Cool nanotech image — graphene

Actually the accompanying article is pretty cool, too, so do take the time to check it out.

But now, the image …

This image of a single suspended sheet of graphene taken with the TEAM 0.5, at Berkeley Lab’s National Center for Electron Microscopy shows individual carbon atoms (yellow) on the honeycomb lattice.

Also from the link:

In the current study, the team made graphene nanoribbons using a nanowire mask-based fabrication technique. By measuring the conductance fluctuation, or ‘noise’ of electrons in graphene nanoribbons, the researchers directly probed the effect of quantum confinement in these structures. Their findings map the electronic band structure of these graphene nanoribbons using a robust electrical probing method. This method can be further applied to a wide array of nanoscale materials, including graphene-based electronic devices.

“It amazes us to observe such a clear correlation between the noise and the band structure of these graphene nanomaterials,” says lead author Guangyu Xu, a physicist at University of California, Los Angeles. “This work adds strong support to the quasi-one-dimensional subband formation in graphene nanoribbons, in which our method turns out to be much more robust than conductance measurement.”

One more bit from the link, from the intro actually:

In last week’s announcement of the Nobel Prize in Physics, the Royal Swedish Academy of Sciences lauded graphene’s “exceptional properties that originate from the remarkable world of quantum physics.” If it weren’t hot enough before, this atomically thin sheet of carbon is now officially in the global spotlight.

So expect to hear a lot more about graphene in the coming months. Of course if you’re a regular reader of this blog, you’ve been getting a pretty steady (aside from the last month of light blogging) diet of graphene since almost day one (since February 2008 to be exact).

Graphene transistors hit 300 GHz

Via KurzweilAI.net — Great news, but as always I’d love to see a market-ready application come out of this research in the near future. Blogging about nanotech breakthroughs is all well and good, but it is excellent when I get the chance to blog about a real-world application of said breakthroughs.

From the link:

High-speed graphene transistors achieve world-record 300 GHz

September 3, 2010 by Editor

UCLA researchers have fabricated the fastest  graphene transistor to date, using a new fabrication process with a  nanowire as a self-aligned gate.

Self-aligned gates are a key element in modern transistors, which are semiconductor devices used to amplify and switch electronic signals.  Gates are used to switch the transistor between various states, and self-aligned gates were developed to deal with problems of misalignment encountered because of the shrinking scale of electronics.

“This new strategy overcomes two limitations previously encountered in graphene transistors,” professor of chemistry and biochemistry Xiangfeng Duan said. “First, it doesn’t produce any appreciable defects in the graphene during fabrication, so the high carrier mobility is retained. Second, by using a self-aligned approach with a nanowire as the gate, the group was able to overcome alignment difficulties previously encountered and fabricate very short-channel devices with unprecedented performance.”

These advances allowed the team to demonstrate the highest speed graphene transistors to date, with a cutoff frequency up to 300 GHz — comparable to the very best transistors from high-electron mobility materials such gallium arsenide or indium phosphide.

Graphene, a one-atom-thick layer of graphitic carbon, has great potential to make electronic devices such as radios, computers and phones faster and smaller. With the highest known carrier mobility — the speed at which electronic information is transmitted by a material — graphene is a good candidate for high-speed radio-frequency electronics. High-speed radio-frequency electronics may also find wide applications in microwave communication, imaging and radar technologies.

Funding for this research came from the National Science Foundation and the National Institutes of Health.

More info: UCLA news

The internet turns forty

People carry on about how it’s well past the year 2000 and just exactly where is the future we all imagined — flying cars, jet packs, the works.

Well, think about what someone from 1985 would say about pretty much everyone carrying tiny devices that combine cordless phones, mini-televisions, the internet, etc. Put their jaw back in place and go to a hoary old desktop computer with a broadband connection. The computer might look somewhat similar, but even a user of the internet (probably a scientist or academic) from that year would be bowled over by the sheer volume of information, rich media and connectivity availble today.

From the link:

Goofy videos weren’t on the minds of Len Kleinrock and his team at UCLA when they began tests 40 years ago on what would become the Internet. Neither was social networking, for that matter, nor were most of the other easy-to-use applications that have drawn more than a billion people online.

Instead the researchers sought to create an open network for freely exchanging information, an openness that ultimately spurred the innovation that would later spawn the likes of YouTube, Facebookand the World Wide Web.

There’s still plenty of room for innovation today, yet the openness fostering it may be eroding. While the Internet is more widely available and faster than ever, artificial barriers threaten to constrict its growth.

Call it a mid-life crisis.

A variety of factors are to blame. Spam and hacking attacks force network operators to erect security firewalls. Authoritarian regimes block access to many sites and services within their borders. And commercial considerations spur policies that can thwart rivals, particularly on mobile devices like the iPhone.

“There is more freedom for the typical Internet user to play, to communicate, to shop — more opportunities than ever before,” saidJonathan Zittrain, a law professor and co-founder of Harvard’s Berkman Center for Internet & Society. “On the worrisome side, there are some longer-term trends that are making it much more possible (for information) to be controlled.”

Few were paying attention back on Sept. 2, 1969, when about 20 people gathered in Kleinrock’s lab at the University of California, Los Angeles, to watch as two bulky computers passed meaningless test data through a 15-foot gray cable.

CIGS-based solar cells ready for prime time

If CIGS-based solar cells are ready for commercial production this could be a major solar power breakthrough.

The release:

Low-cost solution processing method developed for CIGS-based solar cells

The method could provide an answer to a manufacturing issue

Though the solar industry today predominately produces solar panels made from crystalline silicon, they remain relatively expensive to make. New players in the solar industry have instead been looking at panels that can harvest energy with CIGS (copper-indium-gallium-selenide) or CIGS-related materials. CIGS panels have a high efficiency potential, may be cheaper to produce and would use less raw materials than silicon solar panels. But unfortunately, manufacturing of CIGS panels on a commercial scale has thus far proven to be difficult.

Recently researchers at the UCLA Henry Samueli School of Engineering and Applied Science have developed a low-cost solution processing method for CIGS-based solar cells that could provide an answer to the manufacturing issue. In a new study to be published in the journal Thin Solid Films on July 7, Yang Yang, a professor in the school’s Department of Materials Science and Engineering, and his research team show how they have developed a low-cost solution processing method for their copper-indium-diselenide solar cells which have the potential to be produced on a large scale.

“This CIGS-based material can demonstrate very high efficiency,” said William Hou, a graduate student on Yang’s team and first author of the study. “People have already demonstrated efficiency levels of up to 20 percent, but the current processing method is costly. Ultimately the cost of fabricating the product makes it difficult to be competitive with current grid prices. However, with the solution process that we recently developed, we can inherently reach the same efficiency levels and bring the cost of manufacturing down quite significantly.”

The copper-indium-diselenide thin-film solar cell developed by Yang’s team achieved 7.5 percent efficiency in the published study but has in a short amount of time already improved to 9.13 percent in the lab.

“We started this process 16 months ago from ground zero. We spent three to four months getting the material to reach 1 percent and today it’s around 9 percent. That is about an average increase of 1 percent every two months,” said Yang, also a member of the California NanoSystems Institute, where some of the work is being done.

Currently, most CIGS solar cells are produced using vacuum evaporation techniques called co-evaporation, which can be costly and time-consuming. The active elements — copper, indium, gallium and selenide — are heated and deposited onto a surface in a vacuum. Using vacuum processing to create CIGS films with uniform composition on a large scale has also been challenging.

The copper-indium-diselenide material created by Yang’s team does not need to go through the vacuum evaporation process. Their material is simply dissolved into a liquid, applied and baked. To prepare the solution, Yang’s team used hydrazine as the solvent to dissolve copper sulfide and indium selenide in order to form the constituents for the copper-indium-diselenide material. In solar cells, the “absorber layer” (either copper-indium-diselenide or CIGS) itself is the most critical to performance and the most difficult to control. Their copper-indium-diselenide layer, which is in solution form, can be easily painted or coated evenly onto a surface and baked.

“In our method, material utilization is one advantage. Another advantage is our solution technology has the potential to be fabricated in a continuous roll-to-roll process. Both are important breakthroughs in terms of cost,” said Hou.

The team’s goal is to reach an efficiency level of 15 to 20 percent. Yang predicts three to four years before commercialization.

“As we continue to work on enhancing the performance and efficiency of the solar cells, we also look forward to opportunities to collaborate with industry in order to develop this technology further. We hope this technology will lead to a new green energy company in the U.S., especially here in California so that it may also bring job opportunities to many who need it,” said Yang.

 

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The study was funded in part by the NSF Integrative Graduate Education and Research Traineeship-Materials Creation Training Program.

The Department of Materials Science and Engineering is part of the UCLA Henry Samueli School of Engineering and Applied Science, established in 1945, offers 28 academic and professional degree programs, including an interdepartmental graduate degree program in biomedical engineering. Ranked among the top 10 engineering schools at public universities nationwide, the school is home to five multimillion-dollar interdisciplinary research centers in wireless sensor systems, nanotechnology, nanomanufacturing and nanoelectronics, all funded by federal and private agencies.

Stem cell news — differences and ethics

Two releases from yesterday on stem cells. Number one is on the found differences between reprogrammed skin cells and embryonic stem cells. Second is a call for stem cell debates by bioethicists before the science gets too far ahead of ethical considerations.

The first release:

UCLA scientists find molecular differences between embryonic stem cells and reprogrammed skin cells

UCLA researchers have found that embryonic stem cells and skin cells reprogrammed into embryonic-like cells have inherent molecular differences, demonstrating for the first time that the two cell types are clearly distinguishable from one another.

The data from the study suggest that embryonic stem cells and the reprogrammed cells, known as induced pluripotent stem (iPS) cells, have overlapping but still distinct gene expression signatures. The differing signatures were evident regardless of where the cell lines were generated, the methods by which they were derived or the species from which they were isolated, said Bill Lowry, a researcher with the Broad Stem Cell Research Center and a study author.

“We need to keep in mind that iPS cells are not perfectly similar to embryonic stem cells,” said Lowry, an assistant professor of molecular, cell and developmental biology. “We’re not sure what this means with regard to the biology of pluripotent stem cells. At this point our analyses comprise just an observation. It could be biologically irrelevant, or it could be manifested as an advantage or a disadvantage.”

The study appears in the July 2, 2009 issue of the journal Cell Stem Cell.

The iPS cells, like embryonic stem cells, have the potential to become all of the tissues in the body. However, iPS cells don’t require the destruction of an embryo.

The study was a collaboration between the labs of Lowry and UCLA researcher Kathrin Plath, who were among the first scientists and the first in California to reprogram human skin cells into iPS cells. The researchers performed microarray gene expression profiles on embryonic stem cells and iPS cells to measure the expression of thousands of genes at once, creating a global picture of cellular function.

Lowry and Plath noted that, when the molecular signatures were compared, it was clear that certain genes were expressed differently in embryonic stem cells than they were in iPS cells. They then compared their data to that stored on a National Institutes of Health data base, submitted by laboratories worldwide. They analyzed that data to see if the genetic profiling conducted in other labs validated their findings, and again they found overlapping but distinct differences in gene expression, Lowry said.

“This suggested to us that there could be something biologically relevant causing the distinct differences to arise in multiple labs in different experiments,” Lowry said. “That answered our first question: Would the same observation be made with cell lines created and maintained in other laboratories?”

Next, UCLA researchers wanted to confirm their findings in iPS cell lines created using the latest derivation methods. The cells from the UCLA labs were derived using an older method that used integrative viruses to insert four genes into the genome of the skin cells, including some genes known to cause cancer. They analyzed cell lines derived with newer methods that do not require integration of the reprogramming factors. Their analysis again showed different molecular signatures between iPS cells and their embryo-derived counterparts, and these signatures showed a significant degree of overlap with those generated with integrative methods.

To determine if this was a phenomenon limited to human embryonic stem cells, Lowry and Plath analyzed mouse embryonic stem cells and iPS lines derived from mouse skin cells and again validated their findings. They also analyzed iPS cell lines made from mouse blood cells with the same result

“We can’t explain this, but it appears something is different about iPS cells and embryonic stem cells,” Lowry said. “And the differences are there, no matter whose lab the cells come from, whether they’re human or mouse cells or the method used to derive the iPS cells. Perhaps most importantly, many of these differences are shared amongst lines made in various ways.”

Going forward, UCLA researchers will conduct more sophisticated analyses on the genes being expressed differently in the two cell types and try to understand what is causing that differential expression. They also plan to differentiate the iPS cells into various lineages to determine if the molecular signature is carried through to the mature cells. In their current study, Lowry and Plath did not look at differentiated cells, only the iPS and embryonic stem cells themselves.

Further study is crucial, said Mark Chin, a postdoctoral fellow and first author of the study.

“It will be important to further examine these cells lines in a careful and systematic manner, as has been done with other stem cell lines, if we are to understand the role they can play in clinical therapies and what effect the observed differences have on these cells,” he said.

