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Direct comparison of dithienosilole and dithienogermole as π-conjugated linkers in photosensitizers for dye-sensitized solar cells
摘要： Dithienosilole (DTS) and dithienogermole (DTG) are useful building units of π-conjugated organic materials. In the present work, donor–π-acceptor (D–π-A) dyes with bis(dihexyloxyphenyl)aminophenyl, DTS or DTG, and pyridine or cyanoacrylic acid as the donor (D), the π-conjugated linker (π), and the acceptor (A) units, respectively, were prepared and their optical properties were investigated. The D–π-A dyes exhibited strong absorption in the visible region, indicating efficient intramolecular donor–acceptor interaction. The addition of trifluoroacetic acid to solutions of pyridine-containing dyes led to red-shifts of the absorption bands as a result of pyridinium salt formation. Similar red-shifts were observed for cyanoacrylic acid dyes, which were due to the enhanced formation of neutral dyes relative to the separated ion pairs. The D–π-A dyes, however, showed similar absorption spectra when attached to the TiO2 surface, indicating that the dye–TiO2 electronic interaction was rather weak. In contrast to the finding that these dyes exhibited similar optical properties regardless of the π-linker (i.e., DTS or DTG), dye-sensitized solar cells (DSSCs) based on DTG-containing dyes exhibited superior performance compared to those based on DTS-containing dyes. Electrochemical impedance spectroscopy measurements supported the higher performance of the DSSCs with DTG-containing dyes.
关键词： π-conjugated linkers,Dithienosilole,Dithienogermole,Dye-sensitized solar cells,Photosensitizers
更新于2025-09-16 10:30:52
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Dye-sensitized solar cells using fluorone-based ionic liquids with improved cell efficiency
摘要： Dye-sensitized solar cells using fluorone-based ionic liquids with improved cell efficiency. Six trihexyltetradecylphosphonium chloride (P6,6,6,14Cl) based ionic liquids (IL) with dianionic fluorone derivatives were synthesized with total exchange of chloride from the dianionic dye: Fluorescein (a), Rose Bengal (b), Phloxine B (c), Eosin B (d), Eosin Y (e) and Erythrosin B (f). Spectroscopic characterization of these viscous salts indicated the presence of the expected 1 or 2 strong absorption bands. A total of 12 compounds, as sodium (from a to f) or as trihexyltetradecylphosphonium dianion salts (from a0 to f0), were used for sensitization of nanocrystalline TiO2. Here, we report the sensitization activity of these metal free dyes in terms of current–potential curve, open-circuit potential, fill factor, and overall solar energy conversion efficiency which have been evaluated under 100 mW cm?2 light intensity. We developed a strategy to improve the light harvesting of these conventional dyes by simple cationic exchange which was accompanied by a minimum of 30% increase in the cell photovoltaic conversion efficiency. Also, for Eosin B the binding to TiO2 apparently allows reduction of the –NO2 electron-withdrawing group to –NO2?. This provides a new interaction between the reduced nitro group and the TiO2 surface, reflecting an improvement in the overall DSSC performance reaching its maximum of 0.65% efficiency after light DSSC soaking. Factors that improve DSSC performance like aggregate inhibition, increment of the electrode's quasi-Fermi level and slight red shift in the absorption spectra of the tested anionic dyes were achieved by simple cationic exchange.
关键词： TiO2 sensitization,Cationic exchange,Photovoltaic conversion efficiency,Fluorone-based ionic liquids,Dye-sensitized solar cells
更新于2025-09-16 10:30:52
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Role of long persistence phosphors on their enhancement in performances of photoelectric devices: in case of dye-sensitized solar cells
摘要： To enhancing enhanced sunlight harvesting, long persistence phosphor (LPP) materials were often incorporated into photoanodes of photoelectric devices. However, the role of LPP layer on the photoelectric enhancements is not yet clear. Here, the authors have systematically studied the effect of green LPP (SrAl2O4: Eu3+) and its thickness on photoelectric behaviours of dye-sensitized solar cells (DSSCs). Results showed that the P25/LPP DSSCs generates power conversion efficiency (PCE) of 7.16 % at the optimal LPP thickness, which is 24.3% higher than that of the P25 ones. Series of analysis indicate that the enhancements in short-circuit current density and PCE could mainly be due to the LPP’s function of back scattering (containing down-conversion effect and enhancement in light absorption) of incident sunlight. Moreover, the enhanced carriers’ lifetime and open-circuit voltage are mainly due to the LPP layer’s afterglow effect. In addition, the P25/LPP DSSCs can still generate an output power density (82.15 μW cm-2) with a high PCE value of 46.94% in dark.
