Highly efficient quantum dot near-infrared light-emitting diodes

Journal name:
Nature Photonics
Volume:
10,
Pages:
253–257
Year published:
DOI:
doi:10.1038/nphoton.2016.11
Received
Accepted
Published online
Corrected online

Colloidal quantum dots (CQDs) are emerging as promising materials for constructing infrared sources in view of their tunable luminescence, high quantum efficiency and compatibility with solution processing1. However, CQD films available today suffer from a compromise between luminescence efficiency and charge transport, and this leads to unacceptably high power consumption. Here, we overcome this issue by embedding CQDs in a high-mobility hybrid perovskite matrix. The new composite enhances radiative recombination in the dots by preventing transport-assisted trapping losses; yet does so without increasing the turn-on voltage. Through compositional engineering of the mixed halide matrix, we achieve a record electroluminescence power conversion efficiency of 4.9%. This surpasses the performance of previously reported CQD near-infrared devices two-fold, indicating great potential for this hybrid QD-in-perovskite approach.

At a glance

Figures

  1. QD-in-perovskite LED device architecture.
    Figure 1: QD-in-perovskite LED device architecture.

    a, Illustration of enhanced electroluminescence efficiency in PbS QDs in MAPbX3 (X = I, Br) perovskite CQD LEDs, the left panel illustrates that radiative recombination dominates when QDs and perovskite are lattice matched, whereas lattice mismatch causes interfacial defects (black dash line) and non-radiative recombination through traps (right panel). b, The corresponding spatial band diagram shows the mechanism of carrier transport, injection and recombination, illustrating the key parameters that are essential for highly efficient QD LEDs. c, HRTEM images of a PbS QD in a perovskite matrix (left), the LED device architecture used in this study (middle) and the corresponding cross-section SEM image of same device (right).

  2. Device performance and photoluminescent properties of CQDs in MAPbIxBr3–x perovskite.
    Figure 2: Device performance and photoluminescent properties of CQDs in MAPbIxBr3–x perovskite.

    a, EQE–current density performance of CQDs in mixed halide perovskite LEDs with various iodine molar concentrations. b, Normalized diffusion length of the mixed halide perovskite. c, PLQE of PbS QDs in MAPbIxBr3–x. d, ηtot at different radiative recombination rates (Rrad) with different defect densities (Nt) of the active layer.

  3. EL performance of QD-in-perovskite LEDs emitting at 1,391 nm.
    Figure 3: EL performance of QD-in-perovskite LEDs emitting at 1,391 nm.

    a, EL spectra (applied voltage, 2 V). b, EQE–current density performance. c, Current density–voltage curves. d, Radiance–voltage characteristics. Inset: Zoom-in region of radiance–voltage plots (0.9–1.3 V) showing device turn-on voltages. e, PCE–voltage performance for champion CQD-in-perovskite devices (3.6% volume ratio) matrix versus a pure CQD device. f, PCE–radiance performance of champion device compared with the current published record8 (solid star, radiance under PCE maximum; empty star, PCE under radiance maximum in the reference). Inset: Zoom-in region of radiance–PCE plot.

  4. Size tunability of CQDs in NIR LEDs.
    Figure 4: Size tunability of CQDs in NIR LEDs.

    a,b, Average peak EQE (a) and PCE (b) values of QD-in-perovskite devices with various CQD:perovskite volume ratios and device emission wavelengths. Error bars represent the standard deviation of several devices.

Change history

Corrected online 26 February 2016
In the version of this Letter originally published online, in Fig. 4a, the label on the y axis was incorrect. This error has been corrected in all versions of the Letter.