 

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The stem cell center was launched in 2005 with a UCLA commitment of $20 million over five years. A $20 million gift from the Eli and Edythe Broad Foundation in 2007 resulted in the renaming of the center. With more than 150 members, the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research is committed to a multi-disciplinary, integrated collaboration of scientific, academic and medical disciplines for the purpose of understanding adult and human embryonic stem cells. The center supports innovation, excellence and the highest ethical standards focused on stem cell research with the intent of facilitating basic scientific inquiry directed towards future clinical applications to treat disease. The center is a collaboration of the David Geffen School of Medicine, UCLA’s Jonsson Cancer Center, the Henry Samueli School of Engineering and Applied Science and the UCLA College of Letters and Science. To learn more about the center, visit our web site at http://www.stemcell.ucla.edu.

Head below the fold for the second release on a call for an ethics debate on stem cells.

High efficiency polymer solar cells

The release:

UCLA researchers create polymer solar cells with higher efficiency levels

By

Wileen Wong Kromhout

| 11/26/2008

Currently, solar cells are difficult to handle, expensive to purchase and complicated to install. The hope is that consumers will one day be able to buy solar cells from their local hardware store and simply hang them like posters on a wall.

 

A new study by researchers at the UCLA Henry Samueli School of Engineering and Applied Science has shown that the dream is one step closer to reality. Reporting in the Nov. 26 edition of the Journal of the American Chemical Society, Yang Yang, a professor of materials science and engineering, and colleagues describe the design and synthesis of a new polymer, or plastic, for use in solar cells that has significantly greater sunlight absorption and conversion capabilities than previous polymers.

 

The research team found that substituting a silicon atom for carbon atom in the backbone of the polymer markedly improved the material’s photovoltaic properties. This silole-containing polymer can also be crystalline, giving it great potential as an ingredient for high-efficiency solar cells.

 

“With the reality of today’s energy crisis, a new-game changing technology is required to make solar cells more popular,” Yang said. “We hope that our newly synthesized polymer can eventually be used on solar cells far beyond their current rooftop applications. Imagine a house or car covered and powered by flexible solar films. Our dream is to see solar cells used everywhere.”

 

Polymers are lightweight, low-cost plastics used in packaging materials and inexpensive products like insulators, pipes, household products and toys. Polymer solar cells utilize organic compounds to produce electricity from sunlight. They are much cheaper to produce than traditional silicon-based solar cells and are also environmentally friendly.

 

But while polymer solar cells have been around for several years, their efficiency has, until recently, been low. The new polymer created by Yang’s team reached 5.1 percent efficiency in the published study but has in a few months improved to 5.6 percent in the lab. Yang and his team have proven that the photovoltaic material they use on their solar cells is one of the most efficient based on a single-layer, low-band-gap polymer.

 

At a lower band gap, the polymer solar cell can better utilize the solar spectrum, thereby absorbing more sunlight. At a higher band gap, light is not easily absorbed and can be wasted.

 

“Previously, the synthesizing process for the polymer was very complicated. We’ve been able to simplify the process and make it much easier to mass produce,” said Jianhui Hou, UCLA postdoctoral researcher and co-author of the study. “Though this is a milestone achievement, we will continue to work on improving the materials. Ideally we’d like to push the performance of the solar cell to higher than 10 percent efficiency. We know the potential is there.”

 

“We hope that solar cells will one day be as thin as paper and can be attached to the surface of your choice,” added co-author Hsiang-Yu Chen, a UCLA graduate student in engineering. “We’ll also be able to create different colors to match different applications.”

 

The study was funded by Solarmer Energy Inc. and a UC Discovery Grant. Solarmer Energy Inc. has recently licensed the technology from UCLA for commercialization.

 

The UCLA Henry Samueli School of Engineering and Applied Science, established in 1945, offers 28 academic and professional degree programs, including an interdepartmental graduate degree program in biomedical engineering. Ranked among the top 10 engineering schools at public universities nationwide, the school is home to six multimillion-dollar interdisciplinary research center in space exploration, wireless sensor systems, nanotechnology, nanomanufacturing and nanoelectronics, all funded by federal and private agencies. For more information, visit www.engineer.ucla.edu.

