Sensitizers For Dye-sensitized Solar Cells Research Articles

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.

Synthesis of benzimidazole moiety heteroleptic ruthenium complex and use as sensitizer in dye-sensitized solar cells

Synthesis of benzimidazole moiety heteroleptic ruthenium complex and use as sensitizer in dye-sensitized solar cells

A novel idea of using dyes extracted from the leaves of Prosopis juliflora in dye – Sensitized solar cells

As a step of environmental protection by waste management, fresh and dried leaves of Prosopis juliflora were utilised in preparing natural dyes with ethanol and acetone as solvents and were made use as sensitizers in Dye-Sensitized Solar Cells (DSSC). Four dyes were taken in total, UV–Vis and FTIR spectroscopic studies were performed for the prepared dye sensitizers. J-V Characterization study was carried out for the fabricated cells and important parameters like Short-circuit current (J sc ), open-circuit voltage (V oc ), fill-factor (FF) and photo-conversion efficiency were determined. It was seen that the cell with dye extracted from dried leaves using acetone as solvent showed the highest photo-conversion efficiency of 0.322 % among the four cells fabricated. While the cells prepared with the fresh leaves showed an efficiency of 0.017 % and 0.225 % with ethanol and acetone respectively and the cell with the dye taken from the dried leaves using ethanol solvent exhibited an efficiency of 0.058 %. • DSSCs made-up with one of the most dangerous invasive species - Prosopis juliflora . • Ethanol & acetone were used in obtaining dyes from fresh & dried leaves of Prosopis . • Prosopis is being reported for the first time in DSSC with 0.3 % efficiency. • Recorded higher efficiency than many DSSCs made with dyes extracted from leaves. • Effect of this invasive tree in many countries can be reduced by using them in DSSC.

Enhancing the Photoelectric Properties of Zinc Porphyrin Dyes by Introducing Five-Membered Heterocyclic Rings into the Electron Donor: A Density Functional Theory and Time-Dependent Density Functional Theory Study.

To fabricate highly efficient dye sensitizers for dye-sensitized solar cells, new zinc porphyrin dye sensitizers were designed based on one of the most efficient dyes, YD2-o-C8, by introducing electron-rich heterocyclic rings into the electron donor. Five potentially efficient dyes, Dye1–5, were obtained by replacing the phenyl group of the donor in YD2-o-C8 with pyrrolyl, furyl, and thienyl groups. The electronic structures, absorption spectra, intramolecular charge-transfer characteristics, and excited-state lifetimes of the designed dyes were investigated using the density functional theory and time-dependent density functional theory methods. All the designed dyes exhibit better photoelectric properties than those of YD2-o-C8. Compared with YD2-o-C8, the designed new dyes have smaller frontier molecular orbital energy gaps and obvious red-shifting absorption spectra in the Q band. The analyses of charge density difference plots and intramolecular charge-transfer characteristics indicated that the designed dyes can better promote intramolecular charge transfer and electron–hole separation. Among the five designed dyes, Dye1 with a pyrrolyl group exhibits the best performance. Dye3 and Dye5 with methyl-furyl and methyl-thienyl groups, respectively, exhibit the next best performance. Dye2 and Dye4 with furyl and thienyl groups, respectively, are the worst performers. The introduced methyl group can further improve the electron-donating ability of heterocyclic rings and promote the red shift of the Q bands and intramolecular charge transfer of dyes. The excited-state lifetimes of the new dyes were in the following order: YD2-o-C8 < Dye4 < Dye2 < Dye5 < Dye3 < Dye1, which shows their stronger abilities to inject electrons into semiconductor films.

Non-aggregating zinc phthalocyanine sensitizer with bulky diphenylphenoxy donor groups and pyrazole-3-carboxylic acid anchoring group for coadsorbent-free dye-sensitized solar cells

A novel unsymmetrical zinc phthalocyanine complex (PCA-ZnPc-3) containing six 2,6-diphenylphenoxy donor groups and pyrazole-3-carboxylic acid anchoring group has been synthesized and used as a sensitizer for dye-sensitized solar cells (DSSCs). The optical, electrochemical and photovoltaic characteristics were evaluated and compared with the dyes containing the same anchoring group and tert-butyl (PCA-ZnPc-1) or hexylsulfanyl (PCA-ZnPc-2) donor groups, developed by our group. The DSSC with PCA-ZnPc-3 exhibited a higher power conversion efficiency (PCE) of 2.04% as compared to that of PCA-ZnPc-1 (PCE = 1.74%) and PCA-ZnPc-2 (PCE = 1.89%). This enhancement in efficiency may be ascribed to the less dye aggregation and appropriate dye coverage. These results suggest that the incorporation of 2,6-diphenylphenoxy into pyrazole-3-carboxylic acid-based zinc phthalocyanine sensitizers can improve photovoltaic performance of DSSCs.

