Aggregation in a high-mobility n-type low-bandgap copolymer with implications on semicrystalline morphology

Robert Steyrleuthner, Marcel Schubert, Ian Howard, Bastian Klaumünzer, Kristian Schilling, Zhihua Chen, Peter Saalfrank, Frederic Laquai, Antonio Facchetti, Dieter Neher*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

274 Scopus citations

Abstract

We explore the photophysics of P(NDI2OD-T2), a high-mobility and air-stable n-type donor/acceptor polymer. Detailed steady-state UV-vis and photoluminescence (PL) measurements on solutions of P(NDI2OD-T2) reveal distinct signatures of aggregation. By performing quantum chemical calculations, we can assign these spectral features to unaggregated and stacked polymer chains. NMR measurements independently confirm the aggregation phenomena of P(NDI2OD-T2) in solution. The detailed analysis of the optical spectra shows that aggregation is a two-step process with different types of aggregates, which we confirm by time-dependent PL measurements. Analytical ultracentrifugation measurements suggest that aggregation takes place within the single polymer chain upon coiling. By transferring these results to thin P(NDI2OD-T2) films, we can conclude that film formation is mainly governed by the chain collapse, leading in general to a high aggregate content of ∼45%. This process also inhibits the formation of amorphous and disordered P(NDI2OD-T2) films.

Original languageEnglish (US)
Pages (from-to)18303-18317
Number of pages15
JournalJournal of the American Chemical Society
Volume134
Issue number44
DOIs
StatePublished - Nov 7 2012

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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