Upconversion multicolor tuning of NaY(WO4)2:Tb3+ with Eu3+ doping

A series of Tband Euco-doped NaY(WO)phosphors were synthesized by hydrothermal reactions.The crystal structure,morphology,upconversion luminescent properties,the energy transfer from Tbto Euions and the ~5 D→ ~7 Ftransition of the Tbion in NaY(WO):Tb,Euphosphors were investigated in details.The results indicate that all the synthesized samples are of pure tetragonal phase NaY(WO)2.Furthermore,the micrometer-sized needle spheres and excellent dispersion of the particles are obtained by adding polyethylene glycol(PEG-2000) as the surfactant.Phosphors of NaY(WO):Tb,Euexhibit the492 nm blue emission peak,546 nm green emission peak,595 nm orange emission peak and 616 nm red emission peak under 790 nm excitation.The energy transfer from Tbto Euis a resonant transfer,in which electric dipole-dipole interaction plays a leading role.By adjusting the doping concentration of Euin NaY(WO): 1.0 mol%Tb,xmol%Euphosphors,the emitting color of UC phosphors can be tuned from green to red.