Search

Multifunctionality and self-powering are key technologies for next-generation wearable electronics. Herein, an interdigitated MXene/TiS

Developing a low-temperature fabrication strategy of an amorphous InGaZnO (α-IGZO) channel layer is a prerequisite for high-performance oxide-based thin film transistor (TFT) flexible device applications. Herein, an ultraviolet-assisted oxygen ambient rapid thermal annealing method (UV-ORTA), which combines ultraviolet irradiation with rapid annealing treatment in an oxygen atmosphere, was proposed to realize the achievement of high-performance α-IGZO TFTs at low temperature. Experimental results have confirmed that UV-ORTA treatment has the ability to suppress defects and obtain high-quality films similar to high-temperature-annealing-treated samples. α-IGZO/HfAlO TFTs with high-performance and low-voltage operating have been achieved at a low temperature of 180 °C for 200 s, including a high μ

Due to the quantum confinement and edge effects, there has been ongoing enthusiasm to provide deep insight into graphene quantum dots (GQDs), serving as attractive semiconductor materials.

In current study, the rare-reported solution-driven DyOx films have been prepared to act as the dielectric layer of high performance InZnO/DyOx thin film transistors (TFTs). Annealing temperature dependent thermal decomposition, morphology, crystallization behavior, and chemical compositions of DyOx and InZnO films have been investigated respectively. Results have demonstrated that air-annealed InZnO/DyOx TFTs possess the improved electrical performance, including ultrahigh on/off current ratio of 1 × 109, larger saturation mobility of 12.6 cm2 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/DyOx 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/DyOx TFTs, indicating its potential application prospects in flexible transparent electronics with low power consumption.

In this article, the preparation of HfLaOx gate dielectric thin films by the spin coating method is proposed. The in-depth physical properties of the as-prepared HfLaOx films were investigated as functions of annealing temperatures. Decided by the key performance indicators of current density, smooth surface, and areal capacitance of HfLaOx films with different annealing temperatures, optimized performance parameters with annealing temperature 550 °C have been obtained. To verify the feasibility of HfLaOx films as dielectric material, In2O3/HfLaOx thin-film transistors (TFTs) have been fabricated and device characterizations have been carried out. As a result, it has been detected that the In2O3/HfLaOx TFTs with optimized annealing temperature of 300 °C demonstrate superior electrical performance, including a high ${I}_{ \mathrm{\scriptscriptstyle ON}} / {I}_{ \mathrm{\scriptscriptstyle OFF}}$ of ~106, a high $\mu _{\text {FE}}$ of 17.09 cm2V−1s−1, a low ${V}_{\text {TH}}$ of 0.09 V, a small interfacial trap states ( ${D}_{\text {it}}$ ) of $1.94\times 10^{{12}}$ cm−2, and a small threshold voltage shift of 0.23 V under PBS test and 0.11 V under NBS test after 3600 s bias stress, respectively. To confirm TFTs’ potential applications in logic circuits, a resistor-loaded inverter was integrated and the maximum voltage gain of 7.60 was demonstrated at an ultra-low operating voltage of 2.5 V. Current observations have indicated the great application prospects of solution-derived HfLaOx-gated TFTs in low-cost and excellent performance electronic devices.

With widespread application of flexible electronic devices, the multifunction for supercapacitors has attracted tremendous attention. Here, developed is a novel multifunctional MXene-based pizeoelectrochemical-type pressure sensor based on highly compressible antiwater supercapacitor. This novel design realizes energy storage and pressure sensing functions simultaneously. The outstanding rate performance is realized by the reasonable design of electron and ion transport channels, originating from strong synergistic bridging interactions between silver nanowires (AgNWs) and MXene. Serving as the electrochemical storage device, even at large 500 mV s

Three dimensional (3D) of CeO2 nanostructures such as convex lens-like, hollow triangular prism, broccolilike, grapelike CeO2 have been successfully synthesized by cerium carbonate hydroxide (CeOHCO3) precursors, which were prepared by a hydrolysis process followed by a facile hydrothermal method without using any template or surfactant. The influence of urea amount on CeO2 nanostructures was discussed. The synthesizing mechanism and the morphological evolution of CeOHCO3 and CeO2 were proposed. The CeO2 samples were examined by XRD, SEM, TEM, UV–Vis, PL, and Raman scattering. The UV–Vis absorption spectrum of the CeO2 samples showed that the band gap energy (Eg) in rang of 2.6–2.9 eV, which is lower than that of bulk ceria.

