Chemical reactions in TiO2/SnO2/TiCl4 hybrid electrodes and their impacts to power conversion efficiency of dye-sensitized solar cells

This study examined the applicability of TiO₂/SnO₂/TiCl₄ hybrid electrodes in dye-sensitized solar cells (DSSCs) by combining chemical modeling with experimentation. The interfacial chemical reactions in a TiO₂/SnO₂/TiCl₄ system were simulated using a thermochemistry software package, which led to the design and testing of hybrid working electrodes. Chemical thermodynamic modeling proved that TiCl₄ is an effective agent in removing Tiⁿ⁺ (n<4) and Sn^m+ (m<4) ion impurities from dry-mixed TiO₂/SnO₂ composite particles. Our results demonstrate that the power conversion efficiency of DSSC with a TiO₂/SnO₂/TiCl₄ hybrid electrode exceeds that of the conventional DSSC with a TiO₂ electrode due to the effects of light-scattering and the formation of additional absorbance (SnCl₂), which is an unexpected side effect of TiCl₄ treatment enabling the absorption of visible light. The proposed approach is ideally suited to establishing relationships between chemistry theory and the structure and performance of advanced DSSCs as well as photo-electro-chemical systems.