Photoelectrical properties of CdS/CdSe core/shell QDs modified anatase TiO2 nanowires and their application for solar cells

Abstract

Anatase TiO₂ nanowire (NW) films modified with inverted type-I CdS/CdSe core/shell structure QDs have been successfully prepared by the post synthesis ligand-assisted technique. Surface photovoltage (SPV), transient photovoltage (TPV) and transient photocurrent (TPC) measurements demonstrate that CdS/CdSe core/shell structure QD-sensitized TiO₂ NWs electrodes favor photoexicited electron injection and charge transfer due to the special photo-electronic features of CdS/CdSe core/shell structure QDs. With a polysulfide electrolyte, the maximum conversion efficiency was 2.18% for CdS/CdSe QDs with the CdSe shell being 4.4 nanometers thick; a PCE of 0.07% for CdS QDs and a PCE of 0.63% for CdSe QDs were obtained under illumination at 100 mW cm⁻². The results reveal that the CdS/CdSe core/shell structure QDs sensitized TiO₂ NW electrodes have promising applications in solar cells.