High-quality black phosphorus crystal continuous preparation system and method for preparing black phosphorus crystal by using same

Abstract

The invention discloses a high-quality black phosphorus crystal continuous preparation system which comprises a raw material preheating and activating mechanism, an intermediate in-situ generation mechanism and a crystal growth mechanism, and a metal source raw material supply mechanism outlet of the raw material preheating and activating mechanism is connected with the top of the intermediate in-situ generation mechanism through a pipeline; an outlet of the phosphorus source raw material supply mechanism is respectively connected with the bottom of the intermediate in-situ generation mechanism and the crystal growth mechanism through two pipelines, an outlet of the iodine source raw material supply mechanism is respectively connected with two sides of the intermediate in-situ generation mechanism through two pipelines, and a static magnetic field generation mechanism is arranged on the outer side of the intermediate in-situ generation mechanism. An outlet of the intermediate in-situ generation mechanism is connected with the top of the crystal growth mechanism; a crystal growth region in the crystal growth mechanism is positioned at the bottom of the crystal growth mechanism. The invention solves the problems of low black phosphorus crystal production efficiency, low raw material utilization rate and inconvenience in continuous production in industrial production in the traditional CVT method.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of two-dimensional material preparation, in particular to a high-quality black phosphorus crystal continuous preparation system and a method for preparing black phosphorus crystals by using the same. BACKGROUND

[0002] Black phosphorus, as a two-dimensional layered material with a direct band gap, high carrier mobility and significant anisotropy, has shown great application potential in the fields of transistors, photodetectors, batteries, catalysis and biomedicine. Chemical vapor transport (CVT) is one of the mainstream methods for preparing bulk black phosphorus single crystals, and the Sn / I2 / P system is widely studied due to its relatively low cost and good effect.

[0003] However, the existing CVT method for preparing black phosphorus still faces many technical barriers, especially when trying to scale up production. (1) The nucleation and growth mechanism is not clear, and the controllability is poor. Some research reports indicate that Sn 24 P 22–x I8 and other ternary cage compounds are essential as nucleating agents in the Sn / I2 / P system, but the precise nucleation and growth mechanism, especially the gradual transformation path from red phosphorus to black phosphorus, is not fully understood. This leads to the determination of process parameters (such as reaction temperature, material concentration ratio, and reaction chamber pressure) largely relying on experience, making it difficult to accurately control the size, morphology and layer number of the crystal, and the repeatability is poor.

[0004] (2) Low reaction efficiency and low raw material utilization rate: traditional CVT method usually seals the reactants in a vacuum quartz tube for batch reaction. This method has problems such as insufficient contact between reactants, low mass and heat transfer efficiency, leading to long reaction period, and often incomplete conversion of residual red phosphorus and the generation of Sn x P y and other by-products, which need to be improved in terms of raw material conversion rate and yield.

[0005] (3) Difficult to achieve continuous and large-scale production: the traditional sealed tube method is essentially a batch operation, which is not conducive to continuous production in industry. Although CN117566702B proposes a device with a feeding and recycling system, there are still some problems, such as the core reaction area may still face the problem of uneven mixing of multiphase flow and incomplete conversion of intermediates, affecting the consistency of crystal quality and the scalability of production; the recycling of raw materials is complex, and the ratio of each substance in the recycled material changes, which is no longer suitable for recycling, and is easy to affect the subsequent reaction.

[0006] Therefore, breaking through the existing technical barriers and developing a black phosphorus preparation method based on a deep understanding of the growth mechanism, which can achieve efficient, controllable, safe and easy to scale, is the key to promoting black phosphorus to practical applications. SUMMARY

[0007] The application aims to provide a high-quality black phosphorus crystal continuous preparation system and a method for preparing black phosphorus crystals by using the same, and solve the problems of low production efficiency, poor raw material utilization, and inconvenience in continuous production in industrial production of black phosphorus crystals produced by using the traditional CVT method.

[0008] To solve the above technical problems, the application adopts the following technical solutions: A high-quality black phosphorus crystal continuous preparation system comprises a raw material preheating and activation mechanism, an intermediate in-situ generation mechanism, and a crystal growth mechanism. A preheating and activation bin of the raw material preheating and activation mechanism is provided with a metal raw material preheating cavity, a phosphorus raw material preheating cavity, and an iodine raw material preheating cavity. A raw material bin is provided outside the preheating and activation bin. The metal raw material preheating cavity, the phosphorus raw material preheating cavity, and the iodine raw material preheating cavity are respectively connected with a metal source supply bin, a phosphorus source supply bin, and an iodine source supply bin in the raw material bin through pipelines. An outlet of the metal raw material preheating cavity is connected with the top of the intermediate in-situ generation mechanism through a pipeline. A nozzle for atomizing a liquid metal source is arranged at a metal raw material interface at the top of the intermediate in-situ generation mechanism. An outlet of the phosphorus raw material preheating cavity is connected with the bottom of the intermediate in-situ generation mechanism and the crystal growth mechanism through two pipelines respectively. An outlet of the iodine raw material preheating cavity is connected with two sides of the intermediate in-situ generation mechanism through two pipelines respectively. A static magnetic field generating mechanism is arranged outside the intermediate in-situ generation mechanism. An outlet of the intermediate in-situ generation mechanism is connected with the top of the crystal growth mechanism. A crystal growth zone in the crystal growth mechanism is located at the bottom of the crystal growth mechanism.

[0009] In the raw material preheating and activation mechanism, the phosphorus raw material, the iodine raw material, and the metal raw material are preheated and activated. The preheated and activated raw materials are sent to the intermediate in-situ generation mechanism. The gaseous P4 and the gaseous I2 are sent to the intermediate in-situ generation mechanism through a pressure gradient. The liquid metal source is injected into the intermediate in-situ generation mechanism in the form of nozzle atomization through a carrier gas. The gaseous P4, the gaseous I2, and the liquid metal source are injected simultaneously. The flow rate is used to ensure that the reactants fully contact at the gas-liquid interface. The intermediate in-situ generation system is vacuumized before the injection of the reactants. The reactants are kept for 2-8 hours after being injected, so as to ensure that the nucleating agent precursor with high activity is generated in-situ. The nucleating agent precursor is determined by the type of the metal source, including but not limited to Sn 24 P 22-a I8、Pb x P y I z 、Bi x P y I zOne or more of the following are used: a is 1-4, x is 2-5, y is 0.1-3, and z is 1-10. Under the influence of a pressure gradient, the generated aerosol or gaseous product containing nucleating agent precursors is injected into the crystal growth mechanism. The crystal growth mechanism is under vacuum before the nucleating agent precursors are injected, and black phosphorus seed crystals are pre-placed inside it. After the nucleating agent precursors are injected, the pressure of the crystal growth system is maintained at 0.5MPa-8.0MPa to induce heteroepitaxial nucleation and preferential growth of black phosphorus. After crystal growth occurs, when the pressure drops, the phosphorus source is replenished in time through the pipeline connected to the phosphorus source supply mechanism.

[0010] A breakthrough has been achieved in controlling nucleation: by spatially and temporally separating and regulating the generation of nucleating agents from the growth of black phosphorus (i.e., "synthesizing nucleating agents first, then growing crystals"), active intervention in the nucleation process of black phosphorus has been realized. This overcomes the problem of random and uncontrollable nucleation in the traditional CVT method, and is beneficial for obtaining black phosphorus crystals with uniform size and higher crystal quality.

[0011] Improved reaction efficiency and raw material utilization: The use of gas-phase directional transport and in-situ generation of highly reactive intermediates significantly improved mass transfer and mixing efficiency between reactants, promoting complete reaction. Combined with a material recycling system, this significantly increased raw material conversion and utilization rates, reducing production costs.

[0012] Compared to the traditional batch processing and sealing method, it is easier to scale up and integrate equipment, providing a feasible technical path for the continuous and large-scale preparation of black phosphorus. Specifically, the crystal growth mechanism is connected to the phosphorus raw material preheating chamber, which can be used to replenish the vacancies left after the nucleating agent precursor is generated into black phosphorus, thus ensuring the continuous preparation of black phosphorus.

[0013] As a further preferred embodiment of the present invention, valves are provided in the middle of each of the pipes.

[0014] It facilitates control over the speed and quantity of material conveying.

[0015] As a further preferred embodiment of the present invention, the magnetic induction intensity generated by the static magnetic field generating mechanism is 0.1-0.8T.

[0016] With a magnetic induction intensity of 0.1-0.8T, it can promote the reduction of interfacial energy by diamagnetic metal sources and rapidly form aerosols or gaseous products of nucleating agent precursors.

[0017] As a further preferred embodiment of the present invention, the raw material preheating and activation mechanism, the intermediate in-situ generation mechanism, and the crystal growth mechanism are all equipped with heating devices, vacuum control devices, and pressure monitoring and safety pressure relief devices. During the reaction process, the temperature fluctuations of the raw material preheating and activation mechanism, the intermediate in-situ generation mechanism, and the crystal growth mechanism are all controlled within ±5℃, and the vacuum degree is controlled at 10℃.-2 ~10 -1 Pa.

[0018] The small temperature fluctuations ensure a stable reaction, and the pressure monitoring and safety relief device, along with the external emergency shutdown system, ensure safe operation.

[0019] Before the raw materials are filled into the preheating activation chamber, it is under vacuum. This is achieved by vacuum pumps connected to each preheating chamber within the preheating activation chamber. Once the temperature reaches the set temperature, the raw materials are slowly added into the preheating activation chamber by the metal source supply chamber, phosphorus source supply chamber, and iodine source supply chamber under pressure. The heating device controls the heating of the preheating activation chamber through the control system. The preheated raw materials are then sent to the intermediate in-situ generation mechanism, which is also heated by the heating device controlled by the control system. The intermediate in-situ generation mechanism is also under vacuum before the preheated raw materials are added, achieved by vacuum pumps connected to the intermediate in-situ generation mechanism. After the raw materials react to generate nucleating agent precursors in the intermediate in-situ generation mechanism, they are sent to the crystal growth mechanism. The pressure monitoring and safety relief device is designed to ensure the safety of the system.

[0020] As a further preferred embodiment of the present invention, the carrier gas used in the continuous preparation system of high-quality black phosphorus crystals based on directional transport is an inert gas, and the crystal growth mechanism is connected to an inert protective gas source.

[0021] Argon or nitrogen are preferred inert gases. The inert protective gas source connected to the crystal growth mechanism is used to remove the aerosol or gaseous products of the remaining nucleating agent precursor after crystal growth is completed.

[0022] A method for preparing black phosphorus crystals using any of the above-mentioned continuous preparation systems for high-quality black phosphorus crystals based on directional transport includes the following steps: S1, under a protective atmosphere, red phosphorus raw material, metal raw material, and iodine raw material are placed in separate preheating zones for precise preheating and activation; S2, the gaseous red phosphorus, gaseous iodine, and liquid metal source obtained in step S1 are directionally transported together to an intermediate in-situ generation mechanism through a pressure gradient to generate an aerosol or gaseous product containing a nucleating agent precursor; S3, the aerosol or gaseous product containing the nucleating agent precursor generated in step S2 is injected into a crystal growth mechanism under the influence of a pressure gradient.

[0023] The above method is essentially a continuous process, which is easier to scale up and integrate equipment compared to the traditional batch sealing method, providing a feasible technical path for the continuous and large-scale preparation of black phosphorus.

[0024] As a further preferred embodiment of the present invention, the preheating activation temperature of the red phosphorus source is 590-650℃, so that it is fully converted into gaseous P4; the preheating activation temperature of the iodine source is 45-80℃, so that it is converted into gaseous I2; the metal source is one or a mixture of Sn, Pb, and Bi, wherein the preheating activation temperature of Sn is 235-300℃, the preheating activation temperature of Pb is 330-390℃, the preheating activation temperature of Bi is 275-340℃, and the metal source is melted into a liquid phase.

[0025] As a further preferred embodiment of the present invention, the gas phase P4 and gas phase I2 obtained in S1 are injected into the intermediate in-situ generation mechanism through a pressure gradient, while the liquid metal source is injected into the intermediate in-situ generation mechanism in the form of atomization through a nozzle using a carrier gas. The carrier gas is an inert gas. The gas phase P4, gas phase I2 and liquid metal source are injected into the intermediate in-situ generation mechanism simultaneously, and the flow rate is used to ensure that the reactants are in full contact at the gas-liquid interface.

[0026] By employing gas-phase directional transport and in-situ generation of highly reactive intermediates, the mass transfer and mixing efficiency between reactants is significantly improved, promoting complete reaction. Combined with a material recycling system, this significantly increases the conversion and utilization rates of raw materials and reduces production costs.

[0027] As a further preferred embodiment of the present invention, the molar ratio of red phosphorus, metal source and iodine in the in-situ intermediate generation mechanism is 100:(5-20):(3-10), the temperature of the in-situ intermediate generation mechanism is maintained at 500-650℃, the magnetic induction intensity of the static magnetic field of the in-situ intermediate generation mechanism is 0.1-0.8T, the in-situ intermediate generation mechanism is a vacuum before the reactants are injected, and the temperature is maintained for 2-8 hours after the reactants are injected. In the in-situ intermediate generation mechanism, the reaction temperatures of the Sn source, Pb source and Bi source are 580-600℃, 590-610℃ and 610-630℃, respectively, and the pressure of the intermediate reaction mechanism is maintained at 1-10 MPa.

[0028] The magnetic induction intensity of the static magnetic field is preferably 0.3-0.4T. The intermediate in-situ generation mechanism is under vacuum before the reactants are injected and kept at a temperature for 2-8 hours after the reactants are injected, which can ensure the in-situ generation of highly active nucleating agent precursors. The pressure of the intermediate reaction mechanism is preferably 2-4 MPa.

[0029] As a further preferred embodiment of the present invention, the temperature of the crystal production mechanism is maintained at 550-620℃, and the crystal growth mechanism is under vacuum before the S2 nucleating agent precursor is injected; after the S2 nucleating agent precursor is injected, the pressure of the crystal growth mechanism is maintained at 0.5MPa-8.0MPa, black phosphorus seed crystals are pre-placed in the crystal growth mechanism, and when the pressure drops after crystal growth occurs, phosphorus source is replenished in time; the temperature of the crystal growth zone in the crystal growth mechanism is cooled in stages: first, it is kept at 570-590℃ for 1-10 hours, then it is cooled at a uniform rate of 1-5℃ / min to 480-520℃ and kept at that temperature for 2-4 hours; then, it is naturally cooled to room temperature, inert gas is injected, and the remaining aerosol or gaseous products of the nucleating agent precursor are removed before the product is collected.

