2529 results about "Crystal growth" patented technology

Crystal growth systems with a baffle are provided. In one example, a crystal growth system for growing crystalline material, the crystalline material including silicon carbide, includes a seed holder configured to hold a silicon carbide seed crystal. The seed crystal provides a growth surface for growth of the silicon carbide crystalline material. The system includes a crucible at least partially defining a crystal growth chamber. The system includes a source material. The system includes one or more baffles within the crystal growth chamber and spaced apart from the source material. The one or more baffles include one or more apertures defined through the one or more baffles. The baffle includes a long dimension that is non-perpendicular to the growth surface of the seed crystal.

The invention belongs to the technical field of silicon carbide single crystal materials, and particularly relates to a growth device of large-size silicon carbide single crystals and a preparation method of the silicon carbide single crystals, porous graphite cylinders are arranged in a powder area of the growth device of the large-size silicon carbide single crystals, and the porous graphite cylinders are distributed along the edge of the powder area to the center in a stepped mode. The height is gradually increased from the edge to the center; a plurality of layers of stacked graphite pore plates are arranged at the top of the powder area, the upper end parts of the porous graphite cylinders are flush with the upper surfaces of the corresponding layers of graphite pore plates, and the porous graphite cylinders penetrate through the graphite pore plates, so that a continuous gas phase transmission channel from the powder area to the crystal growth area is formed. According to the invention, the plurality of porous graphite cylinders are arranged in the silicon carbide raw material area in a stepped manner, so that the temperature field distribution of the raw material area is stabilized, the gas phase layout is optimized, impurities in gas phase components are filtered, and the defects of microtubes, inclusions, dislocation and the like in crystals are improved.

The invention relates to the field of Czochralski single crystal furnace crystal bar production, in particular to a Czochralski single crystal shouldering control system, which comprises a CCD (Charge Coupled Device) information acquisition unit, a computer information storage processing unit and a PLC (Programmable Logic Controller) growth regulation unit, the computer information storage processing unit receives information acquired by the CCD information acquisition unit, then performs cloud data storage processing and outputs single crystal shoulder information of a corresponding time node to the PLC growth regulation unit, and the PLC growth regulation unit performs shouldering cooling amount control, automatic crucible lifting intervention in the shouldering process, automatic intervention control of equal-diameter liquid opening distance and pulling speed control. According to the method, the problems of shouldering line breakage and equal-diameter head line breakage caused by the fact that automatic regulation of the current shouldering pulling speed does not conform to actual growth of crystals are solved, and the consistency of field process parameter management is improved.

The invention discloses a zinc foil preparation method for inhibiting zinc dendritic crystal growth, which comprises the following steps: carrying out laser texturing treatment on the surface of a pure zinc foil to generate a high-density ordered micro-pit array structure on the surface of the zinc foil, thereby greatly increasing the number of active sites on the surface of the zinc foil and eliminating the defects of scratches, pits and the like generated by the zinc foil; and carrying out alloying treatment on the zinc foil and a CuCl2 solution to generate a CuZn5 alloy layer so as to obtain the zinc foil for inhibiting dendritic crystal growth. The high-density ordered micro-pit array structure on the surface of the zinc foil eliminates the structural defects of the zinc foil, the increase of active sites and the introduction of the CuZn5 alloy layer can significantly reduce the desolventizing energy barrier in the charge transfer process and promote the Zn deposition / dissolution kinetics on the surface of the negative electrode, so that few by-products are formed in the treated negative electrode, and the service life of the negative electrode is prolonged. Therefore, the cycle performance of the treated zinc foil after the zinc foil forms a button cell is greatly improved, the service life of the zinc foil is obviously prolonged, and the economic benefit is particularly obvious.

The invention relates to the technical field of crystal furnace control parameter optimization, and discloses a crystal furnace control parameter optimization method and system based on deep learning, and the method comprises the following steps: 1, obtaining temperature value data in a crystal furnace heating process, and analyzing the temperature value data to obtain a crystal growth state characterization value; and 2, comparing the crystal growth state characterization value with a crystal growth state characterization threshold value to generate a crystal growth state abnormal signal. The temperature value data of the crystal furnace is obtained and compared with the temperature threshold range, whether the temperature is abnormal or not is judged, the temperature abnormal data is obtained, and the crystal state characterization value is calculated based on the obtained temperature abnormal data, so that the crystal growth state in the crystal furnace can be indirectly judged through the temperature of the crystal furnace. The crystal growth state condition is judged through the crystal growth state characterization value, and a crystal growth state normal signal or a crystal growth state abnormal signal is generated.

The invention discloses a power battery thermal runaway fault detection method and system based on multi-source parameters, and belongs to the technical field of battery management, and the method comprises the steps: inputting a high-frequency signal generated by a signal generator to a positive electrode feed point of a battery cell, connecting a coaxial line to a positive electrode, and grounding a negative electrode to form a grounding loop; the collected dendritic crystal reflection signals are analyzed, a quantitative correlation model is established, the growth condition of dendritic crystals is analyzed according to the quantitative correlation model, and preliminary early warning is carried out; electrochemical parameters and auxiliary parameters of the battery cell are collected, and cross validation is carried out on the electrochemical parameters and the auxiliary parameters and preliminary early warning of dendritic crystals; and establishing a dynamic risk and grading response mechanism, dividing the risk into different grades, and setting corresponding response measures. In the implementation process of the technical scheme provided by the invention, by combining dendritic crystal growth prediction and electrochemical parameter analysis, accurate monitoring of the internal state of the power battery is realized, the timeliness and accuracy of thermal runaway early warning are effectively improved, and safe and stable operation of a battery system is ensured.

The invention provides a silicon carbide crystal growth process which comprises the following steps: A) dividing the interior of a crucible into seven loading areas, namely an F area, a D area, a B area, an A area, a C area, an E area and a G area which are adjacent in sequence by adopting graphite partition plates, filling silicon carbide powder in each loading area, and placing the graphite partition plates perpendicular to the bottom surface of the crucible; the particle size of the silicon carbide powder is 10-80 meshes; and B) fixing a seed crystal on the top of the crucible filled with the silicon carbide powder, and growing the silicon carbide crystal by adopting a PVT method. By optimizing the charging process, the uniformity and the utilization rate of sublimation gas of the powder in the growth process can be improved, the stability of a temperature field in a furnace is facilitated, the probability of crystal phase change is reduced, crystal defects (phase change, polycrystal, dislocation and the like) are reduced, and thus the crystal quality is improved.

The invention relates to the field of crystal preparation, in particular to a production device and a preparation method of monocrystalline silicon, the monocrystalline silicon and an insulated gate bipolar transistor. The apparatus for producing monocrystalline silicon comprises: a crucible for placing and melting a raw material; the heating module is arranged around the crucible and comprises a fixed heater at the upper part and a movable heater at the lower part, and the movable heater moves along the lifting direction of the crystal bar so as to accurately control the crystal growth temperature gradient and the oxygen diffusion transmission mode at different stages of crystal growth; and the magnetic field module is used for applying an asymmetric hook-shaped magnetic field in the crystal growth process so as to inhibit convection of raw materials in the crucible, reduce the oxygen concentration and improve the radial uniformity of oxygen. According to the technical scheme, on the basis of 300mm N-type monocrystalline silicon, under low oxygen (lt; 5ppma), ROGlt; and on the basis of 10%, the target of low potential type defect density can also be achieved, so that the high-quality requirements, including ultralow oxygen content, low defect density and the like, of an IGBT (Insulated Gate Bipolar Translator) on a silicon single crystal substrate are met. The efficient preparation of the ultralow-oxygen N-type silicon single crystal is realized by combining a heater with a novel structure with a CUSP magnetic field technology and matching with crystal pulling process parameter optimization. According to the silicon single crystal prepared by the method, the performance and the reliability of an IGBT (Insulated Gate Bipolar Translator) can be remarkably improved, the production cost is reduced, and the requirements of modern power electronic devices on high-performance silicon-based materials are met.

The invention relates to a temperature regulation and control method for a sapphire crystal growing furnace, the temperature regulation and control method is applied to the sapphire crystal growing furnace, the sapphire crystal growing furnace comprises a heat preservation structure, the heat preservation structure comprises at least two heat preservation units, and the heat preservation units are annular and stacked to form a cylindrical heat preservation structure; a medium cavity is formed in each heat preservation unit and used for containing a gas heat preservation medium. The number of the circulating units is the same as that of the heat preservation units, the circulating units are in one-to-one correspondence with the heat preservation units, and the circulating units are correspondingly connected with one heat preservation unit; in the first stage of crystal growth, gas heat preservation media with the same content are injected into the medium cavities of all the heat preservation units; in the second crystal growth stage, the content of the gas heat preservation medium in the medium cavity is gradually reduced in the direction from bottom to top. The technical problem that the sapphire crystal growth quality is poor is solved, and the technical effect of improving the sapphire crystal growth quality is achieved.

The invention provides a gallium nitride thin film and a growth method of a quasi Van der Waals epitaxial gallium nitride thin film. The method comprises the following steps: step 101, transferring or directly growing on a substrate to obtain a two-dimensional material layer; step 102, processing the two-dimensional material layer by adopting a plasma enhanced MOCVD (Metal Organic Chemical Vapor Deposition) method; and step 103, performing quasi Van der Waals epitaxial growth of gallium nitride on the processed two-dimensional material layer to form the gallium nitride single crystal film. The invention also provides the gallium nitride film prepared by the method. According to the method provided by the invention, the quasi van der Waals epitaxy is carried out by using the plasma enhanced MOCVD, and plasma treatment and epitaxial growth can be completed in situ. Compared with MBE equipment, the method has the characteristics of high growth speed and large growth quantity in quasi Van der Waals epitaxy; compared with traditional MOCVD, the possibility that the two-dimensional material is polluted in the substrate transfer process can be reduced, and the crystal growth quality is improved.

The invention relates to the technical field of crystal growth, and discloses a machine learning-based crystal growth process optimization control system and method, and the system comprises a difference detection module which is used for obtaining a crystal contour of a current crystal growth image, and obtaining a crystal growth difference degree; the model establishment module is used for acquiring historical crystal growth data and establishing a growth morphological parameter prediction model according to the historical crystal growth data; the morphology prediction module is used for inputting the current crystal growth difference degree into a growth morphology parameter prediction model to obtain a predicted growth morphology parameter of the current crystal; and the temperature setting module is used for determining the temperature required by growth according to the predicted growth morphological parameters of the current crystal and correcting the temperature required by growth according to the historical crystal growth data. The growth morphology of the crystal is predicted by establishing a growth morphology parameter prediction model, so that the optimal temperature required by crystal growth is obtained, and the crystal growth quality is improved.

The invention belongs to the technical field of crystal materials, and particularly relates to a controllable growth device and method for a large-size perovskite structure iodine copper cesium single crystal. The designed growth equipment mainly comprises a growth system, a temperature control system and an anti-solvent diffusion system. The method for growing the large-size iodine-copper-cesium single crystal by adopting the temperature-control and speed-control anti-solvent diffusion method comprises the following steps: in the growth process of the iodine-copper-cesium crystal, carrying gas generated by a gas generator carries an anti-solvent into a grower through an anti-solvent device, and controlling the content of the anti-solvent entering a solution by adjusting the flow speed of the carrying gas, and further controlling the supersaturation degree of the growth liquid and carrying out crystal growth. According to the method, the crystal growth can be accurately controlled in the crystal growth process, the problems of small crystal size and poor quality of a volatilization method are solved, the problems of large corrosion, long growth period and the like of an acid solution used in a traditional cooling method are solved, and the problem of crystal cracking caused by large temperature difference and large internal stress after the growth is completed is avoided.

