Dresden 2009 – scientific programme

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SYOP: Symposium Organic Photovoltaics: From Single Molecules to Devices

SYOP 4: Organic Photovoltaics: from Single Molecules to Devices

SYOP 4.67: Poster

Thursday, March 26, 2009, 16:30–19:00, P1A

Improved morphology of C60:ZnPc blend solar cells by using heated substrates — •Steffen Pfuetzner, Moritz Riede, and Karl Leo — Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany, http://www.iapp.de

To reach higher efficiencies in organic solar cells, ideally the open circuit voltage (Voc), fill factor (FF), and the short current density (jsc) has to be further improved. It is well known from polymer based solar cells that the morphology of the photoactive layers can have a significant influence on the jsc and FF. However, only few such studies are available for small molecule based solar cells. This work investigates the effects of substrate temperature on the morphology of the photoactive layer during vacuum deposition of the organic absorber materials. AFM, SEM and TEM measurements were done to characterize the morphological changes. Complete solar cells with a 150nm thick blend layer of C60 and ZnPc were fabricated at different substrate temperatures to study the morphology. It was shown that jsc reaches a maximum at 110°C due to the balance of improved transport paths and charge carrier generation. Further optimization of the thin film optic led to a 60 nm blend solar cell which was made at 110°C. This device shows a high FF of 56% and a p.c. efficiency of 2.6%.