Investigating ASnI2Br wide bandgap tin perovskite for bifacial solar cells: Modeling of bifacial efficiency with comparative analysis

In this study, a novel perovskite bifacial solar cell featuring ASnI₂Br as the absorber material, with the A-site cation represented by EDA_0.01(GA_0.06(FA_0.8Cs_0.2)_0.94)_0.98, was proposed. For the first time, the power conversion efficiency (PCE) of such a structure, achieving a notable 21.94% with rear-side illumination, was obtained. Additionally, the first investigation into three distinct methods for estimating the bifacial efficiency (η_bi) of wide bandgap tin-perovskite bifacial solar cells, namely, characteristics addition (CA), generation addition (GA), and mathematical modeling (MM), was implemented. To validate the efficacy estimated by these methods, we apply them to an additional baseline model calibrated extensively with an experimentally verified bifacial perovskite solar cell (PSC) exposed to concurrent front- and rear illumination. Our findings indicate that the CA and GA methods outperform the MM, with the GA method closely aligning with experimental bifacial PSC parameters. Opting for the superior GA method, our analysis showed that the estimated η_bi of the proposed device is 30.17% under 100 mW cm⁻² front-side and 50 mW cm⁻² rear-side illumination intensity. Furthermore, the η_bi of the proposed device was evaluated under various experimentally calculated rear-side surface spectra, revealing an optimum η_bi of 31.05% when the tile was used as the rear surface material.