CAJ #13 - Last but not least

Graphene. It is an amazing material, one that will change the world and make us question everything we have known so far about science. Researchers around the globe are experimenting with graphene every day, always finding something new and exciting about it. Graphene opened up the doors for 2D materials, materials that up until now only excited in theory. The time of graphene and other 2D materials is yet to come and I hope that you are, as much as I am, anxious to see what it will bring us.

If you want to know more about graphene check out the following websites (I used them for my research too). Click on one of the following link and explore the world of graphene:

1) http://graphene-flagship.eu/

2) http://phys.org/news/2014-01-material-silicene-suicidal-tendencies.html#jCp

3) http://edition.cnn.com/2014/04/10/world/asia/graphene-samsung-breakthrough/ 

4) http://www.cnet.com/news/2014-budget-funds-graphene-research-and-an-alan-turing-institute/

5) http://www.bbc.com/news/science-environment-20846282

6) http://www.zdnet.com/graphene-gets-1bn-boost-as-eu-ploughs-funds-into-research-7000010419/

7) http://www.wired.co.uk/news/archive/2013-01/28/graphene-research-funding

8) http://www.sciencedaily.com/releases/2014/03/140309150546.htm 

9) http://www.extremetech.com/electronics/143907-cheap-graphene-based-solar-cells

10) http://www.businessinsider.com/graphene-for-smartphones-2014-4#ixzz32nytIq3g 

11) http://www.oled-info.com/samsung-youm

12) http://iopscience.iop.org/1367-2630/11/9/095002

13) http://arxiv.org/ftp/arxiv/papers/0906/0906.3799.pdf 

14) http://qz.com/135380/its-stronger-than-steel-and-paper-thin-but-graphene-isnt-living-up-to-its-promise/

15) http://www.aps.org/publications/apsnews/200910/physicshistory.cfm 

16) http://www.graphenea.com/pages/graphene-graphite#.U2P1N4F_t1Y

17) http://www.newscientist.com/special/instant-expert-graphene

18) http://www.graphene.manchester.ac.uk/story/

19) http://www.independent.co.uk/news/science/the-graphene-story-how-andrei-geim-and-kostya-novoselov-hit-on-a-scientific-breakthrough-that-changed-the-world-by-playing-with-sticky-tape-8539743.html

20) http://gizmodo.com/5988977/9-incredible-uses-for-graphene

21) http://www.graphenea.com/pages/graphene-uses-applications#.U2qyzYF_t1Y

22) http://www.businessgreen.com/bg/feature/2279993/how-graphene-breakthrough-is-revolutionising-green-technology#

23) http://guardianlv.com/2013/12/graphene-is-going-to-change-the-world/

24) http://www.telegraph.co.uk/finance/newsbysector/industry/10251209/Graphene-A-new-miracle-in-the-material-world.html

25) http://www.businessweek.com/articles/2013-08-20/scientists-take-graphene-to-the-next-level

26) http://www.popsci.com/science/article/2013-01/eu-invests-135-billion-developing-practical-applications-graphene

27) http://edition.cnn.com/2013/10/02/tech/innovation/graphene-quest-for-first-ever-2d-material/

28) http://www.ibtimes.com/what-graphene-5-incredible-facts-about-miracle-material-you-need-know-1399503

29) http://derstandard.at/1392687693653/Nach-Graphen-nun-Wolfram-mit-Selen-Neues-atomar-duennes-Supermaterial

30) http://www.telegraph.co.uk/sponsored/technology/cool-list/10336014/cool-tech-graphene.html

31) http://www.newelectronics.co.uk/electronics-news/new-super-material-set-to-rival-graphene/58169/

32) http://www.newelectronics.co.uk/electronics-news/new-super-material-set-to-rival-graphene/58169/

33) http://www.theguardian.com/science/2013/nov/26/graphene-molecule-potential-wonder-material

34) http://newsoffice.mit.edu/2012/hybrid-flexible-light-solar-cells-1221

35) http://www.businessgreen.com/bg/feature/2279993/how-graphene-breakthrough-is-revolutionising-green-technology#

36) http://www.extremetech.com/electronics/143907-cheap-graphene-based-solar-cells

