Band energy modulation on Cu-doped Sb2S3-based photoelectrodes for charge generation and transfer property of quantum dot–sensitized solar cells

Abstract

Sb2S3 quantum dot is prepared as the optical absorber on the ZnO nanorod films to fabricate high-efficiency quantum dot–sensitized solar cells. The band energy of the solar cells is modulated by the different concentration of Cu-doping. Meanwhile, the optical absorption spectra and photoluminescence spectra of different ZnO/Sb2S3 photoelectrodes are investigated, which had exhibited the enhancement on optical absorption property and charge separation property by Cu-doping process. The charge transfer properties of the solar cells had also been enhanced by the modulation on band energy structure by different Cu-doping concentration. With the relatively larger optical absorption edge, the 0.3 mM Cu–doped ZnO/Sb2S3 quantum dot–sensitized solar cells have exhibited optimal band energy structure for charge transfer, which can obtain higher current density to enhance the photovoltaic power conversion efficiency from 2.55 to 3.14%.