CN105118382A - Graphene layer, membrane material, method for preparing membrane material, and flexible display device - Google Patents

Abstract

The invention relates to the field of electronic materials. The invention discloses a graphene layer comprising a graphene film and an organic insulating film adhered to one surface of the graphene film; a hydrogen bond can be formed between the graphene film and the organic insulating film; the organic insulating film The membrane is polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic type resin. The invention also discloses a film material composed of the graphene layer and a polyimide substrate and a preparation method thereof. On the one hand, the organic insulating film can form hydrogen bonds with the graphene film in the subsequent photolithography process, and the connection is tight; on the other hand, the organic insulating film can also form a tight connection with the polyimide, so the organic insulating film effectively improves Adhesion properties of graphene to polyimide. The film material composed of graphene film, organic insulating film and polyimide substrate has good adhesion performance, and the graphene film is not easy to fall off. The film material can be applied to display devices.

Description

Graphene layer, film material, preparation method thereof and flexible display device

technical field

The invention relates to the field of electronic devices, in particular to a graphene layer, a film material, a preparation method thereof and a flexible display device.

Background technique

In recent years, flexible displays have achieved rapid development. For flexible display devices, high-quality substrates are crucial. Taking graphene as an example, graphene has 100 times higher charge mobility than silicon, 100 times higher current density than copper, outstanding thermal conductivity and chemical resistance structure, not only can realize a variety of chemical functional applications, but also has Features such as flexibility and stretchability can be synthesized and printed in a simple way. Graphene can not only be used as a substitute material for existing materials, but also can be used as a material for next-generation transistors and electrode components, so it has attracted widespread attention.

Polyimide (PI) has the advantages of excellent mechanical properties, stable performance, and high temperature resistance. It has great application prospects whether it is used as a structural material or as a functional material. Since the PI film is a high-temperature electrothermal film that can withstand temperatures up to 250°C for a long time, it is extremely advantageous to use PI as the base film in the process of patterning graphene by photolithography. Before patterning graphene by photolithography, graphene must first be prepared on the polyimide base film by:

1. Prepare a graphene film on a copper film or a nickel film by vapor deposition (CVD);

2. Immerse the copper film or nickel film with the graphene film in the acid solution, and remove the copper film or nickel film by soaking;

3. After the copper film or nickel film is completely corroded, only the graphene film is left floating on the surface of the acid solution, and the polyimide film is placed in the acid solution, so that the graphene film and the polyimide film interact with each other The force is naturally adsorbed together, and when picked up, the graphene film is adsorbed on the polyimide film.

After the graphene film adsorbed on the polyimide film is obtained, the graphene film is patterned by photolithography, so as to make driving electrodes and sensing electrodes and the like.

However, the adhesion of the PI base film is poor, and graphene is prone to fall off from the PI base film during the photolithographic patterning process, which seriously restricts the application of graphene in display devices.

Contents of the invention

The invention provides a graphene layer, a film material, a preparation method thereof and a flexible display device. The film material can tightly connect graphene and a polyimide substrate through an organic insulating film, thereby improving the performance of graphene and polyimide substrates. The adhesion between amines ensures that the graphene is not easy to fall off.

The invention provides a graphene layer, comprising a graphene film and an organic insulating film adhered to one side surface of the graphene film;

A hydrogen bond can be formed between the graphene film and the organic insulating film;

The organic insulating film is polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic resin.

The present invention provides a film material, comprising a polyimide substrate and the graphene layer described in the above technical solution, wherein the polyimide substrate is adhesively connected to the organic insulating film in the graphene layer.

The invention provides a kind of preparation method of membrane material, comprises the following steps:

(A) Graphene is deposited on a Cu film or a Ni film by vapor deposition, and modified to obtain a Graphene film with hydroxyl groups;

(B) coating a layer of organic insulating film on the graphene film with hydroxyl and curing;

(C) coating a polyimide film on the organic insulating film, and performing ultraviolet curing to obtain an intermediate;

(D) soaking the intermediate in an acid solution, removing the Cu film or Ni film to obtain a film material;

The organic insulating film is polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic resin.

Preferably, in the step (A), the modified method is:

Graphene is reacted with alcohols and chloroauric acid, and then subjected to electrodeposition to obtain a graphene film with hydroxyl groups.

Preferably, in the step (B), the pre-rotation speed of the coating is 300-500rpm/5-10sec, the main rotation speed is 600-1200rpm/15-30sec; the curing temperature is 200-250°C, the The curing time is 30-60 minutes.

