#One step closer to a single-molecule device: Columbia Engineering researchers first to create a single-molecule diode--the ultimate in miniaturization for electronic devices--with potential for real-world applications Under the direction of Latha Venkataraman, associate professor of applied physics at Columbia Engineering,
researchers have designed a new technique to create a single-molecule diode, and, in doing so, they have developed molecular diodes that perform 50 times better than all prior designs.
Venkataraman's group is the first to develop a single-molecule diode that may have real-world technological applications for nanoscale devices.
Their paper,"Single-Molecule Diodes with High On-Off Ratios through Environmental Control""is published May 25 in Nature Nanotechnology."
"Our new approach created a single-molecule diode that has a high(>250) rectification and a high"on"current (0. 1 micro Amps),"says Venkataraman."
"Constructing a device where the active elements are only a single molecule has long been a tantalizing dream in nanoscience.
This goal, which has been the'holy grail'of molecular electronics ever since its inception with Aviram and Ratner's 1974 seminal paper, represents the ultimate in functional miniaturization that can be achieved for an electronic device."
"With electronic devices becoming smaller every day, the field of molecular electronics has become ever more critical in solving the problem of further miniaturization,
and single molecules represent the limit of miniaturization. The idea of creating a single-molecule diode was suggested by Arieh Aviram
and Mark Ratner who theorized in 1974 that a molecule could act as a rectifier, a one-way conductor of electric current.
Researchers have since been exploring the charge-transport properties of molecules. They have shown that single-molecules attached to metal electrodes (single-molecule junctions) can be made to act as a variety of circuit elements
including resistors, switches, transistors, and, indeed, diodes. They have learned that it is possible to see quantum mechanical effects, such as interference, manifest in the conductance properties of molecular junctions.
Since a diode acts as an electricity valve, its structure needs to be asymmetric so that electricity flowing in one direction experiences a different environment than electricity flowing in the other direction.
In order to develop a single-molecule diode, researchers have designed simply molecules that have asymmetric structures.""While such asymmetric molecules do indeed display some diode-like properties,
they are not effective, "explains Brian Capozzi, a Phd student working with Venkataraman and lead author of the paper."
"A well-designed diode should only allow current to flow in one direction--the'on'direction
--and it should allow a lot of current to flow in that direction. Asymmetric molecular designs have suffered typically from very low current flow in both'on and off'directions,
and the ratio of current flow in the two has typically been low. Ideally, the ratio of'on'current to'off'current, the rectification ratio, should be very high."
"In order to overcome the issues associated with asymmetric molecular design, Venkataraman and her colleagues--Chemistry Assistant professor Luis Campos'group at Columbia and Jeffrey Neaton's group at the Molecular Foundry at UC Berkeley--focused on developing an asymmetry in the environment around the molecular junction.
They created an environmental asymmetry through a rather simple method--they surrounded the active molecule with an ionic solution
and used gold metal electrodes of different sizes to contact the molecule. Their results achieved rectification ratios as high as 250: 50 times higher than earlier designs.
The"on"current flow in their devices can be more than 0. 1 microamps which, Venkataraman notes, is a lot of current to be passing through a single-molecule.
And, because this new technique is implemented so easily, it can be applied to all nanoscale devices of all types,
including those that are made with graphene electrodes.""It's amazing to be able to design a molecular circuit,
using concepts from chemistry and physics, and have it do something functional, "Venkataraman says.""The length scale is so small that quantum mechanical effects are absolutely a crucial aspect of the device.
So it is truly a triumph to be able to create something that you will never be able to physically see
and that behaves as intended.""She and her team are now working on understanding the fundamental physics behind their discovery,
and trying to increase the rectification ratios they observed, using new molecular systems s
#Fine-tuned molecular orientation is key to more efficient solar cells Polymer-based solar cells offer a number of potential advantages.
They are made of polymers that are inexpensive and flexible, and can be deposited on glass or plastic substrates, allowing the construction of large-scale structures.
