Hydrothermal synthesis, multicolor tunable luminescence and energy transfer of Eu3+ or/and Tb3+ activated NaY(WO4)2 nanophosphors

Abstract

Eu3+ and/or Tb3+ doped NaY(WO4)2 nanomaterials have been successfully synthesized by one-step hydrothermal method. The samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, X-ray energy dispersive spectroscopy, and photoluminescence spectra. The results show that the novel nanoplates with a diameter of 300–600 nm and the thickness of 20–25 nm are observed. Under the excitation of 246 or 230 nm, individual RE3+ ions activated NaY(WO4)2 phosphors exhibit excellent emission properties in their respective regions. The as-prepared Eu3+ or Tb3+ doped samples show strong red and green emission, originating from the allowed 5D0 → 7FJ (J = 0, 1, 2) transition of the Eu3+ ions and the 5D4 → 7FJ (J = 6, 5, 4, 3) transition of the Tb3+ ions. In addition, by properly tuning the relative concentration of Eu3+ ions in the case of Eu3+ and Tb3+ co-doped systems, tunable emissions in a single component are obtained under the excitation of 230 or 395 nm. Moreover, an energy transfer from Tb3+ to Eu3+ is observed, which has been justified through the luminescence spectra and the fluorescence decay curves. Furthermore, the corresponding luminescence and energy transfer mechanism have been proposed in optical transitions and possible energy transfer scheme. These results indicate that Eu3+ and Tb3+ doped NaY(WO4)2 phosphors will find potential application in the field of solid-state lighting.