Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 10: Organic Electronics and Photovoltaics (organized by DS)
TT 10.6: Talk
Monday, March 16, 2015, 10:45–11:00, H 2032
Mode-selective vibrational manipulation of charge transport in π-conjugated molecular materials — •Robert Lovrincic1,2, Artem A. Bakulin3,4, Yu Xi1, Oleg Selig3, Huib J. Bakker3, Yves L. A. Rezus3, Pabitra K. Nayak1, Alexandr Fonari5, Veaceslav Coropceanu5, Jean-Luc Bredas5,6, 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.