88 results about "Phonon scattering" patented technology

The invention relates to a comprehensive optimization method and system for thermal conductive plastic performance in the technical field of new materials, and the method comprises the following steps: obtaining initial dispersion state data of an inorganic filler in thermal conductive plastic, and analyzing spatial distribution of filler particles through a scanning electron microscope to obtain characteristic parameters of random distribution of the filler; according to the characteristic parameters of the random distribution of the filler, calculating the heat transfer efficiency among filler particles by adopting a finite element simulation method, and determining the distribution rule of the phonon scattering phenomenon; according to the improved interface bonding strength parameters, the Monte Carlo method is adopted to simulate orientation distribution of filler particles in a matrix, and a preliminary scheme of filler orientation control is obtained; for optimization parameters of complex mold forming, a particle swarm optimization algorithm is adopted to adjust the filler proportion and distribution, and the structure configuration of the efficient three-dimensional heat conduction network is generated; and according to the structure configuration of the efficient three-dimensional heat-conducting network, the improvement degree of the heat-conducting plastic performance is analyzed and verified through a heat-conducting finite element, and final heat transfer efficiency data is obtained.

The present invention relates to the technical field of composite materials, and solves the technical problem that it is difficult to prepare a diamond / aluminum composite material with a tightly bonded interface while ensuring high thermal conductivity in the prior art. In particular, it relates to a diamond / aluminum composite material with a nano-gradient interface and a preparation method thereof. The present invention introduces a carburizing method on the basis of the magnetron sputtering method, and realizes the in-situ generation of new phases in each modified layer from the outermost metal element layer to the diamond surface through adsorption and diffusion, promotes the transformation of the metal modified elements on the diamond particle surface into carbides, and constructs a nano-gradient interface carbide layer. While the nano-scale interface layer improves the interface bonding between diamond and aluminum, it minimizes the introduced interface thermal resistance to the greatest extent. The present invention combines magnetron sputtering deposition with the carburizing method to prepare a nano-gradient multi-carbide interface layer with precisely controllable thickness, enhances the degree of interfacial diffusion reaction between diamond and aluminum, weakens the interfacial phonon scattering, and can give full play to the high thermal conductivity of diamond particles more fully.

The invention relates to a field effect transistor channel mobility determination method and device and computer equipment. The method comprises the following steps: acquiring a transfer characteristic curve of a target field effect transistor; determining a target effective electric field intensity interval corresponding to the grid voltage of the target field effect transistor according to the transfer characteristic curve of the target field effect transistor; determining the transistor body mobility of the target field effect transistor according to the body mobility model; based on the target effective electric field intensity interval, the coulomb scattering mobility, the phonon scattering mobility and the surface roughness scattering mobility of the target field effect transistor are determined according to a target coulomb scattering mobility model, a target phonon scattering mobility model and a target surface roughness scattering mobility model; and determining the channel mobility of the target field effect transistor based on a channel mobility model. According to the scheme, the performance of the device can be quickly and effectively evaluated, complex analysis testing is avoided, and the development speed of the device process is increased.

The invention relates to the technical field of heat-conducting composite materials, and discloses a heat-conducting flexible composite phase change material as well as a preparation method and application thereof. The method comprises the following steps: modifying a thermoplastic elastomer branch by using maleic anhydride as a grafting agent; performing surface hydroxylation modification on the heat-conducting filler by taking strong base as a surface modifier; and carrying out melt blending on the graft-modified thermoplastic elastomer and the phase change material, and adding the surface-modified heat-conducting filler for crosslinking to obtain the heat-conducting flexible composite phase change material. By regulating and controlling a filler-matrix microscopic interface structure, the filler-matrix interface interaction is enhanced, a heat conduction-support integrated structure is constructed, and the filler-matrix interaction improves the dispersion of the filler in the matrix and reduces the interface phonon scattering, so that the heat conduction flexible composite phase change material has good heat conduction performance; meanwhile, the material also has strong mechanical property and high energy storage density.

