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Senkovsky, V. ; Sommer, M. ; Tkachov, R. ; Komber, H. ; Huck, W. T. S. ; Kiriy, A.
Convenient route to initiate kumada catalyst-transfer polycondensation using ni(dppe)CI2 and sterically hindered grignard compounds

Conjugated polymers (CPs) attract considerable attention as promising materials for solar cells, field effect transistors, light-emitting diodes, etc.(1) However, the properties of existing CPs that are prepared predominantly by conventional step-growth polycondensations are still far from optimal. For industrial-scale applications, CPs with controllable molecular weight (MW), MW distribution, chain-end functionality, minimum amounts of defects, and as a result, controlled and reproducible optoelectronic properties are required. In addition, new CP architectures are needed that predictably self-assemble into desirable nanomorphologies, thus solving a longstanding problem with improper morphologies of active layers in optoelectronic devices.(1) Nowadays, chain-growth Kumada catalyst transfer polycondensations (KCTP), also referred to as Grignard metathesis polymerization (GRIM),(2) has become a powerful tool for the synthesis of well-defined polymers,(3) all-conjugated block copolymers(4) and polymer brushes.(8-10) However, despite impressive progress, several important challenges still remain. Although a number of model thiophene-based conjugated block copolymers were already synthesized via the sequential polymerization of different monomers,(4a-4e) examples of all-conjugated block copolymers composed of two substantially different blocks remain scarce.(4f-4i) While some effort has been made in synthesizing various types of donor-acceptor block copolymers,(5) all-conjugated block copolymers composed of state-of-the-art electron-donor and electron-acceptor conjugated blocks have not been synthesized to date. Such architectures are potentially promising materials for interface engineering in organic solar cells, especially when considering that power conversion efficiencies of all-polymer blend photovoltaics are currently lagging behind polymer/fullerene derivative-based devices.(6) Difficulties in preparing such block copolymers originate from the synthetic requirements that the two different blocks should be formed with the aid of the same catalyst, under approximately the same polymerization conditions and without a sacrifice in the chain-growth polymerization performance....

Source
Macromolecules 43

Pages
10157-10161

DOI
http://dx.doi.org/10.1021/ma1024889

Published
December 2010
 
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Publications

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Nanostructured Materials