Synthesis and Luminescence Properties of Core-Shell-Shell Composites: SiO(2)@PMDA-Si-Tb@SiO(2) and SiO(2)@PMDA-Si-Tb-phen@SiO(2)

Two novel core-shell composites SiO(2)@PMDA-Si-Tb, SiO(2)@PMDA-Si-Tb-phen with SiO(2) as the core and terbium organic complex as the shell, were successfully synthesized. The terbium ion was coordinated with organic ligand forming terbium organic complex in the shell layer. The bi-functional organosilane ((HOOC)(2)C(6)H(2)(CONH(CH(2))(3)Si(OCH(2)CH(3))(3))(2) (abbreviated as PMDA-Si) was used as the first ligand and phen as the second ligand. Furthermore, the silica-modified SiO(2)@PMDA-Si-Tb@SiO(2) and SiO(2)@PMDA-Si-Tb-phen@SiO(2) core-shell-shell composites were also synthesized by sol-gel chemical route. An amorphous silica shell was coated around the SiO(2)@PMDA-Si-Tb and SiO(2)@PMDA-Si-Tb-phen core-shell composites. The core-shell and core-shell-shell composites both exhibited excellent luminescence in solid state. The luminescence of core-shell-shell composites was stronger than that of core-shell composites. Meanwhile, an improved luminescence stability property for the core-shell-shell composites was found in the aqueous solution. The core-shell-shell composites exhibited bright luminescence, high stability, long lifetime, and good solubility, which may present potential applications in the bio-medical field.