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Colloidal quantum-dot light-emitting diodes with metal-oxide charge transport layers

Nature Photonics volume 2, pages 247–250 (2008)Cite this article

Abstract

Colloidal quantum dots, with their tunable luminescence properties, are uniquely suited for use as lumophores in light-emitting devices for display technologies and large-area planar lighting1,2,3,4,5,6,7,8,9,10. In contrast to epitaxially grown quantum dots, colloidal quantum dots can be synthesized as highly monodisperse colloids and solution deposited over large areas into densely packed, solid-state multilayers, which have shown promise as efficient optical gain media11. To be a viable platform for colour-tunable electrically pumped lasers, the present-generation quantum-dot LEDs must be modified to withstand the extended, high-current-density operation needed to achieve population inversion. This requirement necessitates a quantum-dot LED design that incorporates robust charge transport layers. Here we report the use of sputtered, amorphous inorganic semiconductors as robust charge transport layers and demonstrate devices capable of operating at current densities exceeding 3.5 A cm−2 with peak brightness of 1,950 Cd m−2 and maximum external electroluminescence efficiency of nearly 0.1%, which represents a 100-fold improvement over previously reported structures8,10.

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Figure 1: Quantum-dot light-emitting diode design.
Figure 2: Effect of ZnO:SnO2 layer deposition.
Figure 3: Quantum-dot light-emitting diode current–voltage characteristics.
Figure 4: Quantum-dot light-emitting diode EL spectrum and efficiency.
Figure 5: Quantum-dot light-emitting diode RC time-constant measurement.

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Acknowledgements

The authors would like to thank G. Nair and G. Chen for their technical assistance and P. Mardilovich for insightful discussions. This work was supported in part by the National Science Foundation Materials Research Science and Engineering Center at (NSF-MRSEC) the Massachusetts Institute of Technology (MIT) Program (DMR-0213282), making use of its Shared Experimental Facilities, the Harrison Spectroscopy Laboratory (NSF-CHE-011370), the U.S. Army through the Institute for Soldier Nanotechnologies (DAAD-19-02-0002), National Science Foundation Nanoscale Interdisciplinary Research Team (NSF NIRT) (CHE-0507147), and a Presidential Early Carrier Award for Scientists and Engineers (PECASE).

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Authors and Affiliations

  1. Department of Chemistry, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA

    J. M. Caruge, J. E. Halpert & M. G. Bawendi

  2. Department of Electrical Engineering, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA

    V. Wood & V. Bulović

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  1. J. M. Caruge
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  2. J. E. Halpert
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  3. V. Wood
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  4. V. Bulović
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  5. M. G. Bawendi
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J. M. Caruge, J. E. Halpert and V. Wood contributed equally to this work.

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Correspondence to J. M. Caruge, J. E. Halpert, V. Wood or V. Bulović.

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Caruge, J., Halpert, J., Wood, V. et al. Colloidal quantum-dot light-emitting diodes with metal-oxide charge transport layers. Nature Photon 2, 247–250 (2008). https://doi.org/10.1038/nphoton.2008.34

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