Let’s make future bright!!
Materials in the field “who shuffle?”
British researchers at the University of Manchester and Tim Andre cover Kesitiya · Nuowoxiefu first discovered, when the graphite layer is thin to only one carbon atom thick, its toughness and electrical properties are very prominent. The findings in the scientific community caused quite a stir, not only because it broke a two-dimensional crystal can not be real and theoretical predictions, more importantly, many properties of graphene could change our lives. Andre Farm and cover Kesitiya · Nuowoxiefu because of outstanding contributions in the field of graphene won the Nobel Prize.
“Indigenous methods” made out of new materials
Scientists recently announced a given user “super vision” of a contact lens manufacturing plans, from the University of Michigan research team, said graphene is embedded within the contact lens, excellent photographic capabilities, able to detect visible light and invisible light The infrared general, with night vision function. The news cast a magical aura graphene again.
The birth of the first sheet of graphene monolayer is not the number of “technical content.” Andre lid Farm with scotch tape on the graphite look, so there will be a graphite layer is adhered to the tape. The tape is then folded in half, stick a little longer opened, so that both ends of the tape has a graphite layer, graphite layer has thinned. So again when, on thin graphite tape to a thickness of only carbon atoms, a graphite layer becomes the graphene.
The scientists in the definition of graphene time somewhat embarrassed. Institute of Semiconductors, Chinese Academy of Sciences researcher told reporters Tan Pingheng graphene dissertations Professor Salim cover published in 2007, in the end of the two-dimensional crystal structure of how many layers of carbon atoms called graphene can be clearly defined: “single, double-layer, multi-layer (layer 3 to layer 10) Since the material remains two-dimensional crystal properties, can be called graphene. ”
China graphene industry technology innovation strategic alliance in 2013 on the definition given in the standard material graphene, graphene is considered the standard definition of the graphene, graphene and bilayer graphene layers less (3 layers to 10 layers) collectively. Tan Pingheng think, how to identify broad layers of graphene is graphene research and industrial development need to solve the problem.
Although the “name” is not positive, but countries have shown enough enthusiasm. January 2013, the EU will graphene as one of the “Future Emerging Technologies flagship projects,” 10-year plan to provide 1 billion euros funding; at the end of 2012 Britain announced that it would invest an additional 21.5 million pounds funding Graphene commercialization process, and to establish a national research institutions; the United States, South Korea and Japan respectively in graphene manufacturing computer chips and transistors in the field, a flexible touch screen and a flexible organic electroluminescent devices in the field, and the field of heat transparent conductive film film forefront of the world.
According to incomplete statistics, the current company to make the world scale graphene prepared more than 50, in which China had more than a dozen, many research results have been cutting-edge in the world.
Challenges various “impossible”
With its special physical structure and characteristics, graphene can bring disruptive change in many areas.
If it is successful or supercapacitor electrode material for lithium-ion batteries, apply the current popular words, “Mom no longer have to worry about my battery up.” According to the Shanxi Institute of Coal Chemistry, Dr. Cheng Chen Meng introduced, the storage material there are two key metrics, one conductivity, graphene is the world’s smallest resistivity material, the electron mobility in graphene free two-dimensional plane, the like the car drove on the highway is generally smooth; the second is the specific surface area, which directly affects the energy storage capacity than the material, which is the battery life. All components are graphene carbon atoms at the surface, the energy storage is valid, it is not wasted. “Only 5 minutes to complete a mobile phone charging, and can be used three days or even longer.” Cheng Chen Meng said that this application might be for the electric vehicle battery to open a new window in terms of energy saving and environmental protection is expected to exceed.
Mobile phones, computers and other electronic products with a long time may have a fever, this is because the heat generated by the operation can not be sustained and timely exchange with the outside through the heat sink. With high-power replacement of electronic products, increasing cooling requirements, and this is precisely graphene opportunity.
