Pd-catalysed direct arylation polymerisation for synthesis of low-bandgap conjugated polymers and photovoltaic performance.

Low-bandgap conjugated copolymers based on a donor-acceptor structure have been synthesised via palladium-complex catalysed direct arylation polymerisation. Initially, we report the optimisation of the synthesis of poly(cyclopentadithiophene-alt-benzothiadiazole) (PCPDTBT) formed between cyclopentadithiophene and dibromobenzothiadiazole units. The polymerisation condition has been optimised, which affords high-molecular-weight polymers of up to M(n) = 70 k using N-methylpyrrolidone as a solvent.