Regensburg 2007 – scientific programme

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DS: Fachverband Dünne Schichten

DS 6: Organic Photovoltaics (SYOE 2)

DS 6.7: Talk

Monday, March 26, 2007, 17:30–17:45, H32

Inkjet Printing of Polymer based Solar Cells — •Claudia Klepek, Pavel Schilinsky, Stelios Choulis, and Christoph Brabec — Konarka Technologies GmbH, Nürnberg, Germany

A variety of approaches have been used to deposit organic semiconductors based on the nature of those materials. The commonly applied technique is the solution-processed deposition. Due to the low-cost roll-to-roll production, the printing technologies are attracting more and more attention. Inkjet printing is very promising because the polymer devices can be fabricated very easily in terms of no-mask patterning. We report an organic photovoltaic device depositing the photoactive layer, comprising P3HT blended with the fullerene PC61BM in a solvent mixture, by a piezoelectric inkjet printing system. We compared two P3HTs differing in the molecular weight distribution (MW). A lower MW of the P3HT has been suited for inkjet printing since the latency time until gelification of the solution occurs is longer. The device performance and limitation of an IJ printed cell were well-investigated and remarkable losses in the short circuit current have been assessed. Among other things, losses in the short circuit current can be attributed to the low deposition temperature for comparatively high-boiling solvents. The drying rate affects the device performance significantly. The morphology and surface roughness of IJ printed films have been examined by atomic force microscopy. The roughness has been controlled by a careful selection of organic solvents. Due to an adapted solvent mixture the short circuit current and the efficiency have been improved.