Effect of solution pH value changes on fluorescence intensity of magnetic-luminescent Fe3O4@Gd2O3:Eu3+ nanoparticles

N-octylpyridine hydrogen sulphate ionic liquid for multifunctional fluorescent response in different solvents

Ionic liquids (ILs) have attracted considerable interest in the last two decades owing to their unique fluorescent properties. Herein, N-octylpyridine hydrogen sulphate ([OP]HSO4) was synthesised and characterised using 1H NMR and infrared spectroscopies. In addition, the fluorescence spectra of [OP]HSO4 in water, methanol, ethanol and acetonitrile were studied. In a single solvent, as the concentration of the solvent (methanol, ethanol or acetonitrile) increases, the fluorescence intensity of the IL first increases and then decreases. A similar trend was observed in their mixed solvents with water. Moreover, the fluorescence intensity of [OP]HSO4 decreases with increasing temperature. A fluorescence intensity reduction of only 4.46% for [OP]HSO4 after continuous scanning for 40 cycles under the maximum excitation state was analysed. The lack of photobleaching observed in [OP]HSO4 indicates its good photobleaching resistance.

Facile electrochemiluminescence sensing platform based on Gd2O3:Eu3+ nanocrystals for organophosphorus pesticides detection in vegetable samples

In this work, europium ion-doped gadolinium trioxide nanocrystals (Gd2O3:Eu3+ NCs) were successfully synthesized and applied to construct an electrochemiluminescence (ECL) sensor. Compared with pure Gd2O3, the doping of Eu3+ ions caused enhanced ECL intensity and more stable signals. Based on the excellent ECL performance of Gd2O3:Eu3+ NCs, we constructed a new ECL sensing platform for the detection of organophosphorus pesticides (OPs). The ECL sensor showed a good linear relationship in the concentration range of 1 nM to 1 pM, with a limit of detection of 0.12 pM (S/N = 3) for dichlorvos (DDVP). In addition, the constructed ECL sensor was applied for the detection of DDVP in vegetable samples, and good recoveries were obtained. The results indicated that the ECL sensor exhibited fantastic performance properties and had good application prospects in OPs detection.

Improvement of Magnetic Saturation in Fe3O4@Y2O3:Eu3+ Nanocomposites Through the Manipulation of Eu3+ Activators

Fe3O4@Y2O3:Eu3+ nanocomposites and Y2O3:Eu3+ nanophosphors were synthesized using the hydrothermal method. Nanocomposites were analyzed using X-ray diffraction (XRD), Rietveld refinements, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, photoluminescence (PL), vibrating sample magnetometer (VSM), and high-resolution transmission electron microscopy (HRTEM). Nanocomposites exhibit superparamagnetic behavior that improves with Eu3+, resulting in increased magnetic saturation. In contrast to Y2O3:Eu3+ nanophosphors, the Fe3O4@Y2O3:Eu3+ nanocomposites display a distinctive characteristic whereby the photoluminescence intensity increases with a reduced concentration of Eu3+. The requirement of increasing the thickness of the Y2O3:Eu3+ outer layer to achieve improved light emission can be circumvented by solely manipulating the concentration of activators, without compromising the magnetic saturation of the nanocomposites. The luminescent and magnetic characteristics of Fe3O4@Y2O3:Eu3+ nanocomposites can be readily optimized using straightforward synthesis parameters, making them promising candidates for potential applications in theranostic medicine.

Fe2O3 Nanoparticles Doped with Gd: Phase Transformations as a Result of Thermal Annealing

The aim of this work is to study the effect of the phase composition of the synthesized Fe2O3-Gd2O3 nanoparticles on the efficiency of using magnetic hyperthermia as a basis for experiments. This class of structures is one of the most promising materials for biomedical applications and magnetic resonance imaging. In the course of the study, the dynamics of phase transformations of nanoparticles Fe2O3 → Fe2O3/GdFeO3 → GdFeO3 were established depending on the annealing temperature. It has been determined that the predominance of the GdFeO3 phase in the structure of nanoparticles leads to an increase in their size from 15 to 40 nm. However, during experiments to determine the resistance to degradation and corrosion, it was found that GdFeO3 nanoparticles have the highest corrosion resistance. During the hyperthermal tests, it was found that a change in the phase composition of nanoparticles, as well as their size, leads to an increase in the heating rate of nanoparticles, which can be further used for practical purposes.

