Theoretical Simulation on Enhancing the Thin-Film Copper Zinc Tin Sulfide Solar Cell Performance Using MoS₂, MoOx, and CuI as Efficient Hole Transport Layers

This study investigates, by means of numerical simulation, the potential enhancement of copper zinc tin sulfide (CZTS)-based solar cells through the utilization of various hole transport layers (HTLs), namely, MoOx, CuI, and SnS. Notably, we optimize key cell parameters, such as the CZTS absorber layer thickness, defect density, and acceptor concentration. By integrating these HTLs, we aim to achieve the dual benefits of increased photon energy absorption and reduced recombination rates within the device. Our findings highlight the exceptional performance of MoOx and CuI as HTLs, surpassing SnS by a significant margin. Specifically, MoOx and CuI demonstrate a remarkable power conversion efficiency of 23.73% and an impressive fill factor of 88%. Notably, these results closely approach the theoretical limits proposed by Shockley and Queisser. The proposed strategy, which involves tuning band alignment and optimizing global parameters, holds promise for enhancing the efficiency of CZTS heterojunction-based solar cells, ushering in a more sustainable and efficient era of solar energy conversion.