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

Electric-car battery materials could harm key soil bacteria February 11th, 2016

Creating a color printer that uses a colorless, non-toxic ink inspired by nature February 11th, 2016

SLAC X-ray laser turns crystal imperfections into better images of important biomolecules: New method could remove major obstacles to studying structures of complex biological machines February 11th, 2016

Nanoparticle reduces targeted cancer drug's toxicity February 11th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Electric-car battery materials could harm key soil bacteria February 11th, 2016

Creating a color printer that uses a colorless, non-toxic ink inspired by nature February 11th, 2016

SLAC X-ray laser turns crystal imperfections into better images of important biomolecules: New method could remove major obstacles to studying structures of complex biological machines February 11th, 2016

Scientists take nanoparticle snapshots February 10th, 2016

Self Assembly

New type of nanowires, built with natural gas heating: UNIST research team developed a new simple nanowire manufacturing technique February 1st, 2016

Researchers develop completely new kind of polymer: Hybrid polymers could lead to new concepts in self-repairing materials, drug delivery and artificial muscles January 30th, 2016

Polymer nanowires that assemble in perpendicular layers could offer route to tinier chip components January 23rd, 2016

Nanodevice, build thyself: Researchers in Germany studied how a multitude of electronic interactions govern the encounter between a molecule called porphine and copper and silver surfaces January 18th, 2016

Discoveries

Research reveals carbon films can give microchips energy storage capability: International team from Drexel University and Paul Sabatier University reveals versatility of carbon films February 11th, 2016

Canadian Scientists Develop Innovative Protein Test for Zika February 11th, 2016

Creating a color printer that uses a colorless, non-toxic ink inspired by nature February 11th, 2016

SLAC X-ray laser turns crystal imperfections into better images of important biomolecules: New method could remove major obstacles to studying structures of complex biological machines February 11th, 2016

Announcements

Research reveals carbon films can give microchips energy storage capability: International team from Drexel University and Paul Sabatier University reveals versatility of carbon films February 11th, 2016

Creating a color printer that uses a colorless, non-toxic ink inspired by nature February 11th, 2016

SLAC X-ray laser turns crystal imperfections into better images of important biomolecules: New method could remove major obstacles to studying structures of complex biological machines February 11th, 2016

Nanoparticle reduces targeted cancer drug's toxicity February 11th, 2016

Energy

New thin film transistor may lead to flexible devices: Researchers engineer an electronics first, opening door to flexible electronics February 10th, 2016

Canadian physicists discover new properties of superconductivity February 8th, 2016

Host-guest nanowires for efficient water splitting and solar energy storage February 7th, 2016

February 4th, 2016

Solar/Photovoltaic

Host-guest nanowires for efficient water splitting and solar energy storage February 7th, 2016

Simplifying solar cells with a new mix of materials: Berkeley Lab-led research team creates a high-efficiency device in 7 steps January 29th, 2016

An alternative to platinum: Iron-nitrogen compounds as catalysts in graphene January 28th, 2016

Scientists provide new guideline for synthesis of fullerene electron acceptors January 28th, 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