Christoph Brabec

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Experimental LEDs were fabricated in the following manner. Indium tin oxide (ITO) sub-strates were cleaned by ultrasonication in detergent, acetone, and isopropanol. Cleaning was followed by a 5 min oxygen plasma etch at 100 W at 300 Torr of oxygen. After etching, poly(3,4-ethylenedioxythiophene) (PEDOT, Baytron P8000 from Bayer) was spin-cast at 3800 RPM(More)
Organic photovoltaics in a flexible wire format has potential advantages that are described in this paper. A wire format requires long-distance transport of current that can be achieved only with conventional metals, thus eliminating the use of transparent oxide semiconductors. A phase-separated, photovoltaic layer, comprising a conducting polymer and a(More)
Solution-processed inverted bulk heterojunction (BHJ) solar cells have gained much more attention during the last decade, because of their significantly better environmental stability compared to the normal architecture BHJ solar cells. Transparent metal oxides (MeO x) play an important role as the dominant class for solution-processed interface materials(More)
The new lifetime record approximately doubled the previous lifetime record that was observed in P3HT:PC 60 BM OPV devices. [ 6 ] Degradation in encapsulated polymer solar cells cannot be attributed to any one mechanism; [ 8–12 ] but, the different mechanisms of degradation in polymer solar cells can be classifi ed into three general categories. The fi rst(More)
Solution-processed organic photovoltaics (OPV) offer the attractive prospect of low-cost, light-weight and environmentally benign solar energy production. The highest efficiency OPV at present use low-bandgap donor polymers, many of which suffer from problems with stability and synthetic scalability. They also rely on fullerene-based acceptors, which(More)
The multi-junction concept is the most relevant approach to overcome the Shockley-Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently(More)
In order to commercialize polymer solar cells, the fast initial performance losses present in many high efficiency materials will have to be managed. This burn-in degradation is caused by light-induced traps and its characteristics depend on which polymer is used. We show that the light-induced traps are in the bulk of the active layer and we find a direct(More)
High efficiency polymer:fullerene photovoltaic device layers self-assemble with hierarchical features from ångströms to 100's of nanometers. The feature size, shape, composition, orientation, and order all contribute to device efficiency and are simultaneously difficult to study due to poor contrast between carbon based materials. This study seeks to(More)