Efficient defect passivation of Sb2Se3 film by tellurium doping for high performance solar cells

Abstract

Defects in a semiconductor dictate the carrier transport and recombination ability, which are critical factors that influence the power conversion efficiency in solar cells. In this study, we demonstrate that the introduction of tellurium is able to fine tune the atomic ratio of Se/Sb in Sb₂Se₃ thin films, both Se-rich and Sb-rich Sb₂Se₃ are obtained. Using fine-tuned device fabrication and deep level defect spectroscopy for characterization, we experimentally disclose that Se-rich Sb₂Se₃ favors the formation of Se_Sb and V_Sb defects, while Sb-rich films benefit the formation of Sb_Se and V_Se defects. With an appropriate excess of Se in Sb₂Se₃, a net efficiency improvement of 2% is obtained when compared with pristine Sb₂Se₃ based solar cells. Our study provides an effective strategy to manipulate the defect formation in Sb₂Se₃ solar cells and inspires further improvement in the efficiency of Sb₂Se₃ solar cells.