Controlled hydrothermal synthesis and luminescent properties of Y2WO6:Eu3+ nanophosphors for light-emitting diodes

In this paper, Eu 3+ -doped yttrium tungstate (Y 2 WO 6 ) nanophosphors with different morphologies have been synthesized by a hydrothermal method with the assistance of cetyltrimethyl ammonium bromide. X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and photoluminescence spectroscopy (PL) were used to characterize the products. The pH value of the starting solution plays a crucial role in the structures and morphologies of the samples. When the precursors synthesized under alkaline condition are annealed at 1100 °C in the air, the pure monoclinic Y 2 WO 6 phase can be obtained. The results of HRTEM and SAED are consistent with those of the XRD patterns, confirming the high crystallinity of the products. A detailed study of the optical properties, including the UV–Vis diffuse reflection spectra, the excitation and emission spectra, CIE coordinate, and color purity of Y 2 WO 6 :Eu 3+ nanophosphors with different doping concentrations, are presented here. The critical distance R c and energy transfer mechanism for the concentration quenching of Eu 3+ ions are discussed in detail. In addition, the decay time and the thermal stability of the samples have been also investigated elaborately. The PL properties of the as-synthesized materials indicate promising applications in UV-pumped red light-emitting diodes.