(Press-News.org) OAK RIDGE, Tenn., April 29, 2011 - With the creation of a 3-D nanocone-based solar cell platform, a team led by Oak Ridge National Laboratory's Jun Xu has boosted the light-to-power conversion efficiency of photovoltaics by nearly 80 percent.
The technology substantially overcomes the problem of poor transport of charges generated by solar photons. These charges -- negative electrons and positive holes -- typically become trapped by defects in bulk materials and their interfaces and degrade performance.
"To solve the entrapment problems that reduce solar cell efficiency, we created a nanocone-based solar cell, invented methods to synthesize these cells and demonstrated improved charge collection efficiency," said Xu, a member of ORNL's Chemical Sciences Division.
The new solar structure consists of n-type nanocones surrounded by a p-type semiconductor. The n-type nanoncones are made of zinc oxide and serve as the junction framework and the electron conductor. The p-type matrix is made of polycrystalline cadmium telluride and serves as the primary photon absorber medium and hole conductor.
With this approach at the laboratory scale, Xu and colleagues were able to obtain a light-to-power conversion efficiency of 3.2 percent compared to 1.8 percent efficiency of conventional planar structure of the same materials.
"We designed the three-dimensional structure to provide an intrinsic electric field distribution that promotes efficient charge transport and high efficiency in converting energy from sunlight into electricity," Xu said.
Key features of the solar material include its unique electric field distribution that achieves efficient charge transport; the synthesis of nanocones using inexpensive proprietary methods; and the minimization of defects and voids in semiconductors. The latter provides enhanced electric and optical properties for conversion of solar photons to electricity.
Because of efficient charge transport, the new solar cell can tolerate defective materials and reduce cost in fabricating next-generation solar cells.
"The important concept behind our invention is that the nanocone shape generates a high electric field in the vicinity of the tip junction, effectively separating, injecting and collecting minority carriers, resulting in a higher efficiency than that of a conventional planar cell made with the same materials," Xu said.
Research that forms the foundation of this technology was accepted by this year's Institute of Electrical and Electronics Engineers photovoltaic specialist conference and will be published in the IEEE Proceedings. The papers are titled "Efficient Charge Transport in Nanocone Tip-Film Solar Cells" and "Nanojunction solar cells based on polycrystalline CdTe films grown on ZnO nanocones."
###
The research was supported by the Laboratory Directed Research and Development program and the Department of Energy's Office of Nonproliferation Research and Engineering.
Other contributors to this technology are Sang Hyun Lee, X-G Zhang, Chad Parish, Barton Smith, Yongning He, Chad Duty and Ho Nyung Lee.
UT-Battelle manages ORNL for DOE's Office of Science.
NOTE TO EDITORS: You may read other press releases from Oak Ridge National Laboratory or learn more about the lab at http://www.ornl.gov/news. Additional information about ORNL is available at the sites below:
Twitter - http://twitter.com/oakridgelabnews
RSS Feeds - http://www.ornl.gov/ornlhome/rss_feeds.shtml
Flickr - http://www.flickr.com/photos/oakridgelab
YouTube - http://www.youtube.com/user/OakRidgeNationalLab
LinkedIn - http://www.linkedin.com/companies/oak-ridge-national-laboratory
Facebook - http://www.facebook.com/Oak.Ridge.National.Laboratory
New ORNL solar cell technology cranks up efficiency
2011-04-29
ELSE PRESS RELEASES FROM THIS DATE:
Gene therapy shows promise against age-related macular degeneration
2011-04-29
BOSTON (April 29, 2011) — A gene therapy approach using a protein called CD59, or protectin, shows promise in slowing the signs of age-related macular degeneration (AMD), according to a new in vivo study by researchers at Tufts University School of Medicine. Led by senior author Rajendra Kumar-Singh, PhD, the researchers demonstrated for the first time that CD59 delivered by a gene therapy approach significantly reduced the uncontrolled blood vessel growth and cell death typical of AMD, the most common cause of blindness in the elderly. The study was published on April ...
Credit Cards for Bad Credit - A User Guide 2011
2011-04-29
Online Credit Card Applications have made it easy to apply for Credit Cards for Bad Credit. People who rank low on their credit score were earlier shunned by issuers, who slotted them into the 'high risk' category. But, now, even instant approval credit cards for bad credit are easily available. Making more people want to apply for a quick and easy solution to their problems.
Financial experts suggest that people should take this opportunity to improve their credit rating. If used in the right way, a credit card can improve the financial ratings of a person, and can ...
