Ultrafast carrier kinetics at surface and interface of Sb2Se3 film by transient reflectance

Antimony selenide (Sb2Se3) is a promising low-cost and environmentally-friendly semiconductor photovoltaic material. The power conversion efficiency of Sb2Se3 solar cells has been improved to 10% in the past few years. The carrier recombination transfer dynamics is significant factor that affects the efficiency ofSb2Se3 solar cells. In this work, carrier recombination on the Sb2Se3 surface and carrier transfer dynamics at the CdS/Sb2Se3 heterojunction interface are systematically investigated by surface transient reflectance. According to the evolution of relative reflectance change , the carrier thermalization and band gap renormalizationtime of Sb2Se3 are determined to be in a range from 0.2 to 0.5 ps, and carrier cooling time is estimated to beabout 3-4 ps. Our results also demonstrate that both free electron and shallow-trapped electron transfer occurat the Sb2Se3/CdS interface after photo excitation. Our results present a method of explaining the transient reflectance of Sb2Se3 and enhancing the understanding of carrier kinetics at Sb2Se3 surface and Sb2Se3/CdS interface

Automated summary

Antimony selenide (Sb2Se3) is a promising low-cost and environmentally-friendly semiconductor photovoltaic material. This study investigates the carrier recombination and transfer dynamics of Sb2Se3, revealing the carrier thermalization, band gap renormalization, and carrier cooling time. It also uncovers the transfer of both free electron and shallow-trapped electron at the CdS/Sb2Se3 interface.