Numerical investigation of high-performance bilayer tin-based perovskite solar cells with SCAPS-1D

Abstract

A comprehensive simulation-based investigation was conducted on an advanced, lead-free perovskite solar cell (PSC) design. This cell achieved high performance through its novel absorber architecture, which utilized a dual-layer configuration made of tin-based perovskite materials (CsSnI₃ and CsSnCl₃). Simulations were carried out to determine device performance and stability limits by employing the SCAPS-1D software tool. The device structure was designed to enable bandgap alignment with CsSnI₃, which was used as a narrow bandgap material to act as a light harvester, and CsSnCl₃, which was used as a wider bandgap material to act as a charge and defect passivation layer. Prior to the simulations, necessary material parameter details, such as the orbital components forming the band edges and bandgap widening, were thoroughly verified. RIGOROUS simulations on SCAPS-1D revealed a maximum power conversion efficiency (PCE) value of 30.02% (FF = 88.56%, J_sc = 32.09 mA cm⁻², and V_oc = 1.05 V) when optimal parameter inputs were used. Important stability constraints on various PSC devices were obtained by precisely modelling the defects, which resulted in PCE failure when either the interface defect density value and/or the respective bulk density value of either CsSnI₃/CsSnCl₃ layer exceeded 1 × 10¹⁵ cm⁻³. Therefore, high-quality materials are mandatory. In addition, thermal stability analysis indicated that the PCE value is inversely related to temperature. Importantly, the analysis indicates that the voltage component V_oc influences the PCE value predominantly.