David Kirkpatrick

March 18, 2010


Sounds like this would make a trip to the grocery store a snap. These tags are based on a carbon-nanotube-infused ink for ink-jet printers.

Rice researchers, in collaboration with a team led by Gyou-jin Cho at Sunchon National University in Korea, have come up with an inexpensive, printable transmitter that can be invisibly embedded in packaging. It would allow a customer to walk a cart full of groceries or other goods past a scanner on the way to the car; the scanner would read all items in the cart at once, total them up and charge the customer’s account while adjusting the store’s inventory.

More advanced versions could collect all the information about the contents of a store in an instant, letting a retailer know where every package is at any time.

RFID tags printed through a new roll-to-roll process could replace bar codes and make checking out of a store a snap. Credit: Gyou-Jin Cho/Sunchon National University

May 1, 2009

Nanotubes seeing the rainbow

Nanotubes that can “see” the entire spectrum offer a lot of possibilities in terms of application, including improved solar cells.

The release:

Sandia researchers construct carbon nanotube device that can detect colors of the rainbow

LIVERMORE, Calif. — Researchers at Sandia National Laboratories have created the first carbon nanotube device that can detect the entire visible spectrum of light, a feat that could soon allow scientists to probe single molecule transformations, study how those molecules respond to light, observe how the molecules change shapes, and understand other fundamental interactions between molecules and nanotubes.

Carbon nanotubes are long thin cylinders composed entirely of carbon atoms. While their diameters are in the nanometer range (1-10), they can be very long, up to centimeters in length.

The carbon-carbon bond is very strong, making carbon nanotubes very robust and resistant to any kind of deformation. To construct a nanoscale color detector, Sandia researchers took inspiration from the human eye, and in a sense, improved on the model.

When light strikes the retina, it initiates a cascade of chemical and electrical impulses that ultimately trigger nerve impulses. In the nanoscale color detector, light strikes a chromophore and causes a conformational change in the molecule, which in turn causes a threshold shift on a transistor made from a single-walled carbon nanotube.

“In our eyes the neuron is in front of the retinal molecule, so the light has to transmit through the neuron to hit the molecule,” says Sandia researcher Xinjian Zhou. “We placed the nanotube transistor behind the molecule—a more efficient design.”

Zhou and his Sandia colleagues François Léonard, Andy Vance, Karen Krafcik, Tom Zifer, and Bryan Wong created the device. The team recently published a paper, “Color Detection Using Chromophore-Nanotube Hybrid Devices,” in the journal Nano Letters.

The idea of carbon nanotubes being light sensitive has been around for a long time, but earlier efforts using an individual nanotube were only able to detect light in narrow wavelength ranges at laser intensities. The Sandia team found that their nanodetector was orders of magnitude more sensitive, down to about 40 W/m2—about 3 percent of the density of sunshine reaching the ground. “Because the dye is so close to the nanotube, a little change turns into a big signal on the device,” says Zhou.

The research is in its second year of internal Sandia funding and is based on Léonard’s collaboration with the University of Wisconsin to explain the theoretical mechanism of carbon nanotube light detection. Léonard literally wrote the book on carbon nanotubes—The Physics of Carbon Nanotubes, published September 2008.

Léonard says the project draws upon Sandia’s expertise in both materials physics and materials chemistry. He and Wong laid the groundwork with their theoretical research, with Wong completing the first-principles calculations that supported the hypothesis of how the chromophores were arranged on the nanotubes and how the chromophore isomerizations affected electronic properties of the devices.

To construct the device, Zhou and Krafcik first had to create a tiny transistor made from a single carbon nanotube. They deposited carbon nanotubes on a silicon wafer and then used photolithography to define electrical patterns to make contacts.

The final piece came from Vance and Zifer, who synthesized molecules to create three types of chromophores that respond to either the red, green, or orange bands of the visible spectrum. Zhou immersed the wafer in the dye solution and waited a few minutes while the chromophores attached themselves to the nanotubes.

The team reached their goal of detecting visible light faster than they expected—they thought the entire first year of the project would be spent testing UV light. Now, they are looking to increase the efficiency by creating a device with multiple nanotubes.

