Buchuk R. Electrical and optical properties of Сu6PS5X (X= I, Br) crystals, composites, and solid solutions on their base

The thesis is devoted to the studies of electrical and optical properties of Сu6PS5X (X= I, Br) superionic crystals, composites, and solid solutions on their base. The main features of Raman scattering were studied, the one-mode type of the phonon spectra transformation at Cu Ag cationic substitution was observed. The Urbach behaviour of the optical absorption edge was revealed, the short-wave edge of diffusive reflection spectra was shown to be shifted towards longer wavelengths at Cu Ag substitution. Luminescence and Raman scattering studies in micro-and nanocrystalline Cu6PS5X (X= I, Br) superionic conductors were performed. An essential influence of size effects on the Raman scattering was shown, from the analysis of the vibrational bands lineshape variation the observed changes were concluded to be the manifestation of surface phonon modes. The nanocrystal size reduction was found to lead to a short-wavelength shift of the luminescence bands, their halfwidth variation and a redistribution of their intensities.