We have developed a new class of heptacyclic ladder-type arenes based on dithienylcarbazole and dithienylfluorene skeleton. The 3-positons of the two outer thiophenes are covalently connected with the 3- and 6-positions of the central fluorene and carbazole core, creating dithienocyclopenta-fluorene (DTCF ), dithienosilolo-carbazole (DTSC ), dithienocyclopenta-carbazole (DTCC ) and dithienopyrrolo-carbazole (DTPC ) structures. The ladder-type monomers were further polymerized with the benzothiadiazole acceptor to furnish alternating donor-acceptor copolymers PD TCF BT ,  PD T C C B T,  PD TCF BT -C8,  PD T C C B T-C8  PDTSCBT , and PDTPCBT .  The devices based on PDTSCBT  and PDTCCBT  exhibited high hole mobility of 0.073 and 0.110 cm2 V-1 s-1, respectively. These mobilities are among the best performance from the amorphous donor-acceptor copolymers. The bulk heterojunction device using Si-bridged PDTSCBT  as the p-type material delivered the best efficiency PCE to 5.2% with a Voc of 0.82 V, a Jsc of 11.1 mA/cm2, a FF of 56.7%.

Synthesis of low-band gap conjugated polymers for photovoltaic applications

243rd National Meeting (2012)

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