%0 Journal Article
%T Fast Microwave-Assisted Synthesis and Photoluminescence of CaWO4 Nanocrystals
%A Quanguo Li
%A Yanhua Shen
%A Taohai Li
%J Journal of Chemistry
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/952954
%X In this work, CaWO4 nanoparticles have been synthesized by microwave-assisted method at a low temperature of 120¡ãC. The as-prepared powders were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). It is found that the reaction time played an important role in the morphology controlling and crystallinity level of CaWO4 crystals. The effects of photoluminescent properties have a great relationship with crystallinity. 1. Introduction In recent years, with the advance of nanoscale materials science and technology, the synthesis of nanoscale materials with unique properties is becoming more and more important for studying the variation of materials¡¯ properties with size and morphology [1¨C5]. Nanomaterials based on the scheelite-type have attracted considerable interest because of their luminescent property approved use in electrooptic applications [6¨C8]. SrWO4, CaWO4, PbWO4, and BaWO4 were considered to be typical oxides structure of scheelite-type. Locating within tetrahedral O-ion cages, W ions are isolated from each other in the scheelite structure, while Ca, Ba, Sr, and Pb ions are surrounded by eight oxygen ions [9]. CaWO4 with a scheelite structure is an important optical material, which has attracted particular interest because of its applications [10] in quantum electronics or scintillators as laser host material [11, 12]. CaWO4 powders are usually prepared by traditional solid-state reactions which require high temperature and harsh reaction conditions [13]. Recently, CaWO4 nanoparticles have been prepared by various wet chemical methods [14¨C18], which needs long reaction time, or nonaqueous solvents, such as hydrothermal method, citrate complex method, combustion process, coprecipitation, microwave-hydrothermal methods, polymeric precursor method, and microwave-solvothermal methods [19¨C22]. Therefore, to synthesize CaWO4 nanoparticles with a mild method (e.g., low temperature and/or quick reaction time) is of significance in both fundamental and applied studies [23]. In this paper, we report the synthesis, crystal structure, and fluorescence property of CaWO4 nanocrystals, which is prepared from the reaction of CaCl2 and Na2WO4 2H2O in the presence of PEG1000 by fast microwave-assisted method. By controlling the different reaction time, the degree of crystallinity of CaWO4 can be controlled. It means that we can obtain CaWO4 with higher crystallinity target structure by adjusting the reaction time, which is important for the preparation of aimed productions in
%U http://www.hindawi.com/journals/jchem/2013/952954/