The invention provides a method for preparing an iron-based superconducting material single crystal in a microgravity environment, and belongs to the field of superconducting materials. The method specifically comprises the following steps: carrying out a microgravity crystal growth experiment in a high-temperature experiment cabinet of a space station, putting a solid-phase sintered or pre-melted rod-like raw material into a furnace body, heating and melting, then slowly solidifying, and finally growing the iron-based superconducting material single crystal with large size and extremely low defect density.

The invention discloses an automatic quality monitoring system based on a nickel hydrazine nitrate manufacturing technology, and relates to the technical field of nickel hydrazine nitrate manufacturing. The system has the functions of integrating a multi-wavelength filter wheel module, a process stability monitoring module and the like, and full-parameter real-time monitoring of the reaction process is realized. A Savitzky-Golay filtering algorithm is adopted to calculate a reaction rate, an XGBoost model is combined to predict a quality grade, and a hierarchical control strategy is designed to cope with different quality risks. And the risk assessment module simulates a crystal growth process by using a reaction kinetic model, identifies key risk factors, constructs a risk matrix to divide production areas, and generates an assessment report. Spectral data are corrected through a three-dimensional compensation matrix, the type of a quality problem is judged by adopting a double-layer fusion algorithm, and closed-loop control is realized in combination with a PID controller and an emergency emission program. A monitoring interface displays key parameters and early warning information in real time, dynamic adjustment of process parameters is supported, the production process is optimized, and the product quality and the production efficiency are improved.

The invention provides a crystal growth device and a crystal growth method, and solves the technical problems of low wafer utilization rate, low crystal growth speed, low efficiency, poor uniformity and the like in the existing chip manufacturing process. According to the invention, a traditional cylindrical ampoule structure is abandoned, and the annular ampoule design is innovatively adopted, so that the crystal grows into an inner hollow cylinder shape which is highly matched with the specification of a target wafer; the heater is arranged on the inner side of the ampoule, a traditional outer side heating mode is replaced, and heat is intensively acted on crystals in cooperation with an adjusting center of a heat preservation material during crystal growth, so that heat loss is reduced; the periphery of the heater is made of heat insulation materials, heat radiation leakage is effectively restrained, meanwhile, the ampoule supporting structure is adjusted, and the whole device is simple, low in cost and light in weight.

The present invention relates to the technical field of gallium oxide crystal growth, and in particular to a thermal field structure and a device and method for preparing gallium oxide single crystals based on a guided mold method. The present invention changes the inner cavity at the bottom of the thermal field structure from a circular cavity to an elliptical cavity, so that the thermal field structure in the width direction of the mold extends toward the mold side, thereby improving the thermal insulation of the thermal field structure on both sides of the mold, and then prompting the mold core to move closer to the edges on both sides of the mold, ensuring the constant temperature gradient on the mold surface during the shouldering process of the crystal, avoiding temperature differences, and improving production efficiency. In addition, since the extended thermal field structure will make the air inlet airflow closer to the mold surface, resulting in the problem of cold airflow directly blowing the crystallization area on the mold surface, a drainage port is added below the air inlet to guide the cold airflow to the crucible position, thereby ensuring the effect of the mold core moving closer to the edges on both sides of the mold.

The invention relates to the field of ZIF-8 nanocrystals, in particular to a thermostable ZIF-8 nanocrystal and a one-pot synthesis method thereof. The thermostable ZIF-8 nanocrystal is prepared from the following substances in parts by weight: 10 to 15 parts of 2-methylimidazole; 4-8 parts of zinc nitrate hexahydrate; and 75-80 parts of an organic cosolvent. According to the invention, the ratio of the raw materials, especially the ratio of 2-methylimidazole to zinc nitrate hexahydrate, is optimized, so that the formation conditions of ZIF-8 are optimized, and the thermal stability of ZIF-8 is improved. The structural integrity of the material can be maintained under high temperature and harsh conditions, and the material is suitable for application occasions requiring high-temperature treatment. Besides, the polarity and dissolving capacity of the solvent can be effectively improved through selection of the organic cosolvent, crystal growth of ZIF-8 is promoted, then the crystal morphology and performance of ZIF-8 are affected, and the final product has better physical and chemical properties.

