Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Collaboration Leads to Simpler Method for Building Varieties of Nanocrystal Superlattices

Electron microscopes show the preparation of BNSL membranes on the left, with higher magnification shown on the right. (Credit: University of Pennsylvania)
Electron microscopes show the preparation of BNSL membranes on the left, with higher magnification shown on the right. (Credit: University of Pennsylvania)

Abstract:
Collaboration by chemists, physicists and materials scientists at the University of Pennsylvania has created a simple and inexpensive method to rapidly grow centimeter-scale membranes of binary nanocrystal superlattices, or BNSLs, by crystallizing a mixture of nanocrystals on a liquid surface.

Collaboration Leads to Simpler Method for Building Varieties of Nanocrystal Superlattices

Philadelphia, PA | Posted on July 22nd, 2010

The study demonstrates a new and spontaneous way to grow long-range-ordered BNSL membranes with rigorous control of nanocrystal size, shape and concentration by combining two types of nanocrystals and assembling them during a drying stage at the surface of a liquid under normal conditions.

The method overcomes several limitations of the existing assembly strategies and produces large, free-standing membranes that can be transferred to any desired substrate such as silicon wafers, glass slides and plastic substrates, allowing the nanocryatalline films to be introduced at any stage in the device fabrication process.

The team demonstrated the potential for integrating these novel materials by growing millimeter-scale superlattice membranes containing iron oxide nanocrystals of two different sizes and incorporating the membranes into magnetoresistive devices. Measurements showed that the magnetoresistance of the resulting device was dependent on the structure of the BNSL and therefore controllable.

The physical properties intrinsic in these nanocrystals -- nanometer sized crystalline building blocks offer a modern twist on the studies of interfacial assembly that reach as far back as Penn founder Benjamin Franklin and his studies of oil spreading on water in the 1770s.

Single and multi-component nanocrystal films are already under intense investigation by researchers as enablers of novel optical technologies that range from low-cost solar cells, light-emitting diodes and photo detectors and also in electronic systems that include field-effect transistors and solid-state thermoelectric coolers and generators and magnetic technologies that include magnetic recording materials and magnetic sensors and even as tailored electrocatalytic and photocatalytic films.

Co-assembly of two types of nanocrytals into BNSLs provides a low-cost, modular route to program the self assembly of materials with a precisely controlled combinations of properties. Advances in these complex interfacial assemblies and improvements in the transfer of single-component nanocrystal membranes in the past few years have heightened anticipation that this control could be extended to much more complex systems.

This Penn study establishes a route to free-standing large-area BNSLs membranes with the added ability to laminate them on any arbitrary substrate.

"Fundamentally, growing BNSLs on a liquid surface will shed light on the mechanisms of multi-component nanocrystal assembly, which are critical to new concepts in self-assembly based nanomanufacturing," said Christopher B. Murray, the Richard Perry University Professor of Chemistry and Material Science and Engineering at Penn.

The research, funded by the U.S. Army Research Office and a National Science Foundation Materials Research Science and Engineering Centers Award, is published in this week's Nature.

Existing strategies for growing BNSLs involve a more complex process of evaporating a two-nanocrystal solution on a solid substrate under carefully regulated temperature and pressure that influence BNSL formation. The method suffers from several limitations, most notably a limited choice of substrate, nucleation of irregular micrometer-sized, isolated islands of BNSLs on the substrates and an inability to transfer them once formed.

"Given the fact that this novel assembly strategy is general for different nanocrystal combinations, we anticipate that membranes of quasicrystalline BNSLs and ternary nanocrystal superlattices will also be grown by this method, greatly expanding the systems that can be explored" Murray said. "Our dream is to program the organization of materials on all lengths scales for nanometers to millimeters combining the desirable physical properties multiple nanoscale systems. Fundamentally we are focused on identifying, understanding and optimizing new synergistic interactions in nanomaterials and in exploiting these emergent properties in new devices and systems."

This interdisciplinary study was conducted by Murray and Angang Dong in the Department of Chemistry in the School of Arts and Sciences and the Department of Materials Science and Engineering in the School of Engineering and Applied Science, Jun Chen of Materials Science and Engineering and Patrick M. Vora and James M. Kikkawa of the Department of Physics and Astronomy in SAS.

Additional information on research funded by the National Science Foundation Materials Research Science and Engineering Centers is available at www.mrsec.org

####

For more information, please click here

Contacts:
Media Contact:
Jordan Reese

215-573-6604

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

Molybdenum disulfide holds promise for light absorption: Rice researchers probe light-capturing properties of atomically thin MoS2 May 5th, 2016

Oxford Instruments Asylum Research and McGill University Announce the McGill AFM Summer School and Workshop, May 12-13, 2016 May 4th, 2016

The intermediates in a chemical reaction photographed 'red-handed' Researchers at the UPV/EHU-University of the Basque Country have for the first time succeeded in imaging all the steps in a complex organic reaction and have resolved the mechanisms that explain it May 4th, 2016

New tool allows scientists to visualize 'nanoscale' processes May 4th, 2016

Academic/Education

Oxford Instruments Asylum Research and McGill University Announce the McGill AFM Summer School and Workshop, May 12-13, 2016 May 4th, 2016

JPK reports on the use of a NanoWizard AFM system at the University of Kaiserslautern to study the interaction of bacteria with microstructured surfaces April 28th, 2016

The Ottawa Hospital Research Institute uses the ZetaView from Particle Metrix to study membrane microparticles as potential biomarkers for underlying diseases April 12th, 2016

FEI Partners with Five Pharmaceutical Companies, the Medical Research Council and the University of Cambridge to form Cryo-EM Research Consortium April 5th, 2016

Self Assembly

Searching for a nanotech self-organizing principle May 1st, 2016

Researchers create artificial protein to control assembly of buckyballs April 27th, 2016

Brookhaven's Oleg Gang Named a Battelle 'Inventor of the Year': Recognized for work using DNA to guide and regulate the self-assembly of nanoparticles into clusters and arrays with controllable properties April 25th, 2016

Researchers develop new semiconducting polymer for forthcoming flexible electronics April 21st, 2016

Announcements

Molybdenum disulfide holds promise for light absorption: Rice researchers probe light-capturing properties of atomically thin MoS2 May 5th, 2016

Oxford Instruments Asylum Research and McGill University Announce the McGill AFM Summer School and Workshop, May 12-13, 2016 May 4th, 2016

The intermediates in a chemical reaction photographed 'red-handed' Researchers at the UPV/EHU-University of the Basque Country have for the first time succeeded in imaging all the steps in a complex organic reaction and have resolved the mechanisms that explain it May 4th, 2016

New tool allows scientists to visualize 'nanoscale' processes May 4th, 2016

Research partnerships

The intermediates in a chemical reaction photographed 'red-handed' Researchers at the UPV/EHU-University of the Basque Country have for the first time succeeded in imaging all the steps in a complex organic reaction and have resolved the mechanisms that explain it May 4th, 2016

Making invisible physics visible: The Jayich Lab has created a new sensor technology that captures nanoscale images with high spatial resolution and sensitivity May 2nd, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

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