Device modelling and optimization of new lead-free (NH₄)₃Sb₂I₉ perovskite solar cells by using SCAPS-1D software

Abstract Advancing lead-free perovskite solar cells (PCSs) is essential for developing sustainable and eco-friendly solar technologies. These alternatives to lead-based PSCs offer notable benefits, including low-cost, excellent stability, and promising efficiency, positioning them as attractive candidates for next-generation photovoltaic applications. Among the emerging materials, (NH 4 ) 3 Sb 2 I 9 stands out due to its favourable optoelectronic properties and environmental safety. This study investigates the impact of different HTLs and ETLs on the performance of (NH 4 ) 3 Sb 2 I 9 -based devices using SCAPS-1D software. Several parameters influencing device efficiency were optimized, including thickness of absorber layer, operating temperature, work function of back contact, donor density, defect density (N t ), series and shunt resistance. The optimized device structure, FTO/WS 2 /(NH 4 ) 3 Sb 2 I 9 /MASnBr 3 /Au achieved a PCE of 20.08% with a V OC of 1.65 V, J SC of 13.83 mA cm −2 and FF of 87.93% at 300 K and N t of 10 13 cm −3 . These results demonstrate the strong potential of antimony-based perovskites in the development of high-performance, lead-free solar cells.