Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Shiny quantum dots brighten future of solar cells: Photovoltaic solar-panel windows could be next for your house

This schematic shows how the quantum dots are embedded in the plastic matrix and capture sunlight to improve solar panel efficiency.
This schematic shows how the quantum dots are embedded in the plastic matrix and capture sunlight to improve solar panel efficiency.

Abstract:
A house window that doubles as a solar panel could be on the horizon, thanks to recent quantum-dot work by Los Alamos National Laboratory researchers in collaboration with scientists from University of Milano-Bicocca (UNIMIB), Italy. Their project demonstrates that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight.

Shiny quantum dots brighten future of solar cells: Photovoltaic solar-panel windows could be next for your house

Los Alamos, NM | Posted on April 14th, 2014

"The key accomplishment is the demonstration of large-area luminescent solar concentrators that use a new generation of specially engineered quantum dots," said lead researcher Victor Klimov of the Center for Advanced Solar Photophysics (CASP) at Los Alamos.

Quantum dots are ultra-small bits of semiconductor matter that can be synthesized with nearly atomic precision via modern methods of colloidal chemistry. Their emission color can be tuned by simply varying their dimensions. Color tunability is combined with high emission efficiencies approaching 100 percent. These properties have recently become the basis of a new technology - quantum dot displays - employed, for example, in the newest generation of the Kindle Fire ™ e-reader.

Light-harvesting antennas

A luminescent solar concentrator (LSC) is a photon management device, representing a slab of transparent material that contains highly efficient emitters such as dye molecules or quantum dots. Sunlight absorbed in the slab is re-radiated at longer wavelengths and guided towards the slab edge equipped with a solar cell.

Klimov explained, "The LSC serves as a light-harvesting antenna which concentrates solar radiation collected from a large area onto a much smaller solar cell, and this increases its power output."

"LSCs are especially attractive because in addition to gains in efficiency, they can enable new interesting concepts such as photovoltaic windows that can transform house facades into large-area energy generation units," said Sergio Brovelli, who worked at Los Alamos until 2012 and is now a faculty member at UNIMIB.

Because of highly efficient, color-tunable emission and solution processability, quantum dots are attractive materials for use in inexpensive, large-area LSCs. One challenge, however, is an overlap between emission and absorption bands in the dots, which leads to significant light losses due to the dots re-absorbing some of the light they produce.

"Giant" but still tiny, engineered dots

To overcome this problem the Los Alamos and UNIMIB researchers have developed LSCs based on quantum dots with artificially induced large separation between emission and absorption bands (called a large Stokes shift).

These "Stokes-shift" engineered quantum dots represent cadmium selenide/cadmium sulfide (CdSe/CdS) structures in which light absorption is dominated by an ultra-thick outer shell of CdS, while emission occurs from the inner core of a narrower-gap CdSe. The separation of light-absorption and light-emission functions between the two different parts of the nanostructure results in a large spectral shift of emission with respect to absorption, which greatly reduces losses to re-absorption.

To implement this concept, Los Alamos researchers created a series of thick-shell (so-called "giant") CdSe/CdS quantum dots, which were incorporated by their Italian partners into large slabs (sized in tens of centimeters) of polymethylmethacrylate (PMMA). While being large by quantum dot standards, the active particles are still tiny - only about hundred angstroms across. For comparison, a human hair is about 500,000 angstroms wide.

"A key to the success of this project was the use of a modified industrial method of cell-casting, we developed at UNIMIB Materials Science Department" said Francesco Meinardi, professor of Physics at UNIMIB.

Spectroscopic measurements indicated virtually no losses to re-absorption on distances of tens of centimeters. Further, tests using simulated solar radiation demonstrated high photon harvesting efficiencies of approximately 10% per absorbed photon achievable in nearly transparent samples, perfectly suited for utilization as photovoltaic windows.

Despite their high transparency, the fabricated structures showed significant enhancement of solar flux with the concentration factor of more than four. These exciting results indicate that "Stokes-shift-engineered" quantum dots represent a promising materials platform. It may enable the creation of solution processable large-area LSCs with independently tunable emission and absorption spectra.

Publication: A research paper, "Large-area luminescent solar concentrators based on ‘Stokes-shift-engineered' nanocrystals in a mass-polymerized PMMA matrix," is published online this week in Nature Photonics.