37) http://www.eetimes.com/document.asp?doc_id=1320283

38) http://www.independent.co.uk/news/science/new-wonder-material-stanene-could-replace-graphene-with-100-electrical-conductivity-8967573.html

39) http://cleantechnica.com/2014/02/17/graphenes-great-water-filtration-potential-unveiled-new-research/

40) http://newsoffice.mit.edu/2012/graphene-water-desalination-0702

41) http://pubs.acs.org/doi/abs/10.1021/nl3012853

42) http://www.independent.co.uk/voices/comment/discovering-graphene-was-only-the-start--its-potential-is-almost-limitless-8952687.html?origin=internalSearch

43) http://www.bbc.com/news/uk-england-manchester-25016994

44) http://www.azom.com/article.aspx?ArticleID=10335

45) http://www.understandingnano.com/graphene-chemical-sensor.html

46) http://www.understandingnano.com/graphene-applications.html

And last but not least, a TED Talk about graphene science: https://www.youtube.com/watch?v=eh3dA8xnZ4Y

I truly hope that you had fun while reading my CAJ, that you learned something new and are as thrilled as I am about graphene and its impact on us and our future.

XOXO A.

CAJ #12 - Ultrafiltration membranes

 As already mentioned in one of my earlier posts, the potential uses of graphene seem endless. It is hard to say where it should be applied first. However, in my opinion, we should invest more in the research of ultrafiltration membranes based on graphene.

Graphene possesses a number of qualities with regard to its interactions with water. Previous research showed that thin membranes made from graphene oxide laminates were impermeable to gases and vapours, except for water. New research is now testing the effectiveness of these membranes with regard to water filtration. Graphene could be used as a ultrafiltration medium that would act as a barrier between two substances.

What sets graphene apart from other similar membranes is that it is only one atom thick. A team of researchers at Columbia University has created a monolayer graphene filter with pore sizes as small as 5nm (nanometer). In comparison, other nanoporous membranes have pore sizes of 30-40nm. The membrane's ability to prevent salt passage depends on pore diameter. If the pores are too big, ions will be able to flow through it. If the pores are small enough, water will flow through while blocking out the ions. Because the pores in monolayer graphene filters are so small they can effectively filter NaCl (sodium chloride) salt from water.

Graphene is stronger and less brittle than aluminium oxide (currently used in sub-100nm filtration applications). These new types of membranes could be used in water filtration and desalination systems, as well as efficient and economically more viable biofuel creation. This would be a huge break through, especially the desalination system because all the water on Earth would become drinkable. This would help solve the problem of water shortage for many African countries. 

XOXO A.

CAJ #11 - Other potential uses of graphene

1)      Sensors to diagnose diseases

Researchers have found out that graphene, strands of DNA and fluorescent molecules can be combined to diagnose diseases. The sensors are made by attaching fluorescent molecules to single strand DNA and then attaching the DNA to graphene. An identical single strand of DNA is combined with the strand on the graphene and a double strand DNA is formed. This double strand DNA floats off from the graphene and increases the fluorescence level. This process creates a sensor that can detect the same DNA for a particular disease in a sample.

2)      Bulletproof vests

Graphene could be applied in materials used in the production of bulletproof vests. Researchers from the University of Wollongong developed a new graphene-based material by combing equal parts of carbon nanotubes with graphene and adding them to the polymer. It has then been processed into fibers by using a wet-spinning method. This new material is stronger than spider silk and Kevlar that have so far been used to produce bulletproof vests. Bulletproof vests are made of layers of strong fibers that absorb the energy of the bullet, deform it, minimize the force of it and prevent the bullet from penetrating the vest. The research team working on this project said that the material is inexpensive and could be produced in large quantities.

3)      Gas sensors

The new gas sensors based on graphene could outperform today's leading gas sensors in detecting potentially dangerous and explosive chemicals, a study conducting at the Rensselaer Polytechnic Institute showed.  The sensors are made from continuous graphene nanosheets that grow into a foam-like structure about the size of a postage stamp. The flexible sensors measured ammonia and nitrogen dioxide at concentrations as small as 20 parts-per-million. This new discovery could be used by bomb squads, the police, various government agencies, as well as on airports.