Performance of Natural Dye Extracted from Annatto, Black Plum, Turmeric, Red Spinach, and Cactus as Photosensitizers in TiO2NP/TiNT Composites for Solar Cell Applications

This paper is aimed at how to select, extract, and characterize natural dyes and to use them as sensitizers in dye-sensitized solar cells (DSSCs). Dyes obtained from fresh sources of annatto fruits, black plums, cactus fruits, turmeric roots, and red spinach leaves were used as sensitizers. The dye pigments were analyzed using UV-Vis spectrophotometer and FT-IR for the characterization of their spectral properties. The combination from Titanium dioxide paste with the powdered nanotubes was used as photoanodes for DSSCs. The photovoltaic properties of the DSSCs such as efficiency, fill factor, open-circuit voltage, and short circuit current were studied using a standard illumination of air-mass 1.5 global (AM 1.5 G) having an irradiance of 100 mW/cm2. The highest power conversion efficiencies (η) of 0.7% was achieved for the DSSCs fabricated using dye extracted from annatto fruits and 0.4% each for dyes extracted from black plum fruits and cactus fruits, respectively. The widespread accessibility of these fruits, roots, and leaves and ease of extraction of dyes from these ordinarily available natural resources render them unique and low-cost candidates for solar cell fabrication.

A Combined Experimental and Theoretical Investigation of Perylene Based Dyes as Sensitizer for Dye-Sensitized Solar Cell

A Combined Experimental and Theoretical Investigation of Perylene Based Dyes as Sensitizer for Dye-Sensitized Solar Cell

Catalytic Effect of 1,4-Dioxane on the Kinetics of the Oxidation of Iodide by Dicyanobis(bipyridine)iron(III) in Water

Dye-sensitized solar cells (DSSCs) are a technically and financially viable alternative to today’s photovoltaic systems using p-n junctions. The two functions are isolated here, which are unlike traditional systems where the semiconductor is thought to perform both light absorption and charge carrier transport. This article discusses the potential use of dicyanobis(bipyridine)iron(III) to oxidize iodide as a sensitizer in DSSCs. However, it is critical to understand the kinetics of this essential process in order to understand the mechanism of electron transport. The oxidation of iodide by dicyanobis(bipyridine)iron(III) in three reaction media was studied: water, 10% v/v 1,4-dioxane-water, and 20% v/v 1,4-dioxane-water. The reaction was carried out in a regular laboratory setting, with no special sensitive conditions or the use of expensive materials, making it a cost-effective and practical method. Dicyanobis(bipyridine)iron(III) oxidized iodide in selected media at 0.06 M ionic strength and constant temperature. The reaction was subjected to a spectrophotometric analysis. The data were acquired by measuring the rise in visible absorbance as a function of time after the formation of dicyanobis(bipyridine)iron(II). The reaction proceeded with an overall fractional (0.5), first order, and third order in water, 10% media, and 20% media, respectively. The presence of dicyanobis(bipyridine)iron(III) in either of the reaction media had no effect on the rate. The effect of protons (H+) on the rate constant indicated resistance in water and catalysis in dioxane-water media containing 10–20% dioxane. When the ionic strength was raised, there was no change in the rate constant in water, but there was a deceleration in both binary solvent media. In an aqueous medium, the thermodynamic parameters of activation were computed as Ea 46.23 kJ mol−1, 24.62 M s−1, ΔH# 43.76 kJ mol−1, ΔS# −226.5 J mol−1 K−1, and ΔG# 111.26 kJ mol−1 (25 °C). By increasing the rate of the reaction to its maximum, this study discovered the binary solvent media with the highest catalytic efficiency, i.e., 20% v/v 1,4-dioxane-water, which may increase the efficiency of DSSCs without using any expensive material or unusual experimental conditions.

