Authors: D. Tatar, H. Kaygusuz, F. Tezcan, B. Erim, M.L. Ovecoglu, G. Ozen
Affilation: Istanbul Technical University, Turkey
Pages: 959 - 961
Keywords: Y2O3 nano-powders, absorption, Raman scattering, Structure, Thermal properties
The chemical decomposition technique was used to sythesize Y2O3 nanophospors. This technique (to our knowledge, a new technique used to synthesize Y2O3 nanocrystalline phosphors) is based on the thermal decomposition of Yttrium alginate gels. The gels were produced in the form of beads by ionic gelation between a yttrium solution and sodium alginate. The wet beads were annealed at 600, 800 and 1000 °C for various annealing times. The TGA technique was used to obtain some information about the thermal properties of the products as function of annealing temperature and the duration of the annealing process. The TG/DTG scans show that the powder undergoes three different phase transitions in different temperature ranges. Infrared absorption (FTIR) and the Raman scattering (RS) measurements were carried out for the investigation of the optical properties. The stretching frequency of Y-O absorption was determined to occur below 700cm-1 from the FTIR scans. Both the peak intensity and the half-width at half absorption intensity increase with the crystalline size The measurements show that the peak intensity and the half-width at half maximum of IR-absorption and the Raman peak intensities increase while the Raman peak frequencies shift to higher frequencies as the crystalline size of the powder varies from 9nm to 200nm with annealing temperature.