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:

Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots

Nature Nanotechnology volume 15, pages 668–674 (2020)Cite this article

Subjects

Abstract

Colloidal quantum dot (QD) solids are emerging semiconductors that have been actively explored in fundamental studies of charge transport1 and for applications in optoelectronics2. Forming high-quality QD solids—necessary for device fabrication—requires substitution of the long organic ligands used for synthesis with short ligands that provide increased QD coupling and improved charge transport3. However, in perovskite QDs, the polar solvents used to carry out the ligand exchange decompose the highly ionic perovskites4. Here we report perovskite QD resurfacing to achieve a bipolar shell consisting of an inner anion shell, and an outer shell comprised of cations and polar solvent molecules. The outer shell is electrostatically adsorbed to the negatively charged inner shell. This approach produces strongly confined perovskite QD solids that feature improved carrier mobility (≥0.01 cm2 V−1 s−1) and reduced trap density relative to previously reported low-dimensional perovskites. Blue-emitting QD films exhibit photoluminescence quantum yields exceeding 90%. By exploiting the improved mobility, we have been able to fabricate CsPbBr3 QD-based efficient blue and green light-emitting diodes. Blue devices with reduced trap density have an external quantum efficiency of 12.3%; the green devices achieve an external quantum efficiency of 22%.

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: Bipolar-shell resurfacing of perovskite QDs.
Fig. 2: Chemistry and photophysics of bipolar-shell-stabilized CsPbBr3 perovskite QDs.
Fig. 3: Properties of CsPbBr3 perovskite QD solid films cast from bipolar-shell-resurfaced QD inks.
Fig. 4: Blue and green LEDs based on perovskite QD solids.

Similar content being viewed by others

Data availability

The authors declare that the main data supporting the findings of this study are available within the letter and its Supplementary Information. Extra data are available from the corresponding authors upon reasonable request.

References

  1. Kagan, C. R. & Murray, C. B. Charge transport in strongly coupled quantum dot solids. Nat. Nanotechnol. 10, 1013–1026 (2015).

    Article  CAS  Google Scholar 

  2. A decade of perovskite photovoltaics. Nat. Energy 4, 1 (2019).

  3. Kagan, C. R., Lifshitz, E., Sargent, E. H. & Talapin, D. V. Building devices from colloidal quantum dots. Science 353, 885–892 (2016).

    Article  CAS  Google Scholar 

  4. Kovalenko, M. V., Protesescu, L. & Bodnarchuk, M. I. Properties and potential optoelectronic applications of lead halide perovskite nanocrystals. Science 358, 745–750 (2017).

    Article  CAS  Google Scholar 

  5. Yuan, M. et al. Perovskite energy funnels for efficient light-emitting diodes. Nat. Nanotechnol. 11, 872–877 (2016).

    Article  CAS  Google Scholar 

  6. Liu, Y. et al. Efficient blue light-emitting diodes based on quantum-confined bromide perovskite nanostructures. Nat. Photon. 13, 760–764 (2019).

    Article  CAS  Google Scholar 

  7. Chiba, T. et al. Anion-exchange red perovskite quantum dots with ammonium iodine salts for highly efficient light-emitting devices. Nat. Photon. 12, 681–687 (2018).

    Article  CAS  Google Scholar 

  8. Nedelcu, G. et al. Fast anion-exchange in highly luminescent nanocrystals of cesium lead halide perovskites (CsPbX3, X = Cl, Br, I). Nano Lett. 15, 5635–5640 (2015).

    Article  CAS  Google Scholar 

  9. Akkerman, Q. A. et al. Tuning the optical properties of cesium lead halide perovskite nanocrystals by anion exchange reactions. J. Am. Chem. Soc. 137, 10276–10281 (2015).

    Article  CAS  Google Scholar 

  10. Kovalenko, M. V., Scheele, M. & Talapin, D. V. Colloidal nanocrystals with molecular metal chalcogenide surface ligands. Science 324, 1417–1420 (2009).

    Article  CAS  Google Scholar 

  11. Boles, M. A., Ling, D., Hyeon, T. & Talapin, D. V. The surface science of nanocrystals. Nat. Mater. 15, 141–153 (2016).

    Article  CAS  Google Scholar 

  12. Bodnarchuk, M. I. et al. Rationalizing and controlling the surface structure and electronic passivation of cesium lead halide nanocrystals. ACS Energy Lett. 4, 63–74 (2019).

    Article  CAS  Google Scholar 

  13. De Roo, J. et al. Highly dynamic ligand binding and light absorption coefficient of cesium lead bromide perovskite nanocrystals. ACS Nano. 10, 2071–2081 (2016).

    Article  Google Scholar 

  14. Krieg, F. et al. Colloidal CsPbX3 (X = Cl, Br, I) nanocrystals 2.0: zwitterionic capping ligands for improved durability and stability. ACS Energy Lett. 3, 641–646 (2018).

    Article  CAS  Google Scholar 

  15. Dong, Y. et al. Precise control of quantum confinement in cesium lead halide perovskite quantum dots via thermodynamic equilibrium. Nano Lett. 18, 3716–3722 (2018).

