Synthesis and Photoluminescence of Rhombic NaLa(MoO4)2:Ln3+ Nanocrystals.

Rhombic NaLa(MoO4)2:Ln3+ (Ln = Eu and Tb) nanocrystals were synthesized by a hydrothermal method. The structures and morphologies of the nanocrystals were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The results indicated that the crystalline size increased with increasing Na2MoO4 content. The photoluminescence properties of NaLa(MoO4)2:Ln3+ nanocrystals were investigated in detail. In the emission spectra of NaLa(MoO4)2:Eu3+ nanocrystals, the 5D0 --> 7F2 is dominant, and the peak positions and spectral shapes of emissions were independent of Eu3+ concentration. The luminescence intensity increased with increasing Eu3+ concentration, up to about 10 mol%, and then decreased. In the emission spectra of NaLa(MoO4)2:Tb3+ nanocrystals, the 5D4 --> 7F5 is dominant. The sample with a dopant concentration of 20 mol% showed the highest emission intensity.