyropheophorobide a) as the dye sensitizer. A 10% each of carotenoids, including neurosporene, spheroidene, lycopene, anhydrorhodovibrin and spirilloxanthin with numbers of conjugated double bonds, n = 9-13, was added as a conjugated spacer in order to neutralize the dye radical cation and to block the reverse electron transfer. The short-circuit current density ( Jsc) and the solar energy-to-electricity conversion efficiency ( η) systematically increased, with increasing n, from the values of 10.1 mA cm -2 and 3.1% (with no carotenoid) up to 11.5 mA cm -2 and 4.0% (with spirilloxanthin, n = 13), i.e., an enhancement of ≈30%.

Hair dyes are mutagenic: identification of a variety of mutagenic ingredients.

PubMed Central

Ames, B N; Kammen, H O; Yamasaki, E

1975-01-01

We have previously described a sensitive bacterial test for dectecting carcinogens as mutagens. We have previously described a sensitive bacterial test for detecting carcinogens as mutagens. We show here that 89% (150/169) of commercial oxidative-type (hydrogen peroxide) hair dye formulations are mutagenic in this test. Of the 18 components of these hair dyes, nine show various degrees of mutagenicity:2,4-diaminoanisole, 4-nitro-o-phenylenediamine, 2-nitro-p-phenylenediamine, 2,5-diaminoanisole, 2-amino-5-nitrophenol, m-phenylenediamine, o-phenylenediamine, 2-amino-4-nitrophenol, and 2,5-diaminotoluene. Three hair dye components (p-phenylenediamine, 2,5-diaminotuluene, and 2,5-diaminoanisole) become strongly mutagenic after oxidation by H2O2: the mutagenic product of p-phenylenediamine is identified as the known trimer, Bandrowski's base. 2,4-Diaminotoluene, a hair dye component until recently, is also shown to be mutagenic: this compound has been shown to be a carcinogen in rats and is used in large amounts in the polyurethane foam industry. About 20,000,000 people (mostly women) dye their hair in the U.S. and the hazard could be considerable if these chemicals are actually mutagenic and carcinogenic in humans. Images PMID:1094469

Challenges in designing a Taqman-based multiplex assay for the simultaneous detection of Herpes simplex virus types 1 and 2 and Varicella-zoster virus.

PubMed

Weidmann, Manfred; Armbruster, Katrin; Hufert, Frank T

2008-08-01

To optimise molecular detection of herpesviruses an internally controlled multiplex Taqman-PCR for the detection of Herpes simplex virus 1 (HSV1), Herpes simplex virus 2 (HSV2) and Varicella-zoster virus (VZV) was developed. The selection of the dye combination working on the ABI 7700 cycler for this multiplex PCR revealed crosstalk phenomena between several combinations of reference dyes and reporter dyes. A final dye combination with CY5 as reference dye and FAM/JOE/TXR as reporter dyes was selected. The influence of the concentration of the internal positive control (IPC) concentration on the quantitative results of HSV1, HSV2 and VZV positive patient samples was analysed. The results indicate that high IPC concentrations are detrimental for the sensitivity of the multiplex assay and that the presence of the IPC molecule narrows the dynamic range of the duplex PCRs between any of the virus PCRs and the IPC-PCR. The optimised multiplex assay detecting HSV1, HSV2 and VZV using 10(3) IPC molecules showed a performance and sensitivity comparable to that of the individual assays.

Tungsten doped titanium dioxide nanowires for high efficiency dye-sensitized solar cells.

PubMed

Archana, P S; Gupta, Arunava; Yusoff, Mashitah M; Jose, Rajan

2014-04-28

Metal oxide semiconductors offering simultaneously high specific surface area and high electron mobility are actively sought for fabricating high performance nanoelectronic devices. The present study deals with synthesis of tungsten doped TiO2 (W:TiO2) nanowires (diameter ∼50 nm) by electrospinning and evaluation of their performance in dye-sensitized solar cells (DSCs). Similarity in the ionic radii between W(6+) and Ti(4+) and availability of two free electrons per dopant are the rationale for the present study. Materials were characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray fluorescence measurements, and absorption spectroscopy. Nanowires containing 2 at% W:TiO2 gave 90% higher short circuit current density (JSC) (∼15.39 mA cm(-2)) in DSCs with a nominal increase in the open circuit voltage compared with that of the undoped analogue (JSC ∼8.1 mA cm(-2)). The results are validated by multiple techniques employing absorption spectroscopy, electrochemical impedance spectroscopy and open circuit voltage decay. The above studies show that the observed increments resulted from increased dye-loading, electron density, and electron lifetime in tungsten doped samples.

Efficiency enhancement of black dye-sensitized solar cells by newly synthesized D-π-A coadsorbents: a theoretical study.

PubMed

Azar, Yavar T; Payami, Mahmoud

2014-05-28

In this work, using the DFT and TDDFT, we have theoretically studied the electronic and optical properties of the two recently synthesized coadsorbents Y1 and Y2, which were aimed to enhance the efficiency of the black dye-sensitized solar cells. To determine the solvatochromic shifts, both the implicit and mixed implicit-explicit models have been used. The connection between the solvatochromic shifts and the changes in dipole moments in the excitation process is discussed. The difference in excitation charge transfer is utilized to explain the experimentally observed difference in Jsc for Y1 and Y2. Investigating the interactions of I2 molecules in the electrolyte solution with the coadsorbents showed that with Y1 the recombination loss was weakened through decreasing the I2 concentration near the TiO2 surface, whereas with Y2 it was increased. As a result, the higher values of both Jsc and Voc with the Y1 coadsorbent explain its experimentally observed higher efficiency. The present study sheds light on how to design and engineer newer coadsorbents or organic dyes for higher efficiencies.

Ultrafast charge separation dynamics in opaque, operational dye-sensitized solar cells revealed by femtosecond diffuse reflectance spectroscopy

PubMed Central

Ghadiri, Elham; Zakeeruddin, Shaik M.; Hagfeldt, Anders; Grätzel, Michael; Moser, Jacques-E.

2016-01-01

Efficient dye-sensitized solar cells are based on highly diffusive mesoscopic layers that render these devices opaque and unsuitable for ultrafast transient absorption spectroscopy measurements in transmission mode. We developed a novel sub-200 femtosecond time-resolved diffuse reflectance spectroscopy scheme combined with potentiostatic control to study various solar cells in fully operational condition. We studied performance optimized devices based on liquid redox electrolytes and opaque TiO2 films, as well as other morphologies, such as TiO2 fibers and nanotubes. Charge injection from the Z907 dye in all TiO2 morphologies was observed to take place in the sub-200 fs time scale. The kinetics of electron-hole back recombination has features in the picosecond to nanosecond time scale. This observation is significantly different from what was reported in the literature where the electron-hole back recombination for transparent films of small particles is generally accepted to occur on a longer time scale of microseconds. The kinetics of the ultrafast electron injection remained unchanged for voltages between +500 mV and –690 mV, where the injection yield eventually drops steeply. The primary charge separation in Y123 organic dye based devices was clearly slower occurring in two picoseconds and no kinetic component on the shorter femtosecond time scale was recorded. PMID:27095505

Immunoassays for pesticide monitoring

NASA Astrophysics Data System (ADS)

Wengatz, Ingrid; Szurdoki, Ferenc; Swamy, Anand R.; Evans, Lawrence, III; Patonay, Gabor; Stimmann, Eric; Delwiche, Michael; Stoutamire, Donald; Gee, Shirley J.; Hammock, Bruce D.

1995-05-01

This study compares two formats of rapid assays for the detection of pesticides (bromacil and pyrethroid based metabolites): enzyme linked immunosorbent assay (ELISA) and immunoassay with near-infrared (NIR) fluorescence detection. NIR dye immunoassay (NIRDIA) measurements were carried out by using two different instruments, both having a silicon photodiode as the detector and a laser diode for excitation. ELISA and NIRDIA were performed in a tracer format, where the specific antibody is bound to the surface of a microtiter plate well and the tracer with enzyme or fluorescent dye label competes with the analyte for the antibody binding site. It was demonstrated that the NIRDIA is at least as sensitive as the ELISA. Both assays detect pesticides in the (mu) g/L (ppb) range. Hapten- macromolecule-NIR dye-conjugates have been synthesized with various biopolymers (e.g., proteins) as carriers. The use of carrier macromolecules enables convenient purification of the cyanine dye derivatives. The mild conjugation method of the dye is based on isothiocyanate chemistry.

Two-Photon Optical Properties of Near-Infrared Dyes at 1.55 microns Excitation

PubMed Central

Berezin, Mikhail; Zhan, Chun; Lee, Hyeran; Joo, Chulmin; Akers, Walter; Yazdanfar, Siavash; Achilefu, Samuel

2011-01-01

Two-photon (2P) optical properties of cyanine dyes were evaluated using a 2P fluorescence spectrophotometer with 1.55 μm excitation. We report the 2P characteristics of common NIR polymethine dyes, including their 2P action cross-sections and the 2P excited fluorescence lifetime. One of the dyes, DTTC showed the highest 2P action cross-section (~103 ± 19 GM) and relatively high 2P excited fluorescence lifetime and can be used as a scaffold for the synthesis of 2P molecular imaging probes. The 2P action cross-section of DTTC and the lifetime were also highly sensitive to the solvent polarity, providing other additional parameters for its use in optical imaging and the mechanism for probing environmental factors Overall, this study demonstrated the quantitative measurement of 2P properties of NIR dyes and established the foundation for designing molecular probes for 2P imaging applications in the NIR region. PMID:21866928

Adsorption Properties of p -Methyl Red Monomeric-to-Pentameric Dye Aggregates on Anatase (101) Titania Surfaces: First-Principles Calculations of Dye/TiO 2 Photoanode Interfaces for Dye-Sensitized Solar Cells

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

Zhang, Lei; Cole, Jacqueline M.

2014-08-29

The optical and electronic properties of dye aggregates of p-methyl red on a TiO2 anatase (101) surface were modeled as a function of aggregation order (monomer to pentameric dye) via first principles calculations. A progressive red-shifting and intensity increase toward the visible region in UV/vis absorption spectra is observed from monomeric-to-tetrameric dyes, with each molecule in a given aggregate binding to one of the four possible TiO2 (101) adsorption sites. The pentamer exhibits a blue-shifted peak wave- length in the UV/vis absorption spectra and less absorption intensity in the visible region in comparison; a corresponding manifestation of H-aggregation occurs sincemore » one of these five molecules cannot occupy an adsorption site. This finding is consistent with experiment. Calculated density of states (DOS) and partial DOS spectra reveal similar dye…TiO2 nanocomposite conduction band characteristics but different valence band features. Associated molecular orbital distributions reveal dye-to-TiO2 interfacial charge transfer in all five differing aggregate orders; meanwhile, the level of intramolecular charge transfer in the dye becomes progressively localized around its azo- and electron-donating groups, up to the tetrameric dye/TiO2 species. Dye adsorption energies and dye coverage levels are calculated and compared with experiment. Overall, the findings of this case study serve to aid the molecular design of azo dyes towards better performing DSSC devices wherein they are incorporated. In addition, they provide a helpful example reference for understanding the effects of dye aggregation on the adsorbate…TiO2 interfacial optical and electronic properties.« less

pH-sensitive optrode

DOEpatents

Hirschfeld, T.B.; Wang, F.T.

1989-02-07

An apparatus is provided for remotely monitoring pH. A support material is provided on which organic dye molecules are covalently attached at a surface density falling within a predetermined range. The pH dependent fluorescence response of the bound organic dye molecules depends critically on surface density of the organic dye molecules bound to the support material and the nature of the covalent linkage between the organic dye molecules and the support material. The invention is operated by contacting the support material on which the organic dye is attached with the fluid whose pH is to be determined. When in contact, the organic dye on the support material is illuminated so that it is caused to fluoresce. The intensity of organic dye fluorescence is then related to pH. 4 figs.

Ultrasound assisted enhancement in natural dye extraction from beetroot for industrial applications and natural dyeing of leather.

PubMed

Sivakumar, Venkatasubramanian; Anna, J Lakshmi; Vijayeeswarri, J; Swaminathan, G

2009-08-01

There is a growing demand for eco-friendly/non-toxic colorants, specifically for health sensitive applications such as coloration of food and dyeing of child textile/leather garments. Recently, dyes derived from natural sources for these applications have emerged as an important alternative to potentially harmful synthetic dyes and pose need for suitable effective extraction methodologies. The present paper focus on the influence of process parameters for ultrasound assisted leaching of coloring matter from plant materials. In the present work, extraction of natural dye from beetroot using ultrasound has been studied and compared with static/magnetic stirring as a control process at 45 degrees C. The influence of process parameters on the extraction efficiency such as ultrasonic output power, time, pulse mode, effect of solvent system and amount of beetroot has been studied. The use of ultrasound is found to have significant improvement in the extraction efficiency of colorant obtained from beetroot. Based on the experiments it has been found that a mixture of 1:1 ethanol-water with 80W ultrasonic power for 3h contact time provided better yield and extraction efficiency. Pulse mode operation may be useful in reducing electrical energy consumption in the extraction process. The effect of the amount of beetroot used in relation to extraction efficiency has also been studied. Two-stage extraction has been studied and found to be beneficial for improving the yield for higher amounts of beetroot. Significant 8% enhancement in % yield of colorant has been achieved with ultrasound, 80W as compared to MS process both using 1:1 ethanol-water. The coloring ability of extracted beet dye has been tested on substrates such as leather and paper and found to be suitable for dyeing. Ultrasound is also found to be beneficial in natural dyeing of leather with improved rate of exhaustion. Both the dyed substrates have better color values for ultrasonic beet extract as inferred from reflectance measurement. Therefore, the present study clearly offers efficient extraction methodology from natural dye resources such as beetroot with ultrasound even dispensing with external heating. Thereby, also making eco-friendly non-toxic dyeing of fibrous substances a potential viable option.

Flexible Dye-Sensitized Solar Cell Based on Vertical ZnO Nanowire Arrays

PubMed Central

2011-01-01

Flexible dye-sensitized solar cells are fabricated using vertically aligned ZnO nanowire arrays that are transferred onto ITO-coated poly(ethylene terephthalate) substrates using a simple peel-off process. The solar cells demonstrate an energy conversion efficiency of 0.44% with good bending tolerance. This technique paves a new route for building large-scale cost-effective flexible photovoltaic and optoelectronic devices. PMID:27502660

A review of NIR dyes in cancer targeting and imaging.

PubMed

Luo, Shenglin; Zhang, Erlong; Su, Yongping; Cheng, Tianmin; Shi, Chunmeng

2011-10-01

The development of multifunctional agents for simultaneous tumor targeting and near infrared (NIR) fluorescence imaging is expected to have significant impact on future personalized oncology owing to the very low tissue autofluorescence and high tissue penetration depth in the NIR spectrum window. Cancer NIR molecular imaging relies greatly on the development of stable, highly specific and sensitive molecular probes. Organic dyes have shown promising clinical implications as non-targeting agents for optical imaging in which indocyanine green has long been implemented in clinical use. Recently, significant progress has been made on the development of unique NIR dyes with tumor targeting properties. Current ongoing design strategies have overcome some of the limitations of conventional NIR organic dyes, such as poor hydrophilicity and photostability, low quantum yield, insufficient stability in biological system, low detection sensitivity, etc. This potential is further realized with the use of these NIR dyes or NIR dye-encapsulated nanoparticles by conjugation with tumor specific ligands (such as small molecules, peptides, proteins and antibodies) for tumor targeted imaging. Very recently, natively multifunctional NIR dyes that can preferentially accumulate in tumor cells without the need of chemical conjugation to tumor targeting ligands have been developed and these dyes have shown unique optical and pharmaceutical properties for biomedical imaging with superior signal-to-background contrast index. The main focus of this article is to provide a concise overview of newly developed NIR dyes and their potential applications in cancer targeting and imaging. The development of future multifunctional agents by combining targeting, imaging and even therapeutic routes will also be discussed. We believe these newly developed multifunctional NIR dyes will broaden current concept of tumor targeted imaging and hold promise to make an important contribution to the diagnosis and therapeutics for the treatment of cancer. Copyright © 2011 Elsevier Ltd. All rights reserved.

