Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Penn Study: Transforming Nanowires Into Nano-Tools Using Cation Exchange Reactions

Abstract:
A team of engineers from the University of Pennsylvania has transformed simple nanowires into reconfigurable materials and circuits, demonstrating a novel, self-assembling method for chemically creating nanoscale structures that are not possible to grow or obtain otherwise.

Penn Study: Transforming Nanowires Into Nano-Tools Using Cation Exchange Reactions

Philadelphia, PA | Posted on October 24th, 2009

The research team, using only chemical reactants, transformed semiconducting nanowires into a variety of useful, nanoscale materials including nanoscale metal strips with periodic stripes and semiconducting patterns, purely metallic nanowires, radial heterostructures and hollow semiconducting nanotubes in addition to other morphologies and compositions.

Researchers used ion exchange, one of the two most common techniques for solid phase transformation of nanostructures. Ion ( cation/anion ) exchange reactions exchange positive or negative ions and have been used to modify the chemical composition of inorganic nanocrystals, as well as create semiconductor superlattice structures. It is the chemical process, for example, that turns hard water soft in many American households.

Future applications of nanomaterials in electronics, catalysis, photonics and bionanotechnology are driving the exploration of synthetic approaches to control and manipulate the chemical composition, structure and morphology of these materials. To realize their full potential, it is desirable to develop techniques that can transform nanowires into tunable but precisely controlled morphologies, especially in the gas-phase, to be compatible with nanowire growth schemes. The assembly, however, is an expensive and labor-intensive process that prohibits cost-effective production of these materials.

Recent research in the field has enabled the transformation of nanomaterials via solid-phase chemical reactions into nonequilibrium, or functional structures that cannot be obtained otherwise.

In this study, researchers transformed single-crystalline cadmium sulfide nanowires into composition-controlled nanowires, core−shell heterostructures, metal-semiconductor superlattices, single-crystalline nanotubes and metallic nanowires by utilizing size-dependent cation-exchange reactions along with temperature and gas-phase reactant delivery control. This versatile, synthetic ability to transform nanowires offers new opportunities to study size-dependent phenomena at the nanoscale and tune their chemical/physical properties to design reconfigurable circuits.

Researchers also found that the speed of the cation exchange process was determined by the size of the starting nanowire and that the process temperature affected the final product, adding new information to the conditions that affect reaction rates and assembly.

"This is almost like magic that a single-component semiconductor nanostructure gets converted into metal-semiconductor binary superlattice, a completely hollow but single crystalline nanotube and even a purely metallic material," said Ritesh Agarwal, assistant professor in the Department of Materials Science and Engineering at Penn. "The important thing here is that these transformations cannot take place in bulk materials where the reaction rates are incredibly slow or in very small nanocrystals where the rates are too fast to be precisely controlled. These unique transformations take place at 5-200 nanometer-length scales where the rates can be controlled very accurately to enable such intriguing products. Now we are working with theoreticians and designing new experiments to unravel this 'magic' at the nanoscale."

The fundamental revelation in this study is a further clarification of nanoscale chemical phenomena. The study also provides new data on how manufacturers can assemble these tiny circuits, electrically connecting nanoscale structures through chemical self-assembly.

It also opens up new possibilities for the transformation of nanoscale materials into the tools and circuits of the future, for example, self-assembling nanoscale electrical contacts to individual nanoscale components, smaller electronic and photonic devices such as a series of electrically connected quantum dots for LEDs or transistors, as well as improved storage capacities for batteries.

The study, published in the current issue of the journal Nano Letters, was conducted by Bin Zhang, Yeonwoong Jung, Lambert Van Vug and Agarwal of the Department of Materials Science and Engineering in Penn's School of Engineering and Applied Science.

The work was supported by a National Science Foundation Career Award and a Penn Materials Research Science and Engineering Center grant.

####

For more information, please click here

Copyright © University of Pennsylvania

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Iranian Scientists Use Artemisia Annua Plant to Produce Breast Cancer Drugs August 29th, 2015

Small but heading for the big time: Nanobiotix half year results for the six months ended 30 June 2015, in line with expectations: Major clinical achievements and corporate developments August 28th, 2015

A new technique to make drugs more soluble August 28th, 2015

Nanocatalysts improve processes for the petrochemical industry August 28th, 2015

Govt.-Legislation/Regulation/Funding/Policy

These microscopic fish are 3-D-printed to do more than swim: Researchers demonstrate a novel method to build microscopic robots with complex shapes and functionalities August 26th, 2015

Glitter from silver lights up Alzheimer's dark secrets August 25th, 2015

Southampton scientists find new way to detect ortho-para conversion in water August 25th, 2015

Industrial Nanotech, Inc. Provides Update On Hospital Project, PCAOB Audit, and New Heat Shield™ Line August 24th, 2015

Chip Technology

Nanometrics to Participate in the Citi 2015 Global Technology Conference August 26th, 2015

Kwansei Gakuin University in Hyogo, Japan, uses Raman microscopy to study crystallographic defects in silicon carbide wafers August 25th, 2015

A little light interaction leaves quantum physicists beaming August 25th, 2015

'Magic' sphere for information transfer: Professor at the Lomonosov Moscow State University made the «magic» sphere for information transfer August 24th, 2015

Self Assembly

Louisiana Tech University researchers discover synthesis of a new nanomaterial: Interdisciplinary team creates biocomposite for first time using physiological conditions August 24th, 2015

Novel nanostructures for efficient long-range energy transport August 21st, 2015

Biophysics: Formation of swarms in nanosystems August 18th, 2015

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Nanoelectronics

Nanotechnology that will impact the Security & Defense sectors to be discussed at NanoSD2015 conference August 25th, 2015

'Quantum dot' technology may help light the future August 19th, 2015

Surprising discoveries about 2-D molybdenum disulfide: Berkeley Lab researchers use award-winning campanile probe on promising semiconductor August 15th, 2015

Better together: Graphene-nanotube hybrid switches August 3rd, 2015

Discoveries

Iranian Scientists Use Artemisia Annua Plant to Produce Breast Cancer Drugs August 29th, 2015

A new technique to make drugs more soluble August 28th, 2015

Nanocatalysts improve processes for the petrochemical industry August 28th, 2015

CWRU researchers efficiently charge a lithium-ion battery with solar cell: Coupling with perovskite solar cell holds potential for cleaner cars and more August 27th, 2015

Announcements

Iranian Scientists Use Artemisia Annua Plant to Produce Breast Cancer Drugs August 29th, 2015

Small but heading for the big time: Nanobiotix half year results for the six months ended 30 June 2015, in line with expectations: Major clinical achievements and corporate developments August 28th, 2015

A new technique to make drugs more soluble August 28th, 2015

Nanocatalysts improve processes for the petrochemical industry August 28th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic