CN117720101A - Graphene film containing folds and preparation method thereof - Google Patents

Abstract

The invention relates to a graphene film containing wrinkles and a preparation method thereof, which includes the following steps: (1) using a chemical vapor deposition method to prepare a single-layer graphene on the surface of a metal substrate; (2) spin-coating a layer of Layer a polymer support and heat it to condense the polymer support; (3) Use an ion etchant to etch the metal substrate; (4) After the metal substrate is etched, use a wet transfer method to transfer it to the substrate to be used, and remove the After adding the molecular support, a graphene film containing wrinkles is finally obtained. Compared with the existing technology, the present invention uses physical methods to prepare a wrinkle-containing graphene film that does not contain other functional groups and does not contain defects. The process is simple and the preparation time is greatly shortened.

Description

A kind of graphene film containing wrinkles and preparation method thereof

Technical field

The invention belongs to the technical field of two-dimensional nanomaterials, and in particular relates to a graphene film containing wrinkles and a preparation method thereof.

Background technique

Graphene is a new material in which carbon atoms connected by sp ² hybridization are closely packed into a single-layer two-dimensional honeycomb lattice structure. Because of its excellent optical, thermal, mechanical and other properties, it has been used in various application fields of materials. have attracted much attention and are often used in the preparation of composite materials. Introducing wrinkles to the surface of the flat two-dimensional material graphene to make it not completely flat will cause changes in the physical properties of the material. Graphene containing wrinkles has been found to have the potential to be used in the production of pressure sensors, water filtration membranes, and ultrasonic sensors. The scope of use of materials such as hydrophobic surfaces is also expanding day by day.

Currently, chemical methods are generally used to prepare wrinkled graphene films using redox graphene. For graphene oxide or redox graphene, its surface contains a large number of functional groups, and there are also defects on the surface. It is not pure carbon atoms connected by sp ² hybridization that are closely packed into a single-layer two-dimensional honeycomb lattice structure. This will change the physical properties of the wrinkled graphene film and directly affect the use effect. Therefore, it is still necessary to develop a wrinkled graphene film with an intact and defect-free surface.

Contents of the invention

The purpose of the present invention is to provide a graphene film containing wrinkles and a preparation method thereof in order to obtain a wrinkled graphene film with a complete and defect-free surface.

The object of the present invention can be achieved through the following technical solutions:

A method for preparing a wrinkle-containing graphene film, including the following steps:

(1) Use chemical vapor deposition to prepare single-layer graphene on the surface of a metal substrate;

(2) Spin-coat a polymer support on the surface of single-layer graphene, and heat to condense the polymer support;

(3) Use ion etchant to etch the metal substrate;

(4) After etching the metal substrate, use a wet transfer method to transfer it to the substrate to be used. After removing the polymer support, a graphene film containing wrinkles is finally obtained.

Further, in step (1), the chemical vapor deposition method is to heat and decompose the gas containing the carbon source on the metal substrate, so that the decomposed carbon is deposited on the metal substrate to form a single-layer graphene film.

Further, in step (1), the metal substrate includes one of copper or nickel, preferably copper.

Further, in step (2), the rotation speed of the spin coating is 1500-2500rpm, preferably 1500-2000rpm.

Further, in step (2), the spin coating time is 25-35s, preferably 30s.

Further, in step (2), the polymer support is a rosin polymer gel.

Further, the rosin polymer gel is obtained by heating and coagulating a 45-55 wt% rosin solution, and the rosin concentration is preferably 50 wt%.

Further, in step (2), the heating temperature is 35-45°C, preferably 40°C.

Further, in step (2), the heating time is 10-20 min, preferably 15 min.

Furthermore, in step (2), the heating causes the rosin polymer gel to coagulate without solidifying.

Further, in step (3), the ion etching agent is FeCl ₃ solution.

Further, in step (3), the concentration of the ion etching agent is 0.3-0.5g/ml, preferably 0.4g/ml.

Further, in step (4), the wet transfer method is to separate the composite support of the polymer support and graphene from the metal substrate after etching and dissolving the metal substrate, and then combine it with the substrate material to be used after washing. .

Further, in step (4), the substrate to be used includes one or more of silicon dioxide, polydimethylsiloxane or polymethylmethacrylate, preferably silicon dioxide.

Further, in step (4), acetone is used to remove the polymer support.

The invention also provides a graphene film containing wrinkles prepared by the above preparation method.