With the rapid development of intelligent portable electronics, the multifunction requirements for electronic devices get higher and higher. Here, we introduce a novel electrochemical-driven asymmetric supercapacitor-type tactile sensor using cross-linked honeycomb CoV2O6/rGO nanofoam as positive electrode and 1D Ag nanowires integrated with resilient graphene aerogel framework as negative electrode. The novel sensor is integrated with electrochemical-storing and sensing functions, simultaneously. The positive honeycomb CoV2O6/rGO naofoam reveals a high specific capacitance of 1687.7 F g−1 at 1 A g−1, meanwhile negative porous graphene aerogel framework demonstrates high reversible compressibility under strain from 10% to 90%. This electrochemical-driven sensor can realize self-driven and behaves rapid sensitive responses current in the case of detecting strain. The elastic electrochemical-driven sensor not only realizes multi-functionalization of supercapacitor storage devices, but also offers a promising candidate for flexible sensor devices.

CeO2 nano-octahedrons have been successfully synthesized by a facile one-step hydrothermal method. The influences of reaction time on the morphologies, crystal structures, and magnetic properties of the resulting products have been investigated. It is found that morphology is dependent on reaction time. Regular CeO2 nano-octahedrons synthesized at 190 °C exhibit weak but unambiguous room-temperature ferromagnetism (RTFM). However, irregular CeO2 nano-octahedrons synthesized at 250 °C exhibit a stronger RTFM. The enhanced ferromagnetism can be attributed to the effects of the oxygen vacancies and defects from the smaller crystallite sizes.

Gear-like CeO 2 microstructures have been successfully synthesized by a CTAB (cetyltrimethyl ammonium bromide)-assisted hydrothermal method using Ce(NO 3 ) 3 ·6H 2 O as the cerium source and ammonium hydrogen carbonate as the precipitator. X-ray diffraction (XRD) inferred that the synthesized CeO 2 microstructures exhibited a fluorite cubic structure. A scanning electron microscope (SEM) revealed that the CeO 2 microstructures have a gear-like microstructure. X-ray photoelectron spectroscopy (XPS) and the Raman spectroscopy reflected the existence of the oxygen vacancies and Ce 3+ ions in the bowknot-like CeO 2 microstructures. The synthesized CeO 2 shows excellent room temperature optical properties, which is likely associated with Ce 3+ ions and oxygen vacancies in the gear-like CeO 2 samples.

CeO 2 nanopoles have been successfully synthesized by a hydrothermal method using CeC l3 ·7H 2 O as cerium source, NaOH as mineralizer, and ethylenediamine as complexant. The pole-like nano-CeO 2 was examined by XRD, TEM, XPS, UV–vis, PL, and Raman scattering. The results show that the crystallinity of the nanopoles is not so good, and the main valence of cerium is +4. The estimated direct band gaps are 3.014, 3.099, 2.931, and 2.927 eV for the samples synthesized within 2, 18, 50, and 100 h, respectively. These band gaps are smaller than bulk CeO 2 , oxygen vacancies and Ce 3+ ions result in an effective red shifting of the band gap. The visible luminescence exhibits similar emission peaks of room temperature photoluminescence and the emission intensity increases with the increase of concentration of oxygen vacancies and Ce 3+ ions.

