Abstract
The soft character of organic materials leads to strong coupling between molecular, nuclear and electronic dynamics. This coupling opens the way to influence charge transport in organic electronic devices by exciting molecular vibrational motions. However, despite encouraging theoretical predictions, experimental realization of such approach has remained elusive. Here we demonstrate experimentally that photoconductivity in a model organic optoelectronic device can be modulated 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 1,500-1,700 cm-1 region leads to photocurrent enhancement. Excited vibrations affect predominantly trapped carriers. 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. This presents a new tool for studying electron-phonon coupling and charge dynamics in (bio)molecular materials.
| Original language | English |
|---|---|
| Article number | 7880 |
| Journal | Nature Communications |
| Volume | 6 |
| DOIs | |
| State | Published - 6 Aug 2015 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2015 Macmillan Publishers Limited. All rights reserved.
Funding
We thank Richard Friend, Ayelet Vilan and Dassia Egorova for useful discussions, and Johannes Zimmermann and Tobias Glaser for the angle-dependent infrared spectra. This work was supported by the Netherlands Organization for Scientific Research (NWO) through the ‘Stichting voor Fundamenteel Onderzoek der Materie’ (FOM) research programme. A.A.B. also acknowledges a VENI grant from the NWO. A.A.B. is currently a Royal Society University Research Fellow. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 639750). R.L. acknowledges a Marie Curie IE Fellowship from the EU, held at the Weizmann Institute (FP7-PEOPLE-2011-IEF no. 29866). X.Y. thanks the Council for Higher Education (Israel) for a PBC programme postdoctoral research fellowship. V.C. thanks support from the Office of Naval Research and MURI Center on Advanced Molecular Photovoltaics, award No. N00014-14-1-0580. J.L.B. acknowledges support by competitive research funding from King Abdullah University of Science and Technology (KAUST) and by ONR Global, Grant N62909-15-1-2003. D.C. thanks the Israel Science Foundation Centre of Excellence program, the Grand Centre for Sensors and Security and the Schmidt Minerva Centre for Supramolecular Architecture for partial support. D.C. holds the Sylvia and Rowland Schaefer Chair in Energy Research.
| Funders | Funder number |
|---|---|
| Grand Centre for Sensors and Security | |
| Israel Science Foundation Centre of Excellence program | |
| MURI Center on Advanced Molecular Photovoltaics | N00014-14-1-0580 |
| Schmidt Minerva Centre for Supramolecular Architecture | |
| Office of Naval Research | N62909-15-1-2003 |
| Horizon 2020 Framework Programme | 639750 |
| FP7 People: Marie-Curie Actions | 29866 |
| European Commission | |
| European Commission | |
| Stichting voor Fundamenteel Onderzoek der Materie | |
| Nederlandse Organisatie voor Wetenschappelijk Onderzoek | |
| King Abdullah University of Science and Technology | |
| Council for Higher Education |