Improving the efficiency of dye-sensitized solar cells by photoanode surface modifications

Abstract

Dye-sensitized solar cells (DSSCs) provide a promising alternative solar cell technology because of their high efficiency, environmental friendliness, easy fabrication, and low cost. Power conversion efficiency is an important parameter to measure the performance of DSSCs, but the severe charge recombination that occurs at the photoanode hinders the future improvement of power conversion efficiency. Therefore, one of the key goals for achieving high efficiency is to reduce the energy loss caused by the unwanted charge recombination at various interfaces. From this perspective, surface modification of the photoanode is the simplest method among the various approaches available in the literature for enhancing the performance of DSSCs by inhibiting the interfacial charge recombination. After some brief notes on DSSCs, in this review, we present a comprehensive discussion on surface modifications of different photoanodes that have been adopted in the literature not only for reducing recombination but also for enhancing light harvesting. Depending on the electrode materials, we discuss surface modifications of binary oxides such as TiO2 and ZnO and ternary oxides, including Zn2SnO4, SrSnO3, and BaSnO3. We also talk about methods of surface modification and the materials suitable for surface treatment. Finally, we end with a brief future outlook of DSSCs.