Hydrothermal synthesis and luminescent properties of NaLa(MoO4)2:Eu3+,Tb3+ phosphors

Abstract

Eu3+ and Tb3+ co-doped NaLa(MoO4)2 phosphors with various shapes have been synthesized by a simple conventional hydrothermal method. The morphology of the materials was found to be manipulated by changing the pH value of the precursor hydrothermal media. Uniform NaLa(MoO4)2 3D microspheres could be trapped at pH 5 and the spindle-like NaLa(MoO4)2 microstructures were obtained at pH 7. When the pH value was adjusted to 9, the flower-like NaLa(MoO4)2 microstructures were obtained. The luminescent properties of the NaLa(MoO4)2:Eu3+/Tb3+ samples with different morphologies prepared at different starting pH values were studied. The results show that the emission intensity of the product obtained at pH 5 is the strongest. Besides, under ultraviolet excitation the luminescence colors of NaLa(MoO4)2 samples co-doped with Eu3+ and Tb3+ can be tuned from red, through yellow and green–yellow, to green by simply adjusting the relative doping concentrations of the activator ions. This merit of multicolor emissions in the visible region endows the as-prepared products with potential application in the fields of light-display systems and optoelectronic devices.