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HL: Fachverband Halbleiterphysik

HL 21: Organic electronics and photovoltaics II (organized by CPP)

HL 21.5: Vortrag

Montag, 31. März 2014, 16:30–16:45, ZEU 222

Conjugated oligomers near surfaces with different physical and chemical nature: MD simulation of adsorption layers — •Olga Guskova¹ and Jens-Uwe Sommer^{1, 2} — ¹Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, D-01069 Dresden — ²Techische Universität Dresden, Institut für Theoretische Physik, Zellescher Weg 17, D-01062 Dresden

Atomistic molecular dynamics simulations are used to explore some general principles of 2D supramolecular organization of conjugated oligomers on adsorbing substrates. Two systems are studied: (i) terminally substituted dicyanovinyl quaterthiophenes, prototypic absorbers for small molecule organic solar cells on a silica surface [1] and (ii) 2,5-dialkoxy-phenylene-thienylene-based oligomers on epitaxial monolayer graphene [2]. We demonstrate that the driving force of molecular orientation on substrate is embodied by the chemical nature of the surface and the character and position of functional groups the conjugated molecule bearing, i.e. the underlying balance of forces defines the spatial orientation - standing upright or lying-down molecules on substrates. This force balance clearly allows isolated molecules to explore flat, bent or twisted molecular conformations and to exploit force anisotropies to maximize their interactions when crystals are growing. [1] O.A. Guskova et al. // J. Phys. Chem. C 2013. V. 117. P. 17285. [2] R. Shokri et al. // J. Am. Chem. Soc. 2013. V. 135. P. 5693.