Fig. 2: DFT calculation and electronic properties of perovskite with or without surface treatment.
a Schematic of bilayer passivation strategy. Differential charge density maps for AlOx on b PbI-terminated perovskite and c FAI-terminated perovskite, where electron depletion is indicated by green and electron accumulation in yellow. Projected density of states (PDOS) from density functional theory calculations for perovskite with different terminations: d FAI-termination; e PbI-termination. The control represents untreated perovskite, while AlOx denotes AlOx-treated perovskite. f Energy-level alignment derived from UPS for control, PDAI2-treated, AlOx-treated, and AlOx/PDAI2-treated perovskite samples. Here, EV refers to the valence band maximum, EC to the conduction band minimum, EF is the Fermi energy level, and EVAC represents the vacuum energy level. g Energy level diagram at the interface between AlOx/PDAI2-treated perovskite and C60. h Band alignment simulated via drift-diffusion modeling for solar cells with AlOx/PDAI2 treatment at the open-circuit condition. Here, Fn and Fp represent electron and hole quasi-Fermi level, respectively. i Simulated energy level profiles and charge carrier densities for AlOx/PDAI2 solar cell at the open-circuit condition.
