WO2019061017A1

WO2019061017A1 - Method for utilizing room pressure plasma in preparing two-dimensional material

Info

Publication number: WO2019061017A1
Application number: PCT/CN2017/103411
Authority: WO
Inventors: 喻学锋; 高明; 黄逸凡; 黄浩; 刘丹妮; 王佳宏
Original assignee: 深圳先进技术研究院
Priority date: 2017-09-26
Filing date: 2017-09-26
Publication date: 2019-04-04

Abstract

A method for utilizing a room pressure plasma in preparing a two-dimensional material. The method constructs a peeling apparatus of which the anode is a material crystal on the basis of a room pressure microplasma technique for peeling a material crystal to produce a two-dimensional crystal thin film. Compared with other peeling methods, the present method has simple steps, convenient operation, short time and high efficiency, obviates the need for using complex and expensive equipment and additional chemical reagents, produces no pollution to the environment and to the material surface, and is specifically applicable in preparing a two-dimensional black phosphorus material. In addition, the method can be implemented in room temperature and room pressure conditions, has an easy to control process, and favors industrial application.

Description

Method for preparing two-dimensional material by using atmospheric pressure plasma

Technical field

The invention relates to the field of preparation of two-dimensional nano materials, in particular to a method for preparing two-dimensional materials by using atmospheric pressure plasma.

Background technique

Two-dimensional crystals are nano-thickness planar crystals stacked by several layers of monoatomic layers. In recent years, two-dimensional crystal materials have become a new direction for semiconductor materials research due to their superior electrical properties.

Black Phosphorus (BP) is a homogenous allotrope of phosphorus simple substance under normal temperature and pressure. It is a graphene-like two-dimensional layered material with natural fold structure. Black phosphorus has many unique advantages over other two-dimensional materials. It has been shown that black phosphorus is a direct bandgap semiconductor, and its band gap (0.3-2.0 eV) can be adjusted in a wide range by a number of layers to achieve light absorption from near infrared to visible light. At the same time, the black phosphorus has a carrier mobility of 10 ³ cm ² /(V·s) and a switching ratio of up to 10 ⁵ . At present, black phosphorus has been widely used in the fields of optical devices and biomedicine.

It is well known that two-dimensional material layers interact through van der Waals forces, and the interlaminar forces are relatively weak, so they can generally be obtained by mechanical peeling methods. However, the material obtained by the mechanical peeling method has low efficiency and unstable quality. It is difficult to apply widely in the industry. Mechanical stripping to prepare a small amount of black phosphorus also has a low yield, and the prepared black phosphorus surface has a binder residue. At the same time, since the two-dimensional black phosphorus is easily oxidized, the stripping method needs to be carried out in an anhydrous and oxygen-free environment.

Compared with mechanical stripping, ultrasonic liquid phase stripping has a more promising application prospect, and the method can effectively isolate oxygen and facilitate material storage. Brent et al. first reported that a black bath of N-methylpyrrolidone (NMP) solution containing black phosphorus was sonicated for 24 h, and the controlled temperature was below 30 ° C, and a small layer of two-dimensional black phosphorus was obtained (ChemCommun, 2014, 50, 13338). However, the time for ultrasonic liquid phase stripping is too long, and the requirements for temperature and equipment are high, and the preparation conditions are harsh. In particular, due to the inherent cavitation of the ultrasonic waves, large-sized black phosphorus having a large size cannot be produced.

In recent years, some new methods have also been proposed. Chinese patent CN105110305A discloses a method for assisting in the preparation of polyatomic black phosphorus by supercritical carbon dioxide. The method is carried out under the condition of supercritical carbon dioxide assisted by ultrasonic liquid phase stripping to synthesize atomic layer black phosphorus. However, it is necessary to control the pressure of the supercritical device to be 150-200 bar, and the reaction conditions are severe. Chinese Patent No. CN104779380A discloses a method for electrochemically preparing phosphoenene which utilizes a chemical electrolyte containing an additive to strip black phosphorus into a phosphonene under an electric field. However, this method inevitably uses chemical additives and limits the size of the electrodes. Chinese Patent Publication No. 201510553085.0 discloses a method for preparing a black phosphonene nanosheet, which is prepared by stripping black phosphorus crystals by liquid shear force generated by a high speed rotary cutter head. But the entire preparation process needs to be in an argon atmosphere The conditions are more complicated.

