Lukashuk V. Electronic excitations and luminescence of bismuth and tungstate oxyanions in polycrystalline oxygen compounds

The dissertation work is devoted to the study crystalline chemical properties with optic properties and luminescent characteristics at the different types of excitation and determination of the models of luminescent centers thin films and ceramics based on Bi2O3, Y2O3:Ві and Y3Al5O12:Ві, X2Bi6O11 (X=Pb, Sn) and Bi2WxOy (x=1, 2, 3; y=6, 9, 12). The luminescence in ceramics of ?-Ві2О3, Pb2Bi6O11, Sn2Bi6O11 are caused by radiation processes that occur in structural complexes which contain the bismuth ion in nearest oxygen environment. It was shown that the luminescence of thin films Y2O3:Ві and Y3Al5O12:Ві was stimulated by light from centers of two types which arise to substitution of Y3+ by Bi3+ in nodes of the crystalline lattice of Y2O3:Ві (Y3Al5O12:Ві) with point symmetries C2 and C3i (D2 and C3i).The main bands of emission for compounds Bi2WO6, Bi2W2O9 and Bi2W3O12 are assigned to the emission of the self-trapped Frenkel excitons, and two others bands of emission are concluded to be associated with oxygen vacancies.