Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 68: Photovoltaics: Organic Semiconductors

HL 68.2: Talk

Wednesday, March 28, 2012, 18:00–18:15, ER 270

Doping induced performance enhancement in low bandgap polymer:fullerene solar cells — •Antonietta De Sio¹, Ali Veysel Tunc¹, Daniel Riedel², Enrico Da Como², Jürgen Parisi¹, and Elizabeth von Hauff³ — ¹Energy and Semiconductor Research Laboratory, Institute of Physics, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany — ²Photonics and Optoelectronics Group, Department of Physics and CeNS, Ludwig-Maximilians-Universität München, 80799 Munich, Germany — ³Institute of Physics, Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany

We investigate the effect of molecular doping in poly[2,6(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b0]-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) and its blend with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Tetrafluoro-tetracyanoquinodimethane (F4-TCNQ) is used to dope PCPDTBT via co-solution at different concentrations. The effect of doping on the transport properties of the neat polymer as well as of the blends is investigated with field effect measurements while photoinduced absorption spectroscopy is employed to get information on the charge separation efficiency. Bulk heterojunction solar cells with molecularly doped active layers were also prepared and characterized. We demonstrate that molecular doping is a simple and effective method to improve the performance in polymer:fullerene solar cells by reducing the recombination and increasing the hole mobility.