AFM image of crystallographic structure of a sheet of graphene. Credit: Jarillo-Herrero group

A recent article in MIT Tech Talk describes aspects of several exciting graphene research projects at MIT.

A successor to silicon? Graphene could become the successor to silicon in a new generation of microchips because of its unique electrical characteristics. Graphene could surmount the basic physical constraints that limit further development of smaller, faster chips.

Transparent electrodes? Pure graphene is transparent because of its single-atom thickness. Therefore, it can be used to make transparent electrodes for light-based applications, such as LEDs or solar cells.

Substitute for copper? Graphene also could substitute for copper to make the electrical connections between computer chips and other electronic devices. This would provide lower resistance and generate less heat.

AFM of graphene superconducting FET. The two gold-colored electrodes are made of superconducting titanium-aluminum alloy. Credit: Jarillo-Herrero group

Study quantum-mechanical effects? A team led by Pablo Jarillo-Herrero, an assistant professor of physics, is studying its basic physical properties and using graphene’s unique behavior as a way to study fundamental quantum-mechanical effects. For example, in graphene, electrons behave as if they were massless particles that propagate according to the laws of relativistic quantum mechanics, a behavior that is normally reserved to particles traveling near the speed of light in accelerators or in the cosmos. Such behavior is at the heart of the ultrahigh mobilities exhibited by graphene devices. Jarillo-Herrero says that because the material is so new and its fundamental properties still being discovered, “we have some applications in mind, but many totally new ones will for sure come up as we continue doing research.”

Graphene production? Another team, led by Jing Kong, the ITT Career Development Associate Professor of Electrical Engineering, is working on developing commercial methods to produce the material in greater quantities. The team has created sheets of graphene by chemical vapor deposition. Kong’s method uses equipment that is “very compatible to conventional semiconductor processing.” The method “is quite straightforward, and not too expensive,” she says. That’s good news for commercial applications. For specialized functions, such as computer chips, further research will be needed to improve the quality and uniformity of the graphene sheets, she says, but for other applications, such as solar-cell electrodes, the existing process allows the researchers to start the investigation.

The MIT article also includes an excellent review of the structure, properties and history of graphene.

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Have you heard the joke about running a bus with water from Lake Erie? Well, it’s no laughing matter these days. In fact, it’s scheduled to happen about a year from now. NASA’s Glenn Research Center actually plans to pump water from the Cleveland shore of Lake Erie and harvest its hydrogen to run a transit bus.

The hydrogen fueling station will be located in downtown Cleveland at the Great Lakes Science Center, the site of an existing wind and solar energy power sources. A unique, high-capacity electrolyzer will use these energy sources to separate nearby Lake Erie water to hydrogen and oxygen. The hydrogen will be used to operate a Greater Cleveland Regional Transit Authority bus built by United Technologies that is powered by fuel cells. The bus will be operated in revenue service and will be identified by the little bit of water coming out of the tailpipe.

“What we’re proposing is to give a full-scale demonstration of taking renewable energy off of a wind machine or photovoltaic grid, using that energy to power a water electrolyzer to break down water into hydrogen and oxygen and then use that hydrogen as a fuel in a fuel cell-powered vehicle,” says Paul Prokopius, an energy consultant and retired NASA fuel cell researcher.” He continues, “They produce water vapor and clean water – nothing else. It’s totally zero emission.”

“The project is more than a key technology demonstration,” says Valerie Lyons, project team leader and chief of Glenn’s Power and In-Space Propulsion Division. “It will be a great educational tool for the public and will serve as a catalyst to inspire new ideas and initiatives that can create many new jobs and manufacturing opportunities in Ohio,” she added.

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Warner Philips, founder of Lemnis Lighting Co. in The Netherlands, claims “CFLs are officially an outdated technology. You can’t recycle CFLs. You can’t get a fully dimmable product. That should make them obsolete.”

This is quite a statement, considering compact fluorescent lamps are just now beginning to replace incandescent lamps.

Philips makes this bold statement based on a new 6-watt LED light bulb his company recently introduced at Lightfair International in New York. He has named the bulb the “Pharox LED Light” and claims that it is equivalent to a 60-watt incandescent light bulb. Unlike most CFL bulbs, the Pharox can be used with dimmer switches and contains no mercury. The LED bulb is supposed to have a life of 36,000 hours or 25 years, eight times longer than a CFL bulb.

Of course, all these advantages come at a cost. Lemnis already sells a 5-watt LED bulb, claimed to be equivalent to a 40-watt incandescent lamp, for about $35, down from its price six months ago of $40. The 6-watt version is set to sell for $50.00 on Amazon.com. Philips believes that the cost of the bulbs will decrease rather quickly.

