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Extremely efficient flexible organic light-emitting diodes with modified graphene anode


Although graphene films have a strong potential to replace indium tin oxide anodes in organic light-emitting diodes (OLEDs), to date, the luminous efficiency of OLEDs with graphene anodes has been limited by a lack of efficient methods to improve the low work function and reduce the sheet resistance of graphene films to the levels required for electrodes1,2,3,4. Here, we fabricate flexible OLEDs by modifying the graphene anode to have a high work function and low sheet resistance, and thus achieve extremely high luminous efficiencies (37.2 lm W–1 in fluorescent OLEDs, 102.7 lm W–1 in phosphorescent OLEDs), which are significantly higher than those of optimized devices with an indium tin oxide anode (24.1 lm W–1 in fluorescent OLEDs, 85.6 lm W–1 in phosphorescent OLEDs). We also fabricate flexible white OLED lighting devices using the graphene anode. These results demonstrate the great potential of graphene anodes for use in a wide variety of high-performance flexible organic optoelectronics.

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Figure 1: Schematic illustrations of hole injection from graphene, device structure and fabrication steps for flexible OLEDs.
Figure 2: Performance of green OLEDs with graphene, carbon nanotube and ITO anodes.
Figure 3: Device structure and performance of white OLEDs with a graphene anode, and the flexible OLED lighting device.
Figure 4: DI SCLC transient current and hole-injection efficiency of graphene anodes and ITO anode.


  1. Bonaccorso, F., Sun, Z., Hasan, T. & Ferrari, A. C. Graphene photonics and optoelectronics. Nature Photon. 4, 611–622 (2010).

    Article  ADS  Google Scholar 

  2. Rogers, J. A. Electronic materials: making graphene for macroelectronics. Nature Nanotech. 3, 254–255 (2008).

    Article  ADS  Google Scholar 

  3. Wu, J. et al. Organic light-emitting diodes on solution-processed graphene transparent electrodes. ACS Nano 4, 43–48 (2010).

    Article  Google Scholar 

  4. Sun, T. et al. Multilayered graphene used as anode of organic light emitting devices. Appl. Phys. Lett. 96, 133301 (2010).

    Article  ADS  Google Scholar 

  5. Novoselov, K. S. et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).

    Article  ADS  Google Scholar 

  6. Geim, A. K. & Novoselov, K. S. The rise of graphene. Nature Mater. 6, 183–191 (2007).

    Article  ADS  Google Scholar 

  7. Zhang, Y., Tan, Y., Stormer, H. L. & Kim, P. Experimental observation of the quantum Hall effect and Berry's phase in graphene. Nature 438, 201–205 (2005).

    Article  ADS  Google Scholar 

  8. Kim, K. S. et al. Large-scale pattern growth of graphene films for stretchable transparent electrodes. Nature 457, 706–710 (2009).

    Article  ADS  Google Scholar 

  9. Lee, Y. et al. Wafer-scale synthesis and transfer of graphene films. Nano. Lett. 10, 490–493 (2010).

    Article  ADS  Google Scholar 

  10. Bae, S. et al. Roll-to-roll production of 30-inch graphene films for transparent electrodes. Nature Nanotech. 5, 574–578 (2010).

    Article  ADS  Google Scholar 

  11. Li, X. et al. Large-area synthesis of high-quality and uniform graphene films on copper foils. Science 324, 1312–1314 (2009).

    Article  ADS  Google Scholar 

  12. Reina, A. et al. Layer area, few-layer graphene films on arbitrary substrates by chemical vapor deposition. Nano Lett. 9, 30–35 (2009).

    Article  ADS  Google Scholar 

  13. Eda, G., Fanchini, G. & Chhowalla, M. Large-area ultrathin films of reduced graphene oxide as a transparent and flexible electronic material. Nature Nanotech. 3, 270–274 (2008).

    Article  Google Scholar 

  14. Matyba, P. et al. Graphene and mobile ions: the key to all-plastic, solution-processed light-emitting devices. ACS Nano 4, 637–642 (2010).

    Article  Google Scholar 

  15. Arco, L. G. D. et al. Continuous, highly flexible, and transparent graphene films by chemical vapor deposition for organic photovoltaics. ACS Nano 4, 2865–2873 (2010).

    Article  Google Scholar 

  16. Yin, Z. et al. Organic photovoltaic devices using highly flexible reduced graphene oxide films as transparent electrodes. ACS Nano 4, 5263–5268 (2010).

