KR20130076242A

KR20130076242A - Preparing graphene nano ribbon

Info

Publication number: KR20130076242A
Application number: KR1020110144755A
Authority: KR
Inventors: 김용중; 박세민; 이성영; 안정철; 김병주
Original assignee: 재단법인 포항산업과학연구원
Priority date: 2011-12-28
Filing date: 2011-12-28
Publication date: 2013-07-08

Abstract

PURPOSE: A manufacturing method of graphene nanoribbon is provided to simply obtain graphene nanoribbon of nanosizes based on thermal shock without a separate oxidization or reduction process. CONSTITUTION: A manufacturing method of graphene nanoribbon includes the steps of: immerging carbon nanotubes in an ultra-low temperature tub (S110); and injecting the immersed carbon nanotubes in liquid water, and applying thermal shock to the carbon nanotubes (S120). The ultra-low temperature tube is formed by liquid nitrogen or liquid argon. [Reference numerals] (S100) Carbon nanotube; (S110) Immerse in an ultra-low temperature tub; (S120) Inject in room temperature or warm water; (S130) Filter; (S140) Dry; (S150) Graphene

Description

Preparation method of graphene nanoribbons {PREPARING GRAPHENE NANO RIBBON}

The present invention relates to a method for producing graphene nanoribbons, and more particularly, to a method for producing graphene nanoribbons having a large ratio of width and length by applying thermal shock to carbon nanotubes.

Generally, graphene is a two-dimensional thin film of honeycomb structure made of a layer of carbon atoms. Various methods are currently known for producing graphene sheets, including peeling off the adhesive tape of an individual graphene layer from graphite, chemical peeling of the graphene layer from graphite, and chemical vapor deposition processes, each method being approximately picograms. Provide graphene. Lithography and synthesis procedures have been developed to produce trace amounts of graphene nanoribbons.

In addition, the graphene nanoribbons were produced by partially encapsulating the carbon nanotubes in the polymer and then performing plasma etching to cut the carbon nanotubes in the longitudinal direction. Further, by peeling by interaction and reaction with lithium in a liquid ammonia solvent, non-selective longitudinally open multilayer graphite structures, such as partially open multi-walled carbon nanotubes (MWNT), Graphene flakes and hydrogen terminated graphene nanoribbons were produced. The chemical vapor deposition process has produced visible graphene nanoribbons.

In addition, there is a problem in economics and usability by heat treatment at a high temperature of more than 900 ℃ when manufacturing graphene.

For example, Zhong-Shuai Wu et al. Produced graphene by producing graphite oxide by Hummers and Offeman method, and then heat-treating at 2000 ° C. for 20 seconds in a hydrogen atmosphere using a hydrogen arc discharge method. , Michael J. MaAllister et al., Prepared graphite oxide by Staudenmaier method and heat-treated at 1050 ℃ for 30 seconds in an argon atmosphere oven, Xiaolin Li et al. Produced graphite oxide by Hummers and Offeman method After the heat treatment at 1000 ℃ 60 seconds to prepare the graphene.

In the graphene manufacturing process, chemicals such as strong acids and salts that cause environmental problems are used. In particular, when the salt is added, there is also a risk of explosion due to a gas generated by a rapid reaction. In order to remove acid and salt, many waste waters are generated to generate environmental problems. In the stripping process, high temperature or chemical reducing agent of 1000 ° C. or higher causes energy problems and environmental problems. Best of all, the lab-based process took a long time, one to two weeks, which drastically reduced productivity for mass production.

Embodiments of the present invention to provide a method for producing a graphene nanoribbon simply by applying a thermal shock using a single layer carbon nanotubes and a thin multilayer carbon nanotubes as starting materials.

In one or more embodiments of the present invention, the carbon nanotubes are immersed in a cryogenic bath; Injecting the immersed carbon nanotubes into liquid water to apply thermal shock to the carbon nanotubes; Graphene nanoribbon manufacturing method comprising a may be provided.

Carbon nanotubes of one or more embodiments of the present invention are characterized in that they are single-walled carbon nanotubes or multi-walled carbon nanotubes of 20 nm or less.

In one or more embodiments of the present invention, the cryogenic bath is formed by liquid nitrogen or liquid argon, and may further comprise the step of removing moisture by filtering the carbon nanotubes subjected to the thermal shock. After the filtering step may further comprise the step of drying.

Embodiments of the present invention can be prepared by the graphene nanoribbons of nano (nm) size by simply applying a thermal shock without a separate oxidation process or reduction process.

1 is a process flowchart of manufacturing a graphene nanoribbon according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention, and are not intended to limit the scope of the inventions. I will do it.

In general, a graphene manufacturing method on a plate (flake) is prepared by producing graphite oxide by reacting graphite with a strong acid and a salt, and then preparing the graphene through the reduction process. Graphite is a structure in which two-dimensional graphene sheets of plate shape in which carbon atoms are connected in a hexagonal shape are stacked. In addition, the graphite oxide is a reaction product obtained by reacting graphite in a mixed solution of an oxidizing agent and a strong acid for a long time, and is layered graphite having a layered structure formed by oxygen invading and bonding between carbon network planes. In the dried state, the interplanar distance of the graphite oxide is about 0.6 nm or more. At this time, the shape of the obtained graphene is irregular and difficult to classify the width and length without having a uniform shape.

In the embodiment according to the present invention, without using a strong acid, such as the Hummer's method or the Steudenmeir method, which is used in the conventional graphene flake manufacturing, a high temperature heat treatment process for peeling is unnecessary. Do.

