Application In Dye-sensitized Solar Cells Research Articles

Hybrid carboxymethyl kappa-carrageenan/carboxymethyl cellulose- based biopolymer electrolytes for dye-sensitized solar cell application

Hybrid carboxymethyl kappa-carrageenan/carboxymethyl cellulose- based biopolymer electrolytes for dye-sensitized solar cell application

Fabrication electrospun GO/CS/PVA nanofibers and their application in dye-sensitized solar cells

In this study, graphene oxide (GO) was prepared by the Hummers method. GO/CS/PVA fibers were prepared by an electrospinning method. The structure, morphology and size of the electrospun materials were characterized by X – ray diffraction (XRD) and a scanning electron microscope (SEM). Fourier transformation infrared (FTIR) was used to confirm the formation of PVA/CS/GO. Raman spectroscopy was used to analyze the characteristic functional groups of carbon materials in GO. GO/CS/PVA nanofibers were successfully synthesized with an average diameter of about 108 nm and the bandgap energy was 3.2 eV. The nanofibers were used as a counter electrode for dye-sensitized solar cells. With the natural dye extracted from magenta leaves and the counter electrode based on GO/CS/PVA, the solar energy-to-electrical energy conversion efficiency was 0.65%.

Dye-Sensitized Solar Cell (DSSC) Applications based on Cyano Functional Small Molecules Dyes

This work focused on synthesizing of the electro active two small molecules ((2E)-2-Cyano-3-[4'-(2,5-di-2 thienyl-1H-pyrrol-1-yl) biphenyl-4-yl] acrylic acid (MC-20) (2E) -2-Cyano-3-5-[4-(2,5-di-2-thienyl-1H pyrrol-1 yl) phenyl] -2-thienyl acrylic acid (MC-28)) consisting of planar molecule part with different absorptions-emissions energy levels and applications of these small molecules in DSSC device to understand their performance. The optical properties of MC-20

Improved luminescence performance of Yb3+-Er3+-Zn2+: Y2O3 phosphor and its application to solar cells

Upconversion materials (UC) can convert low-energy photons into visible light and, therefore, can be incorporated in solar cells to increase the absorption of visible light. This study synthesized UC nanophosphors Yb3+, Er3+: Y2O3 and Yb3+, Er3+, Zn2+: Y2O3 by a simple co-precipitation method for application in dye-sensitized solar cells (DSSCs). The impact of the enhancement in the concentration of Zn2+ on the photoluminescence (PL) and color point of the synthesized nanophosphors was also investigated. The synthesized nanophosphors emitted intense red and weaker green emissions upon excitation at 980 nm. The incorporation of Zn2+ to the Yb3+, Er3+: Y2O3 nanophosphors leads to color tunability in the red and yellow regions. Furthermore, the synthesized nanophosphors were incorporated into the DSSC photoanode to form a TiO2-UC-based DSSC for converting near-infrared (NIR) into visible light. We observed that the TiO2-UC-based DSSC showed an enhancement ratio in current density and power conversion efficiency of 17.4% and 16.6%, respectively, compared to the bare TiO2-based DSSC. These results reveal that UC-based Yb3+, Er3+, Zn2+: Y2O3 nanophosphors are useful in improving the efficiency of DSSCs and in color tunability applications.

Zinc phthalocyanine absorbance in the near-infrared with application for transparent and colorless dye-sensitized solar cells

Transparent and colorless solar cells are attractive new photovoltaic devices as they could bring new opportunities to harness sunlight energy and particularly for their integrations in windows. In this work, a new zinc phthalocyanine was synthesized and investigated as sensitizer in dye sensitized solar cell (DSSC) for this purpose. The zinc phthalocyanine features a benzoic acid anchoring group and six thio(4-tertbutylphenyl) substituents in position alpha of the phtalocyanine. The dye was characterized by absorption and emission spectroscopy and by electrochemistry. The physico-chemical properties show that the dye fulfills the criteria for such an application. A detailed computational study indicates that the electronic communication with TiO2 conduction is weak owing to the absence of overlapping of the wavefunctions of the dye with those of the TiO2 semiconductor. The photovoltaic performances of the zinc phthalocyanine were measured in TiO2 based DSSC and revealed inefficient electron injection and certainly explained by the weak electronic coupling of the 2 dye with TiO2 that limits electron injection efficiency. Strategy is proposed to make better performing sensitizers.

