Abstract

The efficiency of organic light-emitting diodes (OLEDs) is still limited by poor light outcoupling. In particular, the excitation of surface plasmon polaritons (SPPs) at metal-organic interfaces represents a major loss channel. By combining optical simulations and experiments on sim-plified luminescent thin-film structures we elaborate the conditions for the extraction of SPPs via coupling to high-index media. As a proof-of-concept, we demonstrate the possibility to extract light from wave-guided modes and surface plasmons in a top-emitting white OLED by a high-index prism.

© 2011 OSA

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References

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  1. S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” Appl. Phys.104, 123109 (2008).
    [CrossRef]
  2. L. H. Smith, J. A. E. Wasey, and W. L. Barnes, “Light outcoupling efficiency of top-emitting organic light-emitting diodes,” Appl. Phys. Lett.84, 2986 (2004).
    [CrossRef]
  3. J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
    [CrossRef]
  4. S. Wedge, I. R. Hooper, I. Sage, and W. L. Barnes, “Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons,” Phys. Rev. B69, 245418 (2004).
    [CrossRef]
  5. J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12, 809 (2011).
    [CrossRef]
  6. L. Smith and W. Barnes, “Using a low-index host layer to increase emission from organic light-emitting diode structures,” Org. Electron.7, 490 (2006).
    [CrossRef]
  7. T. Nakamura, N. Tsutsumi, N. Juni, and H. Fujii, “Thin-film waveguiding mode light extraction in organic elec-troluminescent device using high refractive index substrate,” Appl. Phys. Lett.97, 054505 (2005).
  8. G. Gaertner and H. Greiner, “Light extraction from oleds with (high) index matched glass substrates,” in “Organic Optoelectronics and Photonics III,”, E. A. M. Paul L. Heremans and Michele Muccini, ed. (SPIE, 2008), p. 69992T.
  9. S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
    [CrossRef]
  10. S. Mladenovski, K. Neyts, D. Pavicic, A. Werner, and C. Rothe, “Exceptionally efficient organic light emitting devices using high refractive index substrates,” Opt. Express17, 7562 (2009).
    [CrossRef] [PubMed]
  11. P. Andrew and W. L. Barnes, “Energy transfer across a metal film mediated by surface plasmon polaritons,” Science306, 1002 (2004).
    [CrossRef] [PubMed]
  12. S. A. Maier, Plasmonics: Fundamentals and Applications, 25th ed. (Springer, 2007).
  13. L. Novotny and B. Hecht, Principles of Nano-Optics, (Cambridge University Press, 2006).
  14. E. Kretschmann, “Die Bestimmung optischer Konstanten von Metallen durch Anregung von Oberflächenplasmaschwingungen,” Z. Physik241, 313 (1971).
    [CrossRef]
  15. G. Winter and W. L. Barnes, “Emission of light through thin silver films via near-field coupling to surface plasmon polaritons,” Appl. Phys. Lett.88, 051109 (2006).
    [CrossRef]
  16. W. L. Barnes, “Surface plasmon-polariton length scales: a route to sub-wavelength optics,” J. Opt. A, Pure Appl. Opt.8, S87 (2006).
    [CrossRef]

2011

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12, 809 (2011).
[CrossRef]

2009

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

S. Mladenovski, K. Neyts, D. