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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Poster: Organic Semiconductors
CPP 8.39: Poster
Monday, March 14, 2011, 17:30–19:30, P2
Deep Insight into the Spectroscopic Properties of a High Mobility n-type conjugated Polymer with Implications on Morphology and Charge Transport — •Robert Steyrleuthner1, Marcel Schubert1, Zhihua Chen2, Antonio Facchetti2, and Dieter Neher1 — 1Universität Potsdam, Germany — 2Polyera Corporation, USA
Electrical properties of conjugated polymers are severely influenced by the morphology of the semiconducting layer. Recently, Facchetti and coworkers reported a novel n-type polymer (Polyera ActivInk N2200) with an exceptionally high electron field-effect-mobility of up to 0.85 cm2/Vs. We could already show that the bulk mobility in this material is indeed high, though electron injection is contact limited for all used low work function cathodes. While it was initially believed that layers from N2200 are amorphous, X-ray studies by Rivnay et al. on N2200 showed an exceptional in-plane order with distinct "pi-stacking" of the naphthalene diimide cores. The purpose of our work was to study the morphology of N2200 layers prepared from different solvents and annealed at different temperatures. Information on the chain packing and layer structure was obtained by performing UV-Vis absorbance, photoluminescence, AFM and SNOM measurements on thin films and solutions. We could identify distinct absorbing species and assign them to intrachain charge-transfer excitons in the amorphous phase and to interchain excitations on aggregated chains. On this basis, conclusions regarding the morphology of the semicrystalline films are drawn and related to bulk charge transport properties.