Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 13: Poster Session I
HL 13.59: Poster
Monday, March 12, 2018, 17:30–19:30, Poster B
Formation Dynamics of Charge-Transfer States at the Pentacene/Perfluoropentacene Interface — •Melanie Fey1, Robin Carl Döring1, Andre Rinn2, Tobias Breuer2, Gregor Witte2, and Sangam Chatterjee1 — 1Institute of Experimental Physics I, Justus-Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Gießen, Germany — 2Faculty of Physics and Materials Science Center, Philipps-Universität Marburg, Renthof 5, D-35032 Marburg, Germany
Model crystalline molecular donor-acceptor heterostructures allow systematic investigations of the charge-carrier dynamics at the internal interfaces. Here, we investigate the charge-transfer (CT) exciton dynamics in different intermixed and layered heterostructures of pentacene (PEN) and perfluoropentacene (PFP). We study the formation of interfacial CT states by comparing low-temperature photoluminescence excitation spectroscopy and linear absorption spectroscopy measurements. We find that an excitation at the lowest-energy bright exciton resonance of PEN directly leads to emission at the CT exciton energies while no such contribution is observed for the lowest bright exciton energy of PFP. The corresponding linear absorption spectra, however, reveal significant oscillator strength for both resonances. Our results thus indicate firstly, that PEN is the main contributor to the formation of CT excitons in PEN-PFP heterosystems and, secondly reveals limitations of a description of CT exciton states relying on the robustness of the frontier molecular orbitals at the hetero interface.