The up-conversion (UC) luminescence properties of polycrystalline Er3+/Yb3+ co-doped NaGd(MoO4)2 phosphors synthesized by a simple solid-state reaction method were investigated in detail. Under 980 nm excitation, Er3+/Yb3+ co-doped NaGd(MoO4)2 exhibited weak red emissions near 660 and 670 nm, and strong green UC emissions at 530 and 550 nm corresponding to the intra 4f transitions of Er3+ (4F9/2, 2H11/2, 4S3/2)→ Er3+ (4I15/2). The optimum doping concentration of Er3+ and 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 strongly shiny green emission. A possible UC mechanism for Er3+/Yb3+ co-doped NaGd(MoO4)2 depending on the pump power dependence was discussed in detail.
Keywords: Upconversion, NaGd(MoO4)2, Two-photon process, Rare earth ion.