Role of La2CuO4 as Buffer Layer for a Significant Improvement of the Performance of TiO2/Cu2O Based All-Oxide Solar Cell: A SCAPS-1D Numerical Analysis

Currently, low-bandgap Mott-insulating materials are the most promising buffer layers (BLs) for solar power conversion efficiency, unlike organic-halide or lead-containing perovskite materials. They can reduce interfacial recombination by field effect passivation of heterojunctions while maintaining cost-effectiveness and high thermal and electrical stability. Moreover, it is expected to obtain a high quantum efficiency due to multiple carrier generation caused by impact ionization from a single incident photon. This study uses the SCAPS-1D simulator to estimate and improve the efficiency of Cu₂O-based solar cells using Mott insulator La₂CuO₄ (LCO) as a BL in both ideal and non-ideal conditions. The simulations examine how BL thickness, carrier concentration, and defect density affect device performance. Also, different metal contact work functions and working temperatures are examined to improve cell performance. Considering all optimisation parameters in ideal conditions, Au/Cu₂O/TiO₂/Nb: STO solar cell structure without a BL has a PCE of 11.27%, while Au/Cu₂O/LCO/TiO₂/Nb: STO has 28.11%. By incorporating non-idealities, the simulated solar cell can simulate actual conditions. The impact of each non-ideality is studied in detail. These findings suggest that Mott insulating buffer materials have great potential for creating high-efficiency photovoltaic (PV) devices, presenting a new avenue for research.