In summary, in order to further expand the application of two-dimensional crystals, especially two-dimensional black phosphorus, it is necessary to improve the preparation method of two-dimensional material crystals.

Summary of the invention

The technical problem to be solved by the present invention is to develop a method for preparing a two-dimensional nanosheet material which is simple in operation, fast and efficient, mild in condition, and requires no additional chemical additives.

In particular, the present invention relates to a method for preparing a two-dimensional material by using atmospheric pressure plasma, which can realize rapid and efficient preparation of two-dimensional materials under normal temperature and pressure conditions without using complicated and expensive equipment and additional chemical reagents. .

The method is especially suitable for preparing a two-dimensional black phosphorus material, and since the solvent used is a common solvent for protecting black phosphorus, the two-dimensional black phosphorus is stripped into the solvent during the preparation process, thereby avoiding the oxidation of air or water. Conducive to maintaining the stability of two-dimensional black phosphorus.

To achieve the above object, the present invention provides the following technical solutions:

A method for preparing a two-dimensional material by using atmospheric pressure plasma, characterized in that a stripping device in which a cathode is a material crystal is constructed, and the crystal is stripped by an atmospheric pressure micro plasma technique, thereby preparing a two-dimensional sheet quickly and efficiently. material;

The method specifically includes the following steps:

(1) Construction of the device: the device is composed of an anode, a cathode, a solvent and a high-voltage power source; wherein the anode adopts a needle-shaped metal electrode and is vertically placed above the solvent, and the metal electrode is connected to the positive output of the high-voltage power source, and the cathode The material crystal is used and immersed in a solvent to be connected to a negative polarity output of the high voltage power source; and the metal electrode is a hollow structure;

(2) Stripping of the material: an inert discharge gas is introduced into the hollow metal electrode, and then the DC high-voltage power source is turned on to adjust the discharge voltage so that the plasma is generated between the tip of the metal electrode and the liquid surface of the solvent, and the treatment is performed to obtain two Dimensional sheet material.

The material is selected from the group consisting of black phosphorus, graphene, boron nitride, molybdenum disulfide, tungsten disulfide, tungsten diselenide, antimony disulfide, titanium disulfide, antimony disulfide, antimony telluride or antimony telluride. One.

The solvent is a nitrogen-containing organic solvent, preferably dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, N-octylpyrrolidone, 1,3-dimethyl One or more of 2-imidazolidinone, N,N-dimethylformamide.

The discharge gas is one or more of argon gas, helium gas or ammonia gas.

The distance between the tip of the anode electrode and the liquid level of the solvent is between 0.1 and 5.0 mm.

The discharge gas flow rate is between 10 and 500 sccm, preferably between 30 and 300 sccm.

The distance between the anode and the cathode is 10 to 50 mm.

The discharge voltage of the high voltage power supply is 300 to 5000V.

The plasma processing time is 10 to 600 s (What is the meaning of this time? How much can be obtained in this time? Two-dimensional materials? Is the time proportional to the amount of material obtained? ).

The prepared two-dimensional crystalline sheet material has an average sheet thickness of from 1 to 100 nm and an average size of from 100 nm to 50 μm.