A strategy to minimize the energy offset in carrier injection from excited dyes to inorganic semiconductors for efficient dye-sensitized solar energy conversion.

PubMed

Fujisawa, Jun-Ichi; Osawa, Ayumi; Hanaya, Minoru

2016-08-10

Photoinduced carrier injection from dyes to inorganic semiconductors is a crucial process in various dye-sensitized solar energy conversions such as photovoltaics and photocatalysis. It has been reported that an energy offset larger than 0.2-0.3 eV (threshold value) is required for efficient electron injection from excited dyes to metal-oxide semiconductors such as titanium dioxide (TiO2). Because the energy offset directly causes loss in the potential of injected electrons, it is a crucial issue to minimize the energy offset for efficient solar energy conversions. However, a fundamental understanding of the energy offset, especially the threshold value, has not been obtained yet. In this paper, we report the origin of the threshold value of the energy offset, solving the long-standing questions of why such a large energy offset is necessary for the electron injection and which factors govern the threshold value, and suggest a strategy to minimize the threshold value. The threshold value is determined by the sum of two reorganization energies in one-electron reduction of semiconductors and typically-used donor-acceptor (D-A) dyes. In fact, the estimated values (0.21-0.31 eV) for several D-A dyes are in good agreement with the threshold value, supporting our conclusion. In addition, our results reveal that the threshold value is possible to be reduced by enlarging the π-conjugated system of the acceptor moiety in dyes and enhancing its structural rigidity. Furthermore, we extend the analysis to hole injection from excited dyes to semiconductors. In this case, the threshold value is given by the sum of two reorganization energies in one-electron oxidation of semiconductors and D-A dyes.

Dye-sensitized solar cells using laser processing techniques

NASA Astrophysics Data System (ADS)

Kim, Heungsoo; Pique, Alberto; Kushto, Gary P.; Auyeung, Raymond C. Y.; Lee, S. H.; Arnold, Craig B.; Kafafi, Zakia H.

2004-07-01

Laser processing techniques, such as laser direct-write (LDW) and laser sintering, have been used to deposit mesoporous nanocrystalline TiO2 (nc-TiO2) films for use in dye-sensitized solar cells. LDW enables the fabrication of conformal structures containing metals, ceramics, polymers and composites on rigid and flexible substrates without the use of masks or additional patterning techniques. The transferred material maintains a porous, high surface area structure that is ideally suited for dye-sensitized solar cells. In this experiment, a pulsed UV laser (355nm) is used to forward transfer a paste of commercial TiO2 nanopowder (P25) onto transparent conducting electrodes on flexible polyethyleneterephthalate (PET) and rigid glass substrates. For the cells based on flexible PET substrates, the transferred TiO2 layers were sintered using an in-situ laser to improve electron paths without damaging PET substrates. In this paper, we demonstrate the use of laser processing techniques to produce nc-TiO2 films (~10 μm thickness) on glass for use in dye-sensitized solar cells (Voc = 690 mV, Jsc = 8.7 mA/cm2, ff = 0.67, η = 4.0 % at 100 mW/cm2). This work was supported by the Office of Naval Research.

Method to protect charge recombination in the back-contact dye-sensitized solar cell.

PubMed

Yoo, Beomjin; Kim, Kang-Jin; Lee, Doh-Kwon; Kim, Kyungkon; Ko, Min Jae; Kim, Yong Hyun; Kim, Won Mok; Park, Nam-Gyu

2010-09-13

We prepared a back-contact dye-sensitized solar cell and investigated effect of the sputter deposited thin TiO₂ film on the back-contact ITO electrode on photovoltaic property. The nanocrystalline TiO₂ layer with thickness of about 11 μm formed on a plain glass substrate in the back-contact structure showed higher optical transmittance than that formed on an ITO-coated glass substrate, which led to an improved photocurrent density by about 6.3%. However, photovoltage was found to decrease from 817 mV to 773 mV. The photovoltage recovered after deposition of a 35 nm-thick thin TiO₂ film on the surface of the back-contact ITO electrode. Little difference in time constant for electron transport was found for the back-contact ITO electrodes with and without the sputter deposited thin TiO₂ film. Whereas, time constant for charge recombination increased after introduction of the thin TiO₂ film, indicating that such a thin TiO₂ film protected back electron transfer, associated with the recovery of photovoltage. As the result of the improved photocurrent density without deterioration of photovoltage, the back-contact dye-sensitized solar cell exhibited 13.6% higher efficiency than the ITO-coated glass substrate-based dye-sensitized solar cell.

Method Of Signal Amplification In Multi-Chromophore Luminescence Sensors

DOEpatents

Levitsky, Igor A.; Krivoshlykov, Sergei G.

2004-02-03

A fluorescence-based method for highly sensitive and selective detection of analyte molecules is proposed. The method employs the energy transfer between two or more fluorescent chromophores in a carefully selected polymer matrix. In one preferred embodiment, signal amplification has been achieved in the fluorescent sensing of dimethyl methylphosphonate (DMMP) using two dyes, 3-aminofluoranthene (AM) and Nile Red (NR), in a hydrogen bond acidic polymer matrix. The selected polymer matrix quenches the fluorescence of both dyes and shifts dye emission and absorption spectra relative to more inert matrices. Upon DMMP sorption, the AM fluorescence shifts to the red at the same time the NR absorption shifts to the blue, resulting in better band overlap and increased energy transfer between chromophores. In another preferred embodiment, the sensitive material is incorporated into an optical fiber system enabling efficient excitation of the dye and collecting the fluorescent signal form the sensitive material on the remote end of the system. The proposed method can be applied to multichromophore luminescence sensor systems incorporating N-chromophores leading to N-fold signal amplification and improved selectivity. The method can be used in all applications where highly sensitive detection of basic gases, such as dimethyl methylphosphonate (DMMP), Sarin, Soman and other chemical warfare agents having basic properties, is required, including environmental monitoring, chemical industry and medicine.

Chemical Dosimeter Tube With Coaxial Sensing Rod

NASA Technical Reports Server (NTRS)

Lueck, Dale E.

1993-01-01

Improved length-of-stain (LOS) chemical dosimeter indicates total dose of chemical vapor in air. Made with rods and tubes of various diameters to obtain various sensitivities and dynamic ranges. Sensitivity larger and dose range smaller when more room for diffusion in gap between tube and rod. Offers greater resistance to changing of color of exposed dye back to color of unexposed condition, greater sensitivity, and higher degree of repeatability. Developed to measure doses of gaseous HCI, dosimeter modified by use of other dyes to indicate doses of other chemical vapors.

Density functional theory study of adsorption geometries and electronic structures of azo-dye-based molecules on anatase TiO2 surface for dye-sensitized solar cell applications.

PubMed

Prajongtat, Pongthep; Suramitr, Songwut; Nokbin, Somkiat; Nakajima, Koichi; Mitsuke, Koichiro; Hannongbua, Supa

2017-09-01

Structural and electronic properties of eight isolated azo dyes (ArNNAr', where Ar and Ar' denote the aryl groups containing benzene and naphthalene skeletons, respectively) were investigated by density functional theory (DFT) based on the B3LYP/6-31G(d,p) and TD-B3LYP/6-311G(d,p) methods The effect of methanol solvent on the structural and electronic properties of the azo dyes was elucidated by employing a polarizable continuum model (PCM). Then, the azo dyes adsorbed onto the anatase TiO 2 (101) slab surface through a carboxyl group. The geometries and electronic structures of the adsorption complexes were determined using periodic DFT based on the PWC/DNP method. The calculated adsorption energies indicate that the adsorbed dyes preferentially take configuration of the bidentate bridging rather than chelating or monodentate ester-type geometries. Furthermore, the azo compounds having two carboxyl groups are coordinated to the TiO 2 surface more preferentially through the carboxyl group connecting to the benzene skeleton than through that connecting to the naphthalene skeleton. The dihedral angles (Φ B-N ) between the benzene- and naphthalene-skeleton moieties are smaller than 10° for the adsorbed azo compounds containing one carboxyl group. In contrast, Φ B-N > 30° are obtained for the adsorbed azo compounds containing two carboxyl groups. The almost planar conformations of the former appear to strengthen both π-electrons conjugation and electronic coupling between low-lying unoccupied molecular orbitals of the azo dyes and the conduction band of TiO 2 . On the other hand, such coupling is very weak for the latter, leading to a shift of the Fermi level of TiO 2 in the lower-energy direction. The obtained results are useful to the design and synthesize novel azo-dye-based molecules that give rise to higher photovoltaic performances of the dye-sensitized solar cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Solid polymeric electrolyte based dye-sensitized solar cell with improved stability

NASA Astrophysics Data System (ADS)

Prasad, Narottam; Kumar, Manish; Patel, K. R.; Roy, M. S.

2018-05-01

The impact of polymeric electrolyte was investigated over the performance of dye-sensitized solar cell made with Rose Bengal as sensitizer. Further, the selective influence of TiCl4 treatment and pre-sensitizer deoxycholic acid on nc-TiO2 photoanode was determined in terms of improvement in conversion efficiency of the cell. It is found that the effect of TiCl4 treatment was comparatively more than pre-sensitization with de-oxy cholic acid towards improving the efficiency of the cell. The conversion efficiency on TiCl4 treatment was 0.2% whereas on pre-sensitization with deoxy chollic acid it was 0.1%. The combined effect of both TiCl4 treatment & pre-sensitization with deoxycholic acid leads conversion efficiency to 0.33%.

Calcium Sensitive Fluorescent Dyes Fluo-4 and Fura Red under Pressure: Behaviour of Fluorescence and Buffer Properties under Hydrostatic Pressures up to 200 MPa

PubMed Central

Vass, H.; Reischl, B.; Allen, R. J.; Friedrich, O.

2016-01-01

The fluorescent Ca2+ sensitive dyes Fura Red (ratiometric) and Fluo-4 (non-ratiometric) are widely utilized for the optical assessment of Ca2+ fluctuations in vitro as well as in situ. The fluorescent behavior of these dyes is strongly depends on temperature, pH, ionic strength and pressure. It is crucial to understand the response of these dyes to pressure when applying calcium imaging technologies in the field of high pressure bioscience. Therefore, we use an optically accessible pressure vessel to pressurize physiological Ca2+-buffered solutions at different fixed concentrations of free Ca2+ (1 nM to 25.6 μM) and a specified dye concentration (12 μM) to pressures of 200 MPa, and record dye fluorescence intensity. Our results show that Fluo-4 fluorescence intensity is reduced by 31% per 100 MPa, the intensity of Fura Red is reduced by 10% per 100 MPa. The mean reaction volume for the dissociation of calcium from the dye molecules Δdv¯ is determined to -17.8 ml mol-1 for Fluo-4 and -21.3 ml mol-1 for Fura Red. Additionally, a model is presented that is used to correct for pressure-dependent changes in pH and binding affinity of Ca2+ to EGTA, as well as to determine the influence of these changes on dye fluorescence. PMID:27764134

Multispectral photoacoustic decomposition with localized regularization for detecting targeted contrast agent

NASA Astrophysics Data System (ADS)

Tavakoli, Behnoosh; Chen, Ying; Guo, Xiaoyu; Kang, Hyun Jae; Pomper, Martin; Boctor, Emad M.

2015-03-01

Targeted contrast agents can improve the sensitivity of imaging systems for cancer detection and monitoring the treatment. In order to accurately detect contrast agent concentration from photoacoustic images, we developed a decomposition algorithm to separate photoacoustic absorption spectrum into components from individual absorbers. In this study, we evaluated novel prostate-specific membrane antigen (PSMA) targeted agents for imaging prostate cancer. Three agents were synthesized through conjugating PSMA-targeting urea with optical dyes ICG, IRDye800CW and ATTO740 respectively. In our preliminary PA study, dyes were injected in a thin wall plastic tube embedded in water tank. The tube was illuminated with pulsed laser light using a tunable Q-switch ND-YAG laser. PA signal along with the B-mode ultrasound images were detected with a diagnostic ultrasound probe in orthogonal mode. PA spectrums of each dye at 0.5 to 20 μM concentrations were estimated using the maximum PA signal extracted from images which are obtained at illumination wavelengths of 700nm-850nm. Subsequently, we developed nonnegative linear least square optimization method along with localized regularization to solve the spectral unmixing. The algorithm was tested by imaging mixture of those dyes. The concentration of each dye was estimated with about 20% error on average from almost all mixtures albeit the small separation between dyes spectrums.

Investigation of electronic band structure and charge transfer mechanism of oxidized three-dimensional graphene as metal-free anodes material for dye sensitized solar cell application

NASA Astrophysics Data System (ADS)

Loeblein, Manuela; Bruno, Annalisa; Loh, G. C.; Bolker, Asaf; Saguy, Cecile; Antila, Liisa; Tsang, Siu Hon; Teo, Edwin Hang Tong

2017-10-01

Dye-sensitized solar cells (DSSCs) offer an optimal trade-off between conversion-efficiency and low-cost fabrication. However, since all its electrodes need to fulfill stringent work-function requirements, its materials have remained unchanged since DSSC's first report early-90s. Here we describe a new material, oxidized-three-dimensional-graphene (o-3D-C), with a band gap of 0.2 eV and suitable electronic band-structure as alternative metal-free material for DSSCs-anodes. o-3D-C/dye-complex has a strong chemical bonding via carboxylic-group chemisorption with full saturation after 12 sec at capacity of ∼450 mg/g (600x faster and 7x higher than optimized metal surfaces). Furthermore, fluorescence quenching of life-time by 28-35% was measured demonstrating charge-transfer from dye to o-3D-C.

Dye-sensitized solar cell employing zinc oxide aggregates grown in the presence of lithium

DOEpatents

Zhang, Qifeng; Cao, Guozhong

2013-10-15

Provided are a novel ZnO dye-sensitized solar cell and method of fabricating the same. In one embodiment, deliberately added lithium ions are used to mediate the growth of ZnO aggregates. The use of lithium provides ZnO aggregates that have advantageous microstructure, morphology, crystallinity, and operational characteristics. Employing lithium during aggregate synthesis results in a polydisperse collection of ZnO aggregates favorable for porosity and light scattering. The resulting nanocrystallites forming the aggregates have improved crystallinity and more favorable facets for dye molecule absorption. The lithium synthesis improves the surface stability of ZnO in acidic dyes. The procedures developed and disclosed herein also help ensure the formation of an aggregate film that has a high homogeneity of thickness, a high packing density, a high specific surface area, and good electrical contact between the film and the fluorine-doped tin oxide electrode and among the aggregate particles.

Dye-sensitized MIL-101 metal organic frameworks loaded with Ni/NiO{sub x} nanoparticles for efficient visible-light-driven hydrogen generation

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

Liu, Xin-Ling; Wang, Rong; Yuan, Yu-Peng, E-mail: yupengyuan@ahu.edu.cn, E-mail: cxue@ntu.edu.sg

2015-10-01

The Ni/NiO{sub x} particles were in situ photodeposited on MIL-101 metal organic frameworks as catalysts for boosting H{sub 2} generation from Erythrosin B dye sensitization under visible-light irradiation. The highest H{sub 2} production rate of 125 μmol h{sup −1} was achieved from the system containing 5 wt. % Ni-loaded MIL-101 (20 mg) and 30 mg Erythrosin B dye. Moreover, the Ni/NiO{sub x} catalysts show excellent stability for long-term photocatalytic reaction. The enhancement on H{sub 2} generation is attributed to the efficient charge transfer from photoexcited dye to the Ni catalyst via MIL-101. Our results demonstrate that the economical Ni/NiO{sub x}more » particles are durable and active catalysts for photocatalytic H{sub 2} generation.« less

[Reactions to fragrances and textiles].

