title: Pd-catalysed direct arylation polymerisation for synthesis of low-bandgap conjugated polymers and photovoltaic performance.
abstract: 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. The polymers are used to fabricate organic photovoltaic devices and the best performing PCPDTBT device exhibits a moderate improvement over devices fabricated using the related polymer via Suzuki coupling. Similar polymerisation conditions have also been applied for other monomer units.
authors.affiliation: Frontier Research Center on Fundamental and Applied Sciences of Matters, Department of Chemical Engineering, National Tsing-Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan.
authors.forename: Shu-Wei
authors.initials: SW
authors.lastname: Chang
authors.forename: Huw
authors.initials: H
authors.lastname: Waters
authors.forename: Jeff
authors.initials: J
authors.lastname: Kettle
authors.forename: Zi-Rui
authors.initials: ZR
authors.lastname: Kuo
authors.forename: Chun-Han
authors.initials: CH
authors.lastname: Li
authors.forename: Chin-Yang
authors.initials: CY
authors.lastname: Yu
authors.forename: Masaki
authors.initials: M
authors.lastname: Horie
mesh_terms: D002384:Catalysis; D008970:Molecular Weight; D010165:Palladium / Q000737:chemistry*; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D011760:Pyrrolidinones / Q000737:chemistry; D012993:Solar Energy; D013830:Thiadiazoles / Q000737:chemistry
chemical_list: D011108:Polymers; D011760:Pyrrolidinones; D013830:Thiadiazoles; C555055:poly(2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta(2,1-b-3,4-b0)dithiophene))-alt-4,7-(2,1,3-benzothiadiazole); D010165:Palladium; C038678:N-methylpyrrolidone