They are cheaper to manufacture, and more environmentally-friendly, than their silicon counterparts. Unfortunately, they have lower power efficiency due to their structure
and Kazuo Takimiya of the RIKEN Center for Emergent Matter Science managed to create a type of polymer solar cell called a bulk-heterojunction solar cellhere the electron donor
and were able initially to achieve a power conversion efficiency of about 8%,with a fairly thick active layer of about 300 nanometers.
where the light enters through a transparent negative electrode, in our case made of zinc oxide,
we found that the cell with the inverted architecture had better efficiency, which is abnormal for cells of the type we built.
According to Professor Hideyuki Murata of the Japan Advanced Institute of Science and Technology who participated in the research,
because we now have an understanding of how we can move forward to create polymer solar cells with greater efficiency.
The work was done in collaboration with the Japan Advanced Institute of Science and Technology, Hiroshima University,
Non-aqueous solvent supports DNA NANOTECHNOLOGY Abstract: Scientists around the world are using the programmability of DNA to assemble complex nanometer scale structures.
Until now, however, production of these artificial structures has been limited to water-based environments, because DNA naturally functions inside the watery environment of living cells.
Researchers at the Georgia Institute of technology have shown now that they can assemble DNA NANOSTRUCTURES in a solvent containing no water.
They also discovered that adding a small amount of water to their solvent increases the assembly rate
and provides a new means for controlling the process. The solvent may also facilitate the production of more complex structures by reducing the problem of DNA becoming trapped in unintended structures.
The research could open up new applications for DNA NANOTECHNOLOGY and help apply DNA technology to the fabrication of nanoscale semiconductor and plasmonic structures.
Sponsored by the National Science Foundation and NASA, the research will be published as the cover story in Issue 23 of the journal Angewandte Chemie International Edition.
NA nanotechnology structures are getting more and more complex, and this solvent could help researchers that are working in this growing field,
said Nicholas Hud, a professor in Georgia Tech School of Chemistry and Biochemistry. ith this work,
we have shown that DNA NANOSTRUCTURES can be assembled in a water-free solvent, and that we can mix water with the same solvent to speed up the assembly.
The assembly rate of DNA NANOSTRUCTURES can be very slow, and depends strongly on temperature. Raising the temperature increases this rate,
This solvent also offers enhanced properties for nanotechnology and for the stability of these nanomaterials in solution.
Gállego had worked in DNA NANOTECHNOLOGY before coming to Georgia Tech, and was convinced that alternative solvents could advance this field.
At Georgia Tech he evaluated new solvents for use with DNA NANOSTRUCTURES, solvents that had been designed for other purposes.
Structures that fail to completely assemble are a major source of low yields in the DNA nanofabrication process. his solvent could provide a new tool to make more complicated designs with DNA
he added. inetic traps are among the bottlenecks for producing more complicated DNA NANOSTRUCTURES. Glycholine is miscible in water
A key feature of the new solvent system is that it does not require changes to existing DNA NANOTECHNOLOGY designs that were developed for water. ou can go back
said Gállego. his solvent system preserves the DNA structures that have been developed to work in water.
The solvent system could improve the combined use of metallic nanoparticles and DNA based materials. In the typical aqueous solvents where DNA NANOTECHNOLOGY is performed
nanoparticles are prone to aggregation. The solvent low volatility could also allow storage of assembled DNA structures without the concern that a water-based medium would dry out.
The research team, which also included Martha Grover from Georgia Tech School of Chemical & Biomolecular engineering, has used so far the solvent to assemble three structures,
including two DNA origami structures. In future work, they hope to use the control provided by water-free solvents to obtain dynamic DNA structural rearrangements that are not possible in water,
and investigate other solvents that may have additional properties attractive for nanotechnology applications. e were confident all along that we would find a solvent that would be compatible with existing DNA NANOTECHNOLOGY,
added Hud, who is also director of the NSF-NASA Center for Chemical Evolution and associate director of the Parker H. Petit Institute of Bioengineering and Bioscience,
both at Georgia Tech. hat was surprising was finding a solvent that allows the assembly of structures more easily than in water.
because DNA NANOTECHNOLOGY was developed in water. The research on water-free solvents grew out of Georgia Tech research into the origins of life.
the chemistry necessary to make the molecules of life would be much easier without water being present. his work was inspired by research into the origins of life with the basic question of
while also having applications in nanotechnology. This research was supported by the National Science Foundation (NSF) and the NASA Astrobiology Program under the NSF Center for Chemical Evolution (CHE-1004570.
#Nanotechnology identifies brain tumor types through MRI'virtual biopsy'in animal studies: If results are confirmed in humans,
tumor cells could someday be diagnosed by MRI imaging and treated with tumor-specific IV injections;
new NIH grant will fund future study Abstract: Biomedical researchers at Cedars-Sinai have invented a tiny drug-delivery system that can identify cancer cell types in the brain through"virtual biopsies
"and then attack the molecular structure of the disease. If laboratory research with mice is borne out in human studies,
the results could be used to deliver nanoscale drugs that can distinguish and fight tumor cells in the brain without resorting to surgery."
"Our nanodrug can be engineered to carry a variety of drugs, proteins and genetic materials to attack tumors on several fronts from within the brain,"said Julia Ljubimova, MD, Phd,
professor of neurosurgery and biomedical sciences at Cedars-Sinai and a lead author of an article published online in the American Chemical Society's journal ACS Nano.
Ljubimova, director of the Nanomedicine Research center in the Department of Neurosurgery and director of the Nanomedicine Program at the Samuel Oschin Comprehensive Cancer Institute, has received a $2. 5 million grant from the National institutes of health to continue the research.
The drug delivery system and its component parts together called a nanobioconjugate or nanodrug, is in an emerging class of molecular drugs designed to slow
or stop cancers by blocking them in multiple ways within the brain. The drug is about 20 to 30 nanometers in size-a fraction of a human hair,
which is 80,000 to 100,000 nanometers wide. Cedars-Sinai scientists began developing the"platform"of the drug delivery system about a decade ago.
The nanodrug can have a variety of chemical and biological"modules"attached.""Each component serves a specialized function,
such as seeking out cancer cells and binding to them, permeating the walls of blood vessels and tumor cells,
or dismantling molecular mechanisms that promote tumor growth, "said Eggehard Holler, Phd, professor of neurosurgery and director of nanodrug synthesis at Cedars-Sinai.
The new delivery system plays two roles: diagnosing brain tumors by identifying cells that have spread to the brain from other organs,
and then fighting the cancer with precise, individualized tumor treatment. Researchers can determine tumor type by attaching a tracer visible on an MRI.
If the tracer accumulates in the tumor, it will be visible on MRI. With the cancer's molecular makeup identified through this virtual biopsy,
researches can load the"delivery system"with cancer-targeting components that specifically attack the molecular structure.
To show that the virtual biopsies could distinguish one cancer cell type from another, the researchers devised what is believed to be a unique method,
implanting different kinds of breast and lung cancers into laboratory mice to represent metastatic disease-with one type of cancer implanted on each side of the brain.
Lung and breast cancers are those that most often spread to the brain. The researchers used the nano delivery system to identify
and attack the cancers. In each instance, animals that received treatment lived significantly longer than those in control groups."
"Several drugs are quite effective in treating different types of breast cancers, lung cancer, lymphoma and other cancers at their original sites,
but they are ineffective against cancers that spread to the brain because they are not able to cross the blood-brain barrier that protects the brain from toxins in the blood,
"said Keith Black, MD, chair of the Department of Neurosurgery, director of the Maxine Dunitz Neurosurgical Institute, director of the Johnnie L. Cochran, Jr.,
Brain tumor Center and the Ruth and Lawrence Harvey Chair in Neuroscience.""The nanodrug is engineered to cross this barrier with its payload intact,
so drugs that are effective outside the brain may be effective inside as well,"Black added.#####Ljubimova, Black and Holler led the study
and contributed equally to the article. Rameshwar Patil, Phd, a project scientist in Ljubimova's laboratory, is first author.
