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Electroluminescence from single monolayers of nanocrystals in molecular organic devices


The integration of organic and inorganic materials at the nanometre scale into hybrid optoelectronic structures enables active devices1,2,3 that combine the diversity of organic materials with the high-performance electronic and optical properties of inorganic nanocrystals4. The optimization of such hybrid devices ultimately depends upon the precise positioning of the functionally distinct materials. Previous studies5,6 have already emphasized that this is a challenge, owing to the lack of well-developed nanometre-scale fabrication techniques. Here we demonstrate a hybrid light-emitting diode (LED) that combines the ease of processability of organic materials with the narrow-band, efficient luminescence of colloidal quantum dots7 (QDs). To isolate the luminescence processes from charge conduction, we fabricate a quantum-dot LED (QD-LED) that contains only a single monolayer of QDs, sandwiched between two organic thin films. This is achieved by a method that uses material phase segregation between the QD aliphatic capping groups and the aromatic organic materials. In our devices, where QDs function exclusively as lumophores, we observe a 25-fold improvement in luminescence efficiency (1.6 cd A-1 at 2,000 cd m-2) over the best previous QD-LED results5. The reproducibility and precision of our phase-segregation approach suggests that this technique could be widely applicable to the fabrication of other hybrid organic/inorganic devices.

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Figure 1: Electroluminescence spectra and structures for two QD-LEDs, devices I and II.
Figure 2: AFM images showing the surface morphology of various organic/QD films.
Figure 3: External quantum efficiency versus current density for the two devices shown in Fig. 1.
Figure 4: Proposed energy level diagram of device I.


  1. Kagan, C. R., Mitzi, D. B. & Dimitrakopoulos, C. D. Organic-inorganic hybrid materials as semiconducting channels in thin-film field-effect transistors. Science 286, 945–947 (1999)

    CAS  Article  Google Scholar 

  2. Huynh, W. U., Dittmer, J. J. & Alivisatos, A. P. Hybrid nanorod-polymer solar cells. Science 295, 2425–2427 (2002)

    ADS  CAS  Article  Google Scholar 

  3. Colvin, V., Schlamp, M. & Alivisatos, A. Light-emitting diodes made from cadmium selenide nanocrystals and a semiconducting polymer. Nature 370, 354–357 (1994)

    ADS  CAS  Article  Google Scholar 

  4. Murray, C. B., Norris, D. J. & Bawendi, M. G. Synthesis and characterization of nearly monodisperse CdE (E = S, Se, Te) semiconductor nanocrystallites. J. Am. Chem. Soc. 115, 8706–8715 (1993)

    CAS  Article  Google Scholar 

  5. Schlamp, M. C., Peng, X. G. & Alivisatos, A. P. Improved efficiencies in light emitting diodes made with CdSe(CdS) core/shell type nanocrystals and a semiconducting polymer. J. Appl. Phys. 82, 5837–5842 (1997)

    ADS  CAS  Article  Google Scholar 

  6. Dabbousi, B. O., Bawendi, M. G., Onitsuka, O. & Rubner, M. F. Electroluminescence from CdSe quantum-dot/polymer composites. Appl. Phys. Lett. 66, 1316–1318 (1995)

    ADS  CAS  Article  Google Scholar 

  7. Dabbousi, B. O. et al. (CdSe)ZnS core-shell quantum dots: Synthesis and characterization of a size series of highly luminescent nanocrystallites. J. Phys. Chem. B 101, 9463–9475 (1997)

    CAS  Article  Google Scholar 

  8. Hines, M. A. & Guyot-Sionnest, P. Synthesis and characterization of strongly luminescing ZnS-capped CdSe nanocrystals. J. Phys. Chem. 100, 468–471 (1996)

    CAS  Article  Google Scholar 

  9. Adachi, C. et al. Nearly 100% internal phosphorescence efficiency in an organic light-emitting device. J. Appl. Phys. 90, 5048–5051 (2001)

    ADS  CAS  Article  Google Scholar 

  10. Moller, S. & Forrest, S. R. Improved light out-coupling in organic light emitting diodes employing ordered microlens arrays. J. Appl. Phys. 91, 3324–3327 (2002)

    ADS  CAS  Article  Google Scholar 

  11. Dirr, S., Bohler, A., Wiese, S., Johannes, H. H. & Kowalsky, W. Organic light emitting diodes with reduced spectral and spacial halfwidths. Jpn J. Appl. Phys.1 37, 1457–1461 (1998)

    CAS  Article  Google Scholar 

  12. Mattoussi, H. et al. Electroluminescence from heterostructures of poly(phenylene vinylene) and inorganic CdSe nanocrystals. J. Appl. Phys. 83, 7965–7974 (1998)

    ADS  CAS  Article  Google Scholar 

  13. Leatherdale, C. A. et al. Photoconductivity in CdSe quantum dot solids. Phys. Rev. B 62, 2669–2680 (2000)

    ADS  CAS  Article  Google Scholar 

  14. Era, M., Adachi, C., Tsutsui, T. & Saito, S. Double-heterostructure electroluminescent device with cyanine-dye bimolecular layer as an emitter. Chem. Phys. Lett. 178, 488–490 (1991)

    ADS  CAS  Article  Google Scholar 

  15. Morgan, N. Y. et al. Electronic transport in films of colloidal CdSe nanocrystals. Phys. Rev. B 66, 075339 (2002)

    ADS  Article  Google Scholar 

  16. Liu, J., Shi, Y. J. & Yang, Y. Improving the performance of polymer light-emitting diodes using polymer solid solutions. Appl. Phys. Lett. 79, 578–580 (2001)

    ADS  CAS  Article  Google Scholar 

  17. Kwong, R. C. et al. Efficient, saturated red organic light emitting devices based on phosphorescent platinum(II) porphyrins. Chem. Mater. 11, 3709–3713 (1999)

    CAS  Article  Google Scholar 

  18. Tamarat, P., Maali, A., Lounis, B. & Orrit, M. Ten years of single-molecule spectroscopy. J. Phys. Chem. A 104, 1–16 (2000)

    CAS  Article  Google Scholar 

  19. Empedocles, S. A., Norris, D. J. & Bawendi, M. G. Photoluminescence spectroscopy of single CdSe nanocrystallite quantum dots. Phys. Rev. Lett. 77, 3873–3876 (1996)

    ADS  CAS  Article  Google Scholar 

  20. Murray, C. B., Kagan, C. R. & Bawendi, M. G. Synthesis and characterization of monodisperse nanocrystals and close-packed nanocrystal assemblies. Annu. Rev. Mater. Sci. 30, 545–610 (2000)

    ADS  CAS  Article  Google Scholar 

  21. Hill, I. G. & Kahn, A. Organic semiconductor heterointerfaces containing bathocuproine. J. Appl. Phys. 86, 4515–4519 (1999)

    ADS  CAS  Article  Google Scholar 

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We thank D. Mascaro and E. Shaw for assistance in acquiring AFM images. This work was supported in part by the NSF-MRSEC programme, DMR, and Universal Display Corporation; it made use of MRSEC shared facilities supported by the National Science Foundation.

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Correspondence to Vladimir Bulović.

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Coe, S., Woo, WK., Bawendi, M. et al. Electroluminescence from single monolayers of nanocrystals in molecular organic devices. Nature 420, 800–803 (2002).

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