Role of tannic acid in desiging of electrically active and magnetic gold nanoparticles and enhanced photovoltaic performance of gold@titania photoanode in DSSC

We describe here in significance of tannic acid in obtaining size dependent electrochemically active and magnetic gold nanoparticles (GNPs). In this account, two types of GNPs (SCGNPs and SC-TAGNPs) were synthesized by using sodium citrate and sodium citrate-tannic acid as reducing agents, respectively. Highly monodispersed, uniformly distributed and small size GNPs were produced when tannic acid was used together with sodium citrate. SC-TAGNPs exhibited room temperature ferromagnetism while SCGNPs revealed diamagnetism. With higher anodic peak current and lower charge transfer resistance, the SC-TAGNPs exhibited better conductivity and electron transfer ability than SCGNPs. Mott-Schottky analysis revealed n-type semiconducting behavior of GC/SCGNPs & GC/SC-TAGNPs and showed positive shift in flat-band potential of GC/SC-TAGNPs compared to GC/SCGNPs suggesting better conductivity of SC-TAGNPs. Subsequently, SCGNPs and SC-TAGNPs were added to TiO2 nanoparticles to fabricate modified titania photoanodes (SCGNPs@TiO2 and SC-TAGNPs@TiO2) for dye-sensitized solar cells (DSSCs) application. With the use of TiO2, SCGNPs@TiO2 and SC-TAGNPs@TiO2 photoanodes, the short-circuit current density (JSC) was observed to be 2.18, 4.50 and 6.68 mA/cm2, while energy conversion efficiency (η) was found to be 0.75, 1.74 and 2.50%, respectively. The TiO2 photoanode employing SC-TAGNPs exhibited remarkably increased JSC and η by ∼48 and ∼44%, respectively, then SCGNPs modified photoanode.

Synthesis and characterisation of Cu - Doped TiO2 nanoparticles for DSSC and photocatalytic applications

In the present work, copper-doped TiO2 nanoparticles were synthesized via sol-gel technique with different molar concentration of copper precursor (0.025 M-CT-1, 0.05 M-CT-2, 0.1 M-CT-3 and 0.2 M-CT-4). The effect of copper doping on the structural, morphological, compositional, optical and electrical properties of TiO2 was systematically analyzed for its better suitability as photoanode in Dye-Sensitized Solar Cells (DSSC) and photocatalyst in dye degradation. From structural analysis, all the synthesized samples show anatase phase with a tetragonal crystal system. The broadening and shift in the peaks of the synthesized samples show the successful incorporation of Cu ions into TiO2 lattices. All the synthesized samples exhibit spherical shape morphology with slight agglomeration. EDS analysis exhibit the purity of the synthesized nanoparticles with the presence of only Ti, O, and Cu. UV-DRS analysis reveals the decrease in reflectance of the TiO2 with increasing the Cu concentration. The bandgap values of the Cu–TiO2 decreased from 2.66 to 2.40 eV with the increase of copper concentration. From PL analysis, the peak observed at 380.20, 469.56 and 535.24 nm corresponds to the band-band PL emission, free excitons, and oxygen vacancies, respectively. Further, we have fabricated DSSC using Cu-doped TiO2 as a photoanode without treatment of any scattering layer and we have obtained the maximum efficiency of 3.90% for 0.1 M Cu–TiO2 (CT-3). Similarly, the maximum degradation efficiency of 97.12% was obtained against rhodamine-B dye with the highest regression coefficient (R2 = 0.9957) and lesser half-life degradation time (t1/2 = 47.1428 min) for CT-3. This higher efficiency was not reported elsewhere using Cu-dopant concentrations. From these observations, it was concluded that 0.1 M concentration of Cu was the optimum dopant concentration with TiO2 which was suitable for DSSC and photocatalytic applications.

