fig2
Figure 2. Photoresponse properties of as-prepared perovskite films. (A) UV-Vis absorption spectra (in which Stage-x represents x layers of [PbI5Br]4- octahedra sandwiched between each two 3-TFMBA molecular planes), (B) corresponding (Ahν)2vs.hν curves, (C) steady PL spectra and (D) TRPL spectra of (3-TFMBA)2(Cs0.17FA0.83)n-1Pbn(I0.83Br0.17)3n-1I2 perovskite films.