Nanodesigning of SiO2: Eu3+ Particles Obtained by Spray Pyrolysis Method and Their Luminescence Properties
Vukoman Jokanović, Miroslav D. Dramićanin,* and Željka Andrić
Institute of Nuclear Sciences
“Vinča,” P.O. Box 522, 11001 Belgrade, Serbia and Montenegro.
Mechanism of droplet formation and the structuring of SiO2:Eu3+ spheres prepared by the process of ultrasonic spray pyrolysis, using colloidal solution consisting of the 7.5 nm SiO2 nanoparticles and Eu(NO3)3×6H2O as a precursor, is described. The proposed model quantitatively defines each line in the size distribution spectrum. Agreement between theoretically obtained basic structural parameters (size distribution and geometry) and experimentally determined values was found. Electron microscopy of SiO2:Eu3+ powder revealed three-level arrangement of material: nanoparticles, sub-particles and spheres, also in agreement with the theoretical model. Luminescence properties of trivalent europium ions imbedded in such structured system are investigated in addition. Characteristic emissions of 5D0→7FJ transitions of Eu3+ ion were found with a good chromaticity and very good luminescence lifetime of 3.3 ms.
Key words: spray pyrolysis, nanodesigning, silica sol, europium, luminescence