Influence of synthetic pathway, molecular weight and side chains on properties of indacenodithiophene-benzothiadiazole copolymers made by direct arylation polycondensation
Journal article, 2021

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 similar to 10(-2) cm(2) 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 similar to 10(-1) cm(2) V-1 s(-1).

Author

Desiree Adamczak

Technische Universität Chemnitz

Andrea Perinot

Istituto Italiano di Tecnologia

Hartmut Komber

Leibniz Institute for Polymer Research

Anna Illy

Technische Universität Chemnitz

Sandra Hultmark

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Christian Müller Group

Bianca Passarella

Polytechnic University of Milan

Istituto Italiano di Tecnologia

Wen Liang Tan

Monash University

Sebastian Hutsch

Technical University of Munich

Technische Universität Dresden

David Becker-Koch

Technische Universität Dresden

Charlotte Rapley

Imperial College London

Alberto D. Scaccabarozzi

Istituto Italiano di Tecnologia

Martin Heeney

Imperial College London

Yana Vaynzof

Technische Universität Dresden

Frank Ortmann

Technical University of Munich

Technische Universität Dresden

Christopher R. McNeill

Monash University

Christian Müller

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Christian Müller Group

Mario Caironi

Istituto Italiano di Tecnologia

Michael Sommer

Technische Universität Chemnitz

Journal of Materials Chemistry C

2050-7534 (ISSN)

Vol. 9 13 4597-4606

Subject Categories

Polymer Chemistry

Theoretical Chemistry

Organic Chemistry

DOI

10.1039/d1tc00043h

More information

Latest update

4/28/2021