Microwave-Assisted Sol-Gel Preparation of KY(WO4)2:Ho~(3+)/Yb~(3+) Yellow Phosphors and Their Upconversion Photoluminescence Properties

摘要

Double tungstate KY_(1-x)(WO4)2:Ho~(3+)/Yb~(3+) yellow phosphors with doping concentrations of Ho~(5+) and Yb~(3+) (x = Ho~(3+) + Yb~(3+), Ho~(3+) = 0.05, 0.1. 0.2 and Yb~(3+) = 0.2. 0.45) were successfully prepared by the microwave-assisted sol-gel method and their upconversion photoluminescence properties was investigated. Well-crystallized particles, formed after heat-treatment at 900 °C for 16 h, showed a fine and homogeneous morphology with particle sizes of 2-5 μm. Under excitation at 980 nm, the upconversion intensity of KY_(0.5)(MoO4)4:Ho_(0.05)Yb_(0.45) phosphor exhibited yellow emissions based on a strong 550 nm emission band in the green region and a strong 655 nm emission band in the red region. The Raman spectra of the particles indicated the presence of strong peaks at higher frequencies and a weak peak at lower frequency induced by the disorder of the [WO4]~(2-) groups with the incorporation of the Ho~(3+) and Yb~(3+) elements into the crystal lattice or by a new phase formation.