Featured Research

from universities, journals, and other organizations

Magnetic fingerprints of interface defects in silicon solar cells detected

Date:
March 27, 2013
Source:
Helmholtz Association of German Research Centres
Summary:
Using a highly sensitive method of measurement, physicists have managed to localize defects in amorphous/crystalline silicon heterojunction solar cells. Now, for the first time ever, using computer simulations, the scientists were able to determine the defects' exact locations and assign them to certain structures within the interface between the amorphous and crystalline phases.

Using a highly sensitive method of measurement, HZB physicists have managed to localize defects in amorphous/crystalline silicon heterojunction solar cells. Now, for the first time ever, using computer simulations at Paderborn University, the scientists were able to determine the defects' exact locations and assign them to certain structures within the interface between the amorphous and crystalline phases.
Credit: HZB / University Paderborn

Using a highly sensitive method of measurement, HZB physicists have managed to localize defects in amorphous/crystalline silicon heterojunction solar cells. Now, for the first time ever, using computer simulations at Paderborn University, the scientists were able to determine the defects' exact locations and assign them to certain structures within the interface between the amorphous and crystalline phases.

Related Articles


In theory, silicon-based solar cells are capable of converting up to 30 percent of sunlight to electricity -- although, in reality, the different kinds of loss mechanisms ensure that even under ideal lab conditions it does not exceed 25 %. Advanced heterojunction cells shall affront this problem: On top of the wafer's surface, at temperatures below 200 °C, a layer of 10 nanometer disordered (amorphous) silicon is deposited. This thin film is managing to saturate to a large extent the interface defects and to conduct charge carriers out of the cell. Heterojunction solar cells have already high efficiency factors up to 24,7 % -- even in industrial scale. However, scientists had until now only a rough understanding of the processes at the remaining interface defects.

Now, physicists at HZB's Institute for Silicon Photovoltaics have figured out a rather clever way for detecting the remaining defects and characterizing their electronic structure. "If electrons get deposited on these defects, we are able to use their spin, that is, their small magnetic moment, as a probe to study them," Dr. Alexander Schnegg explains. With the help of EDMR, electrically detected magnetic resonance, an ultrasensitive method of measurement, they were able to determine the local defects' structure by detecting their magnetic fingerprint in the photo current of the solar cell under a magnetic field and microwave radiation.

Theoretical physicists of Paderborn University could compare these results with quantum chemical computer simulations, thus obtaining information about the defects' positions within the layers and the processes they are involved to decrease the cells' efficiency. "We basically found two distinct families of defects," says Dr. Uwe Gerstmann from Paderborn University, who collaborates with the HZB Team in a program sponsored by Deutsche Forschungsgemeinschaft (DFG priority program 1601). "Whereas in the first one, the defects are rather weakly localized within the amorphous layer, a second family of defects is found directly at the interface, but in the crystalline silicon."

For the first time ever the scientists have succeeded at directly detecting and characterizing processes with atomic resolution that compromise these solar cells' high efficiency. The cells were manufactured and measured at the HZB; the numerical methods were developed at Paderborn University. "We can now apply these findings to other types of solar cells in order to optimize them further and to decrease production costs," says Schnegg.


Story Source:

The above story is based on materials provided by Helmholtz Association of German Research Centres. Note: Materials may be edited for content and length.


Journal Reference:

  1. B. M. George, J. Behrends, A. Schnegg, T. F. Schulze, M. Fehr, L. Korte, B. Rech, K. Lips, M. Rohrmόller, E. Rauls, W. G. Schmidt, U. Gerstmann. Atomic Structure of Interface States in Silicon Heterojunction Solar Cells. Physical Review Letters, 2013; 110 (13) DOI: 10.1103/PhysRevLett.110.136803

Cite This Page:

Helmholtz Association of German Research Centres. "Magnetic fingerprints of interface defects in silicon solar cells detected." ScienceDaily. ScienceDaily, 27 March 2013. <www.sciencedaily.com/releases/2013/03/130327104151.htm>.
Helmholtz Association of German Research Centres. (2013, March 27). Magnetic fingerprints of interface defects in silicon solar cells detected. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2013/03/130327104151.htm
Helmholtz Association of German Research Centres. "Magnetic fingerprints of interface defects in silicon solar cells detected." ScienceDaily. www.sciencedaily.com/releases/2013/03/130327104151.htm (accessed October 24, 2014).

Share This



More Matter & Energy News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Printed Instruments Make Sweet Music in Sweden

3D Printed Instruments Make Sweet Music in Sweden

Reuters - Innovations Video Online (Oct. 23, 2014) — Students from Lund University's Malmo Academy of Music are believed to be the world's first band to all use 3D printed instruments. The guitar, bass guitar, keyboard and drums were built by Olaf Diegel, professor of product development, who says 3D printing allows musicians to design an instrument to their exact specifications. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins