Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Efficient solid-state photon upconversion enabled by triplet formation at an organic semiconductor interface

Nature Photonics volume 15, pages 895–900 (2021)Cite this article

Subjects

Abstract

The energy of photons, that is, the wavelength of light, can be upgraded through interactions with materials in a process called photon upconversion1. Although upconversion in organic solids is important for various applications, such as photovoltaics and bioimaging, conventional upconversion systems, based on intersystem crossing (ISC), suffer from low efficiency2,3,4,5,6. Here we report a novel upconversion system with heterojunctions of organic semiconductors. The upconversion occurs through charge separation and recombination, which mediate charge transfer states at the interface. This process can efficiently convert the incident photons to triplets without relying on ISC, which is typically facilitated by the heavy-atom effect1. As a result, a solid-state upconversion system is achieved with an external efficiency that is two orders of magnitude higher than those demonstrated by conventional systems6. Using this result, efficient upconversion, from near-infrared to visible light, can be realized on flexible organic thin films under a weak light-emitting-diode-induced excitation, observable by naked eyes.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: UC mechanism at an organic semiconductor interface.
Fig. 2: UC emission at the D/A interface.
Fig. 3: Optical investigations of UC emission.
Fig. 4: Investigations of the UC mechanism.

Data availability

The main data supporting the findings of this study are available within the article and its Supplementary Information. Extra data are available from the corresponding authors on reasonable request.

References

  1. Zhou, J., Liu, Q., Feng, W., Sun, Y. & Li, F. Upconversion luminescent materials: advances and applications. Chem. Rev. 115, 395–465 (2015).

    Article  Google Scholar 

  2. Gray, V., Moth-Poulsen, K., Albinsson, B. & Abrahamsson, M. Towards efficient solid-state triplet-triplet annihilation based photon upconversion: supramolecular, macromolecular and self-assembled systems. Coord. Chem. Rev. 362, 54–71 (2018).

    Article  Google Scholar 

  3. Joarder, B., Yanai, N. & Kimizuka, N. Solid-state photon upconversion materials: structural integrity and triplet-singlet dual energy migration. J. Phys. Chem. Lett. 9, 4613–4624 (2018).

    Article  Google Scholar 

  4. Tan, G.-R., Wang, M., Hsu, C.-Y., Chen, N. & Zhang, Y. Small upconverting fluorescent nanoparticles for biosensing and bioimaging. Adv. Opt. Mater. 4, 984–997 (2016).

    Article  Google Scholar 

  5. Bharmoria, P., Bildirir, H. & Moth-Poulsen, K. Triplet-triplet annihilation based near infrared to visible molecular photon upconversion. Chem. Soc. Rev. 49, 6529–6554 (2020).

    Article  Google Scholar 

  6. Lin, T. A., Perkinson, C. F. & Baldo, M. A. Strategies for high-performance solid-state triplet-triplet-annihilation-based photon upconversion. Adv. Mater. 32, e1908175 (2020).

    Article  Google Scholar 

  7. Singh-Rachford, T. N. & Castellano, F. N. Photon upconversion based on sensitized triplet-triplet annihilation. Coord. Chem. Rev. 254, 2560–2573 (2010).

    Article  Google Scholar 

  8. Zhou, Y., Castellano, F. N., Schmidt, T. W. & Hanson, K. On the quantum yield of photon upconversion via triplet-triplet annihilation. ACS Energy Lett. 5, 2322–2326 (2020).

    Article  Google Scholar 

  9. Niihori, Y., Wada, Y. & Mitsui, M. Single platinum atom doping to silver clusters enables near-infrared-to-blue photon upconversion. Angew. Chem. Int. Ed. 60, 2822–2827 (2021).

    Article  Google Scholar 

  10. Harada, N., Sasaki, Y., Hosoyamada, M., Kimizuka, N. & Yanai, N. Discovery of key TIPS-naphthalene for efficient visible-to-UV photon upconversion under sunlight and room light. Angew. Chem. Int. Ed. 60, 142–147 (2021).

    Article  Google Scholar 

  11. Wu, M. et al. Solid-state infrared-to-visible upconversion sensitized by colloidal nanocrystals. Nat. Photon. 10, 31–34 (2015).

    Article  ADS  Google Scholar 

  12. Ogawa, T. et al. Donor-acceptor-collector ternary crystalline films for efficient solid-state photon upconversion. J. Am. Chem. Soc. 140, 8788–8796 (2018).

