Effect of silver nanoparticles on the visible upconversion emission of Er3+/Yb3+ co-doped SbPO4-GeO2 glasses

Rare earth-doped glasses are largely studied for developing new and efficient photonic devices. The influence of localized electric fields from the LSPR of metallic nanoparticles (MNP) on the rare-earth luminescent properties is a matter of study. This work describes the effect of Ag-MNP on the visible-upconversion emission of Er3+/Yb3+-co-doped SbPO4-GeO2 glass. Ag-MNP was obtained with an average size of ∼5 nm and a LSPR absorption band at 520 nm. A significant enhancement of the red emission (∼650 nm) of Er3+ as a function of Ag-MNPs content was observed. It showed silver nanocluster emission through excitation at infrared via energy transfer from Er3+ to the Ag nanoclusters. Photoluminescence spectroscopy revealed that longer heat treatment times increase the red emission and enhance the rapid depopulation of 4F9/2 level, reducing the lifetime by 57% due to the LSPR of Ag-MNPs in the vicinity of the Er3+ and Yb3+.