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 Engineers program tiny robots to move, think like insects
15.12.2017 | Cornell University

nachricht Electromagnetic water cloak eliminates drag and wake
12.12.2017 | Duke University

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: Error-free into the Quantum Computer Age

A study carried out by an international team of researchers and published in the journal Physical Review X shows that ion-trap technologies available today are suitable for building large-scale quantum computers. The scientists introduce trapped-ion quantum error correction protocols that detect and correct processing errors.

In order to reach their full potential, today’s quantum computer prototypes have to meet specific criteria: First, they have to be made bigger, which means...

Im Focus: Search for planets with Carmenes successful

German and Spanish researchers plan, build and use modern spectrograph

Since 2016, German and Spanish researchers, among them scientists from the University of Göttingen, have been hunting for exoplanets with the “Carmenes”...

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

The body's street sweepers

18.12.2017 | Life Sciences

Fast flowing heat in layered material heterostructures

18.12.2017 | Materials Sciences

Life on the edge prepares plants for climate change

18.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>