Investigation of FABr treatment's potential for triple-cation multi-halide perovskite solar cells

In order to preserve the effectual potential of triple-cation coupled with multi-halide perovskites (PVTs), the phase-related conflict amongst different precursors has to be resolved. There arises the necessity of post-growth passivation treatments, especially using formamidinium bromide (FABr) upon such PVT films. In this research, a methodical comparison assessment is performed on triple-cation, multi-halide (CsFAMAPbIBr)-based PVT solar cells (PSCs) with and without FABr passivation using numerical study. A meticulous estimation of all the performance parameters of both PSCs was implemented in accordance with transformations in thickness, effective density, and acceptor density of the PVT absorber layer together with the charge transport layer thickness variations. The investigation revealed that the charge carrier generation rate remained the same after FABr passivation, however, the recombination rate was lowered by ∼ 32 % (from 7.27 × 10²¹ to 4.92 × 10²¹ cm^-3s⁻¹). The analysis discerned that at minimum valence band effective density of PVT absorber: 1 × 10¹⁷ cm⁻³, FABr-treated CsFAMAPbIBr-based PSC ensures the highest power conversion efficiency of 24.62 % against its un-passivated correspondent of 22.25 %. Further, this investigation imparts the remarkableness of FABr passivation treatment in regulating the overall performance of triple-cation and multi-halide-based PSCs.