Design and optimization analysis of a lead-free perovskite solar cell based on copper (I) iodide hole transport layer

Photovoltaic technology has gained wide acceptance because of its potential to mitigate climate change while offering pathways to reduce carbon footprint and inspiring renewable energy access and uptake. Herein, we investigate the performance of a solar cell configuration, FTO/TiO₂/CH₃NH₃SnI₃/CuI/Pd, by device simulation using solar cell capacitance device simulator (SCAPS-1D). The study analyses the impact of temperature, absorber layer thickness and buffer layers on the electrical and optoelectronic outcomes of the model cell. The simulation reveals optimal power conversion efficiency (PCE) of 23.98%, V_oc of 0.8762, modest fill factor (FF) of 75.27% and remarkable photocurrent density (J_sc) of 34.33 mA/cm². The selection of palladium as the preferred metal back contact is supported by its high work function, stability in ambient conditions, affordability compared to gold and low resistivity. CdS, distinguished by its remarkable PCE of 24.04%, emerges as the most promising buffer material for the model cell. Increased temperature from 260 to 500 K did not affect the electrical parameters significantly indicating that the model cell with CuI as the hole transport layer (HTL) has a robust temperature tolerance and hence stable in the design of perovskite cell modules based on CuI. The optimal density of defects for the material was generally found to be 10¹⁵ cm⁻³ whereas the optimal density for the acceptor was 10¹⁶ cm⁻³. These findings highlight the feasibility of the model cell design, characterized by use of eco-friendly materials, relatively affordable materials, low toxicity, and impressive PCE, thus inspiring potential fabrication and commercialization.