Researchers from Cedars-Sinai's Department of Neurosurgery, Department of Biomedical sciences, Department of Imaging, and the Samuel Oschin Comprehensive Cancer Institute contributed to the study with colleagues from the University of Southern California and Arrogene Inc,
. a biotech company associated with Cedars-Sinai. The study was supported by NIH grants U01 CA151815, R01 CA136841, R01 CA188743,
and EY013431, Arrogene Inc. grants and Martz Translational Breast cancer Research Fund. The new NIH National Cancer Institute grant
R01ca188743, will fund ongoing study.#####For more information, please click herecontacts: Sandy Vanwriteemail('prpacific. com','sandy';
'808-526-1708copyright Cedars-Sinai Medical Centerissuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Bookmark: Citation:""MRI Virtual Biopsy and Treatment of Brain Metastatic tumors with Targeted Nanobioconjugates.""Publication Date (Web:
April 23, 2015. DOI: 10.1021/acsnano. 5b01872: News and information Who needs water to assemble DNA?
Non-aqueous solvent supports DNA NANOTECHNOLOGY May 27th, 2015controlled Release of Anticorrosive Materials in Spot by Nanocarriers May 27th, 2015production of Copper Cobaltite Nanocomposites with Photocatalytic Properties in Iran
May 27th, 2015fine-tuned molecular orientation is key to more efficient solar cells May 26th, 2015cancer Iranian Scientists Use Magnetic field to Transfer Anticancer Drug to Tumor Tissue May 24th,
2015this Slinky lookalike'hyperlens'helps us see tiny objects: The photonics advancement could improve early cancer detection,
nanoelectronics manufacturing and scientists'ability to observe single molecules May 23rd, 2015nanotherapy effective in mice with multiple myeloma May 21st,
2015imaging This Slinky lookalike'hyperlens'helps us see tiny objects: The photonics advancement could improve early cancer detection,
nanoelectronics manufacturing and scientists'ability to observe single molecules May 23rd, 2015aspen Aerogels to Present at the Cowen and Company Technology,
Media & Telecom Conference May 21st, 2015samtec, Global Provider of Interconnect Systems, Joins IRT Nanoelec Silicon photonics Program May 21st, 2015govt.
-Legislation/Regulation/Funding/Policy Who needs water to assemble DNA? Non-aqueous solvent supports DNA NANOTECHNOLOGY May 27th, 2015one step closer to a single-molecule device:
Columbia Engineering researchers first to create a single-molecule diode--the ultimate in miniaturization for electronic devices--with potential for real-world applications May 25th,
2015dna Double Helix Does Double Duty in Assembling Arrays of Nanoparticles: Synthetic pieces of biological molecule form framework and glue for making nanoparticle clusters and arrays May 25th, 2015engineering Phase changes in Nanoparticle Arrays:
Scientists alter attractive and repulsive forces between DNA-linked particles to make dynamic, phase-shifting forms of nanomaterials May 25th,
2015nanomedicine Who needs water to assemble DNA? Non-aqueous solvent supports DNA NANOTECHNOLOGY May 27th, 2015dna Double Helix Does Double Duty in Assembling Arrays of Nanoparticles:
Synthetic pieces of biological molecule form framework and glue for making nanoparticle clusters and arrays May 25th, 2015nanostructures Increase Corrosion resistance in Metallic Body Implants May 24th, 2015iranian
Scientists Use Magnetic field to Transfer Anticancer Drug to Tumor Tissue May 24th, 2015discoveries Who needs water to assemble DNA?
Non-aqueous solvent supports DNA NANOTECHNOLOGY May 27th, 2015production of Copper Cobaltite Nanocomposites with Photocatalytic Properties in Iran May 27th, 2015fine-tuned molecular orientation is key to more efficient solar cells
May 26th, 2015engineering Phase changes in Nanoparticle Arrays: Scientists alter attractive and repulsive forces between DNA-linked particles to make dynamic, phase-shifting forms of nanomaterials May 25th,
2015announcements Who needs water to assemble DNA? Non-aqueous solvent supports DNA NANOTECHNOLOGY May 27th, 2015controlled Release of Anticorrosive Materials in Spot by Nanocarriers May 27th, 2015production of Copper Cobaltite Nanocomposites with Photocatalytic Properties in Iran
May 27th, 2015fine-tuned molecular orientation is key to more efficient solar cells May 26th, 2015interviews/Book reviews/Essays/Reports/Podcasts/Journals/White papers Who needs water to assemble DNA?
