Fig. 2: Evolution of MAPbBr3 crystal structure with vacuum exposure.
a, b Schematics of the XRD measurement configuration and procedure; c XRD of the powder obtained from grinding, before and after vacuum exposure for 5 h and 22 h under pressure of 1 × 10−6 mbar, in comparison with the standard cubic phase. d Magnified XRD of (200), (110), and (210) diffraction peaks with a two-branch feature shown by the dashed lines, in which two branches correspond to the structure of expanded lattice at surface and interior lattice respectively. The lower angle branch dominates at 0 h and 22 h, while the higher angle branch takes over at 5 h. The higher angle branch is accompanied by a shoulder at 5 h, as labelled by the black arrows. Source data are provided as a Source Data file.