The invention discloses a lithium hexafluorophosphate production control system and a method thereof, and relates to the technical field of lithium hexafluorophosphate production, and the method specifically comprises the following steps: obtaining crystallization dynamic information of each area in a reaction kettle in a lithium hexafluorophosphate crystallization process in real time, and analyzing after obtaining to obtain a crystallization dynamic result; respectively generating a crystal growth driving force coefficient and a particle uniform distribution index of each region; constructing a particle size distribution evaluation model for the generated crystal growth driving force coefficient and particle uniform distribution index of each region, generating a particle size distribution coefficient of each region, and performing comprehensive analysis after generation to generate an evaluation coefficient; and analyzing the generated evaluation coefficient, and evaluating the uniformity degree of particle size distribution in the reaction kettle in the lithium hexafluorophosphate crystallization process. The problem of uneven particle size distribution in the lithium hexafluorophosphate crystallization process is solved, and the effect of improving the particle size uniformity and the product quality stability is achieved.

The invention relates to a compound selenium-indium-cesium and a selenium-indium-cesium infrared nonlinear optical crystal as well as a preparation method and application thereof. The molecular formula of the compound is CsIn5Se8, the molecular weight is 1338.69, the molecular formula of the crystal is CsIn5Se8, the molecular weight is 1338.69, the structure has an asymmetric center and belongs to a triclinic system, the space group is P1, and the cell parameters are as follows: a is 9.1506 (3), b is 9.1793 (3), c is 11.2778 (3), alpha is 89.9560 (10) degrees, beta is 72.0140 (10) degrees, gamma is 72.0340 (10) degrees, Z is 2, and the volume is 852.38 (5) 3. The crystal is prepared by adopting a high-temperature melt method, a chemical vapor transport method, a Bridgman-Stockbarger method or a fluxing agent method. The obtained selenium-indium-cesium infrared nonlinear optical crystal has the advantages of large nonlinear optical response, good crystal growth habit, good mechanical property, difficulty in fragmentation and deliquescence, easiness in processing and storage and the like, and can be used for manufacturing infrared nonlinear optical devices; the method has important application in the fields of photoelectric countermeasure, spectrum technology, laser communication, remote sensing distance measurement and the like.

An object of the present invention is to provide a novel technique capable of manufacturing a large-diameter AlN substrate.The present invention is a method for manufacturing an AlN substrate, including a crystal growth step S30 of forming an AlN layer 20 on a SiC underlying substrate 10 having through holes 11. In addition, the present invention is a method for forming an AlN layer including the through hole formation step S20 of forming the through holes 11 in the SiC underlying substrate 10 before forming the AlN layer 20 on the SiC underlying substrate 10.

The invention relates to an indium phosphide crystal containing doped elements, a single crystal wafer and a preparation method of the indium phosphide crystal. Specifically, the invention relates to an indium phosphide crystal containing a doped element, the doped element is doped in an indium phosphide crystal growth melt or in indium phosphide polycrystalline material synthesis, and the indium phosphide crystal is an S-doped or Sn-doped N-type indium phosphide single crystal or a Zn-doped P-type indium phosphide single crystal. The doped element is one or more elements, and the segregation coefficient of the doped element in indium phosphide is not greater than 0.05; and the content of the doped element in the indium phosphide crystal is 30 ppb to 30 ppm. The invention also relates to a method for preparing the indium phosphide crystal containing the doped elements, a method for preparing a single crystal wafer and a device prepared from the indium phosphide single crystal. The indium phosphide crystal containing the doped elements obtained according to the invention is high in single crystal yield.