[0030] The pressure of the crystal growth mechanism is preferably 1.0 MPa-3.0 MPa.

[0031] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: 1. By refining and actively controlling the CVT process, especially optimizing the formation and transport process of nucleating agent precursors, high-quality, high-efficiency and controllable preparation of black phosphorus crystals can be achieved.

[0032] 2. By separating and controlling the generation of nucleating agents and the growth of black phosphorus to a certain extent in space and time (i.e., "synthesizing nucleating agents first, then growing crystals"), active intervention in the nucleation process of black phosphorus is achieved. This overcomes the problem of random and uncontrollable nucleation in the traditional CVT method and is conducive to obtaining black phosphorus crystals with uniform size and higher crystal quality.

[0033] 3. Improved reaction efficiency and raw material utilization: The use of gas-phase directional transport and in-situ generation of highly reactive intermediates greatly improves the mass transfer and mixing efficiency between reactants, promoting complete reaction. Combined with a material recycling system, this significantly increases the conversion and utilization rate of raw materials and reduces production costs. Attached Figure Description

[0034] Figure 1 This is a diagram of the preparation system for black phosphorus crystals according to the present invention.

[0035] Figure 2 This is a schematic diagram of the raw material preheating and activation mechanism in this invention.

[0036] Figure 3 This is a schematic diagram of the structure of the intermediate in-situ generation mechanism of the present invention.

[0037] Figure 4 This is a schematic diagram of the crystal growth mechanism of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0043] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Specific Implementation

[0044] Figure 1 , Figure 2 ,Figure 3 , Figure 4 A continuous preparation system for high-quality black phosphorus crystals is shown, comprising a raw material preheating and activation mechanism 1, an intermediate in-situ generation mechanism 2, and a crystal growth mechanism 3. The preheating and activation mechanism 1 has a preheating and activation chamber containing a metal raw material preheating chamber 11, a phosphorus raw material preheating chamber 12, and an iodine raw material preheating chamber 13. A raw material chamber 4 is located outside the preheating and activation chamber. The metal raw material preheating chamber 11, phosphorus raw material preheating chamber 12, and iodine raw material preheating chamber 13 are respectively connected to the metal source supply chamber, phosphorus source supply chamber, and iodine source supply chamber within the raw material chamber 4 via pipelines. The outlet of the metal raw material preheating chamber 11 is connected to the intermediate in-situ generation mechanism via a pipeline. The top of the intermediate in-situ generation mechanism 2 is connected to the top of the intermediate in-situ generation mechanism 1. The metal raw material interface at the top of the intermediate in-situ generation mechanism 2 is equipped with a nozzle for atomizing the liquid metal source. The outlet of the phosphorus raw material preheating chamber 12 is connected to the bottom of the intermediate in-situ generation mechanism 1 and the crystal growth mechanism 3 through two pipes respectively. The outlet of the iodine raw material preheating chamber 13 is connected to both sides of the intermediate in-situ generation mechanism 1 through two pipes respectively. The outside of the intermediate in-situ generation mechanism 1 is equipped with a static magnetic field generating mechanism 5. The outlet of the intermediate in-situ generation mechanism 2 is connected to the top of the crystal growth mechanism 3. The crystal growth area in the crystal growth mechanism 3 is located at its bottom.

[0045] In the raw material preheating and activation unit, phosphorus, iodine, and metal raw materials are preheated and activated. The preheated and activated raw materials are then sent to the intermediate in-situ generation unit. Specifically, gaseous P4 and gaseous I2 are fed to the intermediate in-situ generation unit via a pressure gradient, while the liquid metal source is injected into the intermediate in-situ generation unit via a nozzle atomization using a carrier gas. Gaseous P4, gaseous I2, and liquid metal sources are injected simultaneously, and the flow rate ensures sufficient contact between the reactants at the gas-liquid interface. The intermediate in-situ generation system is under vacuum before reactant injection, and is kept at a constant temperature for 2-8 hours after injection to ensure the in-situ generation of a highly active nucleating agent precursor. The nucleating agent precursor is determined by the type of metal source, including but not limited to Sn. 24 P 22-a I8, Pb x P y I z Bi x P y I zOne or more of the following are used: a is 1-4, x is 2-5, y is 0.1-3, and z is 1-10. Under the influence of a pressure gradient, the generated aerosol or gaseous product containing nucleating agent precursors is injected into the crystal growth mechanism. The crystal growth mechanism is under vacuum before the nucleating agent precursors are injected, and black phosphorus seed crystals are pre-placed inside it. After the nucleating agent precursors are injected, the pressure of the crystal growth system is maintained at 0.5MPa-8.0MPa to induce heteroepitaxial nucleation and preferential growth of black phosphorus. After crystal growth occurs, when the pressure drops, the phosphorus source is replenished in time through the pipeline connected to the phosphorus source supply mechanism.

