Sensitizers For Dye-sensitized Solar Cells Research Articles

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%.

Enhancement of dye-sensitized solar cell efficiency through co-sensitization of thiophene-based organic compounds and metal-based N-719

Synthesis of five novel thiophene-based metal-free organic dyes, named IS1-5, to study their photophysical, electrochemical properties and photovoltaic performance as sensitizers and co-sensitizers for DSSCs. Dyes IS-5 are cyanoacetanilide derivatives, which are distinguishedby theirsmall size, the simple preparation method, and the presence of multiple anchoring species (CO and CN) within their molecular structure. From their UV/Vis. spectra, IS-4 and IS-5 displayed the highest molar extinction coefficient with a bathochromic-shift to the intramolecular charge transfer band. In addition, to recognize the potential of HOMO level and the potential of LUMO level among all IS1-5 dyes, the cyclic voltammetry technique must be used. Their characteristics assert that all dyes possess the qualifications essential to be used as a sensitizer for dye-sensitized solar cells (DSSCs). Interestingly, over co-sensitization, all dyes showed better photovoltage values (VOC) than the standard dye N-719. Among Dyes IS1-5, co-sensitizer IS-5 showed the highest photoconversion efficiency (η) of (8.09%) compared to the standard dye N-719 (7.61%). Moreover, electrochemical impedance spectroscopy (EIS) asserts the impact of this dye on improving charge transfer in TiO2. Finally, density functional theory (DFT) has been studied for dyes IS1-5 using Guassian09 software and the outcomes comfortably agree with experimental results.

Enhanced Photovoltaic Performance Of Dye-Sensitized Solar Cells Via Sensitization Of Nanocrystalline Tio 2films With Metal -Free Indoline Dye

D149, a metal-free indoline dye, is one of the most promising sensitizers for dye-sensitized solar cells (DSSCs). The D149 sensitizer with the solvent acetonitrile gives two distinct absorption bands: first band is in the region of 350-430 nm due to (π–π*) electron transitions of the conjugated molecules, and the next in the region of 430-614 nm can be allocated to an intermolecular charge transfer (ICT) between the electron-donor and electron-acceptor anchoring moieties.Upon optimization, the device given a Jsc of 13.2mA/cm2, Voc of 752mV, and FF of 0.749 % and the conversion efficiency of 7.4%.

Dye extracted from Costus woodsonii leave as a natural sensitizer for dye-sensitized solar cell

Current work employs dye extracted from leaves of Costus woodsonii as a new sensitizer for dye-sensitized solar cells (DSSCs). The leave was extracted in three different solvents namely ethanol, methanol, and acetone. Extraction of leaves was carried out by the freezing method. DSSCs with the configuration of TiO2/dye/electrolyte/Pt were assembled. The dyes in DSSCs were Costus woodsonii leaves extracted in methanol, ethanol, and acetone. DSSC with methanol extract of leaves has an efficiency of 0.23 % and short-circuit current density (Jsc) of 0.63 mA cm-2. DSSC sensitized with ethanol extract of leaves has an efficiency of 0.37 % and Jsc of 0.85 mA cm-2. DSSC sensitized with acetone extract of leaves shows the highest efficiency of 0.48 % and Jsc of 1.35 mA cm-2. The performance of the DSSCs in this work is compared with other natural dye-based DSSCs. The efficiency obtained in this work is better or at par with the works reported by other researchers.
 Keywords: Natural dye; Costus woodsonii; Leave; Dye-sensitized solar cells

Acceptor substituent effect on triphenylamine-based organic dye sensitizers for DSSCs: quantum chemical study

In this work, a series of triphenylamine (TPA)- based dye molecules (A1–A5) for dye-sensitized solar cells (DSSCs) application has been designed and screened. The electron donor contains TPA, thieno[3,2-b]thiophene, as the π-bridge, cyanoacrylic acid as electron acceptor based on donor–π-spacer–acceptor (D-π-A) as reference dye (3a). In order to enhance the tuning, effect of acceptor moieties was investigated at 3a dye. The electron acceptor effect of the substituent on the absorption spectra and photovoltaic (PV) properties has been investigated by the combination of density functional theory (DFT) and time-dependent DFT (TD-DFT) method approaches. Different exchange-correlation (XC) functionals were initially evaluated in order to establish a proper methodology for calculating the excited state energy of the 3a dye. Consequently, TD-ωB97XD method and 6-31G(d) basis set have used the comparison of experimental value. From the calculated results, it was concluded that the A4 (PO3H2) and A5 (SO2H) dyes are strongly grouped for more red-shift and electrons injected into semiconductor the conduction band edge of TiO2 was successful. It is expected that our research will pave a new method to design efficient organic D-π-A dye sensitizers in DSSCs.

