9-13 July 2012
Energy transfer from Ce3+ to Tb3+ in low quartz and amorphous SiO2 hosts
Presented by Mr. Kamohelo George TSHABALALA on 12 Jul 2012 from 17:30 to 19:30
Type: Poster Presentation
Session: Poster Session
Track: Track A - Division for Condensed Matter Physics and Materials
Low quartz and amorphous Ce<sup>3+</sup>-Tb<sup>3+</sup> co-activated SiO<sub>2</sub> phosphors were synthesized by a solution combustion using urea as a fuel. The objective of this study was to compare the efficiency of energy transfer form Ce<sup>3+</sup> to Tb<sup>3+</sup> in low quartz and amorphous SiO<sub>2</sub> hosts. The phosphors were annealed in a reducing atmosphere of 4%H2/96% Ar mixture at an elevated temperature of 1000 °C for 2 hours. This was meant to reduce incidental presence of Ce<sup>4+</sup> (non-luminescent) to a fully homogeneous distribution of Ce<sup>3+</sup> ions in silica matrix. As confirmed by X-ray diffraction (XRD) data, SiO<sub>2</sub> was produced as either low quartz or amorphous phase. The photoluminescence (PL) data showed that green emission of Tb<sup>3+</sup> at 543 nm was sensitized by Ce<sup>3+</sup>, i.e. there was energy transfer from Ce<sup>3+</sup> to Tb<sup>3+</sup> resulting in an improvement of the green line emission due to the 5D4→7F5 transitions of Tb<sup>3+</sup> ions. Possible mechanism of UV down-converted green emission due to energy transfer from Ce<sup>3+</sup> to Tb<sup>3+</sup> is discussed.
Prof O.M. Ntwaeaborwa, email@example.com, University of the Free State