Y-shape structured azo dyes with self-transforming feature to zwitterionic form as sensitizer for DSSC and DFT investigation of their photophysical and charge transfer properties

Two novel azo dyes with D-π-A-π-D structures were designed and synthesized to investigate the relationship between molecular structure and sensitizing performance on applying for dye-sensitized solar cells (DSSCs) in comparison with their linear counterparts. Introducing hydroxyl auxiliary groups and arranging π-conjugation length as two parallel and series structural architectures, Y-shape and linear, led to red shift in absorption wavelength and increase in absorption intensity for the Y-shape pattern providing an efficient charge transfer pathway and improved Jsc and η of the DSSCs. Emerging a zwitterionic form, azonium structure, of the sensitizer in parallel configuration for the dyes 1a.p and 1b.p, enhanced light absorption domain and changed anchoring fashion could engendering improved electronic overlapping. The easily–synthesized dyes were evaluated for photophysical and electrochemical properties and turned out that the parallel-decorated dyes displayed better results than the series types as photosensitizers for DSSCs. ATR and Raman spectra clearly showed the adsorption of these dyes on the TiO2 surface. Operational tests of DSSCs, coated by titled azo dyes, illustrated that decorating π-conjugation pattern as parallel structure as well as accessorizing the donor unit with hydroxyl groups improved the photovoltaic performance. Optimized band gap due to participating the azonium structure and restricted electron recombination as well as rectified dye regeneration were proposed as main elements in enhancing performance parameters. A higher solar conversion efficiency was recorded for DSSCs based on the Y-shape dyes compared to other meta azo dye-based cells that were previously reported. Computational calculations were used to corroborate the opto-electrochemical traits of the dyes with a special concern on the influence of structural pattern on photovoltaic features.

Application of new natural dyes extracted from Nasturtium flowers (Tropaeolum majus) as photosensitizer in dye-sensitized solar cells

This work reported the natural dyes extracted from yellow and orange Nasturtium (Tropaeolum majus) flower petals and then used them as sensitizer in dye-sensitized solar cells (DSSCs) for the first time. The functional groups present in the dyes were identified by FTIR spectroscopy which revealed the characteristic peaks of pigments anthocyanins and carotenoids. The UV–Visible analysis of dye extracts showed absorption in the visible region and the dye loaded TiO2 exhibited broad absorption. The density functional theory (DFT) calculation was performed on Lutein, Cyanidin-3-sophoroside, Delphinidine-3-dihexoside and Pelargonidin-3-sophoroside to find out the HOMO and LUMO levels of each. The DSSCs were constructed using these natural extracts as sensitizer dye and photovoltaic performance such as conversion efficiency (η), short-circuit current density (Jsc), open-circuit voltage (Voc) and fill factor (FF) were investigated. The electrochemical impedance spectroscopy (EIS) studies were performed to analyze the charge transfer characteristics. The light-to-electricity conversion efficiency of 0.28% is achieved with Voc of 0.556 V, Jsc of 0.72 mA/cm2 and FF of 0.70 for natural sensitizer extracted from orange petals of Nasturtium flowers.

(Invited) Beta, Beta-Functionalized Push-Pull Opp-Dibenzoporphyrins As Sensitizers for Dye-Sensitized Solar Cells: The Role of the Phenylethynyl Bridge and the Tertiary Amine Push Group

Significant progress has been made on dye-sensitized solar cells sensitized by push-pull porphyrins in recent years.1-3 An effective way to significantly enhance power conversion efficiencies of porphyrin dyes is through installation of push (electron-donating) and pull (electron-withdrawing) groups at porphyrin meso-positions.4-6 In this presentation, we present a different strategy to install push and pull groups at porphyrin beta-positions. Three series of novel opp-dibenzoporphyrins were prepared using this strategy. Our studies show significant push-pull effects for these porphyrins.7 DFT calculations suggest that the inclusion of ethynylphenyl bridge between the donating group and porphyrin core significantly segregate the frontier orbitals, which is a much-favored feature for sensitizers in DSSC. The electronic and optical properties of these beta-extended porphyrins were measured using UV-Vis spectroscopy, life-time and steady state fluorescence spectroscopy, cyclic voltammetry and transient spectroscopy. Their photovoltaic performances were tested in dye-sensitized solar cells. Reference T. Higashino and H. Imahori, Dalton Trans., 2015, 44, 448-463.M. Urbani, M. Gratzel, M. K. Nazeeruddin and T. Torres, Chem. Rev., 2014, 114, 12330-12396.L. L. Li and E. W. Diau, Chem. Soc. Rev., 2013, 42, 291-304.A. Yella, H.-W. Lee, H. N. Tsao, C. Yi, A. K. Chandiran, M. K. Nazeeruddin, E. W.-G. Diau, C.-Y. Yeh, S. M. Zakeeruddin and M. Grätzel, Science, 2011, 334, 629-634.S. Mathew, A. Yella, P. Gao, R. Humphry-Baker, B. F. Curchod, N. Ashari-Astani, I. Tavernelli, U. Rothlisberger, M. K. Nazeeruddin and M. Gratzel, Nat. Chem., 2014, 6, 242-247.G. Di Carlo, A. O. Biroli, F. Tessore, S. Caramori and M. Pizzotti, Coord. Chem. Rev., 2018, 358, 153-177.Y. Hu, S. Yellappa, M. B. Thomas, R. G. W. Jinadasa, A. Matus, M. Shulman, F. D'Souza and H. Wang, Chem Asian J, 2017, 12, 2749-2762.

Organic sensitizers featuring tetrathienosilole core for efficient and robust dye-sensitized solar cells

Siloles are one of the most promising building blocks for the construction of functional materials that exhibit potential application in organic photovoltaic. In the present work, two novel organic dyes featuring highly conjugated and planar tetrathienosilole (TTS) as π-bridge have been successfully synthesized and employed in dye-sensitized solar cells (DSSCs) for the first time. For comparison, dye W13 with non-rigidified 2,2′-bithieno[3,2-b]thiophene linker was prepared as well. The effects of π-bridge rigidification upon the optoelectronic properties as well as the charge transfer energetic and kinetic features of these dyes have been systematically researched. It was found that a significant enhanced open-circuit voltage had been displayed for TTS-based sensitizers as the rigidification of π-bridge with tetrahedral silicon atom. Moreover, the energy levels alignment of the dyes could be fine-tuned through modulating the electron-donating groups to optimize the dyes regeneration process. Under AM 1.5G irradiation, the devices fabricated by W15 employing [Co(phen)3]2+/3+ electrolyte achieve the highest power conversion efficiency of 8.10%, which is about 19% higher than that of W13, demonstrating the great potential of TTS spacer for constructing highly efficient organic sensitizers for DSSCs.

Dye-sensitized solar cells concocted with dyes extracted from fresh and dried leaves of Henna using different solvents

Fresh and dried leaves of Lawsonia inermis (Henna) were used in extracting dyes with variety of solvents such as ethanol, acetone and distilled water. To our knowledge, acetone has been used for the first time as solvent to extract henna dye. These extracted dyes were used as sensitizers in Dye-Sensitized Solar Cells (DSSCs). A sum of six DSSCs were fabricated. Spectroscopic studies (UV–Visible and FTIR) were recorded for all the six dyes extracted and for the photo-anodes prepared. J–V Characterization study was performed for all the cells and parameters such as Voc, Jsc, Vm, Jm, fill-factor and efficiency were calculated for the prepared cells. To our knowledge, the efficiency of DSSCs with sensitizer extracted from henna leaves with acetone and distilled water as solvent has been reported for the first time. It was seen that amongst all the cells prepared, the one with dye extracted from dried leaves using acetone as solvent showed higher efficiency of 0.351% with fill-factor of 0.3765.

Enhanced photovoltaic performance of dye-sensitized solar cells-based Carica papaya leaf and black cherry fruit co-sensitizers

Natural dye sensitizers are attractive as an alternative to expensive and rare organic sensitizers in dye-sensitized solar cells. The partial absorption of solar spectrum by solar cell-based natural dye negates its usefulness as the power conversion efficiency (PCE) is poor. Co-sensitization of two or more natural dyes with variant absorption spectra could be a feasible solution. Herein, Carica papaya leaf (P) and black cherry (B) fruit dye extracts were prepared and used as co-sensitizers at different volume concentration ratios (B:P=1:3, B:P=1:1 and B:P=3:1). The optical performance analysis shows that the light-harvesting ability of the device optimized after the co-sensitization at B:P=3:1 significantly improved. The DSSCs-based B and P show PCEs of 0.25% and 0.29%, respectively. The DSSC-based B:P=3:1 shows the highest PCE of 0.56%. Further investigation using cyclic voltammetry (CV) shows that DSSC-based B:P=3:1 has the smallest electron-injection barrier (ΔEe) among all the fabricated DSSCs while DSSC-based B has the highest ΔEe. Also, electrochemical impedance spectroscopy (EIS) reveals that the DSSC-based B:P=3:1 has the least charge flow resistance, thereby reducing charge recombination in the device. Meanwhile, the radius of the DSSCs-based B arc is the largest depicting presence of high charge flow resistance thereby increasing charge recombination in the device. The co-sensitizer, (B:P=3:1), compensates for absorption defects of single dye ((B or P) and improves the photo-response current. Also, it suppresses the charge recombination in the device and improves the PCE of the device.