The invention is based on atmospheric pressure plasma technology, utilizing electrons, ions, excited state atoms in plasma and plasma to form H ⁺ , NH ₄ ^{+ ,} etc. formed by solution, black phosphorus, graphene, boron nitride, disulfide Materials such as molybdenum, tungsten disulfide, tungsten diselenide, antimony disulfide, titanium disulfide, antimony disulfide, antimony telluride and antimony telluride are rapidly and effectively intercalated, resulting in expansion of single or multi-layer materials. At the same time, under the activation of the plasma, the solution can form and generate a large number of bubbles, thereby further stripping the material to form a single layer or a small layer of crystalline material. In the preparation process, the present invention can control the preparation yield and rate of single-layer or small-layer two-dimensional crystal materials by adjusting parameters such as discharge voltage, discharge interval, gas flow rate, and electrode distance.

Beneficial effects:

Compared with the prior art, the technical method of the invention is novel, unique, green, and simple in operation, and does not need to use complicated and expensive equipment and additional chemical reagents, and utilizes the characteristics of atmospheric plasma and its interaction with the solution, and is fast and efficient. The completion of the two-dimensional material, in particular, effectively avoids the oxidation of two-dimensional black phosphorus by air or water, and is especially suitable for the preparation of black phosphorus nanosheet material. Moreover, the invention can adjust and control the size and the number of layers of the crystal sheet according to different application fields, which has important practical significance for the preparation and application of the two-dimensional crystal sheet and the composite material thereof.

The two-dimensional nanoflakes and composite materials thereof according to the present invention are not limited in their application, and can be applied to fields currently known such as photovoltaic devices, biomedicine, tumor therapy, photovoltaic devices, and the like. And it is also readily apparent to those skilled in the art based on their physical and chemical properties to apply them to other possible fields.

DRAWINGS

1 is a photomicrograph of a two-dimensional black phosphorus nanoflake prepared in Example 1.

2 is a transmission electron micrograph of a two-dimensional black phosphorus nanoflake prepared in Example 2.

3 is a Raman spectrum of a two-dimensional black phosphorus nanoflake prepared in Example 2.

4 is a photomicrograph of graphene nanoflakes prepared in Example 6.

5 is a Raman spectrum of graphene nanoflakes prepared in Example 6.

Detailed ways

The invention is further illustrated below in conjunction with specific embodiments. It is to be understood that the examples are not intended to limit the scope of the invention. In addition, it should be understood that various changes and modifications may be made by those skilled in the art in the form of the present invention.

Example 1

A method for preparing a two-dimensional black phosphorus material by using atmospheric pressure plasma is to construct a black phosphorus crystal stripping device for a cathode, and the black phosphorus crystal is stripped by an atmospheric pressure micro plasma technology, thereby rapidly and efficiently preparing two Dihesive phosphorus nanoflake material. In this embodiment, a hollow stainless steel capillary having an inner diameter of 0.2 mm and an outer diameter of 1.6 mm is used as an anode, and black phosphorus is used. The crystal serves as a cathode, and N-methylpyrrolidone is used as a solution and a DC high-voltage power source to constitute a preparation device. Wherein, the anode is vertically placed above the solution, the tip of the electrode is 0.1 mm from the liquid surface, the metal electrode is connected to the positive output of the high voltage power source; the cathode is made of black phosphorus crystal material, and is immersed in the solution, and connected to the negative polarity output of the high voltage power supply. At the same time, the distance between the anode and the cathode was kept at 50 mm. Using argon as the discharge gas, adjusting the flow rate of the argon gas to 30 sccm, introducing argon gas into the stainless steel capillary, and then starting the DC high voltage power supply, adjusting the discharge voltage to 300 V, so that the plasma is generated between the capillary and the solution level, and the treatment is performed. The time is 600s, and the two-dimensional black phosphorus nanosheet material can be obtained. Figure 1 shows a micrograph of the prepared two-dimensional black phosphorus material, which can be seen to have a uniform size distribution.

Example 2

A method for preparing a two-dimensional black phosphorus material by using atmospheric pressure plasma is to construct a cathode black phosphorus crystal stripping device by using atmospheric pressure microplasma technology to peel off black phosphorus crystals, thereby preparing two fast and efficient technologies. Dihesive phosphorus nanoflake material. In the present embodiment, a stainless steel capillary having an inner diameter of 0.4 mm and an outer diameter of 2.5 mm was used as an anode, a black phosphorus crystal was used as a cathode, and dimethylformamide was used as a solution and a DC high-voltage power source to constitute a preparation device. Wherein, the anode is vertically placed above the solution, the tip of the electrode is 1.5 mm from the liquid surface, the metal electrode is connected to the positive output of the high voltage power source; the cathode is made of black phosphorus crystal material, and is immersed in the solution, and connected to the negative polarity output of the high voltage power supply. At the same time, the distance between the anode and the cathode was kept at 10 mm. Using argon as the discharge gas, adjusting the flow rate of the argon gas to 50 sccm, introducing argon gas into the stainless steel capillary, and then starting the DC high voltage power supply, adjusting the discharge voltage to 1000 V, so that the plasma is generated between the capillary and the solution level, and the treatment is performed. The time is 120s, and the two-dimensional black phosphorus nanosheet material can be obtained.

Figure 2 is a transmission electron micrograph of the prepared two-dimensional black phosphorus material. It can be seen that the thickness of the two-dimensional black phosphorus material in the photograph is very uniform, and both are thin layers, and the substrate is lining. The degree is relatively close. Generally speaking, the thickness of the single layer of two-dimensional black phosphorus is about 1-2 nm. When it is close to the substrate contrast in the transmission electron microscope, it can be shown that the two-dimensional black phosphorus is a single layer. In the examples, the average thickness of the black phosphorus layer is about 2 nm. At the same time, it can be seen that the size of the two-dimensional black phosphorus material is larger, the smallest sample has a size of about 2 μm, and the other samples are far larger than 2 μm.

Figure 3 shows the Raman spectrum of the prepared two-dimensional black phosphorus material. It can be seen that the characteristic peaks of 360.4 cm ^-1 , 437.0 cm ^-1 and 464.3 cm ^-1 indicate the presence of two-dimensional black phosphorus. At the same time, it has been shown that as the thickness of the two-dimensional black phosphorus decreases, the Raman peak of the black phosphorus sheet moves toward a high wave number. The characteristic peak of 520.5 cm ^-1 in the figure confirms the existence of this phenomenon, indicating that the prepared two-dimensional black phosphorus has a thinner number of layers.

Example 3

A method for preparing a two-dimensional black phosphorus material by using atmospheric pressure plasma is to construct a cathode black phosphorus crystal stripping device by using atmospheric pressure microplasma technology to peel off black phosphorus crystals, thereby preparing two fast and efficient technologies. Dihesive phosphorus nanoflake material. In the present embodiment, a stainless steel capillary having an inner diameter of 0.3 mm and an outer diameter of 5.0 mm was used as an anode, a black phosphorus crystal was used as a cathode, and N,N-dimethylformamide was used as a solution and a DC high-voltage power source to constitute a preparation apparatus. Wherein the anode is placed vertically Above the solution, the tip of the electrode is 5.0 mm from the liquid surface, and the metal electrode is connected to the positive output of the high voltage power supply; the cathode is made of black phosphorus crystal material and immersed in the solution, and connected to the negative polarity output of the high voltage power supply. At the same time, the distance between the anode and the cathode was kept at 50 mm. Using helium as the discharge gas, adjusting the helium gas flow rate to 300sccm, introducing argon gas into the stainless steel capillary tube, then starting the DC high voltage power supply, adjusting the discharge voltage to 5000V, so that the plasma is generated between the capillary and the solution level, and the treatment is performed. At a time of 10 s, a two-dimensional black phosphorus nanoflake material can be obtained.

Example 4

A method for preparing a two-dimensional black phosphorus material by using atmospheric pressure plasma is to construct a cathode black phosphorus crystal stripping device by using atmospheric pressure microplasma technology to peel off black phosphorus crystals, thereby preparing two fast and efficient technologies. Dihesive phosphorus nanoflake material. In the present embodiment, a stainless steel capillary having an inner diameter of 0.2 mm and an outer diameter of 6.0 mm was used as an anode, a black phosphorus crystal was used as a cathode, and dimethylacetamide was used as a solution and a DC high-voltage power source to constitute a preparation device. Wherein, the anode is vertically placed above the solution, the tip of the electrode is 3.0 mm from the liquid surface, the metal electrode is connected to the positive output of the high voltage power source; the cathode is made of black phosphorus crystal material, and is immersed in the solution, and connected to the negative polarity output of the high voltage power supply. At the same time, the distance between the anode and the cathode was kept at 20 mm. A mixture of helium and ammonia in a volume mixing ratio of 1:0.05 is used as a discharge gas, the flow rate of the mixed gas is adjusted to 100 sccm, a mixture gas is introduced into the stainless steel capillary tube, and then a DC high voltage power source is started to adjust the discharge voltage to 3500 V. The plasma is generated between the capillary and the solution surface, and the treatment time is 90 s to obtain a two-dimensional black phosphorus nanosheet material.

Example 5

A method for preparing a two-dimensional black phosphorus material by using atmospheric pressure plasma is to construct a cathode black phosphorus crystal stripping device by using atmospheric pressure microplasma technology to peel off black phosphorus crystals, thereby preparing two fast and efficient technologies. Dihesive phosphorus nanoflake material. In the present embodiment, a stainless steel capillary having an inner diameter of 0.5 mm and an outer diameter of 8.0 mm was used as an anode, a black phosphorus crystal was used as a cathode, and 1,3-dimethyl-2-imidazolidinone was used as a solution and a DC high-voltage power source to constitute a preparation apparatus. Wherein, the anode is vertically placed above the solution, the tip of the electrode is 1.5 mm from the liquid surface, the metal electrode is connected to the positive output of the high voltage power source; the cathode is made of black phosphorus crystal material, and is immersed in the solution, and connected to the negative polarity output of the high voltage power supply. At the same time, the distance between the anode and the cathode was kept at 15 mm. A mixture of argon and ammonia in a volume mixing ratio of 1:0.01 is used as a discharge gas, the flow rate of the mixed gas is adjusted to 150 sccm, a mixture gas is introduced into the stainless steel capillary tube, and then a DC high-voltage power source is started to adjust the discharge voltage to 2500 V to make the plasma The body is produced between the capillary and the solution surface, and the treatment time is 150 s to obtain a two-dimensional black phosphorus nanosheet material.

Example 6

A method for preparing graphene by atmospheric pressure plasma is to construct a stripping device with a cathode as a graphite crystal by using atmospheric pressure microplasma technology to peel off the graphite crystal, thereby rapidly and efficiently preparing two-dimensional graphene nanometers. Sheet material. In the present embodiment, a stainless steel capillary having an inner diameter of 0.1 mm and an outer diameter of 1.5 mm was used as an anode, a graphite crystal was used as a cathode, N,N-dimethylformamide was used as a solution, and a DC high-voltage power source constituted a preparation device. Wherein the anode is placed vertically Above the solution, the tip of the electrode is 2.0 mm from the liquid surface, and the metal electrode is connected to the positive output of the high voltage power supply; the cathode is made of graphite crystal material and immersed in the solution, and connected to the negative polarity output of the high voltage power supply. At the same time, the distance between the anode and the cathode was kept at 25 mm. A mixture of helium and ammonia in a volume mixing ratio of 1:0.05 is used as a discharge gas, the flow rate of the mixed gas is adjusted to 200 sccm, a mixture gas is introduced into the stainless steel capillary tube, and then a DC high-voltage power source is started to adjust the discharge voltage to 800 V to make the plasma The body is produced between the capillary and the solution surface, and the treatment time is 120 s to obtain a graphene nanosheet material. Figure 4 is a photomicrograph of the prepared graphene material. It can be seen that the graphene material in the photograph has a thin sheet and is large in size. Figure 5 shows a Raman spectrum of the prepared graphene material. It can be seen that the characteristic peak confirms the presence of graphene material.

In the preparation method of the present invention, the technical parameters have a key role in the preparation of the two-dimensional material. For example, the distance between the anode and the cathode, when other conditions are the same, the smaller the distance, the more two-dimensional nanosheets having a thickness of less than 10 nm can be obtained. This is because when the distance is small, the loss of plasma energy transmission is small, and more electrons, ions, radicals, excited atoms and plasmas formed by the action of H ⁺ , NH ₄ ⁺ etc. will act on the surface of the material. To quickly peel off. In addition, the preparation efficiency of the method is greatly affected by the thickness and defects of the crystal material. When the thickness of the material is thin and there are defects, the active particles in the plasma and its activated solution can act better on the surface of the material, and the presence of defects can induce the diffusion and action of the active particles into the material, so the preparation efficiency is more high.

Claims

A method for preparing a two-dimensional material by using atmospheric pressure plasma, characterized in that a stripping device in which a cathode is a material crystal is constructed, and the crystal is stripped by an atmospheric pressure micro plasma technique, thereby preparing a two-dimensional sheet quickly and efficiently. material;

The method specifically includes the following steps:

(1) Construction of the device: the device is composed of an anode, a cathode, a solvent and a high-voltage power source; wherein the anode adopts a needle-shaped metal electrode and is vertically placed above the solvent, and the metal electrode is connected to the positive output of the high-voltage power source, and the cathode The material crystal is used and immersed in a solvent to be connected to a negative polarity output of the high voltage power source; and the metal electrode is a hollow structure;

(2) Stripping of the material: an inert discharge gas is introduced into the hollow metal electrode, and then the DC high-voltage power source is turned on to adjust the discharge voltage so that the plasma is generated between the tip of the metal electrode and the liquid surface of the solvent, and the treatment is performed to obtain two Dimensional sheet material.
The method for preparing a two-dimensional material by using atmospheric pressure plasma according to claim 1, wherein the material is selected from the group consisting of black phosphorus, graphene, boron nitride, molybdenum disulfide, tungsten disulfide, and selenium. Any of tungsten, disulfide, titanium disulfide, antimony disulfide, antimony telluride or antimony telluride.
The method for preparing a two-dimensional material by atmospheric pressure plasma according to claim 1 or 2, wherein the solvent is a nitrogen-containing organic solvent, preferably dimethylformamide or dimethylacetate. One or more of amide, N-methylpyrrolidone, N-vinylpyrrolidone, N-octylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, N,N-dimethylformamide .
The method for preparing a two-dimensional material by using atmospheric pressure plasma according to claim 1, wherein the discharge gas is one or more of argon gas, helium gas or ammonia gas.
The method for preparing a two-dimensional material by atmospheric pressure plasma according to claim 1 or 2, wherein the distance between the tip of the anode electrode and the liquid surface of the solvent is between 0.1 and 5.0 mm.
A method of preparing a two-dimensional material by atmospheric pressure plasma according to claim 1 or 4, wherein the discharge gas flow rate is between 10 and 500 sccm, preferably between 30 and 300 sccm.
A method of preparing a two-dimensional material by atmospheric pressure plasma according to claim 1, wherein the distance between the anode and the cathode is 10 to 50 mm.
The method for preparing a two-dimensional material by atmospheric pressure plasma according to claim 1 or 7, wherein the discharge voltage of the high voltage power source is 300 to 5000V.
The method for preparing a two-dimensional material by atmospheric pressure plasma according to claim 1, wherein the plasma treatment time is 10 to 600 s.
The method for preparing a two-dimensional material by atmospheric pressure plasma according to claim 1, wherein the prepared two-dimensional sheet material has an average sheet thickness of 1 to 100 nm and an average size of 100 nm to 50 μm.
The use of the two-dimensional material prepared by the preparation method according to any one of claims 1 to 10 in the field of optoelectronic devices, biomedicine, tumor treatment, and photovoltaic devices.