Structure, Luminescence, and Dynamics of Eu2O3 Nanoparticles in MCM-41

Exceptionally high proton conductivity in Eu2O3 by proton-coupled electron transfer mechanism

Proton conductors are typically developed by doping to introduce structural defects such as oxygen vacancies to facilitate ionic transport through structural bulk conduction mechanism. In this study, we present a novel electrochemical proton injection method via an in situ fuel cell process, demonstrating proton conduction in europium oxide (Eu2O3) through a surficial conduction mechanism for the first time. By tuning Eu2O3 into a protonated form, H-Eu2O3, we achieved an exceptionally high proton conductivity of 0.16 S cm-1. Distribution of relaxation time (DRT) analysis was employed to investigate the proton transport behavior and reveal the significant contribution of surface proton transport to the overall conductivity of Eu2O3. Remarkably, H-Eu2O3 exhibited a low activation energy for ionic transport, comparable to the best ceramic electrolytes available. The proton-coupled electron transfer (PCET) mechanism describes this novel surficial proton conduction mechanism. These findings provide new possibilities for developing advanced proton conductors with improved performance.

A highly selective optical sensor Eu-BINAM for assessment of high sensitivity cardiac troponin tumor marker in serum of cancer patients

A novel, easy, touchy and selective spectrofluorimetric technique has been successfully applied for sensitive determination of High Sensitivity Cardiac Troponin (TNHS I) in the serum samples of patients suffering malignant tumors through the usage of optical sensor Eu^3+-BINAM complex. The technique is primarily based on quenching of the Eu³⁺-BINAM complex's luminescence intensity upon introducing various concentrations of High Sensitivity Cardiac Troponin (TNHS I). The synthesis and characterization of the optical sensor was performed via absorption and emission. The sensor was also adapted to offer excitation at 394 nm in acetonitrile at pH 7.5. Concentration of High Sensitivity Cardiac Troponin (TNHS I) in serum samples was found to be proportional to the luminescence intensity quenching of the Eu³⁺-BINAM complex, most prominently at λ_em = 618 nm. The limit of the dynamic range is 4.26 × 10^-4 to 2 ng/mL. The limit of detection and quantitation were calculated to be 1.35 and 4.10 ng/mL, respectively. The suggested analytical approach proved its applicability, simplicity and comparatively interference- free. The technique was effectively recruited to quantify High Sensitivity Cardiac Troponin (TNHS I) in human serum samples. The proposed technique could be further extended to evaluate some biomarkers associated with malignancy related diseases in human.

Molecular docking study on europium nanoparticles and mussel adhesive protein for effective detection of latent fingerprints

Background: Reflecting on the difficulty of finding the evidence of latent fingerprints on wet and rough surfaces, scientists need to visualise those fingermarks without any background interference and stable adhesion of visualising material over the fingermark residues.Objective: To stabilize the interaction with the fingermarks, the synthesized nanoparticles were conjugated with a highly adhesive biopolymer, Mussel Adhesive Protein (MAP) which can effectively interact with fingerprint deposits.Material and Methods: Rare earth metal, europium oxide and nanoparticles were used as a visualisation material to get high contrast and reduced background interference-based fingerprints. To stabilise the interaction with the fingermarks, the synthesised nanoparticles were conjugated with highly adhesive biopolymer, Mussel Adhesive Protein (MAP) which can effectively interacts with fingerprint deposits. A molecular docking study was done using Auto-Dock to find the binding affinity between the metal nanoparticle and the protein. Further, the stability of the bioconjugated with fingerprint residues was analysed by protein-protein interaction study through patch dock and PDB Sum.Results: The docking analysis between europium and nanoparticles with MAP was found to be -8.77 kcal/mol and -47.49 kcal/mol respectively. Protein-protein interaction studies showed a highest affinity for dermcidin and keratin with a binding affinity of -16.76 kcal/mol and -24.76 kcal/mol respectively.Conclusions: The docking studies showed an efficient interaction between the synthesised molecules and the fingermark residues. Results of these interaction studies proved that this bio-conjugated complex can be explored for efficient visualisation of low intensified fingermarks.

