Effects of Dysprosium Oxide Doping on Microstructure and Properties of Barium Titanate Ceramic

Different amounts of dysprosium oxide were incorporated into barium titanate powders synthesized by hydrothermal method. Relations of substitution behaviors and lattice parameters with solid-solubility were studied. Furthermore, the influences of dysprosium oxide doping fraction on grain size and dielectric properties of barium titanate ceramic, including dielectric constant and breakdown electric field strength , were investigated via scanning electron microscope, X-ray diffraction and electric property tester. The results show that dysprosium oxide can restrain abnormal grain growth during sintering and that fine-grained and high density of barium titanate ceramic can result in excellent dielectric properties. As mass fraction of dysprosium oxide is 0.6%, the lattice parameters of grain increase to the maximum because of the lowest vacancy concentration. The electric property parameters are cited as following： dielectric constant （25 ℃ ） reaches 4100, the change in relative dielectric constant with temperature is - 10% to 10% within the range of - 15 - 100 ℃, breakdown electric field strength （alternating current） achieves 3.2 kV·mm^-1, which can be used in manufacturing high voltage ceramic capacitors

Dissolution-regrowth of hierarchical Fe-Dy oxide modulates the electronic structure of nickel-organic frameworks as highly active and stable water splitting electrocatalysts

As the kinetically sluggish oxygen evolution reaction(OER)is considered to be a bottleneck in overall water splitting,it is necessary to develop a highly active and stable electrocatalyst to overcome this issue.Herein,we successfully fabricated a three-dimensional iron-dysprosium oxide co-regulated in-situ formed MOF-Ni arrays on carbon cloth(FeDy@MOF-Ni/CC)through a facile two-step hydrothermal method.Electrochemical studies demonstrate that the designed FeDy@MOF-Ni/CC catalyst requires an overpotential of only 251 mV to reach 10 mA cm-2 with a small Tafel slope of 52.1 mV dec-1.Additionally,the stability declined by only 5.5%after 80 h of continuous testing in 1.0 M KOH.Furthermore,a cell voltage of only 1.57 V in the overall water splitting system is sufficient to achieve 10 mA cm-2;this value is far better than that of most previously reported catalysts.The excellent catalytic performance originates from the unique 3D rhombus-like structure,as well as coupling synergies of Fe-Dy-Ni species.The combination of lanthanide and transition metal species in the synthesis strategy may open entirely new possibilities with promising potential in the design of highly active OER electrocatalysts.

Dielectric Properties at High Frequency of BSTO System Doped Dy_2O_3

Samples doped with different amount of dysprosium oxide into barium strontium titanate (BSTO) were prepared. Dielectric properties of the samples at high frequency were discussed. X-ray diffraction (XRD) method was employed for analyzing and comparing with the changes in the crystal lattice of the samples,and information of crystal growth was obtained through method of environmental scanning electron micrograph (ESEM). Influence of dysprosium oxide doping on dielectric properties of BSTO based ceramic system at high frequency was studied. Phenomenological coefficients of the samples were calculated on the base of tunability.

Synthesis of Dy_2O_3 nanoparticles via hydroxide precipitation: effect of calcination temperature

This work described the preparation of dysprosium oxide, Dy203, nanoparticles using the homogeneous precipitation method. Dy3＋ ions were precipitated using NaOH solution. The obtained product was filtered, dried, and then calcined for 1 h at the temperature range of 300-700 ℃ in static air. The calcination temperature of the Dy-precttrsor was chosen based on its decomposi- tion as indicated by the TGA analysis. The crystalline structure and surface morphology of the calcined solids were studied by X-ray diffraction （XRD）, field emission scanning electron microscopy （FE-SEM）, transmission electron microscopy （TEM） and X-ray pho- toelectron spectroscopy （XPS）. The obtained results revealed that Dy203 with crystallites size of 11-21 nm was formed at 500 ℃. Such value increased to 25-37 nm for the sample calcined at 700 ℃.

Physical, structural and optical studies on magnesium borate glasses doped with dysprosium ion

Intense visible emissions from dysprosium(Dy3+) ions doped glasses became prospective for diverse technological applications. In this paper, physical, optical and structural properties of magnesium borate glasses doped with varied concentrations of DyOwere examined. Such glasses were synthesised by melt quenching method and characterized at room temperature using several analytical techniques.Luminescence and absorption spectra(in the visible region) of as-quenched samples were used to evaluate the physical and optical properties. XRD pattern confims the amorphous state of as-quenched samples. The Fourier transform infrared(FTIR) spectra of glasses reveal various bonding vibrations assigned to different functional groups. UV-vis-NIR spectra disclose eight absorption bands accompanied by a band for hypersensitive transition positioned at 1260 nm(~6 H→~6 F). The values of direct and indirect optical energy band gap of the studied glasses are decreased with the increase of Dyion contents. The photoluminescence spectra of all glasses under the excitation of 380 nm display two prominent emission bands centred at 497 nm(~4 F→~6 H, blue) and 587 nm(~4 F→~6 H, green).The achieved intense luminescence from the proposed glass composition may be beneficial for solidstate laser applications.

Surface hardness,thermal,optical,and photon attenuation coefficients assessment for dysprosium-doped tellurite glasses

Using a melt-cooling process with the host glass,Dy_(2)O_(3)(1 wt%,2 wt%,3 wt%,and 4 wt%) doped tellurite glasses were produced.A(65-x)TeO_(2)-20B_(2)O_(3)-10Al_(2)O_(3)-SGeO_(2)-xDy_(2)O_(3) glass system was analyzed by Xray diffraction.The patterns have a hump at 2θ=27°-29° and no sharp peaks,indicating that all the glass samples are amorphous.The Vickers microhardness determines how resistant a glass is to persistent deformation produced by a harder substance.Differential scanning calorimetry(DSC) at 300-550℃ was used to evaluate the thermal properties of the Dy_x glass samples.The glass transition temperature T_g(small endothermic peak),start crystallization temperature T_x and crystallization temperature T_c can all be seen on the DSC thermogram(exothermic peaks).The UV-Vis transmittance and absorption spectra were measured.The optical data show that the values of E_d^(ir),E_g^(Ind) and E_U decrease as the amount of Dy_(2)O_(3)increases,indicating a narrowing of the tails due to localized states in the forbidden gap.A concentration quenching event occurs when Dy^(3+) concentrations are above a certain threshold(1%).The addition of Dy_(2)O_(3) increases glass density,while the addition of other Dy(Ⅲ) oxides increases sample density.The radiation shielding values change as a consequence of density fluctuation.The sample with the highest amount of Dy_(2)O_(3)(Dy_(4)) has stronger radiation shielding characteristics;hence,it is superior in terms of shielding outcomes at all energy levels.Such Dy_x samples can be used in various forms of ionizing radiation shielding.

Illumination interface stability of aging-diffusion-modulated high performance InZnO/DyO_(x) transistors and exploration in digital circuits

In current study,the rare-reported solution-driven DyO_(x)films have been prepared to act as the dielectric layer of high performance InZnO/DyO_(x)thin film transistors(TFTs).Annealing temperature dependent thermal decomposition,morphology,crystallization behavior,and chemical compositions of DyO_(x) and InZnO films have been investigated respectively.Results have demonstrated that air-annealed InZnO/DyO_(x)TFTs possess the improved electrical performance,including ultrahigh on/off current ratio of 1×10^(9),larger saturation mobility of 12.6 cm^(2) V-1 s^(-1) and negligible hysteresis after 10 d aging diffusion in the relative humidity(RH)of 40%air ambient,which has been explored by the variable range-hopping(VRH)percolation model and energy band theory.The distinct illumination bias stability can be attributed to the generated various interface defects and concluded that the white light illuminated TFT behaves the higher stability with the smaller threshold voltage shift of 0.25 V.To confirm its feasible application in digital circuit,a resistor-loaded inverter based on InZnO/DyO_(x)TFTs has been constructed.A high gain of 10.1 and good dynamic response behavior have been detected at a low operating voltage of 2 V.As a result,it can be inferred that diffusion-induced enhanced carrier transporting mechanism is an economical and effective method to optimize the electrical performance of solution-derived InZnO/DyO_(x)TFTs,indicating its potential application prospects in flexible transparent electronics with low power consumption.