Berlin 2015 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 1: Organic Electronics and Photovoltaics

DS 1.6: Vortrag

Montag, 16. März 2015, 10:45–11:00, H 2032

Mode-selective vibrational manipulation of charge transport in π-conjugated molecular materials — •Robert Lovrincic^1,2, Artem A. Bakulin^3,4, Yu Xi¹, Oleg Selig³, Huib J. Bakker³, Yves L. A. Rezus³, Pabitra K. Nayak¹, Alexandr Fonari⁵, Veaceslav Coropceanu⁵, Jean-Luc Bredas^5,6, and David Cahen¹ — ¹Department of Materials & Interfaces, Weizmann Institute of Science, Israel — ²IHF, TU Braunschweig & Innovationlab, Germany — ³FOM Institute AMOLF, The Netherlands — ⁴Cavendish Laboratory, University of Cambridge, UK — ⁵School of Chemistry and Biochemistry , Georgia Institute of Technology, USA — ⁶Solar & Photovoltaics Center, King Abdullah University, Saudi Arabia

The soft character of organic materials leads to strong coupling between molecular nuclear and electronic dynamics. This coupling opens the way to control charge transport in organic electronic devices by directing molecular vibrational motions. However, despite encouraging theoretical predictions, experimental realization of such control has remained elusive. Here we demonstrate experimentally that photoconductivity in a model organic optoelectronic device can be controlled by the selective excitation of molecular vibrations. Using an ultrafast infrared laser source to create a coherent superposition of vibrational motions in a pentacene/C60 photoresistor, we observe that excitation of certain modes in the 1500−1700 cm⁻¹ region leads to photocurrent enhancement. The effect depends on the nature of the vibration and its mode-specific character can be well described by the vibrational modulation of intermolecular electronic couplings.