18 results about "Electrical transport" patented technology

This invention discloses a method and device structure for improving the electrical transport properties of etched graphene quantum dots, belonging to the field of low-temperature transport testing technology. The method includes the following steps: fabricating etched graphene quantum dot devices; performing preliminary electrical transport characterization by cooling; and undergoing several cycles of "sample electrode grounding protection – heating to above 200K or room temperature – cooling again – electrical transport characterization" to improve the electrical transport properties of the device, enabling subsequent observation and manipulation of the quantum dot's fine charge stability map. The optimized method of this invention, through several heating and cooling thermal cycles, successfully adjusts the coulomb blocking region of the graphene quantum dots from hundreds of volts towards zero, facilitating the application of a gate voltage. Furthermore, the charge stability map of the two quantum dots is significantly optimized and improved, greatly increasing the yield of etched graphene quantum dot devices. In addition, the optimized method of this invention is simple to operate and has significant effects, making it suitable for widespread application.

This invention discloses a method and system for screening high-performance layered nitride thermoelectric materials, comprising: obtaining a series of crystal structures of initial layered nitrides; performing magnetic tests on the materials using first-principles calculations to select non-magnetic materials; optimizing the structure of non-magnetic materials, and after calculation convergence, performing static calculations and electronic band structure calculations to select materials with a band gap range of 0.1~3 eV and high band structure degeneracy; calculating the partial charge density of the materials to determine whether there is a two-dimensional electron gas, i.e., alternating conductive and insulating layers; determining stability by performing phonon spectrum and molecular dynamics simulations on the materials to select materials with no imaginary frequencies in the phonon spectrum and stable dynamics; calculating the thermal transport properties of the materials, obtaining the lattice thermal conductivity and Green'sson parameters, and searching for materials with strong anharmonicity; and finally performing electrical transport calculations to obtain the ZT value of the materials.

The invention discloses a copper ion intercalation two-dimensional beta-phase indium selenide material as well as a preparation method and application thereof. The method comprises the following steps: soaking a substrate loaded with a beta-InSe nanosheet in an organic solution of copper hexafluorophosphate tetraacetonitrile with the pH value of 4.0-6.5, and preparing the copper ion intercalation two-dimensional beta-InSe material through a solution heating and soaking method. According to the copper ion intercalation two-dimensional beta-phase indium selenide material and the preparation method thereof, a mild and efficient copper ion solution intercalation process is adopted, highly uniform and ordered distribution of copper between two-dimensional beta-InSe layers is achieved, the ferroelectric property and the electrical transport property of the copper ion intercalation two-dimensional beta-phase indium selenide material are regulated and controlled at the same time, and the prepared copper ion intercalation two-dimensional beta-phase indium selenide material is suitable for constructing a high-performance ferroelectric device.

This invention provides a molecular device based on weak supramolecular interactions. The molecular device comprises a substrate electrode, a needle electrode, and a single supramolecular element between the two electrodes. The single supramolecular element consists of two model molecules with interchangeable π–π stacking and hydrogen bonding interactions. The molecular device provided by this invention exhibits stable performance and a high on / off ratio. It requires no external stimuli or the participation of other auxiliary molecules. Reversible switching of the electrical transport mode can be achieved by repeatedly stretching and compressing the needle electrode to change the spacing between the model molecules within the single supramolecular element. The device maintains stable lifetime and on / off state switching even at relatively high oscillation frequencies.

The application discloses an electric transport testing device and method for in-situ phase change detection, and mainly relates to the technical field of material in-situ characterization and electric transport measurement. The device comprises a sample stage, a circuit board, a temperature control module and a signal acquisition circuit. The sample stage adopts a T-shaped structure as a whole, screw fixing holes are arranged on the lateral sides of the upper transverse area of the sample stage, and the sample stage is used for mechanical fixation with a sample rod. A plurality of threaded holes are arranged on the left and right sides of the sample stage to adapt to the installation requirements of circuit boards with different lengths. The application has the beneficial effects that the resistivity continuous acquisition and the fixed-point Hall measurement function are integrated in the same testing platform, the R-T curve and the Hall parameter-temperature relationship can be obtained simultaneously in one temperature change process without replacing the sample or re-wiring. Through comprehensive analysis of the resistivity change, the Hall coefficient change and the abnormal Hall magnetic response characteristics, the phase transition temperature, the phase transition type and the electronic structure evolution in the phase transition process of the material can be comprehensively determined from the electric transport angle.

