Crystallographic orientation control and defect passivation for high-efficient antimony selenide thin-film solar cells

Abstract

Antimony selenide (Sb2Se3) is a possible semiconductor material for next-generation solar cells and has reached excellent development in recent years. The (hk1) oriented Sb2Se3 thin films are more beneficial to the transport of carriers than the (hk0) oriented ones. The photovoltaic properties of solar cells are largely determined by the orientation of the absorber layers, thus, controlling thin film orientation is the key method to enhance the photovoltaic performance of Sb2Se3 devices. In this work, the orientations of Sb2Se3 are controlled by the preferred orientation of Mo and selenization temperature. (211) oriented Mo and a selenization temperature of 420 °C are found to facilitate the formation of large (hk1) oriented Sb2Se3 crystal grains. The substrate configuration of glass/Mo/Sb2Se3/CdS/ITO/Ag solar cells were prepared. The (hk1) oriented Sb2Se3 decreases the interfacial and bulk defects within the device, mitigates carrier recombination, and prolongs the carrier lifetime. Thus, the short-circuit current density (JSC) of the solar cell increases from 21.88 to 27.32 mA/cm2 and the champion device has achieved a power conversion efficiency of 7.43%.