White light-emitting properties of NaGdF4 nanotubes through Tb3+, Eu3+ doping

Abstract

White light-emitting NaGdF₄ phosphor samples based on efficient energy transfer between Tb³⁺ and Eu³⁺ were synthesized via a conventional hydrothermal reaction process. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra and lifetime measurement were performed to characterize the samples. The energy transfer process between Tb³⁺ and Eu³⁺ was demonstrated to be a resonant type via a dipole–dipole interaction mechanism. Furthermore, for NaGdF₄:Tb³⁺,Eu³⁺, white light emission can be realized in the single-phase NaGdF₄ host by reasonably adjusting the relative doping concentrations of Tb³⁺ and Eu³⁺ under ultraviolet excitation. Due to their excellent PL properties and good CIE chromaticity coordinates, the as-prepared Tb³⁺, Eu³⁺ co-doped NaGdF₄ nanocrystalline phosphors have potential application in field-emitting displays.