Tin + Graphene -- Stanene is a conductive material theorized for nearly 100 percent efficiency

Stanford Linear Accelerator researchers have developed a material that may be the holy grail of conductivity -- a material that permits almost 100 percent conductivity between a power source and destination.

Tin (Sn) is a " dull-gray powdery material with no common uses"¹, but as an alloy is known for its anti-corrosive properties.²  Combined with the flexible structural integrity of graphene, it creates a nearly-perfect medium for tin's diamond-shaped and inherently covalent nature to "bridge the gap".    The covalent bonding is so strong that electricity can flow literally without losing electrons.

graphic from Wikipedia: The diamond-lattice covalent atomic structure of Sn

Coined "Stanene", this material may soon be replacing copper as the relay of choice for newer-generation electronic circuits.  Copper, while inexpensive and ductile, is susceptible to overheating.   Legacy chips, such as the "POWER3-II chip — about the size of a thumbnail — contains a quarter mile of copper wiring." ³.

More modern electronic circuits may contain several miles of copper "wire" -- sometimes just an atom thick.  High-voltage electricity pushed through such narrow channels may cause the wires to melt and cause electronic components to catch fire.   Stanene would overcome such constraints by allowing the flow to distribute through the "channel of least resistance" more efficiently.

At present, Stanene is but a theoretical, though franchisable "wonder material"; as reported by The Independent,

there are many obstacles standing between stanene and mainstream use (not limited to the difficulties of manufacturing one-atom thick wires on an industrial scale) and without working samples of the material available it is perhaps a little early to get excited.

Making the Internet go faster with graphene-enhanced switches

Just how tough is graphene?  Researchers have theorized that it'd require an elephant, balanced on a pencil, to break through a single sheet.  Every industry, it seems, has been grazed by graphene's wondrous potential -- the strength, light-weight nature (a single sheet of carbon atoms so thin it's actually transparent), flexibility and conductivity can be replicated at a relatively low cost and applied to a plethora of materials.

The latest industry it may soon help -- telecom.   How?  Enhancing switches to increase speed of data transfer rates. 

"Ordinarily optical switches respond at rate of a few picoseconds – around a trillionth of a second. Through this study physicists have observed the response rate of an optical switch using ‘few layer graphene’ to be around one hundred femtoseconds – nearly a hundred times quicker than current materials."

How would this technology be implemented?  Commenting on the report’s main findings, lead researcher Dr Enrico Da Como noted:

"Right now the capacity for data transfer in fibre optics is below a terabit per second,” he says. “But graphene will allow us to reach the one terabit per second rate ... It will take some years and there is engineering development to be done, but I think it will be in about four or five years. We are working on the first prototypes now." 

sources:  

•  http://www.bath.ac.uk/news/2013/07/12/graphene-internet-speed
• http://www.information-age.com/technology/mobile-and-networking/123457194/graphene-based-optical-switches-promise-lightning-fast-networks
• http://www.gizmag.com/graphene-faster-internet/28382/

“Right now the capacity for data transfer in fibre optics is below a terabit per second,” he says. “But graphene will allow us to reach the one terabit per second rate.
“It will take some years and there is engineering development to be done, but I think it will be in about four or five years. We are working on the first prototypes now.”
- See more at: http://www.information-age.com/technology/mobile-and-networking/123457194/graphene-based-optical-switches-promise-lightning-fast-networks--#sthash.SP1VkbfO.dpuf

“Right now the capacity for data transfer in fibre optics is below a terabit per second,” he says. “But graphene will allow us to reach the one terabit per second rate.
“It will take some years and there is engineering development to be done, but I think it will be in about four or five years. We are working on the first prototypes now.”
- See more at: http://www.information-age.com/technology/mobile-and-networking/123457194/graphene-based-optical-switches-promise-lightning-fast-networks--#sthash.SP1VkbfO.dpuf

“Right now the capacity for data transfer in fibre optics is below a terabit per second,” he says. “But graphene will allow us to reach the one terabit per second rate.
“It will take some years and there is engineering development to be done, but I think it will be in about four or five years. We are working on the first prototypes now.”
- See more at: http://www.information-age.com/technology/mobile-and-networking/123457194/graphene-based-optical-switches-promise-lightning-fast-networks--#sthash.SP1VkbfO.dpuf

'Printable' Graphene ink writes circuits

CleanTechnica is reporting that a new method of "exfoliating" graphene from blocks of graphite has been developed. "The graphene is being used to develop a low cost, highly conductive ink that can be used to print electronic circuits on flexible material, leading to the next generation of tiny, foldable, mobile electronic devices."

Graphene, interrupted

One of the biggest challenges in working with a material whose chemical-binding properties are contingent upon physical construction is getting that material to "stay put" in its physical form long enough to get the material to do its chemical thing.

crinkled graphene

Graphene's physical construction is often likened to chicken wire, one atom thick; but when it is "unrolled" it can easily contract and constrict in upon itself,  "crumpling" like the skin of a grape into a raisin that has been left in the heat and sun too long.    In its crumpled form, graphene behaves differently, and is significantly more difficult to handle.  