According to information Chen Cheng Meng provided theoretical thermal conductivity at room temperature graphene up to 5300 watts / meter-Kelvin, the US laboratory has detected a monolithic graphene thermal conductivity of more than 4000 watts / meter-Kelvin, which goes beyond the carbon nano tubes, highly oriented diamond and graphite, and much higher than the thermal conductivity of the best metal copper reached an order of magnitude. “But these properties are based on a very microscopic nanoscale, invisible, intangible, real practical applied more difficult.” Cheng Chen Meng said, according to the high thermal conductivity of graphene performance, they have successfully Institute and graphene carbon fiber composite to the new film, the thermal conductivity can be over 1100 watts / meter-Kelvin.
Graphene oxide graphene considered “close”, using thin film made from it have excellent performance. In 2012, Professor Wu Hengan Engineering Science Department of Modern Mechanics, University of Science and Technology of China and Professor Andre lid Farm group cooperation, the use of graphene oxide to produce a new type of gas barrier permeable film material. They made an interesting experiment, with this film sealed bottle of vodka, as a result of water evaporation, the taste of wine more concentrated. Wu Hengan said: “The specific interaction of water with the graphene surface, accelerating the water molecules through the nano-Road speed.”
In 2014, this collaborative research group further produce graphene oxide film having superior ion filtering capabilities. According to Wu Hengan introduced aquatic environment graphene oxide film under the action of water, the water can block radius greater than 0.45 nm ions or molecules. These findings are in desalination and purification, sensor technology, and energy conversion and other fields have broad application prospects.
Rookie carbon family too “noble”
Group C has many good genes graphene, but also to the market in time. Chen Cheng Meng told reporters that at present the vast majority of manufacturers still in graphene from the laboratory to the pilot, or pilot to the industrial transition phase.
“In fact, graphene industry, the core problem facing the downstream application is not open, unable graphene products, production processes are unable to shape and cure.” Cheng Chen Meng said. Current graphene “There is no market price”, the price is too high. According to different tastes, graphene price of 1,000 yuan per gram to 8,000 yuan price range, high prices suppressed demand, demand is limited to existing research institutions, research institutes.
Prepared immature technology also hindered the large-scale application of graphene. Cheng Chen Meng introduced, prepared graphene more mature way of physical and chemical methods, a typical representative of which physical law taped way from the graphite crystal obtained, this method can get the structure of perfect graphene crystal, more suitable for the development of electronic devices or physics, but not mass production.
Production is mainly dependent on chemical An academic is called “bottom-up” approach, that is, small molecules or carbon atoms by chemical vapor deposition, epitaxial growth or the way organic synthesis assembled into graphene sheets. This method is relatively easy to expand the size of some of the resulting graphene crystal structure is relatively complete, more suitable to do the transparent conductive film solar cell or a touch screen. Another way is the “top-down” approach, sometimes called chemical lift-off method, is three-dimensional graphite crystal layers to dismantle, peel into a single layer or a few layers of graphene products.
“The manufacturers of process routes used intercalation agent and there is a difference. Some salt intercalation liquid then peeled, graphene prepared in this way a low oxygen content, good conductivity, but relatively low degree of peeling point, large surface area less than, more suitable for making a conductive agent; some first oxide intercalation then peeled, this method is the high degree of delamination, surface area, but to make graphene more defects, quantity of oxygen, a surfactant, strong, more suitable to do catalysis, energy storage and other applications. “Cheng Chen Meng said. Graphene materials for advanced technology development, equipment manufacturing and process control is still a major issue.
From the current perspective of the development of technology, most likely to achieve industrialization and the use of graphene downstream industry is the field of composite materials technology and display. Adding graphene to plastic (10895, 10.00, 0.09%), rubber (15325, -390.00, -2.48%), paint and other matrix, “tune out” the product in performance will be stronger. For vapor deposition method to graphene, Chen Cheng Meng believes its applications focused on touch screens and solar cells, and other fields.