The invention discloses high-entropy rare earth phosphate nano ceramic powder and a preparation method thereof, the high-entropy rare earth phosphate nano ceramic powder with a xenotime structure is synthesized by combining an in-situ coprecipitation method with a low-temperature calcination process, and the average grain size of the nano ceramic powder is 45-60 nm; h3PO4 is used as a phosphorus-containing raw material and a precipitant at the same time, so that the problem of excessive impurity substances in a sample caused by introduction of other precipitants such as ammonia water and the like is avoided; and precipitates are collected in a direct evaporation manner, so that the problem of loss of part of component elements in the filtering process is completely prevented, the proportion of each element in the nano powder is consistent with the expected height, and each element is uniformly distributed. According to the method, five elements with different ion radiuses and masses are added into REPO4 crystal lattices, so that the configuration entropy and the lattice distortion degree of a sample are remarkably improved, the stability and the phonon scattering intensity of xenotime type crystal lattices in the sample are improved, and the heat conductivity of the sample is reduced.

The invention provides an inorganic salt / carbon aerogel composite phase change material and a preparation method thereof, and belongs to the technical field of phase change material preparation. The composite phase change material is prepared through electrochemical stripping, HF etching, freeze drying, high-temperature carbonization and vacuum impregnation. The electrochemical exfoliated graphene and the TiC / carbon aerogel are combined together through self-assembly to construct a heterogeneous interface and increase effective nucleation sites, so that the energy potential barrier of phonon scattering and nucleation is reduced, and the thermal conductivity is improved while the degree of supercooling is reduced; the aerogel adsorbing the inorganic salt phase change material forms hydrogel with a compact network through self-assembly, crystallization of the hydrated salt is promoted, and the hydrated salt inorganic phase change material is limited in a porous material by utilizing the confinement effect of a nano material, so that the hydrated salt inorganic phase change material is not easy to leak, and relatively good latent heat is maintained.

The present invention provides a gallium nitride-based light-emitting diode epitaxial structure, a preparation method thereof, and an LED chip. In the epitaxial structure, a multi-level electron-phonon scattering structure, a stepwise increase in the bandgap width of the quantum well layer in the multi-quantum well barrier layer, and an InGaN step structure are designed to suppress electron leakage in different situations, targeting electron ballistic transport, electron acceleration caused by the quantum Stark effect structure in the quantum well, and hot electron transition. This effectively improves the external quantum efficiency under high current.

The invention discloses a rock high-temperature heat conductivity coefficient prediction method, device and equipment and a storage medium, and the method comprises the steps: building a high-temperature mineral heat conductivity coefficient model based on a phonon scattering theory, and determining the heat conductivity coefficient of each mineral in a multiphase rock mixed model through the high-temperature mineral heat conductivity coefficient model; determining the number of cracks in the multi-phase rock mixed model at high temperature by using a fracture mechanics theory; constructing a series-parallel thermal resistance model of a basic unit in the multiphase rock mixing model based on the number of the cracks; and predicting the rock high-temperature heat conductivity coefficient of the multiphase rock mixing model through the effective medium theory model and the series-parallel thermal resistance model. According to the method, the heat conductivity coefficient of each mineral in the multiphase rock mixed model is determined based on the phonon scattering theory, and the fracture influence is represented by using the fracture mechanics theory and the series-parallel thermal resistance model, so that compared with the prior art, the reliability and the accuracy of predicting the heat conductivity coefficient of the rock at high temperature are improved.

The invention discloses a power semiconductor module residual life prediction method and device and a medium, and relates to the technical field of semiconductor life prediction, and the method comprises the steps: enabling collected material lattice parameters and thermodynamic working condition data to generate a transport data set through a molecular dynamics simulation method, and generating an inverted space group velocity tensor field according to the transport data set; generating a thermodynamic entropy change index according to the inverted space group velocity tensor field; performing time sequence accumulation analysis based on thermodynamic entropy change indexes, and outputting a phonon entropy change feature sequence; extracting a statistical feature subset and a dynamic gradient subset from the phonon entropy change feature sequence; constructing a pulse neural network and inputting the phonon entropy change feature sequence to generate an operation function; calling a transport equation and initializing based on the statistical feature subset to generate an initial transport equation; according to the method, the collision term of the transport equation is dynamically reconstructed through the pulse neural network, accurate modeling of the phonon scattering nonlinear effect is achieved, and the problem of mismatching of the heat transport model under the variable working condition is solved.

This invention discloses a method for preparing a side-chain liquid crystal photosensitive resin monomer with photo-oriented and thermally anisotropic properties and its application in 3D printing. Using 2,2-di(hydroxymethyl)propionic acid, isophorone diisocyanate, and hydroxyethyl methacrylate as raw materials, a side-chain liquid crystal photosensitive resin monomer is prepared and applied to 3D printing resin. Under the action of a 3D printing laser, the liquid crystal units in the side-chain liquid crystal photosensitive resin monomer of this invention form an oriented structure in the laser direction, allowing heat flow to be conducted along the oriented structure and effectively suppressing phonon scattering, thus exhibiting thermal anisotropy. Simultaneously, the side-chain liquid crystal photosensitive resin monomer with photo-oriented and thermally anisotropic properties of this invention exhibits good mechanical properties after 3D printing.

The invention relates to a chiral perovskite semiconductor circular polarization luminescence enhancement structure and a preparation method and application thereof, and belongs to the technical field of chiral photoelectric semiconductor materials and micro-nano devices. According to the structure, two layers of chiral perovskite semiconductor nanosheets are stacked through a controllable torsion angle to form a homojunction, and the torsion angle ranges from 0 degree to 90 degrees. According to the present invention, by adjusting the interlayer torsion angle, the continuous regulation and the significant enhancement of the circular polarization light emitting polarization degree are achieved, and especially during the parallel stacking (0 degree torsion angle), the circular polarization light emitting polarization degree is improved by 3 times compared with the single nanosheet and the vertical stacking (90 degree torsion angle). The enhancement effect is derived from inter-layer coupling dependent on a torsion angle, spin selective charge transfer is promoted, exciton binding energy is enhanced, and electron-phonon scattering is inhibited. The invention provides an effective way for regulating and controlling the polarization degree through the torsion angle, and is suitable for the fields of circular polarization luminescent devices, spin optoelectronic devices, quantum information processing and the like.

The invention belongs to the technical field of thermoelectric materials, and provides a composite P-type bismuth telluride-based material and a preparation method thereof in order to improve the thermoelectric performance of the thermoelectric materials, the composite P-type bismuth telluride-based material comprises a P-type bismuth telluride matrix with the chemical formula being Bi < 0.5 > Sb < 1.5 > Te < 3.2 > and a compound used for compounding, the chemical formula of the composite compound is selected from one or more of Cu2GeSe3, Ag8GeTe6 and Ag5Te3, and the chemical formula of the P-type bismuth telluride matrix is Bi < 0.5 > Sb < 1.5 > Te < 3.2 >. And the usage amount of the composite compound is 0.04-0.1% of the mass of the P-type bismuth telluride matrix. According to the P-type bismuth telluride-based composite material provided by the invention, crystal boundary, second phase and other defects are introduced after compounding to enhance phonon scattering, so that the lattice thermal conductivity is effectively reduced, and finally, the improvement of the material performance is realized by optimizing the carrier concentration and reducing the lattice thermal conductivity.

The present invention relates to a coating material, a preparation method thereof and an application. The preparation method of the coating material includes: S1. preparing rare earth phosphate powder by a sol-gel method; S2. preparing aluminum tantalate powder by a solid-phase sintering method; S3. mixing the rare earth phosphate powder and the aluminum tantalate powder, and performing spark plasma sintering to obtain the coating material. In the present invention, a rare earth phosphate second phase is introduced into the main phase of the aluminum tantalate ceramic, and thus grain boundary phonon scattering and second-phase toughening mechanisms are introduced. By refining the grains, the proportion of grain boundaries is increased, the overall phonon scattering is enhanced, the thermal conductivity of the system is further reduced, and a higher heat insulation gradient is provided. Before the crack propagates, it is necessary to first overcome the internal residual strain energy of the dual-phase ceramic itself. At the same time, due to the relatively high thermal expansion coefficient of the rare earth phosphate, a compressive stress is generated on the lattice of the main phase in a high-temperature working environment, which can inhibit the generation and propagation of cracks, thereby achieving the purpose of toughening and effectively improving the performance stability of the coating material.

According to the gallium nitride-based semiconductor laser with the gradually-changed polarized optical phonon energy waveguide layer, a fitting curve of In ion strength distribution or In atom concentration distribution of an upper waveguide layer and a lower waveguide layer is tested through SIMS, and a fitting curve of polarized optical phonon energy distribution meets any function distribution of Log3P1, Lop2P2 and Biphase. The spatial continuous regulation and control of the phonon energy of the optical field are realized, so that the LO phonon energy is continuously and gradually changed along the propagation direction, the phonon energy gradient is formed, the LO phonon scattering is improved, the inelastic scattering and energy relaxation of carriers and LO phonons are inhibited, the carrier transportation and phonon scattering are optimized, the service life of the carriers and the gain retention time are prolonged, and the optical field performance is improved. According to the invention, the threshold current density is reduced, the thermal stability of the laser is improved, the use power and the use temperature of the laser are improved, meanwhile, the phonon energy valley value is matched with the quantum well gain peak, the scattering loss is inhibited, additional scattering caused by phonon energy mutation is avoided, the light field limitation is enhanced, and the slope efficiency is improved.

The application relates to a method for calculating the optical properties of a thermal control material in the mid-infrared waveband, and belongs to the field of thermal control material design of a spacecraft. The application aims to solve the problem that the existing mainstream calculation ideas are mainly focused on the related calculation in the sunlight waveband, and the calculation and research on the optical properties of the material in the mid-infrared waveband are relatively less. The method comprises the following steps: establishing a unit cell model, optimizing the structure model with high precision through a step-by-step optimization method, calculating a second-order force constant matrix, a BORN effective charge, a dielectric constant tensor, a third-order force constant matrix and a three-phonon scattering rate, determining an optical phonon vibration mode of a Brillouin zone center with infrared activity, calculating the dielectric function of the material according to a Lorentz oscillator model, and further calculating the refractive index and extinction coefficient of the material. The application significantly improves the calculation precision and efficiency of the optical properties of the thermal control material in the mid-infrared waveband, provides a reliable theoretical basis for the research and development of new materials, and can effectively reduce the experimental cost and shorten the research and development period.

The invention relates to the technical field of thermoelectric materials, in particular to a Bi2SeS2-based thermoelectric material and a preparation method and application thereof, the Bi2SeS2-based thermoelectric material takes Bi2SeS2 as a matrix, and the matrix is doped with a copper element and silicon carbide as a nano composite phase. According to the invention, the electric transport performance and the heat transport performance of the material are synchronously optimized through a synergistic strategy of Cu doping and SiC nano-compounding; cu doping effectively improves the carrier concentration and conductivity, SiC nano-compounding introduces a large number of nano-interfaces, the SiC nano-compounding and the point defects generated by Cu doping jointly construct a point defect-nano-interface multi-scale phonon scattering mechanism, and the lattice thermal conductivity is remarkably reduced. Moreover, the process for preparing the Bi2SeS2-based thermoelectric material is simple, the cost is low, the thermoelectricity of the Bi2SeS3 material at 773 K is successfully improved to 0.83, and a reliable way is provided for industrial application of the Bi2SeS2-based thermoelectric material.

The invention provides an electron source module and an electron beam direct writing machine. The electron source module comprises an array type electron source substrate (1), and a plurality of electron emission units (2) are formed on a first main surface (1-1) of the array type electron source substrate; and the local temperature control mechanism (3) is in contact with the array type electron source substrate (1) and controls the temperature of the array type electron source substrate (1) to be not higher than a preset temperature value. The local temperature control mechanism is arranged to control the temperature of the array type electron source substrate in the electron source module, so that the phonon scattering level can be greatly reduced.

The invention relates to the technical field of electrical contact materials, in particular to a copper-based electrical contact composite material for enhancing electric conductivity and heat conductivity through cobalt-mediated interface engineering and a preparation method of the copper-based electrical contact composite material. (2) adding the deoiled copper powder and a conductive polymer into an initiator solution or a buffer solution; (3) filtering and collecting the polymer and the cobalt-coated copper powder; (4) drying the collected composite material precursor; and (5) carrying out hot pressing or pressing sintering to obtain the modified copper-based electrical contact material. A conductive polymer and cobalt ions are complexed and assembled on the surface of copper powder, then high-temperature sintering is performed to obtain the copper-based composite material, and cobalt catalyzes formation of high-quality graphene; the heteroatom-doped graphene is prepared through high-temperature carbonization of the conductive polymer, and the carrier concentration and the interface energy band structure of the material are optimized; and the cobalt bridging copper-carbon interface reduces electron and phonon scattering and improves the electrical conductivity and thermal conductivity of the composite material.

