Issue 13, 2021

Influence of synthetic pathway, molecular weight and side chains on properties of indacenodithiophene-benzothiadiazole copolymers made by direct arylation polycondensation

Abstract

Atom-economic protocols for the synthesis of poly(indacenodithiophene-alt-benzothiadiazole) (PIDTBT) are presented in which all C–C coupling steps are achieved by direct arylation. Using two different synthetic pathways, PIDTBT copolymers with different side chains (hexylphenyl, octylphenyl, dodecyl, methyl/2-octyldodecylphenyl, 2-octyldodecylphenyl/2-octyldodecylphenyl) and molecular weight (MW) are prepared. Route A makes use of direct arylation polycondensation (DAP) of indacenodithiophene (IDT) and 4,7-dibromo-2,1,3-benzothiadiazole (BTBr2) leading to PIDTBT in high yields, with adjustable MW and without indications for structural defects. Route B starts from a polyketone precursor also prepared by DAP following cyclization. While route B allows introduction of asymmetric side chains at the IDT unit, polymer analogous cyclization gives rise to defect formation. The absorption coefficient of PIDTBT with alkylphenyl side chains made by route A increases with MW. Field-effect hole mobilities around ∼10−2 cm2 V−1 s−1 are molecular weight-independent, which is ascribed to a largely amorphous thin film morphology. PIDTBT with linear dodecyl side (C12) chains exhibits a bathochromic shift (20 nm), in agreement with theory, and more pronounced vibronic contributions to absorption spectra. In comparison to alkylphenyl side chains, C12 side chains allow for increased order in thin films, a weak melting endotherm and lower energetic disorder, which altogether explain substantially higher field-effect hole mobilities of ∼ 10−1 cm2 V−1 s−1.

Graphical abstract: Influence of synthetic pathway, molecular weight and side chains on properties of indacenodithiophene-benzothiadiazole copolymers made by direct arylation polycondensation

Supplementary files

Article information

Article type
Paper
Submitted
04 Jan 2021
Accepted
10 Mar 2021
First published
10 Mar 2021

J. Mater. Chem. C, 2021,9, 4597-4606

Influence of synthetic pathway, molecular weight and side chains on properties of indacenodithiophene-benzothiadiazole copolymers made by direct arylation polycondensation

D. Adamczak, A. Perinot, H. Komber, A. Illy, S. Hultmark, B. Passarella, W. L. Tan, S. Hutsch, D. Becker-Koch, C. Rapley, A. D. Scaccabarozzi, M. Heeney, Y. Vaynzof, F. Ortmann, C. R. McNeill, C. Müller, M. Caironi and M. Sommer, J. Mater. Chem. C, 2021, 9, 4597 DOI: 10.1039/D1TC00043H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements