Preparation and photoluminescence properties of SrY 2O 4:Yb 3+, Er 3+ powders

Abstract

Yb 3+/Er 3+ co-doped SrY 2O 4 powders are prepared by developing a nitric-decomposition method. Under 980 nm laser excitation, the green and red up-conversion emissions are observed at around 549 and 661 nm, which are attributed to the transitions of 4S 3/2 → 4I 15/2 and 4F 9/2 → 4I 15/2 of Er 3+ ions, respectively. The intensity ratio of the red emission to the green one increases with Yb 3+ doping concentration. A quadratic dependence of the two emissions on excitation power is obtained, indicating that a two-photon process populates the 4S 3/2 and 4F 9/2 levels for the SrY 2O 4 powders. Especially, it is found that at lower excitation power, Yb 3+ doping concentration has an important influence on the slopes of the emission intensity versus excitation power, similar with the excitation power. The results can be helpful for the design and applications of low-cost near-infrared laser diodes.