The application discloses a method for calculating lattice thermal conductivity of rare earth oxide based on first principle. The method comprises the following steps: establishing a crystal structure model of the rare earth oxide, and constructing a supercell model after structure optimization; calculating second-order interatomic force constants by using a first principle method to obtain a phonon dispersion relation, and calculating third-order interatomic force constants to obtain a phonon scattering rate; solving the lattice thermal conductivity by using a Wigner transport equation, wherein the lattice thermal conductivity comprises a particle contribution described by a diagonal item of a phonon spectral function and a wave contribution described by a non-diagonal item, and the two are added to obtain a thermal conductivity contribution of each phonon mode; and integrating and summing all phonon modes in a Brillouin zone to output a frequency, temperature and direction dependence of the total lattice thermal conductivity. The application can accurately predict the lattice thermal conductivity and anisotropy of the rare earth oxide in a wide temperature range without an empirical parameter.

The invention discloses a p-type copper doped antimony bismuth tellurium thermoelectric material, a preparation method, a module and a system, and belongs to the technical field of thermoelectric materials. The chemical formula of the material is Bi < 0.5 > Sb < 1.5 > Te < 3 > Cu < x >, wherein x is equal to 0.0025. A trace amount of copper element is accurately doped into a Bi0. 5Sb1. 5Te3 matrix, so that the carrier concentration is remarkably improved, the bipolar effect is inhibited, and meanwhile, the lattice thermal conductivity is effectively reduced by utilizing point defects and the phonon scattering effect of second-phase CuTe, so that collaborative optimization of electrical and thermal properties is realized. The average dimensionless thermoelectric figure of merit (ZT) of the material in a temperature zone of 30-100 DEG C is up to 1.46, which is superior to that of the existing commercial material. The preparation method combines vacuum melting, ball milling and spark plasma sintering (SPS) processes, and is simple and convenient in process and high in repeatability. And further high-pressure torsion (HPT) post-treatment can further refine the grains and reduce the heat conductivity. The material is particularly suitable for an energy recovery and self-energized monitoring system of converter valve low-temperature waste heat.

The invention relates to a GCM / bismuth telluride-based composite thermoelectric material and a preparation method and application thereof, the structural formula of the composite thermoelectric material is shown as Gd (Co < 0.433 > Mn < 0.567 >) < 2 > / Bi < 0.3 > Sb < 1.7 > Te3, and the composite thermoelectric material is obtained by introducing a magnetic second phase GCM (Gd (Co < 0.433 > Mn < 0.567 >) < 2 >) into a bismuth telluride matrix Bi < 0.3 > Sb < 1.7 > Te3. Compared with the prior art, due to the introduction of the magnetic second phase GCM, a generated built-in magnetic field and magnetic scattering, the mobility is reduced, the Seebeck coefficient is increased, due to the diffusion of the GCM, the carrier concentration is increased, the prepared composite thermoelectric material has high electrical performance, meanwhile, due to the introduction of the GCM, phonon scattering is increased, and the performance of the composite thermoelectric material is improved. According to the GCM / bismuth telluride-based composite thermoelectric material, the crystal lattice thermal conductivity of the composite material is effectively reduced, the GCM / bismuth telluride-based composite thermoelectric material has high conductivity, low thermal conductivity and high thermoelectric performance, and the average zT value of the composite material is increased by 39% within the temperature range of 300-500 K. Wide application prospects are realized.

This invention relates to the field of semiconductor device technology, specifically to a semiconductor laser element with a two-dimensional phonon and three-dimensional charge transport layer. The semiconductor laser element has a two-dimensional phonon and three-dimensional charge transport layer between the active layer and the upper waveguide layer, and between the active layer and the lower waveguide layer. This layer is a two-dimensional moiré superlattice structure composed of one or more of SnSe, AgSbT2, SnTe, ZrNiSn, Bi2Te3, and NbFeSb. This layer promotes electronic hybridization, introduces local strain modulation of phonon vibrations, enhances atomic order, reduces phonon scattering, and simultaneously enhances phase transition-induced electron orbital overlap and two-dimensional phonon and three-dimensional charge transport. It also reduces the valence band order of the laser, enhances carrier localization, hole transport, and stimulated emission of the laser element, lowers the excitation threshold of the laser element, enhances bipolar conductivity, improves continuous oscillation below room temperature, enhances the confinement factor and peak gain, reduces the laser voltage, and improves the optical power and slope efficiency of the laser element.