[0046] A breakthrough has been achieved in controlling nucleation: by spatially and temporally separating and regulating the generation of nucleating agents from the growth of black phosphorus (i.e., "synthesizing nucleating agents first, then growing crystals"), active intervention in the nucleation process of black phosphorus has been realized. This overcomes the problem of random and uncontrollable nucleation in the traditional CVT method, and is beneficial for obtaining black phosphorus crystals with uniform size and higher crystal quality.

[0047] Improved reaction efficiency and raw material utilization: The use of gas-phase directional transport and in-situ generation of highly reactive intermediates significantly improved mass transfer and mixing efficiency between reactants, promoting complete reaction. Combined with a material recycling system, this significantly increased raw material conversion and utilization rates, reducing production costs.

[0048] Compared to the traditional batch processing and sealing method, it is easier to scale up and integrate equipment, providing a feasible technical path for the continuous and large-scale preparation of black phosphorus. Specifically, the crystal growth mechanism is connected to the phosphorus raw material preheating chamber, which can be used to replenish the vacancies left after the nucleating agent precursor is generated into black phosphorus, thus ensuring the continuous preparation of black phosphorus. Specific Implementation Example 1

[0050] This embodiment further illustrates the pipeline based on specific embodiment 1, wherein valves are installed in the middle of the pipeline.

[0051] It facilitates control over the speed and quantity of material conveying. Specific Implementation Example 2

[0053] This embodiment further describes the static magnetic field generating mechanism based on specific embodiment 1. The magnetic induction intensity generated by the static magnetic field generating mechanism 5 is 0.1-0.8T.

[0054] With a magnetic induction intensity of 0.1-0.8T, it can promote the reduction of interfacial energy by diamagnetic metal sources and rapidly form aerosols or gaseous products of nucleating agent precursors. Specific Implementation Example 3

[0056] This embodiment further describes the raw material preheating and activation mechanism, the intermediate in-situ generation mechanism, and the crystal growth mechanism based on specific embodiment 1. The raw material preheating and activation mechanism 1, the intermediate in-situ generation mechanism 2, and the crystal growth mechanism 3 are all equipped with a heating device 6, a vacuum control device 7, and a pressure monitoring and safety pressure relief device. During the reaction process, the temperature fluctuations of the raw material preheating and activation mechanism 1, the intermediate in-situ generation mechanism 2, and the crystal growth mechanism 3 are controlled within ±5℃, and the vacuum degree is controlled at 10℃. -2 ~10 -1 Pa.

[0057] The small temperature fluctuations ensure a stable reaction, and the pressure monitoring and safety relief device, along with the external emergency shutdown system, ensure safe operation. Specific Implementation Example 4

[0059] This embodiment further explains the carrier gas used in the continuous preparation system of high-quality black phosphorus crystals based on directional transport, based on specific embodiment 1. The carrier gas used in the continuous preparation system of high-quality black phosphorus crystals based on directional transport is an inert gas, and the crystal growth mechanism is connected to an inert protective gas source.

[0060] Argon or nitrogen are preferred inert gases. The inert protective gas source connected to the crystal growth mechanism is used to remove the aerosol or gaseous products of the remaining nucleating agent precursor after crystal growth is completed. Specific Implementation Example 5

[0062] A method for preparing black phosphorus crystals using any of the above-mentioned continuous preparation systems for high-quality black phosphorus crystals based on directional transport includes the following steps: S1, under a protective atmosphere, red phosphorus raw material, metal raw material, and iodine raw material are placed in separate preheating zones for precise preheating and activation; S2, the gaseous red phosphorus, gaseous iodine, and liquid metal source obtained in step S1 are directionally transported together to the intermediate in-situ generation mechanism 2 through a pressure gradient to generate an aerosol or gaseous product containing a nucleating agent precursor; S3, the aerosol or gaseous product containing the nucleating agent precursor generated in step S2 is injected into the crystal growth mechanism 3 under the influence of a pressure gradient. The red phosphorus source is preheated and activated at 590°C to fully convert it into gaseous P4; the iodine source is preheated and activated at 45°C to convert it into gaseous I2; the metal source is one or a mixture of Sn, Pb, and Bi, wherein the preheating and activation temperature of Sn is 260°C, the preheating and activation temperature of Pb is 330°C, and the preheating and activation temperature of Bi is 340°C, and the metal source is molten into a liquid phase. The gas phase P4 and gas phase I2 obtained in S1 are injected into the intermediate in-situ generation mechanism 2 through a pressure gradient, while the liquid metal source is injected into the intermediate in-situ generation mechanism 2 in the form of atomization through a nozzle using a carrier gas. The carrier gas is an inert gas. The gas phase P4, gas phase I2 and liquid metal source are injected into the intermediate in-situ generation mechanism 2 at the same time, and the flow rate is used to ensure that the reactants are in full contact at the gas-liquid interface. The molar ratio of red phosphorus, metal source, and iodine in the intermediate in-situ generation mechanism 2 is 100:5:7. The temperature of the intermediate in-situ generation mechanism 2 is maintained at 650°C. The magnetic induction intensity of the static magnetic field in the intermediate in-situ generation mechanism 2 is 0.8T. The intermediate in-situ generation mechanism 2 is under vacuum before the reactants are injected. After the reactants are injected, the temperature is maintained for 2 hours. In the intermediate in-situ generation mechanism 2, the reaction temperatures of the Sn source, Pb source, and Bi source are 580°C, 610°C, and 620°C, respectively. The pressure of the intermediate reaction mechanism 2 is maintained at 1 MPa. The temperature of the crystal production mechanism is maintained at 620℃. The crystal growth mechanism 3 is under vacuum before the S2 nucleating agent precursor is injected. After the S2 nucleating agent precursor is injected, the pressure of the crystal growth mechanism 3 is maintained at 8.0MPa. Black phosphorus seed crystals are pre-placed in the crystal growth mechanism 3. After crystal growth occurs, when the pressure drops, phosphorus source is replenished in time. The temperature of the crystal growth zone in the crystal growth mechanism 3 is reduced in stages. First, it is kept at 570℃ for 1 hour. Then, it is cooled to 480℃ at a uniform rate of 2℃ / min and kept at that temperature for 3 hours. Then, it is naturally cooled to room temperature. Inert gas is injected to remove the remaining aerosol or gaseous products of the nucleating agent precursor before the product is collected. Specific Implementation Example 6

[0064] A method for preparing black phosphorus crystals using any of the above-mentioned continuous preparation systems for high-quality black phosphorus crystals based on directional transport includes the following steps: S1, under a protective atmosphere, placing a red phosphorus source, a metal source, and an iodine source in separate preheating zones for precise preheating and activation; S2, the gaseous red phosphorus, gaseous iodine, and liquid metal source obtained in step S1 are directionally transported together through a pressure gradient to an intermediate in-situ generation mechanism to generate an aerosol or gaseous product containing a nucleating agent precursor; S3, the aerosol or gaseous product containing the nucleating agent precursor generated in step S2 is injected into a crystal growth mechanism under the influence of a pressure gradient. The preheating activation temperature of the red phosphorus source is 620°C, which allows it to be fully converted into gaseous P4; the preheating activation temperature of the iodine source is 80°C, which allows it to be converted into gaseous I2; the metal source is one or a mixture of Sn, Pb, and Bi, wherein the preheating activation temperature of Sn is 300°C, the preheating activation temperature of Pb is 390°C, and the preheating activation temperature of Bi is 320°C, and the metal source is melted into a liquid phase. The gaseous P4 and gaseous I2 obtained in S1 are injected into the intermediate in-situ generation mechanism through a pressure gradient, while the liquid metal source is injected into the intermediate in-situ generation mechanism in the form of atomization through a nozzle using a carrier gas. The carrier gas is an inert gas. The gaseous P4, gaseous I2 and liquid metal source are injected into the intermediate in-situ generation mechanism at the same time, and the flow rate is used to ensure that the reactants are in full contact at the gas-liquid interface. The molar ratio of red phosphorus, metal source, and iodine in the in-situ intermediate generation mechanism is 100:20:3. The temperature of the in-situ intermediate generation mechanism is maintained at 500℃. The magnetic induction intensity of the static magnetic field in the in-situ intermediate generation mechanism is 0.1T. The in-situ intermediate generation mechanism is under vacuum before the reactants are injected. After the reactants are injected, the mechanism is kept at a constant temperature for 8 hours. In the in-situ intermediate generation mechanism, the reaction temperatures of the Sn source, Pb source, and Bi source are 590℃, 600℃, and 610℃, respectively. The pressure of the intermediate reaction mechanism is maintained at 10 MPa. The temperature of the crystal production mechanism is maintained at 600℃. The crystal growth mechanism is under vacuum before the S2 nucleating agent precursor is injected. After the S2 nucleating agent precursor is injected, the pressure of the crystal growth mechanism is maintained at 0.5MPa. Black phosphorus seed crystals are pre-placed in the crystal growth mechanism. After crystal growth occurs, when the pressure drops, phosphorus source is replenished in time. The temperature of the crystal growth zone in the crystal growth mechanism is reduced in stages. First, it is kept at 580℃ for 5 hours. Second, it is cooled to 500℃ at a uniform rate of 1℃ / min and kept at that temperature for 4 hours. Then, it is naturally cooled to room temperature. Inert gas is injected to remove the remaining aerosol or gaseous products of the nucleating agent precursor before the product is collected. Specific Implementation Example 7

