Europhys. Lett.
Volume 65, Number 3, February 2004
Page(s) 386 - 392
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 January 2004
Europhys. Lett., 65 (3) , pp. 386-392 (2004)
DOI: 10.1209/epl/i2003-10102-7

Photocurrent in conjugated polymers

B. Horovitz and E. Pazy

Department of Physics and Ilze Katz center for nanotechnology Ben-Gurion University of the Negev - Beer-Sheva 84105, Israel

(Received 2 June 2003; accepted in final form 28 November 2003)

Non-linear photocurrent carriers in conjugated polymers, such as polarons, bipolarons and solitons, are considered at low photon energies where a tunnelling process is necessary. We show that polarons dominate the photocurrent I due to a novel electric-field-assisted tunnelling route for which $\ln I\sim
-E^{-2/3}$ . For near-degenerate polymers with an electric field E which exceeds the confinement parameter and frequencies near twice the soliton energy, soliton formation is favored. Photocurrent data can then be used to identify the remarkable soliton conduction.

71.38.-k - Polarons and electron-phonon interactions.
72.15.Nj - Collective modes (e.g., in one-dimensional conductors).
71.38.Mx - Bipolarons.

© EDP Sciences 2004