References

  1. Bourdakos, K. N., Dissanayake, D. M. N. M., Lutz, T., Silva, S. R. P. & Curry, R. J. Highly efficient near-infrared hybrid organic-inorganic nanocrystal electroluminescence device. Appl. Phys. Lett. 92, 9093 (2008).
  2. Sun, L. et al. Bright infrared quantum-dot light-emitting diodes through inter-dot spacing control. Nature Nanotech. 7, 369373 (2012).
  3. Medintz, I. L., Uyeda, H. T., Goldman, E. R. & Mattoussi, H. Quantum dot bioconjugates for imaging, labelling and sensing. Nature Mater. 4, 435446 (2005).
  4. Sargent, E. H. Infrared quantum dots. Adv. Mater. 17, 515522 (2005).
  5. Kim, K.-H. et al. Phosphorescent dye-based supramolecules for high-efficiency organic light-emitting diodes. Nature Commun. 5, 4769 (2014).
  6. Sekine, C., Tsubata, Y., Yamada, T., Kitano, M. & Doi, S. Recent progress of high performance polymer OLED and OPV materials for organic printed electronics. Sci. Technol. Adv. Mater. 15, 034203 (2014).
  7. Shirasaki, Y., Supran, G. J., Bawendi, M. G. & Bulović, V. Emergence of colloidal quantum-dot light-emitting technologies. Nature Photon. 7, 1323 (2013).
  8. Supran, G. J. et al. High-performance shortwave-infrared light-emitting devices using core–shell (PbS–CdS) colloidal quantum dots. Adv. Mater. 27, 14371442 (2015).
  9. Tessler, N., Medvedev, V., Kazes, M., Kan, S. & Banin, U. Efficient near-infrared polymer nanocrystal light-emitting diodes. Science 295, 15061508 (2002).
  10. Zhitomirsky, D., Voznyy, O., Hoogland, S. & Sargent, E. H. Measuring charge carrier diffusion in coupled colloidal quantum dot solids. ACS Nano 7, 52825290 (2013).
  11. Choi, J. J. et al. Photogenerated exciton dissociation in highly coupled lead salt nanocrystal assemblies. Nano Lett. 10, 18051811 (2010).
  12. Moroz, P. et al. Infrared emitting PbS nanocrystal solids through matrix encapsulation. Chem. Mater. 26, 42564264 (2014).
  13. Greenham, N., Peng, X. & Alivisatos, A. Charge separation and transport in conjugated-polymer/semiconductor-nanocrystal composites studied by photoluminescence quenching and photoconductivity. Phys. Rev. B 54, 1762817637 (1996).
  14. Steckel, J. S., Coe-Sullivan, S., Bulović, V. & Bawendi, M. G. 1.3 μm to 1.55 μm tunable electroluminescence from PbSe quantum dots embedded within an organic device. Adv. Mater. 15, 18621866 (2003).
  15. Ning, Z. et al. Quantum-dot-in-perovskite solids. Nature 523, 324328 (2015).
  16. Hu, L. et al. PbS colloidal quantum dots as an effective hole transporter for planar heterojunction perovskite solar cells. J. Mater. Chem. A 3, 515518 (2015).
  17. Jeon, N. J. et al. Compositional engineering of perovskite materials for high-performance solar cells. Nature 517, 476480 (2015).
  18. Shi, D. et al. Low trap-state density and long carrier diffusion in organolead trihalide perovskite single crystals. Science 347, 519522 (2015).
  19. Hines, M. A. & Scholes, G. D. Colloidal PbS nanocrystals with size-tunable near-infrared emission: observation of post-synthesis self-narrowing of the particle size distribution. Adv. Mater. 15, 18441849 (2003).
  20. De Mello, J. C., Wittmannn, H. F. & Friend, R. H. An improved experimental determination of external photoluminescence quantum efficiency. Adv. Mater. 9, 230 (1997).
  21. Xing, G. et al. Long-range balanced electron- and hole-transport lengths in organic-inorganic CH3NH3PbI3. Science 342, 344347 (2013).
  22. Burgelman, M., Nollet, P. & Degrave, S. Modelling polycrystalline semiconductor solar cells. Thin Solid Films 527, 361362 (2000).
  23. Zhitomirsky, D. et al. Engineering colloidal quantum dot solids within and beyond the mobility-invariant regime. Nature Commun. 5, 3803 (2014).

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Author information

  1. Present address: School of Physical Science and Technology, ShanghaiTech University, Haike Road 100, 201210 Shanghai, China

    • Zhijun Ning
  2. These authors contributed equally to this work

    • Xiwen Gong &
    • Zhenyu Yang

Affiliations

  1. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada

    • Xiwen Gong,
    • Zhenyu Yang,
    • Grant Walters,
    • Riccardo Comin,
    • Zhijun Ning,
    • Eric Beauregard,
    • Valerio Adinolfi,
    • Oleksandr Voznyy &
    • Edward H. Sargent

Contributions

X.G., Z.Y., Z.N., and E.H.S. designed and directed this study. X.G. and Z.Y. contributed to all the experimental work. G.W. and E.B. carried out the PLQE measurements and analysis. R.C. performed PL decay measurement and analysis. V.A., O.V. and X.G. performed optoelectronic simulation. X.G., Z.Y., R.C., and E.H.S. wrote the manuscript.

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The authors declare no competing financial interests.

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