Chemical bath deposition of CdS quantum dots onto mesoscopic TiO2 films for application in quantum-dot-sensitized solar cells

Abstract

Alcohol, instead of water, was used as a solvent in a chemical bath deposition process for the in situ synthesis of CdS quantum dots onto mesoporous $\mathrm{Ti}{\mathrm{O}}_2$ films. Due to low surface tension, the alcohol solutions have high wettability and superior penetration ability on the mesoscopic $\mathrm{Ti}{\mathrm{O}}_2$ film, leading to a well-covered CdS on the surface of mesopores. The CdS-sensitized $\mathrm{Ti}{\mathrm{O}}_2$ electrode prepared using the alcohol system not only has a higher incorporated amount of CdS but also greatly inhibits the recombination of injected electrons. The efficiency of a CdS quantum-dots-sensitized solar cell prepared using the present method is as high as 1.84% under the illumination of one sun (AM1.5, $100\mathrm{mW}∕{\mathrm{cm}}^2$ ).