Gd 2O3 Research Articles

Study on the photoluminescence performance and thermal sensitivity of (Y,Gd)2O3:Tb3+,Dy3+,Tm3+ phosphors

Using ammonia as a precipitation agent, (Y,Gd)2O3:Tb3+x,Dy3+y,Tm3+z phosphors were synthesized by the co-precipitation method. In order to improve the luminescence performance of the luminescent center Tb3+, Tb3+-Dy3+ co-doping and Tb3+-Dy3+-Tm3+ tri-doping were successively carried out, and the optimal component formulations were determined by the controlled variable method (x = 0.03, y = 0.005, z = 0.001). XRD results showed that the sample has a cubic phase Y2O3 structure with good crystalline properties. SEM results revealed that the samples have a unique micro morphology of small ball aggregation. The effects of doping concentration of Dy3+ and Tm3+ on the luminescence properties of Tb3+ were systematically investigated. The energy transfer mechanism among the three ions of Tb3+-Dy3+-Tm3+ was demonstrated by photoluminescence spectroscopy, and the main interaction modes between ions were elucidated. In addition, the matrix lattice environment can change the thermal stability properties of phosphors. In this paper, the temperature characteristics of Y2O3:Tb3+,Dy3+,Tm3+ phosphors are expected to be changed by microtuning the Y2O3 matrix lattice with the introduction of Gd3+. The fluorescence intensity ratio (FIR) and thermal sensitivity indicated that Gd3+ has good temperature sensitivity, and its introduction can effectively improve the temperature sensing performance of the phosphors, which has a wide range of applications in optical temperature measurement sensors.

Synthesis and multifunctional characterizations of Gd2 O3 and Sm2 O3 modified ZnO nanoparticles

In the present communication multifunctional characterizations suitable for spintronics and memory storage devices are described. Double doped (Gd3+, Sm3+) ZnO nanoparticles are prepared from Sol-Gel method using poly vinyl alcohol (PVA) as chelating agent. The as prepared powders are annealed at 500 °C–1000 °C with a step size of 100 °C. The genesis of single phase hexagonal wurtzite structure, morphological and topographical changes, optical, magnetic and mechanical properties were studied with XRD (X-ray diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy dispersive spectroscopy), UV- DRS (ultraviolet diffuse reflective spectroscopy), PL (photoluminescence), VSM (vibrating sample magnetometer) and pin on disc tribometer. XRD study untangled the crystallite size and found to be in the range23-50nm. Polycrystalline nanoparticles of spherical geometry with induced porosity is observed from SEM study. The particle size associated with the samples annealed at 500 °C and 900 °C is 24 nm and 27 nm respectively from TEM study. Analyzed the proximity of functional groups, molecular vibrations in the range of 400-4000 cm−1 employing FTIR (Fourier transform infrared spectroscopy). EDS results revealed the stoichiometry of the produced samples. The pronounced optoelectronic applications of Zn1-x Gdx Smx O (ZGS) can be attributed to the large band gap (3.50–3.02 eV) associated with the materials with rise in annealing temperature. The room temperature ferromagnetism was evidenced with double doped ZnO nanomaterials. The wear coefficient, and friction coefficient were evaluated using pin-on-disc tribometer. The utility of materials as solid state lubricants was confiscated from the range of frictional coefficient values (0.067–0.893).

Polyoxometalate Induced Assembly Into Surface Functionalized Multidimensional Heterostructures with Enhanced Catalytic Activity.

The self-assembly of inorganic nanocrystals offers an efficient way for the fabrication of functional materials. However, it is still challenging for the construction of multidimensional nanostructures with controllable shapes, compositions and functions. Here, a series of heterostructures in different dimensions by surface modification of polyoxometalate (POM) clusters is developed. Three kinds of POM clusters(phosphomolybdic acid (PMA), phosphotungstic acid (PTA) and silicotungstic acid (STA) and five kinds of metal oxides (TiO2 , VOx , La2 O3 , In2 O3 and Gd2 O3 ) can be used as building blocks, and a class of 1D, 2D and 3D heterostructures can be achieved by the control of surface ligand coverage. Compared with individual building blocks and other cluster-based superstructures, TiO2 -PMA superstructures exhibit enhanced catalytic activity toward thioether oxidations, which is attributed to the electron transfer between TiO2 and POM clusters.

Effects of Gd3+-doping on the fabrication and performances of highly transparent (Lu,Gd)2O3:Eu solid-solution ceramics

By pre-treating and component design of the ceramic powders, cubic (Lu,Gd)2O3:Eu solid-solution ceramics with high optical quality were achieved by the solid-state reaction method combined with vacuum sintering. The effects of Gd3+ doping (x = 0.05–0.6) on powder characteristics, phase compositions, microstructures and optical performances of the (Lu0.95-xGdxEu0.05)2O3 ceramics were systematically investigated to obtain the optimum Gd3+ content. The results indicated that the incorporation of moderate amounts of Gd3+ (5–50 mol%) effectively promoted mass diffusion and grain growth during sintering. The 50 mol% Gd3+-doped Lu2O3:Eu transparent ceramic (using the powder calcined at 1200 °C) sintered at 1750 °C for 5 h exhibited the optimum transmittance of 77.0 % in the visible spectral region (∼1 mm in thickness), which was significantly higher than the reported transmittance of vacuum sintered (Lu,Gd)2O3:Eu ceramics (less than 65.0 %). Owing to the lower electronegativity of Gd3+ relative to Lu3+, the bandgap energies of the final ceramics decreased gradually with increasing Gd3+ substitution, and the redshift of the CTB centre was observed with more Gd3+ addition. Under CTB excitation, the incorporation of Gd3+ enhanced the red emission intensity and shortened the fluorescence lifetime.

Photo- and cathodo-luminescence properties of (Lu, Gd)2O3: Ce3+, Tb3+ phosphors prepared by sol–gel method

Photo- and cathodo-luminescence properties of (Lu, Gd)2O3: Ce3+, Tb3+ phosphors prepared by sol–gel method

Leveraging 3D Bioprinting and Photon-Counting Computed Tomography to Enable Noninvasive Quantitative Tracking of Multifunctional Tissue Engineered Constructs.

3D bioprinting is revolutionizing the fields of personalized and precision medicine by enabling the manufacturing of bioartificial implants that recapitulate the structural and functional characteristics of native tissues. However, the lack of quantitative and noninvasive techniques to longitudinally track the function of implants has hampered clinical applications of bioprinted scaffolds. In this study, multimaterial 3D bioprinting, engineered nanoparticles (NPs), and spectral photon-counting computed tomography (PCCT) technologies are integrated for the aim of developing a new precision medicine approach to custom-engineer scaffolds with traceability. Multiple CT-visible hydrogel-based bioinks, containing distinct molecular (iodine and gadolinium) and NP (iodine-loaded liposome, gold, methacrylated gold (AuMA), and Gd2 O3 ) contrast agents, are used to bioprint scaffolds with varying geometries at adequate fidelity levels. In vitro release studies, together with printing fidelity, mechanical, and biocompatibility tests identified AuMA and Gd2 O3 NPs as optimal reagents to track bioprinted constructs. Spectral PCCT imaging of scaffolds in vitro and subcutaneous implants in mice enabled noninvasive material discrimination and contrast agent quantification. Together, these results establish a novel theranostic platform with high precision, tunability, throughput, and reproducibility and open new prospects for a broad range of applications in the field of precision and personalized regenerative medicine.

Janus Dual Self-Strengthening Structure of Bi2 O3 /Gd2 O3 Nanofibrous Membranes for Superior X-Ray Shielding.

Bi2 O3 /rare earth oxide biphasic absorbers are attractive for high-efficiency X-ray shielding due to the complementary X-ray absorption effects. However, its application is severely hindered by poor interphasic contact. Here, a new Janus interface engineering strategy is reported for the construction of continuous and flexible Bi2 O3 /Gd2 O3 crystal nanofibrous membranes (FJNMs) with micro/nano dual self-strengthening interphasic adhesion. This strategy facilitates online micro-interlocking between Bi2 O3 /Gd2 O3 nanofibers and in situ nano-grain fusion between Bi2 O3 /Gd2 O3 crystals, significantly enhancing the adhesive strength at the Bi2 O3 /Gd2 O3 interface. Additionally, the synergistic shielding effect from Bi2 O3 /Gd2 O3 absorption and multiple reflections in Bi2 O3 and Gd2 O3 crystal lattices make the nanofibrous membranes a superior X-ray radiation barrier. The FJNMs demonstrate integrated features of exceptional X-ray shielding efficiency (91%-100%), robust interfacial adhesion (lap-shear strength >3.8MPa), prominent flexibility, lightweight, and outstanding breathability. The design concepts of fibrosing biphasic absorber assemblies pave the way for asymmetrically assembling biphasic materials, setting the stage for a fundamental shift in next-generation radiation shielding materials.

Nanoparticle-Based MRI-Guided Tumor Microenvironment Heating via the Synergistic Effect of Ferroptosis and Inhibition of TGF-β Signaling.

Although induction of ferroptosis and inhibition of transforming growth factor-β (TGF-β) signaling are both effective ways to reform the tumor microenvironment (TME) and render low-immunogenic tumors responsive to immune checkpoint inhibitor (ICI) therapy, dose-limiting side effects remain major obstacles hindering their clinical application. Herein, a novel sorafenib and anti-TGF-β antibody loaded Fe3 O4 /Gd2 O3 hybrid nanoparticles with conjugation of RGD dimer (FeGd-HN@Sorafenib@TGF-β-antibody@RGD2, FG-STR) is developed. Sorafenib significantly enhances FeGd-HN-triggered ferroptosis and improves maturation and phagocytosis of dendritic cells (DCs) by inducing damage-associated molecular patterns released from ferroptotic cancer cells, while the anti-TGF-β antibody further synergizes with enhanced ferroptosis to promote DC maturation and the recruitment of CD8+ T cells, thus heating the TME. Moreover, incorporation of RGD2 facilitates uptake of the FG-STR in tumor cells which led to a significant dosage reduction of both sorafenib and anti-TGF-β antibody to avoid dose-limiting toxicities. Finally, in vitro and in vivo experiments shows that FG-STR has significantly superior intrinsic magnetic resonance imaging (MRI) capability than that of Gadovist, effectively inhibits tumor growth and lung metastasis, and increased the efficacy of anti-programmed cell death-1 treatment. Taken together, this study provides a promising strategy for new advanced MRI-guided TME heating therapies. This article is protected by copyright. All rights reserved.

Effects of Zr4+-doping on the properties of (Lu, Gd)2O3: Eu transparent ceramics: Insight from the photoluminescent spectra in as-sintered and annealed state

We show the effects of the Zr4+-doping on the microstructural, optical, and luminescent properties of (Lu, Gd)2O3: Eu transparent ceramics in its as-sintered state and annealed state. Zr4+-dopant greatly enhanced the transparency of (Lu, Gd)2O3: Eu ceramic, giving Lu0.42Gd0.5Zr0.03Eu0.05O1.5+δ ceramic with a transmittance of up to 80% at 600 nm. It is found that Zr4+-dopant dominates the luminescent properties of Eu ions in both as-sintered and annealed ceramics. Energy transfer from Eu2+ to Eu3+ was found by photoluminescence spectra, and the ratio of Eu2+/(Eu2++Eu3+) was affected by Zr4+ content in as-sintered ceramics. Moreover, the oxygen vacancy concentration increased with increasing Zr4+ content in as-sintered ceramics. The annealing process enhanced the intensity of all the excitation bands of 4f→4f transitions and the intensity of charge transfer band (CTB) decreased as the Zr4+ content increased in the annealed ceramics. This work highlights that Zr4+ doping is a potential way to improve the transmittance and red emission intensity of 4f→4f transition of Eu3+ in the (Lu, Gd)2O3: Eu ceramic for extended applications.

The Use of a Suspension of Functionalized Gadolinium Oxide Nanoparticles for Photocatalytic Applications

Photo-degradation of Rhodamine B (RhB) in aqueous solution was use as a probe to assess the photocatalytic activity of Gadolinium oxide (Gd2 O3 ) nanoparticles in suspension under UV irradiation. The nanoparticles in suspension were prepared by a polyol method using gadolinium chloride hexahydrate (Gd2 Cl6 .6H2 O) and diethylene glycol (DEG) as starting precursors. The physico-chemical properties of the elaborated suspension are analyzed using X-ray diffraction (XRD), ultraviolet visible (UV-vis) and infrared (FTIR) spectroscopies, transmission electron microscopy (TEM) and viscosimetry. The Gd2 O3 nanoparticles in suspension were used as photocatalyst for the degradation of Rhodamine B (RhB) dye under irradiation with UV light. The results of the kinetic studies showed that the photodegradation reactions were followed by a pseudo first order reaction rate law over the first 30 minutes of monitoring. The elaborated Gd2 O3 nanoparticles suspension showed a great efficiency in the photocatalytic test without any addition of a co-catalyst, thus limiting the complexity of the further decontamination process of waste water.

Review of ceramic materials and recent development of preparation methods

Ceramics globally has been developed by various materials and methods to find suitable ceramics for specific applications. This paper discusses development of several methods in ceramic preparation such as hot-pressing, sintering, co-precipitation, and solid-state method. In 2001 up to 2019, hot-pressing method was used to manufacture ceramic B4C and SiAlCO as raw material doping by (W, Ti)C. In 2002 up to 2018 sintering method by using fly ash as raw material with an additional K2CO3, Na2CO3, and Nb2O5. In 2008, co-precipitation method was used for CaCu3Ti4O12 (CCTO) as raw material until 2019, and then ZrO2-Al2O3 as a newcomer ceramic material. From 2001 up to 2017, solid-state method was used with microwave for MgTiO and 3-CaTiO with Eu and (Lu, Gd) 2O3 as a dopant. This paper provided four methods and the materials from reported references from 2000 up to now, as guidance in producing specific functional ceramics in the future.

Modulating Nanozyme-Based Nanomachines via Microenvironmental Feedback for Differential Photothermal Therapy of Orthotopic Gliomas.

Gliomas are common and refractory primary tumors closely associated with the fine structures of the brain. Photothermal therapy (PTT) has recently shown promise as an effective treatment for gliomas. However, nonspecific accumulation of photothermal agents may affect adjacent normal brain structures, and the inflammatory response induced during PTT may result in an increased risk of brain tumor recurrence or metastasis. Here, the design and fabrication of an intelligent nanomachine is reported based on Gd2 O3 @Ir/TMB-RVG29 (G@IT-R) hybrid nanomaterials. These nanomaterials enable tumor-specific PTT and eliminate inflammation to protect normal brain tissue. The mechanism involves the rabies virus glycopeptide-29 peptide (RVG29) passing through the blood-brain barrier (BBB) and targeting gliomas. In the tumor microenvironment, Ir nanozymes can act as logic control systems to trigger chromogenic reaction amplification of 3,3',5,5'-tetramethylbenzidine (TMB) for tumor-specific PTT, whereas in normal brain tissues, they scavenge reactive oxygen species (ROS) generated by poor therapy and function as protective agents. Autophagy inhibition of Gd2 O3 enables excellent photothermal therapeutic effects on orthotopic gliomas and protection against inflammation in normal cells. The results of this study may prove useful in developing highly efficient nanomedicines for glioma treatment.

Cycloacceleration of Reactive Oxygen Species Generation Based on Exceedingly Small Magnetic Iron Oxide Nanoparticles for Tumor Ferroptosis Therapy.