    Article  Google Scholar 

  17. Wu, J. et al. Organic solar cells with solution-processed graphene transparent electrodes. Appl. Phys. Lett. 92, 263302 (2008).

    Article  ADS  Google Scholar 

  18. Choe, M. et al. Efficient bulk-heterojunction photovoltaic cells with transparent multi-layer graphene electrodes. Org. Electron. 11, 1864–1869 (2010).

    Article  Google Scholar 

  19. Wang, X., Zhi, L. & Müllen, K. Transparent, conductive graphene electrodes for dye-sensitized solar cells. Nano Lett. 8, 323–327 (2008).

    Article  ADS  Google Scholar 

  20. Kumar, A. & Zhou, C. The race to replace tin-doped indium oxide: which material will win? ACS Nano 4, 11–14 (2010).

    Article  Google Scholar 

  21. Choi, M-R. et al. Soluble self-doped conducting polymer compositions with tunable work function as hole injection/extraction layers in organic optoelectronics. Angew. Chem. Int. Ed. 50, 6274–6277 (2011).

    Article  Google Scholar 

  22. Li, J. et al. Organic light-emitting diodes having carbon nanotube anodes. Nano Lett. 6, 2472–2477 (2006).

    Article  ADS  Google Scholar 

  23. Chien, Y-M., Lefevre, F., Shin, I. & Izquierdo, R. A solution processed top emission OLED with transparent carbon nanotube electrodes. Nanotechnology 21, 134020 (2010).

    Article  ADS  Google Scholar 

  24. Helender, M. G. et al. Chlorinated indium tin oxide electrodes with high work function for organic device compatibility. Science 332, 944–947 (2011).

    Article  ADS  Google Scholar 

  25. Poplavskyy, D., Su, W. & So, F. Bipolar charge transport, injection, and trapping studies in a model green-emitting polyfluorene copolymer. J. Appl. Phys. 98, 014501 (2005).

    Article  ADS  Google Scholar 

  26. Campbell, A. J., Bradley, D. D. C. & Antoniadisc, H. Quantifying the efficiency of electrodes for positive carrier injection into poly(9,9-dioctylfluorene) and representative copolymers. J. Appl. Phys. 89, 3343–3351 (2001).

    Article  ADS  Google Scholar 

  27. Cheung, C. H., Kwok, K. C., Tse, S. C. & So, S. K. Determination of carrier mobility in phenylamine by time-of-flight, dark-injection, and thin film transistor techniques. J. Appl. Phys. 103, 093705 (2008).

    Article  ADS  Google Scholar 

  28. Harding, M. J., Poplavskyy, D., Choong, V-E., So, F. & Campbell, A. J. Variations in hole injection due to fast and slow interfacial traps in polymer light-emitting diodes with interlayers. Adv. Funct. Mater. 20, 119–130 (2010).

    Article  Google Scholar 

  29. Jong, M. P. D., IJzendoorn, L. J. V. & Voigt, M. J. A. D. Stability of the interface between indium-tin-oxide and poly (3,4-ethylenedioxythiophene)/poly(styrenesulfonate) in polymer light-emitting diodes. Appl. Phys. Lett. 77, 2255–2257 (2000).

    Article  ADS  Google Scholar 

  30. Sekitani, T. et al. Stretchable active-matrix organic light-emitting diode display using printable elastic conductors. Nature Mater. 8, 494–499 (2009).

    Article  ADS  Google Scholar 

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This research was supported by the Basic Research Program and Global Frontier Research Center for Advanced Soft Electronics through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (nos. 2009-0067533, 2009-0075025, 2011-0006268 and 2009-0090177). This research was also supported by the Converging Research Center Program through the Ministry of Education, Science and Technology (no. 2010K001431).

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Authors and Affiliations



T.-H.H. designed and conducted most of the experiments, analysed the data and prepared the manuscript. Y.L. and S.-H.B. conducted experiments regarding graphene growth, patterning of graphene anodes and characterization. S.-H.W. and M.-R.C. helped with the OLED fabrication experiments. B.H.H. interpreted data and suggested improvements to the manuscript. J.-H.A. designed the graphene experiments, analysed data and prepared the manuscript. T.-W.L. initiated the study, designed all the experiments, analysed the data and prepared the manuscript. All authors discussed the results and contributed to the paper.

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Correspondence to Jong-Hyun Ahn or Tae-Woo Lee.

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The authors declare no competing financial interests.

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Han, TH., Lee, Y., Choi, MR. et al. Extremely efficient flexible organic light-emitting diodes with modified graphene anode. Nature Photon 6, 105–110 (2012).

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