fig4

Figure 4. (A) UV-Vis absorption spectra of (BEA)FA₂Sn₃I₁₀ and FASnI₃ perovskite films; (B) TA spectra of (BEA)FA₂Sn₃I₁₀ film at various decay times: distinct bleach peaks at 610 nm (n = 1), 715 nm (n = 2), 780 nm (n = 3). This figure is quoted with permission from Li et al.^[74]; (C) Crystal structures, ESP diagrams, and calculated dipole moments of o-PDA-Sn, m-PDA-Sn, and p-PDA-Sn perovskites (top) and their relative dielectric constant as a function of offset voltage (bottom). This figure is quoted with permission from Yao et al.^[75]; (D) Integrated PL intensity and calculated E_b for 3ABAAc₂ + MABr (left) and 4ABAAc₂ + MABr (right) perovskite films. This figure is quoted with permission from Qian et al.^[76]; E: Schematic band diagrams of carrier transport in EDA-Sn and PDA-Sn/BDA-Sn films. This figure is quoted with permission from Yao et al.^[77]. UV-Vis: ultraviolet-visible; PDA: propanediammonium; TA: transient absorption spectra; PL: photoluminscence.