Because of the insufficiency of hydrogen peroxide, the relatively low rate of Fenton reaction, and the active glutathione (GSH) peroxidase 4 (GPX4) in tumor cells, it is difficult to achieve a desirable efficacy of ferroptosis therapy (FT) for tumors based on nanomaterials. Inspired by the concept of "cyclotron" in physics, in this study, a new concept of cycloacceleration of reactive oxygen species (ROS) generation in tumor cells to realize high-performance FT of tumors is proposed. Typically, a magnetic resonance imaging (MRI) contrast agent of dotted core-shell Fe3 O4 /Gd2 O3 hybrid nanoparticles (FGNPs) is prepared based on exceedingly small magnetic iron oxide nanoparticles (ES-MIONs). Sorafenib (SFN) is loaded and poly(ethylene glycol) methyl ether-poly(propylene sulfide)-NH2 (mPEG-PPS-NH2 ) is grafted on the surface of FGNP to generate SA-SFN-FGNP via self-assembly. The results of in vitro and in vivo demonstrate SA-SFN-FGNP can work with the acidic tumor microenvironment and endosomal conditions, Fenton reaction and system XC - , and generate cyclic reactions in tumor cells, resulting in specific cycloacceleration of ROS generation for high-performance FT of tumors. The very high longitudinal relaxivity (r1 , 33.43 mM-1 s-1 , 3.0 T) makes sure that the SA-SFN-FGNP can be used for MRI-guided FT of tumors.

Mass spectrometric study and modeling of the thermodynamic properties in the Gd2 O3 -ZrO2 -HfO2 system at high temperatures.

Materials based on the Gd2 O3 -ZrO2 -HfO2 system are promising for a wide range of high-temperature technological applications, such as for obtaining thermal barrier coatings in the aviation and space industry, as well as advanced materials in nuclear power applications. Experimental studies of the ceramics based on this system by the Knudsen effusion mass spectrometric method provides such valuable information as the vapor composition over the samples and enables derivation of the thermodynamic functions. Samples of ceramics in the Gd2 O3 -ZrO2 -HfO2 system were synthesized and analyzed by X-ray fluorescence and diffraction techniques. The vaporization processes and partial pressures of the vapor species over the samples were obtained by the high-temperature mass spectrometric method using the ion current comparison method. The derived thermodynamic functions were optimized within the Generalized Lattice Theory of Associated Solutions (GLTAS) approach. At the temperature of 2600 K, the GdO, ZrO, ZrO2 , HfO, and O vapor species were found over the samples, but only for the GdO and ZrO species were accurate experimental data on the partial pressures obtained. In all the ceramic samples, the Gd2 O3 activity was determined. On this experimental basis, modeling within the GLTAS approach was performed. It allowed the evaluation of the Gd2 O3 , ZrO2 , and HfO2 activities in the system under study and a rough approximation of the excess Gibbs energy as a function of composition to be obtained. At 2600 K the Gd2 O3 -ZrO2 -HfO2 system is characterized by negative deviations of its thermodynamic properties from the ideal behavior. Consistency of the obtained modeling results indicate reasonable uniformity of the energy parameters of the lattice model derived in calculations of the hafnia-containing oxide systems, which may be used in further modeling of multicomponent systems.

A Magnetocaloric Glass from an Ionic-Liquid Gadolinium Complex.

[Gd5 (L)16 (H2 O)8 ](Tf2 N)15 was obtained from reaction of Gd2 O3 with 1-carboxymethyl-3-ethylimidazolium chloride (LHCl). The material was found to be an ionic liquid that freezes to glassy state on cooling to -30 °C. Variable-temperature magnetic studies reveal the presence of weak magnetic intramolecular interactions in the glass. Isothermal variable-field magnetization demonstrates a magnetocaloric effect (MCE), which is the first finding of such an effect in a molecular glass. This MCE is explainable by an uncoupled representation, with a magnetic entropy change of -11.36 J K-1 kg-1 at 1.8 K for a 0-7 T magnetic field change, and with a refrigerant capacity of 125.9 J kg-1 , in the 1.8-50 K interval.

Synthesis of Optical Nd:(Y,Gd)2O3 Ceramics and Investigation of Its Spectroscopic Characteristics

Synthesis of Optical Nd:(Y,Gd)2O3 Ceramics and Investigation of Its Spectroscopic Characteristics

Effect of Gd3+ Doping on Sol-Gel Prepared Y₂O₃ Films as Gate Insulators for Oxide Thin Film Transistors.