But new research by Duke University offers a new technique for getting the graphene to un-crumple itself.   By adhering the graphene to a rubber film, the chicken wire lattice's crumpling can be controlled and flexed on demand: 

"Duke engineers attached the graphene on a rubber film that had been pre-stretched multiple times of its original size. Once the pre-stretch in the rubber film was relaxed, part of the graphene detached from the rubber while other part kept adhering on the rubber, forming an attached-detached pattern with a size of a few nanometers. As the rubber was relaxed, the detached graphene was compressed to crumple. Once the rubber film was stretched back, the adhered graphene will pull on the crumpled graphene to unfold it."  source: http://www.sciencedaily.com/releases/2013/01/130123165042.htm

This process opens up new frontiers for application such as artificial muscle, which needs a large surface area that can be "deformed" as the muscles constrict and relax naturally.

Xuanhe Zhao, one of the engineers researching this application said, "In particular, they promise to greatly improve the quality of life for millions of disabled people by providing affordable devices such as lightweight prostheses and full-page Braille displays. The broad impact of new artificial muscles is potentially analogous to the impact of piezoelectric materials on the global society."    

A sponge to soak up radioactive waste

Flakes of graphene oxide have a "spongelike" quality that can be used to bind to and solidify radioactive waste.  Once in solid form, the contaminated material can be easily collected and cleaned up.

"Capturing radionuclides does not make them less radioactive, just easier to handle. Where you have huge pools of radioactive material, like at Fukushima, you add graphene oxide and get back a solid material from what were just ions in a solution," said chemist James Tour of Rice University. "Then you can skim it off and burn it. Graphene oxide burns very rapidly and leaves a cake of radioactive material you can then reuse."

The large surface area of graphene oxide particles means that they have an increased ability to adsorb and bond with other materials, specifically those with toxic quality which tend to have volatile chemical properties.  The honeycomb lattice of graphene can bond to and essentially stabilize them.     

source: http://www.sciencedaily.com/releases/2013/01/130108112459.htm

Scientists at Rice University and Lomonosov Moscow State University have developed the new method for removing radioactive material. In the flask on the left, the solution contains the particles of graphene oxide (atom thick flakes);  on the right the particles have bonded to simulated radioactive material.

Practical applications range from cleanup of sites such as the Fukushima nuclear power plant to fracking -- or using graphene to filter out contaminants from the water.  "Hot" radioactive water normally needs to be shipped to various containment facilities around the country, which is done so at great expense.

Nanotubular awesomeness

Single-walled carbon nanotubes (SWCNT) are vertical hollow structures comprised of carbon atoms enjoined via industrial-strength hexagonal lattice.  Scientists at Rice University have published research  into a method of "gluing" the SWCNTs to sheets of graphene that maintain the ohmic properties of the bond.

Picture chicken wire that is stronger than steel, yet able to conduct electricity.  Comparatively, copper (Cu) and gold (Au) -- two traditionally "conductive" materials are soft and would never be able to support comparative structures of these relative heights.  Just as an ant is able to lift ~50 times their body weight, these carbon nanotube structures are able to scale to heights beyond imagination -- "up to a distance of 120 microns (0.12mm), which is really rather impressive at this scale. If we scaled it up to actual trees, they would rise into outer space," reports ExtremeTech.

This microcosm of tubular awesomeness is significant because it means that the surface area of a base can actually support much more "storage" power.    That is, supercapacitors, lithium-ion batteries, and other kinds of energy storage may  be able do do more with less. Denser energy storage structures mean longer-life batteries in a smaller space. 

Screening pollutants

Research sponsored by the National Science Foundation and DARPA Research Center for Micro/Nano-Electromechanical Transducers has garnered some breakthroughs in what could be the next era of pollution reduction.

Graphene membranes, which are known to be selectively porous, exhibit the capability to screen out pollutants by separating inert carbon dioxide molecules from larger, more potentially harmful ones, such as nitrogen and sulphur hexaflouride.   The graphene membranes work especially well for gaseous "pollutant" materials because of the semi-permeable nature of graphene membranes.

Illustration by Zhangmin Huang

"The findings are a significant step toward the realization of more energy-efficient membranes for natural gas production and for reducing carbon dioxide emissions from power plant exhaust pipes," reports the University of Colorado at Boulder, where much of the research took place.  "Those characteristics make graphene an ideal material for creating a separation membrane because it is durable and yet doesn’t require a lot of energy to push molecules through it, he said."

Given these findings, may I hypothesize about some other related applications --  Radiation containment?   Automobile exhaust pipes?  Chimney screens?

As with any recent breakthrough, there are some logistical challenges to be overcome before the applications can be widely applied.    For example, "creating large enough sheets of graphene to perform separations on an industrial scale, and developing a process for producing precisely defined nanopores of the required sizes are areas that need further development. The CU-Boulder experiments were done on a relatively small scale."