关键词： Back scattering,Power conversion efficiency,Down conversion,Long persistence phosphors,Titanium dioxide (P25),Dye-sensitized solar cells
更新于2025-09-16 10:30:52
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Platinum counter electrodes for dye-sensitized solar cells prepared by one-step dipping process
摘要： When designing counter electrodes (CEs) to enhance the performance of dye-sensitized solar cells (DSSCs), facile routes are important features. Platinum (Pt) metal is one of the most-promising CE designs for DSSCs. Herein, we developed a simple, and cost-effective one-step dipping process for preparing Pt CEs in DSSCs. The Pt CEs were prepared by dipping fluorine-doped tin oxide (FTO) in a 3-mercaptopropyl triethoxysilane (MTS)-Pt suspension. We tested and compared MTS-1-Pt, MTS-10-Pt, and sputtered-Pt as CEs in DSSCs. MTS-1-Pt and MTS-10-Pt refer to samples prepared with 1 and 10 ml of MTS, respectively. DSSCs with MTS-1-Pt CEs exhibited power conversion efficiency (PCE) values as high as 8.28%, which was superior to the DSSCs using MTS-10-Pt as the CEs (1.61%). Additionally, the DSSCs with MTS-1-Pt CE showed mostly similar PCEs compared to those with sputtered-Pt (8.55%) because of the same catalytic activity with iodide. Thus, this modified Pt CE facile process can be used to further enhance the performance of DSSCs.
关键词： one-step dipping process,catalytic activity,power conversion efficiency,Platinum counter electrodes,dye-sensitized solar cells
更新于2025-09-16 10:30:52
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Effect of organic dyes and polypyrrole on the efficiency of dye-sensitized solar cells
摘要： Polypyrrole films were coated on conductive glass by electrochemical deposition (alternative current of direct process). They were then used as the dye-synthesized solar cell counter electron electrodes. Scanning electron microscopy revealed that polypyrrole forms a nanoparticle like structure on the conductive glass. In the present study, two new organic dyes based on aniline and substituted 5-Nitrosalicylaldehyde with aniline were prepared and used and sensitizes in dye-sensitized solar cells. These dyes in solution and on a nano-anatase v2o5 substrate were investigated. Additionally, oxidation potential measurement were also carried out. Finally, dye-sensitized solar cells were fabricated to determine and conversion efficiency of each dye.
关键词： FESEM,Cyclic Voltammetry,FT-IR,Dye-sensitized solar cells,UV Spectroscopy,XRD,Nitrosalicylaldehyde-aniline
更新于2025-09-16 10:30:52
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A Rapid Synthesis of Vertically Aligned Taper-Like K-Doped ZnO Nanostructures to Enhance Dye-Sensitized Solar Cell Efficiency
摘要： Large-scale K-doped ZnO nanotapers were successfully grown on an indium tin oxide (ITO) substrate using a facile electrochemical route. The structural and morphologic analysis exhibited that the K-doped ZnO nanostructures had a nanotaper morphology and strong preferential [0001] c-axis direction with a hexagonal polycrystalline structure. The optical results show that the incorporation of K+ ions as the donors in a ZnO lattice leads to substantial modulation of the band gap structure of ZnO nanotapers, which results in a redshift in the ultraviolet emission peaks. The considerable enhancement of performance in K-doped ZnO-based dye-sensitized solar cells (DSSCs) can be related to the doping structure, which leads to higher dye loading (3.34 9 10(cid:2)8 mol/cm2). The good photovoltaic behavior of the K-doped ZnO nanotapers can be attributed to the higher surface-to-volume ratio and large K-doped ZnO nanotaper/ITO interfacial band bending, indicating the potential of a low-temperature aqueous electrochemical approach to synthesizing doped ZnO nanotapers for DSSCs.
关键词： K-doped ZnO,nanotapers,dye-sensitized solar cells,electrochemical route,band gap modulation
更新于2025-09-16 10:30:52
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SiNW/C@Pt Arrays for High-Efficiency Counter Electrodes in Dye-Sensitized Solar Cells
摘要： Modern energy needs and the pressing issue of environmental sustainability have driven many research groups to focus on energy-generation devices made from novel nanomaterials. We have prepared platinum nanoparticle-decorated silicon nanowire/carbon core–shell nanomaterials (SiNW/C@Pt). The processing steps are relatively simple, including wet chemical etching to form the silicon nanowires (SiNWs), chemical vapor deposition to form the carbon shell, and drop-casting and thermal treatment to embed platinum nanoparticles (Pt NPs). This nanomaterial was then tested as the counter electrode (CE) in dye-sensitized solar cells (DSSCs). SiNW/C@Pt shows potential as a good electrocatalyst based on material characterization data from Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Raman spectroscopy shows that the surface reactivity of the SiNW/C is increased by the decoration of Pt NPs. These data also show that the carbon shell included both graphitic (sp2 hybridization) and defective (sp3 hybridization) phases of carbon. We achieved the minimum charge-transfer resistance of 0.025 ? · cm2 and the maximum ef?ciency of 9.46% with a symmetric dummy cell and DSSC device fabricated from the SiNW/C@Pt CEs, respectively.
