Singlet Fission in Core-Shell Micelles of End-Functionalized Polymers

Andrew J. Tilley, Ryan D. Pensack, Emily L. Kynaston, Gregory D. Scholes, Dwight S. Seferos

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Singlet fission is the process in aggregates of molecular semiconductors where the initial product of light absorption (a singlet exciton) is converted into two correlated spin-triplet excitons. While most studies of singlet fission are conducted on assemblies of small molecule singlet fission chromophores, polymer self-assembly has yet to be explored as a means of creating nanostructures conducive for singlet fission. In this work, we use solution self-assembly of mono- and difunctionalized polymers to create core-shell micelles that display efficient singlet fission. The polymers are synthesized by copper(I)-catalyzed "click" chemistry between a 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) alkyne precursor and the corresponding azide-terminated poly(ethylene glycol) (PEG) polymer. Spontaneous solution self-assembly creates starlike and flowerlike core-shell micelles that are characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM) experiments. Ultrafast transient absorption spectroscopy and time-resolved fluorescence experiments evidence nearly equivalent singlet fission dynamics in starlike and flowerlike micelles. Studies on mixed micelles of the Pn-functionalized polymer with a C16-PEG surfactant reveal how triplet pair formation and decay rates vary with micelle composition. The core-shell micelles developed herein demonstrate the potential of polymer self-assembly for creating functional singlet fission nanostructures and provide insight into how secondary components and solubilizing blocks influence singlet fission dynamics and triplet pair losses in self-assembled systems.

Original languageEnglish (US)
Pages (from-to)4409-4421
Number of pages13
JournalChemistry of Materials
Volume30
Issue number13
DOIs
StatePublished - Jul 10 2018

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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