Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Forcing mismatched elements together could yield better solar cells

Abstract:
In what could be a step toward higher efficiency solar cells, an international team including University of Michigan professors has invalidated the most commonly used model to explain the behavior of a unique class of materials called highly mismatched alloys.

Forcing mismatched elements together could yield better solar cells

Ann Arbor, MI | Posted on September 10th, 2010

U-M professors from the departments of Materials Science and Engineering, and Physics contributed to this research.

Highly mismatched alloys, which are still in the experimental stages of development, are combinations of elements that won't naturally mix together using conventional crystal growth techniques. Professor Rachel Goldman compares them to some extent to homogenized milk, in which the high-fat cream and low-fat milk that would naturally separate are forced to mix together at high pressure.

New mixing methods such as "molecular beam epitaxy" are allowing researchers to combine disparate elements. The results, Goldman says, are more dramatic than smooth milk.

"Highly mismatched alloys have very unusual properties," said Goldman, a professor in the departments of Materials Science and Engineering, and Physics. "You can add just a sprinkle of one element and drastically change the electrical and optical properties of the alloy."

Solar cells convert energy from the sun into electricity by absorbing light. However, different materials absorb light at different wavelengths. The most efficient solar cells are made of multiple materials that together can capture a greater portion of the electromagnetic radiation in sunlight. The best solar cells today are still missing a material that can make use of a portion of the sun's infrared light.

Goldman's team made samples of gallium arsenide nitride, a highly mismatched alloy that is spiked with nitrogen, which can tap into that underutilized infrared radiation.

The researchers used molecular beam epitaxy to coax the nitrogen to mix with their other elements. Molecular beam epitaxy involves vaporizing pure samples of the mismatched elements and combining them in a vacuum.

Next, the researchers measured the alloy's ability to convert heat into electricity. They wanted to determine whether its 10 parts per million of nitrogen were distributed as individual atoms or as clusters. They found that in some cases, the nitrogen atoms had grouped together, contrary to what the prevailing "band anti-crossing" model predicted.

"We've shown experimentally that the band anti-crossing model is too simple to explain the electronic properties of highly mismatched alloys," Goldman said. "It does not quantitatively explain several of their extraordinary optical and electronic properties. Atomic clusters have a significant impact on the electronic properties of alloy films."

If researchers can learn to control the formation of these clusters, they could build materials that are more efficient at converting light and heat into electricity, Goldman said.

"The availability of higher efficiency thermoelectrics would make it more practical to generate electricity from waste heat such as that produced in power plants and car engines," Goldman said.

This research will be published in the Sept. 15 issue of Physical Review B. The paper is entitled "Nitrogen composition dependence of electron effective mass in gallium arsenide nitride." Authors include Goldman, as well as Cagliyan Kurdak, an associate professor in the Department of Physics, and Ctirad Uher, a professor in the Department of Physics.

This research was conducted in laboratories of the Center for Solar and Thermal Energy Conversion (CSTEC), a Department of Energy Energy Frontiers Research Center at the University of Michigan. The research was funded by the National Science Foundation, the Science Foundation Ireland, and CSTEC.

####

For more information, please click here

Contacts:
Nicole Casal Moore
(734) 647-7087

Copyright © University of Michigan

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

Future flexible electronics based on carbon nanotubes: Study in Applied Physics Letters show how to improve nanotube transistor and circuit performance with fluoropolymers September 23rd, 2014

Nanotubes help healing hearts keep the beat: Rice University, Texas Children’s Hospital patch for defects enhances electrical connections between cells September 23rd, 2014

Immune system is key ally in cyberwar against cancer: Rice University study yields new two-step strategy for weakening cancer September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Govt.-Legislation/Regulation/Funding/Policy

Southampton scientists grow a new challenger to graphene September 23rd, 2014

Nanotubes help healing hearts keep the beat: Rice University, Texas Children’s Hospital patch for defects enhances electrical connections between cells September 23rd, 2014

Immune system is key ally in cyberwar against cancer: Rice University study yields new two-step strategy for weakening cancer September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Possible Futures

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Local girl does good March 22nd, 2014

Materials/Metamaterials

Southampton scientists grow a new challenger to graphene September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Engineered proteins stick like glue — even in water: New adhesives based on mussel proteins could be useful for naval or medical applications September 22nd, 2014

New star-shaped molecule breakthrough: Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created September 22nd, 2014

Announcements

Future flexible electronics based on carbon nanotubes: Study in Applied Physics Letters show how to improve nanotube transistor and circuit performance with fluoropolymers September 23rd, 2014

Nanotubes help healing hearts keep the beat: Rice University, Texas Children’s Hospital patch for defects enhances electrical connections between cells September 23rd, 2014

Immune system is key ally in cyberwar against cancer: Rice University study yields new two-step strategy for weakening cancer September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Environment

Iranian Nano Scientists Create Flame-Resistant Polymers September 13th, 2014

NanoStruck has a High Recovery Rate on Mine Tailings: retrieval of up to 96% of Gold, 88% of Silver and 86% of Palladium September 12th, 2014

Nanostruck announces 87.6% recovery of 56 GMS/ton silver tailings samples September 12th, 2014

Boosting armor for nuclear-waste eating microbes September 12th, 2014

Energy

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Production of Organometallic Frameworks in Least Possible Time September 23rd, 2014

Iranian Researchers Synthesize Stable Ceramic Nanopowders at Room Temperature September 20th, 2014

IEEE International Electron Devices Meeting To Celebrate 60th Anniversary as The Leading Technical Conference for Advanced Semiconductor Devices September 18th, 2014

Research partnerships

Future flexible electronics based on carbon nanotubes: Study in Applied Physics Letters show how to improve nanotube transistor and circuit performance with fluoropolymers September 23rd, 2014

Biosensors Get a Boost from Graphene Partnership: $5 Million Investment Supports Dozens of Jobs and Development of 300mm Fabrication Process and Wafer Transfer Facility September 18th, 2014

The Pocket Project will develop a low-cost and accurate point-of-care test to diagnose Tuberculosis: ICN2 holds a follow-up meeting of the Project on September 18th - 19th September 18th, 2014

Recruiting bacteria to be technology innovation partners: September 17th, 2014

Solar/Photovoltaic

Simple, Cost-Effective Method Proposed for Synthesizing Zinc Oxide Nanopigments September 15th, 2014

Indium/Copper Sulfide Compound Semi-Conductor Synthesized through New Method September 8th, 2014

Material development on the nanoscale: Doped graphene nanoribbons with potential September 8th, 2014

Layered graphene sandwich for next generation electronics September 8th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE