David Kirkpatrick

November 4, 2010

Transparent solar panels?

A very real possibility. This sounds like very promising technology.

The release:

Transparent Conductive Material Could Lead to Power-Generating Windows

Combines elements for light harvesting and electric charge transport over large, transparent areas

November 3, 2010

conjugated polymer honeycombClick on the image to download a high-resolution version.Top: Scanning electron microscopy image and zoom of conjugated polymer (PPV) honeycomb. Bottom (left-to-right): Confocal fluorescence lifetime images of conjugated honeycomb, of polymer/fullerene honeycomb double layer and of polymer/fullerene honeycomb blend. Efficient charge transfer within the whole framework is observed in the case of polymer/fullerene honeycomb blend as a dramatic reduction in the fluorescence lifetime.

UPTON, NY — Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Los Alamos National Laboratory have fabricated transparent thin films capable of absorbing light and generating electric charge over a relatively large area. The material, described in the journal Chemistry of Materials, could be used to develop transparent solar panels or even windows that absorb solar energy to generate electricity.

The material consists of a semiconducting polymer doped with carbon-rich fullerenes. Under carefully controlled conditions, the material self-assembles to form a reproducible pattern of micron-size hexagon-shaped cells over a relatively large area (up to several millimeters).

“Though such honeycomb-patterned thin films have previously been made using conventional polymers like polystyrene, this is the first report of such a material that blends semiconductors and fullerenes to absorb light and efficiently generate charge and charge separation,” said lead scientist Mircea Cotlet, a physical chemist at Brookhaven’s Center for Functional Nanomaterials (CFN).

Furthermore, the material remains largely transparent because the polymer chains pack densely only at the edges of the hexagons, while remaining loosely packed and spread very thin across the centers. “The densely packed edges strongly absorb light and may also facilitate conducting electricity,” Cotlet explained, “while the centers do not absorb much light and are relatively transparent.”

Mircea CotletClick on the image to download a high-resolution version.Mircea Cotlet, Ranjith Krishna Pai, and Zhihua Xu (seated at the microscope).

“Combining these traits and achieving large-scale patterning could enable a wide range of practical applications, such as energy-generating solar windows, transparent solar panels, and new kinds of optical displays,” said co-author Zhihua Xu, a materials scientist at the CFN.

“Imagine a house with windows made of this kind of material, which, combined with a solar roof, would cut its electricity costs significantly. This is pretty exciting,” Cotlet said.

The scientists fabricated the honeycomb thin films by creating a flow of micrometer-size water droplets across a thin layer of the polymer/fullerene blend solution. These water droplets self-assembled into large arrays within the polymer solution. As the solvent completely evaporates, the polymer forms a hexagonal honeycomb pattern over a large area.

“This is a cost-effective method, with potential to be scaled up from the laboratory to industrial-scale production,” Xu said.

The scientists verified the uniformity of the honeycomb structure with various scanning probe and electron microscopy techniques, and tested the optical properties and charge generation at various parts of the honeycomb structure (edges, centers, and nodes where individual cells connect) using time-resolved confocal fluorescence microscopy.

The scientists also found that the degree of polymer packing was determined by the rate of solvent evaporation, which in turn determines the rate of charge transport through the material.

“The slower the solvent evaporates, the more tightly packed the polymer, and the better the charge transport,” Cotlet said.

“Our work provides a deeper understanding of the optical properties of the honeycomb structure. The next step will be to use these honeycomb thin films to fabricate transparent and flexible organic solar cells and other devices,” he said.

The research was supported at Los Alamos by the DOE Office of Science. The work was also carried out in part at the CFN and the Center for Integrated Nanotechnologies Gateway to Los Alamos facility. The Brookhaven team included Mircea Cotlet, Zhihua Xu, and Ranjith Krishna Pai. Collaborators from Los Alamos include Hsing-Lin Wang and Hsinhan Tsai, who are both users of the CFN facilities at Brookhaven, Andrew Dattelbaum from the Center for Integrated Nanotechnologies Gateway to Los Alamos facility, and project leader Andrew Shreve of the Materials Physics and Applications Division.

The Center for Functional Nanomaterials at Brookhaven National Laboratory and the Center for Integrated Nanotechnologies Gateway to Los Alamos facility are two of the five DOE Nanoscale Science Research Centers (NSRCs), premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories.


April 3, 2010

Growing and testing graphene

Filed under: Science — Tags: , , , , — David Kirkpatrick @ 4:49 pm

Doing some science on the once and future miracle material. I’m not holding my breath, but if graphene manages to reach fifty percent of its hype, it’s going to change the world. It’s that hyped, and it truly has that much promise.

From the link:

“We found that if a single graphene sheet is grown on a metal like ruthenium, the metal binds very strongly to the  and disrupts the characteristic properties normally found in isolated graphene,” Sutter said. “But those properties re-emerge in subsequent layers grown on the substrate.”

In other words, the first graphene layer grown on  satiates the metal substrate, allowing the rest of the layers to reclaim their normal properties.

“As a result of this growth process, a two-layer stack acts like an isolated monolayer of graphene and a three-layer stack acts like an isolated bilayer,” Sutter said.

The findings of the group, which also includes Brookhaven researchers Mark Hybertsen, Jurek Sadowski, and Eli Sutter, lays groundwork for future graphene production for advanced technologies, and helps researchers understand how metals — for example in device contacts — change the properties of .

March 31, 2009

DNA as nanoparticle assembly plant

More forward motion in the world of nanotech.

The release:

DNA-based assembly line for precision nano-cluster construction

Method could lead to rapid, reliable assembly of new biosensors and solar cells

UPTON, NY – Building on the idea of using DNA to link up nanoparticles – particles measuring mere billionths of a meter – scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have designed a molecular assembly line for predictable, high-precision nano-construction. Such reliable, reproducible nanofabrication is essential for exploiting the unique properties of nanoparticles in applications such as biological sensors and devices for converting sunlight to electricity. The work will be published online March 29, 2009, by Nature Materials.

The Brookhaven team has previously used DNA, the molecule that carries life’s genetic code, to link up nanoparticles in various arrangements, including 3-D nano-crystals. The idea is that nanoparticles coated with complementary strands of DNA – segments of genetic code sequence that bind only with one another like highly specific Velcro – help the nanoparticles find and stick to one another in highly specific ways. By varying the use of complementary DNA and strands that don’t match, scientists can exert precision control over the attractive and repulsive forces between the nanoparticles to achieve the desired construction. Note that the short DNA linker strands used in these studies were constructed artificially in the laboratory and don’t “code” for any proteins, as genes do.

The latest advance has been to use the DNA linkers to attach some of the DNA-coated nanoparticles to a solid surface to further constrain and control how the nanoparticles can link up. This yields even greater precision, and therefore a more predictable, reproducible high-throughput construction technique for building clusters from nanoparticles.

“When a particle is attached to a support surface, it cannot react with other molecules or particles in the same way as a free-floating particle,” explained Brookhaven physicist Oleg Gang, who led the research at the Lab’s Center for Functional Nanomaterials. This is because the support surface blocks about half of the particle’s reactive surface. Attaching a DNA linker or other particle that specifically interacts with the bound particle then allows for the rational assembly of desired particle clusters.

“By controlling the number of DNA linkers and their length, we can regulate interparticle distances and a cluster’s architecture,” said Gang. “Together with the high specificity of DNA interactions, this surface-anchored technique permits precise assembly of nano-objects into more complex structures.”

Instead of assembling millions and millions of nanoparticles into 3-D nanocrystals, as was done in the previous work, this technique allows the assembly of much smaller structures from individual particles. In the Nature Materials paper, the scientists describe the details for producing symmetrical, two-particle linkages, known as dimers, as well as small, asymmetrical clusters of particles – both with high yields and low levels of other, unwanted assemblies.

