Polymer Science Faculty Research

Title

Regioregular poly(3-alkanoylthiophene): Synthesis and electrochemical, photophysical, charge transport, and photovoltaic properties

Document Type

Article

Publication Date

11-1-2010

Abstract

Head-to-tail regioregular poly(3-heptanoylthiophene) (PHOT) was synthesized by Ni-catalyzed polycondensation of the 2,2-dimethyl-1,3-propanediol-protected Grignard monomer followed by deprotection. Cyclic voltammetric (CV) study demonstrates that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of PHOT are 0.5 eV lower in energy than those of the head-to-tail poly(3-hexylthiophene) (HT-P3HT). Their optical band gaps are essentially the same. Incomplete photoluminescence (PL) quenching was observed in thin films of the 1:1 blend of PHOT and HT-P3HT. PHOT displayed a glass transition at ∼269 °C and decomposed at ∼300 °C according to differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Wide-angle X-ray diffraction (WAXD) study showed that PHOT exists in a not highly ordered state in solid films especially in the π-stacking direction. Only p-channel activity was observed in field-effect transistors (FETs) for PHOT. The hole mobility was on the order of 10−4 cm2 V−1 s−1. Photovoltaic devices with an active layer of 1:1 blend of PHOT and PC71BM had a power conversion efficiency (PCE) of ∼0.5%. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Publication Title

Journal of Polymer Science Part A: Polymer Chemistry

Volume

48

Issue

21

First Page

4681

Last Page

4690