WO2020187332A1

WO2020187332A1 - Method for electrocatalytic preparation of defect-free disorderly stacked graphene nanofilms and application

Info

Publication number: WO2020187332A1
Application number: PCT/CN2020/083030
Authority: WO
Inventors: 彭蠡; 高超
Original assignee: 杭州高烯科技有限公司; 浙江大学
Priority date: 2019-03-17
Filing date: 2020-04-02
Publication date: 2020-09-24
Also published as: CN109928387A

Abstract

A method for electrocatalytic preparation of defect-free disorderly stacked graphene nanofilms. The graphene nanofilm is obtained by thermally and electrically treating an independent self-supported graphene film. The steps are as follows: (1) preparing an independent self-supported graphene film, the number of graphene films in the thickness direction being not greater than 200; and (2) gradually heating the graphene film to 2000°C, the heating speed being not greater than 60°C/min, maintaining the temperature for 1-2 h, then electrifying the film, the current magnitude being 1-20 A, and maintaining the state for 1-4 h.

Description

Method and application for electrocatalytic preparation of defect-free disordered layer stacking graphene nanometer film

Technical field

The invention relates to a high-performance nano material and a preparation method thereof, in particular to a method and application for electrocatalytic preparation of a defect-free random-layer stacked graphene nano-film. By this method, a defect-free random-layer stacked graphene nano film with nano-level thickness can be obtained membrane.

Background technique

In 2010, two professors, Andre GeiM and Konstantin Novoselov, from the University of Manchester in the United Kingdom, won the Nobel Prize in Physics for successfully separating stable graphene for the first time, setting off a worldwide upsurge in graphene research. Graphene has excellent electrical properties (electron mobility can reach 2×10 ⁵ cM ² /Vs at room temperature), outstanding thermal conductivity (5000W/(MK), exceptional specific surface area (2630M ² /g), and Young’s Modulus (1100GPa) and breaking strength (125GPa). Graphene's excellent electrical and thermal conductivity completely exceeds that of metal, and graphene has the advantages of high temperature resistance and corrosion resistance, and its good mechanical properties and lower density make it more Potential to replace metal in the field of electric heating materials.

The graphene film of macroscopically assembled graphene oxide or graphene nanosheets is the main application form of nano-scale graphene. The commonly used preparation methods are suction filtration, scraping, spin coating, spray coating, and dip coating. Through further high temperature treatment, the defects of graphene can be repaired, and the conductivity and thermal conductivity of graphene film can be effectively improved. It can be widely used in smart phones, smart portable hardware, tablet computers, notebook computers and other portable electronic devices. .

But at present, the thickness of the graphene film sintered at high temperature is generally more than 1um, and a lot of gas is enclosed inside. During the high-pressure pressing process, the closed pores remain in the form of folds, resulting in poor orientation and density of the graphene film. It becomes smaller, and the degree of AB stacking between layers is poor, which seriously affects the further improvement of graphene film performance. In addition, there are no reports on the preparation of nano-scale graphene films based on graphene oxide. Under normal circumstances, nano-scale graphene films generally refer to polycrystalline graphene films prepared by chemical vapor deposition methods, which are fixed on a certain substrate after being transferred by wet or dry methods, and cannot be independent in the air. support. The graphene film itself has a polycrystalline structure, and its performance is greatly affected by grain boundaries.

The most important thing is that AB-stacked graphene requires higher preparation (higher temperature and maintenance time), and non-AB structure in optoelectronic applications is more conducive to the migration of photoelectrons, and there is currently no graphene dominated by a chaotic layer stack structure membrane.

Summary of the invention

The purpose of the present invention is to overcome the shortcomings of the prior art, and provide a method and application for preparing a defect-free disordered layer stacking graphene nano-film.

The purpose of the present invention is achieved by the following technical solutions: a method for electrocatalytic preparation of defect-free disordered layer stacking graphene nano-film, the steps are as follows:

(1) Preparation of an independent and self-supporting graphene film; in the thickness direction, the number of layers of the graphene film is not more than 200;

(2) Gradually heat the graphene film to 2000°C at a rate of no more than 60°C/min for 1-2 hours, and then energize the film with a current of 1-20A for 1-4 hours.

Further, a solid transfer method is used to prepare an independent self-supporting graphene film.

