Optical properties of YVO₄:Eu³⁺ nano-phosphors at different europium concentrations

In the present work, YVO₄:Eu³⁺ nano-phosphors are synthesized for various concentrations of europium. X-ray diffraction, Fourier transform infrared spectroscopy, UV–visible spectroscopy and photoluminescence spectroscopy are used for the characterization of the YVO₄:Eu³⁺ nano-phosphors. It is observed that the crystallite size decreases with the increase of the europium concentration. The Fourier transform infrared spectra show crystal structure with tetragonal phase. The phosphors synthesized at 5 mol% exhibit sharp peaks with higher intensities, which reflect better luminescent properties as compared to the samples at other concentration through excitation at 325 nm. The peaks between 250 and 350 nm are due to the charge transfer transitions from ligand to europium ion in the UV–visible spectroscopy. This study concludes that with the increase in the concentration of europium up to 5 mol%, the luminescence intensity increases and then decreases for further increase in the europium concentrations. The results are likely to be useful for the understanding the role of the optimum europium concentration in the nano-phosphors. (author)