POF-Based Solar Concentrators Incorporating Dyes and Europium Chelates

In this paper, useful models that enable time-efficient computational analyses of the performance of luminescent solar concentrators (LSCs) are developed and thoroughly described. These LSCs are based on polymer optical fibers codoped with organic dyes and/or europium chelates. The interest in such dopants lies in the availability of new dyes with higher quantum yields and in the photostability and suitable absorption and emission bands of europium chelates. Time-efficiency without compromising accuracy is especially important for the simulation of europium chelates, in which non-radiative energy transfers from the absorbing ligands to the europium ion and vice versa are so fast that the discretization in time, in the absence of some simplifying assumptions, would have to be very fine. Some available experimental results are also included for the sake of comparison.

Self-assembled luminescent cholate gels induced by a europium ion in deep eutectic solvents

Luminescent gels have been successfully fabricated through the self-assembly of sodium cholate and a europium ion in choline chloride-based deep eutectic solvents.

Synthesis and Characterization of Eu3+ + 2-thenoyltrifluoroacetone + triphenylphosphine Oxide Ternary Complex

Rare earth europium ion (Eu3+) can emit red characteristic fluorescence under UV excitation and is preferred for the preparation of red phosphors for near-UV white LEDs. In this paper, the effects of solvent, reflux time and preparation method on the preparation of europium ternary complexes were studied with europium ion as the central coordination ion, 2-thenoyltrifluoroacetone as the first ligand and triphenylphosphine oxide as the second ligand. The results showed that the better reaction solvent was anhydrous ethanol and the better reflux time was 8 hours. Both the common synthesis method and the solvothermal method could successfully synthesize the europium ternary complex, and the solvothermal method has a higher yield. The europium ternary complex was characterized by inductively coupled plasma emission spectroscopy, element analysis and infrared spectroscopy, and it was proved that the europium complex could emit a strong characteristic red fluorescence of europium with the structure of Eu(TTA)3(TPPO)2 in 1:3:2 coordination ratio.

Synthesis, Characterization, and Application of Europium(III) Complexes as Luminescent Markers of Banknotes

In this work, three complexes were synthesized from the trivalent europium ion (EuIII), using the picrate anion (pic), and delta-valerolactam (DVL), epsilon-caprolactam (EPK), and oenantholactam (OEN). The synthesized complexes [Eu(pic)3∙(DVL)3], [Eu(pic)3∙(EPK)3], and [Eu(pic)3∙(OEN)3] were studied as luminescent markers for application as security elements in Brazilian banknotes. All complexes showed red color emission with absorption at 397 nm and emission at 614 nm. Qualitative luminescence tests were performed on R$10, R$20, R$50, and R$100 Brazilian banknotes. The complexes were applied on the surface of the banknotes and were exposed to different wavelengths of 254, 312, 365, and 320-400 nm. The chemical profiles of the complexes were identified on the banknotes employing the laser desorption ionization mass spectrometry (LDI (±) MS) technique. Generally, tests were promising, and can thus provide a simple, fast, and easy method to identify the authenticity of questioned documents, with an average cost of R$0.65 per mg.

Solid–Liquid Europium Ion Extraction via Phosphonic Acid-Functionalized Polyvinylidene Fluoride Siloxanes

Novel triethoxysilane and dimethyl phosphonate functional vinylidene fluoride (VDF)-containing terpolymers, for potential applications in Eu ion extraction from water, were produced by conventional radical terpolymerization of VDF with vinyltriethoxylsilane (VTEOS) and vinyldimethylphosphonate (VDMP). Although initial attempts for the copolymerization of VTEOS and VDMP failed, the successful terpolymerization was initiated by peroxide to lead to multiple poly(VDF-ter-VDMP-ter-VTEOS) terpolymers, that had different molar percentages of VDF (70–90 mol.%), VTEOS (5–20 mol.%) and VDMP (10 mol.%) in 50–80% yields. The obtained terpolymers were characterized by 1H, 19F, 29Si and 31P NMR spectroscopies. The crosslinking of such resulting poly(VDF-ter-VDMP-ter-VTEOS) terpolymers was achieved by hydrolysis and condensation (sol–gel process) of the triethoxysilane groups in acidic media, to obtain a 3D network, which was analyzed by solid state 29Si and 31P NMR spectroscopies, TGA and DSC. The thermal stability of the terpolymers was moderately high (up to 300 °C under air), whereas they display a slight increase in their crystallinity-rate from 9.7% to 12.1% after crosslinking. Finally, the dimethyl phosphonate functions were hydrolyzed into phosphonic acid successfully, and the europium ion extraction capacity of terpolymer was studied. The results demonstrated a very high removal capacity of Eu(III) ions from water, up to a total removal at low concentrations.