Effect of π-Conjugated Spacer in N-Alkylphenoxazine-Based Sensitizers Containing Double Anchors for Dye-Sensitized Solar Cells.

A series of novel double-anchoring dyes for phenoxazine-based organic dyes with two 2-cyanoacetic acid acceptors/anchors, and the inclusion of a 2-ethylhexyl chain at the nitrogen atom of the phenoxazine that is connected with furan, thiophene, and 3-hexylthiophene as a linker, are used as sensitizers for dye-sensitized solar cells. The double-anchoring dye exhibits strong electronic coupling with TiO2, provided that there is an efficient charge injection rate. The result showed that the power conversion efficiency of DP-2 with thiophene linker-based cell reached 3.80% higher than that of DP-1 with furan linker (η = 1.53%) under standard illumination. The photovoltaic properties are further tuned by co-adsorption strategy, which improved power conversion efficiencies slightly. Further molecular theoretical computation and electrochemical impedance spectroscopy analysis of the dyes provide further insight into the molecular geometry and the impact of the different π-conjugated spacers on the photophysical and photovoltaic performance.

Structural Engineering of Organic D-A-π-A Dyes Incorporated with a Dibutyl-Fluorene Moiety for High-Performance Dye-Sensitized Solar Cells.

Structural engineering of the light-harvesting dyes employed in DSSCs (dye-sensitized solar cells) with a systematic choice of the electron-donating and -accepting groups as well as the π-bridge allows the (photo)physical properties of dyes to match the criteria needed for improving the DSSC efficiency. Herein, we report an effective approach of molecular engineering of DSSC sensitizers, aiming to gain insights on the configurational impact of the fluorenyl unit on the optoelectronic properties and photovoltaic performance of DSSCs. Five new organic dyes (GZ116, GZ126, GZ129, MA1116, and MA1118) with a D-A-π-A framework integrated with a fluorenyl moiety were designed and synthesized for DSSCs. The fluorenyl unit is configured as part of the π-spacer for the GZ series, whereas it connected on the electron-deficient quinoxaline motif for the MA series. The devices fabricated from the MA1116 sensitizer produced the best performance under standard AM 1.5 G solar conditions as well as dim-light (300-6000 lx) illumination. The devices fabricated from MA1116 displayed a PCE of 8.68% (Jsc = 15.00 mA cm-2, Voc = 0.82 V, and FF = 0.71) under 1 sun and 26.81% (Jsc = 0.93 mA cm-2, Voc = 0.68 V, and FF = 0.76) under 6000 lx illumination. The device efficiency based on dye MA1116 under 1 sun outperformed that based on the standard N719 dye, whereas a comparable performance between devices based on MA1116 and N719 was achieved under dim-light conditions. A combination of enhancing the charge separation, suppressing dye aggregation, and providing better insulation that prevents the oxidized redox mediator from approaching the TiO2 surface all contribute to the superior performance of DSSCs fabricated based on these light-harvesting dyes. The judicious integration of the fluorenyl unit in a D-A-π-A-based DSSC would be a promising strategy to boost the device performance.

Thiophene-fused carbazole derivative dyes for high-performance dye-sensitized solar cells

Two novel dyes that are similar in chemical structure, except for different donor units, AJ301 and AJ303 were synthesized, characterized and applied as sensitizers in dye-sensitized solar cells (DSSCs). Both dyes exhibited a wide absorption of visible sunlight. The introduction of fused rings on the donor unit of AJ303 presented an appropriate energy level, less recombination and longer electron lifetime to achieve a power conversion efficiency (PCE) of 10.2%, far above that achieved for AJ301 of 6.2% with a [Co(bpy) 3 ] 2+/3+ -based electrolyte under standard AM1.5G solar irradiation (100 mW cm −2 ). The DSSCs based on AJ303 and AJ301 with [Cu(tmby) 2 ] 2+/+ -based electrolyte showed a lower PCE of 8.2% and 5.4%, respectively. Therefore, the results indicated that the introduction of a fused-ring in the donor group is a meaningful synthetic strategy to improve the photovoltaic performance. • Two new metal-free dyes ( AJ301 , AJ303 ) were synthesized. • The thiophene-fused donor has more conducive to obtain higher conversion efficiency. • Both traditional cobalt electrolyte and burgeoning copper electrolyte are used in photovoltaic devices.

