Figure 3
From: Using pressure to unravel the structure–dynamic-disorder relationship in metal halide perovskites
(a) Raman spectra of MAPbBr\(_3\) measured at different temperatures from 320 to 80 K (steps of 10 K) in the spectral range of the inorganic cage phonon modes using the 785-nm line for excitation. The spectra were normalized to their maximum intensity and shifted vertically for clarity. The different colors of the spectra indicate the changes in phase after every transition. (b) Examples of the performed lineshape fits (green solid curves) to the Raman spectra (black closed symbols) using Gaussian functions for different pressures, as indicated, each one representing a different high-pressure phase of the material. The solid curves in the color of the corresponding phase represent the different phonon components. The shown spectra were obtained by subtracting a special function used for describing the combined effect of the dichroic filter and the broad central peak (see text for details).
