Influence of synthesis conditions on the morphologies of ReBO3 microstructures and white light emission of YBO3:Eu3+ phosphors prepared by an oleic acid-assisted hydrothermal method

Abstract

Uniform ReBO₃ (Re = Y, Dy, Ho, Er and Yb) spherical microstructures were successfully prepared by an oleic acid (OA)-assisted hydrothermal method. In the preparation process of YBO₃, the solvent (water/ethanol) composition, OA amount, pH value, reaction temperature, the mole ratio of Y³⁺/BO₃³⁻ and reaction time would affect the shape, size, crystallinity and structure of the prepared sample. Spherical, porous spherical and 3D hexagonal flowers of YBO₃ crystals can be prepared by changing the synthesis factors, and their possible formation mechanisms were presented based on the experiment results. It is very interesting that YBO₃:3%Eu³⁺ and YBO₃:5%Eu³⁺ samples prepared by the OA-assisted method display a white light emission under excitation at 394 nm, and the quantum yield of the YBO₃:5%Eu³⁺ sample can reach 44.59%. However, when the excitation wavelength is 270 nm, YBO₃:5%Eu³⁺ shows orange-red emission and the quantum yield can reach 79.73%.These results may open up a new opportunity for YBO₃:Eu³⁺ phosphors in the application of the white light emitting diodes (WLEDs).