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Impact of non-equilibrium molecular packings on singlet fission in microcrystals observed using 2D white-light microscopy

Nature Chemistry volume 12, pages 40–47 (2020)Cite this article

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Abstract

Singlet fission, the process of splitting a singlet exciton into two triplet excitons, has been proposed as a mechanism for improving the efficiency of future photovoltaic devices. In organic semiconductors exhibiting singlet fission, the geometric relationship between molecules plays an important role by setting the intermolecular couplings that determine the system energetics. Here, we spatially image TIPS-pentacene microcrystals using ultrafast two-dimensional white-light microscopy and discover a low-energy singlet state sparsely distributed throughout the microcrystals, with higher concentrations at edges and morphological defects. The spectra of these singlet states are consistent with slip-stacked molecular geometries and increased charge-transfer couplings. The picosecond-timescale kinetics of these low-energy singlet states matches that of the correlated triplet-pair state, which we attribute to singlet/triplet-pair interconversion at these sites. Our observations support the conclusion that small populations of geometries with favourable energetics can play outsized roles in singlet fission processes.

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Fig. 1: Probing energy levels using 2DWL spectroscopy.
Fig. 2: Broadband TA imaging of individual microcrystals.
Fig. 3: Characterization of morphological defects.
Fig. 4: Kinetic characterization via broadband TA.

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Data availability

The experimental data with corresponding spectral simulations are available from the authors upon request.

Code availability

The MATLAB codes used for data analysis and simulations are available from the authors upon request.

References

  1. Smith, M. B. & Michl, J. Singlet fission. Chem. Rev. 110, 6891–6936 (2010).

    CAS  PubMed  Google Scholar 

  2. Shockley, W. & Queisser, H. J. Detailed balance limit of efficiency of p–n junction solar cells. J. Appl. Phys. 32, 510–519 (1961).

    CAS  Google Scholar 

  3. Ramanan, C., Smeigh, A. L., Anthony, J. E., Marks, T. J. & Wasielewski, M. R. Competition between singlet fission and charge separation in solution-processed blend films of 6,13-bis(triisopropylsilylethynyl)pentacene with sterically-encumbered perylene-3,4:9,10-bis(dicarboximide)s. J. Am. Chem. Soc. 134, 386–397 (2012).

    CAS  PubMed  Google Scholar 

  4. Walker, B. J., Musser, A. J., Beljonne, D. & Friend, R. H. Singlet exciton fission in solution. Nat. Chem. 5, 1019–1024 (2013).

    CAS  PubMed  Google Scholar 

  5. Congreve, D. N. et al. External quantum efficiency above 100% in a singlet-exciton-fission-based organic photovoltaic cell. Science 340, 334–337 (2013).

    CAS  PubMed  Google Scholar 

  6. Yang, L. et al. Solution-processable singlet fission photovoltaic devices. Nano Lett. 15, 354–358 (2015).

    CAS  PubMed  Google Scholar 

  7. Pazos-Outon, L. M. et al. A silicon-singlet fission tandem solar cell exceeding 100% external quantum efficiency with high spectral stability. ACS Energy Lett. 2, 476–480 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  8. Zhu, T., Wan, Y., Guo, Z., Johnson, J. & Huang, L. Two birds with one stone: tailoring singlet fission for both triplet yield and exciton diffusion length. Adv. Mater. 28, 7539–7547 (2016).

    CAS  PubMed  Google Scholar 

  9. Wan, Y. et al. Cooperative singlet and triplet exciton transport in tetracene crystals visualized by ultrafast microscopy. Nat. Chem. 7, 785–792 (2015).

    CAS  PubMed  Google Scholar 

  10. Wong, C. Y. et al. Revealing exciton dynamics in a small-molecule organic semiconducting film with subdomain transient absorption microscopy. J. Phys. Chem. C 117, 22111–22122 (2013).

    CAS  Google Scholar 

  11. Wong, C. Y., Cotts, B. L., Wu, H. & Ginsberg, N. S. Exciton dynamics reveal aggregates with intermolecular order at hidden interfaces in solution-cast organic semiconducting films. Nat. Commun. 6, 5946 (2015).

