Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Infrared LEDs can be made cheaper, compatible with silicon, say researchers

Abstract:
Light-emitting diodes at infrared wavelengths are the magic behind such things as night vision and optical communications, including the streaming data that comes through Netflix. Cornell researchers have advanced the process of making such LEDs cheaper and easier to fabricate, which could lead to ultra-thin LEDs painted onto silicon to replace computer wiring with light waves.

Infrared LEDs can be made cheaper, compatible with silicon, say researchers

Ithaca, NY | Posted on May 9th, 2012

The research group led by Frank Wise, professor of applied and engineering physics, reported online May 6 in the journal Nature Nanotechnology that they have used solution chemistry to make infrared LEDs out of nanocrystals, commonly known as quantum dots, out of lead sulfide.

Their process, which involves tuning emitted wavelengths based on controlling the size of the nanocrystals, could rival the effective, but expensive, practice of growing semiconductor materials using the atom-by-atom process known as epitaxy. The Cornell nanocrystal LEDs are about as bright as epitaxially grown LEDs, but they were made using low-temperature, solution-based processing that is much cheaper.

Infrared LEDs are usually made of crystals of such materials as indium gallium arsenide, and they cannot be grown on silicon due to their different crystal structures, Wise explained. Thus far there has been no natural way to make light-emitting materials on silicon.

Getting electrons to flow through nanocrystals is a major challenge, Wise said. The Cornell team did it with some clever chemistry: They changed the distance between the nanocrystals by changing the molecules on their surfaces. Longer carbon chains produced bigger spacing, which dramatically affected the efficiency of light emission. Changing the distance between nanocrystals by half a nanometer made the devices 100 times more efficient, Wise said. The researchers found the optimum distances between nanocrystals to make the LEDs emit the brightest light. They measured those distances using X-ray scattering technology provided by the Cornell High Energy Synchrotron Source (CHESS).

Because the Cornell-developed LEDs were made through solution processing, they can be more easily integrated with other materials. They could lead to such breakthroughs as the ability to "paint" the LEDs onto silicon, for example. Such an application would hold sway in optical interconnects, replacing electrical wires that are now a bottleneck for speed of the modern computer chip. Communication between chips with a light wave, rather than a wire, is expected to revolutionize information processing.

The nanocrystals the researchers used have struck interest among people making photovoltaic cells, too. A solar cell absorbs light and emits electrons as electric current, which can supply power. Lead sulfide and lead selenide nanocrystals are leading candidates for replacing cadmium telluride and other materials found in commercial solar cells today.

The paper's co-authors are Tobias Hanrath, assistant professor of chemical and biomolecular engineering, and George Malliaras, formerly an associate professor of materials science and engineering at Cornell; as well as former postdoctoral associate Liangfeng Sun; graduate students Joshua J. Choi, David Stachnik and Adam Bartnik (now a staff member at Wilson Laboratory); and postdoctoral associate Byung-Ryool Hyun.

The work was supported by the National Science Foundation, the KAUST-Cornell Center for Energy and Sustainability, the New York State Foundation for Science, Technology and Innovation and CHESS.

####

For more information, please click here

Contacts:
John Carberry
(607) 255-5353


Anne Ju


Chronicle Online
312 College Ave.
Ithaca, NY 14850
607.255.4206

http://www.news.cornell.edu

Copyright © Cornell University

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

Texas A&M Chemist Says Trapped Electrons To Blame For Lack Of Battery Efficiency: Forget mousetraps — today’s scientists will get the cheese if they manage to build a better battery June 28th, 2016

Building a smart cardiac patch: 'Bionic' cardiac patch could one day monitor and respond to cardiac problems June 28th, 2016

New, better way to build circuits for world's first useful quantum computers June 28th, 2016

Yale researchers’ technology turns wasted heat into power June 27th, 2016

Display technology/LEDs/SS Lighting/OLEDs

GraphExeter illuminates bright new future for flexible lighting devices June 23rd, 2016

New nanomaterial offers promise in bendable, wearable electronic devices: Electroplated polymer makes transparent, highly conductive, ultrathin film June 13th, 2016

Graphene-based transparent electrodes for highly efficient flexible OLEDS: A Korean research team developed an ideal electrode structure composed of graphene and layers of titanium dioxide and conducting polymers, resulting in highly flexible and efficient OLEDs June 5th, 2016

Nanotubes are beacons in cancer-imaging technique: Rice University researchers use spectral triangulation to pinpoint location of tumors May 21st, 2016

Govt.-Legislation/Regulation/Funding/Policy

Nanoscientists develop the 'ultimate discovery tool': Rapid discovery power is similar to what gene chips offer biology June 25th, 2016

Ultrathin, flat lens resolves chirality and color: Multifunctional lens could replace bulky, expensive machines June 25th, 2016

Particle zoo in a quantum computer: First experimental quantum simulation of particle physics phenomena June 23rd, 2016

Titan shines light on high-temperature superconductor pathway: Simulation demonstrates how superconductivity arises in cuprates' pseudogap phase June 22nd, 2016

Discoveries

Texas A&M Chemist Says Trapped Electrons To Blame For Lack Of Battery Efficiency: Forget mousetraps — today’s scientists will get the cheese if they manage to build a better battery June 28th, 2016

Building a smart cardiac patch: 'Bionic' cardiac patch could one day monitor and respond to cardiac problems June 28th, 2016

New, better way to build circuits for world's first useful quantum computers June 28th, 2016

Yale researchers’ technology turns wasted heat into power June 27th, 2016

Announcements

Texas A&M Chemist Says Trapped Electrons To Blame For Lack Of Battery Efficiency: Forget mousetraps — today’s scientists will get the cheese if they manage to build a better battery June 28th, 2016

Building a smart cardiac patch: 'Bionic' cardiac patch could one day monitor and respond to cardiac problems June 28th, 2016

New, better way to build circuits for world's first useful quantum computers June 28th, 2016

Yale researchers’ technology turns wasted heat into power June 27th, 2016

Quantum Dots/Rods

A new form of hybrid photodetectors with quantum dots and graphene June 19th, 2016

Supercrystals with new architecture can enhance drug synthesis May 24th, 2016

ORNL demonstrates large-scale technique to produce quantum dots May 21st, 2016

First single-enzyme method to produce quantum dots revealed: Biological manufacturing process, pioneered by three Lehigh University engineers, produces equivalent quantum dots to those made chemically--but in a much greener, cheaper way May 9th, 2016

Research partnerships

Superheroes are real: Ultrasensitive nonlinear metamaterials for data transfer June 25th, 2016

Soft decoupling of organic molecules on metal June 23rd, 2016

FEI and University of Liverpool Announce QEMSCAN Research Initiative: University of Liverpool will utilize FEI’s QEMSCAN technology to gain a better insight into oil and gas reserves & potentially change the approach to evaluating them June 22nd, 2016

Tailored DNA shifts electrons into the 'fast lane': DNA nanowire improved by altering sequences June 22nd, 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