Enhanced Performance of CdTe Solar Cells with Sb2Se3 Back Contacts

The barrier at CdTe/metal interface severely limits the efficiency of CdTe photovoltaic devices. Herein, the effectiveness of a thermally evaporated Sb 2 Se 3 buffer layer as a back contact in CdTe solar cells is investigated, revealing a significant enhancement in device performance. Through optimization of Sb 2 Se 3 thickness, a remarkable increase in the open‐circuit voltage ( V OC ) 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/Sb 2 Se 3 interface, confirming favorable conditions for hole transport. To further enhance the device performance, Cu doping is implemented in the Sb 2 Se 3 film, resulting in additional improvements to the V OC 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%.