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