Photoinduced reversible switching of charge carrier mobility in conjugated polymers

¹ Brno University of Technology, Faculty of Chemistry, Purkynova 118, 612 00 Brno, Czech Republic
² Institute of Macromolecular Chemistry, AS CR, v.v.i., Prague, Czech Republic

Corresponding author: xcnavratil@fch.vutbr.cz

Received: 29 August 2008
Revised: 3 April 2009
Accepted: 21 April 2009
Published online: 26 June 2009

Abstract

Photoinduced reversible switching of charge carrier mobility in conjugated polymers was studied by theoretical and experimental methods. The quantum chemical calculations showed that the presence of dipolar species in the vicinity of a polymer chain modifies the on-chain site energies and consequently increases the width of the distribution of hopping transport states. The influence of photoswitchable charge carrier traps on charge transport was evaluated by current-voltage measurement and by impedance spectroscopy method. It was found that deep traps switchable by photochromic reaction may significantly control the transport of charge carriers, which is exemplified as a significant decrease of the current and increase of parallel resistance measured by impedance spectroscopy.