Effects of gold nanoparticles on the enhancement of upconversion and near-infrared emission in Er3+/Yb3+ co-doped transparent glass–ceramics containing BaF2 nanocrystals

The transparent glass–ceramics SiO2–AlF3–BaF2–TiO2–CaCO3 containing BaF2 nanocrystals were successfully prepared by the conventional melting method. The effect of the AuNPs on the enhancement upconversion and near-infrared emission in Er3+/Yb3+ co-doped transparent glass–ceramics under 980 nm laser diode excitation were investigated. The transmission electron microscopy (TEM) micrograph showed the average diameter size of gold nanoparticles is estimated about 4–6 nm. Compared with the glass–ceramics sample without HAuCl4, the upconversion and near-infrared emissions intensity of SAB glass–ceramics samples with HAuCl4 were significantly increased. Particularly, the red UC emission intensity band centered at 850 nm strongly increased about twenty-fold with the increase of HAuCl4 concentration and reaches its maximum at 1.5 mol%, then decreases due to the self-quenching effect. The possible mechanism responsible for the enhancement of upconversion and near-infrared emission in Er3+/Yb3+ co-doped due to effectiveness of surface plasmon resonance were discussed.