Methanol–Water System for Solvothermal Synthesis of YVO₄:Eu with High Photoluminescent Intensity

Abstract

A methanol-water mixed solvent was used as a reaction medium for the preparation of Eu 31 -doped YVO 4 phosphor materials. These were synthesized by a solvothermal method at 1501-3001C using a 10 vol% solution of water in methanol as the reaction medium followed by calcination at 10001-12001C. 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 B0.5 lm 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 2401-3001C retained the initial raspberry-like morphology, whereas the morphology of samples prepared at 1501-2101C 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 YVO 4 :Eu phosphors having a large particle size.

Facile Synthesis of Ce3+, Eu3+Co-Doped YAG Nanophosphor for White Light-Emitting Diodes

“…At the sintering temperature higher than 900 • C, the pattern of the samples can be assigned exactly to the standard data of cubic YAG, and there is no diffraction peak corresponding to any other materials or allotropic phase, which suggests that a pure crystalline compound is obtained at 1000 • C, and Ce 3+ and Eu 3+ can be successfully doped in the YAG host lattice without causing any significant change. Compared with the conventional solid-state reactions, the sintering temperature used in our experiments is much lower, 22 which may be attributed to the starting materials being homogeneously mixed at the molecular level in the solution, the hydrothermal process offering higher diffusivity and lower viscosity due to the elevated temperatures, 23 and the added citric acid acting as fuel to promote the formation of YAG. In addition, the crystallinity of YAG cubic phase increases with the increasing sintering temperatures, which can also be confirmed by the decrease of the full-width at half maximum (FWHM) of the diffraction peaks in the XRD patterns.…”

Preparation and Size Control of Sodium Niobate Nanocube at Various Solvothermal Conditions

“…Where D is the crystal size in nanometers, λ is the wavelength of Cu Kα (wavelength: 0.15406 nm), β is the full width at half maximum (FWHM) intensity in radians, and θ is the diffraction peak angle [14,21,22]. The obtained β value of the diffraction line includes errors from the experimental conditions such as noise and the slit width of the X-ray diffractometer.…”

New Shape-Controlled Nanocrystalline SrSiO₃ Photocatalyst: Template-Free Syntheses and Photocatalytic Activity

“…Such as mild synthesis condition, highly crystallinity, highly pure powders with narrow size-distribution, lower energy consumption [5] . The solvothermal process is an extension of the hydrothermal methods, in which chemical reactions are carried out in an autoclave in the presence of a nonaqueous solvent above room temperature and at elevated pressure, which allow for greater solubility of solid for the reaction process, and the desired compounds can be synthesized at lower temperatures compared with the solid-state reaction method [6] . Controlling the morphology of nanostructures is central to many applications because it provides an effective means of tailoring the electronic, optical and catalytic properties of its structures [7][8][9] .…”