We demonstrate that poly(3,4-dialkylterthiophenes) (P34ATs) have comparable transistor mobilities (0.17 cm2 V-1 s-1) and greater environmental stability (less degradation of on/off ratio) than regioregular poly(3-alkylthiophenes) (P3ATs). Unlike poly(3-hexylthiophene) (P3HT), P34ATs do not show a strong and distinct π-π stacking in X-ray diffraction. This suggests that a strong π-π stacking is not always necessary for high charge-carrier mobility and that other potential polymer packing motifs in addition to the edge-on structure (π-π stacking direction parallel to the substrate) can lead to a high carrier mobility. The high charge-carrier mobilities of the hexyl and octyl-substituted P34AT produce power conversion efficiencies of 4.2% in polymer:fullerene bulk heterojunction photovoltaic devices. An enhanced open-circuit voltage (0.716-0.771 eV) in P34AT solar cells relative to P3HT due to increased ionization potentials was observed. © 2011 American Chemical Society.
|Original language||English (US)|
|Number of pages||4|
|Journal||Journal of the American Chemical Society|
|State||Published - Oct 26 2011|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-C1-015-21
Acknowledgements: This publication was partially based on work supported by the Center for Advanced Molecular Photovoltaics, Award KUS-C1-015-21, made by King Abdullah University of Science and Technology (KAUST). Portions of this research were carried out at the Stanford Synchrotron Radiation Lightsource User Facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.