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Enhanced light extraction from organic light-emitting devices using a sub-anode grid

Nature Photonics volume 9, pages 758763 (2015) | Download Citation

Abstract

We demonstrate the highly effective extraction of waveguided light from the active region of organic light-emitting devices using a non-diffractive dielectric grid layer placed between the transparent anode and the substrate. The sub-anode grid couples out all waveguide mode power into the substrate without changing the device electrical properties, resulting in an increase in both the external quantum efficiency and luminous efficacy for green phosphorescent organic light-emitting devices from 15 ± 1% and 36 ± 2 lm W–1 to 18 ± 1% and 43 ± 2 lm W–1. These characteristics are further increased to 40 ± 2% and 95 ± 4 lm W–1 when all glass modes are also extracted. The use of a thick electron transport layer further reduces surface plasmon modes, resulting in an increase in the substrate and air modes by 50 ± 8% compared with devices lacking the grids. The sub-anode grid has minimal impact on organic light-emitting device emission wavelength and viewing angle, and is likely to prove beneficial for a broad range of display and lighting applications.

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Acknowledgements

The authors thank K. Lee for discussions. The authors acknowledge financial support from Universal Display Corporation. This work was performed in part at the Lurie Nanofabrication Facility, a member of the National Nanotechnology Infrastructure Network, which is supported in part by the National Science Foundation.

Author information

Affiliations

  1. Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, USA

    • Yue Qu
    •  & Stephen R. Forrest
  2. Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA

    • Michael Slootsky
    •  & Stephen R. Forrest
  3. Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA

    • Stephen R. Forrest

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Contributions

Y.Q. performed simulations, fabrication of the PHOLEDs, measurements and data analysis. M.S. designed the sub-anode grid and performed simulations, fabrication and AFM image scans. S.R.F directed the research project and analysed results. All authors discussed the results and contributed to the manuscript.

Competing interests

One of the authors (S.R.F.) has a small equity interest in one of the sponsors of this research (Universal Display Corporation).

Corresponding author

Correspondence to Stephen R. Forrest.

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DOI

https://doi.org/10.1038/nphoton.2015.194