Improved CdS QDSSCs with graphene and anatase-rutile TiO2 composite as photoanodes

In this paper, we developed a simple and convenient method for incorporating graphene with anatase-rutile TiO 2 composite and applied it as photoanode to improve the photovoltaic performance of CdS QDSSCs. Our research indicated in a CdS QDSSC system, the photoelectric conversion efficiency (PCE) of anatase-rutile TiO 2 (TGr0) composite photoanode was 86% higher than that rutile TiO 2 NRs. We also found that the PCE increased first and then decreased with the change of graphene content after the graphene was introduced into the anatase-rutile TiO 2 photoanode. When the ratio of optimized graphene/anatase TiO 2 particles composite that spin-coated on rutile TiO 2 NRs photoanode was 5%, we attained a maximum PCE of 2.20%, which was 178% and 50% higher than that pure TiO 2 NRs (0.79%) and TGr0 (1.47%), respectively.