    Article  CAS  Google Scholar 

  16. Nenon, D. P. et al. Design principles for trap-free CsPbX3 nanocrystals: enumerating and eliminating surface halide vacancies with softer Lewis bases. J. Am. Chem. Soc. 140, 17760–17772 (2018).

    Article  CAS  Google Scholar 

  17. Pan, J. et al. Highly efficient perovskite-quantum-dot light-emitting diodes by surface engineering. Adv. Mater. 28, 8718–8725 (2016).

    Article  CAS  Google Scholar 

  18. Wu, K. et al. Ultrafast interfacial electron and hole transfer from CsPbBr3 perovskite quantum dots. J. Am. Chem. Soc. 137, 12792–12795 (2015).

    Article  CAS  Google Scholar 

  19. Becker, M. A. et al. Bright triplet excitons in caesium lead halide perovskites. Nature 553, 189–193 (2018).

    Article  CAS  Google Scholar 

  20. Tao, S. et al. Absolute energy level positions in tin- and lead-based halide perovskites. Nat. Commun. 10, 2560 (2019).

    Article  Google Scholar 

  21. Gong, X. et al. Contactless measurements of photocarrier transport properties in perovskite single crystals. Nat. Commun. 10, 1591 (2019).

    Article  Google Scholar 

  22. Whitham, K. et al. Charge transport and localization in atomically coherent quantum dot solids. Nat. Mater. 15, 557–563 (2016).

    Article  CAS  Google Scholar 

  23. Li, Z. et al. Modulation of recombination zone position for quasi-two-dimensional blue perovskite light-emitting diodes with efficiency exceeding 5%. Nat. Commun. 10, 1027 (2019).

    Article  Google Scholar 

  24. Leijtens, T. et al. Carrier trapping and recombination: the role of defect physics in enhancing the open circuit voltage of metal halide perovskite solar cells. Energy Environ. Sci. 9, 3472–3481 (2016).

    Article  CAS  Google Scholar 

  25. Hou, S., Gangishetty, M. K., Quan, Q. & Congreve, D. N. Efficient blue and white perovskite light-emitting diodes via manganese doping. Joule 2, 2421–2433 (2018).

    Article  CAS  Google Scholar 

  26. Xing, J. et al. Color-stable highly luminescent sky-blue perovskite light-emitting diodes. Nat. Commun. 9, 3541 (2018).

    Article  Google Scholar 

  27. Chiba, T. et al. High-efficiency perovskite quantum-dot light-emitting devices by effective washing process and interfacial energy level alignment. ACS Appl. Mater. Interfaces 9, 18054–18060 (2017).

    Article  CAS  Google Scholar 

  28. Gong, X. et al. Highly efficient quantum dot near-infrared light-emitting diodes. Nat. Photon. 10, 253–257 (2016).

    Article  CAS  Google Scholar 

  29. Shen, H. et al. Visible quantum dot light-emitting diodes with simultaneous high brightness and efficiency. Nat. Photon. 13, 192–197 (2019).

    Article  CAS  Google Scholar 

  30. Lee, W. et al. Ultralow thermal conductivity in all-inorganic halide perovskites. Proc. Natl Acad. Sci. USA 114, 8693–8697 (2017).

    Article  CAS  Google Scholar 

  31. Maes, J. et al. Light absorption coefficient of CsPbBr3 perovskite nanocrystals. J. Phys. Chem. Lett. 9, 3093–3097 (2018).

    Article  CAS  Google Scholar 

  32. de Mello, J. C., Wittmann, H. F. & Friend, R. H. An improved experimental determination of external photoluminescence quantum efficiency. Adv. Mater. 9, 230–232 (1997).

    Article  Google Scholar 

  33. Ilavsky, J. Nika: software for two-dimensional data reduction. J. Appl. Crystallogr. 45, 324–328 (2012).

    Article  CAS  Google Scholar 

  34. Jiang, Z. GIXSGUI: a MATLAB toolbox for grazing-incidence X-ray scattering data visualization and reduction, and indexing of buried three-dimensional periodic nanostructured films. J. Appl. Crystallogr. 48, 917–926 (2015).

    Article  CAS  Google Scholar 

  35. Proppe, A. H. et al. Picosecond charge transfer and long carrier diffusion lengths in colloidal quantum dot solids. Nano Lett. 18, 7052–7059 (2018).

    Article  CAS  Google Scholar 

  36. Cademartiri, L. et al. Size-dependent extinction coefficients of PbS quantum dots. J. Am. Chem. Soc. 128, 10337–10346 (2006).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Ontario Research Fund–Research Excellence Program and the Natural Sciences and Engineering Research Council of Canada (NSERC, grant number 537463-18). M.I.S. acknowledges the support of the Banting Postdoctoral Fellowship Program, administered by the Government of Canada. We acknowledge financial support from the Natural Science Foundation of China (numbers 51821002 and 91733301) and the Collaborative Innovation Centre of Suzhou Nano Science and Technology. Y.-K.W. also acknowledges the financial support of the China Scholarship Council (number 201806920067). We thank Huawei Canada for their financial support. Z.-H.L. and all co-authors from the Department of Materials Science and Engineering at the University of Toronto acknowledge the financial support from the Natural Sciences and Engineering Research Council of Canada (NSERC, grant number 216956-12) and the National Natural Science Foundation of China (grant number 11774304).