[0066] A method for preparing black phosphorus crystals using any of the above-mentioned continuous preparation systems for high-quality black phosphorus crystals based on directional transport includes the following steps: S1, under a protective atmosphere, placing a red phosphorus source, a metal source, and an iodine source in separate preheating zones for precise preheating and activation; S2, the gaseous red phosphorus, gaseous iodine, and liquid metal source obtained in step S1 are directionally transported together through a pressure gradient to an intermediate in-situ generation mechanism to generate an aerosol or gaseous product containing a nucleating agent precursor; S3, the aerosol or gaseous product containing the nucleating agent precursor generated in step S2 is injected into a crystal growth mechanism under the influence of a pressure gradient. The red phosphorus source is preheated and activated at 650°C to fully convert it into gaseous P4; the iodine source is preheated and activated at 60°C to convert it into gaseous I2; the metal source is one or a mixture of Sn, Pb, and Bi, wherein the preheating and activation temperature of Sn is 235°C, the preheating and activation temperature of Pb is 360°C, and the preheating and activation temperature of Bi is 275°C, and the metal source is melted into a liquid phase. The gaseous P4 and gaseous I2 obtained in S1 are injected into the intermediate in-situ generation mechanism through a pressure gradient, while the liquid metal source is injected into the intermediate in-situ generation mechanism in the form of atomization through a nozzle using a carrier gas. The carrier gas is an inert gas. The gaseous P4, gaseous I2 and liquid metal source are injected into the intermediate in-situ generation mechanism at the same time, and the flow rate is used to ensure that the reactants are in full contact at the gas-liquid interface. The molar ratio of red phosphorus, metal source, and iodine in the in-situ intermediate generation mechanism is 100:10:10. The temperature of the in-situ intermediate generation mechanism is maintained at 600℃. The magnetic induction intensity of the static magnetic field in the in-situ intermediate generation mechanism is 0.6T. The in-situ intermediate generation mechanism is under vacuum before the reactants are injected. After the reactants are injected, the mechanism is kept at a constant temperature for 6 hours. In the in-situ intermediate generation mechanism, the reaction temperatures of the Sn source, Pb source, and Bi source are 600℃, 590℃, and 630℃, respectively. The pressure of the intermediate reaction mechanism is maintained at 8 MPa. The temperature of the crystal production mechanism is maintained at 550℃. The crystal growth mechanism is under vacuum before the S2 nucleating agent precursor is injected. After the S2 nucleating agent precursor is injected, the pressure of the crystal growth mechanism is maintained at 6.0MPa. Black phosphorus seed crystals are pre-placed in the crystal growth mechanism. After crystal growth occurs, when the pressure drops, the phosphorus source is replenished in time. The temperature of the crystal growth zone in the crystal growth mechanism is reduced in stages. First, it is kept at 590℃ for 10 hours. Second, it is cooled to 520℃ at a uniform rate of 5℃ / min and kept at that temperature for 2 hours. Then, it is naturally cooled to room temperature. Inert gas is injected to remove the remaining aerosol or gaseous products of the nucleating agent precursor before the product is collected.

[0067] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A continuous preparation system for high-quality black phosphorus crystals, characterized in that: The system includes a raw material preheating and activation mechanism (1), an intermediate in-situ generation mechanism (2), and a crystal growth mechanism (3). The preheating and activation chamber of the raw material preheating and activation mechanism (1) is equipped with a metal raw material preheating chamber (11), a phosphorus raw material preheating chamber (12), and an iodine raw material preheating chamber (13). A raw material silo (4) is located outside the preheating and activation chamber. The metal raw material preheating chamber (11), the phosphorus raw material preheating chamber (12), and the iodine raw material preheating chamber (13) are respectively connected to the metal source supply silo, the phosphorus source supply silo, and the iodine source supply silo in the raw material silo (4) through pipes. The outlet of the metal raw material preheating chamber (11) is connected to the top of the intermediate in-situ generation mechanism (2) through a pipe. The metal raw material interface at the top of the intermediate in-situ generation mechanism (2) is provided with a nozzle for atomizing the liquid metal source. The outlet of the phosphorus raw material preheating chamber (12) is connected to the bottom of the intermediate in-situ generation mechanism (1) and the crystal growth mechanism (3) through two pipes respectively. The outlet of the iodine raw material preheating chamber (13) is connected to both sides of the intermediate in-situ generation mechanism (1) through two pipes respectively. A static magnetic field generating mechanism (5) is provided on the outside of the intermediate in-situ generation mechanism (1). The outlet of the intermediate in-situ generation mechanism (2) is connected to the top of the crystal growth mechanism (3). The crystal growth area in the crystal growth mechanism (3) is located at its bottom.

2. The high-quality black phosphorus crystal continuous preparation system according to claim 1, characterized in that: Valves are installed in the middle of each of the pipelines.

