Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany, and Fraunhofer-Institut für Photonische Mikrosysteme, 01109 Dresden
Due to their advantageous properties such as low materials usage, flexibility, and transparency, organic solar cells have been recently investigated intensively. Recently, device efficiencies have grown quickly and first results above 10% have been reported.
However, to be serious contenders for power generation applications, organic solar cells still need a significant improvement in terms of efficiency and lifetime. In this talk, we discuss our recent work on the investigation of some of the relevant processes which need to be understood to reach these goals. For instance, organic solar cells often suffer from distorted IV-curves due to charge carrier mobility imbalances and energy barriers at interfaces. Furthermore, the efficient charge carrier generation requires a careful adjustment of deposition conditions of the photoactive layers in form of a bulk heterojunction and corresponding optical spacers. Optimized tandem devices realized in collaboration with our partner Heliatek have achieved efficiencies beyond approaching 10% on application-relevant device areas. Finally, methods for the efficient deposition of such organic solar cells will be discussed.