    CAS  PubMed  Google Scholar 

  12. Folie, B. D., Haber, J. B., Refaely-Abramson, S., Neaton, J. B. & Ginsberg, N. S. Long-lived correlated triplet pairs in a π-stacked crystalline pentacene derivative. J. Am. Chem. Soc. 140, 2326–2335 (2018).

    CAS  PubMed  Google Scholar 

  13. Piland, G. B. & Bardeen, C. J. How morphology affects singlet fission in crystalline tetracene. J. Phys. Chem. Lett. 6, 1841–1846 (2015).

    CAS  PubMed  Google Scholar 

  14. Tayebjee, M. J. Y. et al. Morphological evolution and singlet fission in aqueous suspensions of TIPS-pentacene nanoparticles. J. Phys. Chem. C 120, 157–165 (2016).

    CAS  Google Scholar 

  15. Pensack, R. D. et al. Exciton delocalization drives rapid singlet fission in nanoparticles of acene derivatives. J. Am. Chem. Soc. 137, 6790–6803 (2015).

    CAS  PubMed  Google Scholar 

  16. Roberts, S. T. et al. Efficient singlet fission found in a disordered acene film. J. Am. Chem. Soc. 134, 6388–6400 (2012).

    CAS  PubMed  Google Scholar 

  17. Schnedermann, C. et al. Sub-10 fs time-resolved vibronic optical microscopy. J. Phys. Chem. Lett. 7, 4854–4859 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  18. Broch, K. et al. Robust singlet fission in pentacene thin films with tuned charge transfer interactions. Nat. Commun. 9, 954 (2018).

    CAS  PubMed  PubMed Central  Google Scholar 

  19. Eaton, S. W. et al. Singlet exciton fission in polycrystalline thin films of a slip-stacked perylenediimide. J. Am. Chem. Soc. 135, 14701–14712 (2013).

    CAS  PubMed  Google Scholar 

  20. Sanders, S. N. et al. Quantitative intramolecular singlet fission in bipentacenes. J. Am. Chem. Soc. 137, 8965–8972 (2015).

    CAS  PubMed  Google Scholar 

  21. Zirzlmeier, J. et al. Singlet fission in pentacene dimers. Proc. Natl Acad. Sci. USA 112, 5325–5330 (2015).

    CAS  PubMed  Google Scholar 

  22. Kumarasamy, E. et al. Tuning singlet fission in π-bridge-π chromophores. J. Am. Chem. Soc. 139, 12488–12494 (2017).

    CAS  PubMed  Google Scholar 

  23. Nagarajan, K., Mallia, A. R., Reddy, V. S. & Hariharan, M. Access to triplet excited state in core-twisted perylenediimide. J. Phys. Chem. C 120, 8443–8450 (2016).

    CAS  Google Scholar 

  24. Korovina, N. V. et al. Singlet fission in a covalently linked cofacial alkynyltetracene dimer. J. Am. Chem. Soc. 138, 617–627 (2016).

    CAS  PubMed  Google Scholar 

  25. Bhattacharyya, K. & Datta, A. Polymorphism controlled singlet fission in TIPS-anthracene: role of stacking orientation. J. Phys. Chem C 121, 1412–1420 (2017).

    CAS  Google Scholar 

  26. Arias, D. H., Ryerson, J. L., Cook, J. D., Damrauer, N. H. & Johnson, J. C. Polymorphism influences singlet fission rates in tetracene thin films. Chem. Sci. 7, 1185–1191 (2016).

    CAS  PubMed  Google Scholar 

  27. Mou, W. W., Hattori, S., Rajak, P., Shimojo, F. & Nakano, A. Nanoscopic mechanisms of singlet fission in amorphous molecular solid. Appl. Phys. Lett. 102, 173301 (2013).

    Google Scholar 

  28. Grieco, C. et al. Harnessing molecular vibrations to probe triplet dynamics during singlet fission. J. Phys. Chem. Lett. 8, 5700–5706 (2017).

    CAS  PubMed  Google Scholar 

  29. Grieco, C. et al. Triplet transfer mediates triplet pair separation during singlet fission in 6,13-bis(triisopropylsilylethynyl)-pentacene. Adv. Funct. Mater. 27, 1703929 (2017).

