Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fraunhofer ISE Achieves New World Record for Both Sides-Contacted Silicon Solar Cells

15.09.2015

25.1 Percent Efficiency with TOPCon Technology

The Fraunhofer Institute for Solar Energy Systems ISE has set a new efficiency record for silicon solar cells. For the first time, an efficiency of 25.1 percent has been measured for a both sides-contacted silicon solar cell. Having a simple rear side contact without any patterning, this type of solar cell converts one quarter of the incident sunlight into electricity. The new concept for the solar cell rear side holds great potential for further increases in efficiency.


Fraunhofer ISE achieves new world record for both sides-contacted silicon solar cell: TOPCon technology makes 25.1 percent efficiency possible.

© Fraunhofer ISE


TEM-image (Transmission Electron Microscope) showing TOPCon structure developed at Fraunhofer ISE for both sides-contacted silicon solar cells.

© Fraunhofer ISE

This record achieved by Fraunhofer ISE is the highest efficiency achieved to date for both sides-contacted silicon solar cells, characterized by having metal contacts on both the front and rear sides. This solar cell at 25.1 percent efficiency features a novel concept, namely a full-area passivated back contact.

“To improve the solar cell efficiency, the focus has been on increasingly complex solar cell structures up to now,” explains Dr. Martin Hermle, Head of the High Efficiency Solar Cells department at Fraunhofer ISE. “The biggest advantage of our new concept is that we can now contact the entire rear cell surface without patterning. Compared to the high-efficiency solar cell structures presently in use, we offer both a simplified manufacturing process and higher efficiencies at the same time,” says Hermle.

With the so-called TOPCon (Tunnel Oxide Passivated Contact) technology, developed by Fraunhofer ISE, metal contacts are applied to the rear side without patterning. To achieve this, the Fraunhofer researchers developed a selective passivated contact made of tunnel oxide that enables majority charge carriers to pass and prevents the minority carriers from recombining.

The thickness of the intermediate passivation layer is reduced to one or two nanometers, allowing the charge carriers to “tunnel” through it. Subsequently, a thin coating of highly doped silicon is deposited over the entire layer of ultra-thin tunnel oxide. This novel combination of layers allows electrical current to flow out of the cell with nearly zero loss.

In the photovoltaics industry, the majority of solar cells have an aluminum-alloyed back contact covering the entire rear side. This type of contact, however, limits the efficiency. Therefore, the industry currently retrofits their production to incorporate the PERC (Passivated Emitter Rear Cell) technology in order to increase the solar cell efficiency.

With PERC technology, only a small area on the rear side is contacted in order to reduce recombination. PERC, however, requires additional patterning steps and leads to longer current conduction paths in the silicon wafer. TOPCon, on the other hand, offers a possible approach to reduce these loss mechanisms and increase the efficiency.

“With TOPCon, we have developed a pioneering technology to increase the efficiency of silicon solar cells,” says Prof. Stefan Glunz, Division Director of Solar Cells – Development and Characterization. “At 25.1% efficiency, we are the first research institute to cross the 25 percent mark with an evolutionary further development for both sides-contacted solar cells and to close the gap on the world record efficiency for back contacted solar cells,” adds Glunz.

The team of Dr. Martin Hermle has been working on the TOPCon concept for about three years. The scientists in the team have succeeded in continually increasing the solar cell efficiency using this technology. With their latest result, they have surpassed the 25 percent mark. The research was funded within the project FORTES from the German Federal Ministry for Economic Affairs and Energy and U.S. Department of Energy, Energy Efficiency and Renewable Energy Program, under Award Number DE-EE0006336.

EU PVSEC: Come hear our presentation on this topic!

On Tuesday, September 15, 2015, Prof. Stefan Glunz, Division Director of “Solar Cells – Development and Characterization” will hold a plenary talk on this topic at the European Photovoltaic Conference (EU PVSEC) in Hamburg. The title of the talk is “The Irresistible Charm of a Simple Current Flow Pattern – Approaching 25 % with a Solar Cell Featuring a Full-Area Back Contact” (Plenary Session 2BP.1 from 10:30-12:10 a.m.)

Weitere Informationen:

http://www.ise.fraunhofer.de

Karin Schneider | Fraunhofer-Institut für Solare Energiesysteme ISE

More articles from Power and Electrical Engineering:

nachricht Waste from paper and pulp industry supplies raw material for development of new redox flow batteries
12.10.2017 | Johannes Gutenberg-Universität Mainz

nachricht Low-cost battery from waste graphite
11.10.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

Im Focus: New nanomaterial can extract hydrogen fuel from seawater

Hybrid material converts more sunlight and can weather seawater's harsh conditions

It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...

Im Focus: Small collisions make big impact on Mercury's thin atmosphere

Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers.

Recent modeling along with previously published results from NASA's MESSENGER spacecraft -- short for Mercury Surface, Space Environment, Geochemistry and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Taking screening methods to the next level

17.10.2017 | Life Sciences

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

‘Find the Lady’ in the quantum world

17.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>