Optimization and Performance Analysis of Inorganic Lead-Free CsSnBr3 Perovskite Solar Cells Using Diverse Electron Transport Materials

The rapid enhancement in the power conversion efficiency of perovskite solar cells (PSCs) within a short time frame has introduced challenges related to the instability and toxicity linked with lead (Pb), impeding their progress toward commercial viability. In response, the exploration of Pb-free alternatives, such as CsSnBr3, has garnered substantial research attention. CsSnBr3 stands out as a highly promising contender for fulfilling the role of an absorber layer in solar cell technology, distinguished by its economical nature, robust stability, and impressive efficiency. In this study, CsSnBr3 is employed as an absorber layer, Cu2O as the hole transport layer (HTL), and TiO2, PCBM, WS2, ZnO, SnO2, and IGZO as electron transport layers (ETLs). This work focuses on enhancing the photovoltaic (PV) performance parameters of CsSnBr3-based PSCs using SCAPS-1D numerical simulation. This is achieved by optimizing characteristics (thickness, doping, and defect density) of the light absorber layer, ETLs, and HTL. Additionally, the effects of doping and defect density (Nt) on the PV performance at CsSnBr3/ETL and HTL/CsSnBr3 interfaces are investigated. The device architecture’s performance was significantly influenced by the absorber layer’s thickness, acceptor density, defect density, and the combination of various ETLs and HTLs. Optimized devices employing TiO2, PCBM, WS2, ZnO, SnO2, and IGZO ETLs exhibited PCEs of 21.64, 21.94, 22.43, 21.94, 21.94, and 21.88%, respectively. Moreover, the study included the illustration of capacitance effects and Mott–Schottky (M–S) analysis for the six optimized devices, complemented by the computation of corresponding J–V and QE characteristics. The PV performance obtained from this thorough analysis is then compared with previously published theoretical and experimental results for CsSnBr3-based PSCs. The performance of the top six devices is validated and compared using the wxAMPS simulation tool. By employing a variety of analytical techniques and theoretical simulations, an optimized configuration is developed, leading to the achievement of the highest reported efficiency to date at 22.43% using any simulation method for indium-doped tin oxide/TiO2/CsSnBr3/Cu2O/Au configuration.