Development of quasi solid state dye sensitized solar cells

Dye Sensitized Solar Cells (DSSCs) present a significant renewable energy source in terms of control of different parameters governing flexibility, efficiency, lifetime and cost. The liquid electrolytes used inside the cells are generally responsible for the leakage and inefficient encapsulation related issues. These are critical for practical applications of DSSCs. The choice of electrolyte medium used in the cell should take into account the fast regeneration of electrolyte and redox potential of the dye. Organic dyes in general, exhibit better extinction coefficients and variant color ranges. The present work is focused on quasi solid state DSSCs based on an organic dye. For the fabrication of devices, nanocrystalline titanium-di-oxide (TiO2) films were used as the photoanode and well known organic dye Eosin B as the sensitizer. The photovoltaic performance of the cells was measured at different light intensities. The results exhibited the quantum efficiency of organic dye Eosin B which can be used as a potential sensitizer in conjugation with quasi solid state electrolytes. Copyright © 2017 VBRI Press.

Synthesis and Computational Characterization of Organic UV-Dyes for Cosensitization of Transparent Dye-Sensitized Solar Cells.

The fabrication of colorless and see-through dye-sensitized solar cells (DSCs) requires the photosensitizers to have little or no absorption in the visible light region of the solar spectrum. However, a trade-off between transparency and power conversion efficiency (PCE) has to be tackled, since most transparent DSCs are showing low PCE when compared to colorful and opaque DSCs. One strategy to increase PCE is applying two cosensitizers with selective conversion of the UV and NIR radiation, therefore, the non-visible part only is absorbed. In this study, we report synthesis of novel five UV-selective absorbers, based on diimide and Schiff bases incorporating carboxyl and pyridyl anchoring groups. A systematic computational investigation using density functional theory (DFT) and time-dependent DFT approaches was employed to evaluate their prospect of application in transparent DSCs. Experimental UV/Vis absorption spectra showed that all dyes exhibit an absorption band covering the mid/near-UV region of solar spectrum, with a bathochromic shift and a hyperchromic shifts for Py-1 dye. Computational results showed that the studied dyes satisfied the basic photophysical and energetics requirements of operating DSC as well as the stability and thermodynamical spontaneity of adsorption onto surface of TiO2. However, results revealed outperformance of the thienothiophene core-containing Py-1 UV-dye, owing to its advantageous structural attributes, improved conjugation, intense emission, large Stokes shift and maximum charge transferred to the anchor. Chemical compatibility of Py-1 dye was then theoretically investigated as a potential cosensitizer of a reference VG20-C2 NIR-dye. By the judicious selection of pyridyl anchor-based UV-absorber (Py-1) and carboxyl anchor-based NIR-absorber (VG20), the advantage of the optical complementarity and selectivity of different TiO2-adsorption-site (Lewis- and Bronsted-acidic) can be achieved. An improved overall PCE is estimated accordingly.

Fabrication of electrospun BaTiO3/chitosan/PVA nanofibers and application for dye-sensitized solar cells

Perovskite BaTiO3 nanoparticles were synthesized by a hydrothermal method. BaTiO3/chitosan (CS)/Polyvinyl alcohol (PVA) nanofibers with an average diameter of 265.3 ± 52 nm were fabricated via an electrospinning method. The nanofibers were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), and thermal analysis method (TGA). The photoanodes of dye-sensitized solar cells (DSSC) were fabricated based on the BaTiO3/CS/PVA nanofibers. The photovoltaic properties of the cells were calculated based on the current density – voltage curves. The maximum power conversion efficiency of DSSC with CS/PVA/BaTiO3 nanofibers was 0.49% with the natural dye sensitizer extracted from the leaf of the magenta plant.

