Abstract
Two novel core-shell composites SiO&sub2;@PMDA-Si-Tb, SiO&sub2;@PMDA-Si-Tb-phen with SiO&sub2; 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)&sub2;C₆H&sub2;(CONH(CH&sub2;)&sub3;Si(OCH&sub2;CH&sub3;)&sub3;)&sub2; (abbreviated as PMDA-Si) was used as the first ligand and phen as the second ligand. Furthermore, the silica-modified SiO&sub2;@PMDA-Si-Tb@SiO&sub2; and SiO&sub2;@PMDA-Si-Tb-phen@SiO&sub2; core-shell-shell composites were also synthesized by sol-gel chemical route. An amorphous silica shell was coated around the SiO&sub2;@PMDA-Si-Tb and SiO&sub2;@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.