Monazite and zircon type LaVO4:Eu nanocrystals - Synthesis, luminescent properties, and spectroscopic identification of the Eu3+ sites

Abstract

Pure monoclinic- (m) and tetragonal (t) LaVO4:Eu nanocrystals were prepared by a facile citric anion- and EDTA (ethylenediaminetetraacetic acid)-assisted hydrothermal method, respectively. The structure is characterized by XRD, Raman spectroscopy, and electron microscopy. Besides structure characterization, site-selective emission spectroscopy was used to investigate the relationship between the microstructure and luminescent characters of the m- and t-LaVO4:Eu nanocrystals. The results show that for both the m- and tLaVO4:Eu nanocrystals, the Eu3+ ions occupy two types of sites, one that is the same as that of the corresponding bulk and the other that is specific to the surface states of the nanocrystals. These investigations not only provide important experimental evidence for rare earth luminescence studies, but also disclose the correlation between the microstructure and luminescence behavior, which could be used as a guide to the design and synthesis of novel luminescence materials. It is also shown that t-LaVO 4:Eu is a promising luminescence material with a high quantum yield and low cost. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.