The 5-watt LED bulb is being sponsored by the Clinton Climate Initiative in Europe and 2.5 million will distributed there.

As always, there is a downside. The LED bulbs last 25 percent less time when used in enclosed fixtures. I am more concerned that the 5-watt LED bulb is advertised to produce about 300 lumens, whereas the familiar 60-watt incandescent bulb produces 900 lumens. The question will be whether these negatives are acceptable considering the benefits of eliminating mercury and recycling.

The Lemnis Lighting site includes a sidebar that states, “If every Dutch household were to replace 4 incandescent bulbs with 4 Pharox lamps, we would save 1.5 billion kWh of energy per year. This energy saving is equal to the annual energy consumption of all households in Amsterdam.”

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If you do a Google search of “top ten,” you get more than 90 million hits – from David Letterman, to New Year’s resolutions, to urinals (which is another ceramics story).

The list I want to share with you here deals with the patent strength and research prowess of U.S. universities. I suppose there are many ways to select the top ten research schools. What I found was a ranking of “Pipeline Power” created by IEEE Spectrum. The score is calculated using growth in patent activity, frequency of citations, number and variety of technologies drawing on the patents, and originality based on the variety of existing technologies the patents build on.

The nominees are MIT, Cal Tech, University of California, Harvard, Rice, Texas, Central Florida, Georgia Tech, Stanford and Wisconsin. The envelope please. And the winner is . . . MIT!

Also in the rankings business is Small Times. This website focused on microtechnology and nanotechnology in its “2009 University Report and Rankings.” Questionnaires and peer reviews were used in this study. Winners were identified for several categories:

• SUNY-Albany (Commercialization)
• Penn State (Research)
• MIT (Peer Nano Research)
• Univ. of California, Berkeley (Peer Micro Research)
• MIT (Peer Nano Commercialization)
• Univ. of California, Berkeley (Peer Micro Commercialization)

Penn State received high research marks because of its facilities, staff, funding, students, degrees conferred and papers presented. SUNY-Albany scored high in spinoffs, patents awarded and IP licenses based on its micro/nano patents, startups and number of companies using faculty.

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Researchers at Rensselaer Polytechnic Institute believe that the speed at which heat moves between two materials that touch one another indicates the strength of the bond between them. Moreover, they believe that flow of heat from one material to the other – in their case, between one solid and one liquid – can be altered by painting a thin atomic layer between the materials. That is, when the interface changes, the interaction between the materials changes.

“If you have a nanoparticle that is inside a liquid solution, you can’t just ‘peel away’ the liquid to measure how strongly it is bonded to the surrounding molecules,” says Pawel Keblinski, professor in RPI’s Department of Materials Science and Engineering. Keblinski, who co-led the study, further says, “Instead, we show that you can measure the strength of these bonds simply by measuring the rate of heat flow from the nanoparticle to the surrounding liquid.”

Shekhar Garde, who co-led the study with Keblinski, states, “Interfaces are an exciting new frontier for doing fundamental studies of this type. If you peek into complex biological systems – a cell, for example – they contain a high density of interfaces, between different proteins or between protein and water.” Garde, who is Elaine and Jack S. Parker Professor and head of RPI’s Department of Chemical and Biological Engineering, also says, “Our approach possibly provides another handle to quantify how proteins talk to each other or with the surrounding water.”

Kablinski and Garde used molecular dynamics simulations to measure the heat flow between solid surfaces and water. They simulated many surface chemistries and found that thermal conductance was directly proportional to how strongly the liquid adhered to the solid.

“In the case of a mercury thermometer, thermal expansion correlates directly with temperature,” Keblinski says. “What we have done, in a sense, is create a new thermometer to measure the interfacial bonding properties between liquids and solids.”

“We can use this new technique to characterize systems that are very difficult or impossible to characterize by other means,” Garde adds.

Garde continues, “This fundamental discovery, which helps to better understand how water sticks to or flows past a surface, has implications for many different heat transfer applications and processes, including boiling and condensation. Of particular interest is how this discovery can benefit new systems for cooling and displacing heat from computer chips, a critical issue currently facing the semiconductor industry.”

The authors conclude that the study provides new information of the behavior of water at various solid interfaces.

This study, titled “How wetting and adhesion affect thermal conductance of a range of hydrophobic to hydrophilic aqueous solutions,” was published April 13, 2009, by Physical Review Letters. Co-authors of the study include RPI graduate students Natalia Shenogina and Rahul Godawat.

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