Hydrothermal Synthesis and Microstructural, Optical Properties Characterization of YVO₄Phosphor Powder

Abstract

The phonon energy of YVO4 crystal is lower than other usual compounds of salt. So it is suitable as host material for down-conversion materials. Hydrothermal method was adopted to synthesize YVO4 phosphor powder with the use of yttrium oxide and sodium vanadate as raw material. The change in the relative integral intensity of the (200) and (112) diraction peaks indicates that macroscopic stress in the lattice obviously changes with the elevated hydrothermal reaction temperature. The YVO4 phosphor powder synthesized involves a certain agglomeration of small particles. The phonon vibration in the YVO4 originates mainly from the internal vibrations in the vanadiumoxygen tetrahedron, in addition to the YO and OH vibrations. Due to a low phonon energy of only 2.8188 × 10 −21 J, YVO4 helps to improve the down-conversion eciency of rare-earth ions. A bandgap value of approximately 3.8 eV for the synthesized YVO4 powders leads to good absorption properties in the ultraviolet region. Upon excitation by the 320 nm ultraviolet photon, the intrinsic emission of YVO4 powders is annihilated, and a broadband emission of VO 3− 4near 450 nm is observed at room temperature. The YVO4 phosphor powder synthesized at 180• C exhibits the maximum photoluminescence intensity because of its excellent crystallization.

Luminescence investigation of a cerium‐doped yttrium vanadate phosphor

“…A weak peak at 450 cm −1 could be attributed to yttrium–oxygen bonds. The solid peak at 806 cm −1 was due to movement of VO 4 . The 1635 cm −1 area unit corresponded to OH stretching vibration modes for coordinated water.…”

“…From Figure and in Table it can be seen that as crystal size diminishes, dislocation density and strain values increase. This difference could be due to enhancement of the surface effect . From exploratory outcomes it was inferred that there was no considerable shift in the peak positions of PXRD patterns of Ce‐doped YVO 4 .…”

Effect of Trisodium Citrate on the Morphology and Luminescence Properties of Hydrothermally Synthesized YVO4Phosphor

“…YVO 4 has a wide absorption band (200-320 nm) rather than a sharp absorption edge. Hence, the excitation wavelength was 300 nm determined in terms of the absorption spectrum reported elsewhere [8] rather than excitation spectrum. The range of the test wavelength was 340 nm to 800 nm.…”

“…Authors themselves once fabricated YVO 4 phosphor powders by using hydrothermal method. They carefully studied the effect of hydrothermal temperature on the microstructure, the absorption and luminescent properties of the phorphor powders [8]. Besides, they also fabricated spherical YVO 4 phosphor powders at molar ratio of cit 3− to Y 3+ of 2:1 by using hydrothermal method and studied the effect of the annealing temperature on the microstructure and the luminescent properties [9].…”

Estudo das propriedades luminescentes de íons Terras Raras em matrizes compósitas à base de alumina obtidas por pirólise de aerossol

“…Dessa forma, o YVO4 é importante por exibir uma banda de absorção intensa (OVO4 3-) que permite transferir energia para os íons európio de forma eficiente, aumentando deste modo a intensidade de emissão. Nanopartículas de YVO4:Eu 3+ podem ser sintetizadas por co-precipitação [GIAUME et al, 2005], microemulsão reversa [ALTHUES et al, 2007] e síntese hidrotermal [ZHANG et al, 2014]. Neste trabalho, optou-se pela metodologia de co-precipitação na presença de citrato de sódio, a qual limita o crescimento das partículas e impede a agregação [GIAUME et al, 2005], visto que uma das etapas necessárias à síntese é a obtenção de uma suspensão estável como precursor da metodologia SP.…”