Natural dyes from amazon forest: potential application in dye-sensitized solar cells

ABSTRACT In this work, plant dyes extracted from Amazon Forest are applied as a sensitizer in Dye-Sensitized Solar Cells. The selected plants were Euterpe oleracea, Arrabidaea chica, Bixa orellana, Genipa Americana, and Myrcia sylvatica, and the dyes were collected from fruits, leaves, seeds, pulp and seeds and stalk scrapings respectively. Characterization studies by the UV-vis spectroscopy made it possible to know the absorption spectra of each plant dye, and the X-ray diffraction technique allows the structural characterization of the nanostructured semiconductor layer. The solar cells were characterized according to their efficiency parameters (Voc, Jsc, FF and ? (%)), obtained from the current vs voltage curves. Such parameters proved to be modest, presenting Voc and Jsc values over 0.334 volts and 0.452 mA/cm2 for a photosensitized cell with the dyes extracted from Genipa americana. In this way, it was possible to verify the photoelectrochemical potential of the dyes extracted from plants of the Amazon Forest.

Indole fused heterocycles as sensitizers in dye-sensitized solar cells: an overview

The past three decades have witnessed extensive research in developing a range of non-metallic fused heterocyclic organic dyes for dye sensitized solar cells (DSSCs).

Structural features of indoline donors in D–A-π-A type organic sensitizers for dye-sensitized solar cells

Novel D–A-π-A organic sensitizers for DSSCs based on benzothiadiazole internal acceptor (A) and N-substituted indolines fused with cyclopentane or cyclohexane as donor (D) with the best PCE of 5.8% were reported.

Phenothiazine and phenoxazine sensitizers for dye-sensitized solar cells – an investigative review of two complete dye classes

A compete statistical review of phenothiazine DSSC dyes, identifying the traits of successful phenothiazine dyes and uncovering inherent molecular limitations.

Double anchor indolo[3,2-b]indole-derived metal-free dyes with extra electron donors as efficient sensitizers for dye-sensitized solar cells

New di-acceptors organic dye with extra electron donors shows an enhanced PCE of 7.86% comparing to parent one.

Carbazol-phenyl-phenothiazine-based sensitizers for dye-sensitized solar cells

Heteroaromatic units are commonly used as π-spacers for sensitizers and show significant roles in tuning molecular properties and DSSCs performances.

β-Functionalized push–pull opp-dibenzoporphyrins as sensitizers for dye-sensitized solar cells: the push group effect

β-Functionalized push–pull opp-dibenzoporphyrins with different donor groups were designed and synthesized, showing a significant push–pull effect. High power conversion efficiencies were achieved with these sensitizers in DSSCs.

Photophysical properties of N719 and Z907 dyes, benchmark sensitizers for dye-sensitized solar cells, at room and low temperature.

Two benchmark sensitizers used for dye-sensitized solar cells, ruthenium polypyridyl N719 and Z907 dyes were investigated with spectroscopic methods as steady-state absorption, time-gated phosphorescence and femto-/nanosecond time-resolved transient absorption at room temperature and at 160 K. Aim of this study was to perform comprehensive photophysical study of dye excited singlet and triplet metal-to-ligand charge transfer (MLCT) states including states lifetimes, dependency on temperature and dye concentration and obtain detailed information on the excitation decay pathway. Transient absorption and phosphorescence decay data provided a clearer picture of the dynamics of the excited MLCT states. Based on data analysis, the excitation decay pathway consists of rapid intersystem crossing to the triplet MLCT state that undergoes state solvation and vibrational relaxation. It was demonstrated that the lifetime of the fully relaxed triplet MLCT is also strongly dependent on dye concentration for both molecules, providing a viable explanation for a large inconsistency seen in previous studies.

Accelerated discovery of boron-dipyrromethene sensitizer for solar cells by integrating data mining and first principle

Boron-dipyrromethene (BODIPY) is one promising class of sensitizers for dye-sensitized solar cells (DSSCs) due to unique merits of high absorption coefficient and versatile structural modification capability. However, such derivatives usually suffer from limited power conversion efficiencies (PCEs) because of narrow light absorption band and low electron injection. To aid the discovery of BODIPY sensitizers, we employ an inverse design method to design efficient sensitizers by integrating data mining and first-principle techniques. We establish robust data-mining models using genetic algorithm and multiple linear regression, where the features are filtered from 5515 descriptors and their meanings are explicitly explored for next inverse designs. Based on the features’ understanding, we design candidates NH1-6 and predict their PCEs, demonstrating remarkable enhancements (58% maximum) compared to previous works. Furthermore, their optoelectronic properties including maximum absorption wavelengths, oscillator strengths, bandgaps, transferred charges, charge transferred distances, TiO2 conduction band shifts, short-circuit currents and electron injection efficiencies simulated via first-principle calculations indicate significant increasements (93 nm, 122.41%, 23.70%, 36.36%, 471.17%, 63.64%, 28.55%, 107.86% maximum), which testifies the corresponding highly predicted PCEs and may overcome BODIPY dyes’ shortcomings. The as-designed BODIPY sensitizers can be promising candidates for DSSCs, and such method could help accelerate the discovery of other energy materials.