Luminescence Behaviors of the New Upconversion Phosphors of Yb/Ho Co-Doped (Gd1-xLux)3Al5O12 (x=0.1-0.5) Garnet Solid Solutions

Abstract

The metastable garnet lattice of Gd3Al5O12 (GdAG) was effectively stabilized via doping with significantly smaller Lu3+, and based on which (Gd,Lu)AG:Yb/Ho was developed in this work as a new type of upconversion phosphor. The phosphor particles calcined from the precursors synthesized via carbonate precipitation were observed to have good dispersion and fairly uniform morphologies. Optical spectroscopy found that the [(Gd1-xLux)0.948Yb0.05Ho0.002]3Al5O12 (x=0.1-0.5) garnet powders exhibit a green emission centered at ~543 nm (the 5F4,5S25I8 transition of Ho3+) and a red emission centered at ~668 nm (the 5F55I8 transition of Ho3+) under laser excitation at 978 nm. The upconversion emission intensity was found to decrease with increasing Lu3+ doping. Meanwhile, the dependence of up-conversion emission intensity on the pumping power was measured and the up-conversion mechanism was discussed in detail. The Yb/Ho codoped (Gd,Lu)AG garnet system developed herein may potentially be used as a new type of luminescent material.