Upconversion Properties of NaGd(WO4)2:Ho~(3+)/Yb~(3+) Yellow Phosphors Synthesized by Cyclic Microwave-Modified Sol-Gel Method

摘要

Upconversion properties of the NaGd_(1-x)(WO4)2:Ho~(3+)/Yb~(3+) yellow phosphors with doping concentrations of Ho~(3+) and Yb~(3+) (x = Ho~(3+) + Yb~(3+), Ho~(3+) = 0.05, 0.1, 0.2 and Yb~(3+) = 0.2,0.45) were investigated. The synthesized particles were successfully synthesized by the microwave-modified sol-gel method. Well-crystallized particles showed a fine and homogeneous morphology with particle sizes of 2-5 μm. Under excitation at 980 nm, the upconversion intensity of NaGd_(0.5)(MoO4)4:Ho_(0.05)Yb_(0.45) phosphors exhibited yellow emissions based on a strong 550 nm emission band in the green region and a very strong 655 nm emission band in the red region. The Raman spectra of the particles indicated the presence of Strang peaks at higher frequencies.