Non-aqueous solvent supports DNA NANOTECHNOLOGY May 27th, 2015controlled Release of Anticorrosive Materials in Spot by Nanocarriers May 27th, 2015production of Copper Cobaltite Nanocomposites with Photocatalytic Properties in Iran
May 27th, 2015fine-tuned molecular orientation is key to more efficient solar cells May 26th, 2015nanobiotechnology Who needs water to assemble DNA?
Non-aqueous solvent supports DNA NANOTECHNOLOGY May 27th, 2015dna Double Helix Does Double Duty in Assembling Arrays of Nanoparticles:
Synthetic pieces of biological molecule form framework and glue for making nanoparticle clusters and arrays May 25th, 2015engineering Phase changes in Nanoparticle Arrays:
Scientists alter attractive and repulsive forces between DNA-linked particles to make dynamic, phase-shifting forms of nanomaterials May 25th,
2015this Slinky lookalike'hyperlens'helps us see tiny objects: The photonics advancement could improve early cancer detection,
nanoelectronics manufacturing and scientists'ability to observe single molecules May 23rd,201 0
#Nanotech Secures Additional Patents in Advanced Security Features: New patented features gain attention from the banknote industry Clint Landrock,
Nanotech Chief Technology officer, commented, e are pleased to be granted these additional patents as they further solidify our hold on the next generation of authentication technologies for the banknote, branding and secure document industries.
EPO No. 2, 563,602 names Charles Macpherson as the inventor. The patent covers layered optically variable devices (VDS such as colour shift foils that uniquely employs additional interactivity using piezoelectric layers to activate the authentication mode of a security device used as threads in products such as banknotes, passports
and secure packaging. This patented multilayered thin film technology offers Nanotech a competitive edge in the development of colour shifting security devices.
USPTO No. 9 013,272 names Dr. Bozena Kaminska and Clint Landrock as co-inventors. Building on patents previously granted to Nanotech,
this patent secures integral intellectual property, which covers a range of diffractive and plasmonic luminescent devices such as security features used in banknotes.
Nanotech has developed some novel high resolution OVD effects based on nanohole arrays, which differ from conventional OVDS providing easy recognition and verification.
These nanohole structures create new colour shifting effects that provide unique visual features such as 3d, HD, and motion.
These unique features are communicated easily to the public making Nanotech overt security features easier to recognize
and authenticate. The Company has created also colour switching effects with predetermined contrast changes. When the device is rotated colours switch,
for example from magenta to gold or blue to green, making for a distinct and recognizable security image.
With its Kolouroptiktm technology Nanotech has created also colours such as white and black, which has not yet been seen in conventional OVDS.
The bright colours and unique visual characteristics not only appeal to human perceptions, but also reinforce a device security properties as they cannot be reproduced by copying or classical holography.
Based on these patents the Company has launched earl our first foray in plasmonic full colour images.
A nano array image of Vermeer famous painting irl with a Pearl Earring which brilliantly displays her ruby lips
blue scarf and bright white collar and features two distinct authentication viewing modes in one feature.
The user can view the full colour image in both transmission and reflection (shining a light on
or through the image) an effect impossible for a hologram to achieve. An example of Pearl can be viewed at:
www. nanosecurity. ca/newsrelease2015may27. Doug Blakeway, Nanotech Chief executive officer, commented, n initial showing of Pearl to the banknote industry came back with comments of having never seen such a bright visual effect in a security device.
Immediate interest in Pearl has initiated discussions with issuing authorities. Nanotech is now focusing its efforts on commercial applications of its technology;
making overt authentication security elements available for integration into banknotes, passports, identity cards, tax stamps, and other security documents t
#Trees are source for high-capacity, soft batteries A method for making elastic high-capacity batteries from wood pulp was unveiled by researchers in Sweden and the US.
Using nanocellulose broken down from tree fibres, a team from KTH Royal Institute of technology and Stanford university produced an elastic,
foam-like battery material that can withstand shock and stress.""It is possible to make incredible materials from trees
and cellulose,"says Max Hamedi, who is a researcher at KTH and Harvard university. One benefit of the new wood-based aerogel material is that it can be used for three-dimensional structures."
"There are limits to how thin a battery can be, but that becomes less relevant in 3d,
"Hamedi says.""We are restricted no longer to two dimensions. We can build in three dimensions, enabling us to fit more electronics in a smaller space."
"A 3d structure enables storage of significantly more power in less space than is possible with conventional batteries,
he says.""Three-dimensional, porous materials have been regarded as an obstacle to building electrodes. But we have proven that this is not a problem.
In fact, this type of structure and material architecture allows flexibility and freedom in the design of batteries,
"Hamedi says. The process for creating the material begins with breaking down tree fibres, making them roughly one million times thinner.
The nanocellulose is dissolved, frozen and then freeze-dried so that the moisture evaporates without passing through a liquid state.
Then the material goes through a process in which the molecules are stabilised so that the material does not collapse."
"The result is a material that is both strong, light and soft, "Hamedi says.""The material resembles foam in a mattress,
though it is a little harder, lighter and more porous. You can touch it without it breaking."
"The finished aerogel can then be treated with electronic properties.""We use a very precise technique,
verging on the atomic level, which adds ink that conducts electricity within the aerogel. You can coat the entire surface within."
"In terms of surface area, Hamedi compares the material to a pair of human lungs, which if unfurled could be spread over a football field.
Similarly, a single cubic decimeter of the battery material would cover most of a football pitch,
he says.""You can press it as much as you want. While flexible and stretchable electronics already exist,
the insensitivity to shock and impact are somewhat new.""Hamedi says the aerogel batteries could be used in electric car bodies,
as well as in clothing, providing the garment has a lining. The research has been carried out at the Wallenberg Wood Science Center at KTH.
KTH Professor Lars Wågberg also has been involved, and his work on aerogels is in the basis for the invention of soft electronics.
Another partner is leading battery researcher, Professor Yi Cui from Stanford university t
#Researchers synthesize magnetic nanoparticles that could offer alternative to Rare earth magnets Abstract: A team of scientists at Virginia Commonwealth University has synthesized a powerful new magnetic material that could reduce the dependence of the United states
and other nations on rare earth elements produced by China.""The discovery opens the pathway to systematically improving the new material to outperform the current permanent magnets,
"said Shiv Khanna, Ph d.,a commonwealth professor in the Department of physics in the College of Humanities and Sciences.
The new material consists of nanoparticles containing iron, cobalt and carbon atoms with a magnetic domain size of roughly 5 nanometers.
It can store information up to 790 kelvins with thermal and time-stable, long-range magnetic order,
which could have a potential impact for data storage application. When collected in powders, the material exhibits magnetic properties that rival those of permanent magnets that generally contain rare earth elements.
The need to generate powerful magnets without rare earth elements is a strategic national problem as nearly 70 to 80 percent of the current rare earth materials are produced in China.
The team's findings will appear in the article"Experimental evidence for the formation of Cofe2c phase with colossal magnetocrystalline-anisotropy,"in a forthcoming issue of Applied Physics Letters.
Permanent magnets, specifically those containing rare earth metals, are an important component used by the electronics, communications and automobile industries,
as well as in radars and other applications. Additionally, the emergence of green technology markets-such as hybrid and electric vehicles, direct drive wind turbine power systems and energy storage systems-have created an increased demand for permanent magnets.
However China is the main supplier of world rare earth demands and has tried to impose restrictions on their export,
creating an international problem. The current paper is a joint experimental theoretical effort in which the new material was synthesized,
characterized and showed improved characteristics following the theoretical prediction.""This is good science along with addressing a problem with national importance,"said Ahmed El-Gendy,
a former postdoctoral associate in the Department of chemistry in the College of Humanities and Sciences and a co-author of the paper.
Everett Carpenter, Ph d.,a professor in the Department of chemistry and director of the VCU's Nanoscience and Nanotechnology Program, said the new material is"already showing promise, even for applications beyond permanent magnets
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