Extending memory beyond Moore's Law

Red Orbit is reporting that researchers at Rice University have been able to combine the almost ionic properties of graphene with the light-penetrable properties of Silicon Oxide to design what amounts to flexible and transparent 3D, two-terminal memories. 

"[The] highly transparent, nonvolatile resistive memory devices are based on the revelation that silicon oxide can be a switch  At just 5 nanometers, a channel can be created to extend memory beyond Moore’s Law, which predicts computer circuitry will double in power every two years.

Manufacturers are finding physical limits on current architectures when trying to fit millions of bits on small devices. Currently, electronics are made with 22 nanometer circuits.

Combining silicon and graphene enables the scientists to extend the possibilities of where memory can be placed. The devices could not only have potential for facing the harsh conditions of radiation, but also could be able to withstand heat of up to about 1,300 degrees Fahrenheit.

source:  http://www.redorbit.com/news/technology/1112706299/graphene-flexible-transparent-memory-100312/?print=true

Stepping down from 22 to 5 nanometers may not seem like a huge leap, but thus far it has presented some logistical challenges.  Up to this point, the primary limitation in down-sizing circuitry has been in finding materials that can retain their "transmission" properties at such small diameters.  As explained by Dr. James Tour, "We need transparent wires to wire them together and bring in the needed voltages and record the currents."

So what is it that makes graphene so special?  

"Graphene, being transparent, is being used as the wiring for both the input and output electrodes on the plastic substrates," he explained further.  "On the glass substrates, we use indium-tin-oxide (ITO), a transparent metallic electrode for the input and graphene on top for the output.”

Boosting the anti-corrosive properties of copper

A microscopic layer of graphene atoms coating a simple copper wire can boost the anti-corrosive properties of that wire by up to 100 times, reports Science Direct

Pure copper is one of the softest and most malleable metals, and copper ions alone are water-soluble. But with the application of a single layer of graphene atoms, the wire can stand up to much more harsh environments.
The implications are for better "insulation" materials allowing copper to be used in places where it otherwise wouldn't make sense.

The researchers applied the graphene to copper at temperatures between 800 and 900 degrees, using a technique known as chemical vapour deposition, and tested it in saline water. “In nations like Australia, where we are surrounded by ocean, it is particularly significant that such an atomically thin coating can provide protection in that environment,” Dr Banerjee said. Initial experiments were confined to copper, but Dr Banerjee said research was already under way on using the same technique with other metals. This would open up uses for a huge range of applications, from ocean-going vessels to electronics: anywhere that metal is used and at risk of corrosion. Such a dramatic extension of metal’s useful life could mean tremendous cost savings for many industries.

source: http://www.sciencedirect.com/science/article/pii/S0008622312003636
source: http://www.nanowerk.com/news2/newsid=26835.php

Downsides to the science

Amazing as it is, there appear to be some potential downsides to the amazing graphene. 

Two recent stories stick out in my constant perusal of this topic. The first is potential danger to individuals, the second is a potential downside to our fragile ecosystem.

The first one discusses the downside of carbon nanotubes as they can essentially "trap" cancer cells

source:  nanotube posts from technewsdaily

According to a new study conducted by researchers at Brown University, nanomaterials such as carbon nanotubes mimic asbestos and can fool our cells into thinking they are big enough to ingest, leading to some disastrous results. This is the same thing that makes asbestos dangerous, a process lead researcher Huajian Gao compared to eating a lollipop that's bigger than your own body — it would get stuck.

The second source of danger appears even more disturbing, as the extremely durable, pliant and "resistant" materials that graphene can enhance end up being toxic to many aquatic animals:

Nickel, chromium and other metals used in the manufacturing process can remain as impurities. Deng and his colleagues found that these metals and the CNTs themselves can reduce the growth rates or even kill some species of aquatic organisms. The four species used in the experiment were mussels (Villosa iris), small flies' larvae (Chironomus dilutus), worms (Lumbriculus variegatus) and crustaceans (Hyalella azteca).

 source

"Zapped" graphene increases power density of lithium-ion batteries

That which doesn't kill it makes it stronger . . . Research has revealed that the action of "zapping" a sheet of graphene with a laser or super-concentrated camera flash actually helps it become a more powerful anode for lithium ion batteries. It works because the damage done to the sheet allows the ions to cycle more quickly through the cracks and newly-created pores, without damaging the actual charging ability of the battery.

The new material is made from graphene, which is the world's thinnest material. They took a sheet of graphene and blasted it with a camera flash or laser to deform it, causing several pores and cracks. This made the graphene sheet a great anode for lithium ion batteries because the lithium ions could cut through the pores/cracks to charge and discharge rather than run the entire length of graphene (which took much longer). This ultimately increased the power density. Source

Other research revealed graphene's self-healing capacity to "knit" itself back together. Hole-burning "metals" which were initially thought to damage sheets of graphene were later discovered to magically mend themselves. Source