Compared with the prior art, the present invention has the following beneficial effects:

(1) In the present invention, rosin is used as a polymer support material and is spin-coated on the surface of graphene, and then a graphene film with a pure and defect-free surface is prepared by wet transfer. By controlling comprehensive conditions such as the rosin content, the spin coating process, and the ambient temperature during the condensation process, the rosin can quickly condense to reach the minimum condition that supports graphite from cracking (without waiting for complete solidification), so that graphene films containing wrinkles can be effectively prepared. .

(2) The rosin selected in the present invention can quickly condense within 10-20 minutes to reach the minimum condition to support graphite from cracking, while it takes at least several hours to condense under natural conditions. The invention greatly shortens the preparation time and improves the efficiency of the preparation process.

(3) The present invention does not need to use graphene oxide or redox graphene with a large number of functional groups and defects on the surface, but uses pure carbon atoms connected by sp ² hybridization to be closely packed into a single-layer two-dimensional honeycomb lattice structure. The surface has no functional groups and no defects.

(4) The present invention does not need to use chemical methods to prepare wrinkled graphene films, but uses physical methods to form wrinkled graphene films. The preparation process is simple and is expected to be applied to large-scale industrial production.

Description of the drawings

Figure 1 is an optical microscope image of a graphene film containing wrinkles on the surface of a 300 nm thick silicon dioxide wafer in Example 1 of the present invention.

Figure 2 is a Raman spectrum chart of Example 1 of the present invention.

Figure 3 is an optical microscope image of the graphene film of Comparative Example 1 on the surface of a 300nm thick silicon dioxide wafer.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention and provides detailed implementation modes and specific operating procedures. However, the protection scope of the present invention is not limited to the following embodiments.

Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise stated, the reagents and materials used in the following examples are all commercially available and of analytical grade. Among them, the rosin (CAS: 8050-09-7) was selected from Alfa Aesar, and an ordinary spin coater was used for spin coating.

Example 1:

(1) Dissolve rosin in the ethyl lactate solution at a concentration of 50wt%, use a dropper to absorb a small amount of the solution, drop it on the surface of the copper foil on which graphene is grown, and spin-coat evenly in a spin-coating machine at a speed of 1500 rpm. The time is 30s. Among them, the copper foil with graphene grown is grown by the chemical vapor deposition method. Specifically, the copper foil is placed in a quartz tube, methane and hydrogen are introduced, heated to 1050°C, the hydrogen flow rate is set to 3 sccm, and the methane flow rate is introduced. The temperature is 54 sccm, and the pressure is maintained at 120 Pa. After heating for 4 minutes, adjust the pressure to 600 Pa and continue the reaction for 1 minute. After natural cooling, a copper foil with a single layer of graphene grown is obtained.

(2) Place the copper foil spin-coated with rosin gel on a heating table at 40°C for 15 minutes to obtain a rosin/graphene/copper foil composite material;

(3) Put the rosin/graphene/copper foil into a 0.4g/ml FeCl ₃ solution. The rosin/graphene/copper foil floats on the surface of the FeCl ₃ solution. FeCl ₃ reacts with Cu to etch the copper foil;

(4) After the copper foil is completely etched, transfer the rosin/graphene to the surface of deionized water using a glass slide, and perform the transfer operation with deionized water several times to clean the excess FeCl ₃ solution. After cleaning, transfer To the surface of silicon dioxide wafer with a thickness of 300nm;

(5) Fully soak in acetone (analytical grade, 99%) to remove rosin, and then dry under nitrogen flow to obtain a graphene film containing wrinkles.

Comparative example 1:

(1) Dissolve rosin in the ethyl lactate solution at a concentration of 30wt%, and spin-coat it on the surface of the copper foil with graphene grown at a rotation speed of 1500rpm. The spin-coating time is 30s.

(2) Place the copper foil spin-coated with rosin gel on a heating table at 40°C for 15 minutes to obtain a rosin/graphene/copper foil composite material;

(3) Put the rosin/graphene/copper foil into a 0.4g/ml FeCl ₃ solution. The rosin/graphene/copper foil floats on the surface of the FeCl ₃ solution. FeCl ₃ reacts with Cu to etch the copper foil;

(4) After the copper foil is completely etched, use the wet transfer method to transfer it to the surface of the silicon dioxide wafer with a thickness of 300nm;

(5) Fully soak in acetone (analytical grade, 99%) to remove rosin, and then dry under nitrogen flow to obtain a graphene film.

Figure 1 is an optical microscope picture of the surface of the silicon dioxide wafer in Example 1. As can be seen from the figure, Example 1 successfully prepared a defect-free graphene film containing wrinkles.

Figure 2 shows the Raman spectrum of the single-layer graphene and the Raman spectrum of the wrinkled graphene in Figure 1. The laser is focused on the wrinkles and characterized by Raman as multilayer graphene, that is, a graphene film containing wrinkles.

