Synthesis and luminescence properties of YVO4:Eu3+ cobblestone - like microcrystalline phosphors obtained from the mixed solvent - thermal method

The mixed solvent-thermal method has been developed for the synthesis of YVO4:Eu3+ luminescent materials in the N, N-dimethylformamide (DMF)/ de-ionized water (DIW) solution. The samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electronic microscope (TEM), UV/vis absorption and photoluminescence spectroscopies. The results demonstrate that we have obtained the uniform YVO4:Eu3+ cobblestone - like microcrystalline phosphors in the mixed solution of DMF and DIW, which are different to the as-obtained YVO4:Eu3+ nanoparticles in pure DIW. And the as - prepared YVO4:Eu3+ microcrystalline particles are composed of numerous nanoparticles. The assembling phenomenon of the nanoparticles is strongly affected by the pH value of the solution and the volume ratio of DMF/DIW. Under UV excitation, the samples can emit the bright red light. While, the photoluminescence (PL) intensities of YVO4:Eu3+ show some difference for samples obtained under the different reaction conditions. This is because that different microstructures of samples result in different combinative abilities between the surface and the adsorbed species so as to produce the different quenching abilities to the emission from Eu3+ ions.