Preparation, characterization and Hg(II)-sensing behavior of an up-conversion nanocomposite grafted by a rhodamine derived probe: A potential application for eco-industrial park

摘要

In the present work, we designed and synthesized a rhodamine derived "off-on" probe for Hg(II) detection, which might be potentially used in eco-industrial park. By grafting this probe onto the surface of an up-conversion NaYF_4:Yb~(3+)/Er~(3+) excitation source, a Hg(II) sensing system was resulted. The nanocomposite was carefully characterized and analyzed by electron microscopy images, XRD analysis, IR spectra, thermogravimetry, UV-Vis absorption and fluorescence emission. Experimental data confirmed the structure of the nanocomposite. There was an efficient energy transfer between the excitation source and the probe, which made the nanocomposite a promising sensing system. The spectral response towards Hg(II) suggested that the fluorescence intensity of the nanocomposite increased with the increasing Hg(II) concentration, showing "off-on" effect. What's more, the fluorescence signal of the nanocomposite was insensitive towards other metal ions, showing unique selectivity towards Hg(II).