Optimization of TiO2 photoanode films for highly efficient quantum dot-sensitized solar cells

As a fundamental part of quantum dot-sensitized solar cells, the composition and configuration of the TiO2 photoanode film plays an important role in photovoltaic performance. In this work, the preparation and optimization of films have been systematically studied, including the TiCl4 treatment technique, transparent layer and light-scattering layer thickness and composition. Experimental results show that the sole TiCl4 treatment on fluorine doped SnO2 (FTO) glass is sufficient for achieving a high efficiency in the resultant cell devices when compared with the simultaneous treatment on both FTO glass and TiO2 mesoporous films. The thickness and porosity of the transparent layer have been optimized by tuning the number of transparent layers and the ethyl cellulose contents in the paste. Moreover, the influence of the light-scattering layer pastes with different contents of the large-sized TiO2 particles on the performance of the cells has also been explored. The CdSe-sensitized solar cells based on the optimized TiO2 film photoanode exhibits a power conversion efficiency of 5.53% under 1 full sun illumination, which is among the best efficiencies for plain CdSe QD-based solar cells.