“When we arrange a few nanoparticles in a particular structure, new properties can emerge,” Gang emphasized. “Nanoparticles in this case are analogous to atoms, which, when connected in a molecule, often exhibit properties not found in the individual atoms. Our approach allows for rational and efficient assembly of nano-‘molecules.’ The properties of these new materials may be advantageous for many potential applications.”

For example, in the paper, the scientists describe an optical effect that occurs when nanoparticles are linked as dimer clusters. When an electromagnetic field interacts with the metallic particles, it induces a collective oscillation of the material’s conductive electrons. This phenomenon, known as a plasmon resonance, leads to strong absorption of light at a specific wavelength.

“The size and distance between the linked particles affect the plasmonic behavior,” said Gang. By adjusting these parameters, scientists might engineer clusters for absorbing a range of wavelengths in solar-energy conversion devices. Modulations in the plasmonic response could also be useful as a new means for transferring data, or as a signal for a new class of highly specific biosensors.

Asymmetric clusters, which were also assembled by the Brookhaven team, allow an even higher level of control, and therefore open new ways to design and engineer functional nanomaterials.




Because of its reliability and precision control, Brookhaven’s nano-assembly method would be scalable for the kind of high-throughput production that would be essential for commercial applications. Brookhaven Lab has applied for a patent on the assembly method as well as several specific applications of the technology. For information about the patent or licensing this technology, contact Kimberley Elcess at (631) 344-4151, or elcess@bnl.gov.

In addition to Gang, the team included materials scientist Dmytro Nykypanchuk, summer student Marine Cuisinier, and biologist Daniel (Niels) van der Lelie, all from Brookhaven, and former Brookhaven chemist Matthew Maye, now at Syracuse University. Their work was funded by DOE’s Office of Science and through a Goldhaber Distinguished Fellowship sponsored by Brookhaven Science Associates.

The Center for Functional Nanomaterials at BNL is one of the five DOE Nanoscale Science Research Centers (NSRCs), premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize, and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Brookhaven, Argonne, Lawrence Berkeley, Oak Ridge, and Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit http://nano.energy.gov.

Related Links

DNA Technique Yields 3-D Crystalline Organization of Nanoparticles, 1/30/2008:

New DNA-Based Technique For Assembly of Nano- and Micro-sized Particles, 9/12/2007:

Nanoparticle Assembly Enters the Fast Lane, 10/11/2006:

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation of State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

Visit Brookhaven Lab’s electronic newsroom for links, news archives, graphics, and more: http://www.bnl.gov/newsroom

Update — Here’s this topic from KurzweilAI.net:

DNA-Based Assembly Line for Nano-Construction of New Biosensors, Solar Cells (w/Video)

PhysOrg.com, Mar. 30, 2009

A molecular assembly line using DNA linkers for predictable, high-precision nano-construction has been developed by scientists at the U.S. Department of Energy‘s Brookhaven National Laboratory.

Read Original Article>>


July 11, 2008

A whole slew of nanotechnology news

In a departure from the usual format, here’s a roundup of nanotech news from the last two days of KurzweilAI.net’s e-newsletter. There’s so much here these bits are taken straight from the email.

