Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 35: Organic-inorganic hybrid systems and organic films IV
O 35.2: Talk
Tuesday, March 13, 2018, 14:15–14:30, MA 042
Theory of the geometry-dependent excitation transfer across a semiconductor/molecule interface — •Judith Specht1, Björn Bieniek2, Patrick Rinke2,3, Andreas Knorr1, and Marten Richter1 — 1Technische Universität Berlin, Berlin, Germany — 2Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany — 3Aalto University, Aalto, Finland
Förster-type non-radiative coupling can transfer electronic excitations from inorganic semiconductor substrates to Frenkel excitons in organic molecular films. We analyze the excitation transfer efficiency as a function of the molecular geometry and other parameters such as charge carrier densities and temperatures.
Using a density-matrix equation technique, we study the case of creating excitons in an optically active layer of ladder-type quarterphenyl (L4P) molecules by strong electrical pumping of the electron-hole continuum in a ZnO quantum well substrate. Ab initio calculations provide the microscopic input parameters for our density-matrix equation technique [1,2]. Our findings reveal that the coupling efficiency strongly depends on multiple, but tunable parameters such as resonance energy detuning, molecular coverage, charge carrier occupation in the semiconductor substrate, distance between the constituents, and spatial orientation of the flat-lying molecules on the substrate. Our parameter study enables us to explore the operating regimes for optimized device performance.
[1] Verdenhalven et al., Phys. Rev. B 89, 235314 (2014).
[2] Specht et al., arXiv:1711.08955.