    Article  Google Scholar 

  13. Nakano, K. & Tajima, K. Organic planar heterojunctions: from models for interfaces in bulk heterojunctions to high-performance solar cells. Adv. Mater. 29, 1603269 (2017).

    Article  Google Scholar 

  14. Sarma, M. & Wong, K. T. Exciplex: an intermolecular charge-transfer approach for TADF. ACS Appl. Mater. Interfaces 10, 19279–19304 (2018).

    Article  Google Scholar 

  15. Pandey, A. K. Highly efficient spin-conversion effect leading to energy up-converted electroluminescence in singlet fission photovoltaics. Sci. Rep. 5, 7787 (2015).

    Article  ADS  Google Scholar 

  16. Firdaus, Y. et al. Long-range exciton diffusion in molecular non-fullerene acceptors. Nat. Commun. 11, 5220 (2020).

    Article  ADS  Google Scholar 

  17. Groff, R. P., Merrifield, R. E., Suna, A. & Avakian, P. Magnetic hyperfine modulation of dye-sensitized delayed fluorescence in an organic crystal. Phys. Rev. Lett. 29, 429–431 (1972).

    Article  ADS  Google Scholar 

  18. Rao, A. et al. The role of spin in the kinetic control of recombination in organic photovoltaics. Nature 500, 435–439 (2013).

    Article  ADS  Google Scholar 

  19. Yuan, J. et al. Single-junction organic solar cell with over 15% efficiency using fused-ring acceptor with electron-deficient core. Joule 3, 1140–1151 (2019).

    Article  Google Scholar 

  20. Zhang, H. et al. Over 14% efficiency in organic solar cells enabled by chlorinated nonfullerene small-molecule acceptors. Adv. Mater. 30, e1800613 (2018).

    Article  Google Scholar 

  21. Hiramoto, M., Kikuchi, M. & Izawa, S. Parts-per-million-level doping effects in organic semiconductor films and organic single crystals. Adv. Mater. 31, e1801236 (2019).

    Article  Google Scholar 

  22. Kalyanasundaram, K. & Nazeeruddin, M. K. Tuning of the CT excited state and validity of the energy gap law in mixed ligand complexes of Ru(II) containing 4,4′-dicarboxy-2,2′-bipyridine. Chem. Phys. Lett. 193, 292–297 (1992).

    Article  ADS  Google Scholar 

  23. Benduhn, J. et al. Intrinsic non-radiative voltage losses in fullerene-based organic solar cells. Nat. Energy 2, 17053 (2017).

    Article  ADS  Google Scholar 

  24. Englman, R. & Jortner, J. The energy gap law for radiationless transitions in large molecules. Mol. Phys. 18, 145–164 (1970).

    Article  ADS  Google Scholar 

  25. Monguzzi, A., Mezyk, J., Scotognella, F., Tubino, R. & Meinardi, F. Upconversion-induced fluorescence in multicomponent systems: steady-state excitation power threshold. Phys. Rev. B 78, 195112 (2008).

    Article  ADS  Google Scholar 

  26. Ronchi, A. et al. Triplet-triplet annihilation based photon up-conversion in hybrid molecule-semiconductor nanocrystal systems. Phys. Chem. Chem. Phys. 21, 12353–12359 (2019).

    Article  Google Scholar 

  27. Ronchi, A. et al. High photon upconversion efficiency with hybrid triplet sensitizers by ultrafast hole-routing in electronic-doped nanocrystals. Adv. Mater. 32, e2002953 (2020).

    Article  Google Scholar 

  28. Abulikemu, A. et al. Solid-state, near-infrared to visible photon upconversion via triplet-triplet annihilation of a binary system fabricated by solution casting. ACS Appl. Mater. Interfaces 11, 20812–20819 (2019).

    Article  Google Scholar 

  29. Clarke, T. M. & Durrant, J. R. Charge photogeneration in organic solar cells. Chem. Rev. 110, 6736–6767 (2010).

    Article  Google Scholar 

  30. Proctor, C. M., Albrecht, S., Kuik, M., Neher, D. & Nguyen, T.-Q. Overcoming geminate recombination and enhancing extraction in solution-processed small molecule solar cells. Adv. Energy Mater. 4, 1400230 (2014).

    Article  Google Scholar 

  31. Vandewal, K. et al. Efficient charge generation by relaxed charge-transfer states at organic interfaces. Nat. Mater. 13, 63–68 (2014).

