Photoluminescence properties of Eu3+-and Tb3+-doped YAlO3 phosphors for white LED applications

摘要

Eu3+-and Tb3+-doped YAlO3 phosphors are prepared by solid-state reaction method and their photoluminescence properties are investigated as functions of the Eu3+ and Tb3+ concentrations. The phosphors crystallize in the orthorhombic crystal structure. Under near-ultraviolet excitation (398 nm), the emission spectra of Y1-xAlO3:xEu(3+)(0.02 <= x <= 0.1) phosphors show several strong peaks at 593, 616, 655, and 697 nm, which are attributed to the D-5(0) -> F-7(J) (J=1, 2, 3, and 4) transitions of Eu(3+)ions. A high value of (D-5(0)-> F-7(2))/(D-5(0)-> F-7(1)) is obtained for the Y1-xAlO3:xEu(3+)phosphors, indicative of high-purity red emission. Furthermore, the emission peaks of Y(1-)yAlO(3):yTb(3+) (0.04 <= y <= 0.2) phosphors are detected at 489, 544, 585, and 621 nm, which are due to the D-5(4)-> F-7(6), D-5(4)-> F-7(5), D-5(4)-> F-7(4), and D-5(4)-> F-7(3) transitions of the Tb(3+)ions, respectively. The emission peak (544 nm) corresponding to the D-5(4)-> F-7(5) transition is the most intense, which is advantageous for high green color purity. White light can be obtained by combining blue GaN LED chips with the red Y1-xAlO3:xEu(3+) and green Y(1-)yAlO(3):yTb(3) phosphors prepared in this study. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.