Monocrystal CeO2 nanopoles of 15–25 nm in diameter and 300–900 nm or more in length were synthesized within 100 h using hydrothermal method with CeCl3·7H2O as cerium source, NaOH as mineralizer, and ethylenediamine as complexant. The results of XRD and SADE analysis indicate that the as-synthesized CeO2 samples have the fluorite structure. The band gaps of CeO2 samples are 0.08–0.38 eV smaller than that of bulk CeO2. X-ray photoelectron spectroscopy shows that the concentration of Ce3+ is higher than 20% for CeO2 samples. All the as-synthesized CeO2 samples exhibit the room temperature ferromagnetism (RTFM), and the saturation magnetization (Ms) gradually increases with the increase of Eg up to 2.92 eV and then decreases with Eg increasing more. The highest Ms of 0.167 emu/g is obtained from the CeO2 nanopoles synthesized within 100 h. The RTFM mechanism of CeO2 nanopoles has been proposed which can be mainly attributed to the influence of oxygen vacancies and Ce3+ ions.

Morphology control of CeO 2 nanostructures was achieved by using ethanol/water mixtures with varied volume ratios from 0:1 to 1:0 in a facile hydrothermal process with CeCl 3 ⋅7H 2 O as cerium source and N 2 H 4 ⋅H 2 O as mineralizer. It was found that the increase of ethanol/water ratio resulted in the morphology change from thin nanorods to short-thick nanorods, and then to nanoparticles, which is mainly attributed to the influences of hydrocarbon chains, dielectric constant, and viscosity of the solution on the thermodynamics of the reaction system and kinetics of nucleation. Various characterization techniques have been used to study the CeO 2 nanostructures, including XRD, XPS, SEM, HRTEM, Raman, and PL spectra. Photoluminescence spectra of the CeO 2 nanoparticals exhibited an unique UV–violet–blue emission which is likely associated with the defect states existing extensively between Ce 4f and O 2p bands, better crystallinity of the sample, and higher concentration of Ce 3+ ions in sample.

The hexagonal rotor-like cerium carbonate hydroxide (CeCO3OH) and CeO2 nanostructures were successfully synthesised via a facile hydrothermal method using Ce(NO3)3 · 6H2O as the cerium resource, HNO3 additive to form an acidic solution, CO(NH2)2 as both precipitator and carbon source and polyvinylpyrrolidone as surfactant. Characterisation techniques using an X-ray diffractometer, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy, thermogravimetric differential thermal analysis apparatus and UV–vis absorption spectrum have been used for studying the roles of Ce(NO3)3 · 6H2O and HNO3. It was found that the amount of Ce(NO3)3 · 6H2O has an obvious effect on the morphology of the as-synthesised CeCO3OH and CeO2 nanostructures, whereas HNO3 has a significant influence on the crystalline phase. CeO2 has a higher UV absorption than as-synthesised CeCO3OH, which is likely associated with the charge-transition between Ce3+ and Ce4+.

The novel carbon- or chromium-doped TiOXphotocatalysts with different oxygen defects were synthesized by mechanochemical technique and heating process. The samples were characterized by X-ray diffraction, UV-vis spectrophotometer, and fluorescence spectrometer. Carbon and chromium species were incorporated into TiOXcrystal matrix. The mass fraction of Ti7O13in TiOXphotocatalysts could be tunable through carbon or chromium doping. The mass fraction of Ti7O13could be an indication of the degree of oxygen defects (the concentration of Ti3+) in the TiOX. The degree of oxygen defects increased for carbon doping, while the degree of oxygen defects decreased for chromium doping. The photocatalytic activity measurement results showed that photodegradation rate of methyl orange reached the maximum value with mass fraction of Ti7O13of about 66.93%, but the photodegradation rate decreased when mass fraction of Ti7O13is raised further. In addition, the origin of absorption in the visible spectral range for carbon-doped TiOXas well as the effect of band gap on photocatalytic activity has also been discussed in this paper.

