Hydrothermal synthesis and luminescence property of tetragonal LaVO4:Eu³⁺sheaves

摘要

LaVO₄:Eu³⁺sheaves with tetragonal (t-) structure are synthesized with EDTA from a mixed water/ethylene glycol solvent by hydrothermal method. The t-LaVO₄:Eu³⁺sheaves composed by uniform nanorods with different diameters are obtained by varying the pH values of the initial solution from 8 to 11 at the fixed volume ratio of 4:1. And the diameter of the nanorods at both ends of the sheaves have a trend of thickness with the pH increase of the initial mixed solution. It is found that the LaVO₄:Eu³⁺sheaves synthesized at higher pH values have better crystallization degree, bigger unit cell volume, smaller energies values of direct band gap and stronger luminescence properties. In addition, the volume ratio of water to ethylene glycol has the influence on the microstructure and luminescence property of the LaVO₄:Eu³⁺nanocrystals. EDTA and EG both play a crucial role in the morphologies of LaVO₄:Eu³⁺crystals. LaVO₄:Eu³⁺sheaves synthesized at water/ethylene glycol volume ratio of 3:1 have exhibited the strongest luminescence property.