Dresden 2026 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 53: Organic Semiconductors: Carrier Dynamics

HL 53.6: Vortrag

Freitag, 13. März 2026, 11:00–11:15, POT/0051

Multiscale Modelling of the Density of States in PEDOT:Tosylate Films — •Melissa Kim Meinel and Igor Zozoulenko — Laboratory of Organic Electronics, Linköping University, Norrköping, Sweden

A key descriptor of the electronic structure is the density of states (DOS), which directly affects properties such as charge mobility, intrinsic capacitance, and optical absorption. Structural disorder and the local electrostatic environment strongly influence the DOS but are rarely captured in full detail in computational studies that often rely on small model systems or simplified methods. We present a multiscale modelling approach for computing the DOS of realistic PEDOT:Tosylate films. Molecular dynamics simulations generate film structures that capture the complex packing and disorder of PEDOT chains and counterions. These configurations are analysed within a quantum mechanical/molecular mechanical (QM/MM) framework, where molecular mechanics accounts for large-scale heterogeneity while quantum calculations resolve local electronic states under explicit electrostatic embedding of the environment. Steric effects are treated at the MM level, while the QM region can be limited to a single chain. Accurate results require optimally tuned range-separated hybrid functionals, geometry optimisation of the QM chain, and iterative adaptation of charge distributions to capture realistic environmental effects. This framework enables quantitatively realistic, morphology-sensitive predictions of the electronic structure and has been applied to systems at different oxidation levels.

Keywords: Multiscale Modelling; Density Functional Theory; Moleular Dynamics; Electronic Structure; Structure-property relationships