Upconversion luminescence from poly-crystalline Yb3+, Er3+ co-doped NaGd(MoO4)(2) by simple solid state method

Up-conversion (UC) luminescence properties of polycrystalline Er3+/Yb3+ doped NaGd(MoO4)(2) phosphors synthesized by a simple solid-state reaction method were investigated in detail. Used to 980 nm excitation (InfraRed area), Er3+/Yb3+ co-doped NaGd(MoO4)(2) exhibited very weak red emissions near 650 and 670 nm, and very strong green UC emissions at 540 and 550 nm corresponding to the infra 4f transitions of Er3+ (F-4(9/2), H-2(11/2), S-4(3/2))-> Er3+ (I-4(15/2)). The optimum doping concentration of Er3+, Yb3+ for highest emission intensity was determined by XRD and PL analysis. The Er3+/Yb3+ (10.0/10.0 mol%) co-doped NaGd(MoO4)(2) phosphor sample exhibited very strong shiny green emission. A possible UC mechanism for Er3+/Yb3+ co-doped NaGd(MoO4)(2) depending on the pump power dependence was discussed.