Theoretical evaluation on the operation of the high-performance Cu3PSe4-based photonic devices for solar cell and photodetector applications

Abstract Copper selenophosphate has emerged as a highly efficient and sustainable absorber material for thin‑film solar cells and photosensors. In this work, we numerically investigate the performance of a novel n-ZnSe/p-Cu 3 PSe 4 /p + -WSe 2 device structure using the SCAPS‑1D simulator. The design incorporates ZnSe as the window layer and WSe 2 as the back surface field layer, enabling improved carrier transport and enhanced optoelectronic response. A systematic optimization has been carried out by varying layer thicknesses, doping concentrations, and defect densities to achieve superior device characteristics. The optimized structure exhibits an open-circuit voltage of 1.19 V, a short-circuit current density of 31.25 mA/cm 2 , a fill factor of 81.58%, and a power conversion efficiency of 30.36%. As a photosensor, the device demonstrates excellent responsivity of 0.60 A/W and detectivity of 1.68 × 10 18 Jones in the near‑infrared region. These outcomes highlight the potential of Cu 3 PSe 4 -based thin-film devices as promising candidates for next-generation photovoltaic and photonic applications.