Local Structure in Crystalline, Glass and Melt States of a Hybrid Metal Halide Perovskite

The pursuit of structure-property relationships in crystalline metal halide perovskites (MHPs) has yielded an unprecedented combination of advantageous characteristics for wide-ranging optoelectronic applications. While crystalline MHP structures are readily accessible through diffraction-based structure refinements, providing a clear view of associated long-range ordering, the local structures in more recently discovered glassy MHP states remain unexplored. Herein, we utilize a combination of Raman spectroscopy, solid-state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy, in situ X-ray diffraction (XRD) and pair distribution function (PDF) analysis to investigate the coordination environment in crystalline, glass and melt states of the 2D MHP [(S)-(-)-1-(1-naphthyl)ethylammonium]