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Dye-sensitized solar cells based on graphene oxide and natural plant dye extract
摘要： The world is advancing quickly in terms of population and technology and this has placed a high demand on energy. The exploitation of conventional sources of energy such as fossil fuel, has proven to be harmful to the environment and its biota. Consequently, there is a need to exploit clean, renewable and sustainable sources of energy like the sun. Dye-sensitized solar cells (DSSCs) have been of particular interest owing to their low price-to-performance ratio, relatively low cost of fabrication, availability of raw materials and eco-friendliness. The performance of the cell is highly dependent on the materials used for each of its components: the sensitizer, photoanode, counter electrode and the electrolyte. This work was carried out to study the photovoltaic properties of DSSCs based on TiO2-GO photoanodes sensitized with natural dye pigments. Graphene oxide (GO), synthesized from graphite by Hummer’s method, was incorporated into the photoanodes to study the effects of its varying composition on the photovoltaic performance of the cells. GO was incorporated into the photoanodes by forming a nanocomposite layer (GO-TiO2) onto a pristine TiO2 nanoparticle layer to form double-layer sensitized photoanodes. The synthesized GO was characterized by UV–vis spectroscopy showing an absorbance peak at 221 nm wavelength, characteristic of GO. Mimosa pudica dye, a chlorophyll dye, was extracted from the leaves of the photosensitive green plant to sensitize the photoanodes. The photovoltaic properties of the cells were evaluated by current density–voltage (JV) curves. Promising results were observed. Generally, the incorporation of GO in the double layer photoanodes enhanced the photovoltaic properties of the cells. This led to a 41% improvement in ef?ciency for 0.71 wt% GO double layer based DSSC compared to the single layer nanoparticle based DSSC. The highest ef?ciency was recorded for the double layer (DL) photoanode with 0.71 wt% GO composition (Voc = 0.284, Jsc = 16.085, FF = 0.00035, g = 0.1%). Furthermore, single-layer chlorophyll-sensitized photoanodes were compared with single-layer anthocyanin-sensitized photoanodes using Rhoeo spathacea and Hibiscus rosa-sinensis dye extracts. The highest ef?ciency was recorded for the TiO2/ Hibiscus rosa-sinensis (Voc = 0.468, Jsc = 0.039, FF = 0.485, g = 0.55%).
关键词： Dye-sensitized solar cells,Plant dye,Photovoltaic properties,Graphene oxide
更新于2025-09-19 17:13:59
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Lawsone isomers, lawsone ether and bilawsone for dye-sensitized solar cells applications: DFT and UV–Vis studies
摘要： Structural and optoelectronic properties of lawsone (L), lawsone ether (LE) and bilawsone (BL) were studied theoretically using the DFT and time-dependent DFT methods with hybrid functional B3LYP5 and 6-311G (2d,p) basis set. For the monomer lawsone molecule, isomerization reaction between two rotational isomers was analyzed based on a thermodynamic approach. The electronic spectra of the dyes molecules in a vacuum and solvents (DMSO and CH2Cl2) were computed. The maximum wavelengths were found at 355e408 nm for the LE and 350e448 nm for BL that indicated bands shift to visible range compared to L (340 nm). The UVeVis spectra of the L and BL were measured experimentally in DMSO solution. For the BL, a broad and intensive band was observed in a visible region at 452 nm that apparently would favour sensitizing ability of the dye. The optoelectronic properties of the LE and BL showed them as more promising candidates for DSSCs applications compared to the individual lawsone dye.
关键词： Lawsone ether,Dye-sensitized solar cells,Lawsone isomers,DFT/TD-DFT,Bilawsone,UVeVis/vibrational spectra
更新于2025-09-19 17:13:59
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Fabrication of Dye Sensitized Solar Cells by the Plasmonic Effect of Silver Nanoparticles and Basella Alba Dye
摘要： Dye-sensitized Solar cells are the most promising devices among third-generation solar cells because of low cost, easy production, environmental friendliness, and relatively high conversion efficiency. In this present work, the power conversion efficiency of dye-sensitized solar cell has been increased by incorporating silver nanoparticles into TiO2 photo anodes. TiO2 nanoparticles were prepared by sol-gel method. Silver nanoparticles were prepared by chemical reduction method. As prepared TiO2 nanoparticles were annealed at 300?c for 2h.TiO2 have been characterized by X-ray diffraction analysis. From XRD the average particle size was calculated as 49nm and it exhibits a tetragonal shape, and characterized by scanning electron microscopy confirms the spherical shape in nature. The silver nanoparticles were characterized by Scanning Electron Microscopy and UV-visible spectroscopy. From the characterisation results it was found that the silver nanoparticles are spherical in shape and shows the maximum absorption peak at 437nm. Organic dye from Basella Alba fruit extract was used and it was subjected to different temperatures and were coated on the cells. The prepared Solar cells were characterized by current-voltage (I/V) characteristics and efficiencies of Solar cells were calculated.
