Luminescence Tuning Mechanism of La0.827Al11.9O19.09:Eu2+,Mn2+ Phosphor for Multi-Color Light-Emitting Diodes

Abstract

La0.827Al11.9O19.09:Eu2+,Mn2+ (LAO:Eu,Mn) was prepared for ultraviolet light-emitting diodes (UV LEDs) application. LAO has a distorted magnetoplumbite structure which can provide 12-coordinated site for an La ion and two different sites for Al ions, tetrahedral and octahedral sites. Co-activators, Eu and Mn, were substituted for La site and Al sites of LAO, respectively. The LAO: Eu, Mn phosphor has three emission bands composed of blue, green, and red, and emitting colors can be controlled from blue to red by manipulating concentration of the activators. The energy transfer mechanism among lanthanide ions in the phosphor was investigated by photoluminescence and electron paramagnetic resonance techniques. The energy transfer from Eu to Mn was revealed to occur via dipole-quadrupole interaction. The critical distance for the energy transfer was calculated to be about 9 angstrom by two methods. In addition, efficient multi-color LEDs were fabricated by LAO:Eu, Mn phosphors showing multi-color luminescence. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3606474] All rights reserved.