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Synthesis and properties of YVO4:Ho and YVO4:Ho,Bi luminescent nanomaterials by combustion method

YVO4:Ho and YVO4:Ho,Bi nanophosphors were synthesized via combustion synthesis using urea as fuel and metal nitrates as precursor. Structures, morphologies and optical properties of YVO4:Ho and YVO4:Ho,Bi nanophosphors annealed at 900 °C were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescent (PL) and photoluminescent excitation (PLE) spectra. The clearly YVO4 tetragonal phase was obtained. The average diameters for the phosphor particles are 20-30 nm. The nanophosphors could be excited by 320 nm which correspond to the VO4 absorption and then PL spectra of YVO4:Ho and YVO4:Ho,Bi nanophosphors are described by the 5F8, 5S2 – 5I8, 5F5 – 5I8 và 5F4, 5S2 → 5I7  transitions of Ho3+ ions at 543, 655 and 755 nm. The effects of Ho3+ and Bi3+ concentrations on structure and optical properties have been investigated