Features of the Phase Composition and Structure of Eu Doped Y2O3 Submicrospheres

Polycrystalline, non-agglomerated nanopowders based on monosized (Y1-xEux)2O3 submicrospheres were prepared. It was shown that the annealing temperature strongly influences on the structure, mor-phology and composition of the spherical (Y1-xEux)2O3 phosphors obtained. It was found that the concentra-tion quenching effects of Eu3+ luminescence in the (Y1-xEux)2O3 spheres with 70-280 nm diameter is shifted to lower Eu3+ concentrations (x =0,02; 0,05 for 70 and 280 nm spheres respectively) compared with the mi-crocrystalline powders with similar composition (x = 0,09). The reason of this phenomenon probably is for-mation of inhomogeneous phase of (Y1-xEux)2O3 solid solution in the nanopowders with the primary location of bigger Eu3+ ions in the surface area due to active diffusion processes. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3521

Morphology of lead sulfide crystalline particles in size-limited state

Monocrystalline PbS particles of cubic structure ranging in size from 3 to 500 nm, were obtained. Influence of growth conditions on the final particles size and dispersion of lead sulfide nanocrystals, as well as effects of nanocrystals size on their shape have been studied. It was found that increasing of monocrystalline particles size more than 12 nm leads to transition of shape from spherical to cubic, that indicate predominance of surface energy influence on equilibrium geometry of nanocrystals