73 results about "Spontaneous polarization" patented technology

The invention belongs to the technical field of lithium ion solid-state batteries, and relates to a composite polymer electrolyte membrane as well as a preparation method and application thereof. The preparation method of the composite polymer electrolyte membrane comprises the following steps: generating a precursor salt containing Ba and Ti on the surface of an inorganic solid electrolyte through a wet chemical method, and forming a compact barium titanate coating layer on the surface of the electrolyte in a high-temperature calcination process to obtain the barium titanate surface modified inorganic solid electrolyte; uniformly dissolving a high-molecular polymer material, the barium titanate surface modified inorganic solid electrolyte and a lithium salt in a solvent, heating and stirring to prepare a uniform solution; and drying to form a membrane to obtain the polymer composite electrolyte membrane. Barium titanate has a special piezoelectric property and can be spontaneously polarized in a crystal structure to generate a polarization field, and the polarization field can sensitively sense the nonuniformity of lithium ion transmission dynamics and interact with the nonuniformity to balance the transmission process of lithium ions in the solid electrolyte, so that the bottleneck problem of ion migration in the traditional electrolyte is solved.

In a semiconductor element including a silicon carbide heterostructure, the resistance component generated due to spontaneous polarization at the hetero-matched interface is suppressed, thereby reducing the specific on-resistance of the semiconductor element. A hetero-matched interface (S X ) and 1 × 10 19 cm -3 The tunnel doped region (D T By providing the layer, a carrier transport mechanism by tunneling is realized, and the specific on-resistance of the semiconductor element is kept low.

A piezoelectric actuator comprises a stack of a plurality of piezoelectric films, a piezoelectric element having electrodes disposed between the piezoelectric films and at both end surfaces, and a drive circuit. Each of the plurality of piezoelectric films has asymmetric polarization-voltage hysteresis characteristics with two different absolute values of coercive voltage. The drive circuit applies a unipolar voltage waveform that generates an electric field in the same direction as the direction of spontaneous polarization in at least one layer from among the plurality of piezoelectric films and generates an electric field in the direction opposite to the direction of spontaneous polarization in the other piezoelectric films. A minimum voltage value V1 having a minimum absolute value in the unipolar voltage waveform is set such that the ratio of the slope T0 at 0 [V] to the slope T1 at the minimum voltage value V1 [V] in a hysteresis curve indicating bipolar polarization-hysteresis characteristics in another piezoelectric film satisfies |T0 / T1| ≥ 1.5.

A ferroelectric liquid crystal (FLC) material for the deformed helix FLC (DHFLC) electro-optical mode devices and shows optimum electro-optical properties including high tilt angle (>38°), and short helix pitch (<120 nm), and spontaneous polarization (>100 nC / cm2) comprising at least two components, wherein at least one FLC component is a chiral compound of Formula (I):particularly:wherein W1 and W2 are chiral groups with polar substituent at chiral centre, A and B are independently N atom or CH groups providing that at least one of A or B is N atom. Other various groups are as defined herein.

A method for searching for ferroelectric materials, such as wurtzite crystal structures, that have low coercive fields and high spontaneous polarization values ​​using first-principles calculations is provided. [Solution] The method includes a first extraction step of obtaining, from a crystal structure database, ferroelectric material candidates with non-centrosymmetric symmetry as first candidates; a calculation step of calculating the band gap value, polarization reversal barrier energy value, and spontaneous polarization value of each first candidate obtained in the first extraction step using first-principles calculations; an insulating property determination step of determining whether the calculated band gap value satisfies insulating properties; a polarization reversal determination step of determining whether the calculated polarization reversal barrier energy value is within a range in which polarization reversal is possible; a spontaneous polarization determination step of determining whether the calculated spontaneous polarization value is within a range in which ferroelectric properties are exhibited; and a second extraction step of extracting, as ferroelectric materials, first candidates for which the determination results in the insulating property determination step, polarization reversal determination step, and spontaneous polarization determination step are all acceptable.

