Fig. 2: Comparison of local structure between crystalline and glassy (S-NEA)2PbBr4.
From: Structural dynamics of melting and glass formation in a two-dimensional hybrid perovskite
a X-ray structure factors S(Q) of crystalline and glassy (S-NEA)2PbBr4 obtained from total scattering experiments. Insets (left): magnified low-Q region, highlighting the Q1 and Q2 features in the crystal, and the Q1* feature in the glass. Inset (right): schematic illustration of interplanar spacings d1 and d2, corresponding to Q1 and Q2 features in the crystal structure, respectively. b Corresponding X-ray pair distribution functions D(r). Peaks I-X are indexed according to interatomic correlations. Inset: schematic of peak assignments for Pb-Br (green), Pb-Pb (orange), and Br-Br (purple) distances. Contributions from atom pairs containing C, N, H are omitted due to their low X-ray form factors. c Experimental high-speed high-field MAS 13C NMR spectra (solid lines) collected at 17.6 T. Simulated spectra (dashed lines) and individual simulation components (grey lines) are vertically offset for clarity. Inset: chemical structure of the organic (S-NEA)+ cation. Two-dimensional 13C{1H} HETCOR spectra obtained with cross-polarization for (d) crystalline and (e) glassy (S-NEA)2PbBr4. In (a–e), data for crystalline (S-NEA)2PbBr4 and ag(S-NEA)2PbBr4 are shown in navy and red, respectively. Source data are provided as a Source Data file.
