Nanostructure designed powders of optical active materials MexSiOy obtained by ultrasonic spray pyrolysis

Abstract A new approach to the two-level design and self-assembling of Me x SiO y (Me = Gd, Y and Ca or their mixtures) nano-powders from SiO 2 sols is described. The nanostructure design of various optical active materials based on different compounds of Me x SiO y is discussed. These particles were formed by the combination of hydrothermal synthesis and ultrasound spray pyrolysis. The morphology and structural design of the particles and sub-particles are defined by their synthesis procedure and processing parameters. The mean particle size and size distribution of all the Me x SiO y based compounds were determined by SEM analysis. These results were compared with the particle diameter evaluated from the theoretical model of the breaking-up of capillary waves. For all the synthesized powders, the obtained results indicate the possibility of a rigorous design of the structure of the particles throughout their entire hierarchy.