Numerical modeling and optical optimization of CuSe-based heterojunction solar cells: a path toward 27.7% efficiency

This study presents a comprehensive numerical simulation and optoelectronic optimization of copper selenide (CuSe)-based heterojunction solar cells using the solar cell capacitance simulator in a one-dimensional SCAPS-1D framework. I provide a detailed investigation into the optical properties, including quantum efficiency (QE) and photon absorption, alongside charge transport and recombination dynamics. A Back Contact/CuSe/CdS/ZnO/ITO structure is examined to clarify the influence of absorber thickness, defect density, and carrier collection on device performance. Simulation results demonstrate that optimizing the absorber thickness to 5 µm enhances optical absorption, increasing the short-circuit current density (Jsc) to 31.32 mA/cm 2 and improving the quantum efficiency across the visible spectrum. By strategically suppressing Shockley-Read-Hall (SRH) recombination and engineering the back contact work function (>5.6 eV), I achieve a maximum theoretical power conversion efficiency (PCE) of 27.7% (Voc: 1.017 V, FF: 86.93%). Furthermore, I analyze the impact of operating temperature (275–400 K) on device stability, revealing the importance of thermal management. These computational insights offer a strategic roadmap for developing high-performance CuSe photovoltaics, emphasizing the role of optical and interface engineering in moving toward the Shockley-Queisser limit.