Evaluation of performance characteristics of nano TiO2 and TiO2-ZnO composite for DSSC applications and electrochemical determination of potassium ferrocyanide using cyclic voltammetry

Nanoparticles of TiO2 and TiO2-ZnO composite (2:1 molar ratio) were synthesized utilizing the sol-gel and solution combustion approaches, respectively. Scanning electron microscopic, energy dispersive x-ray, x-ray diffraction, UV-visible spectroscopy, and Brunauer–Emmett–Teller analysis were employed to characterize the synthesized nanoporous TiO2 and the composite of TiO2-ZnO nanoparticles. Fabrication of dye-sensitized solar cells (DSSCs) was carried out by incorporating the synthesized nanoporous materials coating on the photoanodes using the doctor blade technique. Nano TiO2 and the composite of TiO2-ZnO were also analyzed using cyclic voltammetry test, and their performance was compared for the electrochemical detection of potassium ferrocyanide. The composite of TiO2-ZnO exhibited better electrocatalytic activity in comparison with the pure TiO2 nanoparticles. The fabricated DSSCs by employing nano TiO2 particles and TiO2-ZnO composite as the semiconductor photoanode materials were compared for photovoltaic performance. The DSSC fabricated with TiO2 nanoparticles exhibited better photovoltaic performance with an efficiency of 2.22% and a current density of 4.152 mA cm−2 than that fabricated with TiO2-ZnO composite with an efficiency of 0.0022% and a short circuit current density of 0.014 mA cm−2.

Effects of different iodide salts on the electrical and electrochemical properties of hybrid biopolymer electrolytes for dye-sensitized solar cells application

Effects of different iodide salts on the electrical and electrochemical properties of hybrid biopolymer electrolytes for dye-sensitized solar cells application

Surface properties of chlorophyll-a sensitized TiO2 nanorods for dye-sensitized solar cells applications

Dye-sensitized solar cells (DSSCs) based on TiO2 nanorods have recently achieved improvement by tuning surface polarity with the help of chlorophyll-a dye. Additionally, we have successfully explored the effects of surface free energy, oxygen defect concentration, micro strain, surface morphology, chemical composition, photoluminescence, and surface properties of chlorophyll-a sensitized TiO2 nanorods. Sensitization on TiO2 nanorods has been tested with photoelectrochemical performance, and the resulting surface shows a superhydrophobicity with CA = 154 ± 30 while oxygen defect is reduced to 2.7228 × 1021 cm−3. The surface free energy has been successfully studied with the help of Owens-Wendt-Rabel-Kaelble (OWRK) and the wetting envelope model. A sensitized system of chlorophyll-a and TiO2 nanorods for the DSSC application presents a maximum of 3.69 times PEC improvement under 1000 W light illumination.

Enhanced performance of dye-sensitized solar cells by co-sensitization of metal-complex and organic dye

We systematically investigated a co-sensitized dye comprising of the Ru-complex (N719) dye blended with organic (Coomassie brilliant-blue R-250) as a novel photosensitizer for application in dye-sensitized solar cells (DSSCs). Compared with DSSCs made with the individual dyes, the power conversion efficiency of DSSC with co-sensitized dye is increased by 22 %, i.e., from 9.07 to 11 %. This enhancement results mainly from the significant increase in the open-circuit voltage (VOC) upon co-sensitization due to the upward movement of the conduction band edge and reduction in the charge recombination. Impedance spectroscopy analysis reveals higher charge recombination resistance and greater carrier lifetime for the co-sensitized dye-based DSSC, suggesting that the suppressed recombination due to improved morphology and reduced defects yields a high VOC. Moreover, co-sensitized DSSC exhibited enhanced short circuit current (JSC) and fill factor (FF). This strategy of using a co-sensitized dye as a photosensitizer in DSSCs could pave an effective way to approach high-performance, cost-effective DSSCs.