To this end, according to the embodiment of the present invention, carbon nanotubes having a large curvature, that is, single-walled carbon nanotubes or thin multi-walled carbon nanotubes as starting materials (S100) After briefly immersing in a cryogenic temperature atmosphere such as liquid nitrogen and liquid argon (S110), and then rapidly added (S120) to room temperature water, that is, water of about 30 ℃ by applying a rapid temperature change to thermal shock to the carbon nanotubes Graphene nanoribbons are prepared by the addition. The tube structure of the carbon nanotubes is broken by the thermal shock and the tube structure of the broken carbon nanotubes is obtained by ribbon graphene. That is, in the prior art, the carbon nanotubes were separated by an oxidation process and a high temperature process, but in the embodiment of the present invention, graphene nanoribbons can be obtained by breaking the tubes of the carbon nanotubes by thermal shock.

The reason why the graphene nanoribbons can be manufactured by applying thermal shock as described above can be easily understood by looking at the structure of graphene. Graphene is a two-dimensional thin film of honeycomb structure made of a layer of carbon atoms. The carbon atom has a carbon hexagonal network that is unfolded in two dimensions by sp ² hybrid orbits. Graphene's hexagonal network structure is 0.3nm thick, with only one carbon atom.

Graphene nanoribbons are a special class of graphene that similarly features a two-dimensional base plane but has a high aspect ratio of its length to its width. The graphene nanoribbons are similar to carbon nanotubes having a large aspect ratio defined by one or more layers of graphene sheets that are dried to form a cylinder.

In the embodiment according to the present invention, but as a starting material for the production of graphene mainly use low-cost thin multilayer carbon nanotubes, single layer carbon nanotubes and of course multilayer carbon nanotubes of 20nm or less can be applied to the embodiment according to the present invention. have. In the case of multilayer carbon nanotubes larger than 20 nm, a large amount of graphene nanoribbons are not easily obtained even when thermal shock is applied, and thus, in embodiments according to the present invention, multilayer carbon nanotubes of 20 nm or less are used.

By the above process, ribbon-like graphene having a large aspect ratio is obtained, and a large number of amorphous flakes that are irregularly separated during peeling are included.

Therefore, the graphene nanoribbons in a state of water is filtered using a centrifugal rotor or the like by a mechanical method (S130). The filtering removes moisture.

Thereafter, the graphene nanoribbons in which the moisture is removed is heated and dried (S140) to produce usable graphene (S150).

In the embodiment according to the present invention, the cryogenic bath is made of liquid nitrogen or liquid argon. The temperature at this time is about -179 ° C for liquid nitrogen and about -189 ° C for liquid argon. Liquid helium may also be used, but care must be taken because of the potential for explosion.

In addition, in the embodiment according to the present invention, carbon nanotubes are immersed in a cryogenic bath and then introduced at room temperature. The cryogenic temperature in the embodiment according to the present invention means a case where nitrogen or argon is in a liquid phase, so that carbon carbon nano is sufficiently at room temperature. The thermal shock may be applied to the tube, and in addition, if the thermal shock may be applied to the carbon nanotubes, even when introduced into water having a temperature higher than room temperature, the temperature may be added at a temperature of 100 ° C. or lower. That is, the temperature of the water for applying the thermal shock in the embodiment according to the present invention is 0 ~ 100 ℃ is enough water in the liquid state, but it is advantageous in terms of energy saving to put at room temperature.

In addition, it is not necessary to limit to liquid nitrogen or liquid argon as a means for the cryogenic bath, and a temperature low enough to make a temperature difference for applying a thermal shock. For example, when carbon nanotubes are immersed in a low temperature bath at −100 ° C. and then introduced into 90 ° C. water, thermal shock may be sufficiently applied to the carbon nanotubes.

As described above, in the embodiment according to the present invention, graphene nanoribbons may be simply manufactured by preparing graphene nanoribbons by a simple thermal shock without undergoing a strong acid and a high temperature process.

Graphene nanoribbons prepared by the method have a number of useful properties, including advantageous electrical properties. Unlike carbon nanotubes that are metallic, semimetallic or semiconducting depending on chiral conformation and diameter, the electrical properties of graphene nanoribbons are determined by their width and their edge configuration and functionality. For example, graphene nanoribbons less than about 10 nm wide are semiconductors, while graphene nanoribbons greater than about 10 nm wide are metallic or semimetallic conductors. And, edge conformation of graphene nanoribbons having an "armchair" or "zigzag" arrangement of carbon atoms with terminal edge functionality affects the transport of electron carriers. The "armchair" and "zigzag" arrangements above are similar to those defined in carbon nanotube technology. In addition to the electrical properties described above, graphene nanoribbons have excellent mechanical properties with carbon nanotubes and graphene sheets.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

Claims

Immersing the carbon nanotubes in the cryogenic bath;
Injecting the immersed carbon nanotubes into liquid water to apply thermal shock to the carbon nanotubes;
Graphene nanoribbon manufacturing method comprising a.

The method of claim 1,
The carbon nanotubes are graphene nanoribbons, characterized in that the single-walled carbon nanotubes (single-walled carbon nanotube) or 20-nm or less multi-walled carbon nanotubes (multi-walled carbon nanotube).

The method of claim 1,
The cryogenic bath is graphene nanoribbon manufacturing method characterized in that formed by liquid nitrogen or liquid argon.

The method of claim 1,
Graphene nanoribbons manufacturing method further comprising the step of removing the water by filtering the carbon nanotubes subjected to the thermal shock.

5. The method of claim 4,
Graphene nanoribbons manufacturing method characterized in that it further comprises the step of drying after the filtering step.