The invention relates to a multi-element rare earth doped HfO2 thermal barrier coating material and a preparation method thereof, and belongs to the technical field of thermal protection coatings. The thermal barrier coating material is prepared from Gd2O3, Yb2O3, Y2O3 and HfO2, wherein the Gd2O3, the Yb2O3, the Y2O3 and the HfO2 are The thermal barrier coating material is of a single c-phase structure. The raw material powder is ground to obtain mixed powder, the mixed powder is sintered after being ground and compacted, and finally the coating material is obtained through grinding and screening. The rare earth elements Gd < 3 + >, Yb < 3 + > and Y < 3 + > with large ion radiuses are doped to replace tetravalent Hf4 < + > crystal lattice positions, a large number of point defects are formed in crystal lattices, and a large number of oxygen vacancies are generated due to the charge balance effect, so that phonon scattering heat transfer is remarkably enhanced, and the multi-element rare earth doped HfO2 thermal barrier coating material has low thermal conductivity.

The invention discloses a mullite aerogel composite material with large size, high strength, wide temperature range and low thermal conductivity and a preparation method thereof. According to the composite material, a high-temperature-resistant fiber preform of which the surface is modified with a nano layer is used as a macroscopic framework, and the macroscopic framework and a silicon-aluminum molecular sieve / mullite nano matrix are chemically bonded to form a'macroscopic-mesoscopic-nano 'multistage synergistic enhancement structure. The preparation method comprises the following steps: growing an interface layer on the fiber surface in situ through a hydrothermal method; preparing silicon-aluminum composite sol; impregnating a fiber preform and gelling; and performing aging, supercritical drying and heat treatment to obtain a final product. Through an infrared shielding effect and a phonon scattering effect of a multi-heterogeneous interface, high-temperature radiation heat transfer and solid heat conduction are remarkably inhibited, so that the material has high strength, low heat conduction and 1500 DEG C high-temperature stability while keeping low density and high specific surface area, and preparation of a large-size complete block is successfully realized; the method has great application prospects in the fields of high-temperature heat insulation, industrial high-temperature catalysis or adsorption and the like.

The application belongs to the technical field of composite film materials, and particularly relates to a boron nitride nanosheet-aramid nanofiber composite film and a preparation method thereof. 2+ / SA crosslinking solution; hexagonal boron nitride is added into the Ca 2+ / SA crosslinking solution, and pre-infiltration is realized through magnetic stirring to obtain a pre-infiltrated SA / BNNS solution; the pre-infiltrated SA / BNNS solution is subjected to ball milling and washing to obtain a BNNS / water suspension; the BNNS / water suspension is mixed with an ANF / DMSO dispersion to obtain a BNNS / ANF mixed solution; the BNNS / ANF mixed solution is subjected to vacuum filtration, drying and hot-pressing treatment to obtain the boron nitride nanosheet-aramid nanofiber composite film; and the application improves the interfacial phonon scattering between BNNS, so that the interfacial density of the material is lower and the contact area of the interface is larger, thereby improving the thermal conductivity of the composite film.

The application relates to the technical field of pesticide controlled release, in particular to a preparation and application of a pesticide controlled release carrier, which comprises the following raw materials: a natural polymer matrix, a temperature-sensitive material, a light-heat material, an acid solvent, an alkali solvent and a pesticide. Chitosan (CS) is used as a natural polymer material which is widely sourced, non-toxic and naturally degradable, the spherical gel has the advantages of simple preparation, controllable particle size and rich surface chemical bonds, and is widely applied to drug adsorption and delivery. The introduction of nanoparticles can endow the polymer hydrogel with unique functional characteristics. Diamond nanodiamond (DND) is a nanoscale carbon allotrope which is composed of a sp3 carbon diamond core and a reconstructed sp2 carbon surface layer, can absorb light in the ultraviolet, visible and near-infrared regions in the form of phonon scattering / lattice vibration and convert it into heat, and has excellent photo-thermal performance. Poly-N-isopropyl acrylamide (PNIPAm) is a temperature-sensitive material which is in a sol state at room temperature and is converted into a gel state when close to body temperature.