Preferably, in the step (C), the pre-rotation speed of the coating is 300-500 rpm/5-10 sec, and the main rotation speed is 600-1200 rpm/15-30 sec.

Preferably, pre-drying is also included after coating, the pre-drying temperature is 90-120° C., and the pre-drying time is 120-150 seconds.

Preferably, in the step (C), the irradiation transmission speed of the ultraviolet curing is 0.8-1.6 m/min, and the irradiation time of the ultraviolet curing is 2-8 seconds.

Preferably, in the step (C), the drying temperature after the ultraviolet curing is 200-250° C., and the drying time is 30-60 minutes.

The present invention also provides a flexible display device, comprising the film material described in the above technical solution or the film material prepared by the method described in the above technical solution.

Compared with the prior art, the graphene layer of the present invention includes a graphene film and an organic insulating film adhered to one surface of the graphene film; hydrogen bonds can be formed between the graphene film and the organic insulating film; The organic insulating film is polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic resin. On the one hand, the organic insulating film can form hydrogen bonds with the graphene film in the subsequent photolithography process, and the connection is tight; on the other hand, the organic insulating film can also form a tight connection with the polyimide, so the organic insulating film effectively improves Adhesion properties of graphene to polyimide. The film material composed of graphene film, organic insulating film and polyimide substrate has good adhesion performance, and the graphene film is not easy to fall off.

Description of drawings

Fig. 1 is the structural representation of film material of the present invention;

Fig. 2 is the preparation flowchart of film material of the present invention;

Fig. 3 is a schematic diagram of the principle of forming a hydrogen bond between an acrylic resin and a graphene layer during photolithography.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

The embodiment of the present invention discloses a graphene layer, comprising a graphene film and an organic insulating film adhered to one surface of the graphene film;

A hydrogen bond can be formed between the graphene film and the organic insulating film;

The organic insulating film is polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic resin.

According to the present invention, the graphene layer includes a graphene film and an organic insulating film. The graphene film has a modification group that can form a hydrogen bond with the organic insulating film, and the modification group is preferably a hydroxyl group.

The preparation method of described graphene film is preferably:

Graphene is reacted with alcohols and chloroauric acid, and then subjected to electrodeposition to obtain a graphene film with hydroxyl groups.

In the preparation method of graphene, first, graphene, alcohols and chloroauric acid react to obtain graphene with carboxyl groups; the graphene with carboxyl groups undergoes electrodeposition to obtain graphene film with hydroxyl groups. For the conditions of the reaction, the existing conditions for graphene modification and doping can be used.

Through the above method, doping forms graphene with active functional groups, which on the one hand reduces the square resistance of graphene; on the other hand, forms active functional groups through doping, which is beneficial to react with its organic insulating film layer and improve adhesion.

The organic insulating film is polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic resin. The organic insulating film contains groups such as epoxy poly groups and double bonds, which can form hydrogen bonds with modification groups (such as hydroxyl groups) carried by the graphene film during subsequent photolithography. The hydrogen bond effectively improves the adhesion between the organic insulating film and the graphene film, and the two are closely combined.

The embodiment of the present invention discloses a membrane material, comprising a polyimide substrate and the graphene layer described in the above technical solution, the polyimide substrate is adhesively connected to the organic insulating film in the graphene layer.

In the present invention, the film material includes a polyimide substrate, an organic insulating film and a graphene film. The polyimide substrate is adhesively connected to the organic insulating film in the graphene layer, and the graphene film and the organic insulating film are adhesively connected, that is, the organic insulating film is located between the graphene film and the polyimide substrate . Since the organic insulating film has similar properties to polyimide, the organic insulating film has better connectivity with the polyimide substrate. Moreover, the organic insulating film can form hydrogen bonds with the graphene film in the subsequent photolithography process, and the hydrogen bond effectively improves the adhesion between the organic insulating film and the graphene film, and the two are closely combined. Combining the properties of the two aspects, the organic insulating film effectively improves the adhesion between graphene and polyimide, the film material of the present invention has better integrity, and the graphene is not easy to fall off during the subsequent photolithographic patterning process.

Fig. 1 is a schematic structural view of the film material of the present invention, in Fig. 1, 1 is a graphene film, 2 is an organic insulating film, and 3 is a polyimide substrate.

The embodiment of the present invention also discloses a method for preparing a membrane material, comprising the following steps:

(A) Graphene is deposited on a Cu film or a Ni film by vapor deposition, and modified to obtain a Graphene film with hydroxyl groups;

(B) coating a layer of organic insulating film on the graphene film with hydroxyl and curing;

(C) coating a polyimide film on the organic insulating film, and performing ultraviolet curing to obtain an intermediate;

(D) soaking the intermediate in an acid solution, removing the Cu film or Ni film to obtain a film material;

The organic insulating film is polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic resin.

