Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Quantum manipulation power for quantum information processing gets a boost: Improving the efficiency of quantum heat engines involves reducing the number of photons in a cavity, ultimately impacting quantum manipulation power October 14th, 2017

Laboratories

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Injecting electrons jolts 2-D structure into new atomic pattern: Berkeley Lab study is first to show potential of energy-efficient next-gen electronic memory October 13th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Discoveries

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Announcements

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

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

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Energy

New nanomaterial can extract hydrogen fuel from seawater: Hybrid material converts more sunlight and can weather seawater's harsh conditions October 4th, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 2017

Industrial

Injecting electrons jolts 2-D structure into new atomic pattern: Berkeley Lab study is first to show potential of energy-efficient next-gen electronic memory October 13th, 2017

A flexible new platform for high-performance electronics September 29th, 2017

GLOBALFOUNDRIES Announces Availability of Embedded MRAM on Leading 22FDX® FD-SOI Platform: Advanced embedded non-volatile memory solution delivers ‘connected intelligence’ by expanding SoC capabilities on the 22nm process node September 20th, 2017

Researchers printed graphene-like materials with inkjet August 17th, 2017

Quantum Dots/Rods

Quantum communications bend to our needs: By changing the wavelengths of entangled photons to those used in telecommunications, researchers see quantum technology take a major leap forward September 28th, 2017

Band Gaps, Made to Order: Engineers create atomically thin superlattice materials with precision September 26th, 2017

New approach on research and design for CQD catalysts in World Scientific NANO August 2nd, 2017

Coupling a nano-trumpet with a quantum dot enables precise position determination July 14th, 2017

Solar/Photovoltaic

New nanomaterial can extract hydrogen fuel from seawater: Hybrid material converts more sunlight and can weather seawater's harsh conditions October 4th, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 2017

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