New Nanostructure NiO–GeSe Core–Shell/MAPbBr3 Solar Cell in Solar Photoelectrochemical Water Splitting: Superior Efficiency Enhancement

Solar-driven photoelectrochemical (PEC) water-splitting cells coupled with a photovoltaic (PV) cell as a photoanode have become an intriguing topic in solar energy conversion. In this study, for the purpose of developing a system with high efficiency, several photoanode materials were investigated to adjust the oxygen evolution reaction and the hydrogen evolution reaction (HER) energy bands. Among all, MAPbBr₃ with a wide bandgap (2.3 eV) was selected. However, the power conversion efficiency of the PV cell was not desirable due to the low light absorption. Therefore, the NiO–GeSe core–shell was placed inside the perovskite layer to enhance light absorption and carrier generation. In order to achieve a cell with the maximum performance, the core–shell height, and the shell radius were optimized, where the optimum structure was recognized with a core–shell height of 300 nm and a radius of 25–60 nm. The system’s total efficiency, which is represented by the solar to hydrogen efficiency, was then increased from 5.49% to 19.74% for the planar and nanostructure photoanode, respectively. The proposed PEC cell with the optimized photoanode is considered as the most efficient half-tandem and perovskite-based reported coupled system, operating without the need for an external voltage. In this study, three optical, electrical, and electrochemical models were solved using the finite element method to analyze the coupled system.