Ultrasmall Downconverting Nanoparticle for Enhanced Cerenkov Imaging

Cerenkov imaging provides an opportunity to expand the application of approved radiotracers and therapeutic agents by utilizing them for optical approaches, which opens new avenues for nuclear imaging. The dominating Cerenkov radiation is in the UV/blue region, where it is readily absorbed by human tissue, reducing its utility in vivo. To solve this problem, we propose a strategy to shift Cerenkov light to the more penetrative red-light region through the use of a fluorescent down-conversion technique, based upon europium oxide nanoparticles. We synthesized square-shape ultrasmall Eu₂O₃ nanoparticles, functionalized with polyethylene glycol and chelate-free radiolabeled for intravenous injection into mice to visualize the lymph node and tumor. By adding trimethylamine N-oxide during the synthesis, we significantly increased the brightness of the particle and synthesized the (to-date) smallest radiolabeled europium-based nanoparticle. These features allow for the exploration of Eu₂O₃ nanoparticles as a preclinical cancer diagnosis platform with multimodal imaging capability.

Optical properties of biosynthesized nanoscaled Eu2O3 for red luminescence applications

This contribution reports on the optical properties of biosynthesised Eu₂O₃ nanoparticles bioengineered for the first time by a green and cost effective method using aqueous fruit extracts of Hyphaene thebaica as an effective chelating and capping agent. The morphological, structural, and optical properties of the samples annealed at 500°C were confirmed by using a high-resolution transmission electron microscope (HR-TEM), x-ray diffraction analysis (XRD), UV-Vis spectrocopy, and photoluminescence spectrometer. The XRD results confirmed the characteristic body-centered cubic (bcc) structure of Eu₂O₃ nanoparticles with an average size of 20 nm. HR-TEM revealed square type morphology with an average size of ∼6nm. Electron dispersion energy dispersive x-ray spectroscopy spectrum confirmed the elemental single phase nature of pure Eu₂O₃. Furthuremore, the Fourier transformed infrared spectroscopy revealed the intrinsic characteristic peaks of Eu-O bond stretching vibrations. UV-Vis reflectance proved that Eu₂O₃ absorbs in a wide range of the solar spectrum from the VUV-UV region with a bandgap of 5.1 eV. The luminescence properties of such cubic structures were characterized by an intense red emission centered at 614 nm. It was observed that the biosynthesized Eu₂O₃ nanoparticles exhibit an efficient red-luminescence and hence a potential material as red phosphor.

Spectroscopic Studies of Mössbauer, Infrared, and Laser-Induced Luminescence for Classifying Rare-Earth Minerals Enriched in Iron-Rich Deposits

Rare-earth (RE) phosphates often appear as an accessory phase in igneous or metamorphic rocks; however, these rocks are composed of myriad chemical elements and nuclides that interfere with the qualitative or quantitative analyses of the RE phosphates over a range of concentrations in the absence of a pretreatment. In addition, the limit of each analytical methodology constrains the approach as well as the usefulness of the results in geoscience applications. Here, we report the specific mineral characterization of RE-containing ores from Yen Phu mine, Vietnam, using a range of state-of-the-art spectroscopic techniques in conjunction with microscopy: Mössbauer spectroscopy, infrared microspectroscopy, time-resolved laser-induced fluorescence spectroscopy (TRLFS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Because the distribution of each element in the deposit differs, such combinatorial works are necessary and could lead to more plausible answers to questions surrounding the point of origin of RE elements. The results of our Mössbauer spectroscopic analysis indicate that the three ores sampled at different locations all contain magnetite-like, hematite-like, and iron(III) salts other than hematite. In addition, we confirmed the presence of phosphate around the grain boundary in the magnetite-like mineral phase by infrared microspectroscopic analysis. The present analytical findings of trace amounts of europium(III) using TRLFS suggest that the europium ions generate identical luminescence spectra despite being embedded in three different matrices of iron minerals. This demonstration highlights the benefits of combinatorial spectroscopic analyses to gain insights into the effects of the environment of REs on their solid-state chemistry and shows the potential utility of TRLFS as a resource mining tool. Further applications of this approach in the analytical screening of rocks and minerals are feasible.

Optimization of Eu3+ Luminescence in DMSO as a Multiparameter Method for Trace Water Detection

Photoluminescence of Eu3+ in DMSO is intense and ultrasensitive to water, thereby providing a novel method for water detection. Herein, for the first time, we investigated the effects of Eu3+ concentration on luminescence and developed a multiparameter method for trace water detection based on a single luminescence agent. To further extend its practical applications, we explored its performance for water detection in ethanol and gasoline. Our findings demonstrate that it is a sensitive and reliable probe for the detection of a wide concentration range of water in ethanol (0-24.24%) and gasoline (0-32.43%), making Eu-DMSO a promising candidate to detect water in a wide concentration range. These phenomena not only make Eu-DMSO a sensitive agent for in situ water detection in real time but also provide scientifically interesting mechanisms behind its application as a water sensing probe.