Bowknot-like CeO 2 microstructures have been successfully synthesized by a CTAB (cetyltrimethyl ammonium bromide)-assisted hydrothermal method using Ce(NO 3 ) 3 ·6H 2 O as cerium source and urea as mineralizer. X-ray diffraction (XRD) inferred that the synthesized CeO 2 microstructures exhibited a fluorite cubic structure. A scanning electron microscope (SEM) revealed that the CeO 2 microstructures have a bowknot-like microstructure. X-ray photoelectron spectroscopy (XPS) and the Raman spectroscopy reflected the existence of the oxygen vacancies and Ce 3+ ions in the bowknot-like CeO 2 microstructures. Magnetization measurements exhibited room temperature ferromagnetism (RTFM) with a saturation magnetization ( M s ) of 3.97×10 −3 emu/g and coercivity ( H c ) of 200 Oe, which is likely associated with Ce 3+ ions and oxygen vacancies in the bowknot-like CeO 2 samples.

The phonon, elastic and thermodynamic properties of L12phase Rh3Ta have been investigated by the density functional theory (DFT) approach combined with the quasi-harmonic approximation model. The results of the phonon band structure show that L12phase Rh3Ta possesses dynamical stability in the pressure range from 0–80 GPa due to the absence of imaginary frequencies. The pressure dependences with the elastic constants C[Formula: see text], shear modulus G, bulk modulus B, Young’s modulus Y, Poisson’s ratio and B/G ratio have been analyzed. The results of the elastic properties studies show that L12phase Rh3Ta compound is mechanically stable and possesses a higher hardness, improved ductility and plasticity under higher pressures. The pressure and temperature relationship of the thermodynamic properties, such as the Debye temperature [Formula: see text], heat capacity C[Formula: see text], thermal expansion coefficient [Formula: see text] and the Grüneisen parameter [Formula: see text] are predicted by the quasi-harmonic Debye model in a wide pressure (0–80 GPa) and temperature (0–750 K) ranges.

We have investigated the phonon, mechanical and thermodynamic properties of B2-phase AlY under high pressure by performing density functional theory (DFT). The result of phonon band structure shows B2-phase AlY exhibits dynamical stability. Then, the elastic properties of AlY under high pressure have been discussed. The elastic constants of AlY increase monotonically with the increase of the pressure and all the elastic constants meet the mechanical stability standard under high pressure. By analyzing the Poisson’s ratio [Formula: see text] and the value of B/G of AlY, we first predicted that AlY undergoes transformation from brittleness to ductility at 30 GPa and high pressure can improve the ductility. To obtain the thermodynamic properties of B2-phase AlY, the quasi-harmonic Debye model has been employed. Debye temperature [Formula: see text], thermal expansion coefficient [Formula: see text], heat capacity C[Formula: see text] and Grüneisen parameter [Formula: see text] of B2-phase AlY are systematically explored at pressure of 0–75 GPa and temperature of 0–700 K.

CeO 2 nanopoles have been successfully synthesized by a hydrothermal method using CeCl 3 ·7H 2 O as cerium, NaOH as mineralizer, and ethylenediamine as complexant. X-ray diffraction (XRD) and selective area electron diffraction (SAED) infered that the as-synthesized CeO 2 nanopoles exhibited a fluorite cubic structure and monocrystalline phase. Scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that CeO 2 have pole-like nanostructures. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy reflected the existence of the oxygen vacancies and Ce 3+ ions in the CeO 2 nanopoles. Magnetization measurements exhibited room temperature ferromagnetism (RTFM) with saturation magnetization ( Ms ) of 0.167 emu/g, and coercivity ( H C ) of 165 Oe, which is likely associated with Ce 3+ ions and oxygen vacancies in the CeO 2 nanopoles.

CeO 2 nanopolyhedra and square-like nanoparticles were selectively synthesized by a novel hydrothermal synthesis process with the aid of different surfactants, using Ce(NO 3 ) 3 ⋅ 6H 2 O as cerium resource and N 2 H 4 ⋅ H 2 O as mineralizer. The products were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. CeO 2 nanopolyhedra were prepared using polyvinyl pyrrolidone as surfactant, while square-like CeO 2 nanoparticles were prepared using ethylenediamine as surfactant. The possible morphology-selective synthetic mechanism was investigated. X-ray photoelectron spectroscopy measurement revealed that the main valence of cerium irons in the nanopolyhedra was tetravalent, and the subordinate was trivalent which results in formation of oxygen vacancies.

