Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 2: Focus Session: Structural Ordering and Electronic Transport I (jointly with CPP)

HL 2.5: Vortrag

Montag, 26. März 2012, 10:45–11:00, ER 270

Developing hybrid simulation schemes for mesoscale modeling of morphologies in organic semiconductors — •Kostas Daoulas^1,2, Victor Ruehle^1,3, and Kurt Kremer¹ — ¹Max Planck Institute for Polymer Research, Mainz, Germany — ²Innovation Lab GmbH, Heidelberg, Germany — ³Department of Chemistry, University of Cambridge, United Kingdom

Hybrid simulations use a particle-based description while defining some interactions via collective variables. These degrees of freedom are soft; thus significant speedups of simulations are possible and large systems can be addressed. However, this softness of interactions poses challenges in modeling organic semiconductors where the local liquid structuring (e.g. pi-pi stacking) affects the mesoscale properties. As a first step in developing hybrid approaches incorporating this interplay, we consider here Monte Carlo simulations of homopolymer melts with nematic liquid-crystalline (LC) behavior. The polymers are described as discrete worm-like chains, a simple density functional controls the compressibility, and a functional of the local segmental orientation tensor captures the LC ordering. We illustrate that the method can address large systems parameterized according to volumetric and conformational properties representative of semiconductor materials by establishing a rough correspondence with regiorandom P3HT melts. Chain conformations and the effect of the molecular weight on the isotropic-nematic transition are studied. The formation of the nematic phase is addressed within the Rouse-like dynamics realized by the current model. We discuss directions of further methodological developments.