Aging 2008 dates announced

From KurzweilAI.net:

Methuselah Foundation Announces Aging 2008 at UCLA

KurzweilAI.net, May 19, 2008 On Friday June 27th, leading scientists and thinkers in stem cell research and regenerative medicine will gather in Los Angeles at UCLA for Aging 2008 to explain how their work can combat human aging, and the sociological implications of developing rejuvenation therapies. Aging 2008 is free, with advance registration required. Dr. Aubrey de Grey, chairman and chief science officer of the Methuselah Foundation, said “Our organization has raised over $10 million to crack open the logjams in longevity science. With the two-armed strategy of direct investments into key research projects, and a competitive prize to spur on scientists racing to break rejuvenation and longevity records in lab mice, the Foundation is actively accelerating the drive toward a future free of age-related degeneration.” The speakers at Aging 2008 will argue that the near-term consequences of intense research into regenerative medicine could be the development of therapies that extend healthy human life by decades, even if the therapies are applied in middle age. Peter Thiel, president of Clarium Capital, initial investor in Facebook, and lead sponsor of Aging 2008, said, “The time has come to challenge the inevitability of aging. This forum will provide an excellent opportunity to look at the scientific barriers that must be overcome to substantially extend healthy human life, as well as the ethical implications of doing so.” Aging 2008 also serves as the free opening session for the technically focused Understanding Aging Conference, which will run at UCLA on June 28th and 29th. What: Aging: The Disease, The Cure, The Implications, hosted by Methuselah Foundation When: Friday, June 27, 2008, Drinks 4pm, Presentations 5pm, Dinner 8pm Where: Royce Hall, 405 Hilgard Ave, Los Angeles, CA 90024 Who: * Dr. Bruce Ames, Professor of Biochemistry and Molecular Biology at UC Berkeley * G. Steven Burrill, Chairman of Pharmasset and Chairman of Campaign for Medical Research * Dr. Aubrey de Grey, Chairman and CSO of Methuselah Foundation and author of Ending Aging * Dr. William Haseltine, Chairman of Haseltine Global Health * Daniel Perry, Executive Director of Alliance for Aging Research * Bernard Siegel, Executive Director of Genetics Policy Institute * Dr. Gregory Stock, Director of Program on Medicine, Technology & Society at UCLA School of Medicine * Dr. Michael West, CEO of BioTime and Adjunct Professor of Bioengineering at UC Berkeley About Methuselah Foundation The Methuselah Foundation is a 501(c)(3) nonprofit organization dedicated to extending the healthy human lifespan. Founded in 2002 by entrepreneur David Gobel and gerontologist Dr. Aubrey de Grey, the Methuselah Foundation funds two major projects: The Mprize, a multimillion dollar research prize, and SENS, a detailed engineering plan to repair aging-related damage. Learn more at http://mfoundation.org.

Nanotech news in computing, display and medicine

The latest in nanotechnology developments from KurzweilAI.net.

First up is a variant of multidimensional hypercubes to be used as part of nanocomputers.

Next is an active-matrix display created with nanowires. This tech should eventually lead to e-paper, flexible monitors and other cool display applications.

Last is a nanomachine that kills cancer cells. UCLA researchers created a “nanoimpeller” that delivers anti-cancer drugs right to the cancer cell.

Hypercubes Could Be Building Blocks of Nanocomputers

PhysOrg.com, April 1, 2008University of Oklahoma researchers have investigated a new variant of multidimensional hypercubes as computational elements of nanocomputers: the “M-hypercube,” which could provide a higher-dimensional layout to support three-dimensional integrated circuits and the quantum properties of nanocomputers.The unique structure of hypercubes provides a massively parallel, distributed processing architecture with simple, robust communication linkages, able to count single electrons, and allow for parallel computing, reversibility, locality, and a three-dimensional architecture. M-hypercubes contain two types of nodes: state nodes, which are embedded on the vertices of the M-hypercubes; and transmission nodes, which are embedded in the middle of the links between state nodes. Each node can be turned on or off; the transmission nodes can isolate parts of the cube from other parts when in the off state. Read Original Article>>

Engineers make first ‘active matrix’ display using nanowires

PhysOrg.com, March 31, 2008Purdue University researchers have created the first active-matrix display using a new class of transparent nanowire transistors and circuits.Future applications include e-paper, flexible color monitors, and heads-up displays embedded in car windshields. Read Original Article>>

Nanomachine kills cancer cells

PhysOrg.com, April 1, 2008UCLA researchers have developed a “nanoimpeller” nanomachine that stores anticancer drugs inside pores and then releases them into cancer cells in response to light.They claim it’s the first light-powered nanomachine that operates inside a living cell. The interior of the pores are coated with azobenzene, a chemical that oscillates between two different shapes upon light exposure. The amount of drug released can be precisely controlled by the light‘s intensity, excitation time and specific wavelength. Read Original Article>>