PubMed

Hausen, B M

1987-12-01

Allergic reactions to fragrances are caused by perfumes and perfume-containing items of our environment. The most important allergen is cinnamic aldehyde. By means of the mixed perfume test recommended by the International Contact Dermatitis Research Group (ICDRG), however, we are not able to detect more than half of the patients suffering from perfume allergy. Thus we suggest to make use of two new test series comprising most of the relevant fragrance components. Allergic reactions to textiles are mostly due to textile dyes. Special regard must be given to the disperse dyes of the azo group in nylon stockings and tights. The three most important allergens are disperse yellow 3, disperse orange 3, and disperse red 1. According to our experiments, the sensitizing potency of these dyes is comparatively low. In contrast, two recently introduced azo dyes (disperse blue 106 and 124), which are mainly used in blouses and trousers, proved to be strong sensitizers.

Pi-pi* orbital transitions and photo-degeneracy of C.acuminata sensitized solar cells

NASA Astrophysics Data System (ADS)

Abodunrin, T.; Boyo, A.; Usikalu, M.; Obafemi, L.; Oladapo, O.; Kotsedi, L.; Yenus, Z.; Maaza, M.

2017-04-01

Dye-sensitized solar cells (DSSCs) have acquired great prominence as favourable low-cost photovoltaics due to their ease of fabrication, all- year -availability, ease of obtaining raw materials and adjustable optical properties like transparency and colour. These advantages coupled with the ability to work under poor lighting makes them a suitable candidate for next generation of research. In this research, C.acuminata-sensitized photo anodes play an important role for achieving high performance since the porous metal oxide films provide a large specific surface area for dye loading and the possibility to extend the absorption threshold of past studies of sensitizers. The doctor blade method and high-temperature sintering were some of the methods used in the fabrication of the photo anode. A study of the performance of the C.acuminata-DSSCs with four different electrolyte sensitizers based on iodide redox mediator is determined. The result is DSSCs that exhibit a maximum power output of 39.37 W, fill factor of 0.7 and a power conversion efficiency of 0.6% under unfavourable sunlight intensity conditions and photo-degradation of about 37.5 % in absorbance after 425 suns.

Enhanced absorption in a reverse saturable absorbing dye blended with carbon nanotubes.

PubMed

Webster, Scott; Reyes-Reyes, Marisol; Williams, Richard; Carroll, David L

2008-12-01

Using nonlinear absorption at 532 nm in the nanosecond temporal regime, we have measured the low fluence nonlinear transmittance properties of the reverse saturable absorbing carbocyanine dye, 1,1',3,3,3',3'-hexamethylindotricarbocyanine iodide (HITCI), blended with well dispersed carbon nanotubes. The nonlinear optical properties of the blends are strongly dependent on the ratio of dye to nanotubes in solution. In the case where the nanotubes per dye molecule ratio is large, we see a distinctive enhancement in optical fluence limiting properties of the system, suggesting enhanced absorption of the excited states. However, when the nanotube to dye ratio decreases, the system's response is dominated by the behavior of the dye. We suggest that this can be understood as a two component system in which sensitized dye molecules associated with the nanotubes have an effectively different optical cross-section from the dye molecules far from the nanotubes. From classical antennae considerations, this is expected.

Photodetectors based on single-walled carbon nanotubes and thiamonomethinecyanine J-aggregates on flexible substrates

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

Fedorov, I. V., E-mail: i-v-fedorov@mail.ru; Emel’yanov, A. V.; Romashkin, A. V.

2015-09-15

The present paper is devoted to observations of the photoresistive effect in multilayer structures with a sensitive layer of J-aggregates of thiamonomethinecyanine polymethine dye and a transparent electrode of a conductive carbon-nanotube network on a flexible polyethylenenaphtalate substrate. The effect of narrow-band emission with a wavelength of 465 nm on a change in the conductivity of the fabricated structures is studied. The prepared samples are studied by atomic-force microscopy, Raman spectroscopy, and spectrophotometry methods. It is shown that these structures are photosensitive to the indicated spectral region, and the dye layer is a film of dye J-aggregates. The change inmore » the sample conductivity upon exposure to light one hundred times exceeds the dark conductivity. In general, the principal possibility of developing a photoresistive detector based on J-aggregates of cyanine dyes on flexible supports on account of the use of transparent and conductive carbon-nanotube layers is shown.« less

Rapid and sensitive detection of human astrovirus in water samples by loop-mediated isothermal amplification with hydroxynaphthol blue dye.

PubMed

Yang, Bo-Yun; Liu, Xiao-Lu; Wei, Yu-Mei; Wang, Jing-Qi; He, Xiao-Qing; Jin, Yi; Wang, Zi-Jian

2014-02-14

The aim of this paper was to develop a reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for rapid, sensitive and inexpensive detection of astrovirus. The detection limit of LAMP using in vitro RNA transcripts was 3.6 × 10 copies·μL⁻¹, which is as sensitive as the presently used PCR assays. However, the LAMP products could be identified as different colors with the naked eye following staining with hydroxynaphthol blue dye (HNB). No cross-reactivity with other gastroenteric viruses (rotavirus and norovirus) was observed, indicating the relatively high specificity of LAMP. The RT-LAMP method with HNB was used to effectively detect astrovirus in reclaimed water samples. The LAMP technique described in this study is a cheap, sensitive, specific and rapid method for the detection of astrovirus. The RT-LAMP method can be simply applied for the specific detection of astrovirus and has the potential to be utilized in the field as a screening test.

Mixed metal oxides for dye-sensitized solar cell using zinc titanium layered double hydroxide as precursor

NASA Astrophysics Data System (ADS)

Liu, Jianqiang; Qin, Yaowei; Zhang, Liangji; Xiao, Hongdi; Song, Jianye; Liu, Dehe; Leng, Mingzhe; Hou, Wanguo; Du, Na

2013-12-01

Mixed metal oxides (MMO) are always obtained from layered double hydroxide (LDH) by thermal decomposition. In the present work, a zinc titanium LDH with the zinc titanium molar ratio of 4.25 was prepared by urea method and ZnO-based mixed oxides were obtained by calcining at or over 500°C. The MMO was used as electrodes for dye sensitized solar cell (DSSC). The cells constructed by films of prepared composite materials using a N719 as dye were prepared. The efficiency values of these cells are 0.691%, 0.572% and 0.302% with MMO prepared at 500, 600 and 700°C, respectively.

Extrinsic Fluorescent Dyes as Tools for Protein Characterization

PubMed Central

Hawe, Andrea; Sutter, Marc

2008-01-01

Noncovalent, extrinsic fluorescent dyes are applied in various fields of protein analysis, e.g. to characterize folding intermediates, measure surface hydrophobicity, and detect aggregation or fibrillation. The main underlying mechanisms, which explain the fluorescence properties of many extrinsic dyes, are solvent relaxation processes and (twisted) intramolecular charge transfer reactions, which are affected by the environment and by interactions of the dyes with proteins. In recent time, the use of extrinsic fluorescent dyes such as ANS, Bis-ANS, Nile Red, Thioflavin T and others has increased, because of their versatility, sensitivity and suitability for high-throughput screening. The intention of this review is to give an overview of available extrinsic dyes, explain their spectral properties, and show illustrative examples of their various applications in protein characterization. PMID:18172579

Patch testing to a textile dye mix by the international contact dermatitis research group.

PubMed

Isaksson, Marléne; Ale, Iris; Andersen, Klaus E; Diepgen, Thomas; Goh, Chee-Leok; Goossens R, An; Jerajani, Hemangi; Maibach, Howard I; Sasseville, Denis; Bruze, Magnus

2015-01-01

Disperse dyes are well-known contact sensitizers not included in the majority of commercially available baseline series. To investigate the outcome of patch testing to a textile dye mix (TDM) consisting of 8 disperse dyes. Two thousand four hundred ninety-three consecutive dermatitis patients in 9 dermatology clinics were patch tested with a TDM 6.6%, consisting of Disperse (D) Blue 35, D Yellow 3, D Orange 1 and 3, D Red 1 and 17, all 1.0% each, and D Blue 106 and D Blue 124, each 0.3%. 90 reacted positively to the TDM. About 92.2% of the patients allergic to the TDM were also tested with the 8 separate dyes. Contact allergy to TDM was found in 3.6% (1.3-18.2) Simultaneous reactivity to p-phenylenediamine was found in 61.1% of the TDM-positive patients. Contact allergy to TDM and not to other p-amino-substituted sensitizers was diagnosed in 1.2%. The most frequent dye allergen in the TDM-positive patients was D Orange 3. Over 30% of the TDM allergic patients had been missed if only the international baseline series was tested. Contact allergy to TDM could explain or contribute to dermatitis in over 20% of the patients. Textile dye mix should be considered for inclusion into the international baseline series.

The factors influencing nonlinear characteristics of the short-circuit current in dye-sensitized solar cells investigated by a numerical model.

PubMed

Shi, Yushuai; Dong, Xiandui

2013-06-24

A numerical model for interpretation of the light-intensity-dependent nonlinear characteristics of the short-circuit current in dye-sensitized solar cells is suggested. The model is based on the continuity equation and includes the influences of the nongeminate recombination between electrons and electron acceptors in the electrolyte and the geminate recombination between electrons and oxidized dye molecules. The influences of the order and rate constant of the nongeminate recombination reaction, the light-absorption coefficient of the dye, the film thickness, the rate constant of geminate recombination, and the regeneration rate constant on the nonlinear characteristics of the short-circuit current are simulated and analyzed. It is proposed that superlinear and sublinear characteristics of the short-circuit current should be attributed to low electron-collection efficiency and low dye-regeneration efficiency, respectively. These results allow a deep understanding of the origin of the nonlinear characteristics of the short-circuit current in solar cells. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct observation of sequential oxidations of a titania-bound molecular proxy catalyst generated through illumination of molecular sensitizers

NASA Astrophysics Data System (ADS)

Chen, Hsiang-Yun; Ardo, Shane

2018-01-01

Natural photosynthesis uses the energy in sunlight to oxidize or reduce reaction centres multiple times, therefore preparing each reaction centre for a multiple-electron-transfer reaction that will ultimately generate stable reaction products. This process relies on multiple chromophores per reaction centre to quickly generate the active state of the reaction centre and to outcompete deleterious charge recombination. Using a similar design principle, we report spectroscopic evidence for the generation of a twice-oxidized TiO2-bound molecular proxy catalyst after low-intensity visible-light excitation of co-anchored molecular Ru(II)-polypyridyl dyes. Electron transfer from an excited dye to TiO2 generated a Ru(III) state that subsequently and repeatedly reacted with neighbouring Ru(II) dyes via self-exchange electron transfer to ultimately oxidize a distant co-anchored proxy catalyst before charge recombination. The largest yield for twice-oxidized proxy catalysts occurred when they were present at low coverage, suggesting that large dye/electrocatalyst ratios are also desired in dye-sensitized photoelectrochemical cells.

Synthesis of 8-Aryl-O-methylcyanidins and Their Usage for Dye-Sensitized Solar Cell Devices.

PubMed

Kimura, Yuki; Oyama, Kin-Ichi; Murata, Yasujiro; Wakamiya, Atsushi; Yoshida, Kumi

2017-02-16

Anthocyanins as natural pigments are colorful and environmentally compatible dyes for dye-sensitized solar cells (DSSCs). To increase the efficiency, we designed and synthesized unnatural O -methylflavonols and O -methylcyanidins that possess an aryl group at the 8-position. We synthesized per - O -methylquercetin from quercetin, then using selective demethylation prepared various O -methylquercetins. Using the Suzuki-Miyaura coupling reaction, 8-arylation of per - O -methylquercetin was achieved. Using a LiAlH₄ reduction or Clemmensen reduction, these flavonols were transformed to the corresponding cyanidin derivatives in satisfactory yields. Using these dyes, we fabricated DSSCs, and their efficiency was investigated. The efficiency of tetra - O -methylflavonol was 0.31%. However, the introduction of the 8-aryl residue increased the efficiency to 1.04%. In comparison to these flavonols, O -methylcyanidins exhibited a lower efficiency of 0.05% to 0.52%. The introduction of the 8-aryl group into the cyanidin derivatives did not result in a remarkable increase in the efficiency. These phenomena may be due to the poor fit of the HOMO-LUMO level of the dyes to the TiO₂ conduction band.

Potassium-doped zinc oxide as photocathode material in dye-sensitized solar cells.

PubMed

Bai, Jie; Xu, Xiaobao; Xu, Ling; Cui, Jin; Huang, Dekang; Chen, Wei; Cheng, Yibing; Shen, Yan; Wang, Mingkui

2013-04-01

ZnO nanoparticles are doped with K and applied in p-type dye-sensitized solar cells (DSCs). The microstructure and dynamics of hole transportation and recombination are investigated. The morphology of the K-doped ZnO nanoparticles shows a homogeneous distribution with sizes in the range 30-40 nm. When applied in p-type DSCs in combination with C343 as sensitizer, the K-doped ZnO nanoparticles achieve a photovoltaic power conversion efficiency of 0.012 % at full-intensity sunlight. A further study on the device by transient photovoltage/photocurrent decay measurements shows that the K-doped ZnO nanoparticles have an appreciable hole diffusion coefficient (ca. 10(-6) cm(2) s(-1) ). Compared to the widely used p-type NiO nanoparticles, this advantage is crucial for further improving the efficiency of p-type DSCs. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extremely enhanced photovoltaic properties of dye-sensitized solar cells by sintering mesoporous TiO2 photoanodes with crystalline titania chelated by acetic acid

NASA Astrophysics Data System (ADS)

Liu, Bo-Tau; Chou, Ya-Hui; Liu, Jin-Yan

2016-04-01

The study presents a significant improvement on the performance of dye-sensitized solar cells (DSSCs) through incorporating the crystalline titania chelated by acetic acid (TAc) into the mesoporous TiO2 photoanodes. The effects of TAc on the blocking layer, mesoporous TiO2 layer, and post-treatment have been investigated. The TAc blocking layer displays compact construction, revealing superior response time and resistance to suppress dark current compared to the blocking layer made from titanium(IV) isopropoxide (TTIP). The power conversion efficiency of DSSCs with the TAc treatment can reach as high as 10.49%, which is much higher than that of pristine DSSCs (5.67%) and that of DSSCs treated by TTIP (7.86%). We find that the TAc incorporation can lead to the decrease of charge transfer resistance and the increase of dye adsorption. The result may be attributed to the fact that the TAc possesses high crystallinity, exposed (101) planes, and acid groups chelated on surface, which are favorable for dye attachment and strong bonding at the FTO/TiO2 and the TiO2/TiO2 interfaces, These improvements result in the remarkable increase of photocurrent and thereby that of power conversion efficiency.

Sensitivity and Specificity of Cardiac Tissue Discrimination Using Fiber-Optics Confocal Microscopy.

PubMed

Huang, Chao; Sachse, Frank B; Hitchcock, Robert W; Kaza, Aditya K

2016-01-01

Disturbances of the cardiac conduction system constitute a major risk after surgical repair of complex cases of congenital heart disease. Intraoperative identification of the conduction system may reduce the incidence of these disturbances. We previously developed an approach to identify cardiac tissue types using fiber-optics confocal microscopy and extracellular fluorophores. Here, we applied this approach to investigate sensitivity and specificity of human and automated classification in discriminating images of atrial working myocardium and specialized tissue of the conduction system. Two-dimensional image sequences from atrial working myocardium and nodal tissue of isolated perfused rodent hearts were acquired using a fiber-optics confocal microscope (Leica FCM1000). We compared two methods for local application of extracellular fluorophores: topical via pipette and with a dye carrier. Eight blinded examiners evaluated 162 randomly selected images of atrial working myocardium (n = 81) and nodal tissue (n = 81). In addition, we evaluated the images using automated classification. Blinded examiners achieved a sensitivity and specificity of 99.2 ± 0.3% and 98.0 ± 0.7%, respectively, with the dye carrier method of dye application. Sensitivity and specificity was similar for dye application via a pipette (99.2 ± 0.3% and 94.0 ± 2.4%, respectively). Sensitivity and specificity for automated methods of tissue discrimination were similarly high. Human and automated classification achieved high sensitivity and specificity in discriminating atrial working myocardium and nodal tissue. We suggest that our findings facilitate clinical translation of fiber-optics confocal microscopy as an intraoperative imaging modality to reduce the incidence of conduction disturbances during surgical correction of congenital heart disease.

