SiO_2/KGd(WO_4)_2: Eu~(3+) composite luminescent nanoparticles: Synthesis and characterization

摘要

Adsorption of Eu~(3+):KGd(WO_4)_2 (EKGW) on amorphous SiO_2 nanospheres for solid state lighting (SSL) was investigated. SiO_2/KGd(WO_4)_2:Eu~(3+) (SiO_2/EKGW) nanocomposite was successfully synthesised through stober process along with polymeric metal complex sol-gel synthesis method. Fluorescent EKGW adsorbed SiO_2 nanospheres were subjected to thermal, structural, vibrational, morphological and luminescence analyses. Powder XRD patterns confirm the existence of monoclinic EKGW crystalline particles on amorphous silica spheres which sintered at high temperature. The metal citrate and ethylene glycol gel formation was identified from FT-IR analysis. Calcination at different temperature revealed periodic removal of organic components. Raman studies further established the formation of double bridge platform of monoclinic EKGW on silica sphere. FE-SEM micrographs of SiO_2 confirm the mono-dispersed spheres of average size 200 nm. Adsorption of crystalline EKGW particles on the surface of nano silica sphere was clearly observed in the TEM micrographs. From emission analysis, it was observed that EKGW : Eu~(3+) samples showed strong red emission under 395 nm excitation and their respective chromaticity coordinates were very close to standard NTSC values.