Geminate and non-geminate recombination of triplet excitons formed by singlet fission

ORAL

Abstract

Singlet fission is a promising route to enhance solar cells by harvesting two electron-hole pairs from high-energy photons. Through singlet fission, an optically generated singlet exciton is transformed into two spin-correlated triplet excitons, which serve as a unique signature of the process. We use optically detected magnetic resonance to identify and study triplet excitons created through singlet fission in the solution-processable small molecule TIPS-tetracene (bis(triisopropylsilylethynyl)tetracene). Through changes in photoluminescence under spin resonance, we identify geminate recombination of triplet pairs directly following singlet fission, as well as recombination from bimolecular triplet-triplet annihilation. We show that both processes can be present in spin-coated films, and correlate the two distinct annihilation pathways to film morphology.

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Authors

  • Sam L. Bayliss

    • Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.

  • Alexei Chepelianskii

    • Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.

  • Alessandro Sepe

    • Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.

  • Bruno Ehrler

    • Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.

  • Brian J. Walker

    • Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.

  • Matt J. Bruzek

    • Department of Chemistry, University of Kentucky, Lexington, KY 40506 (USA)

  • John E. Anthony

    • Department of Chemistry, University of Kentucky, Lexington, KY 40506 (USA)

  • Neil C. Greenham

    • Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, U.K.