Near-infrared dyes and upconverting phosphors as biomolecule labels and probes

NASA Astrophysics Data System (ADS)

Patonay, Gabor; Strekowski, Lucjan; Nguyen, Diem-Ngoc; Seok, Kim Jun

2007-02-01

Near-Infrared (NIR) absorbing chromophores have been used in analytical and bioanalytical chemistry extensively, including for determination of properties of biomolecules, DNA sequencing, immunoassays, capillary electrophoresis (CE) separations, etc. The major analytical advantages of these dyes are low background interference and high molar absorptivities. NIR dyes have additional advantages due to their sensitivity to microenvironmental changes. Spectral changes induced by the microenvironment are not desirable if the labels are used as a simple reporting group, e.g., during a biorecognition reaction. For these applications upconverting phosphors seem to be a better choice. There are several difficulties in utilizing upconverting phosphors as reporting labels. These are: large physical size, no reactive groups and insolubility in aqueous systems. This presentation will discuss how these difficulties can be overcome for bioanalytical and forensic applications. During these studies we also have investigated how to reduce physical size of the phosphor by simple grinding without losing activity and how to attach reactive moiety to the phosphor to covalently bind to the biomolecule of interest. It has to be emphasized that the described approach is not suitable for medical applications and the results of this research are not applicable in medical applications. For bioanalytical and forensic applications upconverting phosphors used as reporting labels have several advantages. They are excited with lasers that are red shifted respective to phosphorescence, resulting in no light scatter issues during detection. Also some phosphors are excited using eye safe lasers. In addition energy transfer to NIR dyes is possible, allowing detection schemes using donor-acceptor pairs. Data is presented to illustrate the feasibility of this phenomenon. If microenvironmental sensitivity is required, then specially designed NIR dyes can be used as acceptor labels. Several novel dyes have been synthesized in our laboratories for that purpose.

Platinum-free, carbon-based materials as efficient counter electrodes for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Widiyandari, Hendri; Prasetio, Adi; Purwanto, Agus; Subagio, Agus; Hidayat, Rachmat

2018-06-01

The electrocatalytic potential of carbon materials makes them the most viable candidate to replace Pt as a counter electrode (CE) in dye-sensitized solar cells (DSSCs). In this research, we report our study using graphite, CNT/graphite composite, CNT, and Pt-based CEs in DSSCs. The electrochemical impedance spectroscopy (EIS) measurement showed that the CNT-based CE (CNT-CE) has the lowest charge transport resistance (R ct) compared with graphite and the CNT/graphite composite. The photovoltaic performance measurement showed that the CNT-CE resulted in a short-circuit photocurrent density (J sc) of 3.59 mA·cm‑2 whereas the Pt-based CE (Pt-CE) resulted in a J sc of 2.76 mA·cm‑2.

Electrical properties of graphene film for counter electrode in dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Khalifa, Ali; Shafie, S.; Hasan, W. Z. W.; Lim, H. N.; Rusop, M.; Samaila, Buda

2018-05-01

A graphene counter electrode for dye-sensitized solar cell was prepared simply by drop casting method on a conducting FTO glass at room temperature. Raman spectroscopy was used to study the defection in the graphene films. The sheet resistance was also measured and recoded minimum value of 7.04 Ω/□ at 22.19µm thickness. The casted films show good adhesion to substrates with low defects. A DSSC based on graphene counter electrode demonstrates reasonable conversion efficiency of 2.78% with short circuit current of 7.60mA, open circuit voltage of 0.69V and fill factor of 0.52. The high conductivity and low defects render the prepared graphene dispersion for DSSCs' CE application.

Excessive Labeling Technique Provides a Highly Sensitive Fluorescent Probe for Real-time Monitoring of Biodegradation of Biopolymer Pharmaceuticals in vivo.

PubMed

Terekhov, S S; Smirnov, I V; Shamborant, O G; Zenkova, M A; Chernolovskaya, E L; Gladkikh, D V; Murashev, A N; Dyachenko, I A; Knorre, V D; Belogurov, A A; Ponomarenko, N A; Deyev, S M; Vlasov, V V; Gabibov, A G

2014-10-01

Recombinant proteins represent a large sector of the biopharma market. Determination of the main elimination pathways raises the opportunities to significantly increase their half-lives in vivo. However, evaluation of biodegradation of pharmaceutical biopolymers performed in the course of pre-clinical studies is frequently complicated. Noninvasive pharmacokinetic and biodistribution studies in living organism are possible using proteins conjugated with near-infrared dyes. In the present study we designed a highly efficient probe based on fluorescent dye self-quenching for monitoring of in vivo biodegradation of recombinant human butyrylcholinesterase. The maximum enhancement of integral fluorescence in response to degradation of an intravenously administered enzyme was observed 6 h after injection. Importantly, excessive butyrylcholinesterase labeling with fluorescent dye results in significant changes in the pharmacokinetic properties of the obtained conjugate. This fact must be taken into consideration during future pharmacokinetic studies using in vivo bioimaging.

The layer boundary effect on multi-layer mesoporous TiO 2 film based dye sensitized solar cells

DOE PAGES

Xu, Feng; Zhu, Kai; Zhao, Yixin

2016-10-10

Multi-layer mesoporous TiO 2 prepared by screen printing is widely used for fabrication of high-efficiency dye-sensitized solar cells (DSSCs). Here, we compare the three types of ~10 um thick mesoporous TiO 2 films, which were screen printed as 1-, 2- and 4-layers using the same TiO 2 nanocrystal paste. The layer boundary of the multi-layer mesoporous TiO 2 films was observed in the cross-section SEM. The existence of a layer boundary could reduce the photoelectron diffusion length with the increase of layer number. However, the photoelectron diffusion lengths of the Z907 dye sensitized solar cells based on these different layeredmore » mesoporous TiO 2 films are all longer than the film thickness. Consequently, the photovoltaic performance seems to have little dependence on the layer number of the multi-layer TiO 2 based DSSCs.« less

Dye-sensitized PS-b-P2VP-templated nickel oxide films for photoelectrochemical applications

PubMed Central

Massin, Julien; Bräutigam, Maximilian; Kaeffer, Nicolas; Queyriaux, Nicolas; Field, Martin J.; Schacher, Felix H.; Popp, Jürgen; Chavarot-Kerlidou, Murielle; Dietzek, Benjamin; Artero, Vincent

2015-01-01

Moving from homogeneous water-splitting photocatalytic systems to photoelectrochemical devices requires the preparation and evaluation of novel p-type transparent conductive photoelectrode substrates. We report here on the sensitization of polystyrene-block-poly-(2-vinylpyridine) (PS-b-P2VP) diblock copolymer-templated NiO films with an organic push–pull dye. The potential of these new templated NiO film preparations for photoelectrochemical applications is compared with NiO material templated by F108 triblock copolymers. We conclude that NiO films are promising materials for the construction of dye-sensitized photocathodes to be inserted into photoelectrochemical (PEC) cells. However, a combined effort at the interface between materials science and molecular chemistry, ideally funded within a Global Artificial Photosynthesis Project, is still needed to improve the overall performance of the photoelectrodes and progress towards economically viable PEC devices. PMID:26052420

Dye-sensitized PS-b-P2VP-templated nickel oxide films for photoelectrochemical applications.

PubMed

Massin, Julien; Bräutigam, Maximilian; Kaeffer, Nicolas; Queyriaux, Nicolas; Field, Martin J; Schacher, Felix H; Popp, Jürgen; Chavarot-Kerlidou, Murielle; Dietzek, Benjamin; Artero, Vincent

2015-06-06

Moving from homogeneous water-splitting photocatalytic systems to photoelectrochemical devices requires the preparation and evaluation of novel p-type transparent conductive photoelectrode substrates. We report here on the sensitization of polystyrene-block-poly-(2-vinylpyridine) (PS-b-P2VP) diblock copolymer-templated NiO films with an organic push-pull dye. The potential of these new templated NiO film preparations for photoelectrochemical applications is compared with NiO material templated by F108 triblock copolymers. We conclude that NiO films are promising materials for the construction of dye-sensitized photocathodes to be inserted into photoelectrochemical (PEC) cells. However, a combined effort at the interface between materials science and molecular chemistry, ideally funded within a Global Artificial Photosynthesis Project, is still needed to improve the overall performance of the photoelectrodes and progress towards economically viable PEC devices.

The layer boundary effect on multi-layer mesoporous TiO 2 film based dye sensitized solar cells

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

Xu, Feng; Zhu, Kai; Zhao, Yixin

Multi-layer mesoporous TiO 2 prepared by screen printing is widely used for fabrication of high-efficiency dye-sensitized solar cells (DSSCs). Here, we compare the three types of ~10 um thick mesoporous TiO 2 films, which were screen printed as 1-, 2- and 4-layers using the same TiO 2 nanocrystal paste. The layer boundary of the multi-layer mesoporous TiO 2 films was observed in the cross-section SEM. The existence of a layer boundary could reduce the photoelectron diffusion length with the increase of layer number. However, the photoelectron diffusion lengths of the Z907 dye sensitized solar cells based on these different layeredmore » mesoporous TiO 2 films are all longer than the film thickness. Consequently, the photovoltaic performance seems to have little dependence on the layer number of the multi-layer TiO 2 based DSSCs.« less

Hydrothermal growth of highly monodispersed TiO2 nanoparticles: Functional properties and dye-sensitized solar cell performance

NASA Astrophysics Data System (ADS)

Navaneethan, M.; Nithiananth, S.; Abinaya, R.; Harish, S.; Archana, J.; Sudha, L.; Ponnusamy, S.; Muthamizhchelvan, C.; Ikeda, H.; Hayakawa, Y.

2017-10-01

Monodispersed anatase TiO2 nanoparticles were synthesized by hydrothermal method using citric acid as a capping agent. The effect of citric acid and the growth time on the formation of TiO2, functional properties and dye-sensitized solar cell performances were investigated. X-ray diffraction pattern (XRD) and Raman spectroscopy results revealed that the TiO2 nanoparticles possess the anatase phase. Transmission electron microscopy (TEM) measurement revealed the formation of spherical nanoparticles with monodispersity in size and morphology. An average size of 14 nm was obtained for the growth period of 15 h. The maximum efficiency (η) of dye-sensitized solar cell was achieved for TiO2 nanoparticles grown for 15 h as 7.66% which was higher than that of commercial P25 TiO2 (5.23%) and uncapped nanoparticles (3.68%).

Environment sensitive fluorescent analogue of biologically active oxazoles differentially recognizes human serum albumin and bovine serum albumin: Photophysical and molecular modeling studies.

PubMed

Maiti, Jyotirmay; Biswas, Suman; Chaudhuri, Ankur; Chakraborty, Sandipan; Chakraborty, Sibani; Das, Ranjan

2017-03-15

An environment sensitive fluorophore, 4-(5-(4-(dimethylamino)phenyl)oxazol-2-yl)benzoic acid (DMOBA), that closely mimics biologically active 2,5-disubstituited oxazoles has been designed to probe two homologous serum proteins, human serum albumin (HSA) and bovine serum albumin (BSA) by means of photophysical and molecular modeling studies. This fluorescent analogue exhibits solvent polarity sensitive fluorescence due to an intramolecular charge transfer in the excited state. In comparison to water, the steady state emission spectra of DMOBA in BSA is characterized by a greater blue shift (~10nm) and smaller Stokes' shift (~5980cm -1 ) in BSA than HSA (Stokes'shift~6600cm -1 ), indicating less polar and more hydrophobic environment of the dye in the former than the latter. The dye-protein binding interactions are remarkably stronger for BSA than HSA which is evident from higher value of the association constant for the DMOBA-BSA complex (K a ~5.2×10 6 M -1 ) than the DMOBA-HSA complex (K a ~1.0×10 6 M -1 ). Fӧrster resonance energy transfer studies revealed remarkably less efficient energy transfer (8%) between the donor tryptophans in BSA and the acceptor DMOBA dye than that (30%) between the single tryptophan moiety in HSA and the dye, which is consistent with a much larger distance between the donor (tryptophan)-acceptor (dye) pair in BSA (34.5Å) than HSA (25.4Å). Site specific competitive binding assays have confirmed on the location of the dye in Sudlow's site II of BSA and in Sudlow's site I of HSA, respectively. Molecular modeling studies have shown that the fluorescent analogue is tightly packed in the binding site of BSA due to strong steric complementarity, where, binding of DMOBA to BSA is primarily dictated by the van der Waals and hydrogen bonding interactions. In contrast, in HSA the steric complementarity is less significant and binding is primarily guided by polar interactions and van der Waals interactions appear to be less significant in the formation of the HSA-DMOBA complex. Electrostatic interactions contribute significantly in the binding of DMOBA to HSA (-2.09kcal/mol) compared to BSA (-0.47kcal/mol). Electrostatic surface potential calculation reveals that the DMOBA binding site within HSA is highly charged compared to BSA. Copyright © 2016 Elsevier B.V. All rights reserved.

Dye sensitized photoelectrochemical immunosensor for the tumor marker CEA by using a flower-like 3D architecture prepared from graphene oxide and MoS2.

PubMed

Song, Kaijing; Ding, Chuanmin; Zhang, Bing; Chang, Honghong; Zhao, Zhihuan; Wei, Wenlong; Wang, Junwen

2018-06-01

The authors describe a dye-sensitized photoelectrochemical immunoassay for the tumor marker carcinoembryonic antigen (CEA). The method employs the rhodamine dye Rh123 with red color and absorption maximum at 500 nm for spectral sensitization, and a 3D nanocomposite prepared from graphene oxide and MoS 2 acting as the photoelectric conversion layer. The nanocomposite with flower-like 3D architectures was characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, and UV-vis diffuse reflectometry. A photoelectrochemical sandwich immunoassay was developed that is based on the use of the nanocomposite and based on the specific binding of antibody and antigen, and by using a secondary antibody labeled with Rh123 and CdS (Ab 2 -Rh123@CdS). Under optimal conditions and at a typical working voltage of 0 V (vs. Hg/HgCl 2 ), the photocurrent increases linearly 10 pg mL -1 to 80 ng mL -1 CEA concentration range, with a 3.2 pg mL -1 detection limit. Graphical abstract Flower-like GO-MoS 2 complex with high efficiency of electron transport was synthesized to construct photoelectrochemical platform. The sandwich-type immunoassay was built on this platform based on specific binding of antigen and antibody. Carcinoembryonic antigen in sample was detected sensitively by using sensitization of rhodamine dye Rh123 as signal amplification strategy.

Polyoxometalate-modified TiO2 nanotube arrays photoanode materials for enhanced dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Liu, Ran; Sun, Zhixia; Zhang, Yuzhuo; Xu, Lin; Li, Na

2017-10-01

In this work, we prepared for the first time the TiO2 nanotube arrays (TNAs) photoanode with polyoxometalate(POMs)-modified TiO2 electron-transport layer for improving the performance of zinc phthalocyanine(ZnPc)-sensitized solar cells. The as-prepared POMs/TNAs/ZnPc composite photoanode exhibited higher photovoltaic performances than the TNAs/ZnPc photoanode, so that the power conversion efficiency of the solar cell device based on the POMs/TNAs/ZnPc photoanode displayed a notable improvement of 45%. These results indicated that the POMs play a key role in reducing charge recombination in phthalocyanine-sensitized solar cells, together with TiO2 nanotube arrays being helpful for electron transport. The mechanism of the performance improvement was demonstrated by the measurements of electrochemical impedance spectra and open-circuit voltage decay curves. Although the resulting performance is still below that of the state-of-the-art dye-sensitized solar cells, this study presents a new insight into improving the power conversion efficiency of phthalocyanine-sensitized solar cells via polyoxometalate-modified TiO2 nanotube arrays photoanode.

