Synthesis and fluorescence properties of CdTe:Eu3+ nanocrystals and core–shell SiO2-coated CdTe:Eu3+ nanospheres
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Eu3+ doped-CdTe (CdTe:Eu3+) nanocrystals were prepared via a facile hydrothermal method, and Eu3+ was successfully incorporated into the crystal lattice of CdTe and measured by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) absorption spectroscopy and fluorescence emission. The CdTe:Eu3+ nanocrystals still have a cubic crystal structure, and the corresponding XRD peaks of CdTe:Eu3+ nanocrystals shift to larger angles compared with those of pure CdTe. The CdTe:Eu3+ nanocrystals are monodisperse and the particles size is about 2–4 nm. Compared with pure CdTe, the CdTe:Eu3+ nanocrystals have larger band gap and thus exhibit blueshift in the emission spectra, which could be accounted for by the energy transfer between Eu3+ and CdTe. To enhance the stability and functionality of CdTe:Eu3+ nanocrystals, the CdTe:Eu3+ nanocrystals were coated with SiO2 and the core–shell SiO2-coated CdTe:Eu3+ nanocrystals (CdTe:Eu3+@SiO2) were prepared via micro-emulsion method. TEM results show that CdTe:Eu3+ nanocrystals are uniformly dispersed in the shell, and CdTe:Eu3+@SiO2 nanospheres are uniformly spherical with an average diameter of about 75 nm. The fluorescence emission of CdTe:Eu3+@SiO2 (567 nm) shows a blueshift compared with that of CdTe:Eu3+ nanocrystals (632 nm), possibly because of altered surface properties after SiO2 coating. CdTe:Eu3+ and CdTe:Eu3+@SiO2 with tunable photoluminescence are potentially useful in fabricating optical and bioimaging devices.
KeywordsCdTe:Eu3+ nanocrystals Doping Core–shell SiO2 Fluorescent properties
This work was financially supported by the National Natural Science Foundation of China (No. 21364007), the Natural Science Foundation of Inner Mongolia (No. 2016MS0201) and the Program for Young Talents of Science and Technology of Baotou Teachers College (No. 01135003).
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