Impact of Hole Transport Layers in Inorganic Lead-Free B-γ-CsSnI3 Perovskite Solar Cells: A Numerical Analysis

Abstract

Tin-based halide perovskite compounds have attracted enormous interest as effective replacements for the conventional lead halide perovskite solar cells (PCSs). However, achieving high efficiency for tin-based perovskite solar cells is still challenging. Herein, we introduced copper sulfide (CuS) as a hole transport material (HTM) in lead free tin-based B-γ-CsSnI3 PSCs to enhance the photovoltaic (PV) performances. The lead free tin-based CsSnI3 perovskite solar cell structure consisting of CuS/CsSnI3/TiO2/ITO was modeled and the output characteristics were investigated by using the one dimensional solar cell capacitance simulator (SCAPS-1D). The CuS hole transport layer (HTL) with proper band arrangement may notably minimize the recombination of the charge carrier at the back side of the perovskite absorber. Density functional theory (DFT)-extracted physical parameters including the band gap and absorption spectrum of CuS were used in the SCAPS-1D program to analyze the characteristics of the proposed PV device. The PV performance parameters of the proposed device were numerically evaluated by varying the absorber thickness and doping concentration. In this work, the variation of the functional temperature on the cell outputs was also studied. Furthermore, different HTMs were employed to investigate the PV characteristics of the proposed CsSnI3 PSC. The power conversion efficiency (PCE) of ~29% was achieved with open circuit voltage (Voc) of 0.99 V, a fill factor of ~87%, and short circuit current density (Jsc) of 33.5 mA/cm2 for the optimized device. This work addressed guidelines and introduced a convenient approach to design and fabricate highly efficient, inexpensive, and stable lead free tin-based perovskite solar cells.