What is graphene? Graphene (graphene), also known as Single-layer Ink, is a new two-dimensional nanometer material, is the highest hardness and toughness of nano-materials found at present. Due to its special nanostructures and excellent physical and chemical properties, graphene is widely used in the fields of electronics, optics, magnetism, biomedicine, catalysis, energy storage and sensors, and is recognized as the "future materials" and "revolutionary materials" in the 21st century. Graphene-related patents began to show explosive growth (2010 353, 2012 up to 1829). Generally speaking, graphene technology began to enter the rapid growth period, and quickly to the technical maturity span.
Global graphene technology research and development layout competition is increasingly fierce, the technical advantages of various countries are gradually formed. Graphene appeared in the laboratory in 2004, when two scientists at Manchester University in England, Andre ˙ Jem and Kostya ˙ Nouvo, discovered that they could get thinner graphite flakes in a very simple way. They peel out the graphite sheet from the graphite and then glue the two sides of the sheet to a special tape, ripping the tape and splitting the graphite into pieces. Keep doing this, and the flakes get thinner, and finally, they have a thin sheet of carbon atoms, which is graphene. Since then, new methods of preparing graphene are emerging, and after more than 5 years of development, it has been found that it is not far away to bring graphene into the field of industrialized production.
As a result, the two men won the Nobel Prize for Physics in 2010.
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Second, the application of graphene field? According to a recent report published by the Chinese Academy of Sciences, Graphene research and industrial development continue to warm up, from the Graphene patent field distribution, its application technology research layout hotspots include: Graphene used as lithium-ion battery electrode materials, solar cell electrode materials, film transistor preparation, sensors, semiconductor devices, composite materials preparation, Transparent display of touch screen, transparent electrode, etc.
The main focus is on the following four areas: (i) Sensor area. Graphene because of its unique two-dimensional structure in the sensor has a wide range of applications, with small size, large surface area, high sensitivity, fast response time, fast electronic transmission, easy to fix protein and maintain its activity, can enhance the performance of the sensor. It is mainly used in the production of gas, biological small molecule, enzyme and DNA electrochemical sensor.
Nanyang Technological University in Singapore has developed a graphene optical sensor 1000 times times the size of a normal sensor; The Rensselaer Institute of Technology has developed a cheap graphene sponge sensor that performs far more than existing commercial gas sensors. (ii) Energy storage and new display areas. Graphene has excellent conductivity and light transmittance, as a transparent conductive electrode material, in touch screen, liquid crystal display, storage battery, etc. have good applications. Graphene is considered to be the most potential substitute for indium tin in touch screen manufacturing, and leading enterprises such as Samsung, Sony, FAI, 3M, Toray and Toshiba have made a key research and development layout in this field. The researchers at the University of Texas at Austin used Koh to chemically modify the graphene to form a porous structure, and the resulting super capacitance was close to the lead-acid battery. Michigan University of Technology scientists developed a unique honeycomb-like structure of three-dimensional graphene electrodes, photoelectric conversion efficiency of 7.8%, and low price, is expected to replace the platinum in the solar cell applications.
Toshiba developed a composite transparent electrode made of graphene and silver nanowires, and achieved large area. (iii) Semiconductor material field. Graphene is considered to be an ideal substitute for silicon, and a large number of powerful enterprises have developed graphene semiconductor devices. Han University has developed high stability N-type graphene semiconductors that can be exposed to air for long periods of time. A graphene-silicon photovoltaic hybrid chip has been developed at Columbia University in the United States, which has a wide application prospect in optical interconnection and low power photonic integrated circuits.
IBM researchers have developed graphene field-effect transistors with a cut-off frequency of up to 100GHz, which is much more than the cutoff frequency of the most advanced silicon transistors of the same gate length (40GHz). (iv) the biomedical field. Graphene and its derivatives are widely used in nano-drug transportation system, biological detection, biological imaging and tumor therapy. Graphene as a grass-roots biological device or biosensor can be used for bacterial analysis, DNA and protein detection. A graphene nano-pore device developed at the University of Pennsylvania can quickly complete DNA sequencing. Graphene quantum dots are used in biological imaging, which is more stable than fluorescence, and does not appear light bleaching and light decay.
The application of graphene in the biomedical field is in the initial stage, but it is one of the most promising applications in the field of industrialization.