Engineering the self-assembly of diketopyrrolopyrrole-based molecular semiconductors via an aliphatic linker strategy

Xavier A. Jeanbourqui, Aiman Rahmanudin, Andrea Gasperini, Emilie Ripaud, Xiaoyun Yu, Melissa Johnson, Nestor Guijarro, Kevin Sivula

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The solid-state self-assembly of molecular semiconductors is a key aspect for controlling the optoelectronic properties of organic electronic materials. Herein, we investigate the use of a flexible linker strategy to control the self-assembly of a solution-processable diketopyrrolopyrrole semiconductor coded as DPP(TBFu)2. Two distinct dimers—prepared with varied linker position relative to the orientation of the conjugated core—reveal the effect of connectivity on the solid-state self-assembly and optoelectronic properties—favoring either H- or J-type aggregation. The dimer with a “vertical” linker orientation exhibits a poor crystallinity in neat films, but improves hole mobility in OFETs 10-fold, reaching 3.0 × 10−3 cm2 V−1 s−1 when used as an additive with DPP(TBFu)2. Distinctively, the dimer with a “horizontal” linking orientation does not enhance charge carrier transport, but is found to affect the thermal stability of donor : acceptor blends in OPVs with PCBM. Devices retain 90% of their initial conversion efficiency after 5 hours of thermal stress, compared to only 45% for control devices. Thermodynamic and kinetic rationales further suggest that this flexible linker strategy represents a powerful tool to control supramolecular assembly in molecular semiconductors without altering the nature of the core conjugated segment.
    Original languageEnglish
    Pages (from-to)10526-10536
    Number of pages11
    JournalJournal of Materials Chemistry A
    Volume5
    Issue number21
    Early online date16 May 2017
    DOIs
    Publication statusPublished - 7 Jun 2017

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