Microwave sol-gel process of KGd(WO4)2:Ho3+/Yb3 phosphors and their upconversion photoluminescence properties

摘要: Abstract Double tungstate KGd 1− x (WO 4 ) 2 :Ho 3+ /Yb phosphors with doping concentrations of Ho and Yb ( =Ho +Yb , =0.05, 0.1, 0.2 =0.2, 0.45) were successfully synthesized by the microwave sol–gel method, upconversion mechanisms investigated in detail. The particles formed after heat-treatment at 900 °C for 16 h showed a well crystallized morphology particle sizes 2–5 μm. Under excitation 980 nm, UC intensities 0.7 0.1 0.5 0.05 0.45 exhibited yellow emissions based on strong 550-nm emission band green region 655-nm red region, which assigned to 5 S / F → I 8 transitions, respectively. Raman spectra doped indicated presence peaks higher frequencies 764, 812, 904, 984, 1050, 1106, 1250 1340 cm −1 induced disorder [WO ] 2− groups incorporation elements into crystal lattice or new phase formation.