Efficient ACZTS solar cells using optimized ZnO/metal/ZnO buffer multilayer: A combined FDTD-PSO approach

Abstract

Kesterite solar cells have been identified as promising candidates for high-efficiency and environmentally sustainable thin-film photovoltaic applications. These devices exhibit tunable bandgap and good optical absorption properties. However, improvements in regarding light absorption, open-circuit deficit and short-circuit current are urgently required to overcome the efficiency limitations. The present investigation aims at developing a new design framework based on combining FDTD-PSO (Particle Swarm Optimization) numerical simulations, in order to improve the photovoltaic performance of the thin-film CZTS solar cells. To do so, comprehensive numerical analysis based on FDTD technique are carried out to study the photovoltaic properties of the solar cell including the impact of various metallic layers (MLs) such as gold, silver and copper inserted in the ZnO buffer layer and its geometry on the device performance. In addition, PSO method is used to identify the best metal choice in ZnO/metal/ZnO buffer and the associated best geometry allowing the highest efficiency of ACZTSSe solar cell. It is found that the insertion of metallic layer in the ZnO film leads to induce enhanced light management, which resulted in improved photovoltaic performances of ACZTSSe solar cell. The optimized structure shows a high power conversion efficiency of 15.8 %, improved short circuit current of 35.7 mA/cm² and a superior fill factor of 74 %. The recorded photovoltaic performances demonstrate the potential of the adopted design strategy for developing efficient thin-film solar cells, which can provide new paths and promising approach to improve the emerging photovoltaic systems based on thin-film technology.