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High-performance crosslinked colloidal quantum-dot light-emitting diodes


Colloidal quantum-dot light-emitting diodes have recently received considerable attention due to their ease of colour tunability, high brightness and narrow emission bandwidth. Although there have been rapid advances in luminance, efficiency and lifetime, device performance is still limited by the large energy barriers for hole and electron injection into the quantum-dot layer. Here, we show that by crosslinking the colloidal quantum-dot layer, the charge injection barrier in a red-light-emitting quantum-dot light-emitting diode may be considerably reduced by using a sol–gel TiO2 layer for electron transport. The device architecture is compatible with all-solution device fabrication and the resulting device shows a high luminance (12,380 cd m−2), low turn-on voltage (1.9 V) and high power efficiency (2.41 lm W−1). Incorporation of the technology into a display device with an active matrix drive backplane suggests that the approach has promise for use in high-performance, easy-to-fabricate, large-area displays and illumination sources.

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Figure 1: Structure and energy levels of the QD-LED.
Figure 2: Current density versus voltage characteristics of the QD-LED.
Figure 3: Performance and JV characteristics for QD-LEDs with different PEDOT:PSS conductivities.
Figure 4: Electroluminescence performance of QD-LEDs.
Figure 5: Efficiency and electroluminescence image of QD-LEDs.


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The authors thank J. Lee, J. M. Lee, J. Chung and I. Song for helpful discussion, S. Jun and H. Jang for providing quantum dots and J. W. Kim, Y. T. Chun, J.-Y. Kwon and Y. G. Lee for fabricating the QD–LED device with the a-Si TFT backplane.

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K.-S.C., E.K.L., W.-J.J. and B.L.C. carried out the experiment and contributed to the writing of the paper. E.J. synthesized the quantum dots. T.-H.K., S.J.L., S.-J.K., J.Y.H. and B.-K.K. assisted with the experiment and the device analysis. J.M.K. contributed to the writing of the paper and the project planning.

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Correspondence to Byoung Lyong Choi.

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Cho, KS., Lee, E., Joo, WJ. et al. High-performance crosslinked colloidal quantum-dot light-emitting diodes. Nature Photon 3, 341–345 (2009).

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