Friday, August 25, 2017

Carbon-Based: Graphene


wikipedia |  Graphene (/ˈɡræf.iːn/)[1][2] is an allotrope of carbon in the form of a two-dimensional, atomic-scale, hexagonal lattice in which one atom forms each vertex. It is the basic structural element of other allotropes, including graphite, charcoal, carbon nanotubes and fullerenes. It can be considered as an indefinitely large aromatic molecule, the ultimate case of the family of flat polycyclic aromatic hydrocarbons.

Graphene has many unusual properties. It is about 200 times stronger than the strongest steel. It efficiently conducts heat and electricity and is nearly transparent.[3] Graphene shows a large and nonlinear diamagnetism,[4] greater than graphite and can be levitated by neodymium magnets.
Scientists have theorized about graphene for years. It has unintentionally been produced in small quantities for centuries, through the use of pencils and other similar graphite applications. It was originally observed in electron microscopes in 1962, but it was studied only while supported on metal surfaces.[5] The material was later rediscovered, isolated, and characterized in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester.[6][7] Research was informed by existing theoretical descriptions of its composition, structure, and properties.[8] This work resulted in the two winning the Nobel Prize in Physics in 2010 "for groundbreaking experiments regarding the two-dimensional material graphene."[9]

The global market for graphene reached $9 million by 2012 with most sales in the semiconductor, electronics, battery energy, and composites industries.[10]
 
NewYorker |  Perhaps the most expansive thinker about the material’s potential is Tomas Palacios, a Spanish scientist who runs the Center for Graphene Devices and 2D Systems, at M.I.T. Rather than using graphene to improve existing applications, as Tour’s lab mostly does, Palacios is trying to build devices for a future world.

At thirty-six, Palacios has an undergraduate’s reedy build and a gentle way of speaking that makes wildly ambitious notions seem plausible. As an electrical engineer, he aspires to “ubiquitous electronics,” increasing “by a factor of one hundred” the number of electronic devices in our lives. From the perspective of his lab, the world would be greatly enhanced if every object, from windows to coffee cups, paper currency, and shoes, were embedded with energy harvesters, sensors, and light-emitting diodes, which allowed them to cheaply collect and transmit information. “Basically, everything around us will be able to convert itself into a display on demand,” he told me, when I visited him recently. Palacios says that graphene could make all this possible; first, though, it must be integrated into those coffee cups and shoes.

As Mody pointed out, radical innovation often has to wait for the right environment. “It’s less about a disruptive technology and more about moments when the linkages among a set of technologies reach a point where it’s feasible for them to change lots of practices,” he said. “Steam engines had been around a long time before they became really disruptive. What needed to happen were changes in other parts of the economy, other technologies linking up with the steam engine to make it more efficient and desirable.”

For Palacios, the crucial technological complement is an advance in 3-D printing. In his lab, four students were developing an early prototype of a printer that would allow them to create graphene-based objects with electrical “intelligence” built into them. Along with Marco de Fazio, a scientist from STMicrolectronics, a firm that manufactures ink-jet print heads, they were clustered around a small, half-built device that looked a little like a Tinkertoy contraption on a mirrored base. “We just got the printer a couple of weeks ago,” Maddy Aby, a ponytailed master’s student, said. “It came with a kit. We need to add all the electronics.” She pointed to a nozzle lying on the table. “This just shoots plastic now, but Marco gave us these print heads that will print the graphene and other types of inks.”