4)      Condoms

Yes, you read right, I meant what I said. Graphene could be used in the production of condoms. Since graphene is highly stretchable, super thing, non-toxic and very strong it could be used to produce condoms that would not be able to be felt during intercourse. The idea is to mix graphene with latex in order to get a super thin and strong condom. These kinds of condoms would also act as an effective barrier to HIV and other sexually transmitted disease, more effective than condoms of this day and age can. This would be of great importance for the Third World where the birth rate is high and many people are infected by AIDS. One of the investors in condoms from graphene is the Bill and Melisa Gates Foundation that awarded scientists $100,000 for research.

XOXO A.

CAJ #10 - Who funds graphene research?

One of the biggest investors in graphene research is the European Union. Last year the European Commission invested €1bn to researchers to find a way to exploit graphene.

The funding will be distributed over a period of 10 years. It will go directly to the Graphene Flagship, led by Professor Jari Kinaret, from Sweden's Chalmers University in Gothenburg. The Graphene Flagship will co-ordinate 126 academic and industrial research groups across 17 countries. Their initial budget is €54m. The funding graphene received is part of Europe's Future and Emerging Technologies competition. Another project that received money from it is the Human Brain Project which focuses on developing a highly detailed model of the brain.

The research teams will be researching graphene and its properties in order to find a way to use it most efficiently and maybe even combine it with silicone. They hope that graphene will be applicable in the industry because it is an excellent electricity conductor, stronger than steel, harder than diamond, has ideal optical properties and is as thin as currently possible. The research areas that will be covered in the first 30 months include ICT communications, physical transport and applications of graphene in energy, technology and sensors. The Flagship will also try not to conduct research on topics where research has already been conducted. In one of the press reports that were released from the Flagship they said that their precise focus will be on graphene production.

The research group includes, among others, representatives from Nokia and Airbus which will provide management support and four Nobel laureates, namely Andre Geim and Kostya Novoselov, the two researchers who discovered graphene, as well as German physicist Klaus von Klitzing and French physicist Albert Fert.

Research is also being conducted at the University of Cambridge that has its own Graphene Centre. They want to go from theory to practice and enable graphene to be used in the industry as soon as possible. The Cambridge Graphene Centre alone attracted £13m in financial support from Nokia, Dyson, Plastic Logic, Philips and BaE systems, with an additional £11m from the European Research Council.

Visit the website of Graphene Flagship to find out how their research is going:

http://graphene-flagship.eu/

XOXO A. 

CAJ #9 - Silicene

Silicene, an allotrope of silicon, was first created in 2010. It shares a lot of similarities with graphene. Both consist of a single layer of atoms, are strong, thin, flexible and very conductive. Graphene consists of carbon atoms and silicene of silicon atoms.

Silicene wires and sheets

Silicene could be of particular use in the semiconductor industry since this industry has already been using silicon for many years now. Also, it is easier to realize a so-called bandgap in silicene, which is a prerequisite for a transistor. Silicene could, just like graphene, be used in electronic devices. Furthermore, silicene could be used in the production of batteries. These would then have a longer life and would not continuously degenerate over time.

However, there is a catch to silicene. Researchers of the MESA+ Research Institute of the University of Twente recently succeeded in filming silicene directly and in real time. They let evaporated silicon atoms precipitate on a surface of silver, so that an almost closed, singular layer of silicene was formed. This showed that the material has suicidal tendencies.  As soon as a certain amount of silicon atoms fell on top of the silicene layer, a silicon crystal was formed. This crystal triggered the further crystallization of silicene. From that moment, the newly formed silicon began to “eat” the silicene.

This happens because the structure of regular silicon is more stable than that of silicene. This is the reason researchers could only cover 97% of the silver surface with silicene and could not create multi-layered silicene.  Unfortunately, this also means that it might not be possible to create multi-layered silicene on a different type of surface because they cannot even create a second layer of it.

XOXO A.

CAJ #8 - Stanene

So far I have only been talking about graphene as the new super material, as something that will revolutionize our world. But what if there is something as good as graphene or maybe even better? What if that something is stanene?

