Lead-free organic inorganic halide perovskite solar cell with over 30% efficiency

In this study, numerical analysis on an Sn-based planner heterojunction perovskite device structure of Glass/ FTO/ ZnO/ CH₃NH₃SnI₃/ CZTS/ Metal, with CH₃NH₃SnI₃ as an absorber layer, was performed by using the solar cell device simulator SCAPS 1D. As an electron transport layer (ETL) and a hole transport layer (HTL), inorganic materials ZnO and CZTS (kesterite) were used. To optimize the device, the thickness of the absorber, electron, and hole transport layers, defect density, and absorber doping concentrations were varied, and their impact on device performance was evaluated. The effect of temperature and work function of various anode materials were also investigated. The optimum absorber layer thickness was found at 750 nm for the proposed structure. The acceptor concentration with a reduced defect density of the absorber layer enhances device performance significantly. For better performance, a higher work function anode material is required. The optimized solar cell achieved a maximum power conversion efficiency of 30.41% with an open-circuit voltage of 1.03 V, a short circuit current density of 34.31 mA/cm^2, and a Fill Factor 86.39%. The proposed cell structure also possesses an excellent performance under high operating temperature indicating great promise for eco-friendly, low-cost solar energy harvesting.