Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Water Droplets Direct Self-Assembly Process In Thin-Film Materials

Abstract:
You can think of it as origami - very high-tech origami.

Water Droplets Direct Self-Assembly Process In Thin-Film Materials

Champaign, IL | Posted on November 24th, 2009

Researchers at the University of Illinois have developed a technique for fabricating three-dimensional, single-crystalline silicon structures from thin films by coupling photolithography and a self-folding process driven by capillary interactions.

The films, only a few microns thick, offer mechanical bendability that is not possible with thicker pieces of the same material.

"This is a completely different approach to making three-dimensional structures," said Ralph G. Nuzzo, the G. L. Clark Professor of Chemistry at Illinois. "We are opening a new window into what can be done in self-assembly processes."

Nuzzo is corresponding author of a paper accepted for publication in the Proceedings of the National Academy of Sciences. The paper is to be posted on the journal's Early Edition Web site the week of November 23.

As a demonstration of the new capillary-driven, self-assembly process, Nuzzo and colleagues constructed spherical and cylindrical shaped silicon solar cells and evaluated their performance.

The researchers also developed a predictive model that takes into account the type of thin film to be used, the film's mechanical properties and the desired structural shape.

"The model identifies the critical conditions for self-folding of different geometric shapes," said mechanical science and engineering professor K. Jimmy Hsia. "Using the model, we can improve the folding process, select the best material to achieve certain goals, and predict how the structure will behave for a given material, thickness and shape."

To fabricate their free-standing solar cells, the researchers began by using photolithography to define the desired geometric shape on a thin film of single-crystalline silicon, which was mounted on a thicker, insulated silicon wafer. Next, they removed the exposed silicon with etchant, undercut the remaining silicon foil with acid, and released the foil from the wafer. Then they placed a tiny drop of water at the center of the foil pattern.

As the water evaporated, capillary forces pulled the edges of the foil together, causing the foil to wrap around the water droplet.

To retain the desired shape after the water had fully evaporated, the researchers placed a tiny piece of glass, coated with an adhesive, at the center of the foil pattern. The glass "froze" the three-dimensional structure in place, once it had reached the desired folded state.

"The resulting photovoltaic structures, not yet optimized for electrical performance, offer a promising approach for efficiently harvesting solar energy with thin films," said Jennifer A. Lewis, the Thurnauer Professor of Materials Science and Engineering and director of the university's Frederick Seitz Materials Research Laboratory.

Unlike conventional, flat solar cells, the curved, three-dimensional structures also serve as passive tracking optics by absorbing light from nearly all directions.

"We can look forward from this benchmark demonstration to photovoltaic structures made from thin films that behave as though they are optically dense, and much more efficient," Lewis said.

The new self-assembly process can be applied to a variety of thin-film materials, not just silicon, the researchers noted in their paper.

With Nuzzo, Hsia and Lewis, co-authors of the paper are graduate students Xiaoying Guo and Huan Li, and postdoctoral researchers Bok Yeop Ahn and Eric B. Douss.

Hsia is associate dean of the Graduate College and is affiliated with the university's Micro and Nanotechnology Laboratory.

Lewis is affiliated with the department of chemical and biomolecular engineering and the Micro and Nanotechnology Laboratory.

Nuzzo is affiliated with the Institute for Genomic Biology, the Micro and Nanotechnology Laboratory, the materials science and engineering department, and the Frederick Seitz Materials Research Laboratory.

The U.S. Defense Advanced Research Projects Agency, the Department of Energy and the National Science Foundation funded the work.

####

About University of Illinois
Since its founding in 1867, the University of Illinois at Urbana-Champaign has earned a reputation as a world-class leader in research, teaching, and public engagement.

For more information, please click here

Contacts:
James E. Kloeppel
Physical Sciences Editor
217-244-1073

Copyright © University of Illinois

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

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Harnessing solar and wind energy in one device could power the 'Internet of Things' May 26th, 2016

Thermal modification of wood and a complex study of its properties by magnetic resonance May 26th, 2016

Self Assembly

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

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

Discoveries

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Announcements

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Energy

Harnessing solar and wind energy in one device could power the 'Internet of Things' May 26th, 2016

Gigantic ultrafast spin currents: Scientists from TU Wien (Vienna) are proposing a new method for creating extremely strong spin currents. They are essential for spintronics, a technology that could replace today's electronics May 25th, 2016

Light can 'heal' defects in new solar cell materials: Defects in some new electronic materials can be removed by making ions move under illumination May 24th, 2016

Technique improves the efficacy of fuel cells: Research demonstrates a new phase transition from metal to ionic conductor May 18th, 2016

Solar/Photovoltaic

Harnessing solar and wind energy in one device could power the 'Internet of Things' May 26th, 2016

Light can 'heal' defects in new solar cell materials: Defects in some new electronic materials can be removed by making ions move under illumination May 24th, 2016

This 'nanocavity' may improve ultrathin solar panels, video cameras and more May 16th, 2016

New research shows how silver could be the key to gold-standard flexible gadgets: Silver nanowires are an ideal material for current and future flexible touch-screen technologies May 13th, 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