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Therefore, it is expected that the graphene film can be used as a transparent conductive film such as a touch panel, an electronic paper, an organic EL panel, or a solar cell.
毎minute filming dozens of cm
In April 2012, the Japan Industrial Technology Research Institute (Industrial Research Institute) announced the development of a technology that can produce large-area graphene. This is a technique for high-speed film formation of graphene in a roll-to-roll (R2R) manner on a flexible substrate (Fig. 1). The winding speed of the rolls reached 30 cm in the film width, and the enthalpy reached tens of centimeters.
The production comprehensive research was carried out by a combination of the "Surface Wave Plasma Chemical Vapor Deposition (SWP-CVD)" method and R2R developed for the purpose of producing artificial diamond. The most common reason why a graphene film can be formed at a high speed is to maintain the temperature on the substrate at 300 ° C or higher and store it at a low temperature by CVD. The time required for film formation is only "30 seconds or less" (Nagawa Yako, Research Group of Nanomaterial Coatings Research Group, Research Institute for Nanotube Applications). It took exactly one hour or so to keep the temperature on the substrate at 1000 °C. 
Suitable for transparent conductive film
As a transparent conductive film used for various purposes, graphene has excellent characteristics. For example, the light transmittance is high. The light transmittance of single-layer graphene is theoretically 97.5%. Since the transmittance is not wavelength-dependent, graphene has high transmittance for electromagnetic waves in the near-infrared region which are very important for solar cells. Moreover, the durability against mechanical bending is also high. Graphene is very thin and there is almost no light storage problem with other films.
In addition, the gas barrier (Gas Barrier) property of graphene to water vapor is theoretically 10 to 11 g/m 2 /day, which can satisfy 10-6 g/m 2 /day required for organic EL panel packaging.
Regarding the sheet resistance value of the graphene film, "when the light transmittance of the product we produced was 87%, the sheet resistance value was 500 Ω / □" (Hitaguchi of the Research Institute), although it is slightly larger, "previous The sheet resistance is about 1 kΩ/□. It is planned to further reduce the resistance value in the future†(Nagagawa). A solution using a combination of a highly conductive metal nano mesh (Mesh Sheet) or the like is being considered.
The Research Institute has used the graphene produced by this technology to produce a touch panel and other products. “No problems can be found and it can work normally†(Production Research).
A problem other than the sheet resistance value includes a copper (Cu) foil in which graphene is formed, and it is required to have high quality and flatness, and it takes a certain time to transfer graphene from a copper foil to a PET film or the like. Hasegawa said, "The copper foil needs to be annealed (heated) for about one hour before the graphene film is formed to improve the flatness. The transfer requires the film to be melted after the film is pasted on the copper foil, so it takes time." .
Korean companies start selling manufacturing equipment
In the field of research and development of graphene, companies and research institutions in various countries are highly competitive. Among them, Korean companies are leading the world.
Although Korea's Graphene Square is a venture company that was established in January 2012, it has developed a large-area graphene film manufacturing facility that has been sold in Japan and other countries since the spring of 2012 (Fig. 2) Note 1). Japan’s general agent Itrix, the representative of the agency, Masaru Hasegawa, said, “I heard that the device has sold 100 units in Koreaâ€. 
Note 1) Graphene Square is a company founded by graphene researchers and Byung Hee Hong, a professor at Seoul National University in Korea. Most of the technicians come from South Korea's Samsung Techwin, which has been working on the development of graphene film-forming technology. However, Graphene Square has no capital relationship with the Samsung Group. 
The graphene film produced by this device is characterized by "the film resistance value is only 125 Ω / □, so the quality is high" (Hiragawa of the Research Institute) (Table 1). However, the product has a problem that the film formation temperature is as high as 1000 ° C and film formation takes time.
Graphene fabrication technology continues to emerge as a powerful candidate for transparent conductive films
Abstract In the large area of ​​tens of cm square or tens of cm square, the technology for mass production of carbon atom sheet-like materials - graphene is constantly unveiled. Therefore, it is expected that a graphene film can be used as a transparent conductive film of a touch panel, an electronic paper, an organic EL panel, and a solar cell.
In a large area of ​​tens of cm square or tens of cm square, the technology for mass production of carbon atom sheet-like materials - graphene is constantly unveiled. Figure 1: A 30 cm wide graphene film can be mass produced
(a) is an outline of a SWP-CVD apparatus for mass production of graphene films developed by ITRI. A cylindrical quartz tube in which an antenna is inserted is arranged, and an AC voltage of 2.45 GHz is applied thereto, thereby generating plasma. (b) is the "graphene touch panel" exhibited by the Research Institute in February 2012.
Figure 2: Korean manufacturer mass production manufacturing equipment
(a) is a CVD apparatus for producing an A4-size graphene film which is being sold by Graphene Square. The copper foil was first wound into a roll and placed in a quartz tube, and then methane (CH4) gas was injected thereinto, and heated to 1000 ° C, thereby forming graphene into a film. (b) A 30 inch (700 mm x 400 mm) graphene film produced in the same manner and transferred onto a PET substrate.