According to the present invention, firstly, the graphene is deposited on the surface of the Cu film or the Ni film by vapor deposition method, and modified to obtain the graphene film with hydroxyl groups. The gas-phase deposition method is to use carbon-containing compounds such as methane as a carbon source, decompose at a high temperature, and grow graphene on the surface of a Cu film or a Ni film. For Ni and other metals with high carbon solubility. The carbon atoms produced by the cracking of the carbon source infiltrate at high temperature, and when the temperature drops, they are precipitated from the Ni film to nucleate and grow into graphene. For metals with low carbon solubility such as Cu, at high temperature, the gaseous carbon source is cracked to generate carbon atoms that are adsorbed on the surface, grow into graphene islands, and then grow and merge in two dimensions to obtain graphene. The carbon source can be hydrocarbons, such as methane, ethylene, acetylene and the like. For the temperature, pressure and reaction time used in the vapor phase deposition method, those skilled in the art can implement it according to known conditions.

The modified method is preferably:

The graphene is reacted with film alcohols and chloroauric acid, and then subjected to electrodeposition to obtain a graphene film with hydroxyl groups.

The reaction process is:

In the modified method, first, graphene, alcohols and chloroauric acid react to obtain graphene with carboxyl groups; the graphene with carboxyl groups undergoes electrodeposition to obtain graphene films with hydroxyl groups. For the conditions of the reaction, the existing conditions for graphene modification and doping can be used.

According to the present invention, after the graphene film with hydroxyl groups is obtained, an organic insulating film is coated on the graphene film with hydroxyl groups and cured. The organic insulating film is polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic resin. The coating is preferably performed by a gluing device of a photolithography machine. The coating process is as follows: spin-coat molten polyethylene, polyvinylidene fluoride, polytetrafluoroethylene or acrylic resin on the surface of the other side of the Cu film or Ni film through the gluing equipment of the photolithography machine superior. The pre-rotating speed of the coating is 300-500 rpm/5-10 sec, and the main rotating speed is 600-1200 rpm/15-30 sec. The curing temperature is preferably 200-250° C., and the curing time is preferably 30-60 minutes. Through curing, the hardness of the organic insulating film is increased and the transmittance of the organic insulating film is improved.

According to the present invention, after the organic insulating film is formed, a polyimide film is coated on the organic insulating film and cured by ultraviolet light to obtain an intermediate. The coating specifically includes: spin-coating the melted polyimide through the gluing equipment of the photolithography machine. During coating, the rotation speed of gluing is preferably 300-500 rpm/5-10 sec for the pre-rotation speed, and 600-1200 rpm/15-30 sec for the main rotation speed. The pre-rotation makes the resin spread evenly, and the main rotation makes the resin thin to the required thickness. After coating, the pre-drying temperature is preferably 90-120° C., and the pre-drying time is preferably 120-150 seconds. The radiation transmission speed of the ultraviolet curing is preferably 0.8-1.6 m/min. The irradiation time of the ultraviolet curing is preferably 2-8 seconds. The drying temperature after the ultraviolet curing is preferably 200-250° C., and the drying time is preferably 30-60 minutes.

According to the present invention, after the intermediate is obtained, the intermediate is soaked in an acid solution to remove the Cu film or Ni film to obtain a film material. The acid solution has a pH value of 1-3, preferably inorganic acids, and may be one or more of nitric acid, phosphoric acid and sulfuric acid. It can be understood that the acidic substances contained in the relevant acid liquid are not limited to the types listed above, and can also be other acidic substances known to those skilled in the art, and the types listed above are only the more commonly used and important ones. type. The soaking time is preferably 25-45 minutes, preferably 30-35 minutes, until the Cu film or Ni film is removed. soaked in acid. Not only can Cu film or Ni film be removed, but also the square resistance of graphene film can be reduced.

Fig. 2 is a flow chart of the preparation of the film material of the present invention. In Fig. 2, graphene is a graphene film, Cu is a copper film, OC is an organic insulating film, and PI is a polyimide substrate.

The present invention also provides a flexible display device, the film material described in the above technical solution or the film material prepared by the method described in the above technical solution.