Funding: The Center for Advanced Solar Photophyscis (CASP) is an Energy Frontier Research Center funded by the Office of Science of the US Department of Energy.

The work of the UNIMIB team was conducted within the UNIMIB Department of Materials Science and funded by Fondazione Cariplo (2012-0844) and the European Community's Seventh Framework Programme (FP7/2007-2013; grant agreement no. 324603).

####

About Los Alamos National Laboratory
Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and URS Corporation for the Department of Energy’s National Nuclear Security Administration.

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

For more information, please click here

Contacts:
Nancy Ambrosiano
(505) 667-0471

Copyright © Los Alamos National Laboratory

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

Download paper:

Related News Press

News and information

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

NanoScience: Giants of the Infinitesimal July 31st, 2014

New imaging agent provides better picture of the gut July 30th, 2014

Nanometrics Reports Second Quarter 2014 Financial Results July 30th, 2014

Laboratories

Stanford team achieves 'holy grail' of battery design: A stable lithium anode - Engineers use carbon nanospheres to protect lithium from the reactive and expansive problems that have restricted its use as an anode July 27th, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

Sono-Tek Corporation Announces New Clean Room Rated Laboratory Facility in China July 18th, 2014

Fundamental Chemistry Findings Could Help Extend Moore’s Law: A Berkeley Lab-Intel collaboration outlines the chemistry of photoresist, enabling smaller features for future generations of microprocessors July 15th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

New imaging agent provides better picture of the gut July 30th, 2014

Watching Schrödinger's cat die (or come to life): Steering quantum evolution & using probes to conduct continuous error correction in quantum computers July 30th, 2014

Nature inspires a greener way to make colorful plastics July 30th, 2014

Discoveries

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

New imaging agent provides better picture of the gut July 30th, 2014

Watching Schrödinger's cat die (or come to life): Steering quantum evolution & using probes to conduct continuous error correction in quantum computers July 30th, 2014

From Narrow to Broad July 30th, 2014

Announcements

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

NanoScience: Giants of the Infinitesimal July 31st, 2014

Analytical solutions from Malvern Instruments support University of Wisconsin-Milwaukee researchers in understanding environmental effects of nanomaterials July 30th, 2014

FEI Unveils New Solutions for Faster Time-to-Analysis in Metals Research July 30th, 2014

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

NanoScience: Giants of the Infinitesimal July 31st, 2014

Watching Schrödinger's cat die (or come to life): Steering quantum evolution & using probes to conduct continuous error correction in quantum computers July 30th, 2014

From Narrow to Broad July 30th, 2014

Energy

From Narrow to Broad July 30th, 2014

Oregon chemists eye improved thin films with metal substitution: Solution-based inorganic process could drive more efficient electronics and solar devices July 21st, 2014

Steam from the sun: New spongelike structure converts solar energy into steam July 21st, 2014

3-D nanostructure could benefit nanoelectronics, gas storage: Rice U. researchers predict functional advantages of 3-D boron nitride July 15th, 2014

Industrial

University of Manchester selects Anasys AFM-IR for coatings and corrosion research July 30th, 2014

FEI Unveils New Solutions for Faster Time-to-Analysis in Metals Research July 30th, 2014

Iranian Scientists Produce Transparent Nanocomposite Coatings with Longer Lifetime July 24th, 2014

Compact Vibration Harvester Power Supply with Highest Efficiency Opens Door to “Fix-and-Forget” Sensor Nodes July 23rd, 2014

Quantum Dots/Rods

Researchers create quantum dots with single-atom precision June 30th, 2014

New Los Alamos Approach May Be Key to Quantum Dot Solar Cells With Real Gains in Efficiency: Nanoengineering Boosts Carrier Multiplication in Quantum Dots June 19th, 2014

MIPT-based researcher predicts new state of matter June 17th, 2014

Technology using microwave heating may impact electronics manufacture June 10th, 2014

Solar/Photovoltaic

From Narrow to Broad July 30th, 2014

Steam from the sun: New spongelike structure converts solar energy into steam July 21st, 2014

Making dreams come true: Making graphene from plastic? July 2nd, 2014

Shrinky Dinks close the gap for nanowires July 1st, 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