Upconversion Properties of CaGd2(MoO4):Er~(3+)/Yb~(3+) Green Phosphors Synthesized by A Cyclic Microwave-Modified Sol-Gel Method

摘要

Upconversion CaGd2(MoO4)4:Er~(3+)/Yb~(3+) phosphors with doping concentrations of Er~(3+) and Yb~(3+) (Er~(3+) = 0.05,0.1.0.2 and Yb~(3+) = 0.2,0.45) have been successfully synthesized by a cyclic microwave-modified sol-gel method. Well-crystallized particles, formed after heat-treatment at 900 °C for 12 h, showed a fine and homogeneous morphology. Under excitation at 980 nm, CaGd2(MoO4)Er~(3+)/Yb~(3+) particles exhibited strong 525 and 550 nm emission bands in the green region and a weak 655 nm emission band in the red region. The Raman spectra of the particles indicated the presence of strong peaks at both higher frequencies and lower frequencies induced by the disorder of the [MoO4]~(2-) groups with the incorporation of the Er~(3+) and Yb~(3+) elements into the crystal lattice or by a new phase formation.