HSA functionalized Gd2O3:Eu3+ nanoparticles as an MRI contrast agent and a potential luminescent probe for Fe3+, Cr3+, and Cu2+ detection in water

PVP capped Gd₂O₃:Eu³⁺ (PVP@Gd₂O₃:Eu³⁺) and HSA functionalised PVP@Gd₂O₃:Eu³⁺ (HSA@PVP@Gd₂O₃:Eu³⁺) NPs as fluorescent detection probe for metal ion detection and MRI contrast agent.

Magnetic, structural and cation distribution studies on [Formula: see text] (x = 0.00, 0.02, 0.04, 0.06 and 0.1) nanoparticles

We synthesized and characterized the colloidal suspensions of [Formula: see text] nanoparticles with x = 0.00, 0.02, 0.04, 0.06 and 0.1. The effect of the Fe³⁺ ion replacement by Nd³⁺ on the crystal structure is in-depth studied. The samples were characterized by the following techniques: X-ray diffraction (XRD), UV-Vis spectrophotometry, transmission electronic microscopy (TEM), small-angle X-ray scattering (SAXS), magnetization as a function of applied magnetic field (M-H loops) and magnetization as a function of temperature in zero-field-cooled and field-cooled regimes (ZFC-FC). From XRD cation distribution, structural parameters were extracted. The increasing in the bandgap is interpreted as a result of the higher interatomic separation with the doping. TEM micrographs reveal a polydisperse size and shape distribution of particles. The results for the volume-weighted average diameter measured by SAXS are consistent with those determined by XRD. From the M-H loops we found that the superparamagnetic (SPM) regime contributes with 95-97% for all samples, while only 3-5% contribution comes from the paramagnetic (PM) regime. The saturation magnetization increases in a steady manner upon increasing the Nd³⁺ ion molar ratio from 0.00 up to 0.06, reaching the maximum value of 105.8±0.4 Am²/kg at x = 0.06. It is worth to mention that the result for the saturation magnetization value are higher than that of the bulk material.

Preparation and characterization of nanosphere and nanorod Gd2O3:Tb3+ by polyol route

Nanorod and nanosphere ${{\rm Gd}_2}{{\rm O}_3}\!:\!{{\rm Tb}^{3 + }}$Gd₂O₃:Tb³⁺ particles were synthesized from chloride precursors ${{\rm GdCl}_3}$GdCl₃ and ${{\rm TbCl}_3}$TbCl₃ by NaOH addition in a diethylene glycol medium. The nanospheres and the nanorods of ${{\rm Gd}_2}{{\rm O}_3}\!:\!{{\rm Tb}^{3 + }}$Gd₂O₃:Tb³⁺ were tunably obtained by adjusting the addition speed of NaOH. The structure, morphologies, and the luminescence properties of nanorod and nanosphere ${{\rm Gd}_2}{{\rm O}_3}\!:\!{{\rm Tb}^{3 + }}$Gd₂O₃:Tb³⁺ were characterized by x-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and fluorescence spectrometry, respectively. The results confirmed that the structure of nanorod and nanosphere ${{\rm Gd}_2}{{\rm O}_3}\!:\!{{\rm Tb}^{3 + }}$Gd₂O₃:Tb³⁺ is cubic ${{\rm Gd}_2}{{\rm O}_3}$Gd₂O₃, and the luminescence of nanospheres is more intense than that of nanorods. The low cytotoxicity measured by the MTT method indicated the good biocompatibility of the samples.

Flexible sandwich-shaped composite film with simultaneous double electrically conductive anisotropy, magnetism and dual-color fluorescence

Flexible sandwich-shaped composite film with simultaneous double electrically conductive anisotropy, magnetism and dual-color fluorescence was successfully constructed via electrospinning.

Enhancing the Magnetic–Luminescent Properties of Fe3O4@Y2O3:Eu3+ Core–Shell Bifunctional Particles Using Li+ Doping

Magnetic–luminescent nanoparticles are now attracting great attention in biochemistry and biomedicine for their promising bifunctional characteristics. In this work, we propose a strategy of Li+ doping to enhance both the luminescent and magnetic properties of Fe3O4@Y2O3:Eu3+ core–shell particles. A comprehensive investigation of phase assembly, microscopic morphology, luminescence, and magnetic characteristics of the bifunctional particles was carried out. The core–shell structured particles have a spherical morphology and the agglomerated particle size is ~1 μm in diameter. Under 254 nm excitation, the co-doped sample (5 mol-% Li+) with a dominant emission peak at 612 nm, exhibits luminescence 2.35 times more intense than the undoped sample (0 mol-% Li+). Li+ doping also leads to an improved saturation magnetisation, which was 2.41 times greater than the undoped sample.