On the arrangement of pyridinium cations in one-dimensional PyPbBr3 perovskite-related compound: DFT calculations and...

Solving the problem of the arrangement of pyridinium cations in one-dimensional PyPbBr3 perovskite-related compound, the possible configurations with different orientation of the pyridinium cations relative to the anionic framework were theoretically proposed. Their structural characteristics and formation energy values were estimated using density functional theory (DFT) calculations. The calculated and experimental Raman spectra were compared in the wide spectral range, and the correspondence between the observed spectral lines and the characteristic modes in the calculated vibrational spectra of the PyPbBr3 models was established. The presence of several orientations of Py cations in the PyPbBr3 sample at room temperature was suggested.