Graphene, also known as single-layer ink, is a new type of two-dimensional nanomaterials, the hardest and most resilient nanomaterials found so far. Due to its special nano-structure and excellent physical and chemical properties, graphene is widely used in electronics, optics, magnetism, biomedicine, catalysis, energy storage and sensors. It is recognized as the "future material" and "revolutionary material" in the 21st century. Graphene-related patents have exploded (353 in 2010 and 1829 in 2012). In general, graphene technology began to enter the rapid growth stage, and quickly moved into the mature stage. The global graphene technology development and distribution competition is increasingly fierce, and the technical advantages of various countries are gradually formed.
Graphene was present in the laboratory in 2004, when two scientists from the university of Manchester, in the United Kingdom, Andre. Jem and kostya; Novoselov found that they could get thinner and thinner sheets of graphite in a very simple way. They strip the sheet of graphite out of the graphite, and then glue the two sides of the sheet to a special piece of tape. And so they keep doing this, and so the flakes get thinner and thinner, and they end up with a sheet of just one layer of carbon atoms, which is graphene. Since then, new methods have been developed to prepare graphene. After five years of development, it has been found that it is not far away to bring graphene into the field of industrial production. So they won the Nobel Prize in physics in 2010.
Chinese academy of sciences recently published a report pointed out that increasing graphene research and industrialization development, from the point of graphene patent field distribution, its layout application technology research hot spots include: graphene as lithium ion battery electrode materials, solar battery electrode materials, preparation of thin film transistor, sensor, semiconductor devices, composite material preparation, transparent touch screen, transparent electrode, etc. Mainly focused on the following four areas:
(1) sensor field
Graphene has been widely used in sensors because of its unique two-dimensional structure. It has the characteristics of small volume, large surface area, high sensitivity, fast response time, fast electron transfer, easy to fix proteins and keep them active, etc., which can improve the performance of sensors. Mainly used in the production of gas, biomolecular, enzyme and DNA electrochemical sensors. Nanyang technological university in Singapore has developed graphene optical sensors that are 1,000 times more sensitive than normal sensors. The rensselaer institute of technology has developed a cheap graphene sponge sensor that performs well beyond existing commercial gas sensors.
(2) energy storage and new display areas
Graphene has excellent conductivity and light transmittance. As a transparent conductive electrode material, it has good applications in touch screen, liquid crystal display and energy storage battery. Graphene is considered to be the most promising material to replace indium tin oxide in the production of touch screens. Leading companies such as samsung, SONY, sinovel, 3M, dongli and Toshiba have all made key r&d arrangements in this field. Researchers at the university of Texas at Austin used KOH to chemically modify graphene to form a porous structure, and the resulting supercapacitors had energy storage densities close to those of lead-acid batteries. Scientists at Michigan state university of technology have developed a unique honeycomb-like three-dimensional graphene electrode with a 7.8 percent photoelectric conversion efficiency and a low price that could replace platinum in solar cells. Toshiba has developed graphene and silver nanowire composite transparent electrode, and achieved large scale.
(3) semiconductor materials.
Graphene is considered to be an ideal material to replace silicon. A large number of powerful enterprises have developed graphene semiconductor devices. Sungkyunkwan university in South Korea has developed highly stable n-graphene semiconductors that can be used in the air for long periods of time. The graphene-silicon photoelectric hybrid chip developed by Columbia University has wide application prospects in optical interconnection and low power photonic integrated circuits. IBM researchers have developed graphene field-effect transistors with a period cutoff frequency of up to 100GHz and a frequency performance well above that of the most advanced silicon transistors of the same grid length (40GHz)
The field of biology.
Graphene and its derivatives are widely used in nano-drug transportation system, biological detection, biological imaging, tumor treatment and other aspects. Graphene-based biological devices or biosensors can be used for bacterial analysis, DNA and protein detection. For example, a graphene nanopore device developed by the university of Pennsylvania in the United States can quickly complete DNA sequencing. When graphene quantum dots are used in biological imaging, they have more stable fluorescence, less bleaching and less photodecay than fluorosomes. Although the application of graphene in biomedical field is at the initial stage, it is one of the most promising application fields in industrialization.