Synthesis of Amphiphilic Block Copolymers for OSCs

Amphiphilic di-block copolymers have been suggested as a versatile tool in exploring the role of domain size, domain purity and interfacial energy cascades in bulk heterojunctions. Di-block copolymers can be used to eliminate macro-phase separation while the free energy of the individual blocks can be modified to enable clean phase separation, however current synthetic routes do not normally lead to clean di-block products with contamination with homo-polymers and tri- or higher block by products. Purification can be tedious or impossible. We have previously reported excellent phase separation in P3HT-<i>block</i> F_TEGTBT, while the oxygenated side chains facilitate purification [1]. Here we report the synthesis of asymmetrically functionalised push-pull monomers (AFPPMs) for both p- and n-type organic semiconductors and the pseudo-living polymerisation to give amphiphilic di-block copolymers in a 1-pot synthesis of pBDTBT-<i>b</i>-pN2200 using sequential Stille and Suzuki-Miyaura polymerisation with a Grubbs-3 catalytic system. In this talk I will describe the synthesis of the AFPPMs, material characterisation and OSC device results.<br/>[1] Mitchell, V. D.; Wong, W. W. H.; Thelakkat, M.; Jones, D. J., "The synthesis and purification of amphiphilic conjugated donor-acceptor block copolymers" <i>Polym. J. </i><b>2017,</b> <i>49</i> (1), 155-161. <b>DOI</b>:10.1038/pj.2016.97