The utility model belongs to the technical field of LED epitaxial structures, and particularly discloses a wavelength-adjustable LED epitaxial structure, which comprises a patterned substrate, a buffer layer grown on the patterned substrate, a 3D + GR layer grown on the buffer layer, an N layer grown on the GR layer, and a polarization improvement layer grown between the GR layer and the N layer or between the buffer layer and the 3D layer. And the polarization improvement layer sequentially comprises an AlN1 layer, a ferroelectric material layer and an AlN2 layer. According to the utility model, a ferroelectric material layer (BaTiO, PbZrTiO3 and the like) is inserted into an N-type semiconductor, and spontaneous polarization can be generated under the action of an external electric field or stress by utilizing an important characteristic, namely polarization reversibility, of a ferroelectric material. When the ferroelectric material is plated below the N layer (electronic conducting layer), the polarization direction of the ferroelectric material can be regulated and controlled through an external electric field or stress. By adjusting the polarization direction and intensity, the fine adjustment of PN junction energy level distribution can be realized, so that the wavelength can be indirectly and quickly adjusted.

The invention relates to the technical field of accelerators, and particularly discloses a pyroelectric electrostatic analyzer which comprises a vacuum cavity, a first pyroelectric crystal, a second pyroelectric crystal and a temperature controller. The first pyroelectric crystal and the second pyroelectric crystal are arranged in the vacuum cavity; a gap is formed between the first pyroelectric crystal and the second pyroelectric crystal to form a channel; the spontaneous polarization vectors of the first pyroelectric crystal and the second pyroelectric crystal are parallel to each other, and the directions of the spontaneous polarization vectors are consistent; the temperature controller is used for controlling the temperature of the first pyroelectric crystal and the second pyroelectric crystal, so that the polarity of a ferroelectric domain in the pyroelectric crystal with temperature change is changed to generate pyroelectric high voltage, and electric field force is provided for charged particles entering the channel, so that the charged particles meeting the condition can pass through the channel; according to the pyroelectric electrostatic analyzer, a large-size high-voltage power supply and numerous complex high-voltage components are removed, and the pyroelectric electrostatic analyzer has great advantages in the aspects of cost, size and use safety.

The invention provides a pyroelectric effect enhanced gallium oxide infrared detector and a preparation method thereof. The pyroelectric effect enhanced gallium oxide infrared detector sequentially comprises a substrate, a first metal electrode layer, a gallium oxide thin film and a second metal electrode layer from bottom to top, wherein the gallium oxide thin film is in an epsilon crystal phase, and the crystal phase is 1t; 001gt, 001gt; the crystal orientation is a spontaneous polarization direction; the first metal electrode layer and the gallium oxide thin film are arranged on the substrate; 001gt, 001gt; the crystal face forms ohmic contact; the second metal electrode layer is connected with the 1t of the gallium oxide thin film; 00gt to 1gt; and the crystal face forms Schottky contact. When the temperature of the device changes due to the influence of infrared radiation, the intrinsic pyroelectric effect resulting from the change of the spontaneous polarization intensity of gallium oxide and the junction type pyroelectric effect resulting from the temperature sensitivity of a Schottky junction space charge region are superposed, pyroelectric currents in the same direction are generated in an external circuit, signal superposition is realized, and the temperature sensitivity of the device is improved. Therefore, the overall pyroelectric response of the device is obviously improved; and the pyroelectric response of the epsilon-phase gallium oxide film in infrared detection application is improved.

The application provides a manufacturing method of a low-ohmic contact gallium oxide power transistor and a device. 3 The UID layer is then grown on the Fe-doped beta-Ga2O3 substrate by using an epitaxial device, a lightly-doped channel layer is then grown on the UID layer, and then a Si-doped GaN layer is grown by using the epitaxial device; since the spontaneous polarization effect of GaN and the doping are relatively easy, a heavily-doped GaN layer can be easily obtained, the GaN layer is annealed in an oxygen atmosphere at high temperature to form a heavily-doped Ga2O3 cap layer, so that the lattice mismatch between the two is reduced, and the cap layer serves as an ohmic contact layer, then a Ti / Au metal stack is deposited on the cap layer to form a good ohmic contact, so that the on-resistance of the device is reduced, and then the gate is manufactured and electrodes are led out to form the low-ohmic contact gallium oxide power transistor.

