Electron and Hole Contributions to the Terahertz Photoconductivity of a Conjugated Polymer:Fullerene Blend Identified.
Time-resolved terahertz spectroscopy was employed for the investigation of charge-transport dynamics in benzothiadiazolo-dithiophene polyfluorene ([2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]) (APFO-3) polymers with various chain lengths and in its monomer form, all blended with an electron acceptor ([6,6]-phenyl-C61-butyric acid methyl ester, PCBM). Upon photoexcitation, charged polaron pairs are created, negative charges are transferred to fullerenes, while positive polarons remain on polymers/monomers. Vastly different hole mobility in polymer and monomer blends allows us to distinguish the hole and electron contributions to the carrier mobility.
†Division of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden.
Carlito S
CS
Ponseca
‡Institute of Physics, Academy of Sciences of the Czech Republic, 182 21 Prague, Czech Republic.
Hynek
H
Němec
§Scientific Computing Laboratory, Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia.
Nenad
N
Vukmirović
∥Department of Chemical and Biological Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden.
Sandra
S
Fusco
∥Department of Chemical and Biological Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden.
Ergang
E
Wang
∥Department of Chemical and Biological Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden.
Mats R
MR
Andersson
†Division of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden.
Pavel
P
Chabera
†Division of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden.
Arkady
A
Yartsev
†Division of Chemical Physics, Lund University, Box 124, 221 00 Lund, Sweden.
Villy
V
Sundström
organic solar cells; terahertz spectroscopy