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 journalArticle

5 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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