Validation of a dye stain assay for vaginally inserted HEC-filled microbicide applicators

PubMed Central

Katzen, Lauren L.; Fernández-Romero, José A.; Sarna, Avina; Murugavel, Kailapuri G.; Gawarecki, Daniel; Zydowsky, Thomas M.; Mensch, Barbara S.

2011-01-01

Background The reliability and validity of self-reports of vaginal microbicide use are questionable given the explicit understanding that participants are expected to comply with study protocols. Our objective was to optimize the Population Council's previously validated dye stain assay (DSA) and related procedures, and establish predictive values for the DSA's ability to identify vaginally inserted single-use, low-density polyethylene microbicide applicators filled with hydroxyethylcellulose gel. Methods Applicators, inserted by 252 female sex workers enrolled in a microbicide feasibility study in Southern India, served as positive controls for optimization and validation experiments. Prior to validation, optimal dye concentration and staining time were ascertained. Three validation experiments were conducted to determine sensitivity, specificity, negative predictive values and positive predictive values. Results The dye concentration of 0.05% (w/v) FD&C Blue No. 1 Granular Food Dye and staining time of five seconds were determined to be optimal and were used for the three validation experiments. There were a total of 1,848 possible applicator readings across validation experiments; 1,703 (92.2%) applicator readings were correct. On average, the DSA performed with 90.6% sensitivity, 93.9% specificity, and had a negative predictive value of 93.8% and a positive predictive value of 91.0%. No statistically significant differences between experiments were noted. Conclusions The DSA was optimized and successfully validated for use with single-use, low-density polyethylene applicators filled with hydroxyethylcellulose (HEC) gel. We recommend including the DSA in future microbicide trials involving vaginal gels in order to identify participants who have low adherence to dosing regimens. In doing so, we can develop strategies to improve adherence as well as investigate the association between product use and efficacy. PMID:21992983

Role of charge separation mechanism and local disorder at hybrid solar cell interfaces

NASA Astrophysics Data System (ADS)

Ehrenreich, Philipp; Pfadler, Thomas; Paquin, Francis; Dion-Bertrand, Laura-Isabelle; Paré-Labrosse, Olivier; Silva, Carlos; Weickert, Jonas; Schmidt-Mende, Lukas

2015-01-01

Dye-sensitized metal oxide polymer hybrid solar cells deliver a promising basis in organic solar cell development due to many conceptual advantages. Since the power conversion efficiency is still in a noncompetitive state, it has to be understood how the photocurrent contribution can be maximized (i.e., which dye-polymer properties are most beneficial for efficient charge generation in hybrid solar cells). By the comparison of three model systems for hybrid solar cells with Ti O2 -dye-polymer interfaces, this paper was aimed at elucidating the role of the exact mechanism of charge generation. In the exciton dissociation (ED) case, an exciton that is generated in the polymer is split at the dye-polymer interface. Alternatively, this exciton can be transferred to the dye via an energy transfer (ET), upon which charge separation occurs between dye and Ti O2 . For comparison, the third case is included in which the high lowest unoccupied molecular orbital of the dye does not allow exciton separation or ET from the dye to the polymer, so that the dye only is responsible for charge generation. To separate effects owing to differences in energy levels of the involved materials from the impact of local order and disorder in the polymer close to the interface, this paper further comprises a detailed analysis of the polymer crystallinity based on the H-aggregate model. While the massive impact of the poly(3-hexylthiophene) crystallinity on device function has been outlined for bare metal oxide-polymer interfaces, it has not been considered for hybrid solar cells with dye-sensitized Ti O2 . The results presented here indicate that all dye molecules in general influence the polymer morphology, which has to be taken into account for future optimization of hybrid solar cells. Apart from that, it can be suggested that ED on the polymer needs an additional driving force to work efficiently; thus, energy transfer seems to be currently the most promising strategy to increase the polymer photocurrent contribution.

Does the position of the electron-donating nitrogen atom in the ring system influence the efficiency of a dye-sensitized solar cell? A computational study.

PubMed

Biswas, Abul Kalam; Barik, Sunirmal; Das, Amitava; Ganguly, Bishwajit

2016-06-01

We have reported a number of new metal-free organic dyes (2-6) that have cyclic asymmetric benzotripyrrole derivatives as donor groups with peripheral nitrogen atoms in the ring, fluorine and thiophene groups as π-spacers, and a cyanoacrylic acid acceptor group. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were employed to examine the influence of the position of the donor nitrogen atom and π-conjugation on solar cell performance. The calculated electron-injection driving force (ΔG inject), electron-regeneration driving force (ΔG regen), light-harvesting efficiency (LHE), dipole moment (μ normal), and number of electrons transferred (∆q) indicate that dyes 3, 4, and 6 have significantly higher efficiencies than reference dye 1, which exhibits high efficiency. We also extended our comparison to some other reported dyes, 7-9, which have a donor nitrogen atom in the middle of the ring system. The computed results suggest that dye 6 possesses a higher incident photon to current conversion efficiency (IPCE) than reported dyes 7-9. Thus, the use of donor groups with peripheral nitrogen atoms appears to lead to more efficient dyes than those in which the nitrogen atom is present in the middle of the donor ring system. Graphical Abstract The locations of the nitrogen atoms in the donor groups in the designed dye molecules have an important influence on DSSC efficiency.

Dyes removal using activated carbon from palm oil waste with digital image colorimetry quantification

NASA Astrophysics Data System (ADS)

Firdaus, M. Lutfi; Puspita, Melfi; Alwi, Wiwit; Ghufira, Nurhamidah, Elvia, Rina

2017-11-01

In the present study, activated carbon prepared from palm oil husk was used as adsorbent to remove synthetic dyes of Reactive Red 120 (RR) and Direct Green 26 (DG) from aqueous solution. The effects of solution pH, contact time, adsorbent weight, dyes concentration, and temperature on adsorption were evaluated based on batch experiments along with determination of the adsorption isotherms, kinetics, and thermodynamics parameters. Visible spectrophotometry was used for the quantification of dyes concentration, in conjunction with digital image colorimetry as a novel quantification method. Compared to visible spectrophotometry, the results of digital image colorimetry were accurate. In addition, improved sensitivity was achieved using this new colorimetry method. At equilibrium, dyes adsorption onto activated carbon followed Freundlich model, with adsorption capacities for RR and DG were 32 and 27 mg/g, respectively. The adsorption kinetics study showed a pseudo-second-order model with thermodynamic parameters of ΔG°, ΔH°, and ΔS° were -1.8 to -3.8 kJ/mol, -13.5 to -24.38 kJ/mol, and 0.001 J/mol, respectively. Therefore, the process of adsorption was exothermic and spontaneous with an increase in the disorder or entropy of the system.

Use of the dye stain assay and ultraviolet light test for assessing vaginal insertion of placebo-filled applicators before and after sex.

PubMed

Keller, Marla J; Buckley, Niall; Katzen, Lauren L; Walsh, Jennifer; Friedland, Barbara; Littlefield, Sarah; Lin, Juan; Xue, Xiaonan; Cornelison, Terri; Herold, Betsy C; Einstein, Mark H

2013-12-01

Applicator dye staining and ultraviolet (UV) light have been used in trials to measure adherence, but not in the setting of before and after sex gel dosing (BAT-24). This study was designed to determine if semen or presex gel dosing impacts the sensitivity and specificity of a dye stain assay (DSA) for measuring vaginal insertion of placebo-filled applicators with BAT-24 dosing. Healthy monogamous couples received Microlax-type applicators (Tectubes, Åstorp, Sweden) filled with hydroxyethylcelluose placebo gel. Women were instructed to vaginally insert 1 dose of gel before and a second dose after sex and to return applicators within 48 hours after sex. Applicators were stained to detect semen, followed by UV then DSA, and scored by 2 readers. Positive and negative controls were randomly included in applicator batches. Fifteen couples completed the study. Each woman returned at least 6 applicators over a 30-day period. The sensitivity for insertion of postsex applicators was higher for UV (97%) compared with DSA (90%), and the specificity was similar (≥96%). For presex applicators, the sensitivity and specificity were higher for DSA (100%) compared with UV testing (87% sensitivity, 96% specificity). Among returned postsex applicators, 95% tested positive by UV compared with 87% by DSA. Agreement between readers was significantly better on the presex applicators for DSA than for UV, and for postsex readings, agreement was less than half that for UV, although the results were not statistically significant. Applicator tests are feasible for measuring adherence in trials with gel dosing before and after sex.

A luminescent Lanthanide-free MOF nanohybrid for highly sensitive ratiometric temperature sensing in physiological range.

PubMed

Zhou, You; Zhang, Denan; Zeng, Jin; Gan, Ning; Cuan, Jing

2018-05-01

Luminescent MOF materials with tunable emissions and energy/charge transfer processes have been extensively explored as ratiometric temperature sensors. However, most of the ratiometric MOF thermometers reported thus far are based on the MOFs containing photoactive lanthanides, which are potentially facing cost issue and serious supply shortage. Here, we present a ratiometric luminescent thermometer based on a dual-emitting lanthanide-free MOF hybrid, which is developed by encapsulation of a fluorescent dye into a robust nanocrystalline zirconium-based MOF through a one-pot synthesis approach. The structure and morphology of the hybrid product was characterized by Powder X-ray diffraction (PXRD), N 2 adsorption-desorption measurement and Scanning electron microscopy (SEM). The pore confinement effect well isolates the guest dye molecules and therefore suppresses the nonradiative energy transfer process between dye molecules. The incorporated dye emission is mainly sensitized by the organic linkers within MOF through fluorescence resonance energy transfer. The ratiometric luminescence of the MOF hybrid shows a significant response to temperature due to the thermal-related back energy transfer process from dye molecules and organic linkers, thus can be exploited for self-calibrated temperature sensing. The maximum thermometric sensitivity is 1.19% °C -1 in the physiological temperature range, which is among the highest for the ratiomtric MOF thermometers that operating in 25-45°C. The temperature resolution is better than 0.1°C over the entire operative range (20-60°C). By integrating the advantages of excellent stability, nanoscale nature, and high sensitivity and precision in the physiological temperature range, this dye@MOF hybrid might have potential application in biomedical diagnosis. What' more, this work has expanded the possibility of non-lanthanide luminescent MOF materials for the development of ratiometric temperature sensors. Copyright © 2018 Elsevier B.V. All rights reserved.

In vitro characterization of cutaneous immunotoxicity of immortalized human keratinocytes (HaCaT) exposed to reactive and disperse textile dyes.

PubMed

Leme, Daniela Morais; Sehr, Andrea; Grummt, Tamara; Gonçalves, Jenifer Pendiuk; Jacomasso, Thiago; Winnischofer, Sheila Maria Brochado; Potrich, Francine Bittencourt; Oliveira, Carolina Camargo de; Trindade, Edvaldo da Silva; de Oliveira, Danielle Palma

2018-05-01

Several synthetic dyes are used by textile industry for supplying the market of colored clothes. However, these chemicals have been associated with a variety of adverse human health effects, including textile dermatitis. Thus, there is a growing concern to identify textile dyes potentially as skin immunotoxicants. The aim of this in vitro study was to characterize the immunotoxic potential of reactive (Reactive Green 19 [RG19], Reactive Blue 2 [RB2], Reactive Black 5 [RB5]) and disperse (Disperse Red 1 [DR1]) textile dyes using a dermal cell line. For this purpose, a cell-based approach was conducted with immortalized human keratinocytes (KC) (HaCaT) using selected biomarkers of cutaneous inflammation including modulation of matrix metalloproteinases (MMP), oxidative stress such as reactive oxygen species (ROS) generation, and inflammatory cytokine profile. DR1 was the only dye able to trigger an immune response such as release of IL-12 cytokine, a potent co-stimulator of T helper 1 cell, which may be considered as a skin immunotoxicant. The reactive dyes including RB5 that were previously reported as skin sensitizers failed to induce inflammatory reactions under the conditions tested. The reactive dyes studied may pose a risk to human KC by induction of effects related to modulation of MMP-2 (RB5) and -9 (RB5 and RB2) and generation of ROS (RG19 and RB2). Thus, all these dyes need to be used with caution to avoid undesirable effects to consumers who may be exposed dermally.

Synthesis, Spectrofluorometric Studies, Micellization and non Linear Optical Properties of Blue Emitting Quinoline (AMQC) Dye.

PubMed

Afzal, S M; Asiri, Abdullah M; Razvi, M A N; Bakry, Ahmed H; Khan, Salman A; Zayed, Mohie E M

2016-03-01

Blue emitting 2-amino-4-(3, 4, 5-tri methoxyphenyl)-9-methoxy-5,6 dihydrobenzo[f]isoquinoline-1-carbonitrile (AMQC) dye was synthesized by one-pot multicomponent reactions (MCRs) of 3,4,5-trimethoxybenzaldehyd, malononitrile, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one and ammonium acetate. Results obtained from spectroscopic and elemental analysis of synthesized AMQC was in good agreement with their chemical structures. Fluorescence polarity study demonstrated that AMQC was sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including electronic absorption, excitation coefficient, stokes shift, oscillator strength, transition dipole moment and fluorescence quantum yield were investigated in order to explore the analytical potential of AMQC. Dye undergoes solubilization in different micelles and may be used as a quencher and a probe to determine the critical micelle concentration (CMC) of SDS and CTAB. Nonlinear optical parameters of AMQC dye shows relatively lower nonlinear refractive index and nonlinear absorption coefficient at the power levels. Variation of n2 with concentration is linear in the concentration range used in the present study.

In vivo tumor-targeted dual-modal fluorescence/CT imaging using a nanoprobe co-loaded with an aggregation-induced emission dye and gold nanoparticles.

PubMed

Zhang, Jimei; Li, Chan; Zhang, Xu; Huo, Shuaidong; Jin, Shubin; An, Fei-Fei; Wang, Xiaodan; Xue, Xiangdong; Okeke, C I; Duan, Guiyun; Guo, Fengguang; Zhang, Xiaohong; Hao, Jifu; Wang, Paul C; Zhang, Jinchao; Liang, Xing-Jie

2015-02-01

As an intensely studied computed tomography (CT) contrast agent, gold nanoparticle has been suggested to be combined with fluorescence imaging modality to offset the low sensitivity of CT. However, the strong quenching of gold nanoparticle on fluorescent dyes requires complicated design and shielding to overcome. Herein, we report a unique nanoprobe (M-NPAPF-Au) co-loading an aggregation-induced emission (AIE) red dye and gold nanoparticles into DSPE-PEG(2000) micelles for dual-modal fluorescence/CT imaging. The nanoprobe was prepared based on a facile method of "one-pot ultrasonic emulsification". Surprisingly, in the micelles system, fluorescence dye (NPAPF) efficiently overcame the strong fluorescence quenching of shielding-free gold nanoparticles and retained the crucial AIE feature. In vivo studies demonstrated the nanoprobe had superior tumor-targeting ability, excellent fluorescence and CT imaging effects. The totality of present studies clearly indicates the significant potential application of M-NPAPF-Au as a dual-modal non-invasive fluorescence/X-ray CT nanoprobe for in vivo tumor-targeted imaging and diagnosis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electronic structure of the indium tin oxide/nanocrystalline anatase (TiO2)/ruthenium-dye interfaces in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Lyon, J. E.; Rayan, M. K.; Beerbom, M. M.; Schlaf, R.