International Dog Bite Prevention Challenge to Educate 50,000 Children
2011-04-29
Plans for the International Dog Bite Prevention Challenge are well underway. Doggone Safe challenged its presenters to visit schools and educate 50,000 children about dog safety in a single week. The Challenge will occur during Dog Bite Prevention Week (May 15-21, 2011). So far presenters have pledged to educate over 17,000 kids in six countries, six Canadian provinces and twenty six US states. Doggone Safe has applied to be considered for a Guinness Record attempt for the Challenge.
Half of all children are bitten by a dog and most of the time the biter is the family ...
Prompt Proofing Blog Post: How to Improve Your Writing: Part 4
2011-04-29
This is the fourth of a six-part series on improving your writing style. Whether you write for business or academic purposes, there are a few golden rules that will help you sharpen up your prose.
Part 4: Limit use of cliches
Phrases become 'cliche' when they are overused. Writing that is full of cliches is annoying to read and suggests laziness on the part of the author. Once clever, these phrases have now become trite and should be replaced with a more concise phrase, or even omitted altogether.
Consider the following, and their alternatives:
1. News of the ...
GstarCAD Founders Invited to Attend the Centenary Celebration Ceremony of Tsinghua University
2011-04-28
Tsinghua University, one of China's foremost higher learning institutions, hold the Centenary Celebration Ceremony at the Great Hall of People on April 24, attended by Chinese President Hu Jintao, Premier Wen Jiabao and other state and Communist Party leaders with Three Nobel Prize winners, Lee Tsung-dao, Yang Chen-ning and Lee Yuan-tseh all as Tsinghua Alumni. President of Gstarsoft Co., Ltd. Lu Xiang, Vice President Huang Meiyu and Pan Li, etc., who are founders of GstarCAD, were also invited to attend the ceremony on behalf of Tsinghua alumni from computer technology ...
Maybank MoneyTree Young Entrepreneur Startup (YES 3) Challenge - Red Carpet
2011-04-28
The Maybank MoneyTree Young Entrepreneur Startup Challenge "YES 3 Red Carpet" party was held on Friday, 15th April 2011 at the Eastin Hotel, Petaling Jaya. The YES 3 Red Carpet party was a cocktail party to celebrate the entrepreneurial journey of the YES 3 finalists and for the grand finale, the unveiling of the YES 3 Grand Prize Winner, Team FutsalEx, from Universiti Teknologi Mara (UiTM).
The Finalists of the YES Challenge were ushered in ala Celebrity style where they were accompanied by an entourage and bodyguards before being greeted by the sound of applause ...
4ipnet Unveils EAP300 3x3 MIMO 11n/a/b/g Access Point with Proprietary Press-n-Connect Technology
2011-04-28
4ipnet, Inc., a provider of wireless network security and management products, today introduced its high-end 802.11n/a/b/g EAP300 Indoor Access Point, the most affordable access point in the market.
The EAP300 is cost effective for maximum deployment flexibility, and provides a wide range of advanced features to deliver wire-like performance at data speed rating up to 300Mbps per radio. With its IP50 dust-proof metal housing, EAP300 packs 3x3 transmit/receive MIMO antennae and dual band 2.4-GHz / 5 GHz MIMO radios, making it the perfect choice for wireless connectivity ...
Rate Speeches Launches Website For Rating And Evaluating Public Speaking, Speeches, And Speakers For Immediate Release
2011-04-28
The Rate Speeches website allows people to find ratings and to add ratings of speeches, presentations, speakers, and presenters. The website also gives public speaking and presentation skills experts online tools for evaluating speeches and presentations.
Before attending a speech or a presentation by a speaker, prospective attendees can check the rating of the speaker and prior speeches by that speaker to decide whether to attend or not. Audience members can add and rate speakers and speeches to share their experiences with others and also to give feedback to the speaker. ...
DPFG, Inc. Releases The Spring 2011 Edition Of The DPFG Report
2011-04-28
DPFG, INC. RELEASES THE SPRING 2011 EDITION OF THE DPFG REPORT
DPFG, Inc. is pleased to announce the release of the Spring 2011 Edition of the DPFG Report ("Report"). The Report is our electronic corporate newsletter that was created to help keep you up to date on the latest seasonal and educational topics that matter most to the real estate industry.
We encourage you to pass on the newsletter to your co-workers and any other colleagues that could benefit from reading the Report. We also hope that you take a moment or two to provide any feedback that you ...
Florida based Didrick Medical Inc Appoints Aasim Saied as New CEO
2011-04-28
Didrick Medical, a leading provider of cutting edge prosthetic fingers, has appointed Aasim Saied its Chairman. In this role, Saied will be structuring Didrick Medical for a global launch. Florida based Didrick Medical has completed the development of the X-System - an interchangeable series of components that can be configured into more than 500 positions to function as artificial fingers for finger amputees. The X-System is the only product that restores function to individuals missing a portion or all of any finger or fingers while having their palm still intact.
Saied ...