Synthesis of Novel Luminescent Double-Decker Silsesquioxanes Based on Partially Condensed TetraSilanolPhenyl POSS and Tb3+/Eu3+ Lanthanide Ions

In this study, novel lanthanide-containing double-decker polyhedral oligomeric silsesquioxanes (POSS) were prepared by combining the partially condensed TetraSilanolPhenyl POSS with terbium (Tb3+) and europium (Eu3+) ions. This open-cage POSS possesses four diametrically opposite silanol groups that are able to coordinate, under mild conditions, different luminescent ions through a simple corner-capping method. The two metal-containing POSS functionalized with Tb3+ and with an equimolar combination of Tb3+ and Eu3+ show a completely condensed structure with different luminescent properties. Their emission features depend on the chemical nature of the metal ions incorporated in the framework. An improved stokes shift was detected in the bimetallic compound containing both the Tb3+ and Eu3+ ions, promoted by the occurrence of a Tb3+→Eu3+ energy transfer mechanism. These characteristics identify this metal-functionalized silica platform as a potential candidate for the development of novel luminescent devices.

Color-Transformable Silicone Elastomers Prepared by Thiol-Ene Reaction with Potential Application in UV-LEDs

A series of high-efficiency, full-color fluorescent elastomers based on polysiloxane matrix prepared by an easy thiol-ene "click" reaction is reported here. It is found for the first time that the same elastomer can emit transformable colors by conveniently altering the excitation wavelength because of the effect of energy transfer and the "fluorescence switch" of lanthanide ions. A fluent change in emission colors can also be feasible and conveniently reproducible by varying the stoichiometric ratio of lanthanide ions and rhodamine-B in solution and in polymer elastomers. The obtained elastomers are further coated onto commercially available UV-LED cells from the solution medium followed by an in situ cross-linking step.

Studies on the gel behavior and luminescence properties of biological surfactant sodium deoxycholate/rare-earth salts mixed systems

Luminescent hydrogels were facilely designed through supramolecular self-assembly of biological surfactant (sodium deoxycholate, NaDC) and lanthanide salt (Eu(NO3)3). The microstructures of the hydrogels were characterized by transmission electron microscopy (TEM), high-resolution TEM (HR-TEM) and field emission scanning electron microscopy (FE-SEM), from which nanofibers and tiny particles were observed. The arrangement of the deoxycholate and metal ions was proposed according to small-angle X-ray scattering (SAXS) and X-ray powder diffraction (XRD) measurements. Rheological measurements revealed that the mechanical strength of the hydrogels increased with increasing concentration of NaDC and Eu(NO3)3, while the maximum emission of the fluorescence of the gels appeared at a stoichiometry between Eu(NO3)3 and NaDC of 1:3. It is expected that the incorporation of luminescent lanthanide ions could impart versatile functionalities for practical applications to the hydrogels.

Synthesis and characterisation of a novel europium(iii)-containing heptaisobutyl-POSS

A novel Eu(iii)-containing POSS with good light quantum efficiency and high photostability was designed and characterized by a multidisciplinary approach.