    Article  ADS  Google Scholar 

  32. Izawa, S., Nakano, K., Suzuki, K., Hashimoto, K. & Tajima, K. Dominant effects of first monolayer energetics at donor/acceptor interfaces on organic photovoltaics. Adv. Mater. 27, 3025–3031 (2015).

    Article  Google Scholar 

  33. Perdigon-Toro, L. et al. Barrierless free charge generation in the high-performance PM6:Y6 bulk heterojunction non-fullerene solar cell. Adv. Mater. 32, e1906763 (2020).

    Article  Google Scholar 

  34. Foertig, A. et al. Nongeminate recombination in planar and bulk heterojunction organic solar cells. Adv. Energy Mater. 2, 1483–1489 (2012).

    Article  Google Scholar 

  35. Shintaku, N., Hiramoto, M. & Izawa, S. Effect of trap-assisted recombination on open-circuit voltage loss in phthalocyanine/fullerene solar cells. Org. Electron. 55, 69–74 (2018).

    Article  Google Scholar 

  36. Johnson, R. C. & Merrifield, R. E. Effects of magnetic fields on the mutual annihilation of triplet excitons in anthracene crystals. Phys. Rev. B 1, 896–902 (1970).

    Article  ADS  Google Scholar 

  37. Kawashima, K., Tamai, Y., Ohkita, H., Osaka, I. & Takimiya, K. High-efficiency polymer solar cells with small photon energy loss. Nat. Commun. 6, 10085 (2015).

    Article  ADS  Google Scholar 

  38. Ran, N. A. et al. Harvesting the full potential of photons with organic solar cells. Adv. Mater. 28, 1482–1488 (2016).

    Article  Google Scholar 

  39. Yanai, N. & Kimizuka, N. New triplet sensitization routes for photon upconversion: thermally activated delayed fluorescence molecules, inorganic nanocrystals and singlet-to-triplet absorption. Acc. Chem. Res. 50, 2487–2495 (2017).

    Article  Google Scholar 

  40. Huang, Z., Simpson, D. E., Mahboub, M., Li, X. & Tang, M. L. Ligand enhanced upconversion of near-infrared photons with nanocrystal light absorbers. Chem. Sci. 7, 4101–4104 (2016).

    Article  Google Scholar 

  41. Di, D. et al. Efficient triplet exciton fusion in molecularly doped polymer light-emitting diodes. Adv. Mater. 29, 1605987 (2017).

    Article  Google Scholar 

  42. Izawa, S., Shintaku, N., Kikuchi, M. & Hiramoto, M. Importance of interfacial crystallinity to reduce open-circuit voltage loss in organic solar cells. Appl. Phys. Lett. 115, 153301 (2019).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

This research was supported in part by JSPS KAKENHI, Grant-in-Aid for Young Scientists no. 18K14115 (S.I.), the Mazda Foundation (S.I.), the Kao Foundation for Arts and Sciences (S.I.) and Konica Minolta Science and Technology Foundation (S.I.). We thank T. Ueda from the Instrument Center in the Institute for Molecular Science for his assistance with most of the optical measurements. We thank K. Tajima and K. Nakano (RIKEN) for assistance with the highly sensitive EQE measurements of photovoltaic devices. We also thank K. Tajima (RIKEN) and M. Takahashi (Shizuoka University) for their valuable comments.

Author information

Authors and Affiliations

  1. Institute for Molecular Science, Okazaki, Aichi, Japan

    Seiichiro Izawa & Masahiro Hiramoto

  2. The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi, Japan

    Seiichiro Izawa & Masahiro Hiramoto

Authors
  1. Seiichiro Izawa
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Masahiro Hiramoto
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

S.I. directed the project, conceived the idea, designed and performed the experiments and wrote the paper. M.H. supervised the research. Both authors reviewed the manuscript.

Corresponding author

Correspondence to Seiichiro Izawa.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Photonics thanks the anonymous reviewers for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Materials and Methods, Supplementary Figs. 1–7, Tables 1 and 2 and Discussion.

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Izawa, S., Hiramoto, M. Efficient solid-state photon upconversion enabled by triplet formation at an organic semiconductor interface. Nat. Photon. 15, 895–900 (2021). https://doi.org/10.1038/s41566-021-00904-w

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41566-021-00904-w

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing