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.

  • Letter
  • Published:

Carbazole isomers induce ultralong organic phosphorescence

Nature Materials volume 20, pages 175–180 (2021)Cite this article

Subjects

Abstract

Commercial carbazole has been widely used to synthesize organic functional materials that have led to recent breakthroughs in ultralong organic phosphorescence1, thermally activated delayed fluorescence2,3, organic luminescent radicals4 and organic semiconductor lasers5. However, the impact of low-concentration isomeric impurities present within commercial batches on the properties of the synthesized molecules requires further analysis. Here, we have synthesized highly pure carbazole and observed that its fluorescence is blueshifted by 54 nm with respect to commercial samples and its room-temperature ultralong phosphorescence almost disappears6. We discover that such differences are due to the presence of a carbazole isomeric impurity in commercial carbazole sources, with concentrations <0.5 mol%. Ten representative carbazole derivatives synthesized from the highly pure carbazole failed to show the ultralong phosphorescence reported in the literature1,7,8,9,10,11,12,13,14,15. However, the phosphorescence was recovered by adding 0.1 mol% isomers, which act as charge traps. Investigating the role of the isomers may therefore provide alternative insights into the mechanisms behind ultralong organic phosphorescence1,6,7,8,9,10,11,12,13,14,15,16,17,18.

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

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

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

Fig. 1: Paradox of the ultralong phosphorescence of carbazole.
Fig. 2: Impurity effect on carbazole derivatives.
Fig. 3: Emission characteristics with different isomer doping concentrations.
Fig. 4: Transient absorption, photoluminescence and ultralong phosphorescence mechanism.

Similar content being viewed by others

Data availability

The data that support the findings of this study are available from C.C. and L.B. upon reasonable request. The X-ray crystallographic data for the structures reported here have been deposited at the Cambridge Crystallographic Data Centre (CCDC) under deposition numbers CCDC 1953802–1953811 and 2019581–2019589. These data can be obtained free of charge from the Cambridge Crystallographic Data Centre at www.ccdc.cam.ac.uk/data_request/cif. Source data are provided with this paper.

References

  1. An, Z. et al. Stabilizing triplet excited states for ultralong organic phosphorescence. Nat. Mater. 14, 685–690 (2015).

    Article  CAS  Google Scholar 

  2. Uoyama, H., Goushi, K., Shizu, K., Nomura, H. & Adachi, C. Highly efficient organic light-emitting diodes from delayed fluorescence. Nature 492, 234–238 (2012).

    Article  CAS  Google Scholar 

  3. Hamze, R. et al. Eliminating nonradiative decay in Cu(I) emitters: >99% quantum efficiency and microsecond lifetime. Science 363, 601–606 (2019).

    Article  CAS  Google Scholar 

  4. Ai, X. et al. Efficient radical-based light-emitting diodes with doublet emission. Nature 563, 536–540 (2018).

    Article  CAS  Google Scholar 

  5. Sandanayaka, A. S. D. et al. Indication of current-injection lasing from an organic semiconductor. Appl. Phys. Express 12, 061010 (2019).

    Article  CAS  Google Scholar 

  6. Bilen, C. S., Harrison, N. & Morantz, D. J. Unusual room temperature afterglow in some crystalline organic compounds. Nature 271, 235–237 (1978).

    Article  CAS  Google Scholar 

  7. Cai, S. et al. Visible-light-excited ultralong organic phosphorescence by manipulating intermolecular interactions. Adv. Mater. 29, 1701244 (2017).

    Article  Google Scholar 

  8. Xie, Y. et al. How the molecular packing affects the room temperature phosphorescence in pure organic compounds: ingenious molecular design, detailed crystal analysis, and rational theoretical calculations. Adv. Mater. 29, 1606829 (2017).

    Article  Google Scholar 

  9. Xiong, Y. et al. Designing efficient and ultralong pure organic room-temperature phosphorescent materials by structural isomerism. Angew. Chem. Int. Ed. 57, 7997–8001 (2018).

    Article  CAS  Google Scholar 

  10. Zhang, T. et al. Pure organic persistent room-temperature phosphorescence at both crystalline and amorphous states. ChemPhysChem 19, 2389–2396 (2018).

    Article  CAS  Google Scholar 

  11. Gong, Y. et al. Achieving persistent room temperature phosphorescence and remarkable mechanochromism from pure organic luminogens. Adv. Mater. 27, 6195–6201 (2015).

    Article  CAS  Google Scholar 

  12. Yang, Z. et al. Intermolecular electronic coupling of organic units for efficient persistent room-temperature phosphorescence. Angew. Chem. Int. Ed. 55, 2181–2185 (2016).

    Article  CAS  Google Scholar 

  13. Fateminia, S. M. A. et al. Organic nanocrystals with bright red persistent room-temperature phosphorescence for biological applications. Angew. Chem. Int. Ed. 56, 12160–12164 (2017).

    Article  CAS  Google Scholar 

  14. Kenry, Chen,C. & Liu, B. Enhancing the performance of pure organic room-temperature phosphorescent luminophores. Nat. Commun. 10, 2111 (2019).

    Article  CAS  Google Scholar 

  15. Xue, P. et al. Correction: Bright persistent luminescence from pure organic molecules through a moderate intermolecular heavy atom effect. Chem. Sci. 8, 6691–6691 (2017).