Photoinduced electrochemical effect of porous BiPOM on TiO2 photoanode performance for dye-sensitized solar cells application

In this study, highly porous bismuth phosphotungstate (BiPOM) was prepared and incorporated onto TiO2 via the hydrothermal method and evaluated towards its effect on photoelectrochemical properties of TiO2 photoanode for use in dye sensitized solar cells (DSSCs). The pristine and nanocomposite materials were characterized by XRD, FTIR, Raman, BET, TGA, FESEM, TEM, UVvis DRS, PL and XPS to elucidate their surface, structural and optical properties. The nanocomposites were then deposited onto FTO electrode and their electrochemical properties were studied using EIS, LSV, and transient photocurrent. Raman results showed a significant Raman blue shift of the Eg, A1 g, and B1 g peaks upon addition of BiPOM on TiO2 materials, indicating a strong electrostatic interaction between TiO2 and BiPOM materials. The FESEM and TEM images confirmed the presence of porous structures that promote good electron diffusion in DSSCs thus, improving the photo conversion efficiency. The TiO2-BiPOM (6%) nanocomposite exhibited reduced energy band gap (2.26 eV) and enhanced electron recombination characteristics as confirmed by UV-Vis and PL techniques respectively. Additionally, upon photoelectrochemical evaluation, TiO2-BiPOM (6%) nanocomposite exhibited excellent charge transfer resistance, highest current response and lowest recombination rate than its counterparts. Therefore, the TiO2-BiPOM (6%) material was recognized as an ideal material for the fabrication of TiO2 based photoanodes due to improved surface morphological properties and electron mobility capacities thus can be extensively investigated for other applications.

Simple phenylene-bridged D-π-A type photosensitizers for DSSC application: Synthesis, optical, electrochemical and theoretical studies

Herein, we report the design and synthesis of two new phenylene-bridged D-π-A configured organic molecules N1-2 carrying two different anchors and the same donor unit, as potential sensitizers for DSSC application. In the new design, a simple O-alkyl substituted phenyl group acts as a donor scaffold, cyanovinylene, and phenylene systems serve as π-spacers, while cyanoacetic acid and barbituric acid units function as electron acceptor/anchoring moieties. The current work also highlights their structural, photophysical, electrochemical, and theoretical investigations, including evaluation of their structure-property relationships. The optical results revealed that chromophores N1-2 display λabs and λemi in the range of 400-420 nm and 550-570 nm, respectively, with a bandgap in the order, 2.51-2.59 eV. Their quantum chemical simulations have provided an insight into the predictions of their structural, molecular, electronic, and optical parameters. Further, the results showcased that the dyes possess all the pre-requisites to act as sensitizers in dye-sensitized solar cells (DSSCs). Conclusively, the study furnishes a deeper understanding of the intricacies involved in the structural modification of phenylene-based dyes for achieving better performance in DSSCs.

Computational investigations on efficient metal-free organic D-π-A dyes with different spacers for powerful DSSCs applications

ABSTRACT Based on 3-(4-((4-carbazol-9-yl-phenyl)ethynyl)phenyl)-2-cyanoacrylic acid (CB1) dye, the six newly planned organic spacer (CBS1-CBS6) dyes were investigated for dye-sensitised solar cell (DSSC) application. The designed dyes have an electron-donor (D) in carbazole through a different π-spacer and an electron-acceptor (A) in 2-cyanoacrylic acid. The density functional theory (DFT) and the time-dependent DFT (TD-DFT) evaluated the DSSCs of the molecules in the strategic platform. The results display that the TD-DFT method, using different functionals with exchange (XC) and long-range correlated (LC), was discussed. The electronic and optical properties of the CBS1-CBS6 dyes were discussed. The highest occupied molecular orbitals (HOMOs) and lowest unoccupied MOs (LUMOs) of the CBS1-CBS6 molecules can confirm the probable response to the regeneration and electron injection process. Also, the calculated results, such as injection driving force , light-harvesting efficiencies (LHE), regeneration and open-circuit photovoltage of the CBS1-CBS6 sensitisers, were presented. A good contract of theoretical calculations with the literature data reveals a better understanding of the spacer's PV performance. To conclude, benzo[c][1,2,5]oxadiazole (CBS2) and [1,2,5]oxadiazolo[3,4-c]pyridine (CBS5) spacers were the best candidates for DSSCs, because of their smaller energy gap and red-shifted absorption wavelengths.