Stanene is a topological insulator. It is a material made from a single layer of tin atoms. It has been discovered by researchers from the US Department of Energy’s (DOE) SLAC National Accelerator Laboratory and Stanford University. The material was named stanene to liken it to graphene (plus the prefix of the Latin term for tin, stannum). However, stanene still has not been fabricated but when it does, it could be the world’s first electrical conductor that works at 100% efficiency at room temperature and above. This would make it even more conductive than graphene.

Stanene could increase the speed and lower the power needs of future generations of computer chips. This is still only a prediction but researchers as Stanford University, led by Shouchen Zhang, a physics professor ar Stanford, are currently conducting experiments in several laboratories to prove their predictions.

So far copper has been the number one material to carry electricity in various forms. Besides being cheap and conductive, it can also easily be drawn into strips. Modern chips the size of a thumbnail can contain up to sixty miles of copper wiring. The limits of copper are being pushed, channeling so much electricity through it that the material's electrical resistance causes wires to overheat. This could potentially set the whole device on fire. If researchers succeed in the production of stanene, computer chips could get smaller and faster without the risk of overheating. 

Earlier I mentioned stanene being a topological insulator. This means that its interior is an insulator but it conducts electrons along its surface. If stanene could be made only an atom thick, it would become all surface, thus it could conduct electricity with a 100% efficiency. As long as the topological insulators stay at the surface, the electrons will travel without resistance.

Researches claim that by adding fluorine to the mix, this level of efficiency can be preserved even at temperatures of up to 100 degrees Celsius. This would allow stanene to be used in computers where processors usually run at temperatures of between 40 and 90 degrees Celsius.

Although this is only a prediction since stanene faces many difficulties of manufacturing one-atom thick wires on an industrial scale and there is no working sample of the material available, Zhang is an optimist and has every reason to be one. He and his team have already predicted the properties of many topological insulators, such as mercury telluride, that were later confirmed experimentally.

It is still too soon to say when stanene will be used in the production of computer chips but it will happen, sooner or later. 

XOXO A. 

CAJ #7 - Potential use of graphene in solar cells

Solar cells are devices that convert the sun’s energy directly into electricity. They rely on the photoelectric effect - the ability of matter to emit electrons when a light is shone on it. Most of today’s solar cells are made out of silicon. However, silicon is very expensive because it is generally highly purified and then made into crystals that are sliced thin. Researchers have been trying to find an alternative that would be cheaper than silicon but have the same quality. Some believe the solution is inidium tin oxide, whereas others, namely MIT researchers, believe the answer is graphene. 

Silvija Gradček and eight other researchers at the  MIT, produced new graphene-based solar cells that are more flexible, lighter, and have a higher mechanical strength. The photovoltaic cell is based on sheets of flexible graphene coated with a layer of nanowires. This could lead to low-cost, transparent and flexible solar cells that could be set up on windows, roofs and other surfaces because of its low weight, mechanical strength and chemical robustness. This could potentially lead to the production of solar cells for households.

  

Graphene has a stable and inert structure, thus building a semiconducting nanostructure directly on its surface without damaging its electrical and structural properties has been a real challenge for researchers. They used a series of polymer coatings to modify its properties which allowed them to bond a layer of zinc oxide nanowires to it. Next they added an overlay of materials that respond to light waves. Throughout the whole process, graphene’s elemental properties remained intact.

1)  a flexible layer of graphene

2) a layer of polymer 

3) a layer of zinc-oxide nano wires (magenta color)

4) a layer of material that can extract energy from sunlight

The new graphene solar cells are not as efficient as certain types of silicon solar cells. Nonetheless, they are not far off the mark. Researchers will keep working on them in order to make them better and more efficient.  
So far the MIT research team has produced the graphene solar cell the size of only half an inch. It has not been proven yet that the technique can be used to create larger solar cells. Gradček says that it is only a matter of time when they will overcome this obstacle. She does not see that as a problem. Gradček claims that this technology could come on the market within the next couple of years. She hopes that this will make solar cells and solar power cheaper and available to the general public. 

XOXO A.