Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pumping energy to nanocrystals from a quantum well

14.06.2004


University of California scientists working at Los Alamos National Laboratory with a colleague from Sandia National Laboratories have developed a new method for exciting light emission from nanocrystal quantum dots. The discovery provides a way to supply energy to quantum dots without wires, and paves the way for a potentially wider use of tunable nanocrystalline materials in a variety of novel light-emitting technologies ranging from electronic displays to solid-state lighting and electrically pumped nanoscale lasers.



In a paper published in the today’s issue of the scientific journal Nature, Los Alamos Chemistry Division scientist Victor Klimov and his colleagues describe their method for using non-contact, non-radiative energy transfer from a quantum well to produce light from an adjacent layer of nanocrystals. A quantum well is a semiconductor structure in which an electron is sandwiched between two barriers so that its motion is confined to two dimensions. In a real-life device, the quantum well would be pumped electrically in the same way a common quantum-well light-emitting diode is pumped.

According to Klimov, "The transfer of energy is fast enough to compete with exciton recombination in the quantum well, and that allows us to "move" more than 50 percent of the excitons to adjacent quantum dots. The recombination of these transferred excitons leads to emission of light with color that can be controlled by quantum dot size. The high efficiency of energy transfer in combination with the exceptional luminescent properties of nanocrystal quantum dots make hybrid quantum-well/nanocrystal devices feasible as efficient sources of any color light -- or even white light."


In addition to Klimov, project scientists include Marc Achermann, Melissa Petruska, Simon Kos and Darryl Smith from Los Alamos, along with Daniel Koleske from Sandia National Laboratories.

Quantum dot research at Los Alamos has led to a number of innovations over the past several years, including news ways to observe and manipulate nanodots and methods for making semiconductor nanocrystals respond to photons by producing multiple electrons as a result of impact ionization (http://www.lanl.gov/orgs/pa/newsbulletin/2004/05/03/text02.shtml). That innovation has potential applications in a new generation of solar cells that would produce as much as 35 percent more electrical output than current solar cells.

The nanocrystal quantum dot research is funded by DOE’s Office of Basics Energy Sciences and by the Los Alamos Laboratory-Directed Research and Development (LDRD) program. LDRD funds basic and applied research and development focusing on employee-initiated creative proposals selected at the discretion of the Laboratory director.

Additional information on Los Alamos quantum dot research is available at http://quantumdot.lanl.gov/ online.

Los Alamos National Laboratory is operated by the University of California for the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy and works in partnership with NNSA’s Sandia and Lawrence Livermore national laboratories to support NNSA in its mission.

Los Alamos enhances global security by ensuring the safety and reliability of the U.S. nuclear deterrent, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to defense, energy, environment, infrastructure, health and national security concerns.

Note to news media/editors: an image is available at http://www.lanl.gov/worldview/news/photos/achermann7RED.jpg online.

Photo credit: Los Alamos National Laboratory

Todd Hanson | LANL
Further information:
http://www.lanl.gov/worldview/news/releases/archive/04-053.shtml

More articles from Power and Electrical Engineering:

nachricht Researchers take next step toward fusion energy
16.11.2017 | Texas A&M University

nachricht Desert solar to fuel centuries of air travel
16.11.2017 | SolarPACES

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Researchers at IST Austria define function of an enigmatic synaptic protein

22.11.2017 | Life Sciences

Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes

22.11.2017 | Materials Sciences

Women and lung cancer – the role of sex hormones

22.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>