Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. Solar Energy News .




SOLAR DAILY
NRL Designs Multi-Junction Solar Cell to Break Efficiency Barrier
by Staff Writers
Arlington VA (SPX) Jan 17, 2013


Schematic diagram of a multi-junction (MJ) solar cell formed from materials lattice-matched to InP and achieving the bandgaps for maximum efficiency. (Photo: U.S. Naval Research Laboratory). For a larger version of this image please go here.

U.S. Naval Research Laboratory scientists in the Electronics Technology and Science Division, in collaboration with the Imperial College London and MicroLink Devices, Inc., Niles, Ill., have proposed a novel triple-junction solar cell with the potential to break the 50 percent conversion efficiency barrier, which is the current goal in multi-junction photovoltaic development.

"This research has produced a novel, realistically achievable, lattice-matched, multi-junction solar cell design with the potential to break the 50 percent power conversion efficiency mark under concentrated illumination," said Robert Walters, Ph.D., NRL research physicist.

"At present, the world record triple-junction solar cell efficiency is 44 percent under concentration and it is generally accepted that a major technology breakthrough will be required for the efficiency of these cells to increase much further."

In multi-junction (MJ) solar cells, each junction is 'tuned' to different wavelength bands in the solar spectrum to increase efficiency. High bandgap semiconductor material is used to absorb the short wavelength radiation with longer wavelength parts transmitted to subsequent semiconductors.

In theory, an infinite-junction cell could obtain a maximum power conversion percentage of nearly 87 percent. The challenge is to develop a semiconductor material system that can attain a wide range of bandgaps and be grown with high crystalline quality.

By exploring novel semiconductor materials and applying band structure engineering, via strain-balanced quantum wells, the NRL research team has produced a design for a MJ solar cell that can achieve direct band gaps from 0.7 to 1.8 electron volts (eV) with materials that are all lattice-matched to an indium phosphide (InP) substrate.

"Having all lattice-matched materials with this wide range of band gaps is the key to breaking the current world record" adds Walters. "It is well known that materials lattice-matched to InP can achieve band gaps of about 1.4 eV and below, but no ternary alloy semiconductors exist with a higher direct band-gap."

The primary innovation enabling this new path to high efficiency is the identification of InAlAsSb quaternary alloys as a high band gap material layer that can be grown lattice-matched to InP.

Drawing from their experience with Sb-based compounds for detector and laser applications, NRL scientists modeled the band structure of InAlAsSb and showed that this material could potentially achieve a direct band-gap as high as 1.8eV.

With this result, and using a model that includes both radiative and non-radiative recombination, the NRL scientists created a solar cell design that is a potential route to over 50 percent power conversion efficiency under concentrated solar illumination.

Recently awarded a U.S. Department of Energy (DoE), Advanced Research Projects Agency-Energy (ARPA-E) project, NRL scientists, working with MicroLink and Rochester Institute of Technology, Rochester, N.Y., will execute a three year materials and device development program to realize this new solar cell technology.

Through a highly competitive, peer-reviewed proposal process, ARPA-E seeks out transformational, breakthrough technologies that show fundamental technical promise but are too early for private-sector investment.

These projects have the potential to produce game-changing breakthroughs in energy technology, form the foundation for entirely new industries, and to have large commercial impacts.

.


Related Links
Naval Research Laboratory
All About Solar Energy at SolarDaily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





SOLAR DAILY
Device Tosses Out Unusable PV Wafers
Golden CO (SPX) Jan 17, 2013
Silicon wafers destined to become photovoltaic (PV) cells can take a bruising through assembly lines, as they are oxidized, annealed, purified, diffused, etched, and layered to reach their destinies as efficient converters of the sun's rays into useful electricity. All those refinements are too much for 5% to 10% of the costly wafers. They have micro-cracks left over from incomplete wafer ... read more


SOLAR DAILY
Marginal land can help meet US biofuel target: study

US Ag Sec Visits Renmatix For Plant-To-Sugar Facility Commissioning

Synthesis Energy Achieves First Methanol Production at Yima JV

Lower nitrogen losses with perennial biofuel crops

SOLAR DAILY
Robot Spheres in zero-gravity action

2013 FIRST Robotics Kick-Off Event

Crew Prepares for Student Robotics Competition

LS3 Four-Legged Robot Plays Follow the Leader

SOLAR DAILY
Japan plans world's largest wind farm

China revs up wind power amid challenges

Algonquin Power Buys 109 MW Shady Oaks Wind Power Facility

British group pans wind farm compensation

SOLAR DAILY
Does everyone think someone else should drive a green car?

Lexus to launch hybrid sedan in Japan, Europe

Jeep to build cars in China with GAC

Nissan cuts price of electric Leaf

SOLAR DAILY
Chavez aides assure citizens of continuity

Fusion helped by collision science

Four Chinese abducted in Sudan's Darfur freed: UNAMID

North Sea oil pipeline system shut after platform leak: operator

SOLAR DAILY
Turkey and France to resume nuclear plant talks: minister

Regulator wants more info before clearing Belgian reactors

Westinghouse Achieves Milestones For World's First Ap1000 Nuclear Power Plants

Malaysia nuclear plan delayed: official

SOLAR DAILY
Renewable energy on increase but 2030 target in doubt

First world atlas on renewable energy launched

Major cuts to surging CO2 emissions are needed now, not down the road

Three new state-of-the-art power plants improve efficiency, reduce emissions

SOLAR DAILY
Bengali forests are fading away

Three-wheeler rally flagged off for Indonesia forests

Mangrove loss threatens Bengal tiger

Greeks ravage forests to heat homes




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement