Regensburg 2010 – scientific programme

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DS: Fachverband Dünne Schichten

DS 6: [HL] Organic Semiconductors: Solar Cells (Joint Session DS/CPP/HL/O)

DS 6.7: Talk

Monday, March 22, 2010, 17:30–17:45, H15

Charge Carrier Generation Yield in Organic Solar Cells using a C80 Derivative as Acceptor — •Moritz Liedtke^1,2, Andreas Sperlich², Hannes Kraus², Andreas Baumann², Carsten Deibel², Vladimir Dyakonov^1,2, and Claudia Cardona³ — ¹Centre for Applied Energy Research (ZAE Bayern e. V.), Am Hubland, D-97074 Würzburg, Germany — ²Experimental Physics VI, Physical Institute, Julius-Maximilians-University of Würzburg, Am Hubland, D-97074 Würzburg — ³Luna Innovations Incorporated, 521 Bridge Street, Danville, VA 24541 (USA)

Organic solar cells (OSC) with C₇₀ and C₈₀ fullerenes show a higher open circuit voltage (Voc) than the standard [6,6]-phenyl-C[61]-butyric acid methyl ester (PCBM):poly-3-hexylthiophene (P3HT) bulkheterojunction cells. Devices containing the trimetallic nitride endohedral fullerene Lu₃:N@C₈₀ showed a Voc of 910mV compared to 600mV with C₆₀-PCBM. Still the overall efficiency of these cells remain below the performance of our C₆₀-PCBM:P3HT reference cells. We address the origin of the lower efficiency by means of optical, magnetic and current measurement techniques. In samples containing Lu₃:N@C₈₀ we found photoluminescence quenching 3.2 times weaker, triplet yield higher and short-cut current about 2mA/cm² lower than in cells with C₆₀-PCBM as acceptor. We conclude that less efficient charge carrier generation in the Lu₃:N@C₈₀:P3HT bulkheterojunction system is the reason for the lower photocurrent.