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 Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH

nachricht To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>