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

Non-animal approach to predict impact of nanomaterials on human lung published Archives of Toxicology publishes workshop recommendations May 2nd, 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

New drug-delivery approach holds potential for treating obesity May 2nd, 2016

Spintronics for future information technologies: Spin currents in topological insulators controlled May 2nd, 2016

Display technology/LEDs/SS Lighting/OLEDs

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

Manipulating light inside opaque layers April 24th, 2016

Highlights from the Graphene Flagship April 22nd, 2016

What screens are made of: New twists (and bends) in LCD research: X-ray research at Berkeley Lab details exotic structure formed by liquid crystals April 19th, 2016

Govt.-Legislation/Regulation/Funding/Policy

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

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

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

Personal cooling units on the horizon April 29th, 2016

Chip Technology

Spintronics for future information technologies: Spin currents in topological insulators controlled May 2nd, 2016

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

Exploring phosphorene, a promising new material April 29th, 2016

Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers April 28th, 2016

Announcements

Non-animal approach to predict impact of nanomaterials on human lung published Archives of Toxicology publishes workshop recommendations May 2nd, 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

New drug-delivery approach holds potential for treating obesity May 2nd, 2016

Spintronics for future information technologies: Spin currents in topological insulators controlled May 2nd, 2016

Energy

Nanoparticles present sustainable way to grow food crops May 1st, 2016

NREL finds nanotube semiconductors well-suited for PV systems April 27th, 2016

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

Flipping a chemical switch helps perovskite solar cells beat the heat April 26th, 2016

Solar/Photovoltaic

NREL finds nanotube semiconductors well-suited for PV systems April 27th, 2016

Flipping a chemical switch helps perovskite solar cells beat the heat April 26th, 2016

Manipulating light inside opaque layers April 24th, 2016

Thin-film solar cells: How defects appear and disappear in CIGSe cells: Concentration of copper plays a crucial role April 23rd, 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