Further, the solid transfer method includes the following steps:

(1.1) The graphene oxide is formulated into a graphene oxide aqueous solution with a concentration of 0.5-10ug/mL, and the mixed cellulose ester (MCE) is used as a substrate to suction and filter to form a film.

(1.2) Place the graphene oxide film attached to the MCE film in a closed container and fumigate at a high temperature of 60-100 degrees HI for 1-10 hours.

(1.3) The molten solid transfer agent is uniformly coated on the surface of the reduced graphene oxide film, and cooled at room temperature.

(1.4) Place the graphene film coated with the solid transfer agent in the good solvent of the MCE film, and etch the MCE film.

(1.5) The graphene film supported by the solid transfer agent obtained above volatilizes the solid transfer agent at a temperature at which the solid transfer agent volatilizes to obtain an independent self-supporting graphene film.

Further, the solid transfer agent is selected from the following substances, such as paraffin, aluminum chloride, iodine, naphthalene, arsenic trioxide, phosphorus pentachloride, acrylamide, ferric chloride, sulfur, red phosphorus, ammonium chloride, Ammonium bicarbonate, potassium iodide, norbornene, caffeine, melamine, water, rosin, tert-butanol, sulfur trioxide and other small molecular solid substances that can be sublimated or volatilized under certain conditions.

Further, the good solvent of the MCE film is selected from one or more of acetone, n-butanol, ethanol, and isopropanol.

Further, the independent self-supporting graphene film is prepared by the water stripping method, and the preparation method is as follows:

(1.1) The graphene film is peeled from the AAO base film, specifically: the AAO base film with the graphene film attached to the surface is placed on the water surface with the graphene film facing up; pressing the AAO base film to make The AAO basement membrane sinks, and the graphene membrane floats on the water surface.

(1.2) A substrate is used to lift the graphene film floating on the water surface from bottom to top, so that the graphene film is spread on the surface of the substrate, and there is a layer of water medium between the graphene film and the substrate.

(1.3) The substrate with the graphene film loaded on the surface is freeze-dried. The graphene film is self-supporting and separated from the substrate.

Further, the porosity of the surface of the AAO base film is not less than 40%.

Further, the substrate described in step 2 is a hydrophobic substrate.

Further, the upper surface of the substrate described in step 2 has a recessed area.

In the above step 1, the pressing position is the edge of the AAO base film. The thickness of the graphene film can reach 4 nm. The graphene film may be a graphene oxide film or a reduced graphene oxide film.

The application of defect-free random layer stacking graphene nano-film is: applied to nano-level acoustic wave generators. The said nano-level acoustic wave generator includes a substrate with a thermal conductivity of less than 200W/mK, a defect-free random-layer stacked graphene nano-membrane flat on the substrate, an electrical signal input unit and two silver glues for audio current input The two silver glue electrodes are respectively arranged on both ends of the sound wave generating film, the sound wave generating film, the two silver glue electrodes and the electrical signal input unit are connected in series to form a loop; in the defect-free disordered layer stacking graphene nano film, graphene The lamellae have a conjugated structure and are free of defects; the interlayer stacking method is disorderly stacking.

The beneficial effects of the present invention are: the present invention gradually raises the temperature of the independently self-supporting graphene film to 2000 degrees, (1-60 degrees per minute), maintains it for 1-2 hours, repairs most of the defective structure, while maintaining the graphite The state of chaotic stacking of vinyl sheets. Then energize the film to activate carbon atoms and promote the flow of carbon atoms, thereby further repairing atomic structural defects. The two work together to greatly reduce the defect structure repair temperature of the graphene film. The non-ab structure weakens the interlayer force and reduces the conduction of phonons in the vertical direction, thereby increasing the horizontal transmission and increasing the thermal conductivity in the horizontal direction. The defect-free structure facilitates the transmission of electrons and phonons, and does not form electrical resistance and thermal resistance. The fast heating and cooling rate determines that this film has excellent sound quality and high sound clarity. While ensuring transparency, the invention guarantees great electrical conductivity and mechanical load-bearing performance, and can withstand the tension of the battery during the discharge process and the flexible bending process of the battery. When used, the film is used as a photoanode, counter electrode, etc.; in comparison, graphene has a higher electron mobility, and there is no heavy metal pollution problem, which reduces costs and improves light conversion efficiency.