This invention discloses a non-destructive testing system and method for defects in superconducting materials based on thermoelectric electromotive force (TEMF), belonging to the field of non-destructive testing technology for superconducting materials. This method introduces a controllable temperature gradient along the length of a practical superconducting material and monitors the changes in thermoelectric electromotive force generated at both ends or in localized areas of the superconducting material in real time. Utilizing the anomalous response of the electrical transport characteristics of the defect region near the critical temperature, it achieves rapid and non-destructive identification and location of internal defects in the superconducting material. This method does not require disassembly of the superconducting material or application of large currents, and is applicable to various practical superconducting materials such as tapes, wires, and armored cables. It has advantages such as high detection sensitivity, low implementation cost, simple operation, and scalability to online detection.

This application provides a testing device, assembly method, and electrical performance testing method for two-dimensional devices based on a diamond anvil cell, belonging to the field of high-voltage electrical transport measurement technology for two-dimensional materials. The two-dimensional device testing device includes a diamond anvil cell, a metal pad, an insulating part, and a two-dimensional device. The insulating part includes a first insulating part and a second insulating part. Second through holes are formed in the areas corresponding to the first through hole in both the first and second insulating parts. The inner walls of the two second through holes, the upper surface of the lower diamond anvil cell, and the lower surface of the upper diamond anvil cell together form a sample cavity. The two-dimensional device is housed within the sample cavity. The two-dimensional device includes a bottom grid, a first dielectric layer, an in-plane Hall electrode, a two-dimensional material, a second dielectric layer, and a top grid, stacked sequentially. This testing device can simultaneously control the grid voltage and pressure, thereby achieving the measurement of the electromagnetic transport characteristics of the two-dimensional material under the synergistic effect of the grid voltage and pressure.

The invention discloses an in-situ electric transport and quantum magnetics collaborative characterization system, and relates to the technical field of material physical property measurement under extreme conditions, the system comprises a multi-physics field coupling module, the multi-physics field coupling module comprises an extreme pressure device, a vector superconducting magnet and a low-temperature constant-temperature device, the extreme pressure device comprises a diamond anvil cell, and the vector superconducting magnet comprises a quantum magnetic field; comprising a nitrogen vacancy color center, an electrical probe and a microstrip transmission line, the cooperative detection module comprises a magnetic detection terminal and an electrical detection terminal and is used for detecting a magnetic signal of the sample to be detected and performing in-situ measurement so as to characterize the electrical transport property; and the position adjustment and vibration isolation module comprises a vibration isolation platform, and the extreme pressure device and the magnetic detection terminal are jointly rigidly fixed on the vibration isolation platform so as to ensure the alignment stability of the micron-sized optical path. According to the invention, the submicron-level optical alignment stability can be realized while accurate loading in a low-temperature, high-intensity magnetic field and high-pressure environment can be ensured, so that the isotactic in-situ electric-magnetic collaborative data with a high signal-to-noise ratio can be obtained.

The invention relates to a high-performance bismuth telluride-based thermoelectric material and a preparation method thereof. According to the method, a preformed blank is subjected to a multi-stage thermal deformation process, specifically, first-stage thermal extrusion is conducted at the temperature of 430-530 DEG C and the medium extrusion ratio, and densification and texturing are preliminarily completed; then, second-stage hot extrusion is immediately carried out at the temperature of 350-450 DEG C under the high extrusion ratio, and high-density dislocation is introduced through violent plastic deformation; and in the third stage, equal-channel angular pressing can be adopted for subsequent shear deformation, so that the dislocation density is further increased, and grains are refined. By accurately controlling the time sequence and strength of a thermal field and a shear force field, a multi-mode defect structure from a nano precipitated phase and a crystal boundary in-place error network is cooperatively constructed in the material, and full-spectrum scattering of phonons is realized, so that the crystal lattice thermal conductivity is remarkably reduced while good electric transport performance is kept.

