Journal of the American Chemical Society
Journal of the American Chemical Society
5 years ago

Tuning Singlet Fission in π-Bridge-π Chromophores

Tuning Singlet Fission in π-Bridge-π Chromophores
Jacob C. Dean, Amir Asadpoordarvish, Lauren M. Yablon, Michael L. Steigerwald, Jonathan Z. Low, Andrew B. Pun, Matthew Y. Sfeir, Bonnie Choi, Samuel N. Sanders, Nandini Ananth, Daniel W. Paley, Murad J. Y. Tayebjee, Timothy J. H. Hele, Elango Kumarasamy, Gregory D. Scholes, Luis M. Campos, Eric G. Fuemmeler, Dane R. McCamey
We have designed a series of pentacene dimers separated by homoconjugated or nonconjugated bridges that exhibit fast and efficient intramolecular singlet exciton fission (iSF). These materials are distinctive among reported iSF compounds because they exist in the unexplored regime of close spatial proximity but weak electronic coupling between the singlet exciton and triplet pair states. Using transient absorption spectroscopy to investigate photophysics in these molecules, we find that homoconjugated dimers display desirable excited-state dynamics, with significantly reduced recombination rates as compared to conjugated dimers with similar singlet fission rates. In addition, unlike conjugated dimers, the time constants for singlet fission are relatively insensitive to the interplanar angle between chromophores, since rotation about σ bonds negligibly affects the orbital overlap within the π-bonding network. In the nonconjugated dimer, where the iSF occurs with a time constant >10 ns, comparable to the fluorescence lifetime, we used electron spin resonance spectroscopy to unequivocally establish the formation of triplet–triplet multiexcitons and uncoupled triplet excitons through singlet fission. Together, these studies enable us to articulate the role of the conjugation motif in iSF.

Publisher URL: http://dx.doi.org/10.1021/jacs.7b05204

DOI: 10.1021/jacs.7b05204

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.