Effect of Copper nanoparticles on the enhancement of upconversion in the Tb3+/Yb3+ co-doped transparent glass-ceramics

The transparent glass-ceramics SiO2-AlF3-BaF2-TiO2-CaCO3 containing BaF2 nanocrystals were successfully prepared by conventional melting method. The effect of CuNPs on the enhancement upconversion emission intensity in the Tb3+/Yb3+ co-doped transparent glass-ceramics under 980 nm laser diode excitation were investigated. The structural investigation carried out by X-ray diffraction (XRD) and transmission electron microscopy (TEM) evidenced the formation of cubic BaF2 nanocrystals. The distribution of Copper nanoparticles and the average diameter size which were confirmed by the results of XRD, TEM measurements. Compared with the glass-ceramics sample without Cu2O element, the intensity of upconversion emission was significantly increased. Particularly, the red UC emission intensity bands at 588 and 624 nm strongly increased with the increase of Cu2O concentration and reached its maximum at 2.5 mol.%, then decreases due to the self-quenching effect. The possible mechanism responsible for the enhancement of upconversion emission intensity in the Tb3+/Yb3+ co-doped due to effectiveness of surface plasmon resonance was discussed. (C) 2014 Elsevier B.V. All rights reserved.