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 (VOC) and fill factor (FF), underscoring the importance of optimizing interface contact quality.