The graphene layer of the present invention comprises a graphene film and an organic insulating film adhered to one side surface of the graphene film; hydrogen bonds can be formed between the graphene film and the organic insulating film; the organic insulating film is poly Vinyl, polyvinylidene fluoride, polytetrafluoroethylene, or acrylic type resins. On the one hand, the organic insulating film can form hydrogen bonds with the graphene film in the subsequent photolithography process, and the connection is tight; on the other hand, the organic insulating film can also form a tight connection with the polyimide, so the organic insulating film effectively improves Adhesion properties of graphene to polyimide. The film material composed of graphene film, organic insulating film and polyimide substrate has good adhesion performance, and the graphene film is not easy to fall off.

In order to further understand the present invention, the graphene layer, film layer, its preparation method and flexible display device provided by the present invention will be described in detail below in conjunction with the examples, and the protection scope of the present invention is not limited by the following examples.

Example 1

(A) Referring to the vapor phase deposition method described in the literature YuQK, JaureguiLA, WuW, et al. Control and characterization of individual grains and grain boundaries in graphene grown by chemical vapor deposition. Nat Mater, 2011, 10: 443-449, graphene is deposited on a Cu film or a Ni film.

Graphene, butanol and chloroauric acid were reacted at room temperature for more than 30 minutes in a phosphate buffer system with pH = 9, and a composite material was prepared by one-step electrodeposition by cyclic voltammetry under stirring conditions, and a composite material with hydroxyl groups was obtained. graphene membrane.

(B) Spin-coat the molten acrylic resin on the graphene film with hydroxyl by the gluing equipment of the photolithography machine, the pre-rotational speed (to make the resin evenly spread) 300rpm/10sec, the main rotational speed 600/15sec (to make the resin thinned to the desired thickness), cured at 200°C for 45 minutes.

(C) The melted polyimide is spin-coated by the gluing equipment of the photolithography machine, the pre-rotating speed of gluing is 500rpm/10sec, and the main rotating speed is 1200rpm/30sec. After coating, pre-dry at 100°C for 120 seconds. Then curing is carried out under the condition of ultraviolet light (i=365nm, g=408nm, h=436nm), the radiation transmission speed of ultraviolet curing is 1.2m/min, and the irradiation time of ultraviolet curing is 5 seconds. Finally, it was dried at 230° C. for 30 minutes to obtain an intermediate.

(D) soaking the intermediate in a mixed acid solution of nitric acid and phosphoric acid with a pH value of 2 for 30 minutes, removing the Cu film or Ni film to obtain a film material.

100 film materials prepared by the method described in Example 1 were patterned and developed by photolithography, and 95% of the film materials did not appear to fall off the graphene film.

The acrylic resin and the graphene layer form a hydrogen bond during the photolithography process, and the principle is shown in FIG. 3 . Fig. 3 is a schematic diagram of the principle of forming a hydrogen bond between an acrylic resin and a graphene layer during photolithography.

The existing method is used to prepare the graphene film with polyimide as the base, and the progressive photolithography method is patterned and developed, and more than 85% of the graphene falls off.

Example 2

(A) Referring to the vapor phase deposition method described in the literature YuQK, JaureguiLA, WuW, et al. Control and characterization of individual grains and grain boundaries in graphene grown by chemical vapor deposition. Nat Mater, 2011, 10: 443-449, graphene is deposited on the Cu film.

Graphene, butanol and chloroauric acid were reacted at room temperature for more than 30 minutes in a phosphate buffer system with pH = 9. Under stirring conditions, a composite material was prepared by one-step electrodeposition by cyclic voltammetry, and a carboxyl group was obtained. of graphene.

(B) The molten polyethylene is spin-coated on the graphene film with hydroxyl by the gluing equipment of the photolithography machine, and the gluing is transferred to Spincoatnig: pre-rotating speed (to spread the resin evenly) 500rpm/10sec, main rotating speed 1200rpm /30sec (thinning the resin to the desired thickness), curing at 230°C for 45 minutes.

(C) The melted polyimide is spin-coated by the gluing equipment of the photolithography machine, the pre-rotating speed of gluing is 400rpm/10sec, and the main rotating speed is 1100rpm/30sec. After coating, pre-dry at 120°C for 130 seconds. Then curing is carried out under the condition of ultraviolet light (i=365nm, g=408nm, h=436nm), the radiation transmission speed of ultraviolet curing is 1.6m/min, and the irradiation time of ultraviolet curing is 4 seconds. Finally, it was dried at 250° C. for 50 minutes to obtain an intermediate.

(D) soaking the intermediate in a mixed acid solution of nitric acid and phosphoric acid with a pH value of 1 for 25 minutes to remove the Cu film to obtain a film material.

100 film materials prepared by the method described in Example 1 were patterned and developed by photolithography, and 95% of the film materials did not appear to fall off the graphene film.

