Dresden 2014 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Poster Session 1 (joint session with BP)

CPP 19.38: Poster

Tuesday, April 1, 2014, 09:30–13:00, P1

Surface morphology of P3HT, PCBM and blends of both — •Martin Dehnert¹, Mario Zerson¹, Alessandro Sepe², Sven Hüttner², Zhuxia Rong², Ullrich Steiner², and Robert Magerle² — ¹Chemische Physik, Fakultät für Naturwissenschaften, Technische Universität Chemnitz, Germany — ²Cavendish Laboratory, JJ Thomson Avenue, Cambridge, U.K

We investigate the surface morphology and the nanomechanical properties of thin films of pure regioregular poly(3-hexylthiophene) (P3HT), [6,6]-phenyl C61-butyric acid methyl ester (PCBM) and blends of both using atomic force microscopy (AFM) operated in multi-set point intermittent contact (MUSIC) mode. This allows for depth-resolved mapping of the mechanical properties of the top surface layer of the specimen. AFM images of pure P3HT and PCBM before and after annealing at 175°C show the morphology at the film surface. Both materials form a nanocrystalline texture with 10 * 30 nm large domains, but with different nanomechanical properties and different surface roughness. The P3HT surface is covered with a 3-nm-thick, compliant surface layer whereas the PCBM surface is stiff and shows less tip indentation. The small needlelike crystals of PCBM are only visible in the attractive regime of the tip-sample-interaction. Thin films of blends of P3HT:PCBM were treated with 1,8-diiodooctane, a selective solvent for PCBM. This allows us to identify the contribution of PCBM to the microstructure at the blend-air-surface.