    Google Scholar 

  30. Grieco, C. et al. Direct observation of correlated triplet pair dynamics during singlet fission using ultrafast mid-IR spectroscopy. J. Phys. Chem. C 122, 2012–2022 (2018).

    CAS  Google Scholar 

  31. Miyata, K., Conrad-Burton, F. S., Geyer, F. L. & Zhu, X. Y. Triplet pair states in singlet fission. Chem. Rev. 119, 4261–4292 (2019).

    CAS  PubMed  Google Scholar 

  32. Bakulin, A. A. et al. Real-time observation of multiexcitonic states in ultrafast singlet fission using coherent 2D electronic spectroscopy. Nat. Chem. 8, 16–23 (2016).

    CAS  PubMed  Google Scholar 

  33. Herz, J. et al. Unveiling singlet fission mediating states in TIPS-pentacene and its aza derivatives. J. Phys. Chem. A 119, 6602–6610 (2015).

    CAS  PubMed  Google Scholar 

  34. Pensack, R. D. et al. Solution-processable, crystalline material for quantitative singlet fission. Mater. Horizons 4, 915–923 (2017).

    CAS  Google Scholar 

  35. Yong, C. K. et al. The entangled triplet pair state in acene and heteroacene materials. Nat. Commun. 8, 15953 (2017).

    CAS  PubMed  PubMed Central  Google Scholar 

  36. Grieco, C. et al. Dynamic exchange during triplet transport in nanocrystalline TIPS-pentacene films. J. Am. Chem. Soc. 138, 16069–16080 (2016).

    CAS  PubMed  Google Scholar 

  37. Grechko, M. & Zanni, M. T. Quantification of transition dipole strengths using 1D and 2D spectroscopy for the identification of molecular structures via exciton delocalization: application to α-helices. J. Chem. Phys. 137, 184202 (2012).

    PubMed  PubMed Central  Google Scholar 

  38. Anthony, J. E., Brooks, J. S., Eaton, D. L. & Parkin, S. R. Functionalized pentacene: improved electronic properties from control of solid-state order. J. Am. Chem. Soc. 123, 9482–9483 (2001).

    CAS  PubMed  Google Scholar 

  39. Gomar-Nadal, E., Conrad, B. R., Cullen, W. G. & Willams, E. A. Effect of impurities on pentacene thin film growth for field-effect transistors. J. Phys. Chem. C 112, 5646–5650 (2008).

    CAS  Google Scholar 

  40. Conrad, B. R. et al. Effect of impurities on pentacene island nucleation. Phys. Rev. B 77, 205328 (2008).

    Google Scholar 

  41. Monahan, N. & Zhu, X. Y. Charge transfer-mediated singlet fission. Annu. Rev. Phys. Chem. 66, 601–618 (2015).

    CAS  PubMed  Google Scholar 

  42. Diao, Y. et al. Understanding polymorphism in organic semiconductor thin films through nanoconfinement. J. Am. Chem. Soc. 136, 17046–17057 (2014).

    CAS  PubMed  Google Scholar 

  43. Wang, L., Olivier, Y., Prezhdo, O. V. & Beljonne, D. Maximizing singlet fission by intermolecular packing. J. Phys. Chem. Lett. 5, 3345–3353 (2014).

    CAS  PubMed  Google Scholar 

  44. Wilson, M. W. et al. Ultrafast dynamics of exciton fission in polycrystalline pentacene. J. Am. Chem. Soc. 133, 11830–11833 (2011).

    CAS  PubMed  Google Scholar 

  45. Tuan Trinh, M. et al. Distinct properties of the triplet pair state from singlet fission. Sci. Adv. 3, e1700241 (2017).

    PubMed  PubMed Central  Google Scholar 

  46. Pensack, R. D. et al. Observation of two triplet-pair intermediates in singlet exciton fission. J. Phys. Chem. Lett. 7, 2370–2375 (2016).