The relationships between the microstructure and the dielectric properties of sol-gel prepared Y₂O₃ films with various Gd3+ doping were systematically investigated. Robust solution processed lanthanide films, (Y1-xGdx)₂O₃ (0 < x ≤ 0.5), are demonstrated as high-k gate insulators for low voltage-driven oxide thin film transistors and their optimized composition is presented. With the proper amount of Gd3+ doping, the corresponding thin film insulators exhibit low leakage current with increased dielectric constant. The resultant Zn-Sn-O/(Y, Gd)₂O₃ TFT exhibits enhanced performance, by a factor of 10.7 compared with TFTs using a SiO2 insulator, with a field-effect mobility of ~3.15 cm²V-1s-1 and an exceptionally low operating voltage <15 V.

A review: X-ray excited luminescence of gadolinium based optoelectronic phosphors.

X-ray excited fluorescence tomography is an emerging field in the application of bio-imaging and computer tomography. Some rare-earth doped inorganic phosphors like gadolinium oxide (Gd2 O3 ), yttrium oxide (Y2 O3 ), zinc tungstate (ZnWO4 ), cesium fluoride (CsF), barium fluorochloride (BaFCl), lanthanum oxybromide (LaOBr) are shown outstanding applications for X-ray excited phosphors. Gadolinium (Gd)-based inorganic phosphors show extraordinary applications in the field of X-ray chromatography and computer chromatography. In this review article, we discussed the general information about X-ray excited luminescence (XEL) phosphor. Further, we discussed importance, synthesis, structural and photoluminescence (PL) properties of rare-earth (Europium (Eu)) doped Gd2 O3 . To elaborate the scope of the review, we have discussed synthesis, structural and optical properties of lithium (Li) doped Gd2 O3 :Eu. At the end of the review, synthesis, structural and optical properties of Eu doped lutetium oxide (Lu2 O3 ) have been discussed and the results compared with Eu doped Gd2 O3 . The comparison provided the understanding of structural and optical peak position of host and the dopant (Eu).

Синтез оптической Nd:(Y,Gd)2O3-керамики и исследование ее спектроскопических характеристик

Fabrication of optical ceramics based on solid solution of yttrium and gadolinium sesquioxides activated by Nd3+ ions was reported. Nanopowder of Nd0.08(Y0.496Gd0.496)2O3 synthesized by laser ablation method was used as raw material. It was determined that laser-ablated nanoparticles initially have monoclinic phase transformation of which into cubic phase is started at the temperature of 1100 °C and fully completed at 1300 °C. It was found that the best transparency of samples (79.9% at the wavelength of 1060 nm) and lowest content of scattering centers of 2.7 ppm are reached by vacuum sintering of nanopowder previously calcined at 1000 °C for 3 h. A blue-shift of Nd3+ emission bands in (Y,Gd)2O3 matrix with respect to Y2O3 was observed as a result of measuring of photoluminescence spectrum. Broadening of emission bands and their partial overlap was determined suggesting the alteration of local environment of neodymium which embeds into positions of yttrium as well as gadolinium.

In vivo immunotoxicity of Gd2 O3 :Eu3+ nanoparticles and the associated molecular mechanism.

The in vivo toxicity of Gd2 O3 :Eu3+ nanoparticles (NPs) used as dual-modal nanoprobes for molecular imaging has not been studied, and the corresponding molecular mechanism of immunotoxicity remains unknown. In this study, we investigated the cytotoxicity, in vitro apoptosis, and in vivo immunotoxicity of Gd2 O3 :Eu3+ NPs. The NPs showed little immunotoxicity to BALB/c mice. We explored the possible role of the phosphoinositide 3-kinase (PI3K) signaling pathway and found that reactive oxygen species could act as secondary messengers in cellular signaling, inhibiting PI3K expression in the liver. The immune suppression caused by PI3K inhibition helped the mice adapt to stress. The immunotoxicities caused by Gd2 O3 :Eu3+ and gadodiamide, a commonly used contrast agent, were not significantly different, and the mice were able to tolerate the immunotoxicity caused Gd2 O3 :Eu3+ NPs in vitro and in vivo experiments. The results suggest that Gd2 O3 :Eu3+ NPs are sufficiently biocompatible to be used safely in preclinical applications and show promise as bio-imaging agents. Moreover, the in vivo molecular mechanism of immunotoxicity caused by the Gd2 O3 :Eu3+ NPs provides a platform for further research on the immunotoxicity of nano-sized biomaterials.