The invention provides a preparation method of magnesium niobate, which comprises the following steps: carrying out wet ball milling on MgO and Nb2O5, uniformly mixing, and drying to obtain mixed powder; the mixed powder is heated to 1500-1700 DEG C for 1-3 h and then subjected to water quenching, and solid particles of a core-shell structure inclusion are obtained; and heating the solid particles to 1000-1200 DEG C, and carrying out heat preservation to obtain the magnesium niobate. Solid particles of a core-shell structure inclusion are formed through a water quenching process, then MN obtained through rapid heating sintering is high in purity and stability, Mg < 2 + > and Nb < 5 + > in the MN are high in uniformity and large in reaction activity, sufficient mixing with PbO and TiO2 at a high temperature is facilitated to form a liquid phase, the formed raw material for PMNT crystal growth is better in singleness and uniformity, and the preparation method is simple and easy to implement. Furthermore, the PMNT single crystal with a single perovskite structure, high purity and excellent piezoelectric property can be obtained, and the yield is improved.

The invention provides a combined crucible and an oxide crystal growth method.The combined crucible is used for oxide crystal growth and comprises a first ceramic crucible, a second ceramic crucible, a third ceramic crucible and a fourth ceramic crucible, the graphite layer is arranged in the first ceramic crucible; the second ceramic crucible comprises a second containing space with the top open and the bottom closed, and the second ceramic crucible is arranged in the graphite layer. The combined crucible is designed by adopting an iridium-free scheme, so that the cost of the crucible can be greatly reduced.

This application provides a crystal growth method and crystalline silicon, relating to the field of solar photovoltaic technology. The method comprises: performing a leak test on a single crystal furnace under a first furnace pressure; adding a dopant to the single crystal furnace under a second furnace pressure; wherein the second furnace pressure is greater than the first furnace pressure; and performing a crystal pulling process after adding the dopant. This application can reduce axial concentration distribution differences of doping elements in doped single crystal silicon, improve axial resistivity uniformity of the single crystal silicon, and enhance production efficiency.

The invention belongs to the technical field of photovoltaic solar materials, and particularly relates to a high-conversion-efficiency perovskite precursor material and a preparation method thereof. The high-conversion-efficiency perovskite precursor material is composed of phenyl ammonium cesium composite cations, metal halide, an additive, a nuclear auxiliary agent and a solvent. By compounding phenylethyl ammonium iodide and cesium iodide, phenylammonium and cesium cations are introduced into perovskite crystal lattices, organic-inorganic balance of the material is optimized, phenylammonium promotes formation of a quasi-two-dimensional structure, and damp-heat stability is enhanced; cesium ions fill A-site gaps, so that crystal lattices are tighter, and the thermal stability and the photoelectric conversion efficiency are improved; the synergistic matching addition of the metal halide realizes band gap regulation and control and spectrum matching, and quaternary ammonium salt adjusts nucleation and grain growth, so that a uniform film structure is ensured, and defects are reduced; and guanidine salt passivates defects after crystal growth, stabilizes crystal lattices, and improves charge life and device efficiency.

The invention provides a crystal growth device and a crystal growth method for separating crystals from melts, and solves the defect that polycrystals are easy to generate during crystal growth at present. The growth device comprises a heat preservation furnace, a heater, a crystal growth crucible, a lining crucible, a lifting mechanism, a ceramic lifting seat, pressing graphite, a heat conduction graphite ring and a heat preservation ring, the crystal growth crucible is coaxially arranged in the heat preservation furnace; the heater is coaxially arranged between the crystal growth crucible and the holding furnace; the lining crucible is coaxially arranged in the crystal growth crucible and comprises a crucible bottom plate, a melt transmission channel and a crucible main body which are coaxial and communicated from bottom to top; in order to reduce the influence of the melt on the crystal in the growth process, the crystal and the melt are physically separated, the growth device with the two crucibles is designed, and in consideration of the importance of stable crystal growth thermal field environment, heat transfer of the two crucibles is isolated through the heat preservation ring; the heat-conducting graphite is used for uniformizing the temperature of the center and the edge of the melt, and concave liquid surfaces are avoided.

