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A novel near infrared long lasting phosphor MgGa2O4:Cr3+ was successfully prepared by a hydrothermal method and a solid state reaction method.

In this work, Eu 3? -doped YVO 4 phosphors were prepared via the solid-state reaction and the combustion method and the role of the synthesis process on the structural and emission properties of YVO 4 :Eu 3? was investigated. Combustion synthesis yielded tetragonal phase with the space group I4 1 /amd at a relatively low temperature and within short duration. The infrared spectra confirmed the characteristic bands of Y-O and V-O at around 450 and 830 cm -1 , while the samples prepared by combustion route exhibited C-O band and O-H-O bending vibrations at 1376 and 1637 cm -1 , respectively. The band gap energy of YVO 4 , prepared by different methods, was found in the range of 3.6-3.73 eV. Upon UV excitation, the Eu 3? -activated samples exhibited characteristic red-orange emission lines generated from 5 D 0 ? 7 F 1,2 transitions of Eu 3? ions, respectively. The red-to-orange emission intensity ratio was found to be around 4.6 for all samples and proved to be competitive with the commercially available red phosphors. However, Y 1-x Eu x VO 4 phosphors, synthesized by solid-state reaction technique, exhibited elevated Eu 3? solubility and higher emission intensity than the samples prepared by combustion route owing to the larger crystallite size and minor C-O and O-H bonds. The critical concentration of Eu 3? ions for the maximum emission was estimated to be 2.0 and 0.5 mol% for the samples obtained by solid-state reaction and combustion method, respectively. The present phosphors were observed to be effectively excitable via the broad range of UV lights and were proved to be compatible with the UV LEDs.

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