Performance Improvements of Bixin and Metal-Bixin Complexes Sensitized Solar Cells by 1-Methyl-3-propylimidazolium Iodide in Electrolyte System

Bixin is one of the potential natural sensitizers used in dye-sensitized solar cells (DSSCs). In this study, bixin was complexed with Cu(II) and Zn(II) to increase its stability. The formation of the complexes was indicated by shifting peaks absorption and the changes in the fine spectral structure observed from the UV-Vis absorption spectra. The metal-bixin complex occurs due to the interaction between the ester groups of bixin and the metal. Bixin, Cu-bixin, and Zn-bixin were used separately as sensitizers in DSSCs. The DSSCs performance was then improved by adding 1-methyl-3-propylimidazolium iodide (MPII) to the electrolyte system. The presence of MPII 0.4 M in KI-I2 electrolyte produced a higher ionic conductivity value (20.44 mS cm–1) than that without MPII (11.14 mS cm–1). This electrolyte system significantly improved DSSCs performance. Under a light intensity of 300 W/m2, the maximum energy conversion efficiencies of DSSC with bixin, Cu-bixin, and Zn-bixin as sensitizers are 0.084, 0.081, and 0.005%, respectively. The Zn-bixin-based DSSC was stable under high light intensity. Under 700 W/m2, its maximum energy conversion efficiency reaches 0.125%. There was a synergistic work observed between the metal-bixin complex and the MPII based electrolyte. This result can open the way for constructing functional materials for solar cell applications.

Band gap energy calculation of theaflavin and Cyanidin-3-Glucoside molecules as active material in Dye Sensitized Solar Cells using Density Functional Theory (DFT)

Dye-Sensitized Solar Cell (DSSC) is one of photovoltaic (PV) cell which converts solar energy into electrical energy, by using dye as its active material. In this study, total energy and bandgap energy of natural dyes such as theaflavin and cyanidin-3-glucoside (C3G) molecules were calculated using density functional theory (DFT) method via quantum espresso software. Optimization of some calculation parameters such as cutoff energy, pseudopotential and k-point have been done to ensure minimum total energy of dyes molecule. Based on the result, the total and bandgap energy of theaflavin is 10172.80 eV and 1.96 eV, while the total and bandgap energy of the C3G molecule is 8442.26 eV and 1.73 eV. From these results, further investigation is necessary to the opportunities of the two dyes as DSSC sensitizers.

A novel Ru (II) complex with high absorbance coefficient: efficient sensitizer for dye-sensitized solar cells

In this paper, a new sensitizer, Ru(4,4′-dicarboxy(phenylethenyl)-2,2′-bipyridine) (4,4′-bis(2-(4-tert-butyloxyphenyl) ethenyl)-2,2′–bipyridine) (NCS)2 with high absorbance coefficient denoting AJ-01, is introduced and its application in dye-sensitized solar cells (DSSCs) is investigated. The synthesized dye was characterized via various analytical methods, such as 1HNMR, 13CNMR, and UV–vis spectroscopic methods, and finally, it was utilized as a visible-light sensitizer in DSSCs. The AJ-01 photovoltaic performances were compared with that of N-719 as a commonly used sensitizer and were evaluated under similar conditions. UV–Vis absorption spectra for the AJ-01 sensitizer were also showed that the molar extinction coefficients much higher than the N-719 sensitizer at the peak wavelengths of the new sensitizer. Furthermore, Ab initio calculations were used to clarify the electronic properties and the role of the anchoring ligands at the rate of electron transfer to TiO2. The photovoltaic parameters of the AJ-01 sensitizer cell show an open-circuit voltage (Voc) of 0.764 V, short-circuit current density (Jsc) of 20.11 mA cm−2 and fill factor (F.F.) of 0.55, and a power conversion efficiency of 8.4%.