Author information

Author notes

  1. Se-Woong Baek

    Present address: Department of Chemical and Biological Engineering, Korea University, Seoul, Korea

  2. Makhsud I. Saidaminov

    Present address: Department of Chemistry and Electrical and Computer Engineering, Centre for Advanced Materials and Related Technologies (CAMTEC), University of Victoria, Victoria, British Columbia, Canada

  3. These authors contributed equally: Yitong Dong, Ya-Kun Wang, Fanglong Yuan.

Authors and Affiliations

  1. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada

    Yitong Dong, Ya-Kun Wang, Fanglong Yuan, Andrew Johnston, Yuan Liu, Dongxin Ma, Min-Jae Choi, Bin Chen, Se-Woong Baek, Laxmi Kishore Sagar, James Fan, Yi Hou, Seungjin Lee, Bin Sun, Sjoerd Hoogland, Rafael Quintero-Bermudez, Hinako Ebe, Petar Todorovic, Makhsud I. Saidaminov & Edward H. Sargent

  2. Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, PR China

    Ya-Kun Wang & Liang-Sheng Liao

  3. Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada

    Fanglong Yuan, Peicheng Li, Hao Ting Kung & Zheng-Hong Lu

  4. Department of Chemistry, University of Toronto, Toronto, Ontario, Canada

    Mahshid Chekini & Eugenia Kumacheva

  5. Centre for Nanoanalysis and Electron Microscopy (CENEM) and Institute of Micro- and Nanostructure Research, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany

    Mingjian Wu & Erdmann Spiecker

  6. Department of Physical and Environmental Sciences, University of Toronto Scarborough, Scarborough, Ontario, Canada

    Filip Dinic & Oleksandr Voznyy

Authors
  1. Yitong Dong
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Ya-Kun Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Fanglong Yuan
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Andrew Johnston
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Yuan Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Dongxin Ma
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Min-Jae Choi
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Bin Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Mahshid Chekini
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Se-Woong Baek
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Laxmi Kishore Sagar
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. James Fan
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Yi Hou
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Mingjian Wu
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Seungjin Lee
    View author publications

    You can also search for this author in PubMed Google Scholar

  16. Bin Sun
    View author publications

    You can also search for this author in PubMed Google Scholar

  17. Sjoerd Hoogland
    View author publications

    You can also search for this author in PubMed Google Scholar

  18. Rafael Quintero-Bermudez
    View author publications

    You can also search for this author in PubMed Google Scholar

  19. Hinako Ebe
    View author publications

    You can also search for this author in PubMed Google Scholar

  20. Petar Todorovic
    View author publications

    You can also search for this author in PubMed Google Scholar

  21. Filip Dinic
    View author publications

    You can also search for this author in PubMed Google Scholar

  22. Peicheng Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  23. Hao Ting Kung
    View author publications

    You can also search for this author in PubMed Google Scholar

  24. Makhsud I. Saidaminov
    View author publications

    You can also search for this author in PubMed Google Scholar

  25. Eugenia Kumacheva
    View author publications

    You can also search for this author in PubMed Google Scholar

  26. Erdmann Spiecker
    View author publications

    You can also search for this author in PubMed Google Scholar

  27. Liang-Sheng Liao
    View author publications

    You can also search for this author in PubMed Google Scholar

  28. Oleksandr Voznyy
    View author publications

    You can also search for this author in PubMed Google Scholar

  29. Zheng-Hong Lu
    View author publications

    You can also search for this author in PubMed Google Scholar

  30. Edward H. Sargent
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

Y.D., Y.-K.W. and F.Y. conceived the study. Y.D. and Y.-K.W. synthesized the CsPbBr3 perovskite QDs and developed the ligand exchange method. Y.D. performed steady-state absorption and photoluminescence spectra measurements, time-correlated single-photon counting measurements and transient absorption spectroscopy measurements. Y.-K.W. and F.Y. fabricated the LED devices, performed XRD measurements and characterized the LEDs. B.C., S.-W.B. and M.W. performed TEM, SEM and STEM imaging. J.F. performed FTIR spectroscopy measurements. L.K.S. performed the TGA. M.-J.C. and M.C. performed the ζ-potential measurements. F.Y., P.L. and H.T.K. performed XPS measurements. R.Q.-B. and A.J. performed GISAXS measurements. Y.H., Y.L., B.S., S.L., D.M., P.T., F.D., H.E., E.K. and S.H. contributed to device fabrication and data analyses. Y.D. and O.V. performed the device simulation. M.I.S., Z.-H.L and E.H.S. supervised the project. All authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Zheng-Hong Lu or Edward H. Sargent.

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 Figs. 1–20, discussion, Tables 1–8 and refs. 1–15.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Dong, Y., Wang, YK., Yuan, F. et al. Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots. Nat. Nanotechnol. 15, 668–674 (2020). https://doi.org/10.1038/s41565-020-0714-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41565-020-0714-5

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