Preparation of PbLa2(MoO4)4:Er3+/Yb3+ particles via microwave sol-gel route and upconversion photoluminescence properties

PbLa2-x(MoO4)(4):Er3+/Yb3+ phosphors with doping concentrations of Er3+ and Yb3+ (x=Er3+ + Yb3+, Er3+ =0.05, 0.1, 0.2 and Yb3+ = 0.2, 0.45) were successfully synthesized via microwave sol-gel route, and upconversion photoluminescence properties were investigated. Well-crystallized particles, formed after heat-treatment at 900 degrees C for 16 h, showed a fine and homogeneous morphology with particle sizes of 2-5 mu m. Under excitation at 980 nm, PbLa1.7(MoO4)(4):Er0.1Yb0.2 and PbLa1.5(MoO4)(4):Ero(0.05)Yb(0.45) particles exhibited a strong 525 nm emission band, a medium 550 nm emission band in the green region, and a very weak 655 nm emission band in the red region. The Raman spectra of the doped particles indicated the presence of strong peaks at higher and lower frequencies induced by disordered structures of PbLa2-x(MoO4)(4) by the incorporation of the Er3+ and Yb3+ ions into the crystal lattice, which resulted in the unit cell shrinkage accompanying the highly modulated structure with anion deficient MoO4-x group. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.