Fig. 7. Phase modulation of quasi-2D perovskites for effective blue emission.

a Calculated formation energy of PEABr- and IPABr-based perovskites and their mixed quasi-2D perovskites with different n-values. Inset: Atomic model of the PEA/IPA mixed quasi-2D perovskite with n = 3. b UV-vis absorption spectra of the perovskite PEA₂A_1.5Pb_2.5Br_8.5 with different amounts of IPABr additive. c Schematic diagram of the chelating effect on PbBr₂ binding to the surface. d DFT-calculated destabilization energy of PbBr₂ on the quasi-2D perovskite surface when coordinated with GABA and PEA. TA spectra at different timescales for e (PEA)₂Cs₂Pb₃Br₁₀ and f GABA-treated (PEA)₂Cs₂Pb₃Br₁₀ perovskite films. Panels a and b are reprinted from ref. ¹²¹ with permission from Springer Nature. Panels c–f are reprinted from ref. ¹²² with permission from Springer Nature