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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 3: Organic Electronics and Photovoltaics - Layer Morphology and Molecular Aggregation

CPP 3.6: Talk

Monday, March 12, 2018, 11:15–11:30, C 243

Studying lamellar-like morphologies of conjugated polymers through a new symmetry-inspired model — •Cristina Greco, Kurt Kremer, and Kostas Daoulas — Max Planck Institute for Polymer Research, Mainz, Germany

In conjugated polymers, charge transport properties are known to be strongly affected by morphology. An interesting recent observation is that, to achieve high mobilities, perfect lamellar order is not necessary [1]. Here we present a simple model that enables the study of morphologies with partial lamellar order, at device-relevant length scales. Nonbonded interactions responsible for coplanarity in chain orientation and for stacking are described by anisotropic soft potentials constructed on the basis of symmetry considerations. Using polyalkylthiophenes as a test system, we perform Monte Carlo simulations of chains of various lengths. Lamellar-like morphologies are obtained, either as mono- or polydomains. The type of lamellar order is identified by computing 2D scattering patterns, which can be compared with experimental GIWAXS data. From this analysis, we conclude that our morphologies correspond to a smectic mesophase, which was also reported in experiments [2]. We analyze the organization of chains inside the lamellae and identify in a simple way connectivity pathways between the lamellae. In perspective, atomistic detail can be reintroduced via backmapping, allowing for prediction of charge transport [3]. [1] R. Noriega et al. Nat. Mater. 2013, 12, 1038. [2] Z. Wu et al. Macromolecules 2010, 43, 4646. [3] P. Gemünden et al. Macromol. Rapid Commun. 2015, 36, 1047.