Venhryn Y. Structure and photoluminescent properties of nanopowder metal oxides in gases.

The work is dedicated to a complex theoretical and experimental study of luminescent, structural and sensory properties of nanomaterials based on ZnO and complex metal oxides. Mathematical modeling of the processes of structure formation and growth morphology in nanoclusters, as well as oxidation of Zn nanoclusters in an oxygen medium and the formation of structures such as "core-shell" using the method of molecular dynamics were performed. The dependences of the structure and shape of the obtained nanoclusters on the initial temperatures of the system, gas concentration and size of Zn nanoclusters are established. Also, the thickness and density of the oxide layer of Zn-ZnO nanoclusters were analyzed depending on the initial system temperatures, gas concentration and size of Zn nanoclusters. The results of experimental studies of structural, photoluminescent and gas - sensory properties of complex nanopowder metal oxides are presented. The peculiarities of the photoluminescent properties of nanopowder metal oxides ZnO, ZnTiO3, Zn2SiO4: Mn, ZnGa2O4, ZnGdO3:Eu, incl. surface-alloyed with various impurities Pt, Si, Ge, in different gaseous media. The main feature of the sensor system we have built is the registration of the photoluminescent glow of the nanopowder metal oxide material adsorbed on it by gas particles. The results of photoluminescent studies made it possible to establish that during the adsorption of gases on nanopowder metal oxides there is a minor shift of the luminosity maxima with a significant change in their intensities. Therefore, it was proposed to register the change not of the intrinsic spectral characteristics of nanopowder materials, but of the colors of their luminescence, which change significantly during the adsorption of gases. Analysis of the nature of color changes of cell of the matrix, when the surrounding atmosphere changes, allows you to analyze the qualitative and quantitative composition of gas components in the environment. The program which allows to recognize gas components by the analysis of character of luminescence of cell of a matrix is created and efficiency of the constructed gas sensor system for recognition and the analysis of gases and their mixes is established.