Photoluminescence Characteristics of Eu3+-Doped Double-Perovskite Phosphors

Eu3+-doped triple tellurium double perovskites LiBaLa[TeO6], NaBaLa[TeO6], LiBaBi[TeO6] and NaCaBi[TeO6] were synthesized by the general high temperature solid-state reaction. The crystal phase formations and morphology of the phosphates were confirmed by X-ray powder diffraction (XRD) and scanning electron microscope (SEM) measurements, respectively. The luminescence properties, including the photoluminescence (PL) excitation and emission spectra, decay curves (lifetimes), the color coordinates and the internal quantum efficiency (QE) were investigated. Eu3+-doped LiBaLa[TeO6], NaBaLa[TeO6], and LiBaBi[TeO6] show the dominated electric dipole transition D-5(0) -> F-7(2) with a pure red luminescence color and a fast decay. However, Eu3+-doped NaCaBi[TeO6] presents the dominant reddish-orange emission from magnetic dipole transition D-5(0) -> F-7(1) and a longer luminescence lifetime. The different luminescence features were discussed on the base of crystal structure, where Eu3+ ions have two possible substitutions on A or B sites in double tellurium perovskites. (C) 2014 The Electrochemical Society.