Enhancement of Efficiency and Stability for Tin Halide Perovskite Solar Cells by Using Improved Doping Method

In recent years, tin halide perovskite solar cells (PKSCs) have emerged as a promising alternative to lead-PKSCs. However, due to defects such as Sn4+ and iodide vacancies, their efficiency is lower than lead-PKSCs. To address this issue, various strategies are proposed to improve the quality of perovskite, including copper iodide (CuI) doping. Unfortunately, the conventional solvent composition of DMF:DMSO = 4:1 has limited the solubility of CuI, resulting in inconsistent results and limited efficiency improvements. However, this research proposed a preprocessing method of CuI to decrease the defects and improve the perovskite layer's morphology. As a result, the efficiency of tin-PKSCs with both P-I-N and hole transport layer (HTL) free structures is enhanced, increasing from 9.8% to 13.1% and 9.4% to 10.5%, respectively. Moreover, the doped tin-PKSCs have exhibited better stability, retaining 75% of their initial power conversion efficiency (PCE) after being stored in a glovebox for 102 days.