2008-10-01

The electronic structure of two interfaces commonly found in dye-sensitized photovoltaic cells based on nanocrystalline anatase TiO2 ("Grätzel cells") was investigated using photoemission spectroscopy (PES). X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS) measurements were carried out on the indium tin oxide (ITO)/TiO2 and the TiO2/cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)-ruthenium(II)bis-tetrabutylammonium dye ("N719" or "Ruthenium 535-bisTBA") interfaces. Both contacts were investigated using a multistep deposition procedure where the entire structure was prepared in vacuum using electrospray deposition. In between deposition steps the surface was characterized with XPS and UPS resulting in a series of spectra, allowing the determination of the orbital and band lineup at the interfaces. The results of these efforts confirm previous PES measurements on TiO2/dye contacts prepared under ambient conditions, suggesting that ambient contamination might not have significant influence on the electronic structure at the dye/TiO2 interface. The results also demonstrate that there may be a significant barrier for electron injection at the sputtered ITO/TiO2 interface and that this interface should be viewed as a semiconductor heterojunction rather than as metal-semiconductor (Schottky) contact.

Detection and identification of dyes in blue writing inks by LC-DAD-orbitrap MS.

PubMed

Sun, Qiran; Luo, Yiwen; Yang, Xu; Xiang, Ping; Shen, Min

2016-04-01

In the field of forensic questioned document examination, to identify dyes detected in inks not only provides a solid foundation for ink discrimination in forged contents identification, but also facilitates the investigation of ink origin or the study regarding ink dating. To detect and identify potential acid and basic dyes in blue writing inks, a liquid chromatography-diode array detection-Orbitrap mass spectrometry (LC-DAD-Orbitrap MS) method was established. Three sulfonic acid dyes (Acid blue 1, Acid blue 9 and Acid red 52) and six triphenylmethane basic dyes (Ethyl violet, Crystal violet, Methyl violet 2B, Basic blue 7, Victoria blue B and Victoria blue R) were employed as reference dyes for method development. Determination of the nine dyes was validated to evaluate the instrument performance, and it turned out to be sensitive and stable enough for quantification. The method was then applied in the screening analysis of ten blue roller ball pen inks and twenty blue ballpoint pen inks. As a result, including TPR (a de-methylated product of Crystal violet), ten known dyes and four unknown dyes were detected in the inks. The latter were further identified as a de-methylated product of Victoria blue B, Acid blue 104, Acid violet 49 and Acid blue 90, through analyzing their characteristic precursor and product ions acquired by Orbitrap MS with good mass accuracy. The results showed that the established method is capable of detecting and identifying potential dyes in blue writing inks. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Determination of Spatial Distribution of Air Pollution by Dye Laser Measurement of Differential Absorption of Elastic Backscatter

NASA Technical Reports Server (NTRS)

Ahmed, S. A.; Gergely, J. S.

1973-01-01

This paper presents the results of an analytical study of a lidar system which uses tunable organic dye lasers to accurately determine spatial distribution of molecular air pollutants. Also described will be experimental work to date on simultaneous multiwavelength output dye laser sources for this system. Basically the scheme determines the concentration of air pollutants by measuring the differential absorption of an (at least) two wavelength lidar signal elastically backscattered by the atmosphere. Only relative measurements of the backscattered intensity at each of the two wavelengths, one on and one off the resonance absorption of the pollutant in question, are required. The various parameters of the scheme are examined and the component elements required for a system of this type discussed, with emphasis on the dye laser source. Potential advantages of simultaneous multiwavelength outputs are described. The use of correlation spectroscopy in this context is examined. Comparisons are also made for the use of infrared probing wavelengths and sources instead of dye lasers. Estimates of the sensitivity and accuracy of a practical dye laser system of this type, made for specific pollutants, snow it to have inherent advantages over other schemes for determining pollutant spatial distribution.

Size Effects in Dye-Sensitized TiO2 Clusters

NASA Astrophysics Data System (ADS)

Marom, Noa; Körzdörfer, Thomas; Ren, Xinguo; Tkatchenko, Alexandre; Chelikowsky, James

2014-03-01

The development of solar cells is driven by the need for clean and sustainable energy. Organic and dye sensitized cells are considered as promising technologies, particularly for large area, low cost applications. However, the efficiency of such cells is still far from the theoretical limit. Ab initio simulations may be used for computer-aided design of new materials and nano-structures for more efficient solar cells. It is essential to obtain an accurate description of the electronic structure, including the fundamental gaps and energy level alignment at the interfaces in the device active region. This requires going beyond ground-state DFT to the GW approximation. A recently developed GW method [PRB 86, 041110R (2012)] is applied to dye-sensitized TiO2 clusters [PRB 84, 245115 (2011)]. The effect of cluster size on the energy level alignment at the dye-TiO2 interface is discussed. With the increase in the TiO2 cluster size its gap narrows. The gap of the molecule attached to the cluster subsequently narrows due to screening. As a result, the energy level alignment at the interface changes in an unexpected way [Marom, Körzdörfer, Ren, Tkatchenko, Chelikowsky, to be published].

Studying ion exchange in solution and at biological membranes by FCS.

PubMed

Widengren, Jerker

2013-01-01

By FCS, a wide range of processes can be studied, covering time ranges from subnanoseconds to seconds. In principle, any process at equilibrium conditions can be measured, which reflects itself by a change in the detected fluorescence intensity. In this review, it is described how FCS and variants thereof can be used to monitor ion exchange, in solution and along biological membranes. Analyzing fluorescence fluctuations of ion-sensitive fluorophores by FCS offers selective advantages over other techniques for measuring local ion concentrations, and, in particular, for studying exchange kinetics of ions on a very local scale. This opens for several areas of application. The FCS approach was used to investigate fundamental aspects of proton exchange at and along biological membranes. The protonation relaxation rate, as measured by FCS for a pH-sensitive dye, can also provide information about local accessibility/interaction of a particular labeling site and conformational states of biomolecules, in a similar fashion as in a fluorescence quenching experiment. The same FCS concept can also be applied to ion exchange studies using other ion-sensitive fluorophores, and by use of dyes sensitive to other ambient conditions the concept can be extended also beyond ion exchange studies. Copyright © 2013 Elsevier Inc. All rights reserved.

Laser synthesized super-hydrophobic conducting carbon with broccoli-type morphology as a counter-electrode for dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Gokhale, Rohan; Agarkar, Shruti; Debgupta, Joyashish; Shinde, Deodatta; Lefez, Benoit; Banerjee, Abhik; Jog, Jyoti; More, Mahendra; Hannoyer, Beatrice; Ogale, Satishchandra

2012-10-01

A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode.A laser photochemical process is introduced to realize superhydrophobic conducting carbon coatings with broccoli-type hierarchical morphology for use as a metal-free counter electrode in a dye sensitized solar cell. The process involves pulsed excimer laser irradiation of a thin layer of liquid haloaromatic organic solvent o-dichlorobenzene (DCB). The coating reflects a carbon nanoparticle-self assembled and process-controlled morphology that yields solar to electric power conversion efficiency of 5.1% as opposed to 6.2% obtained with the conventional Pt-based electrode. Electronic supplementary information (ESI) available: Materials and equipment details, solar cell fabrication protocol, electrolyte spreading time measurement details, XPS spectra, electronic study, film adhesion test detailed analysis and field emission results. See DOI: 10.1039/c2nr32082g

CdS/CdSe quantum dots and ZnPc dye co-sensitized solar cells with Au nanoparticles/graphene oxide as efficient modified layer.

PubMed

Chen, Cong; Cheng, Yu; Jin, Junjie; Dai, Qilin; Song, Hongwei

2016-10-15

Co-sensitization by using two or more sensitizers with complementary absorption spectra to expand the spectral response range is an effective approach to enhance device performance of quantum dot sensitized solar cells (QDSSCs). To improve the light-harvesting in the visible/near-infrared (NIR) region, organic dye zinc phthalocyanine (ZnPc) was combined with CdS/CdSe quantum dots (QDs) for co-sensitized solar cells based on ZnO inverse opals (IOs) as photoanode. The resulting co-sensitized device shows an efficient panchromatic spectral response feature to ∼750nm and presents an overall conversion efficiency of 4.01%, which is superior to that of the individual ZnPc-sensitized solar cells and CdS/CdSe-sensitized solar cells. Meanwhile, an Au nanoparticles/graphene oxide (Au NPs/GO) composite layer was successfully prepared to modify Cu2S counter electrode for the co-sensitized solar cells. Reducing the carrier recombination process by GO and catalytic process of Au NPs leads to increased power conversion efficiency(PCE) from 4.01 to 4.60% and sustainable stability remains ∼85% of its original value after 60min light exposure. In this paper, introduction of the organic dyes as co-sensitizer and Au NPs/GO as counter electrode modified layer has been proved to be an effective route to improve the performance of QDSSCs. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of nano anatase-rutile TiO2 volume fraction with natural dye containing anthocyanin on the dye sensitized solar cell performance

NASA Astrophysics Data System (ADS)

Agustini, S.; Wahyuono, R. A.; Sawitri, D.; Risanti, D. D.

2013-09-01

Since its first development, efforts to improve efficiency of Dye Sensitized Solar Cell (DSSC) are continuously carried out, either through selection of dye materials, the type of semiconductor, counter electrode design or the sandwiched structure. It is widely known that anatase and rutile are phases of TiO2 that often being used for fabrication of DSSC. Rutile is thermodynamically more stable phase having band-gap suitable for absorption of sunlight spectrum. On the other hand, anatase has higher electrical conductivity, capability to adsorp dye as well as higher electron diffusion coefficient than those of rutile. Present research uses mangosteen pericarp and Rhoeo spathacea extracted in ethanol as natural dye containing anthocyanin. These dyes were characterized by using UV-Vis and FTIR, showing that the absorption maxima peaks obtained at 389 nm and 413 nm, for mangosteen and Rhoeo spathacea, respectively. The nano TiO2 was prepared by means of co-precipitation method. The particle size were 9-11 nm and 54.5 nm for anatase and rutile, respectively, according to Scherrer's equation. DSSCs were fabricated in various volume fractions of anatase and rutile TiO2. The fabricated DSSCs were tested under 17 mW/cm2 of solar irradiation. The current-voltage (I-V) characteristic of DSSCs employing 75%: 25% volume fraction of anatase and rutile TiO2 have outstanding result than others. The highest conversion efficiencies of 0.037% and 0.013% are obtained for DSSC employing natural dye extract from mangosteen pericarp and Rhoeo spathacea, respectively.

Fundamental Investigations into the Infrared Properties of Carbon Nanotubes

DTIC Science & Technology

2013-01-23

Judy Wu. Development of Nanopatterned Fluorine-Doped Tin Oxide Electrodes for Dye-Sensitized Solar Cells with Improved Light Trapping, ACS Applied...heterojunction solar cell photocurrent enhancement, Nanoscale, (06 2012): 0. doi: 10.1039/c2nr30735a 08/30/2011 1.00 Rongtao Lu, Rayyan Kamal, Judy Z Wu...Jun Li, Judy Wu. The effect of annealing on the photoconductivity of carbon nanofiber/TiO2core-shell nanowires for use in dye-sensitized solar cells

An anionic Na(i)-organic framework platform: separation of organic dyes and post-modification for highly sensitive detection of picric acid.

PubMed

Chen, Di-Ming; Tian, Jia-Yue; Wang, Zhuo-Wei; Liu, Chun-Sen; Chen, Min; Du, Miao

2017-09-26

A cage-based anionic Na(i)-organic framework with a unique Na 9 cluster-based secondary building unit and a cage-in-cage structure was constructed. The selective separation of dyes with different charges and sizes was investigated. Furthermore, the Rh6G@MOF composite could be applied as a recyclable fluorescent sensor for detecting picric acid (PA) with high sensitivity and selectivity.

Microstructure characterization of onion (A.cepa) peels and thin films for dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Abodunrin, T.; Boyo, A.; Usikalu, M.; Obafemi, L.; Oladapo, O.; Kotsedi, L.; Yenus, Z.; Maaza, M.

2017-03-01

A.cepa peels are obtained from mature onion bulbs. Because of the continuous need for energy, alternative avenues for producing energy are gaining importance. The motivation for this work is based on an urgent need to source energy from readily available waste materials like domestic onion peels. Dye sensitized solar cells (DSSCs) fabricated via doctor blade method and high temperature sintering from waste (onion peels) are investigated for their ability to convert solar to electrical energy. The charge carriers were revealed under phytochemical screening. Functional groups of compounds present in A.cepa peel were analyzed with Fourier transform in infrared (FTIR). The influence of different electrolyte sensitizer is observed on the DSSCs under standard air mass conditions of 1.5 AM. The microstructure properties of these A.cepa DSSCs were explored using scanning electron microscope with energy dispersive spectroscopy (SEM/EDS), x-ray diffraction and Fluorecence spectroscopy (XRF). The interfacial boundary between A.cepa dye, TiO2 framework of TiO2 and indium doped tin oxide (ITO) reveals several prominent anatase and rutile peaks. Photoelectric results, revealed dye-sensitized solar cells with a maximum power output of 126 W and incident photon to conversion energy (IPCE) of 0.13%.This work has established that A.cepa peels can be used as a source of micro-energy generation.

Curcumin-sensitized TiO2 for enhanced photodegradation of dyes under visible light

NASA Astrophysics Data System (ADS)

Buddee, Supat; Wongnawa, Sumpun; Sriprang, Pimpaporn; Sriwong, Chaval

2014-04-01

Curcumin was coated on P25 TiO2 by using impregnation method from freshly prepared curcumin solution. The resulting products (Cur-TiO2-P25) was studied by several techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier-transformed infrared spectroscopy, specific surface area by the Brunauer-Emmett-Teller method, and UV-Vis diffused reflectance spectroscopy. Experimental results revealed that impregnation of curcumin at 0.5, 3, 5, and 7 wt% did not affect the native phase of anatase and rutile in P25 significantly, however, it caused red shift of absorption onset in all curcumin-coated samples. The Cur-TiO2-P25 showed enhanced adsorption efficiency and increased photocatalytic activity under visible light with optimal result at 5 wt% curcumin content. Commercial anatase and rutile coated with curcumin (Cur-TiO2-an and Cur-TiO2-ru) were also prepared by the same method for the use in comparative studies of photodegradation of dyes. Cur-TiO2-an and Cur-TiO2-ru were also characterized with some selected equipment above but not as extensively as the Cur-TiO2-P25. Curcumin coating helped improve photocatalytic efficiencies of P25 and anatase but not for rutile. The mechanism of photocatalytic reaction was proposed that under visible light irradiation, curcumin molecule could act as dye sensitizing agent that injected electron into the conduction band of TiO2 leading to photodegradation of dyes.

Co-encapsulation of enzyme and sensitive dye as a tool for fabrication of microcapsule based sensor for urea measuring.

PubMed

Kazakova, Lyubov I; Shabarchina, Lyudmila I; Sukhorukov, Gleb B

2011-06-21

Enzyme based micron sized sensing system with optical readout was fabricated by co-encapsulation of urease and dextran couple with pH sensitive dye SNARF-1 into polyelectrolyte multilayer capsules. Co-precipitation of calcium carbonate, urease and dextran followed up by multilayer film coating and Ca-extracting by EDTA resulted in the formation of 3.5-4 micron capsules, what enable the calibrated fluorescence response to urea in concentration range from 10(-6) to 10(-1) M. The presence of urea can be monitored on a single capsule level as illustrated by confocal fluorescent microscopy. Variations in urease:dye ratio in capsules, applicability and limits of use of that type multi-component microencapsulated sensors are discussed.

Chitosan-edible oil based materials as upgraded adsorbents for textile dyes.