The application discloses a screening method and device of piezoelectric anisotropic perovskite material, and high-throughput calculation and screening are performed on tetragonal phase ABO3 perovskite oxide material through first principle calculation, the correlation between piezoelectricity and lattice tetragonality, polarization displacement, spontaneous polarization and elastic constant is pointed out, and the method can be used for screening and guiding design of high-performance piezoelectric material. The application gives a three-dimensional representation of piezoelectric coefficient, re-evaluates the piezoelectric coefficient ratio |d 33 / d 31 | which is widely used at present, and points out the deficiency in representing piezoelectric anisotropy, and can be extended to anisotropy of other piezoelectric materials.

The application relates to the technical field of LEDs, in particular to a GaN-based epitaxial structure growth method for improving anti-static capability, which comprises the following steps: S3: sequentially growing a 10-30 nm Si-doped N-AlGaN layer and a 5-15 nm GaN layer; when the Si-doped N-AlGaN layer is grown, the reaction cavity temperature is set to 900-1200 DEG C, and the pressure is 100 Torr-300 Torr, wherein the Si doping concentration is 10 18 ‑10 19 atom / cm 3 ; when the GaN layer is grown, the reaction cavity temperature is set to 900-1200 DEG C, and the pressure is 100 Torr-300 Torr; S4: the step S3 is repeated for 8-10 times; the application has the beneficial effect that the structure formed by the steps S3 and S4 is a stress release layer, the stress release layer forms an n-type AlGaN / GaN alternating superlattice layer by using high-energy Al, and the short-period superlattice technology route can effectively improve the carrier transport performance, so that when a heterojunction is formed between GaN and AlGaN, spontaneous polarization is generated, and the anti-static performance of the LED epitaxial structure is greatly improved.

This invention discloses a method for establishing a phase-field model of a polycrystalline phase relaxor ferroelectric, the method comprising the following steps: 1. Determining the free energy of the polycrystalline phase relaxor ferroelectric; 2. Determining the order parameter of the polycrystalline phase relaxor ferroelectric as spontaneous polarization. P i 3. Represent free energy as spontaneous polarization P i The invention employs several methods: 1) introducing ferroelectric-ferroelectric phase boundaries and random local electric fields; 2) solving the Ginzburg-Landau partial differential equations to obtain the spatial evolution of spontaneous polarization, thereby determining the domain structure of polycrystalline relaxed ferroelectrics and ultimately establishing a phase-field model for polycrystalline relaxed ferroelectrics. Based on a model ferroelectric system, this invention, by considering ferroelectric-ferroelectric phase boundaries and random local electric fields, reproduces the unique domain structure characteristics of polycrystalline relaxed ferroelectrics with the coexistence of multiple nanometer-sized ferroelectric phases, establishes a phase-field model for polycrystalline relaxed ferroelectrics, and improves the theoretical model of polycrystalline relaxed ferroelectrics, which is beneficial for guiding the design of novel high-performance ferroelectric materials.

The present application relates to a kind of barrier layer structures with asymmetric insertion layer, including barrier layer, barrier layer is used to form source, gate and drain, insertion layer is embedded in barrier layer inside, insertion layer forms first insertion section between source to gate, forms second insertion section between gate to drain, the thickness of first insertion section is less than the thickness of second insertion section;A kind of power device, including barrier layer structure with asymmetric insertion layer.In the present application, the spontaneous polarization, piezoelectric polarization effect of asymmetric insertion layer is much stronger than barrier layer, the insertion layer of gate, drain side is thicker, resulting in local barrier being higher, electric field peak spontaneously migrates from gate edge to drain side and gradually reduces, the distribution of peak electric field is optimized, and the overall performance of device is improved;The breakdown voltage of the present application is effectively improved, peak electric field is significantly reduced, Ron is not degraded basically, current collapse effect is significantly inhibited, meet the design requirements of high-voltage GaN HEMT.

