Oligomer-based organic PV cell hits 9.8% efficiency

Heliatek GmbH manufactured organic solar cells with cell power conversion efficiency of 9.8%, certified by Fraunhofer ISE CalLab. The technology is a 1.1 cm² tandem cell manufactured with an oligomer-material low-temperature deposition process.

December 5, 2011 — High-end solar photovoltaics company Heliatek GmbH manufactured organic solar cells with cell power conversion efficiency of 9.8%, certified by Fraunhofer ISE CalLab. The technology is a 1.1 cm² tandem cell manufactured with an oligomer-material low-temperature deposition process.

Heliatek expects a panel with a size factor >120 using the same technology will have efficiency over 9% for the active module area.
 
Heliatek develops and synthesizes the light-capturing molecules in-house. Using patented tandem cell technology, it is possible to absorb a very broad solar spectrum using 500nm-thick organic layers. The company was able to optimize the absorber layer system of the 9.8% efficiency cells through synthetizing appropriate materials. By changes to the deposition process, cell morphology was significantly improved, leading to an increase in power output and in fill factor.

Heliatek is focused on improving the deposition of small molecules with low-temperature processes, said Dr. Martin Pfeiffer, co-founder and CTO of Heliatek, saying the idea is similar to manufacturing methods used commonly for organic LEDs (OLEDs). Heliatek operates chemistry and physics research departments to discover materials quality and cell design improvements simultaneously.

Heliatek GmbH hit 8.3% efficiency a year ago on an active surface of 1.1cm², and was at 6% in 2009. The new record, 9.8% conversion efficiency, is on a level with amorphous silicon (a-Si) solar cells, said Pfeiffer.
 
The new method and materials will gradually be integrated into Heliatek?s manufacturing process after the scheduled start of production in H2 2012. Heliatek plans to use a low-temperature roll-to-toll process to fabricate solar panels. Low process temperatures allow for the use of plastic film as substrate material.
 
“The next step on our way to 15% [efficiency] will be a cell with over 10% efficiency sometime next year,” said Thibaud Le Séguillon, CEO of Heliatek. “After our third investment round scheduled for 2012 – during which we plan to raise some ?50 million in new capital from current and new investors – we plan to expand our production capacity with additional manufacturing lines. This will allow us to market our high-performance panels into new areas, such as windows and facades for BIPV.”

Heliatek acknowledges comprehensive financial support of its R&D projects by the German Federal Ministry of Education and Research (BMBF) under project numbers 13N9869 and 13N9716, as well as the European Regional Development Fund (ERDF) and Freistaat Sachsen under project number 71070.
 
Dr. Martin Pfeiffer (CTO of Heliatek GmbH), together with his fellow researchers Prof. Karl Leo (Director of IAPP) and Dr. Jan Blochwitz-Nimoth (Novaled AG), has been nominated for the 2011 Deutschen Zukunftspreis for successful research in the field of organic electronics.

Heliatek was named a Champion Company of Photovoltaics in the 2011 Champions issue of Photovoltaics World.

Heliatek provides high-end solar PV technology, spun-off in 2006 from the Technical University of Dresden (IAPP) and the University of Ulm. More information can be found at www.heliatek.com.

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