Regensburg 2004 – scientific programme

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SYOH: Organic and Hybrid Systems for Future Electronics

SYOH 5: Poster

SYOH 5.42: Poster

Thursday, March 11, 2004, 18:00–21:00, B

High efficiency vacuum deposited solar cells using single or multiple p-i-n architecture. — •Steffen Grundmann, Jens Drechsel, Bert Männig, Wenge Guo, Karl Leo, and Martin Pfeiffer — Insitut für Angewandte Photophysik, TU Dresden, D-01062 Dresden, Germany

We introduce a p-i-n type heterojunction architecture for organic solar cells where the active region (i) is sandwiched between two doped wide-gap layers (p and n). The photoactive layer is formed by a mixture of zinc phthalocyanine (ZnPc) and the fullerene C60. In the blend layer, the ZnPc is found in an amorphous morphology while C60 forms nanocrystallites of less than 10nm size. The solar cells exhibit an external quantum efficiency of around 40% between 630nm and 700nm wavelength. With the help of an optical multilayer model, we optimize the optical properties of the solar cells by placing the active region at the maximum of the optical field distribution. The results of the model are largely confirmed by the experimental findings. For an optically optimized device, we find an internal quantum efficiency of around 85% at short-circuit conditions. Adding 10nm thick layer of the red material PTCBI to the active region, a power conversion efficiency of 2% is obtained. Such optically thin cells with high internal quantum efficiency are an important step towards high efficiency tandem cells. First tandem cells, which are not yet optimized, already show 2.4% power conversion efficiency. Moreover, we present first promising results on device lifetime under simulated AM 1.5 conditions.