Applicability of La-Doped BaSnO ₃ as an Efficient ETL for Perovskite Solar Cells

Perovskite solar cells (PSCs) have been reported to have a power conversion efficiency (PCE) of 27.3%, although their instability in enduring moisture, heat, and light is a major hindrance in energy-related applications. In this work, we investigate the role of La-doped BaSnO3 (LBSO) as an electron transport layer (ETL) to improve the aging performance of PSCs and its suitability with a fixed hole transport layer (HTL) and various absorber layers for PSCs. The first-principles calculations are performed on pristine BaSnO3 and LBSO using the full potential linear augmented plane wave (FPLAPW) method within a time-efficient orbital-independent modified Becke–Jhonson (mBJ) approach. The calculated results indicate that La doping results in BaSnO3 being an n-type semiconductor with electronic properties appropriate for its application as an efficient ETL for PSCs. The optical absorption and reflectivity spectra govern the superiority of LBSO over BaSnO3, and LBSO is found to transmit the solar photons in the perovskite absorber layer in a better way. The numerical simulations also authenticate LBSO as a more suitable ETL than BaSnO3 in the PSCs having prominent absorber layers, including MAPbI3, FAPbI3, CsPbI3, CsxFA1–xPbI3, and MAPb(I1–xClx)3, where MA = CH3NH3+ and FA = CH(NH2)2+, combined with the PTAA HTL.