关键词： Silver Nanoparticles,Dye Sensitized Solar Cells,Basella Alba
更新于2025-09-19 17:13:59
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4H-pyranylidene organic dyes for dye-sensitized solar cells: Twisted structures towards enhanced power conversion efficiencies
摘要： Five sensitizers bearing a 4H-pyranylidene moiety have been synthesized. The incorporation of a thiophene ring (with different substituents in its position 5), in the exocyclic double bond of the previously reported SFO-346, leads to twisted structures of type 2D-π-A and D–(π–A)2 that minimize the π-π stacking of the dyes on the photoanode. Theoretical calculations confirm the tridimensional structure of the molecules. Moreover, the different electronic nature and bulkiness of the substituents modulate the optical and electrochemical properties of the sensitizers. A power conversion efficiency of 7.68% was obtained when the thiophene was substituted with a tert-butyl group (dye 16), the highest value reported, so far, for dyes based on a 4H-pyranylidene. That efficiency is mainly due to the high open circuit voltage observed (0.729 V) without using anti-aggregating additives.
关键词： 4H-pyranylidene,Dye-sensitized solar cells,Open circuit voltage,Thiophene
更新于2025-09-19 17:13:59
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Phthalocyanine-silver nanoparticle structures for plasmon-enhanced dye-sensitized solar cells
摘要： The localized surface plasmon resonance of silver nanoparticles (Ag NPs) was examined to improve the performance of phthalocyanine (MTXPc) in the plasmon-enhanced phthalocyanine-sensitized solar cells. When MTXPc dyes directly conjugated to Ag NPs (MTXPc-AgNPs) were used to sensitize solar cells, both of short-circuit current density (JSC) and open-circuit voltage (VOC) of phthalocyanine-sensitized solar cells were significantly increased. In the case of MTXPc conjugated to Ag@ZIF-8 (MTXPc-Ag@ZIF-8), slightly increasing in the JSC compared to alone MTXPc are observable but their VOC are significantly greater than alone MTXPc. Increasing in the JSC and VOC of the MTXPc-AgNPs and MTXPc-Ag@ZIF-8 lead to improve the performance of phthalocyanine in plasmon-enhanced phthalocyanine-sensitized solar cells compared to alone MTXPc. Also, the examination of the effect of the carboxyl- and sulfonyl-anchored dye (ZnTCPc-AgNPs and ZnTSPc-AgNPs, respectively) in conjunction with plasmonic NPs on the performance of DSSCs showed that ZnTCPc-AgNPs and ZnTSPc-AgNPs perform significantly better than their unsubstituted analogues. The studying the effect of the metal in the central cavity of phthalocyanine using zinc, manganese, iron, cobalt, and nickel showed that the metal in the central cavity of phthalocyanine has the critical role toward the photovoltaic performance of the plasmon-enhanced phthalocyanine-sensitized solar cells.
关键词： Plasmonic effect,Phthalocyanine,Dye-sensitized solar cells,Silver nanoparticle
更新于2025-09-19 17:13:59
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Effect of fluorine substituents on benzothiadiazole-based Da????a??Aa?2a????a??A photosensitizers for dye-sensitized solar cells
摘要： Two D–π–A0–π–A organic dyes with triazatruxene (TAT) as the electron donor, thiophene as the π-spacer, benzoic acid as the anchor group, and benzothiadiazole (BT) or difluorobenzo[c][1,2,5]thiadiazole (DFBT) as the additional acceptor, namely LS101 and LS102, respectively, were applied to dye-sensitized solar cells (DSSCs). As fluorine substituents are usually strong electron-withdrawing groups, introducing two fluorine atoms into BT was expected to strengthen the electron-withdrawing ability of the auxiliary acceptor, resulting in DSSCs with a broader light capture region and further improved power conversion efficiency (PCE). Fluorine is the smallest electron-withdrawing group with an induction effect, but can also act as an electron-donating group owing to its conjugation effect. When the conjugation effect is dominant, the electron-withdrawing ability of additional acceptor DFBT decreases instead. Accordingly, the band gap of LS102 was broadened and the UV-vis absorption spectrum was blue-shifted. In the end, DSSCs based on LS101 achieved a champion PCE of 10.2% (Jsc = 15.1 mA cm?2, Voc = 966 mV, FF = 70.1%) while that based on LS102 gave a PCE of only 8.6% (Jsc = 13.4 mA cm?2, Voc = 934 mV, FF = 69.1%) under standard AM 1.5G solar irradiation (100 mW cm?2) with Co2+/Co3+ as the electrolyte.
关键词： Power conversion efficiency,Fluorine substituents,Organic photosensitizers,Benzothiadiazole,Dye-sensitized solar cells
更新于2025-09-19 17:13:59
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In Depth Analysis of Photovoltaic Performance of Chlorophyll Derivative-Based a??All Solid-Statea?? Dye-Sensitized Solar Cells
摘要： “all solid-state” dye-sensitized solar cells (DSSCs) with chlorophyll derivatives were integrated into a mesoporous TiO2 electrode and 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene as the hole-transport material. Despite modest power conversion efficiencies (PCEs) between 0.26% and 0.55% achieved for these chlorin dyes, a systematic investigation was carried out in order to elucidate their main limitations. To provide a comprehensive understanding of the parameters (structure, nature of the anchoring group, adsorption . . . ) and their relationship with the PCEs, density functional theory (DFT) calculations, optical and photovoltaic studies and electron paramagnetic resonance analysis exploiting the 4-carboxy-TEMPO spin probe were combined. The recombination kinetics, the frontier molecular orbitals of these DSSCs and the adsorption efficiency onto the TiO2 surface were found to be the key parameters that govern their photovoltaic response.
