Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > UCSB Researchers Uncover Transparency Limits on Transparent Conducting Oxides: Computational Materials researchers at UC Santa Barbara use cutting-edge calculations to determine fundamental optical transparency limits in conducting oxide material tin oxide

Three beams of light (red for infrared, yellow for visible light, and violet for ultraviolet) travel through a layer of SnO2. Absorption by the conduction electrons in the oxide reduces the intensity of the beams. Credit: Hartwin Peelaers, UCSB
Three beams of light (red for infrared, yellow for visible light, and violet for ultraviolet) travel through a layer of SnO2. Absorption by the conduction electrons in the oxide reduces the intensity of the beams.

Credit: Hartwin Peelaers, UCSB

Abstract:
Researchers in the Computational Materials Group at the University of California, Santa Barbara (UCSB) have uncovered the fundamental limits on optical transparency in the class of materials known as transparent conducting oxides. Their discovery will support development of energy efficiency improvements for devices that depend on optoelectronic technology, such as light- emitting diodes and solar cells.

UCSB Researchers Uncover Transparency Limits on Transparent Conducting Oxides: Computational Materials researchers at UC Santa Barbara use cutting-edge calculations to determine fundamental optical transparency limits in conducting oxide material tin oxide

Santa Barbara, CA | Posted on January 18th, 2012

Transparent conducting oxides are used as transparent contacts in a wide range of optoelectronic devices, such as photovoltaic cells, light-emitting diodes (LEDs), and LCD touch screens. These materials are unique in that they can conduct electricity while being transparent to visible light. For optoelectronic devices to be able to emit or absorb light, it is important that the electrical contacts at the top of the device are optically transparent. Opaque metals and most transparent materials lack the balance between these two characteristics to be functional for use in such technology.

In a paper published in Applied Physics Letters [APL 100, 011914 (2012)], the UCSB researchers used cutting-edge calculation methods to investigate tin dioxide (SnO2), a widely-used conducting oxide.

Conducting oxides strike an ideal balance between transparency and conductivity because their wide band gaps prevent absorption of visible light by excitation of electrons across the gap, according to the researchers. At the same time, dopant atoms provide additional electrons in the conduction band that enable electrical conductivity. However, these free electrons can also absorb light by being excited to higher conduction-band states.

"Direct absorption of visible light cannot occur in these materials because the next available electron level is too high in energy. But we found that more complex absorption mechanisms, which also involve lattice vibrations, can be remarkably strong", says Hartwin Peelaers, a postdoctoral researcher and the lead author of the paper. The other authors are Emmanouil Kioupakis, now at the University of Michigan, and Chris Van de Walle, a professor in the UCSB Materials Department and head of the research group.

They found that tin dioxide only weakly absorbs visible light, thus letting most light pass through, so that it is still a useful transparent contact. In their study, the transparency of SnO2 declined when moving to other wavelength regions. Absorption was 5 times stronger for ultraviolet light and 20 times stronger for the infrared light used in telecommunications.

"Every bit of light that gets absorbed reduces the efficiency of a solar cell or LED", remarked Chris Van de Walle. "Understanding what causes the absorption is essential for engineering improved materials to be used in more efficient devices."

Van de Walle's Computational Materials Group is affiliated with the College of Engineering at UCSB. Their research explores semiconducting binary oxides, nitride semiconductors, novel channel materials and dielectrics, materials for quantum computing, photochemical hydrogen generation, and metallic nanoparticles. Learn more about Computational Materials research at www.mrl.ucsb.edu/~vandewalle .

Their research was supported as part of the UCSB Center for Energy Efficient Materials, an Energy Frontier Research Center funded by the United States Department of Energy, by the Belgian American Educational Foundation, and by the UCSB Materials Research Laboratory: a National Science Foundation MRSEC.

####

For more information, please click here

Contacts:
Melissa Van De Werfhorst
Communications Manager
UCSB College of Engineering
(805) 893-4301

Copyright © University of California, Santa Barbara (UCSB)

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 Links

Faculty Profile - Chris Van de Walle:

UCSB Computation Materials Group:

Applied Physics Letters Paper:

Download this release as a .pdf:

Related News Press

News and information

National Science Foundation Selects SUNY Poly CNSE for Expanded $2.1M Northeast Advanced Technological Education Center: NSF Center Locates to NanoCollege in Support of Flourishing Tech Industry in NYS September 1st, 2015

RUSNANOPRIZE Directorate Announces New Deadline for Nominations Submission – September 11, 2015 September 1st, 2015

$200K Awarded to Develop In Vitro Lung Test for Toxicity of Inhaled Nanomaterials: In Vitro Lung Test Designed to Protect Human Health and Replace Animal Testing September 1st, 2015

Hot electrons point the way to perfect light absorption: Physicists study how to achieve perfect absorption of light with the help of rough ultrathin films September 1st, 2015

Display technology/LEDs/SS Lighting/OLEDs

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

High-precision control of nanoparticles for digital applications August 19th, 2015

Flexible, biodegradable device can generate power from touch (video) August 12th, 2015

New research may enhance display & LED lighting technology: Large-area integration of quantum dots and photonic crystals produce brighter and more efficient light August 9th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Sustainable nanotechnology center September 1st, 2015

National Science Foundation Selects SUNY Poly CNSE for Expanded $2.1M Northeast Advanced Technological Education Center: NSF Center Locates to NanoCollege in Support of Flourishing Tech Industry in NYS September 1st, 2015

An engineered surface unsticks sticky water droplets August 31st, 2015

New material science research may advance tech tools August 31st, 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

Announcements

$200K Awarded to Develop In Vitro Lung Test for Toxicity of Inhaled Nanomaterials: In Vitro Lung Test Designed to Protect Human Health and Replace Animal Testing September 1st, 2015

Hot electrons point the way to perfect light absorption: Physicists study how to achieve perfect absorption of light with the help of rough ultrathin films September 1st, 2015

Using DNA origami to build nanodevices of the future September 1st, 2015

Nanotech could rid cattle of ticks, with less collateral damage September 1st, 2015

Energy

RUSNANOPRIZE Directorate Announces New Deadline for Nominations Submission – September 11, 2015 September 1st, 2015

Hot electrons point the way to perfect light absorption: Physicists study how to achieve perfect absorption of light with the help of rough ultrathin films September 1st, 2015

Artificial leaf harnesses sunlight for efficient fuel production August 30th, 2015

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

Solar/Photovoltaic

Hot electrons point the way to perfect light absorption: Physicists study how to achieve perfect absorption of light with the help of rough ultrathin films September 1st, 2015

Artificial leaf harnesses sunlight for efficient fuel production August 30th, 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

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