PubMed

Dos Santos, Clayane Carvalho; Mouta, Rodolpho; Junior, Manoel Carvalho Castro; Santana, Sirlane Aparecida Abreu; Silva, Hildo Antonio Dos Santos; Bezerra, Cícero Wellington Brito

2018-01-15

Biopolymer chitosan is a low cost, abundant, environmentally friendly, very selective and efficient anionic dyes adsorbent, being a promising material for large-scale removal of dyes from wastewater. However, raw chitosan (CS) is an ineffective cationic dyes adsorbent and its performance is pH sensitive, thus, CS modifications that address these issues need to be developed. Here, we report the preparation and characterization of two new CS modifications using edible oils (soybean oil or babassu oil), and their adsorption performance for two dyes, one anionic (remazol red, RR) and one cationic (methylene blue, MB). Both modifications extended the pH range of RR adsorption. The babassu oil modification increased adsorption capacity of the cationic dye MB, whereas the soybean oil modification increased that of RR. Such improvements demonstrate the potential of these two new CS modifications as adsorbent candidates for controlling dyes pollution in effluents. Copyright © 2017 Elsevier Ltd. All rights reserved.

High-sensitivity detection of biological amines using fast Hadamard transform CE coupled with photolytic optical gating.

PubMed

Braun, Kevin L; Hapuarachchi, Suminda; Fernandez, Facundo M; Aspinwall, Craig A

2007-08-01

Here, we report the first utilization of Hadamard transform CE (HTCE), a high-sensitivity, multiplexed CE technique, with photolytic optical gating sample injection of caged fluorescent labels for the detection of biologically important amines. Previous implementations of HTCE have relied upon photobleaching optical gating sample injection of fluorescent dyes. Photolysis of caged fluorescent labels reduces the fluorescence background, providing marked enhancements in sensitivity compared to photobleaching. Application of fast Hadamard transform CE (fHTCE) for fluorescein-based dyes yields a ten-fold higher sensitivity for photolytic injections compared to photobleaching injections, due primarily to the reduced fluorescent background provided by caged fluorescent dyes. Detection limits as low as 5 pM (ca. 18 molecules per injection event) were obtained with on-column LIF detection using fHTCE in less than 25 s, with the capacity for continuous, online separations. Detection limits for glutamate and aspartate below 150 pM (1-2 amol/injection event) were obtained using photolytic sample injection, with separation efficiencies exceeding 1 x 10(6) plates/m and total multiplexed separation times as low as 8 s. These results strongly support the feasibility of this approach for high-sensitivity dynamic chemical monitoring applications.

Unravelling the structural-electronic impact of arylamine electron-donating antennas on the performances of efficient ruthenium sensitizers for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Chen, Wang-Chao; Kong, Fan-Tai; Ghadari, Rahim; Li, Zhao-Qian; Guo, Fu-Ling; Liu, Xue-Peng; Huang, Yang; Yu, Ting; Hayat, Tasawar; Dai, Song-Yuan

2017-04-01

We report a systematic research to understand the structural-electronic impact of the arylamine electron-donating antennas on the performances of the ruthenium complexes for dye-sensitized solar cells. Three ruthenium complexes functionalized with different arylamine electron-donating antennas (N,N-diethyl-aniline in RC-31, julolidine in RC-32 and N,N-dibenzyl-aniline in RC-36) are designed and synthesized. The photoelectric properties of RC dyes exhibit apparent discrepancy, which are ascribed to different structural nature and electronic delocalization ability of these arylamine electron-donating system. In conjunction with TiO2 microspheres photoanode and a typical coadsorbent DPA, the devices sensitized by RC-36 achieve the best conversion efficiency of 10.23%. The UV-Vis absorption, electrochemical measurement, incident photon-to-current conversion efficiency and transient absorption spectra confirm that the excellent performance of RC-36 is induced by synergistically structural-electronic impacts from enhanced absorption capacity and well-tuned electronic characteristics. These observations provide valuable insights into the molecular engineering methodology based on fine tuning structural-electronic impact of electron-donating antenna in efficient ruthenium sensitizers.

Self-assembled ultra small ZnO nanocrystals for dye-sensitized solar cell application

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

Patra, Astam K.; Dutta, Arghya; Bhaumik, Asim, E-mail: msab@iacs.res.in

2014-07-01

We demonstrate a facile chemical approach to produce self-assembled ultra-small mesoporous zinc oxide nanocrystals using sodium salicylate (SS) as a template under hydrothermal conditions. These ZnO nanomaterials have been successfully fabricated as a photoanode for the dye-sensitized solar cell (DSSC) in the presence of N719 dye and iodine–triiodide electrolyte. The structural features, crystallinity, purity, mesophase and morphology of the nanostructure ZnO are investigated by several characterization tools. N{sub 2} sorption analysis revealed high surface areas (203 m{sup 2} g{sup −1}) and narrow pore size distributions (5.1–5.4 nm) for different samples. The mesoporous structure and strong photoluminescence facilitates the high dyemore » loading at the mesoscopic void spaces and light harvesting in DSSC. By utilizing this ultra-small ZnO photoelectrode with film thickness of about 7 μm in the DSSC with an open-circuit voltage (V{sub OC}) of 0.74 V, short-circuit current density (J{sub SC}) of 3.83 mA cm{sup −2} and an overall power conversion efficiency of 1.12% has been achieved. - Graphical abstract: Ultra-small ZnO nanocrystals have been synthesized with sodium salicylate as a template and using it as a photoanode in a dye-sensitized solar cell 1.12% power conversion efficiency has been observed. - Highlights: • Synthesis of self-assembled ultra-small mesoporous ZnO nanocrystals by using sodium salicylate as a template. • Mesoporous ZnO materials have high BET surface areas and void space. • ZnO nanoparticles serve as a photoanode for the dye-sensitized solar cell (DSSC). • Using ZnO nanocrystals as photoelectrode power conversion efficiency of 1.12% has been achieved.« less

Performance of Dye-Sensitized Solar Cells (DSSCs) Fabricated with Zinc Oxide (ZnO) Nanpowders and Nanorods

NASA Astrophysics Data System (ADS)

Chatterjee, Suman

2018-03-01

Due to their high efficiencies, along with lower production costs, many researchers are working on dye-sensitized solar cells (DSSCs) over last few decades as a substitute technology for nonconventional energy. Nanostructured ZnO has got many interesting properties such as wide band gap, large exciton binding energy, good exciton stability, and high breakdown strength, which are applicable as DSSC electrodes. This present work compares the device properties of DSSC fabricated using ZnO nanorods on a ZnO film and ZnO nanopowders. Different types of ZnO photoanode and dye combinations are used to study the stability and photovoltaic properties of the DSSC cell. The photovoltaic properties of the ZnO-based DSSC samples were systematically investigated. The photovoltaic properties of fabricated cell obtained are discussed in the light of band structure and density of states of different types of ZnO nanolayers. The ZnO nanorods fabricated through the sol-gel route have more uniform thickness resulting in enhanced photovoltaic properties of the fabricated device.

Organic and Inorganic Dyes in Polyelectrolyte Multilayer Films

PubMed Central

Ball, Vincent

2012-01-01

Polyelectrolyte multilayer films are a versatile functionalization method of surfaces and rely on the alternated adsorption of oppositely charged species. Among such species, charged dyes can also be alternated with oppositely charged polymers, which is challenging from a fundamental point of view, because polyelectrolytes require a minimal number of charges, whereas even monovalent dyes can be incorporated during the alternated adsorption process. We will not only focus on organic dyes but also on their inorganic counterparts and on metal complexes. Such films offer plenty of possible applications in dye sensitized solar cells. In addition, dyes are massively used in the textile industry and in histology to stain textile fibers or tissues. However, the excess of non bound dyes poses serious environmental problems. It is hence of the highest interest to design materials able to adsorb such dyes in an almost irreversible manner. Polyelectrolyte multilayer films, owing to their ion exchange behavior can be useful for such a task allowing for impressive overconcentration of dyes with respect to the dye in solution. The actual state of knowledge of the interactions between charged dyes and adsorbed polyelectrolytes is the focus of this review article.

Reactively sputtered nickel nitride as electrocatalytic counter electrode for dye- and quantum dot-sensitized solar cells

NASA Astrophysics Data System (ADS)

Soo Kang, Jin; Park, Min-Ah; Kim, Jae-Yup; Ha Park, Sun; Young Chung, Dong; Yu, Seung-Ho; Kim, Jin; Park, Jongwoo; Choi, Jung-Woo; Jae Lee, Kyung; Jeong, Juwon; Jae Ko, Min; Ahn, Kwang-Soon; Sung, Yung-Eun

2015-05-01

Nickel nitride electrodes were prepared by reactive sputtering of nickel under a N2 atmosphere at room temperature for application in mesoscopic dye- or quantum dot- sensitized solar cells. This facile and reliable method led to the formation of a Ni2N film with a cauliflower-like nanostructure and tetrahedral crystal lattice. The prepared nickel nitride electrodes exhibited an excellent chemical stability toward both iodide and polysulfide redox electrolytes. Compared to conventional Pt electrodes, the nickel nitride electrodes showed an inferior electrocatalytic activity for the iodide redox electrolyte; however, it displayed a considerably superior electrocatalytic activity for the polysulfide redox electrolyte. As a result, compared to dye-sensitized solar cells (DSCs), with a conversion efficiency (η) = 7.62%, and CdSe-based quantum dot-sensitized solar cells (QDSCs, η = 2.01%) employing Pt counter electrodes (CEs), the nickel nitride CEs exhibited a lower conversion efficiency (η = 3.75%) when applied to DSCs, but an enhanced conversion efficiency (η = 2.80%) when applied to CdSe-based QDSCs.

Insight into D-A-π-A Structured Sensitizers: A Promising Route to Highly Efficient and Stable Dye-Sensitized Solar Cells.

PubMed

Wu, Yongzhen; Zhu, Wei-Hong; Zakeeruddin, Shaik M; Grätzel, Michael

2015-05-13

The dye-sensitized solar cell (DSSC) is one of the most promising photovoltaic technologies with potential of low cost, light weight, and good flexibility. The practical application of DSSCs requires further improvement in power conversion efficiency and long-term stability. Recently, significant progress has been witnessed in DSSC research owing to the novel concept of the D-A-π-A motif for the molecular engineering of organic photosensitizers. New organic and porphyrin dyes based on the D-A-π-A motif can not only enhance photovoltaic performance, but also improve durability in DSSC applications. This Spotlight on Applications highlights recent advances in the D-A-π-A-based photosensitizers, specifically focusing on the mechanism of efficiency and stability enhancements. Also, we find insight into the additional acceptor as well as the trade-off of long wavelength response. The basic principles are involved in molecular engineering of efficient D-A-π-A sensitizers, providing a clear road map showing how to modulate the energy bands, rationally extending the response wavelength, and optimizing photovoltaic efficiency step by step.

Co-sensitization of ZnO by CdS quantum dots in natural dye-sensitized solar cells with polymeric electrolytes to improve the cell stability

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

Junhom, W.; Magaraphan, R.

2015-05-22

The CdS quantum dots (QDs) were deposited on ZnO layer by chemical bath deposition method to absorb light in the shorter wavelength region and used as photoanode in the dye sensitized solar cell (DSSCs) with natural dye extracted from Noni leaves. Microstructures of CdS-ZnO from various dipping time were characterized by XRD, FE-SEM and EDX. The results showed that the CdS is hexagonal structure and the amount of CdS increases when the dipping time increases. The maximal conversion efficiency of 0.292% was achieved by the DSSCs based on CdS QDs-sensitized ZnO film obtained from 9 min-dipping time. Furthermore, the stability ofmore » DSSCs was improved by using polymeric electrolyte. Poly (acrylic acid) (PAA) and Polyacrylamide (PAM) were introduced to CdS QDs-sensitized ZnO film from 9 min-dipping time. Each polymeric electrolyte was prepared by swelling from 0.1-2.0 %w in H2O. The maximal conversion efficiency of 0.207% was achieved for DSSCs based on CdS QDs-sensitized ZnO film with PAM 1.0% and the conversion efficiency was decreased 25% when it was left for1 hr.« less

Co-sensitization of ZnO by CdS quantum dots in natural dye-sensitized solar cells with polymeric electrolytes to improve the cell stability

NASA Astrophysics Data System (ADS)

Junhom, W.; Magaraphan, R.

2015-05-01

The CdS quantum dots (QDs) were deposited on ZnO layer by chemical bath deposition method to absorb light in the shorter wavelength region and used as photoanode in the dye sensitized solar cell (DSSCs) with natural dye extracted from Noni leaves. Microstructures of CdS-ZnO from various dipping time were characterized by XRD, FE-SEM and EDX. The results showed that the CdS is hexagonal structure and the amount of CdS increases when the dipping time increases. The maximal conversion efficiency of 0.292% was achieved by the DSSCs based on CdS QDs-sensitized ZnO film obtained from 9 min-dipping time. Furthermore, the stability of DSSCs was improved by using polymeric electrolyte. Poly (acrylic acid) (PAA) and Polyacrylamide (PAM) were introduced to CdS QDs-sensitized ZnO film from 9 min-dipping time. Each polymeric electrolyte was prepared by swelling from 0.1-2.0 %w in H2O. The maximal conversion efficiency of 0.207% was achieved for DSSCs based on CdS QDs-sensitized ZnO film with PAM 1.0% and the conversion efficiency was decreased 25% when it was left for1 hr.

Sentinel lymph node status in vulval cancer: systematic reviews of test accuracy and decision-analytic model-based economic evaluation.

PubMed

Meads, C; Sutton, A; Małysiak, S; Kowalska, M; Zapalska, A; Rogozinska, E; Baldwin, P; Rosenthal, A; Ganesan, R; Borowiack, E; Barton, P; Roberts, T; Sundar, S; Khan, K

2013-12-01

Vulval cancer causes 3-5% of all gynaecological malignancies and requires surgical removal and inguinofemoral lymphadenectomy (IFL). Complications affect > 50% of patients, including groin wound infection, lymphoedema and cellulitis. A sentinel lymph node (SLN) is the first groin node with the highest probability of malignancy. SLN biopsy would be useful if it could accurately identify patients in whom cancer has spread to the groin, without removing all groin nodes. SLNs can be identified by isosulfan blue dye and/or technetium-99 ((99m)Tc) radioactive tracer during lymphoscintigraphy. The blue dye/(99m)Tc procedure only detects SLN, not metastases - this requires histological examination, which can include ultrastaging and staining with conventional haematoxylin and eosin (H&E) or immunohistochemistry. To determine the test accuracy and cost-effectiveness of the SLN biopsy with (99m)Tc and/or blue dye compared with IFL or clinical follow-up for test negatives in vulval cancer, through systematic reviews and economic evaluation. Standard medical databases, including MEDLINE, EMBASE, Science Citation Index and The Cochrane Library, medical search gateways, reference lists of review articles and included studies were searched to January 2011. For accuracy and effectiveness, standard methods were used and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches were to January 2011, with no language restrictions. Meta-analyses were carried out with Meta-Disc version 1.4 (Javier Zamora, Madrid, Spain) for accuracy; none was appropriate for effectiveness. The economic evaluation from a NHS perspective used a decision-tree model in DATA TreeAge Pro Healthcare 2001 (TreeAge Software, Inc., Williamstown, MA, USA). Six options (blue dye with H&E, blue dye with ultrastaging, (99m)Tc with H&E, (99m)Tc with ultrastaging, blue dye/(99m)Tc with H&E, blue dye/(99m)Tc with ultrastaging) were compared with IFL. Deterministic and probabilistic sensitivity analyses were conducted. For accuracy, of the 26 included studies, most evaluated (99m)Tc/blue dye combined. Four studies had clinical follow-up only for test negatives and five had clinical follow-up for all and IFL for test negatives. Numbers with no SLN found were difficult to distinguish from those with negative SLN biopsies. The largest group of 11 studies using (99m)Tc/blue dye, ultrastaging and immunohistochemistry had a pooled sensitivity of 95.6% [95% confidence interval (CI) 91.5% to 98.1%] and a specificity of 100% (95% CI 99.0% to 100%). Mean SLN detection rates were 94.6% for (99m)Tc, 68.7% for blue dye and 97.7% for both. One study measured global health status quality of life (QoL) and found no difference between SLN biopsy and IFL. One patient preference evaluation showed that 66% preferred IFL rather than a 5% false-negative rate from SLN biopsy. For effectiveness, of 14,038 references, one randomised controlled trial, three case-control studies and 13 case series were found. Approximately 50% died from vulval cancer and 50% from other causes during follow-ups. Recurrences were in the ratio of approximately 4 : 2 : 1 vulval, groin and distant, with more recurrences in node-positive patients. No studies reported QoL. For cost per death averted, IFL was less costly and more effective than strategies using SLN biopsy. For morbidity-free survival and long-term morbidity-free survival, (99m)Tc with ultrastaging was most cost-effective. Strategies with blue dye only and H&E only were never cost-effective. The incremental cost-effectiveness ratio for (99m)Tc with ultrastaging compared with IFL was £4300 per case of morbidity-free survival and £7100 per long-term morbidity-free survival. The main limitations of this study include the lack of good-quality evidence on accuracy, effectiveness and QoL. A large project such as this takes time to publish, so the most recent studies are not included. A sensitive and specific combined metastatic SLN detection test and information on generic QoL in vulval cancer is urgently required. The National Institute for Health Research Health Technology Assessment programme.

