Navigation Links
Elusive 'hot' electrons captured in ultra-thin solar cells

CHESTNUT HILL, MA (12/11/2009) Boston College researchers have observed the "hot electron" effect in a solar cell for the first time and successfully harvested the elusive charges using ultra-thin solar cells, opening a potential avenue to improved solar power efficiency, the authors report in the current online edition of Applied Physics Letters.

When light is captured in solar cells, it generates free electrons in a range of energy states. But in order to snare these charges, the electrons must reach the bottom of the conduction band. The problem has been that these highly energized "hot" electrons lose much of their energy to heat along the way.

Hot electrons have been observed in other devices, such as semiconductors. But their high kinetic energy can cause these electrons, also known as "hot carriers," to degrade a device. Researchers have long theorized about the benefits of harnessing hot electrons for solar power through so-called "3rd generation" devices.

By using ultrathin solar cells a film fewer than 30 nanometers thick the team developed a mechanism able to extract hot electrons in the moments before they cool effectively opening a new "escape hatch" through which they typically don't travel, said co-author Michael J. Naughton, the Evelyn J. and Robert A. Ferris Professor of Physics at Boston College.

The team's success centered on minimizing the environment within which the electrons are able to escape, said Professor of Physics Krzysztof Kempa, lead author of the paper.

Kempa compared the challenge to trying to heat a swimming pool with a pot of boiling water. Drop the pot into the center of the pool and there would be no change in temperature at the edge because the heat would dissipate en route. But drop the pot into a sink filled with cold water and the heat would likely raise the temperature in the smaller area.

"We have shrunk the size of the solar cell by making it thin," Kempa said. "In doing so, we are bringing these hot electrons closer to the surface, so they can be collected more readily. These electrons have to be captured in less than a picosecond, which is less than one trillionth of a second."

The ultrathin cells demonstrated overall power conversion efficiency of approximately 3 percent using absorbers one fiftieth as thick as conventional cells. The team attributed the gains to the capture of hot electrons and an accompanying reduction in voltage-sapping heat. The researchers acknowledged the film's efficiency is limited by the negligible light collection of ultra-thin junctions. However, combining the film with better light-trapping technology such as nanowire structures could significantly increase efficiency in an ultra-thin hot electron solar cell technology.


Contact: Ed Hayward
Boston College

Related biology technology :

1. Researchers measure elusive repulsive force from quantum fluctuations
2. Prototype NIST method detects and measures elusive hazards
3. BioSpace and BayBio Launch 11th Edition of Biotech Bay(TM) Hotbed Map Campaign
4. BioSpace, 2008 BIO International Convention and BIOCOM Launch 9th Edition of Biotech Beach Hotbed Map Campaign
5. Glycominds Joins Biomolecular Photonic (BMP) Consortium to Develop New Molecular Imaging Technique
6. An Uncommon Eye: Photography Exhibit by Biotechnology Executive at BHCC Gallery
7. Thermo Fisher Scientific Acquires Leader in Micro-Volume Spectrophotometers, NanoDrop Technologies
8. Epeius Biotechnologies Leads With Keynote Address on the Advent of Pathotropic Medicine for Cancer at the Global Pharma R&D Summit Conference in Boston MA
9. Danish Hotspot in Personalized Medicine
10. 3-D photonic crystals will revolutionize telecommunications
11. BioSpace Launches 2nd Edition of Southern Pharm(TM) Hotbed Campaign
Post Your Comments:
(Date:6/23/2016)... ... 2016 , ... UAS LifeSciences, one of the leading manufacturers ... Probiotics, into Target stores nationwide. The company, which has been manufacturing high quality ... list of well-respected retailers. This list includes such fine stores as Whole Foods, ...
(Date:6/23/2016)... ... June 23, 2016 , ... Charm Sciences, Inc. ... test has received AOAC Research Institute approval 061601. , “This is another AOAC-RI ... stated Bob Salter, Vice President of Regulatory and Industrial Affairs. “The Peel Plate ...
(Date:6/23/2016)... ... , ... STACS DNA Inc., the sample tracking software company, today announced that ... joined STACS DNA as a Field Application Specialist. , “I am thrilled that ... of STACS DNA. “In further expanding our capacity as a scientific integrator, Hays brings ...
(Date:6/23/2016)... 2016 On Wednesday, June 22, 2016, ... 0.22%; the Dow Jones Industrial Average edged 0.27% lower to ... down 0.17%. has initiated coverage on the following equities: ... (NASDAQ: NKTR ), Aralez Pharmaceuticals Inc. (NASDAQ: ... BIND ). Learn more about these stocks by accessing their ...
Breaking Biology Technology:
(Date:6/2/2016)... Perimeter Surveillance & Detection Systems, ... Infrastructure, Support & Other Service  The latest ... comprehensive analysis of the global Border Security market ... of $17.98 billion in 2016. Now: In ... in software and hardware technologies for advanced video surveillance. ...
(Date:5/12/2016)... DALLAS , May 12, 2016 ... has just published the overview results from the Q1 ... of the recent wave was consumers, receptivity to a ... wearables data with a health insurance company. ... choose to share," says Michael LaColla , CEO ...
(Date:4/26/2016)... LONDON , April 26, 2016 ... EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... a partnership to integrate the Onegini mobile security ... (Logo: ) The ... enhanced security to access and transact across channels. ...
Breaking Biology News(10 mins):