Study on Na3Lu1-xEux(PO4)(2) phosphor: High efficient Na3Eu(PO4)(2) red emitting phosphor with excellent thermal stability

摘要

High efficient Na-3(Lu1-xEux)(PO4)(2) orthophosphates phosphors were synthesized by conventional solid state reaction method. The obtained phosphors crystallized in the orthorhombic system with the space group Pca21. Since the crystal structure of the phosphor is composed of isolated PO4 tetrahedra, the average distance between rare earth ions was distant. As the concentration of Eu3+ activator ion reaches to 100%, reduced Judd-Ofelt parameter ratio of Omega(2)/Omega(4) implies the improvement of the symmetry environment around Eu3+ ion and from the prolonged lifetime of D-5(0) -> F-7(2) transition we inferred no-concentration quenching in this phosphor. Furthermore, due to the better crystallinity of Na3Eu(PO4)(2) phosphor compared to the mixed crystals Na-3(Lu1-xEux)(PO4)(2), the internal quantum efficiency of the Na3Eu(PO4)(2) phosphor reaches the high value up to 99% under near-ultraviolet (393 nm) excitation. Temperature dependent emission spectra revealed that Na3Eu(PO4)(2) phosphor possesses stable emission of 80% at 423 K compared to room temperature. Due to high quantum efficiency and excellent thermal stability, Na3Eu(PO4)(2) has potential application as reddish-orange phosphors. (C) 2019 Elsevier B.V. All rights reserved.