The application relates to the technical field of thermoelectric materials, in particular to a MnTe alloying-regulated AgSbTe2-based thermoelectric material and preparation and application thereof. Through the MnTe alloying strategy, local composition fluctuation and lattice distortion are induced in the AgSbTe2 matrix, sub-micron scale Ag2Te second phases and Mn-Te enrichment regions are formed, intrinsic Ag / Sb cation disorder is combined, a multi-scale phonon scattering network is constructed, the propagation of phonons with different frequencies is effectively inhibited, the lattice thermal conductivity is significantly reduced, meanwhile, through carrier concentration optimization and Fermi level regulation, the Seebeck coefficient is effectively improved while the reasonable electrical conductivity is maintained, the power factor of the material is obviously improved, and therefore, the thermoelectric performance of the MnTe solid solution sample is significantly improved.

The invention relates to a method for predicting anisotropic thermal conductivity of a two-dimensional material nanobelt. The method comprises the following steps: (1) respectively establishing molecular dynamics thermal transport models of a graphene nanobelt and a black phosphorus nanobelt consisting of a hot area and a cold area; (2) executing molecular dynamics simulation and data processing: (1) comparing in-plane thermal conductivity data at different torsion angles to determine the in-plane thermal conductivity anisotropy of the two-dimensional material; (2) analyzing a phonon dispersion curve, and revealing a dependency relationship of in-plane thermal conductivity on a transmission direction; (3) researching the influence of different system lengths on the in-plane thermal conductivity; and (4) respectively calculating in-plane heat conductivity, heat flow and phonon number changes at different system temperatures, and analyzing the influence of the temperature on the in-plane heat conductivity and the internal mechanism of the in-plane heat conductivity by comparing the heat flow and in-plane heat conductivity changes at different system temperatures and combining a phonon scattering mechanism. According to the method, an optimization strategy is provided for thermal management of the nano device by analyzing thermal conductivity changes under different thermal transmission directions, system sizes and temperature conditions.

The invention relates to the technical field of functional materials, in particular to an n-type Mg3Sb2-based thermoelectric material with adjustable Bi content and a preparation method and application thereof, and the chemical structural formula of the Mg3Sb2-based thermoelectric material is Mg < 3.2 > Sb < 1.5-x > Bi < 0.49 + x > Te < 0.01 >. The composite material is prepared by combining vacuum solid-phase sintering with rapid hot pressing and subsequent annealing processes; by accurately regulating and controlling the content of the Bi element and utilizing the solid solution effect formed by replacing Sb with Bi, the conductivity and the power factor of the material are remarkably improved, meanwhile, phonon scattering is effectively enhanced, and the lattice heat conductivity is greatly reduced, so that collaborative optimization of electroacoustic transport performance is achieved, and finally the thermoelectric figure of merit ZT of the material is greatly improved in a medium-temperature region; and the peak value ZT can reach 1.1 or above. The material is simple and efficient in preparation process, the obtained sample is high in purity and good in compactness, large-scale industrial production is facilitated, and the material is suitable for thermoelectric energy conversion application.

The invention discloses an AgInTe2 semiconductor thermoelectric material containing a hole structure and a preparation method and application thereof, and belongs to the technical field of new energy material preparation. By adjusting the technological process of mechanical alloying and specific parameters of spark plasma sintering, the size (nanoscale), the number (the porosity is about 8-12%) and distribution of the holes can be accurately controlled, and optimization of thermoelectric performance is achieved. The hole structure significantly enhances phonon scattering, reduces lattice thermal conductivity by about 30-40%, increases carrier scattering anisotropy, increases Seebeck coefficient, and maintains high conductivity. The method adopts ball milling and plasma sintering, does not need high-temperature melting and long-time annealing, is simple and efficient, and is suitable for industrial production. The porous structure of the material can relieve thermal stress, is high in stability and excellent in performance in a wide temperature range, the surface area of the pores is increased, the material can be conveniently compounded with other materials, the performance is optimized, the mechanical and machining performance is improved, and the material is suitable for the fields of industrial waste heat power generation, automobile exhaust waste heat recovery and the like.