<p>This work investigates the photovoltaic performance of a p-CuO/n-Si solar cell using the solar cell capacitance simulator-one dimension (SCAPS-1D) software. The input parameters for the simulation, including the band gap energy and absorption coefficient, were experimentally determined for the CuO absorber layer synthesized via the dip-coating method. The presence of the polycrystalline CuO phase was confirmed through comprehensive structural and analytical characterization. The CuO layer exhibited an optical band gap energy of 1.5 eV and a high optical absorption coefficient of ~8 × 10⁴cm⁻¹, demonstrating its suitability for high-efficiency solar cell applications. Simulations of the p-CuO/n-Si heterojunction solar cell revealed an open-circuit voltage of 789 mV, a short-circuit current density of 27.9 mA/cm², a fill factor of 58%, and an overall power conversion efficiency of 12.98%, outperforming previously reported values in the literature. Furthermore, the effect of the CuO layer’s thickness and band gap energy on solar cell’s key performance metrics was systematically analyzed. The results indicate that optimizing the CuO layer thickness within the range of 0.2–0.5 µm and tailoring the band gap energy within 1.3–1.7 eV range can significantly enhance the solar cell’s photovoltaic performance.</p> Graphical Abstract <p></p>