This piezoelectric actuator is provided with a laminated piezoelectric element and a pre-drive circuit. A first piezoelectric film and a second piezoelectric film both have spontaneous polarization aligned in a film thickness direction, and have the same orientation of spontaneous polarization. ΔVcf < ΔVcr - 1.0 is satisfied where ΔVcf is the absolute value |Vcf+ - Vcf-| of the difference between two coercive voltages in a hysteresis curve of one piezoelectric film of the first piezoelectric film and the second piezoelectric film, and ΔVcr is the absolute value |Vcr+ - Vcr-| of the difference between two coercive voltages in the hysteresis curve of the other piezoelectric film thereof. A drive circuit causes the one piezoelectric film to generate an electric field in the same orientation as the orientation of spontaneous polarization, and causes the other piezoelectric film to generate an electric field in the orientation opposite the orientation of spontaneous polarization.

The invention belongs to the field of materials, and particularly relates to a preparation method of a spontaneous polarization reinforced material, which comprises the following steps: heating a mixture containing a material to be reinforced and a modifier for modification treatment to obtain the spontaneous polarization reinforced material, the material to be reinforced comprises LiNbO3, NaxKyNbO3 (0 lt; xlt; 1, y = 1-x), BiFeO3, PbZrxTiyO3 (0 lt; xlt; 0.5, y = 1-x), Bi4Ti3O12, KTaxNbyO3 (0lt; xlt; x = 1-x, 0.5, y = 1-x), BaTiO3, (Bax1Cay1Srz1) (Tix2Zry2Snz2) O3. The modifier comprises at least one of compounds as shown in a formula 1 and / or a formula 2; the temperature of the modification treatment stage is 200-500 DEG C. According to the process, the spontaneous polarization intensity of the material can be effectively enhanced.

The invention relates to the technical field of piezoelectric materials, in particular to a ferroelectric liquid crystal polymer piezoelectric material and a preparation method and application thereof. The ferroelectric liquid crystal polymer piezoelectric material provided by the invention is prepared from raw materials including a chiral ferroelectric liquid crystal monomer, a siloxane compound and a cross-linking agent, the total mole number of double bonds of the chiral ferroelectric liquid crystal monomer and the cross-linking agent is the same as the mole number of silicon-hydrogen bonds in the siloxane compound. According to the ferroelectric liquid crystal polymer piezoelectric material provided by the invention, through accurate component and proportion design, a chiral ferroelectric liquid crystal unit with high spontaneous polarization can be efficiently and stably immobilized into a flexible polymer skeleton; therefore, a novel piezoelectric material with excellent flexibility and mechanical stability and remarkably enhanced piezoelectric property is prepared, and a foundation is laid for application of high-sensitivity flexible sensors.

The application discloses a kind of multilayer co-extrusion forming process of anti-static ton barrel, belong to anti-static ton barrel technical field, comprising: by inside to outside sequentially by high clean induction layer, gradient dielectric adhesive layer, high barrier layer, adhesive layer, structural support layer and composite conductive outer layer of multilayer parison formed by multilayer co-extrusion;Blow molding and cooling setting;Ring copper alloy bus ring is embedded in barrel body bottom and installs elastic ground contact, and ground is led out by shielding wire.This application adds ternary hybrid conductive component in high clean induction layer and constructs quasi-continuous charge bridge, so that internal static charge is led out across interface;Gradient dielectric adhesive layer forms dielectric constant gradient and spontaneous polarization electric field, reduces charge migration energy barrier;Combination gradient cooling solidification filler orientation and inhibit thermal stress.This application realizes the efficient discharge of internal static electricity of ultrahigh resistivity liquid under the premise of maintaining the ultrahigh cleanliness of inner layer, simultaneously has excellent interlaminar bond strength and long-term environmental adaptability.

The application discloses a design and prediction method and system of a two-dimensional multiferroic hydroxide material, and the method is as follows: a standard three-dimensional hydroxide XOOH bulk crystal structure file is acquired, the file is cut by using visual software and a vacuum layer is added in the c direction, and the structure file type is converted into a.vasp file format by means of VESTA software; structure optimization calculation is carried out on the constructed hydroxide monolayer system, and the ferroelectric spontaneous polarization and the ferroelastic spontaneous strain direction are determined; the hydroxyl in the system is rotated and in-plane stress is applied, other ferroelectric phases and ferroelastic phases of the system are found, intermediate phases are found by respectively inserting points between the two ferroelectric phases and the two ferroelastic phases, and the reversal energy barrier between the two ferroelectric phases and the two ferroelastic phases is respectively calculated; the change of the ferroelectric polarization of the system along the ferroelastic transition path is calculated, and the internal mechanism of the coupling of the two ferroelectricities is explained. The method and system platform reduce the experimental trial and error cost, and realize screening / prediction of a two-dimensional ferroelectric and ferroelastic coupled multiferroic material.

