Photonics Research, Volume. 9, Issue 9, 1784(2021)

Suppressing surface plasmon losses to improve the efficiency of blue organic light-emitting diodes using the plasmonic quasi-bandgap phenomenon

Tae-Woo Lee, Dohong Kim, Jun Hee Han, Somin Lee, Hoseung Lee, Seungyeop Choi, and Kyung Cheol Choi*
Author Affiliations
  • School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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    Figures & Tables(12)
    Schematic of (a) symmetric and (b) asymmetric DMD waveguides.
    Dispersion relation of the (a), (b) symmetric and (c), (d) asymmetric waveguides. (a) and (c) are even plasmonic waveguide modes. (b) and (d) are odd plasmonic waveguide modes.
    Electric field profiles of waveguides using FDTD simulation. (a) Simulation structure, and mode profile of the (b) symmetric DMD waveguide and (c) asymmetric DMD waveguide.
    (a) Thickness of each layer, used to determine the microcavity in a thin Ag film DMD electrode; (b) spectral intensity of the capping layer thickness at 460 nm wavelength; spectral intensity according to wavelength at optimized (c) NPB and (d) ZnS capping layer thicknesses.
    Inverted top emission OLED structure. Schematic of (a) OLEDs with symmetric DMD electrode and (b) OLEDs with asymmetric DMD electrode; (c) and (d) their FIB-SEM images.
    Electrical and optical properties of the inverted top emission OLED devices with symmetric/asymmetric DMD electrodes. (a) Current density-voltage; (b) luminance-current density; (c) efficacy-current density; and (d) EL spectrum.
    (a) Calculated spectral power density at a wavelength of 460 nm for the symmetric and asymmetric DMD electrodes with respect to the normalized in-plane wave vector and (b) its spectral power density ratio; (c) total power ratio of both electrodes in a study considering the Purcell effect.
    Transparent OLED structure. Schematic of transparent OLED with (a) ITO anode and asymmetric DMD cathode, and (b) both asymmetric DMD electrodes; (c) luminous transmittance of (a), and (d) luminous transmittance of (b) with respect to the ZnS thickness; (e) measured transmittance of (a), and (f) measured transmittance of (b). Insets of (e) and (f) indicate photographs of the transparent OLED with on/off images.
    Electrical and optical properties of the transparent OLED devices with ITO/asymmetric DMD electrodes. (a) Current density-voltage; (b) luminance-current density; (c) efficacy-current density; (d) EQE-current density; (e) power efficiency-current density; and (f) normalized EL spectrum.
    (a) Calculated spectral power density at a wavelength of 460 nm for the ITO and asymmetric DMD electrodes with respect to the normalized in-plane wave vector; (b) total power ratio of both electrodes in an analysis considering the Purcell effect.
    Flexibility of proposed transparent OLED. (a) Sheet resistance ratio of each electrode with respect to number of bendings. Inset of (a) indicates bending strain. Photograph of flexible transparent OLED with (b) off and (c) on images.
    • Table 1. Summarizing Device Labels and Their Thicknesses

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      Table 1. Summarizing Device Labels and Their Thicknesses

      Microcavity SymmetricMicrocavity AsymmetricTransparent SymmetricTransparent Asymmetric
      MaterialsThicknessMaterialsThicknessMaterialsThicknessMaterialsThickness
      AL100 nmAl100 nmITO150 nmZns19 nm
      Liq1 nmLiq1 nmMoO35 nmAg8 nm
      Alq310 nmAlq310 nmNPB45 nmMoO35 nm
      MADN/DSA-ph25 nmMADN/DSA-ph25 nmMADN/DSA-ph25 nmNPB45 nm
      NPB45 nmNPB45 nmAlq310 nmMADN/DSA-ph25 nm
      MoO35 nmMoO35 nmCs2CO31 nmAlq310 nm
      Ag12 nmAg12 nmAg12 nmCs2CO31 nm
      NPB85 nmZnS70 nmZnS29 nmAg12 nm
       Zns24 nm
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    Tae-Woo Lee, Dohong Kim, Jun Hee Han, Somin Lee, Hoseung Lee, Seungyeop Choi, Kyung Cheol Choi, "Suppressing surface plasmon losses to improve the efficiency of blue organic light-emitting diodes using the plasmonic quasi-bandgap phenomenon," Photonics Res. 9, 1784 (2021)

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    Paper Information

    Category: Optoelectronics

    Received: Dec. 22, 2020

    Accepted: Jul. 7, 2021

    Published Online: Aug. 20, 2021

    The Author Email: Kyung Cheol Choi (kyungcc@kaist.ac.kr)

    DOI:10.1364/PRJ.418160

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