Enhanced blue emission and EPR study of LaMgAl11O19 Eu phosphors

Europium doped LaMgAl11O19 phosphor was prepared by the combustion met hod The as-prepared and post-treated (1350 degrees C 10 h 5% H-2+95% N-2) phosphors wen investigated by X-ray diffraction (XRD) Fourier transform infrared (FT-IR) scanning electron microscopy (SEM) photoluminescence (PL) and electron paramagnetic resonance (EPR) techniques XRD patterns show that LaMgAl11O19 Eu phosphors have hexagonal structure FT-IR spectrum exhibits absorption bands corresponding to the stretching vibration of AlO4 and AlO6 Morphological studies reveal that this phosphor has faceted plates of varying sizes and shapes The as-prepared LaMgAl11O19 Eu phosphor consists of both Eu3+ and Eu2+ ions The phosphor exhibits a bright blue emission at 450 nm (4f(6)5d -> 4f(7) transition of Eu2+) On post-treating the phosphor we are able to enhance the blue emission efficiency by 330% The process was detected from the evolution of excitation emission and EPR spectra and the results are discussed (C) 2010 Elsevier B V All rights reserved