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

Abstract

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.