The invention provides a solar cell, a preparation method thereof and a photovoltaic module. The solar cell comprises a P-type silicon substrate, wherein a first surface and / or a second surface of the P-type silicon substrate comprises a positive electrode region, a negative electrode region and a groove; a ferroelectric material layer and a negative electrode are sequentially arranged on the surface of the negative electrode region; a tunneling layer, a P-type doped polycrystalline silicon layer, a passivation layer, an antireflection layer and a positive electrode are sequentially arranged on the surface of the positive electrode region. Therefore, the cost of the solar cell is low, and collection of holes is facilitated; the steps of the preparation process are reduced; in the solar cell, a ferroelectric material is adopted to replace a phosphorus-doped polycrystalline silicon layer, the spontaneous polarization characteristic of the ferroelectric material is utilized, the polarization direction can be changed along with an external electric field, when light irradiates a silicon substrate, photon-generated carriers are generated on a silicon wafer, and when the ferroelectric material is in contact with the silicon wafer, the polarization electric field of the ferroelectric material can help the carriers to be separated and perform directional movement, so that the photon-generated carriers are separated; and a P-N structure is formed on the surface of the battery.

The application discloses a gallium nitride-based bipolar junction transistor and a preparation method thereof, and relates to the technical field of semiconductors; a two-dimensional electron gas layer is generated on the side close to a GaN channel layer at the interface between an AlGaN barrier layer and the GaN channel layer through piezoelectric polarization and spontaneous polarization effects; a groove for depositing and growing a P-type semiconductor layer is formed by etching from the middle of the top surface of an insulating layer to the bottom surface of the GaN channel layer; two grooves for depositing and growing an emitter and a collector are formed by etching from the top surface of an emitter insulating layer away from the end of the P-type semiconductor layer and the top surface of a collector insulating layer away from the end of the P-type semiconductor layer to the top surface of an emitter AlGaN barrier layer; a base is deposited and grown on the top surface of the P-type semiconductor layer; and the application can greatly improve the mobility of electrons in the emitter and the collector, and improve the large-current output capability, power density and high-frequency application capability of the device.

The invention discloses a quasi-solid aqueous zinc ion battery based on a ferroelectric coating and a sodium alginate gel electrolyte, and relates to the technical field of electrochemical energy storage. The battery comprises a positive electrode, a ferroelectric coating modified zinc negative electrode and a sodium alginate-based gel electrolyte. The ferroelectric coating is formed by compounding a ferroelectric polymer and zinc salt, zinc ion flux is homogenized by utilizing a built-in electric field generated by spontaneous polarization of the ferroelectric coating, zinc is induced to preferentially deposit, dendritic crystal growth is effectively inhibited, and side reactions are reduced; the sodium alginate-based gel electrolyte has a three-dimensional network structure, has high ionic conductivity and excellent mechanical strength, and can physically block dendritic crystal penetration and eliminate the risk of liquid leakage; the synergistic effect of the two significantly improves the cycling stability and safety performance of the battery, solves the problems of easy short circuit and short service life of the aqueous zinc ion battery, and is suitable for the field of high-safety energy storage.

The application belongs to the technical field of building ceramics, and discloses a kind of negative ion ceramic ink and its preparation method, negative ion ceramic tile.The negative ion ceramic ink contains zirconium niobium-based composite material and tourmaline composite material synthesized independently at the same time, and the two composite materials synergistically act, not only solve the high temperature instability problem of traditional negative ion material, but also ionize air through rare earth energy transfer / lattice distortion polarization and spontaneous polarization, can induce a large number of negative ions, improve air purification efficiency.The application adopts the system of "bottom glaze-function ink-surface glaze", by adjusting the raw material components of bottom glaze and surface glaze, the negative ion material can efficiently and durably induce air negative ions, and the negative ion release amount under visible light conditions can reach 3090-3250 / cm 3 , which exceeds the health level of class I;The purification efficiency of formaldehyde is 93-95%, the persistent purification efficiency is 90-92%, which exceeds the requirements of class II standard.