Different metal upper porphyrin based self-assembly sensitizers for application in efficient dye-sensitized solar cells

Four different metal atom dyes MP (M: Zn, Cd, Ag, Cu) as upper porphyrin molecular have been designed and synthesized. On the other side of ZnPA contains four carboxylic acids as the horizontal anchor porphyrin for binding to TiO2. We constructed MP-ZnPA assembled approach, and applied in dye-sensitized solar cells. Photoelectrochemical studies reveal the self-assembled structure dye photocurrent (Jsc) are higher than anchor porphyrin. The enhancement of Jsc can be ascribed to the improved light-harvesting ability induced by the axially coordinated MP. However, upper different metal atom porphyrins cannot play a positive role in improving the photovoltages (Voc) because of MP-ZnPA devices possess the dye aggregation. The effects of the MP-ZnPA assembled on the optical, theory calculations and photovoltaic properties were investigated. AgP-ZnPA and ZnP-ZnPA have the higher molar extinction coefficient and sufficient charge injection into the TiO2 conduction band. Therefore, AgP-ZnPA and ZnP-ZnPA have superior photovoltaic behavior. We constructed a three-layer self-assembled (ZnP1-AgP-ZnPA) solar cell, which the photovoltaic efficiency of the three-layer self-assembled solar cell is significantly reduced. Consequently, double-layer self-assembly, which is one of the effective strategies for improving the performance of self-assembly supramolecular solar cells.

DFT and TD-DFT studies for optoelectronic properties of coumarin based donor-π-acceptor (D-π-A) dyes: applications in dye-sensitized solar cells (DSSCS)

A series of six coumarin based dye derivatives were investigated and their geometry and optoelectronic properties elucidated for suitability in dye-sensitized solar cells (DSSCs) using TD-DFT/B3LYP with 6-31G basis set. D-π-A schemes were developed by attaching various donors and acceptors to coumarin dye (CM) to calculate changes in their photovoltaic properties. D2-CM-A2 and D4-CM-A4 showed less dihedral angle because of the low steric effect between donor and connector. The D1-CM-A1 and D2-CM-A2 results of intramolecular charge transfer were higher because of low bond length and a strong group of electron donors. The results revealed that LUMO energies of D1-CM-A1, D2-CM-A2, D3-CM-A3 and D4-CM-A4 were higher than the conduction band edge of TiO2 electrode (−4.0 eV) suggesting that these dyes will inject the electrons into the conduction band of the semiconductor. In addition, the light harvest efficiency (LHE), open-circuit voltage (VOC) and band energy gap (Eg) values are calculated in the gas phase, as well as in the solvent phase. This study shows that D1-CM-D1 and D2-CM-A2 derivatives have better properties for application in the DSSCs.

Novel Down-converting single-phased white light Pr3+ doped BaWO4 Nanophosphors material for DSSC applications

White Nanophosphors based on praseodymium doped barium tungstate matrix (y mol Pr3+: BaWO4 (PBWO) (y = 0.01, 0.03, 0.05, 0.07 mol) were synthesized by ultrasound assisted hydrothermal method in the presence of citric acid and characterized as novel down-conversion materials for dye-sensitized solar cells (DSSCs) applications. The different prepared PBWO Nanophosphors show high crystalline tetragonal phase with nano-cubic morphology. The PBWO photoluminescence spectra give strong emission peaks at 486, 529, 615, 623 and 643 nm are corresponding to the 3P0→3H4, 3P1→3H5, 1D2→3H4, 3P0→3H6 and 3P0→3F2 transitions of Pr3+, respectively. These photoluminescence spectra are assigned to blue, green and red-light regions which cover the whole visible light region. It means that these Nanophosphor materials are promising materials for down-conversion applications. By varying the Pr3+ ion conc., it was found that the optimum conc. of Pr3+ ion was 0.05 mol which gives the highest photoluminescence intensity. The prepared Nanophosphors were applied in DSSCs as a top down-converting layer on the photoactive TiO2 electrode. A high conversion efficiency (η) of 8.08% was achieved by the application of top (PBWO: 0.05 mol Pr3+) down-converting material compared with a 4.17% efficiency of the non-modified DSSC. This enhancement is probably due to the improved UV radiation harvesting via a down-conversion luminescence process.