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Advances in Materials Science and Engineering
Volume 2011, Article ID 790517, 7 pages
http://dx.doi.org/10.1155/2011/790517
Research Article

Near UV-Blue Excitable Green-Emitting Nanocrystalline Oxide

1Programa de Posgrado en Física de Materiales, CICESE-UNAM, Carretera Ensenada-Tijuana No. 3918, Zona Playitas, C.P. 22860, Ensenada, BC, Mexico
2Laboratorio de Investigaciones en Nanociencias y Nanotecnología (LINAN) y División de Materiales Avanzados, IPICYT, Camino a la Presa San José 2055, Lomas 4a. Sección, San Luis Potosí 78216, Mexico
3Centro de Nanociencias y Nanotecnología Universidad Nacional Autonóma de México, Km 107 Carretera Tijuana-Ensenada, 22800 Ensenada, BC, Mexico

Received 1 October 2010; Accepted 4 April 2011

Academic Editor: Peter Majewski

Copyright © 2011 C. E. Rodríguez-García et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Green-emitting Eu-activated powders were produced by a two-stage method consisting of pressure-assisted combustion synthesis and postannealing in ammonia. The as-synthesized powders exhibited a red photoluminescence (PL) peak located at 𝜆 = 6 1 6  nm when excited with 𝜆 = 3 9 5  nm UV. This emission peak corresponds to the 5D07F2 transition in Eu3+. After annealing in ammonia, the PL emission changed to an intense broad-band peak centered at 𝜆 = 5 0 0  nm, most likely produced by 4f65d1→4f7 electronic transitions in Eu2+. This green-emitting phosphor has excitation band in the near UV-blue region ( 𝜆 = 3 0 0 –450 nm). X-ray diffraction analysis reveals mainly the orthorhombic EuAlO3 and Al2O3 phases. Transmission electron microscopy observations showed that the grains are formed by faceted nanocrystals (~4 nm) of polygonal shape. The excellent excitation and emission properties make these powders very promising to be used as phosphors in UV solid-state diodes coupled to activate white-emitting lamps.