The invention relates to the technical field of photoelectric detection, in particular to a photoelectric detector and system based on ferroelectric perovskite non-degenerate two-photon absorption. The photoelectric detector comprises a substrate layer; the metal electrode layer is positioned on the substrate layer; the light absorption layer is located on the substrate layer and is composed of a ferroelectric perovskite thin film; the protective layer is formed by a boron nitride film; the metal electrode layers are located on the two sides of the light absorption layer. The photoelectric detector can perform photoelectric detection by using a ferroelectric perovskite non-degenerate two-photon absorption effect, a detection threshold value is reduced by one order of magnitude, and measurable light current can be generated for weak light without high-peak light power; a built-in electric field generated by spontaneous polarization of the ferroelectric perovskite can effectively separate electron-hole pairs, so that the signal-to-noise ratio and the response speed are greatly improved; and the structure is simple, the cost is low, and high-sensitivity and stable detection on weak light can be realized.

The application discloses a two-dimensional hybrid perovskite nanosheet with out-of-plane ferroelectricity and a preparation method and application thereof. The preparation process of the nanosheet is as follows: raw materials including lead iodide, phenethylammonium iodide and methylammonium hydroiodide are dispersed in an organic solvent to obtain a mother liquor; a red precipitate is generated by adding a precipitating solution dropwise into the mother liquor, and supernatant is taken and placed on a lower PDMS substrate; an upper PDMS substrate is covered on the lower PDMS substrate on which the supernatant is placed, and after heat treatment and volatilization of the organic solvent, the upper and lower PDMS substrates are separated. The nanosheet has out-of-plane ferroelectric polarization and single ferroelectric domain characteristics based on organic-inorganic hybridization and a special space group structure, and has advantages of excellent structural stability and conductivity. A two-dimensional photodetector prepared by using the nanosheet can be spontaneously polarized, thereby being self-powered, and the on-off ratio of the photodetector is as high as 10 4 , and a photocurrent can reach 30 nA, thereby greatly improving the comprehensive performance of the photodetector.

The invention discloses a two-dimensional hybrid perovskite nanosheet with out-of-plane ferroelectricity as well as a preparation method and application of the two-dimensional hybrid perovskite nanosheet. The preparation process of the nanosheet comprises the following steps: dispersing raw materials including lead iodide, phenylethyl amine iodide and formamidine hydriodate into an organic solvent to obtain a mother solution; dropwise adding an eluate into the mother liquor to generate a red precipitate, taking a supernatant, and placing the supernatant on a lower PDMS substrate; and covering the upper PDMS substrate on the lower PDMS substrate on which the supernatant is placed, carrying out heat treatment, and after the organic solvent is volatilized, separating the upper PDMS substrate from the lower PDMS substrate. The nanosheet is based on organic-inorganic hybridization and a special space group structure, is endowed with out-of-plane ferroelectric polarization and single ferroelectric domain characteristics, and has the advantages of excellent structural stability, conductivity and the like. The two-dimensional photoelectric detector prepared by adopting the material can be spontaneously polarized so as to be self-powered, the switch ratio of the detector reaches up to 104, the light current can reach 30nA, and the comprehensive performance of the detector is greatly improved.

The invention discloses a multifunctional logic device based on double ferroelectric coupling interfaces and a preparation method thereof, the device comprises a silicon substrate layer and a TiN / Al < 1-x > ScxN / epsilon-Ga2O3 / TiN heterostructure on the silicon substrate layer, the TiN / Al < 1-x > ScxN / epsilon-Ga2O3 / TiN heterostructure comprises a TiN lower electrode layer, an epsilon-Ga2O3 ferroelectric film layer, an Al < 1-x > ScxN ferroelectric film layer and a TiN upper electrode layer which are sequentially stacked from bottom to top; according to the invention, epsilon-Ga2O3 is used as a lower ferroelectric material, Al1-xScxN is used as an upper ferroelectric material, a double ferroelectric heterostructure with polarization coupling characteristics is formed in a stacking mode, and the structure utilizes the ferroelectric response-like characteristic of epsilon-Ga2O3 and the strong spontaneous polarization capability of Al1-xScxN to realize the construction of a multi-polarization stable state in the same device, so that the performance of the device is improved. The method has the characteristics of non-volatility, polarization stability, logic multifunctionality and process compatibility.

