Synthesis process and the luminescence properties of rare earth doped NaLa(WO4)2 nanoparticles

Rare earth doped NaLa(WO4)2 nanoparticles have been prepared by a simply hydrothermal synthesis procedure. The X-ray diffraction (XRD) pattern shows that the Eu3+-doped NaLa(WO4)2 nanoparticles with an average size of 10–30 nm can be obtained via hydrothermal treatment for different time at 180 °C. The luminescence intensity of Eu3+-doped NaLa(WO4)2 nanoparticles depended on the size of the nanoparticles. The bright upconversion luminescence of the 2 mol% Er3+ and 20 mol% Yb3+ codoped NaLa(WO4)2 nanoparticles under 980 nm excitation could also be observed. The Yb3+–Er3+ codoped NaLa(WO4)2 nanoparticles prepared by the hydrothermal treatment at 180 °C and then heated at 600 °C shows a 20 times stronger upconversion luminescence than those prepared by hydrothermal treatment at 180 °C or by hydrothermal treatment at 180 °C and then heated at 400 °C.