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nanotimes Research

Solar Cells I // Organic Solar Cell Architecture Sets New Performance Level

T

he Belgian research centre imec, together with Plextronics and Solvay (SOLB.BE), presented at

the European Photovoltaic Solar Energy Conference and Exhibition (PVSEC) in Hamburg, Germany, an organic polymer-based single junction solar cell with 6.9% performance in an innovative inverted device stack. Combining imec‘s scalable inverted device architecture and Plextronics‘ polymers, new levels of cell efficiency were achieved. The polymer was also integrated into a module resulting in excel- lent module level efficiencies of 5% for an aperture area of 25cm².

The dedicated inverted bulk heterojunction archi- tecture developed by imec improved the device performance by at least 0.5% over standard architec- tures used for organic solar cells. In the active layer, a new buffer layer was introduced to optimize the light management in the device. Imec’s innovative device architecture, combined with Plextronics’ low band-gap p-type polymer with a fullerene derivate, resulted in a stabilized certified conversion efficiency of 6.9%, which is the highest performance obtained for this polymer material and, to our knowledge, the highest efficiency reported for inverted architectures. In this new inverted device architecture, similar per- formance boosts have also been achieved for other polymer materials. The module level efficiencies confirm the suitability towards upscaling.

Tom Aernouts, R&D Team Leader Organic Photo- voltaics at imec: “We are delighted to present these excellent results, achieved by combining imec’s ex- pertise and knowhow in organic photovoltaics R&D with Plextronics’ innovative material. With further optimizations to the material as well as to the archi- tecture, for example by introducing a multi-junction featuring different layers of different polymers each capturing another part of the light spectrum, we en- vision organic solar cell lifetimes of over 10 years and conversion efficiencies of 10% in two to three years, ultimately aiming at industry-relevant solutions.”

http://www.plextronics.com http://www.solvay.com http://www.imec.be

Cover-Image: Organic solar cell modules, composed of 10 devices in monolithic series connection. The solar cells are spincoated and processed on a glass substrate. Possible applications are PV-integrated window panes. © imec

Right: Organic solar cells with spraycoated active layer (P3HT:PCBM), on glass substrate. Imec optimizes the spraycoating technique to make it an industry-viable cost- effective alternative for spincoating. © imec

11-08 :: August 2011