Enhancing Photovoltaic Performance of Bi-Doped Perovskite Solar Cells with Novel Double Electron Transport Layer: Achieving High Open-Circuit Voltage and Efficiency

Abstract

Perovskite solar cells using pristine and 6% Bi-doped MAPbI₂Br perovskite layers are deposited using a spin coating route. XRD analysis reveals that the structure of MAPbI₂Br is cubic and the grown films are integrating large grains with low micro-strain. UV-visible spectra of the MAPbI₂Br perovskite solar cell and the 6% Bi-doped MAPbI₂Br perovskite solar cell show a narrower bandgap (E_g) and higher refractive index. The characteristics of the ETL directly affect the photovoltaic performance of Bi-MAPbI₂Br perovskite material. The present report aims to propose a new double electron transport layer composed of TiO₂ and Al-SnO₂ for MAPbI₂Br-based PSCs. In the experimental approach, we reached a high open circuit voltage value of 1.07V, while achieving remarkable power conversion efficiencies of 10.39 %. Notably, this is consistent with the highest V_oc achieved so far for Bi-MAPbI₂Br-based PSCs with an inorganic electron transport layer (Al-SnO₂). The results from this study underscore the importance of the conduction band alignment of MAPbI₂Br with the conduction band of Al-SnO₂ to enhance electron flow and minimize recombination. This alignment leads to increased V_oc and total PCE for PSCs.