Synthesis and Luminescence Properties of Core-Shell-Shell Composites: SiO2@PMDA-Si-Tb@SiO2 and SiO2@PMDA-Si-Tb-phen@SiO2

Abstract

Two novel core-shell composites SiO2@PMDA-Si-Tb, SiO2@PMDA-Si-Tb-phen with SiO2 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)2C6H2(CONH(CH2)3Si(OCH2CH3)3)2 (abbreviated as PMDA-Si) was used as the first ligand and phen as the second ligand. Furthermore, the silica-modified SiO2@PMDA-Si-Tb@SiO2 and SiO2@PMDA-Si-Tb-phen@SiO2 core-shell-shell composites were also synthesized by sol-gel chemical route. An amorphous silica shell was coated around the SiO2@PMDA-Si-Tb and SiO2@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.

Tailoring the Design of a Lanthanide Complex/Magnetic Ferrite Nanocomposite for Efficient Photoluminescence and Magnetic Hyperthermia Performance

“…It is not surprising that the Eu­(TTA) 3 Phen embedded in the second layer of silica appears as the prominent dark contrast shell in between the SiO 2 spacer and the outermost SiO 2 layer in the TEM image. It is established that lanthanide complexes encapsulated either as a core within silica nanoparticles or as an intermediate shell between silica nanoparticles and the outermost silica layer (similar to this work) can be visualized easily in the TEM image by their discrete dark contrast in regard to SiO 2 . ,, The dark contrast of lanthanide complexes in all of these reports as well as in Figure B of this work is mainly a consequence of the high atomic number of lanthanides. In Figure D, it is evident that the thickness of the silica spacer that separates the Eu­(TTA) 3 Phen layer from MnFe 2 O 4 core in Eu-MnFe 2 O 4 nanoparticles is ∼10 nm.…”

Rapid Reduction and Recovery of Au(III) in Water by Hollow Polym‐phenylenediamine Nanospheres

“…The absorption peaks around 3170 cm −1 and 1624 cm −1 can be attributed to the polysome and aromatic ring skeleton structures, respectively.The absorption peak at 1400 cm −1 belonged to the −NH− group. In the infrared spectrum of SiO 2 @PmPD, the absorption peak at 1105 cm −1 was the anti‐symmetric stretching vibration of Si−O−Si, and the absorption peak at 951 cm −1 was the symmetrical stretching vibration of Si−O [7] . The peak at 619 cm −1 could be attributed to the interposition substitution of benzene ring [5] .…”

“…In the infrared spectrum of SiO 2 @PmPD, the absorption peak at 1105 cm À 1 was the anti-symmetric stretching vibration of SiÀ OÀ Si, and the absorption peak at 951 cm À 1 was the symmetrical stretching vibration of SiÀ O. [7] The peak at 619 cm À 1 could be attributed to the interposition substitution of benzene ring. [5] However, in the hollow PmPD, the characteristic peaks at 1105 cm À 1 and 951 cm À 1 obviously weakened or disappeared, indicating that the core (SiO 2 ) of SiO 2 @PmPD was almost completely etched after HF treatment.…”

Controlled synthesis and luminescence properties of core-shell-shell structured SiO2@AIPA-S-Si-Eu@SiO2 and SiO2@AIPA-S-Si-Eu-phen@SiO2 nanocomposites

“…Since the core-shell structured nanocomposites were coated with a silica shell, which the high vibration energies loss of the ligand molecules (AIPA-S-Si, phen) or other quenching sites located at the surface of the core-shell structured nanocomposite could largely reduce. The silica shell can protect the rare earth complexes from quenching by the external environment 21 . Thus, the luminous intensity of the core-shell-shell structured nanocomposite is stronger than that of the corresponding core-shell structured nanocomposite.…”

“…Unfortunately, rare earth organic complex themselves are still restricted from being utilized in practical applications due to their poor thermal and mechanical stability 13 . If the rare earth organic complex were immobilized on the surface of the silica, the silica core can reduce the skeleton vibration of the ligand, thereby effectively improving the stability and luminescence intensity of the complex [21][22][23] . The nanocomposites with silica as the core and rare earth complexes as the shell have good luminous properties, which make them more widely used.…”