Fig. 2. (A and B) UV-vis absorption spectra of 2D mixed (Br : I = 50 : 50) halide perovskite films: (A) 2D RP perovskites with BA and BzA and (B) 2D DJ perovskites with BDA and PDMA. (C–F) 2D photoluminol excitation–emission spectra recorded for 2D perovskite films with varying spacer cations: (C) BA2Pb(Br0.5I0.5)4, (D) BDAPb(Br0.5I0.5)4, (E) BzA2Pb(Br0.5I0.5)4, and (F) PDMAPb(Br0.5I0.5)4, respectively. All films were excited over the 300–440 nm wavelength range, and emissionwas recorded between 450–600 nm.