3. The high-quality black phosphorus crystal continuous preparation system according to claim 1, characterized in that: The magnetic induction intensity generated by the static magnetic field generating mechanism (5) is 0.1-0.8T.

4. The high-quality black phosphorus crystal continuous preparation system according to claim 1, characterized in that: The raw material preheating and activation mechanism (1), the intermediate in-situ generation mechanism (2), and the crystal growth mechanism (3) are all equipped with a heating device (6), a vacuum control device (7), and a pressure monitoring and safety pressure relief device. During the reaction process, the temperature fluctuations of the raw material preheating and activation mechanism (1), the intermediate in-situ generation mechanism (2), and the crystal growth mechanism (3) are all controlled within ±5℃, and the vacuum degree is controlled within 10℃. -2 ~10 -1 Pa.

5. The high-quality black phosphorus crystal continuous preparation system according to claim 1, characterized in that: The carrier gas used in the continuous preparation system of high-quality black phosphorus crystals based on directional transport is an inert gas, and the crystal growth mechanism is connected to an inert protective gas source.

6. A method for preparing black phosphorus crystals using the continuous high-quality black phosphorus crystal preparation system according to any one of claims 1-5, characterized in that: The process includes the following steps: S1. Under a protective atmosphere, red phosphorus raw material, metal raw material and iodine raw material are placed in separate preheating zones for precise preheating and activation; S2. The gaseous red phosphorus, gaseous iodine and liquid metal source obtained in step S1 are transported together to the intermediate in-situ generation mechanism (2) through a pressure gradient to generate an aerosol or gaseous product containing the nucleating agent precursor; S3. The aerosol or gaseous product containing the nucleating agent precursor generated in step S2 is injected into the crystal growth mechanism (3) under the pressure gradient.

7. The method for preparing black phosphorus crystals using the high-quality black phosphorus crystal continuous preparation system according to claim 6, characterized in that: The preheating activation temperature of the red phosphorus source is 590-650℃, which allows it to be fully converted into gaseous P4; the preheating activation temperature of the iodine source is 45-80℃, which allows it to be converted into gaseous I2; the metal source is one or a mixture of Sn, Pb, and Bi, wherein the preheating activation temperature of Sn is 235-300℃, the preheating activation temperature of Pb is 330-390℃, the preheating activation temperature of Bi is 275-340℃, and the metal source is melted into a liquid phase.

8. The method for preparing black phosphorus crystals using the high-quality black phosphorus crystal continuous preparation system according to claim 6, characterized in that: The gas phase P4 and gas phase I2 obtained in S1 are injected into the intermediate in-situ generation mechanism (2) through a pressure gradient. The liquid metal source is injected into the intermediate in-situ generation mechanism (2) in the form of atomization through a nozzle by a carrier gas. The carrier gas is an inert gas. The gas phase P4, gas phase I2 and liquid metal source are injected into the intermediate in-situ generation mechanism (2) at the same time, and the flow rate is used to ensure that the reactants are in full contact at the gas-liquid interface.

9. The method for preparing black phosphorus crystals using the high-quality black phosphorus crystal continuous preparation system according to claim 6, characterized in that: The molar ratio of red phosphorus, metal source and iodine in the intermediate in-situ generation mechanism (2) is 100:(5-20):(3-10). The temperature of the intermediate in-situ generation mechanism (2) is maintained at 500-650℃. The magnetic induction intensity of the static magnetic field of the intermediate in-situ generation mechanism (2) is 0.1-0.8T. The intermediate in-situ generation mechanism (2) is a vacuum before the reactants are injected. After the reactants are injected, the temperature is maintained for 2-8 hours. In the intermediate in-situ generation mechanism (2), the reaction temperatures of the Sn source, Pb source and Bi source are 580-600℃, 590-610℃ and 610-630℃, respectively. The pressure of the intermediate reaction mechanism (2) is maintained at 1-10 MPa.

10. The method for preparing black phosphorus crystals using the high-quality black phosphorus crystal continuous preparation system according to claim 6, characterized in that: The temperature of the crystal production mechanism (3) is maintained at 550-620℃. The crystal growth mechanism (3) is in a vacuum before the S2 nucleating agent precursor is injected. After the S2 nucleating agent precursor is injected, the pressure of the crystal growth mechanism (3) is maintained at 0.5MPa-8.0MPa. Black phosphorus seed crystals are pre-placed in the crystal growth mechanism (3). After crystal growth occurs, when the pressure is detected to be low, phosphorus source is replenished in time. The temperature of the crystal growth zone in the crystal growth mechanism (3) is cooled down in stages. First, it is kept at 570-590℃ for 1-10 hours. Second, it is cooled down at a uniform rate of 1-5℃ / min to 480-520℃ and kept up for 2-4 hours. Then, it is allowed to cool naturally to room temperature, inert gas is injected, and the remaining nucleating agent precursor aerosols or gaseous products are removed before the product is collected.

Images