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
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
Mario Caironi
Istituto Italiano di Tecnologia
Michael Sommer
Technische Universität Chemnitz
Journal of Materials Chemistry C
20507534 (ISSN) 20507526 (eISSN)
Vol. 9 13 4597-4606Subject Categories
Polymer Chemistry
Theoretical Chemistry
Organic Chemistry
DOI
10.1039/d1tc00043h