Figure 3 is an optical microscope image of Comparative Example 1 on the surface of a silica wafer. It can be seen from the figure that this comparative example has obvious holes, and a complete graphene film cannot be obtained, and a defect-free and wrinkled graphene film cannot be formed. Therefore, the concentration of rosin has an important influence on the preparation of the final wrinkled graphene.

Comparative example 2:

(1) Dissolve rosin in the ethyl lactate solution at a concentration of 50wt%, and spin-coat it on the surface of the copper foil growing graphene at a rotation speed of 1500rpm. The spin-coating time is 30s.

(2) Place the copper foil spin-coated with rosin gel on a heating table at 90°C for 15 minutes to obtain a rosin/graphene/copper foil composite material;

(3) Put the rosin/graphene/copper foil into a 0.4g/ml FeCl ₃ solution. The rosin/graphene/copper foil floats on the surface of the FeCl ₃ solution. FeCl ₃ reacts with Cu to etch the copper foil.

However, as the copper foil is etched, the rosin/graphene heated at high temperature is completely solidified and physically cracks directly in the FeCl ₃ solution. It cannot completely float on the surface of the FeCl ₃ solution, and the wet transfer operation cannot be completed, nor can it produce any traces. Crumpled graphene.

Comparative example 3:

(1) Dissolve rosin in the ethyl lactate solution at a concentration of 50wt%, and spin-coat it on the surface of the copper foil on which graphene is grown at a rotation speed of 1200 rpm. The spin-coating time is 30 seconds.

(2) Place the copper foil spin-coated with rosin gel on a heating table at 40°C for 15 minutes to obtain a rosin/graphene/copper foil composite material;

(3) Put the rosin/graphene/copper foil into a 0.4g/ml FeCl ₃ solution. The rosin/graphene/copper foil floats on the surface of the FeCl ₃ solution. FeCl ₃ reacts with Cu to etch the copper foil;

(4) After the copper foil is completely etched, use the wet transfer method to transfer it to the surface of the silicon dioxide wafer with a thickness of 300nm.

However, due to the low speed of spin-coated rosin, the rosin content in the rosin/graphene/copper foil is still in a gel state and is not fully condensed. The wet transfer operation cannot be completed and wrinkled graphene cannot be produced. .

The above description of the embodiments is to facilitate those of ordinary skill in the technical field to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without inventive efforts. Therefore, the present invention is not limited to the above embodiments. Based on the disclosure of the present invention, improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims (10)

1. A method for preparing a wrinkle-containing graphene film, characterized in that it includes the following steps: (1) Use chemical vapor deposition to prepare single-layer graphene on the surface of a metal substrate; (2) Spin-coat a polymer support on the surface of single-layer graphene, and heat to condense the polymer support; (3) Use ion etchant to etch the metal substrate; (4) After etching the metal substrate, use a wet transfer method to transfer it to the substrate to be used. After removing the polymer support, a graphene film containing wrinkles is finally obtained. 2. A method for preparing a wrinkle-containing graphene film according to claim 1, characterized in that in step (1), the chemical vapor deposition method is to heat and decompose a gas containing a carbon source on a metal substrate. , so that the decomposed carbon is deposited on the substrate to become a single-layer graphene film. 3. The method for preparing a wrinkle-containing graphene film according to claim 1, wherein in step (1), the substrate includes one of copper or nickel. 4. The method for preparing a wrinkle-containing graphene film according to claim 1, characterized in that in step (2), the rotation speed of the spin coating is 1500-2500 rpm, and the spin coating time is 25-35 s. . 5. The method for preparing a wrinkle-containing graphene film according to claim 1, characterized in that in step (2), the polymer support is a rosin polymer gel. 6. The method for preparing a wrinkle-containing graphene film according to claim 5, characterized in that the rosin polymer gel is obtained by heating and condensing a 45-55 wt% rosin solution. 7. The method for preparing a wrinkle-containing graphene film according to claim 1, characterized in that in step (2), the heating temperature is 35-45°C, and the heating time is 10-20 minutes. 8. The preparation method of a wrinkle-containing graphene film according to claim 1, characterized in that in step (3), the ion etchant is _FeCl solution, and the concentration of the ion etchant is 0.3 -0.5g/ml. 9. A method for preparing a wrinkle-containing graphene film according to claim 1, characterized in that in step (4), the substrate to be used includes silicon dioxide, polydimethylsiloxane or poly(dimethylsiloxane). One or more of methyl methacrylate. 10. A graphene film containing wrinkles prepared by the preparation method of any one of claims 1-9.