Design and Simulation of CsSnI3-based Lead-free perovskite solar cell with various hole transport materials

To address the challenge of lead toxicity in photovoltaic technologies, lead-free perovskite solar cells based on materials with comparatively lower toxicity than Pb have been extensively investigated. Among them, CsSnI 3 has emerged as a promising absorber material due to its inorganic cation framework and favorable optoelectronic properties. However, its chemical instability and defect-mediated recombination significantly limit the performance of solar energy harvesting. In this theoretical study, SCAPS-1D simulations are employed to systematically explore strategies to improve charge transport and suppress recombination in Pb-free perovskite solar cells, focusing on the thermally stable p-type absorber CsSnI 3 . The objective of this work is to optimize the device performance of a planar CsSnI 3 -based p–n heterojunction through a unified and comparative SCAPS-1D analysis, employing Nb 2 O 5 as the electron transport layer in combination with nine different hole transport materials (HTMs). The optimized device architecture, ITO/Nb 2 O 5 /CsSnI 3 /CuS/Au, achieved through judicious selection of carrier transport layers, delivers a power conversion efficiency (PCE) of 25.98%, with a fill factor (FF) of 78.56%, a short-circuit current density ( J s c ) of 30.89 mA cm −2 , and an open-circuit voltage ( V o c ) of 1.068 V, thereby outperforming other commonly employed HTM-based configurations.