Computational Probing of Tin-based Lead-free Perovskite Solar Cells: Effects of Absorber Parameters and Various ETL Materials on Device Performance

Abstract Tin-based perovskite solar cells have gained global research attention due to the lead toxicity and health risk associated with its lead-based analogue. The promising opto-electrical properties of the Tin-based perovskite have attracted researchers to work on developing solar cells with higher efficiencies comparable to Lead-based analogues. Tin-based perovskites outperform the lead-based ones in areas like optimal band gap and carrier mobility. A detailed understanding regarding the effects of each parameters and working conditions on Tin-based perovskite is crucial in order to improve the efficiency. In the present work, we have carried out a numerical simulation of planar heterojunction Tin-based (CH3NH3SnI3) perovskite solar cell employing SCAPS 1D simulator. Device parameters namely thickness of the absorber layer, defect density of the absorber layer, working temperature, series resistance, metal work function have been exclusively investigated. ZnO has been employed as the ETL (Electron transport layer) material in the initial simulation to obtain optimized parameters and attained a maximum efficiency of 19.62 % with 1.1089 V open circuit potential (Voc) at 700 nm thickness (absorber layer). Further, different ETL materials have been introduced into the optimized device architecture and Zn2SnO4 based device delivers an efficiency of 24.3 % with a Voc of 1.1857 V. The obtained results indicate a strong possibility to model and construct better performing perovskite solar cells based on Tin (Sn) with Zn2SnO4 as ETL layer.