The phonon, elastic and thermodynamic properties of L12 phase Rh3Zr have been investigated by density functional theory approach combining with quasi-harmonic approximation model. The relaxed lattice parameters of L12 phase Rh3Zr at zero pressure are in good agreement with the experiment. To judge the stability of L12 phase Rh3Zr under high pressure, the phonon band structure has been studied. The results show that L12 phase Rh3Zr possesses dynamical stability in the pressure range from 0[Formula: see text]GPa to 80[Formula: see text]GPa due to the absence of imaginary frequencies. The pressure dependences of elastic constants [Formula: see text] have been analyzed. All the elastic constants of Rh3Zr in a wide pressure range (0–80[Formula: see text]GPa) meet general mechanical conditions, suggesting that L12 phase Rh3Zr is mechanically stable under pressure up to 80[Formula: see text]GPa. L12 phase Rh3Zr exhibits ductility under high pressure and the pressure can improve the ductility from the results of the value of [Formula: see text] and Poisson’s ratio [Formula: see text]. Hence, it is obvious that the mechanical properties of Rh3Zr can be improved under high pressure. Moreover, we have obtained the thermodynamic properties using the quasi-harmonic Debye model. We note that the effect of the temperature on the Debye temperature [Formula: see text] is smaller than that of the pressure. We believe that our result will be a good guidance to future works and applications.

In this paper, we employ first-principles methods based on electronic density functional theory (DFT) to investigate the phase stability, elastic and thermodynamic properties of Zr – Al binary substitutional alloys which are Zr 3 Al , Zr 2 Al , ZrAl , ZrAl 2 and ZrAl 3. By analyzing the elastic constants and enthalpy of formation, those phases both satisfy the generalized stability criteria and the results show that ZrAl 2 is the most stable. Due to high bulk modulus B, shear modulus G and Youngs modulus Y, ZrAl 2 also possesses excellent mechanical properties. Moreover, it is expected that there will be covalent bonding between Zr and Al atom in ZrAl 2 compound, which is confirmed by the electronic structure and the differences of charge density discussions. In the end, based on the calculated elastic modulus, the elastic wave velocity, Debye temperature ΘD and specific heat CV are discussed. As a result, ZrAl 3 possesses the highest Debye temperature and sound velocity, meaning a larger associated thermal conductivity and higher melting temperature.

Ceria (CeO2) nanoparticles were successfully synthesised by a novel hydrothermal synthesis process using Ce(NO3)3·6H2O as cerium source and hydrazine hydrate (N2H4·H2O) as mineraliser. The crystal phases, surface morphology and optical properties of CeO2 nanoparticles were characterised by X-ray diffraction, scanning electron microscope, UV-vis spectrophotometer and fluorescence spectrometer. The particle size (ranging from 10 to 20 nm) decreases with the increase of N2H4·H2O from 2 to 8 ml and its mechanism has been proposed and can be mainly attributed to the effect of N2H4·H2O on OH− ionic concentration in the solution. The lattice parameter (∼0.54 nm) decreases with the increase of the crystallite size that can be attributed to both lattice relaxation and valence effect of Ce ions. The absorbance in UV light region increases with the increases of N2H4·H2O from 2 up to 6 ml and then decreases when the dosage of N2H4·H2O is 8 ml. The bandgap energy increases from 3.13 to 3.23 eV with the increases of N2H4·H2O from 2 up to 6 ml because of electrostatic potential effect and then decreases to 2.97 eV when the dosages of N2H4·H2O is 8 ml. The emission intensity increases with the increase of N2H4·H2O from 2 ml up to 6 ml and then unobviously decreases when dosage of N2H4·H2O is 8 ml.