Description of the drawings

FIG. 1 is a schematic diagram of the structure of an independently self-supporting graphene film prepared in Example 1;

Figure 2 is a Raman diagram of the film prepared in Example 1;

Figure 3 is a TEM image of the film prepared in Example 1;

Fig. 4 is a schematic diagram of the process of peeling off the graphene film from the AAO base film.

Fig. 5 is an experimental process diagram of Example 4 AAO base film exfoliating graphene film.

6 is a photograph of the self-supporting graphene film prepared in Example 4.

7 is an atomic force microscope image of the self-supporting graphene film prepared in Example 4.

Fig. 8 is a schematic diagram of the substrate of Example 5. In the figure, 1 is a substrate with a depressed center, 2 is a graphene film, and 3 is water.

detailed description

Example 1:

(1) The graphene oxide is formulated into a graphene oxide aqueous solution with a concentration of 0.5ug/mL, and the mixed cellulose ester (MCE) is used as a substrate to suction and filter to form a film.

(2) Place the graphene oxide film attached to the MCE film in a closed container and fumigate at a high temperature of 60 degrees HI for 1 hour.

(3) Coating the melted paraffin uniformly on the surface of the reduced graphene oxide film by evaporation, casting, etc., and slowly cooling at room temperature.

(4) The graphene film coated with the solid transfer agent is slowly washed with ethanol to dissolve the MCE film.

(5) The graphene film supported by the solid transfer agent obtained above is slowly volatilized off the solid transfer agent at 120 degrees to obtain an independent self-supporting graphene film, the thickness of the graphene film is about 30 atomic layers, and the transparency is 95 %.

(6) Gradually heat the graphene film to 2000°C at a heating rate of 60°C/min for 2 hours, and then energize the film with a current of 1A and maintain it for 4 hours.

As shown in Figure 1, graphene has a few wrinkles. It can be seen in Figure 2 that the defect peak in Raman is basically absent, which proves the defect-free structure of the graphene film. Figure 3 TEM electron diffraction pattern shows that the stacking of graphene sheets is chaotic stacking. Its horizontal thermal conductivity reaches 2500W/mK, electrical conductivity reaches 1.5MS/m, and the wavelength range of photoelectric detection reaches terahertz.

Connect two electrodes on the left and right sides of the graphene film, and use a temperature control sensor to measure the temperature change of the graphene electric heating film. This kind of graphene film takes only 1.2 seconds to reach in an atmospheric environment under a DC voltage of 10V The stable temperature is 270°C. After the power is turned off, the temperature of the graphene film drops to close to room temperature within 1 second due to the excellent thermal conductivity of the graphene film. At the time T=1s, the infrared detector was used to obtain the film surface temperature distribution map. The graphene film was along the linear direction of the two electrodes, and the temperature was stable, both at about 270°C.

Lay the above graphene film 2×2cm ² flat on a polyimide substrate (thermal conductivity 0.35W/mK), coat silver glue electrodes on both ends of the graphene film, and connect the two silver glue electrodes with electrical signals respectively. The positive and negative poles of the input unit are connected to form the nano-level acoustic wave generator of the present invention. Due to the high conductivity of the film, it will violently exothermic and heat up under the condition of applied voltage. When the applied voltage is withdrawn, the heat dissipation rate of the film is extremely high. The two work together to make the film rise and fall rapidly, thereby causing the air at the film to heat up. Vibrate to make a sound. Therefore, through the auxiliary loading of 8V DC voltage, and inputting the designated audio signal through the electrical signal input unit to adjust the overall input voltage and change frequency, the determined air thermal vibration amplitude, namely the pitch, can be obtained; adjust the input signal The frequency can adjust the air thermal vibration frequency, and then the frequency of the sound can be changed to produce different sounds.

Example 2:

(1) The graphene oxide is formulated into a graphene oxide aqueous solution with a concentration of 10ug/mL, and the mixed cellulose ester (MCE) is used as a substrate to suction and filter to form a film.

(2) Place the graphene oxide film attached to the MCE film in a closed container and fumigate at a high temperature of 100 degrees HI for 10 hours.

(3) Coating the melted rosin uniformly on the surface of the reduced graphene oxide film by evaporation, casting, etc., and slowly cooling at room temperature.

(4) Place the graphene film coated with the solid transfer agent in acetone to remove the MCE film.

(5) The graphene film supported by the solid transfer agent obtained above is slowly volatilized off the rosin at 300 degrees to obtain an independent self-supporting graphene film with a thickness of about 60 atomic layers and a transparency of 10%.

(6) Gradually heat the graphene film to 2000°C at a temperature rise rate of 45°C/min for 1 hour, and then energize the film with a current of 20A for 1 hour.

After testing, there is basically no defect peak in the Raman, which proves the defect-free structure of the graphene film. The TEM electron diffraction pattern shows that the stacking of graphene sheets is chaotic stacking. Its horizontal thermal conductivity reaches 2100W/mK, electrical conductivity reaches 1.3MS/m, and the wavelength range of photoelectric detection reaches terahertz.

Connect two electrodes on the left and right sides of the graphene film, and use a temperature control sensor to measure the temperature change of the graphene electric heating film. This kind of graphene film takes only 0.9 seconds to reach in an atmospheric environment under a DC voltage of 8V The stable temperature is 280°C. After the power is turned off, the temperature of the graphene film drops to close to room temperature within 1.2 seconds due to the excellent thermal conductivity of the graphene film. The graphene film has a stable temperature along the linear direction of the two electrodes, both at about 280°C.

Example 3:

(1) The graphene oxide is formulated into a graphene oxide aqueous solution with a concentration of 8ug/mL, and the mixed cellulose ester (MCE) is used as a substrate to suction and filter to form a film.

(2) Place the graphene oxide film attached to the MCE film in a closed container and fumigate for 8 hours at 80 degrees HI.

(3) Coating the melted norbornene uniformly on the surface of the reduced graphene oxide film by evaporation, casting, etc., and slowly cooling at room temperature.

(4) Place the graphene film coated with the solid transfer agent in isopropanol to remove the MCE film.

(5) The graphene film supported by the solid transfer agent obtained above is slowly volatilized off the solid transfer agent at 100 degrees to obtain an independent self-supporting graphene film with a thickness of about 200 atomic layers.

(6) Gradually heat the graphene film to 2000°C at a rate of 20°C/min for 1 hour, and then energize the film with a current of 10A for 1 hour.

After testing, there is basically no defect peak in the Raman, which proves the defect-free structure of the graphene film. The TEM electron diffraction pattern shows that the stacking of graphene sheets is chaotic stacking. Its horizontal thermal conductivity reaches 1800W/mK, electrical conductivity reaches 1.1MS/m, and the wavelength range of photoelectric detection reaches terahertz.

Connect two electrodes on the left and right sides of the graphene film, and use a temperature control sensor to measure the temperature change of the graphene electric heating film. This kind of graphene film takes only 0.6 seconds to reach under the atmospheric environment and 8V DC voltage. The stable temperature is 300°C. After the power is turned off, the temperature of the graphene film drops to close to room temperature within 1.3 seconds due to the excellent thermal conductivity of the graphene film. The graphene film has a stable temperature along the linear direction of the two electrodes, both at about 300°C.

Example 4:

(1) Obtain an ultra-thin reduced graphene oxide film by controlling the concentration of the graphene solution and filtering on the AAO base membrane by suction filtration;

(2) The graphene film is peeled from the AAO base film, specifically: the AAO base film with a reduced graphene oxide film attached to the surface (with a porosity of 40%), with the graphene film facing upward, On the water surface, as shown in Figures 4 and 5a; press the edge of the AAO basement membrane, as shown in Figure 5b, the AAO basement membrane begins to sink, as shown in Figure 5c. Finally, the AAO basement membrane sinks to the bottom of the cup and the graphene membrane floats on the water surface (dashed circle) Inside), as shown in Figures 5b and 5d.

(3) Use a glass substrate with "Zhejiang University" printed on the surface to pick up the graphene film floating on the water from bottom to top, so that the graphene film is spread on the surface of the substrate, and there is a gap between the graphene film and the substrate. Layer of water medium.

(4) Freeze-dry the substrate with the graphene film on the surface. The graphene film is self-supporting, as shown in FIG. 6, and is separated from the substrate. Tested by atomic force microscope, its thickness is 4nm, as shown in Figure 7.

(5) Gradually heat the graphene film to 2000°C at a rate of 60°C/min for 2 hours, and then energize the film with a current of 20A for 1 hour.

After testing, there is basically no defect peak in the Raman, which proves the defect-free structure of the graphene film. The TEM electron diffraction pattern shows that the stacking of graphene sheets is chaotic stacking. Its horizontal thermal conductivity reaches 2700W/mK (self-heating test), and its electrical conductivity reaches 1.7MS/m. The wavelength range of photoelectric detection reaches terahertz.

Connect two electrodes on the left and right sides of the graphene film, and use a temperature control sensor to measure the temperature change of the graphene electric heating film. This kind of graphene film takes only 2 seconds to reach in an atmospheric environment and under a DC voltage of 12V. The stable temperature is 230°C. After the power is off, due to the excellent thermal conductivity of the graphene film, the film temperature drops to near room temperature within 0.5 seconds. The graphene film has a stable temperature along the line where the two electrodes are located, both at about 230°C.

Lay the above graphene film 2×2cm ² flat on a polyimide substrate (thermal conductivity 0.35W/mK), coat silver glue electrodes on both ends of the graphene film, and connect the two silver glue electrodes with electrical signals respectively. The positive and negative poles of the input unit are connected to form the nano-level acoustic wave generator of the present invention. Due to the high conductivity of the film, it will violently exothermic and heat up under the condition of applied voltage. When the applied voltage is withdrawn, the heat dissipation rate of the film is extremely high. The two work together to make the film rise and fall rapidly, thereby causing the air at the film to heat up. Vibrate to make a sound. Therefore, through the auxiliary loading of 12V DC voltage, and inputting the designated audio signal through the electrical signal input unit to adjust the overall input voltage and change frequency, the determined air thermal vibration amplitude, namely the pitch, can be obtained; adjust the input signal The frequency can adjust the air thermal vibration frequency, and then the frequency of the sound can be changed to produce different sounds.

Example 5

(1) By controlling the concentration of the graphene solution, the ultra-thin graphene oxide film is obtained by suction filtration on the AAO basement membrane;

(2) Peeling the graphene film from the AAO base film, specifically: the AAO base film (porosity 60%) with the graphene oxide film attached to the surface is placed with the graphene film facing upwards. On the water surface, press the edge of the AAO basement membrane, the AAO basement membrane began to sink, and finally, the AAO basement membrane sank to the bottom of the cup, the graphene membrane floated on the water surface, and the graphene membrane was successfully peeled off.

(3) Use a hydrophilic silicon substrate with "Zhejiang University" printed on the surface (the silicon surface is treated with hydrophilicity, the center is recessed, as shown in Figure 8) to lift the graphene film floating on the water from bottom to top, making the graphite The olefin film is laid flat on the center of the substrate, and the graphene film and the center of the depression have an aqueous medium.

(4) Freeze-dry the substrate with the graphene film on the surface. The graphene film is self-supporting and separated from the substrate. Tested by atomic force microscope, its thickness is 14nm.

(5) Gradually heat the graphene film to 2000°C at a rate of 4°C/min for 2 hours, and then energize the film with a current of 1A and maintain it for 4 hours.

After testing, there is basically no defect peak in the Raman, which proves the defect-free structure of the graphene film. The TEM electron diffraction pattern shows that the stacking of graphene sheets is chaotic stacking. Its horizontal thermal conductivity reaches 2600W/mK, electrical conductivity reaches 1.5MS/m; the wavelength range of photoelectric detection reaches terahertz.

It should be noted that the suction filtration method is currently recognized as the most uniform method for preparing graphene membranes. Under a certain amount of suction filtrate, the concentration can be adjusted to control the thickness of the graphene membrane, and the minimum thickness can be a layer of graphene As the concentration of graphene increases, under pressure, the newly added graphene gradually fills the gaps of the first layer of graphene, so that the first layer of graphene is gradually filled completely, and then develops into the second layer, repeating the above In the step, a graphene nano film with a thickness spanning from 2 to tens of thousands of graphene layers can be prepared. Therefore, those skilled in the art can obtain a graphene film with a thickness of 4 nm through simple adjustment of experimental parameters.

Connect two electrodes on the left and right sides of the graphene film, and use a temperature control sensor to measure the temperature change of the graphene electric heating film. This kind of graphene film takes only 0.8 seconds to reach in an atmospheric environment under a DC voltage of 10V The stable temperature is 260°C. After the power is turned off, the temperature of the graphene film drops to close to room temperature within 1.1 seconds due to the excellent thermal conductivity of the graphene film. The graphene film has a stable temperature along the linear direction of the two electrodes, both at about 270°C.

Lay the above graphene film 2×2cm ² flat on a polyimide substrate (thermal conductivity 0.35W/mK), coat silver glue electrodes on both ends of the graphene film, and connect the two silver glue electrodes with electrical signals respectively. The positive and negative poles of the input unit are connected to form the nano-level acoustic wave generator of the present invention. Due to the high conductivity of the film, it will violently exothermic and heat up under the condition of applied voltage. When the applied voltage is withdrawn, the heat dissipation rate of the film is extremely high. The two work together to make the film rise and fall rapidly, thereby causing the air at the film to heat up. Vibrate to make a sound. Therefore, through the auxiliary loading of 10V DC voltage and inputting the designated audio signal through the electrical signal input unit to adjust the overall input voltage and change frequency, a certain air thermal vibration amplitude, namely pitch, can be obtained; adjust the input signal The frequency can adjust the air thermal vibration frequency, and then the frequency of the sound can be changed to produce different sounds.

Claims

An electrocatalytic method for preparing defect-free disordered layer stacking graphene nano-membrane is characterized in that the steps are as follows:

(1) Preparation of an independent and self-supporting graphene film; in the thickness direction, the number of layers of the graphene film is not more than 200;

(2) Gradually heat the graphene film to 2000°C at a rate of no more than 60°C/min for 1-2 hours, and then energize the film with a current of 1-20A for 1-4 hours.
The preparation method according to claim 1, wherein the independent self-supporting graphene film is prepared by a solid transfer method.
The method according to claim 2, wherein the solid transfer method comprises the following steps:

(1.1) The graphene oxide is formulated into a graphene oxide aqueous solution with a concentration of 0.5-10ug/mL, and the mixed cellulose ester (MCE) is used as a substrate to suction and filter into a film;

(1.2) Place the graphene oxide film attached to the MCE film in a closed container and fumigate at a high temperature of 60-100 degrees HI for 1-10 hours;

(1.3) Coat the molten solid transfer agent uniformly on the surface of the reduced graphene oxide film and cool it at room temperature;

(1.4) Place the graphene film coated with the solid transfer agent in the good solvent of the MCE film, and etch the MCE film;

(1.5) The graphene film supported by the solid transfer agent obtained above volatilizes the solid transfer agent at a temperature at which the solid transfer agent volatilizes to obtain an independent self-supporting graphene film.
The method of claim 3, wherein the solid transfer agent is selected from the group consisting of paraffin, aluminum chloride, iodine, naphthalene, arsenic trioxide, phosphorus pentachloride, acrylamide, iron trichloride, Sulfur, red phosphorus, ammonium chloride, ammonium bicarbonate, potassium iodide, norbornene, caffeine, melamine, water, rosin, tert-butanol, sulfur trioxide and other small molecular solid substances that can be sublimated or volatilized under certain conditions The good solvent of the MCE film is selected from one or more of acetone, n-butanol, ethanol, and isopropanol.
The method according to claim 1, wherein the independent self-supporting graphene film is prepared by a water stripping method, and the preparation method is as follows:

(1.1) The graphene film is peeled from the AAO base film, specifically: the AAO base film with the graphene film attached to the surface is placed on the water surface with the graphene film facing up; pressing the AAO base film to make The AAO basement membrane sinks and the graphene membrane floats on the water;

(1.2) Use a substrate to lift the graphene film floating on the water surface from bottom to top, so that the graphene film is spread on the surface of the substrate, and there is a layer of water medium between the graphene film and the substrate;

(1.3) The substrate with the graphene film loaded on the surface is freeze-dried. The graphene film is self-supporting and separated from the substrate.
The method according to claim 5, wherein the porosity of the surface of the AAO base film is not less than 40%.
The method according to claim 5, wherein the substrate in step 2 is a hydrophobic substrate.
The method according to claim 5, wherein the upper surface of the substrate in step 2 has a recessed area.
The application of the graphene nano-film prepared by the method of claim 1, wherein the application is: applied to a nano-level acoustic wave generator; the nano-level acoustic wave generator includes a thermal conductivity of less than 200W/ mK substrate, defect-free disordered layer stacking graphene nano-membrane laid on the substrate, as well as an electrical signal input unit and two silver glue electrodes for audio current input. The two silver glue electrodes are respectively arranged at both ends of the sound wave generating film , The sound wave generating film, two silver glue electrodes and the electrical signal input unit are connected in series to form a loop.