A transferable model for singlet-fission kinetics

  • A Corrigendum to this article was published on 20 June 2014


Exciton fission is a process that occurs in certain organic materials whereby one singlet exciton splits into two independent triplets. In photovoltaic devices these two triplet excitons can each generate an electron, producing quantum yields per photon of >100% and potentially enabling single-junction power efficiencies above 40%. Here, we measure fission dynamics using ultrafast photoinduced absorption and present a first-principles expression that successfully reproduces the fission rate in materials with vastly different structures. Fission is non-adiabatic and Marcus-like in weakly interacting systems, becoming adiabatic and coupling-independent at larger interaction strengths. In neat films, we demonstrate fission yields near unity even when monomers are separated by >5 Å. For efficient solar cells, however, we show that fission must outcompete charge generation from the singlet exciton. This work lays the foundation for tailoring molecular properties like solubility and energy level alignment while maintaining the high fission yield required for photovoltaic applications.

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Figure 1: Kinetic model of singlet fission.
Figure 2: Summary of theoretical and experimental fission rates.
Figure 3: Prediction of fission rates for a variety of pentacene derivatives.
Figure 4: Impact of fission rate on solar cell performance.

Change history

  • 21 May 2014

    In the version of this Article originally published, the author name Moungi G. Bawendi was missing the middle initial. This has now been corrected in the online versions of the Article.


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This work was supported as part of the Center for Excitonics, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences (award no. DE-SC0001088, MIT). The measurements on pentacene, TIPS-P and DTP were supported by the Engineering and Physical Sciences Research Council. A.R. thanks Corpus Christi College, Cambridge, for a research fellowship. Research was carried out in part at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the US Department of Energy, Office of Basic Energy Sciences (contract no. DE-AC02-98CH10886). The authors thank E. Hontz for discussions, C. Hanson for assistance with spectroscopy and B. Fernandez, T. L. Andrew and L. Liufor help with sample preparation and crystallization.

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T.V.V., M.A.B., J.Y., M.W.B.W. and S.R.Y. designed the experiment and co-wrote the paper. S.R.Y. and D.P.M. performed the density functional theory calculations. J.L., M.W.B.W., A.R., K.J. and M.Y.S. performed the spectroscopy. R.R.P. contributed material synthesis. T.W., N.J.T. and D.N.C. characterized the solar cells. All authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Richard H. Friend or Marc A. Baldo or Troy Van Voorhis.

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Yost, S., Lee, J., Wilson, M. et al. A transferable model for singlet-fission kinetics. Nature Chem 6, 492–497 (2014). https://doi.org/10.1038/nchem.1945

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