    CAS  PubMed  Google Scholar 

  47. Loukianov, A. et al. Two-dimensional electronic stark spectroscopy. J. Phys. Chem. Lett. 8, 679–683 (2017).

    CAS  PubMed  Google Scholar 

  48. Bussolotti, F., Kera, S. & Ueno, N. Potassium doping of single crystalline pentacene thin film. Phys. Rev. B 86, 155120 (2012).

    Google Scholar 

  49. Roth, F. & Knupfer, M. Impact of potassium doping on the electronic structure of tetracene and pentacene: an electron energy-loss study. J. Chem. Phys. 143, 154708 (2015).

    PubMed  Google Scholar 

  50. McDonough, T. J. et al. Triplet exciton dissociation and electron extraction in graphene-templated pentacene observed with ultrafast spectroscopy. Phys. Chem. Chem. Phys. 19, 4809–4820 (2017).

    CAS  PubMed  Google Scholar 

  51. Di, D. et al. Efficient triplet exciton fusion in molecularly doped polymer light-emitting diodes. Adv. Mater. 29, 1–7 (2017).

    Google Scholar 

  52. Burgos, J., Pope, M., Swenberg, C. E. & Alfano, R. R. Heterofission in pentacene-doped tetracene single crystals. Phys. Status Solidi B 83, 249–256 (1977).

    CAS  Google Scholar 

  53. Stern, H. L. et al. Identification of a triplet pair intermediate in singlet exciton fission in solution. Proc. Natl Acad. Sci. USA 112, 7656–7661 (2015).

    CAS  PubMed  Google Scholar 

  54. Kearns, N. M., Mehlenbacher, R. D., Jones, A. C. & Zanni, M. T. Broadband 2D electronic spectrometer using white light and pulse shaping: noise and signal evaluation at 1 and 100 kHz. Opt. Express. 25, 7869–7883 (2017).

    CAS  PubMed  Google Scholar 

  55. Sharifzadeh, S. et al. Relating the physical structure and optoelectronic function of crystalline TIPS-pentacene. Adv. Funct. Mater. 25, 2038–2046 (2015).

    CAS  Google Scholar 

  56. Yamagata, H. et al. The nature of singlet excitons in oligoacene molecular crystals. J. Chem. Phys. 134, 204703 (2011).

    CAS  PubMed  Google Scholar 

  57. Kistler, K. A., Pochas, C. M., Yamagata, H., Matsika, S. & Spano, F. C. Absorption, circular dichroism and photoluminescence in perylene diimide bichromophores: polarization-dependent H- and J-aggregate behavior. J. Phys. Chem. B 116, 77–86 (2012).

    CAS  PubMed  Google Scholar 

  58. Hestand, N. J. et al. Polarized absorption in crystalline pentacene: theory vs experiment. J. Phys. Chem. C 119, 22137–22147 (2015).

    CAS  Google Scholar 

  59. Hestand, N. J. & Spano, F. C. Molecular aggregate photophysics beyond the Kasha model: novel design principles for organic materials. Acc. Chem. Res. 50, 341–350 (2017).

    CAS  PubMed  Google Scholar 

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Acknowledgements

This research was supported by NSF CHE 1665110 and AFOSR FA9550-15-1-0061.

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  1. Department of Chemistry, University of Wisconsin, Madison, WI, USA

    Andrew C. Jones, Nicholas M. Kearns, Jia-Jung Ho, Jessica T. Flach & Martin T. Zanni

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  1. Andrew C. Jones
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Contributions

A.C.J., M.T.Z., N.M.K. and J.T.F. designed the experiment. A.C.J., N.M.K. and J.T.F. performed the measurements. A.C.J., N.M.K. and J.-J.H. performed the data analysis and modelling. A.C.J. and M.T.Z. wrote the manuscript.

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Correspondence to Martin T. Zanni.

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M.T.Z. is an owner of PhaseTech Spectroscopy, Inc., which sells 2D spectrometers and pulse shapers.

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Supplementary Figs. 1–16, Supplementary data and analysis and Supplementary methods.

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Jones, A.C., Kearns, N.M., Ho, JJ. et al. Impact of non-equilibrium molecular packings on singlet fission in microcrystals observed using 2D white-light microscopy. Nat. Chem. 12, 40–47 (2020). https://doi.org/10.1038/s41557-019-0368-9

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