Improving charge transfer properties and solar cell performance by In-doped TiO2 as an efficient photoanode for dye-sensitized solar cells (DSSCs)

Abstract

Dye-sensitized-solar cells (DSSCs) are of great interest as cost-effective and green energy producers. The vastly explored photoanodes are one of the most significant parts of DSSC and still play a crucial role. We employed the fast and facile sol-gel technique to synthesize and dope TiO2 mesoporous structure with indium atoms. Although In doping in the TiO2 structure has been used previously, there have been few research on its application as photoanode in DSSCs. We investigated TiO2:In as an appropriate candidate for photoanode in DSSC and evaluated its charge transfer and optical, structural, and electrochemical properties. Mott-Schottky results show that indium doping can increase the carrier concentration up to 1.1 × 1017 cm−3 and elevate the conductivity as well as charge transfer properties. The optical and structural properties were investigated by PL, Raman, and UV–visible methods, and the results showed that TiO2:In has suppressed recombination in its structure. Also, In-doping improves the electrochemical properties of the photoanodes. The EIS results establish that In corporation can reduce the charge transfer resistance to 33 Ω cm2. The champion TiO2:In-based DSSC shows an 8.62 % efficiency, which indicates a 55 % improvement compared to the non-doped TiO2.