Study on photo-induced charge transfer properties in CdS quantum-dot-sensitized mesoporous TiO2 photoelectrode

In this study, well-crystallized mesoporous anatase TiO2 spheres (TiO2-MS) were prepared via a simple sol–gel process followed by subsequent hydrothermal treatment and then used as photoelectrode for quantum-dot-sensitized solar cell (QDSC) application. The mesoporous structure exhibits efficient QD loading and good light-scattering properties for light harvesting. In the meantime, both surface photovoltage technique based on lock-in amplifier and transient photovoltage measurement reveal that the QDs-sensitized mesoporous TiO2 sphere photoelectrode is conducive to promote the separation of photo-induced charges and reduce the charge recombination owing to the efficient charge transfer. As a result, the QDSCs based on mesoporous TiO2 spheres photoelectrode shows a power conversion efficiency of 1.34 %, which is significantly higher than that derived from P25 nanoparticle electrode. The relation between the performance of QDSCs and their photovoltage characterization was also discussed.