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Enhanced photovoltaic performance of dye-sensitized solar cells based on electrodeposited sulfur-doped MSex (M=Co, Ni) films
摘要： Rational design of ternary transition metal sulfoselenide films by an electrodeposition technique remains a critical challenge to further improve their catalytic activity. This study reports a fabrication approach of sulfur-doped MSex (M ? Co, Ni) films, which are directly employed as efficient counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The morphology and electronic structure of sulfur-doped MSex films are controlled by adjusting the molar ratio of S/Se in their electrodeposition solutions. It is found that sulfur-doped MSex films exhibit favorable electrocatalytic activity for the reduction of I3, owing to their more exposed activity sites and strong charge-transfer capability. Furthermore, the DSSC fabricated with the optimized sulfur-doped CoSex (sulfur-doped NiSex) CE has achieved the highest power conversion efficiency (PCE) of 7.44% (7.54%) than that of the DSSC fabricated with platinum (Pt) CE (6.38%). The results demonstrate that sulfur-doped MSex films have been applied as the attractive low-cost CEs with outstanding electrocatalytic activity for DSSCs.
关键词： Counter electrodes,Activity sites,CoSex,Electrodeposition technique,Sulfur doping,NiSex
更新于2025-09-11 14:15:04
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Copper-Doped Iron Carbide as Counter Electrodes for Dye- Sensitized Solar Cells
摘要： A facile method of pyrolysis of 2-methyl imidazole is used to prepare copper-doped iron carbide materials as counter electrodes for dye-sensitized solar cells. The content of copper in copper doped iron carbide materials are: 0.25%, 0.5%, 0.75%, 1% (molecular proportion). Among these DSSCs made from different Cu content Fe3C cathodes, the Fe3C-0.75%Cu based on the Cu content of 0.75% counter electrode yields the highest energy conversion efficiency of 5.68%. Compared to the Pt/C- based DSSC (6.22%), the DSSC fabricated from Fe3C-0.75%Cu has a similar η. To evaluate the chemical catalysis of copper-doped iron carbide counter electrodes toward reduction, cyclic voltammetry and electrochemical impedance spectra are carried out to characterize the counter electrodes. All the results have revealed that doped with copper can improve the catalytic ability of iron carbide counter electrodes. And the copper doped iron carbide counter electrode owns low prices of raw materials, simple production process, so it has very wide application prospects.
关键词： iron carbide,counter electrodes,DSSC,copper-doped
更新于2025-09-11 14:15:04
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Electronic Structures and Catalytic Activities of Niobium Oxides as Electrocatalysts in Liquid Junction Photovoltaic Devices
摘要： Two types of nanosized niobium oxides and their composite: pseudo-hexagonal Nb2O5 (TT-Nb2O5), monoclinic NbO2 (M-NbO2) and the coexistence of TT-Nb2O5 and M-NbO2 (TT-Nb2O5/M-NbO2) are successfully synthesized through the urea-metal chloride route, and they exhibit excellent catalytic activity and photovoltaic performance in dye-sensitized solar cells (DSSCs). First-principles density function theory (DFT) calculations show that their catalytic activity is significantly influenced by their intrinsic electronic structures and properties. The lone-pair 4d1 electrons of Nb4+ in M-NbO2 enhance the Nb-I interaction and promote the electron transfer from the M-NbO2 counter electrode (CE) to I, and thus resulting in superior catalytic properties in M-NbO2 based DSSCs. In addition, the adsorption energy of I on the M-NbO2 surface is in the optimal energy range of 0.3?1.2 eV, and the Fermi level of M-NbO2 is 0.6 eV, which is higher than the I3? reduction reaction (IRR) potential and I3? can be spontaneously reduced to 3I?. This work provides a general strategy for understanding the electronic structures and catalytic activities of transition metal compounds as CE catalysts for DSSCs.
关键词： electrocatalytic activity,counter electrodes,first-principles DFT calculations,dye-sensitized solar cells,niobium oxides
更新于2025-09-11 14:15:04