Fig. 3
From: Unveiling the operation mechanism of layered perovskite solar cells
Vertical and lateral phase segregation investigation. a Schematic of incident-angle dependent photoluminescence (PL) setup. b The incident-angle-dependent PL spectra of the layered perovskite films illuminated from the front sides (as illustrated in the inset) of the films. c The incident-angle-dependent PL spectra of the layered perovskite films illuminated from the back sides (as illustrated in the inset) of the films. d Absorption spectra of three-dimensional (3D) MAPbI3 thin films and the layered (BA)2(MA)n-1PbnI3n+1 perovskite thin films (n = 1 to 3). e Optical mapping of the layered perovskite (BA)2MA3Pb4I13 films using an optical microscope in transmission mode. Typical bright and dark area are labeled with pink and black squares, respectively. f Absorption spectra measured in the bright and dark area labeled in e. The size of the measured area is 0.6 × 0.6 µm2, smaller than the labeled area
