Three months ago, we published the report Graphene: Material That Will Change Our World. Since readers of our blog have expressed so much interest in the subject, and given that there have been continuous developments related with this revolutionary material over this period, we now offer a second part in order to provide further information about some of its applications and to summarise the greater part of the most interesting news.
Video Grafeno, características y aplicaciones (Graphene: Characteristics and Applications – Tecnonauta). In Spanish.
Video in English.
The Discovery of Graphene Aerogel, the Lightest Material in the World
A team of researchers from Zhejiang University (China), led by Professor Gao Chao, has created the lightest material ever known (with a density of only 0.16 mg/cm3). This ultra-light gel is made from dry-frozen carbon nanotubes and layers of graphene oxide, from which the oxygen is extracted. The possible applications of this material range from energy storage and its use in microelectronics through to the benefits of its extraordinary powers of absorption, for example in cases of oil spills in the sea.
Professor Gao Chao talks about his discovery in this video (in English).
Desalinisation of Water
Scientists are studying how graphene may be used in water desalinisation processes, for example in removing the salt from seawater and brackish waters in order to make them potable or useful for other purposes.
For example, the company Lockheed Martin, traditionally known for its production of military systems and aircraft has devised a process for perforating graphene (and, as we previously noted, graphene sheets are only one atom thick) in such a way that the holes are large enough to filter the water and small enough to block salt molecules. By comparison with traditional methods, the advantage of this molecular filtration system is that the graphene membrane is extremely thin, and the thinner the filtering material, the less energy required to permit this process of reverse osmosis (see press release, in English).
Video of the Massachusetts Institute of Technology (MIT).
Graphene Modified Textiles
Another of the remarkable properties of graphene is its impermeability. Researchers around the world are working on the different applications suggested by this attribute, for example water resistant clothing.
Professor Francisco Cases of the Technical University of Valencia (UPV) explains the applications of graphene in the textile industry.
A New Property of Graphene Discovered: Total Light Absorption
Spanish researchers at the Instituto de Química-Física Rocasolano (Rocasolano Institute of Physical Chemistry) in Madrid and the Instituto de Ciencias Fotónicas (ICFO – Institute of Photonic Sciences) in Barcelona have discovered that a sheet of graphene, which is only one atom thick, is capable of 100% light absorption, including light in different colours. This new property joins others that are already known, including the fact that graphene makes it possible to develop infrared photosensors, biosensors, cameras, solar panels, and other applications. This work with graphene has been described in the journal Physical Review Letters and has given rise to applications such as the two described below.
Cheaper, Highly Sensitive Graphene Sensors Eliminate Need for the Camera Flash
At present, compact cameras include a CMOS sensor, which does not produce detailed images in conditions of poor light. Only DSLR cameras are able to produce high-quality photographs in these conditions and they are expensive.
A team of researchers at the Nanyang Technological University (Singapore), led by Professor Wang Qijie, has created an image sensor made of pure graphene, which will soon make it possible to produce clear, detailed photographs taken in the dark without any need to use a flash.
The new sensor is extremely sensitive to both visible and infrared light, which is to say, approximately 1,000 times more sensitive than any other sensor used in cameras today. In other words, it is able to assimilate 1,000 times more light than the sensors presently incorporated in digital cameras. Quite apart from comparisons with conventional cameras, the applications of this graphene sensor include satellite imaging, mid-infrared uses, and other possibilities in the communication industries.
The industry will only need to replace the sensors in current use by graphene sensors, a minor adjustment in the manufacturing process, which will remain otherwise unchanged. The research team say that the graphene sensors will lower the final price of cameras which, moreover, consume ten times less energy.
Ultrashort Laser Pulses over the Entire Spectrum of Visible Light
Experiments suggest that, owing to its ability to absorb light over a broad range of wavelengths, graphene can be used to create ultrashort laser pulses which are released in a fraction of a nanosecond. This follows the work in 2009 of the physicist Andrea Ferrari of the University of Cambridge who showed that graphene can absorb light in the infrared spectrum. The latest advance will make it possible to produce smaller and more economical lasers with applications from micro-machinery through to medicine (see the article in Nature).
Technology for Low-Cost Extraction of Graphene from Coke Has Now Been Patented
As described in our first report, graphene is obtained from natural graphite which is extracted from coal mines. Although this material is plentiful in nature, the process of graphene extraction, which is carried out at high temperatures, entails considerable costs in terms of energy consumption. Recently, however, a group of Spanish researchers at the Instituto Nacional del Carbón (INCAR-CSIC – National Coal Institute of the Spanish Council for Scientific Research) has managed to extract graphene from coke, a product derived from coal and petroleum. The new technology, which has already been patented, considerably reduces the costs of producing graphene from graphite. This Spanish patent situates Spain in an excellent position in the research race which is currently taking place on a worldwide scale.
The research team led by Dr. Rosa Menéndez, head of the INCAR-CSIC Composite Materials Group and the CSIC coordinator in Asturias, will be taking part in the European Coalphenes project – funded by the European Commission – which will begin a three-year study in September with the aim of discovering how to extract graphene composites from coal derivates for applications requiring materials with a high capacity for heat dissipation.(enlace al INCAR en inglés para Juan. http://www.incar.csic.es/composite).
Grafeno. La vida dentro de 50 años (Graphene: Life within 50 Years, Neurosol).
Spain at the Forefront of Graphene Research
As both our reports show, Spain is an active participant in theoretical and applied graphene research. Several universities and companies are working in cutting-edge European projects and becoming points of reference in this new sector.
In our region, the Technical University of Cartagena has signed an agreement whereby it will be working with the Yecla-based company Graphenano in developing industrial applications. The company will supply the university with graphene in different physical forms and carbon nanofibres in order to assist the university researchers in their work.
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