LAUSR

Abstract Photoluminescence and excitation spectra of stilbene single crystals, polycrystals, and solutions are investigated in the temperature range of 5-280 K. With the increase in the temperature, the photoluminescence bands shift to the short-wavelength region by 600 cm−1, which indicates the existence of Gaussian-distributed localized states. Such states are associated both with different arrangements of the benzene rings with respect to the C = C bond and with different molecule environments in the crystal lattice. The photoluminescence intensity of the polycrystals depends on the grain size and reaches 87% of the single crystal photoluminescence intensity, when the grain size is 2.5 mm.