    Article  CAS  Google Scholar 

  16. Gu, L. et al. Dynamic ultralong organic phosphorescence by photoactivation. Angew. Chem. Int. Ed. 57, 8425–8431 (2018).

    Article  CAS  Google Scholar 

  17. Zhao, W. et al. Boosting the efficiency of organic persistent room-temperature phosphorescence by intramolecular triplet-triplet energy transfer. Nat. Commun. 10, 1595 (2019).

    Article  Google Scholar 

  18. Mao, Z. et al. Two-photon-excited ultralong organic room temperature phosphorescence by dual-channel triplet harvesting. Chem. Sci. 10, 7352–7357 (2019).

    Article  CAS  Google Scholar 

  19. Li, Y., Gecevicius, M. & Qiu, J. Long persistent phosphors—from fundamentals to applications. Chem. Soc. Rev. 45, 2090–2136 (2016).

    Article  CAS  Google Scholar 

  20. Kabe, R. & Adachi, C. Organic long persistent luminescence. Nature 550, 384–387 (2017).

    Article  CAS  Google Scholar 

  21. Lastusaari, M. et al. The Bologna Stone: history’s first persistent luminescent material. Eur. J. Miner. 24, 885–890 (2012).

    Article  CAS  Google Scholar 

  22. Matsuzawa, T., Aoki, Y., Takeuchi, N. & Murayama, Y. A new long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+,Dy3+. J. Electrochem. Soc. 143, 2670–2673 (1996).

    Article  CAS  Google Scholar 

  23. Clapp, D. B. The phosphorescence of tetraphenylmethane and certain related substances. J. Am. Chem. Soc. 61, 523–524 (1939).

    Article  CAS  Google Scholar 

  24. Graebe, C. & Glaser, C. Ber. Dtsch. Chem. Ges. 5, 12 (1872).

    Google Scholar 

  25. Feng, H. et al. Tuning molecular emission of organic emitters from fluorescence to phosphorescence through push-pull electronic effects. Nat. Commun. 11, 2617 (2020).

    Article  CAS  Google Scholar 

  26. Chen, C. et al. Intramolecular charge transfer controls switching between room temperature phosphorescence and thermally activated delayed fluorescence. Angew. Chem. Int. Ed. 57, 16407–16411 (2018).

    Article  CAS  Google Scholar 

  27. Noda, H. et al. Critical role of intermediate electronic states for spin-flip processes in charge-transfer-type organic molecules with multiple donors and acceptors. Nat. Mater. 18, 1084–1090 (2019).

    Article  CAS  Google Scholar 

  28. Bolton, O., Lee, K., Kim, H.-J., Lin, K. Y. & Kim, J. Activating efficient phosphorescence from purely organic materials by crystal design. Nat. Chem. 3, 205–210 (2011).

    Article  CAS  Google Scholar 

  29. Ullah, E., McNulty, J. & Robertson, A. Highly chemoselective mono-Suzuki arylation reactions on all three dichlorobenzene isomers and applications development. Eur. J. Org. Chem. 2012, 2127–2131 (2012).

    Article  CAS  Google Scholar 

  30. Yang, L., Zhang, Y., Zou, X., Lu, H. & Li, G. Visible-light-promoted intramolecular C–H amination in aqueous solution: synthesis of carbazole. Green. Chem. 20, 1362–1366 (2018).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This study was supported by the Singapore National Research Foundation (NRF) Competitive Research Program (R279-000-483-281), the NRF Investigatorship (R279-000-444-281) and the National University of Singapore (R279-000-482-133).

Author information

Authors and Affiliations

  1. Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore

    Chengjian Chen, Kok Chan Chong & Bin Liu

  2. School of Chemistry, Sun Yat-sen University, Guangzhou, China

    Zhenguo Chi, Zhan Yang, Zhu Mao & Zhiyong Yang

  3. Department of Chemistry, Durham University, Durham, UK

    Andrei S. Batsanov

  4. Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Fuzhou, China

    Bin Liu

Authors
  1. Chengjian Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Zhenguo Chi
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Kok Chan Chong
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Andrei S. Batsanov
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Zhan Yang
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Zhu Mao
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Zhiyong Yang
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Bin Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

C.C. and B.L. designed the experiments. C.C. optimized the HPLC and grew crystals. C.C., Z.C., Z.Y., Z.M. and Z.Y. contributed to the optical characterizations. C.C. and K.C.C. synthesized all compounds. A.S.B. and C.C. solved the crystal structures. C.C. and B.L. discussed the results and drafted the manuscript. B.L. supervised the project. All authors contributed to the proofreading of the manuscript.

Corresponding author

Correspondence to Bin Liu.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Supplementary information

Supplementary Information

Supplementary methods, Scheme 1, Figs. 1–37 and Tables 1–11.

Source data

Source Data Fig. 1

HPLC spectra of TCI-Cz.

Source Data Fig. 2

HPLC spectra monitored at the onset absorption of 346 nm for Cz and 354 nm for CPhCz.

Source Data Fig. 3

Emission characteristics with different isomer doping concentrations.

Source Data Fig. 4

Transient absorption and photoluminescence.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Chen, C., Chi, Z., Chong, K.C. et al. Carbazole isomers induce ultralong organic phosphorescence. Nat. Mater. 20, 175–180 (2021). https://doi.org/10.1038/s41563-020-0797-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41563-020-0797-2

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