A unique charge-coupled device/xenon arc lamp based imaging system for the accurate detection and quantitation of multicolour fluorescence.

PubMed

Spibey, C A; Jackson, P; Herick, K

2001-03-01

In recent years the use of fluorescent dyes in biological applications has dramatically increased. The continual improvement in the capabilities of these fluorescent dyes demands increasingly sensitive detection systems that provide accurate quantitation over a wide linear dynamic range. In the field of proteomics, the detection, quantitation and identification of very low abundance proteins are of extreme importance in understanding cellular processes. Therefore, the instrumentation used to acquire an image of such samples, for spot picking and identification by mass spectrometry, must be sensitive enough to be able, not only, to maximise the sensitivity and dynamic range of the staining dyes but, as importantly, adapt to the ever changing portfolio of fluorescent dyes as they become available. Just as the available fluorescent probes are improving and evolving so are the users application requirements. Therefore, the instrumentation chosen must be flexible to address and adapt to those changing needs. As a result, a highly competitive market for the supply and production of such dyes and the instrumentation for their detection and quantitation have emerged. The instrumentation currently available is based on either laser/photomultiplier tube (PMT) scanning or lamp/charge-coupled device (CCD) based mechanisms. This review briefly discusses the advantages and disadvantages of both System types for fluorescence imaging, gives a technical overview of CCD technology and describes in detail a unique xenon/are lamp CCD based instrument, from PerkinElmer Life Sciences. The Wallac-1442 ARTHUR is unique in its ability to scan both large areas at high resolution and give accurate selectable excitation over the whole of the UV/visible range. It operates by filtering both the excitation and emission wavelengths, providing optimal and accurate measurement and quantitation of virtually any available dye and allows excellent spectral resolution between different fluorophores. This flexibility and excitation accuracy is key to multicolour applications and future adaptation of the instrument to address the application requirements and newly emerging dyes.

Orientational dynamics and dye-DNA interactions in a dye-labeled DNA aptamer.

PubMed

Unruh, Jay R; Gokulrangan, Giridharan; Lushington, G H; Johnson, Carey K; Wilson, George S

2005-05-01

We report the picosecond and nanosecond timescale rotational dynamics of a dye-labeled DNA oligonucleotide or "aptamer" designed to bind specifically to immunoglobulin E. Rotational dynamics in combination with fluorescence lifetime measurements provide information about dye-DNA interactions. Comparison of Texas Red (TR), fluorescein, and tetramethylrhodamine (TAMRA)-labeled aptamers reveals surprising differences with significant implications for biophysical studies employing such conjugates. Time-resolved anisotropy studies demonstrate that the TR- and TAMRA-aptamer anisotropy decays are dominated by the overall rotation of the aptamer, whereas the fluorescein-aptamer anisotropy decay displays a subnanosecond rotational correlation time much shorter than that expected for the overall rotation of the aptamer. Docking and molecular dynamics simulations suggest that the low mobility of TR is a result of binding in the groove of the DNA helix. Additionally, associated anisotropy analysis of the TAMRA-aptamer reveals both quenched and unquenched states that experience significant coupling to the DNA motion. Therefore, quenching of TAMRA by guanosine must depend on the configuration of the dye bound to the DNA. The strong coupling of TR to the rotational dynamics of the DNA aptamer, together with the absence of quenching of its fluorescence by DNA, makes it a good probe of DNA orientational dynamics. The understanding of the nature of dye-DNA interactions provides the basis for the development of bioconjugates optimized for specific biophysical measurements and is important for the sensitivity of anisotropy-based DNA-protein interaction studies employing such conjugates.

Orientational Dynamics and Dye-DNA Interactions in a Dye-Labeled DNA Aptamer

PubMed Central

Unruh, Jay R.; Gokulrangan, Giridharan; Lushington, G. H.; Johnson, Carey K.; Wilson, George S.

2005-01-01

We report the picosecond and nanosecond timescale rotational dynamics of a dye-labeled DNA oligonucleotide or “aptamer” designed to bind specifically to immunoglobulin E. Rotational dynamics in combination with fluorescence lifetime measurements provide information about dye-DNA interactions. Comparison of Texas Red (TR), fluorescein, and tetramethylrhodamine (TAMRA)-labeled aptamers reveals surprising differences with significant implications for biophysical studies employing such conjugates. Time-resolved anisotropy studies demonstrate that the TR- and TAMRA-aptamer anisotropy decays are dominated by the overall rotation of the aptamer, whereas the fluorescein-aptamer anisotropy decay displays a subnanosecond rotational correlation time much shorter than that expected for the overall rotation of the aptamer. Docking and molecular dynamics simulations suggest that the low mobility of TR is a result of binding in the groove of the DNA helix. Additionally, associated anisotropy analysis of the TAMRA-aptamer reveals both quenched and unquenched states that experience significant coupling to the DNA motion. Therefore, quenching of TAMRA by guanosine must depend on the configuration of the dye bound to the DNA. The strong coupling of TR to the rotational dynamics of the DNA aptamer, together with the absence of quenching of its fluorescence by DNA, makes it a good probe of DNA orientational dynamics. The understanding of the nature of dye-DNA interactions provides the basis for the development of bioconjugates optimized for specific biophysical measurements and is important for the sensitivity of anisotropy-based DNA-protein interaction studies employing such conjugates. PMID:15731389

A novel "modularized" optical sensor for pH monitoring in biological matrixes.

PubMed

Liu, Xun; Zhang, Shang-Qing; Wei, Xing; Yang, Ting; Chen, Ming-Li; Wang, Jian-Hua

2018-06-30

A novel core-shell structure optical pH sensor is developed with upconversion nanoparticles (UCNPs) serving as the core and silica as the shell, followed by grafting bovineserumalbumin (BSA) as another shell via glutaraldehyde cross-linking. The obtained core-shell-shell structure is shortly termed as UCNPs@SiO 2 @BSA, and its surface provides a platform for loading various pH sensitive dyes, which are alike "modules" to make it feasible for measuring pHs within different pH ranges by simply regulating the type of dyes. Generally, a single pH sensitive dye is adopted to respond within a certain pH range. This study employs bromothymol blue (BTB) and rhodamine B (RhB) to facilitate their responses to pH variations within two ranges, i.e., pH 5.99-8.09 and pH 4.98-6.40, respectively, with detection by ratio-fluorescence protocol. The core-shell-shell structure offers superior sensitivity, which is tens of times more sensitive than those achieved by ratio-fluorescence approaches based on various nanostructures, and favorable stability is achieved in high ionic strength medium. In addition, this sensor exhibits superior photostability under continuous excitation at 980 nm. Thanks to the near infrared excitation in the core-shell-shell structure, it effectively avoids the self-fluorescence from biological samples and thus facilitates accurate sensing of pH in various biological sample matrixes. Copyright © 2018 Elsevier B.V. All rights reserved.

Rational design of a tripartite-layered TiO2 photoelectrode: a candidate for enhanced power conversion efficiency in dye sensitized solar cells.

PubMed

Khan, Javid; Gu, Jiuwang; He, Shiman; Li, Xiaohui; Ahmed, Gulzar; Liu, Zhongwu; Akhtar, Muhammad Nadeem; Mai, Wenjie; Wu, Mingmei

2017-07-20

A tri-layered photoelectrode for dye-sensitized solar cells (DSSCs) is assembled using single crystal hollow TiO 2 nanoparticles (HTNPs), sub-micro hollow TiO 2 mesospheres (SHTMSs) and hierarchical TiO 2 microspheres (HTMSs). The bottom layer composed of single crystal hollow TiO 2 nanoparticles serves to absorb dye molecules, harvest light due to its hollow structure and keep a better mechanical contact with FTO conducting glass; the middle layer consisting of sub-micro hollow mesospheres works as a multifunctional layer due to its high dye adsorption ability, strong light trapping and scattering ability and slow recombination rates; and the top layer consisting of hierarchical microspheres enhances light scattering. The DSSCs made of photoanodes with a tripartite-layer structure (Film 4) show a superior photoconversion efficiency (PCE) of 9.24%, which is 7.4% higher than a single layered photoanode composed of HTNPs (Film 1: 8.90%), 4.6% higher than a double layer-based electrode consisting of HTNPs and SHTMSs (Film 2: 9.03%) and 2.6% higher than a double layer-based electrode made of HTNPs and HTMSs (Film 3: 9.11%). The significant improvements in the PCE for tri-layered TiO 2 photoanodes are mainly because of the combined effects of their higher light scattering ability, long electron lifetime, fast electron transport rate, efficient charge collection and a considerable surface area with high dye-loading capability. This study confirms that the facile tri-layered photoanode is an interesting structure for high-efficiency DSSCs.

Fast calcium and voltage-sensitive dye imaging in enteric neurones reveal calcium peaks associated with single action potential discharge.

PubMed

Michel, K; Michaelis, M; Mazzuoli, G; Mueller, K; Vanden Berghe, P; Schemann, M

2011-12-15

Slow changes in [Ca(2+)](i) reflect increased neuronal activity. Our study demonstrates that single-trial fast [Ca(2+)](i) imaging (≥200 Hz sampling rate) revealed peaks each of which are associated with single spike discharge recorded by consecutive voltage-sensitive dye (VSD) imaging in enteric neurones and nerve fibres. Fast [Ca(2+)](i) imaging also revealed subthreshold fast excitatory postsynaptic potentials. Nicotine-evoked [Ca(2+)](i) peaks were reduced by -conotoxin and blocked by ruthenium red or tetrodotoxin. Fast [Ca(2+)](i) imaging can be used to directly record single action potentials in enteric neurones. [Ca(2+)](i) peaks required opening of voltage-gated sodium and calcium channels as well as Ca(2+) release from intracellular stores.

Metal-free organic sensitizers for use in water-splitting dye-sensitized photoelectrochemical cells

PubMed Central

Swierk, John R.; Méndez-Hernández, Dalvin D.; McCool, Nicholas S.; Liddell, Paul; Terazono, Yuichi; Pahk, Ian; Tomlin, John J.; Oster, Nolan V.; Moore, Thomas A.; Moore, Ana L.; Gust, Devens; Mallouk, Thomas E.

2015-01-01

Solar fuel generation requires the efficient capture and conversion of visible light. In both natural and artificial systems, molecular sensitizers can be tuned to capture, convert, and transfer visible light energy. We demonstrate that a series of metal-free porphyrins can drive photoelectrochemical water splitting under broadband and red light (λ > 590 nm) illumination in a dye-sensitized TiO2 solar cell. We report the synthesis, spectral, and electrochemical properties of the sensitizers. Despite slow recombination of photoinjected electrons with oxidized porphyrins, photocurrents are low because of low injection yields and slow electron self-exchange between oxidized porphyrins. The free-base porphyrins are stable under conditions of water photoelectrolysis and in some cases photovoltages in excess of 1 V are observed. PMID:25583488

A Simple Experiment for Visualizing Diffusion

ERIC Educational Resources Information Center

Helseth, L. E.

2011-01-01

We propose a simple and fascinating experiment for studying diffusion in gels using a pH-sensitive dye. By doping agar with methyl red, we obtain a gel which rapidly reacts to changes in pH by changing its absorption spectrum. The pH gradients can be followed using a digital camera, and we demonstrate here that the pH-sensitive colour changes can…

Fluorescence lifetime imaging with near-infrared dyes

NASA Astrophysics Data System (ADS)

Becker, Wolfgang; Shcheslavskiy, Vladislav

2013-02-01

Near-infrared (NIR) dyes are used as fluorescence markers in small-animal imaging and in diffuse optical tomography of the human brain. In these applications it is important to know whether the dyes bind to proteins or other tissue constituents, and whether their fluorescence lifetimes depend on the targets they are bound to. Unfortunately, neither the lasers nor the detectors of commonly used confocal and multiphoton laser scanning microscopes allow for excitation and detection of NIR fluorescence. We therefore upgraded existing confocal TCSPC FLIM systems with NIR lasers and NIR sensitive detectors. In multiphoton systems we used the Ti:Sa laser as a one-photon excitation source in combination with an NIR-sensitive detector in the confocal beam path. We tested a number of NIR dyes in biological tissue. Some of them showed clear lifetime changes depending on the tissue structures they are bound to. We therefore believe that NIR FLIM can deliver supplementary information on the tissue constitution and on local biochemical parameters.

Indoor Light Performance of Coil Type Cylindrical Dye Sensitized Solar Cells.

PubMed

Kapil, Gaurav; Ogomi, Yuhei; Pandey, Shyam S; Ma, Tingli; Hayase, Shuzi

2016-04-01

A very good performance under low/diffused light intensities is one of the application areas in which dye-sensitized solar cells (DSSCs) can be utilized effectively compared to their inorganic silicon solar cell counterparts. In this article, we have investigated the 1 SUN and low intensity fluorescent light performance of Titanium (Ti)-coil based cylindrical DSSC (C-DSSC) using ruthenium based N719 dye and organic dyes such as D205 and Y123. Electrochemical impedance spectroscopic results were analyzed for variable solar cell performances. Reflecting mirror with parabolic geometry as concentrator was also utilized to tap diffused light for indoor applications. Fluorescent light at relatively lower illumination intensities (0.2 mW/cm2 to 0.5 mW/cm2) were used for the investigation of TCO-less C-DSSC performance with and without reflector geometry. Furthermore, the DSSC performances were analyzed and compared with the commercially available amorphous silicon based solar cell for indoor applications.

An integrated optical oxygen sensor fabricated using rapid-prototyping techniques.

PubMed

Chang-Yen, David A; Gale, Bruce K

2003-11-01

This paper details the design and fabrication of an integrated optical biochemical sensor using a select oxygen-sensitive fluorescent dye, tris(2,2'-bipyridyl) dichlororuthenium(ii) hexahydrate, combined with polymeric waveguides that are fabricated on a glass substrate. The sensor uses evanescent interaction of light confined within the waveguide with the dye that is immobilized on an SU-8 waveguide surface. Adhesion of the dye to the integrated waveguide surface is accomplished using a unique process of spin-coating/electrostatic layer-by-layer formation. The SU-8 waveguide was chemically modified to allow the deposition process. Exposure of the dye molecules to the analyte and subsequent chemical interaction is achieved by directly coupling the fluid channel to the integrated waveguide. The completed sensor was linear in the dissolved oxygen across a wide range of interest and had a sensitivity of 0.6 ppm. A unique fabrication aspect of this sensor is the inherent simplicity of the design, and the resulting rapidity of fabrication, while maintaining a high degree of functionality and flexibility.