Hydrothermal synthesis of 4ZnO·B2O3·H2O:Ln3+ (Ln=Eu, Tb) phosphors: Morphology-tunable and luminescence properties

4ZnO·B₂O₃·H₂O:Ln³⁺ (Ln=Eu, Tb) phosphors with different morphologies have been successfully synthesized via one-step hydrothermal method through regulating the molar amount of Eu³⁺ and Tb³⁺. Comprehensive scanning electron microscopy (SEM), X-ray diffraction (XRD) Fourier transform infrared spectrum (FT-IR) and inductively coupled plasma atomic emission spectrometer (ICP-AES) characterizations all confirm that obtained products are 4ZnO·B₂O₃·H₂O:Ln³⁺ (Ln=Eu, Tb). The experimental results displayed that the morphology and photoluminescence of compounds is regularly changed with increased the molar amount of rare earth ions. For the Eu³⁺-doped, Tb³⁺-doped and Eu³⁺/Tb³⁺ co-doped 4ZnO·B₂O₃·H₂O phosphors of morphologies, the rod-like structures gradually changed to flower-like structures, fine wire-like structure and hybrid structure, respectively. To their photoluminescence, the Eu³⁺ shows a red emission (615nm); the Tb³⁺ shows a green emission (545nm); for the Eu³⁺/Tb³⁺ co-doped 4ZnO·B₂O₃·H₂O phosphors, a combination of blue (5d-4f of Eu²⁺), green (⁵D₄-⁷F₅ of Tb³⁺) and red (⁵D₀-⁷F₂ of Eu³⁺) emissions emerges to achieve white emission. In addition, the energy transfer among Eu³⁺, Eu²⁺ and Tb³⁺ ions was also discussed.

Green and blue emitting 3D structured Tb:Ce2(WO4)3and Tb:Ce10W22O81micromaterials

Various Ce₂(WO₄)₃and Ce₁₀W₂₂O₈₁3D microstructures prepared hydrothermally in the absence and presence of a surfactant are reported. The different luminescence properties of the two types of materials, when doped with Tb³⁺ions were investigated and appropriate energy transfer mechanisms are suggested.

Synthesis, characterization and luminescent properties of new highly luminescent organic ligand and complexes of trivalent rare earth

A novel ligand with two carboxylic groups has been synthesized. The composition and structure of the ligand were characterized by IR, (1)H NMR and MS spectrometry. The highly luminescent intensity complexes were prepared with the ligand and phen. The IR, solid state (13)C NMR and fluorescent spectra of the complex were studied. IR absorption spectra indicate that the ligand is coordinated to the Eu(3+) ion, and chemical bonds are formed between Eu(3+) ion and nitrogen atoms of phen. The fluorescent spectra illustrate that the complex has an excellent luminescence, indicating the ligand favors energy transfer to the emitting energy level of Eu(3+). The influences of pH and reaction solvent on the fluorescence intensity of the complex were also discussed.

Preparation, Characterization, and Condensation of Copper Tellurolate Clusters in the Pores of Periodic Mesoporous Silica MCM-41

The copper-tellurolate cluster [(Cu(6)(TePh)(6)(PPh(2)Et)(5)] has been loaded into the pores of MCM-41 by solid-state impregnation techniques. It was found that the best loading conditions are 110 degrees C and 10(-)(3) Torr static vacuum. The resulting material was analyzed by powder X-ray diffraction (PXRD), nitrogen adsorption isotherms, thermogravimetric analysis (TGA), (31)P CP MAS NMR spectroscopy, and TEM. It was observed that loading is accompanied by loss of the phosphine shell, with retention of the copper-tellurium core. Condensation of the impregnated material may proceed thermally or photochemically. Thermal condensation results in the formation of Cu(2)Te nanoparticles as demonstrated by PXRD, and TEM data suggests that the process has taken place inside the pores of MCM-41. Photochemical condensation yields larger metal-chalcogen clusters in the pores as suggested by the result of UV-vis diffuse reflectance spectroscopy and TEM measurements.