Dual Light Harvester in Perovskite Solar Cell Delivering PCE of 25.86 %

This work deals with numerical analysis of a dual light harvester perovskite material based solar cell which is an alternative to all-perovskite tandem solar cell. The standalone $\mathbf{I T O} / {\mathbf{T i O}_{\mathbf{2}}} / {\mathbf{C s S n I}_{\mathbf{3}}} \mathbf{/ N i O} / \mathbf{A u} $ (S1) ITO/BaSnO3/Cs0.15MA0.15 $\mathrm{FA}_{0.70} \mathrm{~Pb}\left(\mathrm{I}_{0.85} \mathrm{Br}_{0.15}\right)_{3} / \mathrm{NiO} / \mathrm{Au}$ (S2) and ITO/BaSnO3${ }_{3}$ Cs0.15MA0.15FA0.70Pb(I0.85Br0.15)3/CsSnI3/PEDOT:PSS/Au (S3) are modelled in SCAPS 1D and comparatively analyzed aiming the best performance. The S3 delivered a maximum power conversion efficiency of 25.86% which is attributed to high photogeneration and low recombination and is followed by S1 and S2 which delivers 23.27 % and 20.52 % respectively. The S3 is more prone to the impact of bulk defect density compared to others. The S1 and S2 are less vulnerable to interface defect densities compared to $\mathbf{S 3}$. The results of this work may provide a pathway to the development of multi absorber-based tandem device with minimal deposition steps.