The invention relates to the field of solid-state battery positive electrode materials, in particular to a preparation method and application of an inorganic ferroelectric coated oxide positive electrode material. The method specifically comprises the following steps: adding an inorganic ferroelectric into a solvent, and ultrasonically dispersing to obtain turbid liquid; adding an oxide positive electrode material into the solution, controlling the stirring temperature to evaporate the solvent, and then obtaining a uniform mixture of the inorganic ferroelectric and positive electrode particles; and calcining to obtain the ferroelectric coated oxide positive electrode material. According to the invention, the preparation process of the positive electrode coating layer can be greatly simplified through a method of combining solution mixing with high-temperature calcination, and the method has wide universality for coating layer materials with inert ion transmission. Meanwhile, a built-in electric field generated by spontaneous polarization of the ferroelectric material can weaken a space charge layer between the positive electrode and the electrolyte, the potential barrier of ions penetrating through the interface of the positive electrode and the electrolyte is reduced, and transmission of lithium ions is promoted.

The invention discloses a preparation method of a depletion mode and enhancement mode ScAlN / GaN-based HEMT (High Electron Mobility Transistor) with adjusted element components, and belongs to the field of semiconductor devices. The Sc component is utilized to regulate and control spontaneous polarization and piezoelectric polarization of the ScAlN, adjustment of two-dimensional carriers of the ScAlN / GaN heterojunction is achieved, and therefore depletion mode and enhancement mode GaN-based HEMT devices are achieved under the same technical route. According to the invention, only the Sc component of the ScAlN barrier layer needs to be adjusted, the depletion mode HEMT device and the enhancement mode HEMT device with electron or hole conduction can be selectively prepared, and the production technology is simple. The depletion type ScAlN / GaN-based HEMT device provided by the invention can realize higher two-dimensional carrier concentration, and can be applied to the field of high-power circuits. According to the enhanced ScAlN / GaN-based HEMT, the technological process is greatly simplified, the device preparation difficulty is low, and the reliability is better; meanwhile, due to the fact that the process steps are few, damage to the device structure in different stages is smaller, and the device yield is effectively improved.

The application discloses a novel two-dimensional ferroelectric single-atom Ag loaded electrocatalyst Ag@CIPS. By loading transition group metal Ag on the surface of two-dimensional ferroelectric material CuInP2S6 which can maintain ferroelectric polarization at room temperature, a single-atom catalyst Ag@CIPS is prepared, and the catalytic activity of the single-atom catalyst can be regulated by the polarization of the substrate. Due to the regulation of the spontaneous polarization of the ferroelectric substrate on the outer electron structure of the Ag atom, the Ag atom which originally does not have catalytic activity shows good HER activity under the regulation of the substrate. After the single-layer CIPS surface is loaded with Ag, the overpotential of the catalytic HER process is greatly reduced. With the increase of the substrate layer, the polarization intensity of the substrate is enhanced, and excellent HER performance is shown. Moreover, after the single-atom Ag particle is used to modify the CIPS material, the overpotential and Tafel slope of the electrocatalytic hydrogen evolution reaction are reduced, and the catalytic activity is improved.

This invention provides a ferroelectric liquid crystal (FLC) material for a deformable helical ferroelectric liquid crystal (DHFLC) electro-optic mode device. The FLC material exhibits optimal electro-optic properties, including high tilt angle (>38°), short pitch (<120 nm), and spontaneous polarization (>100 nC / cm). 2 The FLC material comprises at least two components, wherein at least one FLC component is a chiral compound of formula (I), particularly a chiral compound of formula (****), wherein W1 and W2 are chiral groups having polar substituents at the chiral center, and A and B are independently N atoms or CH groups, provided that at least one of A or B is an N atom. Other various groups are as defined herein.