Photovoltaic performance optimization of CBTS based HTL integration in lead free perovskite solar cell: A SCAPS 1D simulation approach

This study investigates the application of Copper Barium Tin Sulfide (CBTS) as HTL (hole transport layer) in FASnI₃-based perovskite solar cells (PSCs). Traditional organic HTLs, such as PEDOT: PSS and Spiro-OMeTAD, exhibit issues including poor thermal stability, susceptibility to degradation, chemical incompatibility, and low intrinsic hole mobility. This study investigates the capability of Cu₂BaSnS₄ (CBTS) as a viable material to mitigate existing limitations, assessing its suitability for enhanced photovoltaic performance and stability. Using the SCAPS-1D simulator, a cell structure of Au/CBTS/FASnI₃/TiO₂/FTO/Al achieved a power conversion efficiency (PCE) of 26.67 %, short-circuit current density (J_SC) of 29.21 mA/cm², with an open-circuit voltage (V_OC) of 1.097 V, and fill factor (FF) of 83.20 %. In this work authors studied the band diagram and impact on PV parameters due to acceptor density, thickness, front and back contact work functions, radiative recombination, and defect density, temperature, electron affinity, Mott-Schottky plot and parasitic resistances. This work highlights the advantages of lead-free PSCs and opens new avenues for their application in advanced solar technologies such as tandem solar cells.