Controlling the Size of
Nanoclusters: First Step in Making
New Catalysts
KurzweilAI.net July 10, 2008
Researchers from the U.S.
Department of Energy’s (DOE)
Brookhaven National Laboratory and
Stony Brook University have
developed a new instrument that
allows them to control the size of
nanoclusters — groups of 10 to 100
atoms — with atomic precision. The
device could allow for making
nanoclusters with predetermined
size, structure and…

Nanotubes Hold Promise for
Next-Generation Computing
Wired July 9, 2008
Two groups of researchers have
recently published papers
demonstrating advances in creating,
sorting and organizing carbon
nanotubes so they can be used in
electronics. Stanford electrical
engineers addressed the problem of
getting nanotubes straightened out
so they could be put to work in
chips, by growing the nanotubes on
crystalline quartz,…

Assembling Nanotubes
Technology Review July 10, 2008
Stanford University and Samsung
Advanced Institute of Technology
researchers have developed a new
method for sorting single-walled
carbon nanotubes by electronic type
and arranging them over a large
area; it could be useful for
manufacturing high-performance
displays and other electronic
devices. (Melburne LeMieux /
Stanford University)…

Nanotubes bring artificial
photosynthesis a step nearer
New Scientist news service July 11, 2008
Carbon nanotubes are the crucial
chemical ingredient that could make
artificial photosynthesis possible,
say Chinese researchers. Artificial
photosynthesis could efficiently
produce hydrogen that could be used
as a clean fuel and also mop up
carbon dioxide from the atmosphere.
By covalently bonding a large number
of phthalocyanine molecules…

April 4, 2008

Red pill or blue pill?

Filed under: Technology — Tags: , , , — David Kirkpatrick @ 2:08 pm

From KurzweilAI.net:

Matrix-style virtual worlds ‘a few years away’
New Scientist news service, April 3, 2008Are supercomputers on the verge of creating Matrix-style simulated realities?

Michael McGuigan at Brookhaven National Laboratory thinks so, and has used the Lab’s Blue Gene/L supercomputer to generate a photorealistic, real-time artificial world. He found that conventional ray-tracing software could run 822 times faster on the Blue Gene/L than on a standard computer, allowing it to convincingly mimic natural lighting in real time.

The ultimate objective is to pass the “Graphics Turing Test,” in which a human judge viewing and interacting with an artificially generated world should be unable to reliably distinguish it from reality.

He believes that should be possible in the next few years, once supercomputers enter the petaflop range, along with parallel computing.
Read Original Article>>

March 5, 2008

Lots of cool science and tech …

… from today’s KurzweilAI.net newsletter. The first two are bits about solar energy — the first on even “greener” solar panels, and the second on inkjet printing organic solar cells.

The third story is on cancer and embryonic stem cells. I look forward to the day the US government no longer bans federal funding of this research. I’m all for private research, but the fact is medical research in the US is pretty much handled through the NIH.

Here’s all three:

Greener Green Energy: Today’s solar cells give more than they take
Science News, March 1, 2008Solar power produces, per unit of energy, only about one-tenth as much carbondioxide and other harmful emissions (during manufacturing) as does conventional power generation, a new study by Brookhaven National Laboratory scientists shows.

These improvements in efficiency mean that today’s solar panels can “pay back” in only 1 to 3 years the energy needed to make them, the study concludes.

Improvements in manufacturing efficiency could reduce emissions from solar power by another 50 percent within 5 to 7 years, the researchers say.
Read Original Article>>

Konarka Announces First-Ever Demonstration of Inkjet Printed Solar Cells
nanowerk, Mar. 3, 2008Konarka Technologies has announced the company conducted the first-ever demonstration of manufacturing organic solar cells by efficient inkjet printing.

Read Original Article>>

Cancers inhibited by embryonic stem cell protein
NewScientist.com news service, March 4, 2008Northwestern University researchers have discovered that a protein, Lefty, produced by human embryonic stem cells (hESCs) can inhibit the growth and spread of breast cancer and malignant melanoma.

Similarities between stem cells and tumors–both are self-renewing and have the capacity to give rise to different cells types–previously led the researchers to find the protein Nodal, which facilitates cell growth, and suggested that stem cells must have a way to control Nodal.

The Northwestern researchers found that was Lefty. When aggressive tumor cells were exposed to the chemical environment of hESCs, which contained Lefty, their Nodal production fell sharply, and the tumor cells became less invasive and even started to die.
Read Original Article>>