The invention relates to the field of thermoelectric materials and semiconductor refrigeration, and discloses a thermoelectric refrigeration material based on a P-type diamond-like carbon-based Cu3SbSe4 crystal and a preparation method of the thermoelectric refrigeration material, the material is an Ag solid solution P-type Cu3SbSe4 crystal material, and the molar ratio of Cu to Ag to Sb to Se is (3-x): x: 1: 4; wherein x is more than or equal to 0.03 and less than or equal to 0.24, and a Bridgman method is adopted. The compact Cu3SbSe4 crystal material is successfully prepared by a method of firstly adjusting a slow cooling temperature zone by optimizing a preparation process and then filling nitrogen to adjust pressure. And the crystal quality and mobility are improved through solid solution Ag, meanwhile, the carrier concentration of the material is maintained, and finally the electrical transport performance of the material is optimized. The P-type Cu3SbSe4 crystal provided by the invention has the advantages of rich source materials, low price, high mechanical strength and the like, a thermoelectric refrigeration device constructed by the P-type Cu3SbSe4 crystal realizes an effective refrigeration effect, and the diamond-like thermoelectric material Cu3SbSe4 has a great potential of becoming a thermoelectric refrigeration material.

The application discloses a novel electrode preparation and wiring process combining indium compression contact and hot air welding method, and relates to the technical field of condensed state physics and material engineering. The application comprises the following steps: S1: processing a millimeter-level bulk phase material sample to be measured into a regular long strip-shaped Hallbar structure for electrical transport measurement, and performing cleaning treatment on the surface of the processed sample. The application cooperates indium compression contact and hot air welding, relies on the good ductility and low resistance characteristics of high-purity indium, forms a gap-free ohmic contact between indium and the surface of the millimeter-level bulk phase sample under constant pressure at room temperature, simultaneously utilizes the low melting point characteristics of Sn-Bi series low-temperature soldering paste, forms a metallurgical bonding solder joint structure between the metal wire and the indium electrode through a precise temperature control hot air welding process, and forms a mutual melting diffusion layer, which effectively solves the problem of loose contact. Compared with a single contact mode, the application not only retains the advantage of small thermal damage of the indium compression method to the sample, but also has high mechanical stability of the welding connection.

This invention relates to the field of thermoelectric materials technology, and discloses a bismuth telluride-based thermoelectric material, its preparation method, and its applications. It includes a matrix and a dopant material; the matrix is ​​bismuth telluride; the dopant material is selected from binary compound materials. The thermoelectric material of this application improves electrical transport performance and increases the power factor by incorporating binary compound materials into the matrix material and combining zone melting, ultrasonic exfoliation, and hot-pressing sintering processes. It also introduces numerous dislocations, grain boundaries, and other defects to effectively reduce lattice thermal conductivity and optimize thermoelectric performance; simultaneously, it significantly improves the Vickers hardness of the bismuth telluride-based thermoelectric material.

In one aspect, a heat transfer apparatus including a heat transfer medium, a liquid distribution system, a fan, and a liquid sensor of the heat transfer medium. The liquid sensor includes a sensing zone configured to detect an electrical transport property that is indicative of a wetness of the heat transfer medium. The sensing zone includes a first plurality of electrode extensions and a second plurality of electrode extensions that mesh with and are spaced apart from the first plurality of electrode extensions. A controller is operably connected to the liquid distribution system and the liquid sensor, the controller configured to operate the liquid distribution system based at least in part on the electrical transport property to achieve a target wetness level of the heat transfer medium.

This invention provides a type of p-type AB2X2-type Zintl phase thermoelectric material, wherein the chemical formula of the p-type AB2X2-type Zintl phase thermoelectric material is Mg. 3‑3x Zn 2x Yb x Sb2 or Mg 3‑3x Zn 2x Ca x Sb2 or Mg 3‑ 3x Cd 2x Yb x Sb2, where x = 0.6~0.8. By solid-solution of YbZn2Sb2, CaZn2Sb2, or YbCd2Sb2 with Mg3Sb2 phase, band structure modulation is achieved, resulting in excellent electrical transport properties while maintaining low thermal conductivity, thus achieving excellent thermoelectric properties. The preparation method of p-type AB2X2 type Zintl phase thermoelectric material provided by the present invention includes: high-energy ball milling of initial raw materials under an inert atmosphere to obtain powder, followed by sintering with spark plasma (SPS) to obtain bulk material. The raw materials used in the above preparation method are abundant, low in cost, and the production process and equipment are simple, with good controllability and repeatability.

