Enhanced Performance of CdTe Solar Cells with Sb2Se3 Back Contacts

Abstract

The barrier at CdTe/metal interface severely limits the efficiency of CdTe photovoltaic devices. Herein, the effectiveness of a thermally evaporated Sb2Se3 buffer layer as a back contact in CdTe solar cells is investigated, revealing a significant enhancement in device performance. Through optimization of Sb2Se3 thickness, a remarkable increase in the open‐circuit voltage (VOC) to 804 mV is achieved, leading to a substantial efficiency improvement of 12.84% when compared to the Au‐only back contact device. X‐ray photoelectron spectroscopy (XPS) reveals a well‐matched energy band alignment at CdTe/Sb2Se3 interface, confirming favorable conditions for hole transport. To further enhance the device performance, Cu doping is implemented in the Sb2Se3 film, resulting in additional improvements to the VOC and fill factor (FF) of the Cu‐doped configuration to 819 mV and 72.35%, respectively, while also enhancing the overall efficiency to 14.3%.