Advanced interfacial charge carrier transport enabling the improvement of open-circuit voltage in Sb2Se3 solar cells

Abstract

Effective charge carrier flow is essential for optimizing the optoelectrical properties of antimony selenide (Sb₂Se₃) and achieving highly efficient solar cells. MoSe₂, as an interlayer between Sb₂Se₃ and an Mo back-contact layer, serves as a seed layer for the preferential growth of Sb₂Se₃ nanorod structures, facilitating efficient electron transfer. This study focuses on investigating the altered electrical properties at the surface and interfaces of Sb₂Se₃, highlighting the previously unexplored influence of MoSe₂ on the interfacial carrier transport mechanism. Through the introduction of MoSe₂, a well grown Sb₂Se₃ rod array with a (hk1) orientation was achieved, along with a notable increase in vertical current flow. By exposing the back interface using a dimple-grinder, the direct examination of the interface band alignment revealed the role of MoSe₂ as an electron barrier. These effects led to a 95% improvement in power conversion efficiency (PCE), along with significant enhancements in open-circuit voltage (V_OC) and fill factor (FF), underscoring the importance of optimizing interface contact quality.