Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Structure Of Plastic Solar Cells Impedes Their Efficiency

08.10.2010
A team of researchers from North Carolina State University and the U.K. has found that the low rate of energy conversion in all-polymer solar-cell technology is caused by the structure of the solar cells themselves. They hope that their findings will lead to the creation of more efficient solar cells.

Polymeric solar cells are made of thin layers of interpenetrating structures from two different conducting plastics and are increasingly popular because they are both potentially cheaper to make than those currently in use and can be “painted” or printed onto a variety of surfaces, including flexible films made from the same material as most soda bottles.

However, these solar cells aren’t yet cost-effective to make because they only have a power conversion rate of about three percent, as opposed to the 15 to 20 percent rate in existing solar technology.

“Solar cells have to be simultaneously thick enough to absorb photons from the sun, but have structures small enough for that captured energy – known as an exciton – to be able to travel to the site of charge separation and conversion into the electricity that we use,” says Dr. Harald Ade, professor of physics and one of the authors of a paper describing the research. “The solar cells capture the photons, but the exciton has too far to travel, the interface between the two different plastics used is too rough for efficient charge separation, and its energy gets lost.”

The researchers’ results appear online in Advanced Functional Materials and Nano Letters.

In order for the solar cell to be most efficient, Ade says, the layer that absorbs the photons should be around 150-200 nanometers thick (a nanometer is thousands of times smaller than the width of a human hair). The resulting exciton, however, should only have to travel a distance of 10 nanometers before charge separation. The way that polymeric solar cells are currently structured impedes this process.

Ade continues, “In the all-polymer system investigated, the minimum distance that the exciton must travel is 80 nanometers, the size of the structures formed inside the thin film. Additionally, the way devices are currently manufactured, the interface between the structures isn’t sharply defined, which means that the excitons, or charges, get trapped. New fabrication methods that provide smaller structures and sharper interfaces need to be found.”

Ade and his team plan to look at different types of polymer-based solar cells to see if their low efficiencies are due to this same structural problem. They hope that their data will lead chemists and manufacturers to explore different ways of putting these cells together to increase efficiency.

“Now that we know why the existing technology doesn’t work as well as it could, our next steps will be in looking at physical and chemical processes that will correct for those problems. Once we get a baseline of efficiency, we can redirect research and manufacturing efforts.”

The research was funded by a grant by the U.S. Department of Energy and the Engineering and Physical Sciences Research Council, U.K. The Department of Physics is part of NC State’s College of Physical and Mathematical Sciences.

Tracey Peake | EurekAlert!
Further information:
http://www.ncsu.edu
http://news.ncsu.edu/releases/ade/

More articles from Materials Sciences:

nachricht Robust and functional – surface finishing by suspension spraying
19.09.2017 | Fraunhofer-Institut für Keramische Technologien und Systeme IKTS

nachricht Graphene and other carbon nanomaterials can replace scarce metals
19.09.2017 | Chalmers University of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>