Example 3

(A) Referring to the vapor phase deposition method described in the literature YuQK, JaureguiLA, WuW, et al. Control and characterization of individual grains and grain boundaries in graphene grown by chemical vapor deposition. Nat Mater, 2011, 10: 443-449, graphene is deposited on the Cu film.

Graphene, amyl alcohol, and chloroauric acid were reacted at room temperature for more than 30 minutes in a phosphate buffer system with pH=9, and a composite material was prepared by one-step electrodeposition by cyclic voltammetry under stirring conditions, and a carboxyl group was obtained. of graphene.

(B) The polytetrafluoroethylene of melting is spin-coated on the graphene film with hydroxyl by the gluing equipment of the photolithography machine, and the gluing is transferred to Spincoatnig: pre-rotating speed (making the resin evenly spread) 500rpm/5sec, main Rotate at 1000rpm/15sec (thin the resin to the desired thickness), and cure at 230°C for 50 minutes.

(C) The melted polyimide is spin-coated by the gluing equipment of the photolithography machine, the pre-rotating speed of gluing is 450rpm/10sec, and the main rotating speed is 1000rpm/30sec. After coating, pre-dry at 120°C for 140 seconds. Then curing is carried out under the condition of ultraviolet light (i=365nm, g=408nm, h=436nm), the radiation transmission speed of ultraviolet curing is 1.6m/min, and the irradiation time of ultraviolet curing is 8 seconds. Finally, it was dried at 200° C. for 60 minutes to obtain an intermediate.

(D) soaking the intermediate in a mixed acid solution of nitric acid and phosphoric acid with a pH value of 3 for 30 minutes to remove the Cu film to obtain a film material.

100 film materials prepared by the method described in Example 3 were patterned and developed by photolithography, and 95% of the film materials did not appear to fall off the graphene film.

The existing method is used to prepare the graphene film with polyimide as the base, and the progressive photolithography method is patterned and developed, and more than 85% of the graphene falls off.

The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. a graphene layer, comprises graphene film and the organic insulating film adhering to described graphene film one side surface;

Hydrogen bond can be formed between described graphene film and organic insulating film;

Described organic insulating film is tygon, polyvinylidene fluoride, teflon or acrylic type resin.

2. a film material, comprises polyimide substrate and graphene layer according to claim 1, and described polyimide substrate adheres to the organic insulating film in described graphene layer and is connected.

3. a preparation method for film material, comprises the following steps:

(A) adopt vapour deposition process to be deposited on by Graphene on Cu film or Ni film, through modification, obtain the graphene film with hydroxyl;

(B) described with the graphene film of hydroxyl applying one deck organic insulating film and solidifying;

(C) coating polyimide film on described organic insulating film, and carry out ultra-violet curing, obtain intermediate;

(D) described intermediate is immersed in acid solution, removes Cu film or Ni film, obtain film material;

Described organic insulating film is tygon, polyvinylidene fluoride, teflon or acrylic type resin.

4. preparation method according to claim 3, is characterized in that, in described step (A), the method for described modification is:

Graphene and alcohols and gold chloride are reacted, then through electro-deposition, obtains the graphene film with hydroxyl.

5. preparation method according to claim 4, is characterized in that, in described step (B), the pre-rotating speed of described coating is 300 ~ 500rpm/5 ~ 10sec, and main rotating speed is 600 ~ 1200rpm/15 ~ 30sec; The temperature of described solidification is 200 ~ 250 DEG C, and the time of described solidification is 30 ~ 60 minutes.

6. the preparation method according to claim 3 ~ 5 any one, is characterized in that, in described step (C), the pre-rotating speed of described coating is 300 ~ 500rpm/5 ~ 10sec, and main rotating speed is 600 ~ 1200rpm/15 ~ 30sec.

7. preparation method according to claim 6, is characterized in that, in described step (C), also comprises predrying after described coating, and predrying temperature is 90 ~ 120 DEG C, and the pre-dried time is 120 ~ 150 seconds.

8. preparation method according to claim 7, is characterized in that, in described step (C), the irradiation transfer rate of described ultra-violet curing is 0.8 ~ 1.6m/min, and the irradiation time of described ultra-violet curing is 2 ~ 8 seconds.

9. the preparation method according to claim 7 ~ 8 any one, is characterized in that, in described step (C), the bake out temperature after described ultra-violet curing is 200 ~ 250 DEG C, and drying time is 30 ~ 60min.

10. a flexible display device, is characterized in that, comprises the film material that described in film material according to claim 2 or claim 3 ~ 9 any one prepared by method.