Fullerene-C60 and PCBM as interlayers in regular and inverted lead-free PSCs using CH3NH3SnI3: an analysis of device performance and defect density dependence by SCAPS-1D.

Abstract

One of the challenges hindering the commercialization of perovskite solar cells (PSCs) is the presence of toxic metals such as lead in their composition. Simulation studies using SCAPS-1D have already been conducted on lead-free PSCs to find optimized solar cell parameters, having tin as the primary candidate for replacing lead in perovskites. Here, we used fullerene-C60 and its derivative PCBM as interlayers in a lead-free tin-based PSC between the ETL (ZnO) and the perovskite MASI in both regular and inverted configurations of PSCs using SCAPS-1D software. To the best of our knowledge, this is the first simulation study reporting the impact of using fullerene-C60 and PCBM as interlayers in lead-free PSCs. The defect density (Nt) of the perovskite material is varied, allowing us to observe its influence on the power conversion efficiency (PCE). Using an Nt value of 1017 cm-3 without the interlayer, the PCE was 6.90% and 3.72% for regular and inverted devices. Using PCBM as an interlayer improves the efficiency of both simulated PSCs, achieving a maximum PCE of 8.11% and 5.26% for the regular and inverted configurations, respectively. Decreasing the Nt from 1017 cm-3 to 1016 cm-3 caused a significant increase in efficiency, reaching 13.38% (n-i-p) and 10.00% (p-i-n). Finally, using the optimized parameters and an ideal Nt value (1013 cm-3), both PSCs achieved a PCE close to 30%.