关键词： EPR,chlorophyll,spirulina,solid state dye sensitized solar cells,anchoring groups
更新于2025-09-19 17:13:59
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Bi2S3 nanoparticles densely grown on electrospun-carbon-nanofibers as low-cost counter electrode for liquid-state solar cells
摘要： Dye-sensitized solar cells (DSSCs) counter electrode (CE) is needed to have both good electrical conductivity and high catalytic activity, and composite materials are better meet these two requirements. In this work, Bi2S3/carbon nanofiber (CNFs) composites are synthesized by simple electrospinning and hydrothermal methods, and after optimization of the content of Bi2S3, the large amount Bi2S3 nanoparticles are grown densely on CNFs without agglomeration. Bi2S3/CNFs composites are first introduced into DSSCs as CE. The optimized Bi2S3/CNFs composites are of great electrochemical performance and obtain a photoelectric conversion efficiency (PCE) of 7.64 %, which is better than common used Pt CE (7.12 %). Thus Bi2S3/CNFs CE has great prospects based on low cost and simple fabrication process to develop Pt-free CEs which could accelerate the large-scale application of DSSCs.
关键词： Counter electrode,Bi2S3 nanoparticles,Carbon nanofibers,Composite,Dye-sensitized solar cells
更新于2025-09-19 17:13:59
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Bis-Cyclometalated Iridium Complexes Containing 4,4a?2-Bis(phosphonomethyl)-2,2a?2-bipyridine Ligands: Photophysics, Electrochemistry, and High-Voltage Dye-Sensitized Solar Cells
摘要： In this report, the synthesis and characterization of two bis-cyclometalated iridium(III) complexes are presented. Single-crystal X-ray diffraction shows [Ir(ppy)2(4,4′-bis(diethylphosphonomethyl)-2,2′-bipyridine)]PF6 adopts a pseudo-octahedral geometry. The complexes have an absorption feature in the near-visible?UV region and emit green light with excited-state lifetimes in hundreds of nanoseconds. The redox properties of these complexes show reversible behavior for both oxidative and reductive events. [Ir(ppy)2(4,4′-bis(phosphonomethyl)-2,2′-bipyridine)]PF6 readily binds to metal oxide supports, like nanostructured SnIV-doped In2O3 and TiO2, while still retaining reversible redox chemistry. When incorporated as the photoanode in dye-sensitized solar cells, the devices exhibit open-circuit voltages of >1 V, which is a testament to their strength of these iridium(III) complexes as photochemical oxidants.
关键词： high-voltage,dye-sensitized solar cells,bis-cyclometalated iridium(III) complexes,electrochemistry,photophysics
更新于2025-09-19 17:13:59
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Effect of fluoro-substituted acceptor-based ancillary ligands on the photocurrent and photovoltage in dye-sensitized solar cells
摘要： Herein, we report four novel heteroleptic ruthenium (II) complexes, namely SD-7 to SD-10, containing fluoro- and trifluoro- methyl antennas as substituents on the ancillary ligands for dye-sensitized solar cells, and were compared to the benchmark dye N719. Photosensitizers (dyes) SD-7 to SD-10 were synthesized according to a typical one-pot three-step procedure with the corresponding ancillary ligands (LS-7 to LS-10). All the dyes were characterized by ATR-FTIR, 1H NMR and mass spectrometry. Furthermore, the photophysical, electrochemical and photovoltaic performances were compared with N719. The band gaps, ground and excited state oxidation potentials were measured. The photovoltaic performance of the dyes showed that SD-7 with five fluorine atoms and SD-8 with eCF3 at the –ortho position of the phenyl moiety outperformed the benchmark dye N719 with the efficiencies of 8.03% and 8.17%, respectively, with current density of 19.57 and 19.46 mA?cm?2, respectively, and open-circuit voltages of 0.65 V and 0.69 V, respectively, under optimized conditions. The fabricated solar devices at lab-scale showed a systematic trend of decreasing JSC when the fluoro-substituted dyes were sensitized on TiO2: SD-7 (with five –F) > SD-8 (with one eCF3 at ortho position) > SD-9 (with one eCF3 at para position) > SD-10 (with two eCF3, one at ortho and one at para position). This can be attributed to the greater number of fluorine atoms directly attached to sp2 hybridized carbon atoms, which greatly enhanced the dipole moment and intimate electronic coupling of SD-7 with TiO2 nanoparticles leading to better photocurrent density.
关键词： Fluoro-based dyes,Acceptor-based ancillary ligand,Photovoltaic performance,Dye-sensitized solar cells,Ruthenium complex
更新于2025-09-19 17:13:59