Uniform Ln{sup 3+} (Eu{sup 3+}, Tb{sup 3+}) doped NaLa(WO{sub 4}){sub 2} nanocrystals: Synthesis, characterization, and optical properties

Uniform shuttle-like Ln{sup 3+} (Eu{sup 3+}, Tb{sup 3+}) doped NaLa(WO{sub 4}){sub 2} nanocrystals have been solvothermally synthesized, and the size of the nanocrystals could be easily controlled by adjusting the volume ratio of ethylene glycol (EG) to water. Doped with 5 mol% Eu{sup 3+} and Tb{sup 3+} ions, the NaLa(WO{sub 4}){sub 2} nanocrystals showed strong red and green emissions with lifetimes of 0.8 and 1.40 ms, respectively. A high quenching concentration of 15 mol% was observed in Eu{sup 3+}-doped NaLa(WO{sub 4}){sub 2} nanocrystals and 35 mol% in Tb{sup 3+}-doped NaLa(WO{sub 4}){sub 2} nanocrystals. The emission intensity measurements of Eu{sup 3+}-doped NaLa(WO{sub 4}){sub 2} with different sizes indicated that the emission intensity of shuttles with length of 300 nm in average was stronger than that of shuttles with length of 900 nm in average, but was weaker than that of needles with length of 4 and 9 {mu}m in average. - Graphical abstract: Uniform shuttle-like Ln{sup 3+}(Eu{sup 3+}, Tb{sup 3+}) doped NaLa(WO{sub 4}){sub 2} nanocrystals have been solvothermally synthesized in the mixed solvent of ethylene glycol (EG) and water at 180 deg. C for 16 h.