Featured Research

from universities, journals, and other organizations

Understanding the functioning of a new type of solar cell

Date:
January 21, 2014
Source:
Ecole Polytechnique Fédérale de Lausanne
Summary:
Scientists have uncovered the mechanism by which novel, revolutionary solar cells based on lead iodide perovskite light-absorbing semiconductor transfer electrons along their surface. The finding shows these devices constitute a new type of solar cells and open the way to the design of photovoltaic converters with improved efficiency.

Photovoltaic energy conversion offers one of the best means for the future of renewable energy in the world. The efficiency of solar cells depends heavily upon the light-absorbing materials they use. Photovoltaic systems based on lead halide perovskite are a new, revolutionary type of device with efficiencies currently exceeding 16%. However, a detailed description of how these solar cells turn light into electrical current is still lacking. Publishing in Nature Photonics, scientists from EPFL have investigated how the generated electrical charge travels across the perovskite surface of solar cells built with different architectures.

Related Articles


Lead halide perovskites are materials that have recently attracted an immense interest, as solar cells based on these semiconductors demonstrate very high conversion efficiencies and an unsurpassed cell voltage of more than 1 V. However, it is not entirely clear how they work. A better understanding of their functioning mechanisms would help improve them in the future or even open up novel technologies with increased efficiency.

The groups of Michael Grätzel and Jaques E. Moser at EPFL, working with the Institute for Solar Fuels in Berlin, have used time-resolved spectroscopy techniques to determine how charges move across perovskite surfaces. The researchers worked on various cell architectures, using either semiconducting titanium dioxide or insulating aluminum trioxide films. Both porous films were impregnated with lead iodide perovskite (CH3NH3PbI3) and an organic "hole-transporting material," which helps extracting positive charges following light absorption. The time-resolved techniques included ultrafast laser spectroscopy and microwave photoconductivity.

The results showed two main dynamics. First, that charge separation, the flow of electrical charges after sunlight reaches the perovskite light-absorber, takes place through electron transfer at both junctions with titanium dioxide and the hole-transporting material on a sub-picosecond timescale. Secondly, the researchers found that charge recombination was significantly slower for titanium oxide films rather than aluminum ones. Charge recombination is a detrimental process wasting the converted energy into heat and thus reducing the overall efficiency of the solar cell.

The authors state that lead halide perovskites constitute unique semiconductor materials in solar cells, allowing ultrafast transfer of electrons and positive charges at two junctions simultaneously and transporting both types of charge carriers quite efficiently. In addition, their findings show a clear advantage of the architecture based on titanium dioxide films and hole-transporting materials.


Story Source:

The above story is based on materials provided by Ecole Polytechnique Fédérale de Lausanne. Note: Materials may be edited for content and length.


Journal Reference:

  1. Arianna Marchioro, Joël Teuscher, Dennis Friedrich, Marinus Kunst, Roel van de Krol, Thomas Moehl, Michael Grätzel, Jacques-E. Moser. Unravelling the mechanism of photoinduced charge transfer processes in lead iodide perovskite solar cells. Nature Photonics, 2014; DOI: 10.1038/nphoton.2013.374

Cite This Page:

Ecole Polytechnique Fédérale de Lausanne. "Understanding the functioning of a new type of solar cell." ScienceDaily. ScienceDaily, 21 January 2014. <www.sciencedaily.com/releases/2014/01/140121113449.htm>.
Ecole Polytechnique Fédérale de Lausanne. (2014, January 21). Understanding the functioning of a new type of solar cell. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2014/01/140121113449.htm
Ecole Polytechnique Fédérale de Lausanne. "Understanding the functioning of a new type of solar cell." ScienceDaily. www.sciencedaily.com/releases/2014/01/140121113449.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