A methanol-water mixed solvent was used as a reaction medium for the preparation of Eu3+-doped YVO4 phosphor materials. These were synthesized by a solvothermal method at 150°-300°C using a 10 vol% solution of water in methanol as the reaction medium followed by calcination at 1000°-1200°C. The phase composition and optical properties of the products were characterized by X-ray diffraction, scanning electron microscope, and photoluminescence spectroscopy. The powders obtained were composed of spherical particles ∼0.5 μm in size, with an internal structure that was different for samples prepared under subcritical and supercritical conditions of methanol. After the calcination, the powders obtained at 240°-300°C retained the initial raspberry-like morphology, whereas the morphology of samples prepared at 150°-210°C changed significantly due to noticeable sintering. The fluorescence intensity exhibited by the prepared samples was higher than the fluorescence intensity shown by one of the best commercial YVO4:Eu phosphors having a large particle size.
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