“Detection is now limited to about 3 percent of sunlight, which isn’t bad compared with a commercially available digital camera,” says Zhou. “I hope to add some antennas to increase light absorption.”

A device made with multiple carbon nanotubes would be easier to construct and the resulting larger area would be more sensitive to light. A larger size is also more practical for applications.

Now, they are setting their sites on detecting infrared light. “We think this principle can be applied to infrared light and there is a lot of interest in infrared detection,” says Vance. “So we’re in the process of looking for dyes that work in infrared.”

This research eventually could be used for a number of exciting applications, such as an optical detector with nanometer scale resolution, ultra-tiny digital cameras, solar cells with more light absorption capability, or even genome sequencing. The near-term purpose, however, is basic science.

“A large part of why we are doing this is not to invent a photo detector, but to understand the processes involved in controlling carbon nanotube devices,” says Léonard.

The next step in the project is to create a nanometer-scale photovoltaic device. Such a device on a larger scale could be used as an unpowered photo detector or for solar energy. “Instead of monitoring current changes, we’d actually generate current,” says Vance. “We have an idea of how to do it, but it will be a more challenging fabrication process.”

Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

February 6, 2009

Synaesthesia and cheaper fuel cells through nanotech

Filed under: Science, Technology — Tags: , , , , , — David Kirkpatrick @ 4:40 pm

From KurzweilAI.net — I’m going old school (old school for this blog) today with post containing multiple bits from today’s KurzweilAI e-newsletter.

First up is a story on the genetic roots of synaesthesia — the condition of seeing sounds and tasting colors and other mixed up signals from the five senses. The second is on carbon nanotubes making fuel cells more cheap and longer lasting.

Genetic roots of synaesthesia unearthed
New Scientist Health, Feb. 5, 2009

The regions of our DNA that wire some people to “see” sounds have been discovered. So far, only the general regions within chromosomes have been identified, rather than specific genes, but the work could eventually lead to a genetic test to diagnose the condition before it interferes with a child’s education.
Read Original Article>>

Cheaper Fuel Cells
Technology Review, Feb. 5, 2009

University of Dayton researchers have shown that arrays of vertically grown carbon nanotubes could be used as the catalyst in fuel cells.


The carbon nanotubes, which are doped with nitrogen, would be much cheaper and longer lasting than the expensive platinum catalysts used now, with four times higher current densities.

Read Original Article>>

January 23, 2009

Carbon nanotube electronics hit the market

Filed under: Business, Science, Technology — Tags: , , , , , — David Kirkpatrick @ 12:39 am

Very exciting news here. A transparent plastic product with a carbon nanotube coating will be the first electronic nanotube product to hit the market. Lots of promising applications with this product.

From the link:

The first electronic product using carbon nanotubes is slated to hit the market this year. Unidym, a startup based in Menlo Park, CA, plans to start selling rolls of its carbon-nanotube-coated plastic films in the second half of 2009.

The transparent, conductive films could make manufacturing LCD screens faster and cheaper. They could enhance the life of touch panels used in ATM screens and supermarket kiosks. They might also pave the way for flexible thin-film solar cells and bright, roll-up color displays. The displays could be used in cell phones, billboards, and electronic books and magazines.

In all of these applications, the nanotube sheets would replace the indium tin oxide (ITO) coatings that are currently used as transparent electrodes. ITO cracks easily and is a more expensive material. “The cost of indium has gone up by 100 times in the last 10 years,” says Peter Harrop, chairman of IDTechEx, a research and consulting firm based in Cambridge, U.K.


Nanotube shrink-wrap: A small sample of the carbon-nanotube-coated plastic film that could be used as the see-through electrodes in touch screens, roll-up displays, and thin-film solar cells. Credit: Unidym

August 12, 2008

Nanotubes improve brain readouts

Nanotechnology is really making strides in medicine, particularly in cancer treatment (find links to my most recent three nanotech/cancer posts here, here and here)

This breakthrough is a little different and involves coating metal neural electrodes with carbon nanotubes.