The application discloses a kind of simulation analysis method and device of wave propagation characteristic in iced conductor, belong to transmission line icing deicing technical field.Its method with the more common iced transmission conductor in electric power transportation as research object, add icing layer model, obtain iced transmission conductor model;Ring amplitude device model is established on the surface of the iced transmission conductor model and sets domain point probe, and the ring amplitude device model is used to exert force in the iced transmission conductor model to generate ultrasonic guided wave;The propagation characteristics of ultrasonic guided wave in iced conductor are simulated and analyzed under different excitation loading modes by finite element method, the attenuation characteristics of guided wave in iced transmission conductor are obtained, the theoretical effect of ultrasonic deicing of transmission conductor under different excitation frequencies and different excitation loading modes is tested, and the ultrasonic deicing operation of transmission conductor in reality is guided.The present application can greatly improve the deicing efficiency.

The application discloses a high-throughput calculation method of electric transport performance based on deformation potential approximation. In the method, the electron relaxation time involved in the calculation of the electric transport performance is only considered as the electric-acoustic interaction, and the electric-acoustic interaction is described by using the deformation potential approximation. A high-throughput calculation method of the deformation potential constant is developed, the average value of the first band is used as a reference state, and the obtained deformation potential constant dataset is used for high-throughput electric transport performance calculation. Compared with the constant relaxation time approximation and the constant mean free path approximation method, the method has higher precision, and compared with the precise electric-acoustic coupling method, the method is more suitable for high-throughput calculation in terms of cost and time. The method is based on the MatHub-3d database, 11993 semiconductor materials are screened from the database, the deformation potential constants of the 11993 semiconductor materials are high-throughput calculated, and the electric transport performance of 10195 semiconductor materials is high-throughput predicted by using the deformation potential constant dataset.

The invention discloses a preparation method of a thermoelectric device, and relates to the technical field of thermoelectric materials and devices.According to the material, Ag gap doping is introduced into Ag8SnSe6, an Ag2Se second phase is formed, and the electrical transport performance and the thermal transport performance are synergistically optimized: gap Ag regulates the Fermi level and activates multi-energy-band conduction, and the carrier concentration and mobility are remarkably improved; and the Ag2Se second phase enhances phonon scattering and reduces lattice thermal conductivity, so that a thermoelectricity figure of merit which is remarkably improved is obtained in a wide temperature zone range. Based on the optimized material, a thermoelectric device is further prepared, the energy conversion efficiency reaching up to 6.3% and the output power of 43.8 mW are achieved under the temperature difference of 357K, and the excellent application potential of the material in the field of thermoelectric power generation is verified.

The application discloses an intrinsic low-thermal-conductivity N-type Pb-Bi-S-based thermoelectric material and a preparation method thereof. The bulk material is N-type Pb3Bi2S6 bulk material, and the molar ratio of Pb, Bi and S is 3:2:6+x; wherein, 0.0<=x<=0.03. The preparation method provided by the application reduces vacancies through S element compensation, reduces the carrier concentration of Pb3Bi2S6, improves the carrier mobility and further improves the electrical transport performance of the material. The application uses a high-temperature melting method to obtain an ingot, grinds the ingot into uniform powder and then performs hot-pressing sintering to prepare the N-type Pb3Bi2S6 bulk thermoelectric material. In the synthesis process, a multi-section temperature zone control, optimized holding time and controlled sintering process are adopted to obtain a high-quality polycrystalline bulk material, and the material exhibits a low lattice thermal conductivity. The thermoelectric performance is improved in the room temperature to medium temperature range. The intrinsic low-lattice-thermal-conductivity N-type Pb3Bi2S6 bulk material has a rich reserve, low price and good machinability, and is expected to realize high thermoelectric performance.