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

Abstract

In this paper, Eu3+-doped yttrium tungstate (Y2WO6) 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 Y2WO6 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 Y2WO6:Eu3+ nanophosphors with different doping concentrations, are presented here. The critical distance R c and energy transfer mechanism for the concentration quenching of Eu3+ 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.