Here’s an excerpt from the PhysOrg.com article:

Keefer compared the improvement in nanotube-coated electrodes over standard electrodes to the difference between watching your favorite show on a 13-inch black-and-white television with a broken antenna or a brand-new 60-inch, high-definition, satellite-fed model.

“For an electrophysiologist, that is the difference the nanotube-coated electrodes make in what we can see on our oscilloscopes,” he said.

The electrodes they tested were commercial varieties made of tungsten and stainless steel wire, which are thin and sharp. In two animal samples—the motor cortex of rats under anaesthesia and the visual cortex of awake rhesus macaque monkeys—the group took readouts with a nanotube-coated electrode and a non-coated electrode, and compared the results.

In both cases, the coated electrodes produced much better readings. The performance was further enhanced when the group used a coating made of a combination of carbon nanotubes and a conducting polymer material.

Additionally, scanning electron microscope images showed that the coating on the electrodes used for the monkeys had not been damaged by the tough outer brain layer, called the dura mater.

Besides performance, the coated electrodes have other advantages. Scientists have already documented the properties and performance of metal-coated electrodes used in other applications, such as electronics, and nanotubes appear to be nicely biocompatible. For example, scientists have had success using carbon nanotube substrates as supports for the growth of neurons.

April 16, 2008

World’s first thermal nanomotor

Filed under: Science, Technology — Tags: , , , , — David Kirkpatrick @ 2:35 pm

The release:

Researchers create the first thermal nanomotor in the world

The motor functions as a nanotransporter by moving and rotating cargo from one end of the carbon nanotube to the other

This release is available in Spanish.

Researchers from the UAB Research Park have created the first nanomotor that is propelled by changes in temperature. A carbon nanotube is capable of transporting cargo and rotating like a conventional motor, but is a million times smaller than the head of a needle. This research opens the door to the creation of new nanometric devices designed to carry out mechanical tasks and which could be applied to the fields of biomedicine or new materials.

The “nanotransporter” consists of a carbon nanotube – a cylindrical molecule formed by carbon atoms – covered with a shorter concentric nanotube which can move back and forth or act as a rotor. A metal cargo can be added to the shorter mobile tube, which could then transport this cargo from one end to the other of the longer nanotube or rotate around its axis.

Researchers are able to control these movements by applying different temperatures at the two ends of the long nanotube. The shorter tube thus moves from the warmer to the colder area and is similar to how air moves around a heater. This is the first time a nanoscale motor is created that can use changes in temperature to generate and control movements.

The movements along the longer tube can be controlled with a precision of less than the diameter of an atom. This ability to control objects at nanometre scale can be extremely useful for future applications in nanotechnology, e.g. in designing nanoelectromechanical systems with great technological potential in the fields in biomedicine and new materials.




The research has been published in the online journal Science Express (www.sciencexpress.org) and was directed by Adrian Bachtold, researcher at CIN2 (Nanoscience and Nanotechnology Research Centre, CSIC-ICN) and at CNM (National Microelectronics Centre, CSIC), and by Eduardo Hernández at ICMAB (Institute of Material Science, CSIC), all of which form part of the UAB Research Park. Research members included Riccardo Rurali from the UAB Department of Electronic Engineering, and Amelia Barreiro and Joel Moser from CIN2 (CSIC-ICN), with the collaboration of researchers from the University of Vienna, Austria and from EPFL in Lausanne, Switzerland.

The Catalan Institute of Nanotechnology is a private foundation publicly funded by the Catalan Government and Universitat Autònoma de Barcelona. The Nanoscience and Nanotechnology Research Centre is run jointly by the Spanish National Research Council and the Catalan Institute of Nanotechnology. The National Microelectronics Centre (CNM) and the Institute of Material Sciences (ICMAB) both belong to the Spanish National Research Council. The UAB Research Park – a joint alliance between UAB, CSIC and IRTA (Institute for Food and Agricultural Research and Technology) – is formed by a group of research centres and consortiums located at the Bellaterra campus of Universitat Autònoma de Barcelona.

(Hat tip: KurzweilAI.net)

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