Preparation and fluorescence characterization of monodisperse core-shell structure SiO 2 @SiO 2 : Tb(1,2-BDC) 3 phen microspheres by a sol-seed method

The SiO2 @SiO2 :Tb(1,2-BDC)3 phen microspheres with monodispersed core-shell structure, are kind of fluorescent particles, which are prepared by a seeded growth method under the catalysis of glacial acetic acid (1,2-BDC, 1,2-benzenedicarboxylic acid; phen, 1,10-phenanthroline). Firstly, silica seed was fabricated by the hydrolysis of ethyl orthosilicate, and the Tb(1,2-BDC)3 phen was prepared by using 1,2-BDC and phen. Then, a thin mesoporous silica shell doped with Tb(1,2-BDC)3 phen was grown on the prepared monodisperse silica colloids. The prepared phosphor was analyzed by Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, thermogravimetric and fluorescence spectroscopy. The experimental results showed that the diameter of the SiO2 @SiO2 :Tb((1,2-BDC)3 phen microsphere was about 200 nm with a typical core-shell structure, among which the diameter of the silica core was 180 nm, and that of the mesoporous silicon shell doped with terbium complex was about 10 nm. The fluorescence intensity of SiO2 @SiO2 :Tb((1,2-BDC)3 phen microsphere is nearly three times higher than that of Tb((1,2-BDC)3 phen complexes. The prepared microspheres could be widely used in bio-imaging, optoelectronic appliances and medical diagnosis.