The utility model discloses a thermal field structure for X-cut lithium niobate crystal growth, the X-axis is defined to extend upwards, the thermal field structure comprises a thermal insulation structure and a crucible, both the thermal insulation structure and the crucible are elliptical cylinders with open upper ends and closed lower ends, when the thermal field structure is used, the crucible is placed in the thermal insulation structure, the central axes of the crucible and the thermal insulation structure coincide, and the central axes of the crucible and the thermal insulation structure coincide. The heat preservation structure is provided with a long axis a1 and a short axis b1, the crucible is provided with a long axis a2 and a short axis b2, the long axis of the heat preservation structure and the long axis of the crucible both extend in the Y-axis direction, the short axis of the heat preservation structure and the short axis of the crucible both extend in the Z-axis direction, and the grown lithium niobate crystal is an elliptic cylinder. According to the utility model, the problem that the crystal is easy to crack in the prior art is solved, and the success rate of the growth of the X-axis lithium niobate crystal is improved.

The invention discloses a preparation method of high-sphericity titanium-based corrosion-resistant high-entropy alloy powder, and relates to the technical field of metal powder preparation, and the preparation method is technically characterized by comprising the following steps that S1, titanium-based high-entropy alloy raw materials are smelted into melt in a vacuum induction smelting furnace, and the titanium-based high-entropy alloy raw materials comprise, by atomic percent, 30%-40% of Ti, 5%-15% of Al, 3%-10% of Cr, 2%-8% of Nb and 1% of Mo; the method has the technical effects that dendritic crystal growth is inhibited and heavy element segregation is eliminated through the synergistic effect of low-frequency and high-frequency magnetic fields, so that the powder composition segregation index of the embodiment is superior to that of a contrast, the element distribution uniformity is improved by multiple times, and the hollow powder rate is remarkably reduced compared with that of a magnetic-field-free process.

The present invention relates to the field of the preparation of silicon carbide crystals, and in particular to a device and method for the diameter expansion growth of a silicon carbide crystal. The device comprises a graphite diameter expansion device comprising a porous graphite diameter expansion ring. The porous graphite diameter expansion ring serves as a gas channel and is used for releasing an accumulated growth atmosphere during the diameter expansion growth of the silicon carbide crystal. The porous graphite diameter expansion ring not only ensures the smoothness of gas exhaust, but also solves the problem of polycrystalline silicon carbide growing on an edge of a silicon carbide seed crystal hindering the diameter expansion of the silicon carbide crystal. In addition, in the axial direction of the graphite diameter expansion device and in a direction away from the silicon carbide seed crystal, the porosity of the porous graphite diameter expansion ring gradually decreases, so that the growth atmosphere in a graphite crucible is controlled to ensure that the growth atmosphere can be discharged in time when the growth atmosphere is excessive in the early stage, and the discharge amount is reduced when the growth atmosphere in the later growth stage is insufficient, thus increasing the growth rate of the silicon carbide crystal. In addition, hard graphite felt is arranged around the diameter expansion device to serve as a heat insulation material, so that a rational temperature gradient of silicon carbide crystal growth is maintained.

The invention discloses a preparation method for effectively reducing defects of a perovskite solar cell body. A 4-fluorobenzenesulfonamide additive is introduced into a perovskite precursor solution, a sulfonyl group, a fluorine group and the like are coordinated with lead in perovskite, the crystallization process of the film is regulated and controlled, nucleation and crystal growth of an organic lead halide perovskite light absorption layer are effectively controlled, meanwhile, non-radiative recombination is inhibited, charge transfer is promoted, and the photoelectric conversion efficiency is improved. The photoelectric conversion efficiency is obviously improved, the cost is reduced and the repeatability is good. The additive is introduced by a solution method, the process is simple and the cost is low. Experimental results show that after the 4-fluorobenzenesulfonamide additive is used, the trap state density of a perovskite layer is reduced from 4.45 * 10 < 15 > cm <-3 > to 3.26 * 10 < 15 > cm <-3 >, and the photoelectric conversion efficiency of a perovskite cell is improved from 22.20% to 24.15%. The invention provides an efficient and low-cost solution for defect passivation of the perovskite solar cell.