关键词： core–shell,defective carbon,electrocatalytic activity,dye-sensitized solar cells (DSSCs),counter electrodes (CEs),silicon nanowires (SiNWs)
更新于2025-09-16 10:30:52
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The fabrication of graphene-polypyrrole composite for application with dye-sensitized solar cells
摘要： This research is to study the preparation of graphene-monodispersed polypyrrole composite materials for uses as a counter electrode in dye-sensitized solar cells (DSSCs). The preparation started with the synthesis of graphene oxide (GO), followed by the preparation of composite films by polymerization method and the GO reduction process by ascorbic acid. The characterizations included thermal-gravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR), raman spectroscopy, X-ray diffraction (XRD), field-emission electron microscopy (FESEM) and cyclic voltammetry (CV). The DSSCs’ efficiency tests were also conducted and analyzed. Based on the test results, it was found that DSSCs prepared from PPy/RGO-5 composite films with 5% by weight of reduced graphene oxide (RGO) could give an optimal efficiency. Nevertheless, the efficiency of such solar cells was much less than that of DSSCs with platinum counter electrode. This could be due to incomplete reduction of graphene oxide, resulting low electron transfer ability and electrocatalytic activity toward the reduction of electrolyte solution.
关键词： Reduced graphene oxide,Polypyrrole,Dye-sensitized solar cells,Counter electrode
更新于2025-09-16 10:30:52
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Solar cells sensitized by porphyrin dyes containing a substituted carbazole donor with synergistically extended absorption and suppressed the dye aggregation
摘要： To achieve high power conversion efficiencies (PCEs), three porphyrin sensitizers have been synthesized and explored to simultaneously enhance the photocurrent (Jsc) and photovoltage (Voc). On basis of the XW4, a benzothiadiazole (BTD) unit has been introduced to afford XW57 with the aim to extend the absorption wavelength and enhance the light harvesting ability. As a result, a Jsc of 13.72 mA/cm2 has been obtained for XW57, higher than that of XW4. On this basis, XW58 has been prepared by modifying the carbazole-based donor with two bulky dihexyloxyphenyl groups, and the superior anti-aggregation character raises the Voc from 781 mV (XW4) to 844 mV. When both the BTD unit and the bulky groups are introduced to the acceptor and donor units, respectively, the resulting sensitizer XW59 exhibits a highest PCE value of 7.34% with synergistically enhanced Jsc of 13.19 mA/cm2 and Voc of 793 mV. These results provide further insight into developing high performance dye-sensitized solar cells.
关键词： Sensitizers,Bulky groups,Porphyrin,Carbazole,Dye-sensitized solar cells
更新于2025-09-16 10:30:52
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Bimetallic PtSe nanoparticles incorporating with reduced graphene oxide as efficient and durable electrode materials for liquid-junction photovoltaic devices
摘要： In this work, we introduce the synthesis of PtSe alloys with the different stoichiometric ratio of Pt and Se in PtSe alloy on reduced graphene oxide (RGO). And, then the developed nanohybrid materials are employed for the first time as counter electrodes (CEs) for efficient third-generation solar cells. As a result, PtSe nanoalloys is located on the surface of RGO without any agglomerations. Furthermore, the developed materials also provide a porous three-dimensional network structure, suggesting rapid electron transfer paths. Therefore, the highest efficiency of 6.26% was obtained for a cell fabricated with Pt0$74Se0.26/RGO electrode that is due to the lowest charge-transfer resistance of 0.89 U and diffusion impedance of 0.88 U. The optimized efficiency is also higher than those of 4.98% and 4.34% for devices assembled with Pt/RGO and Se/RGO CEs, respectively. This work presents a general strategy for designing and fabricating porous PtSe alloy/RGO CEs for energy conversion devices.
关键词： PtSe/graphene,Hybrid materials,Counter electrode,Dye-sensitized solar cells
更新于2025-09-16 10:30:52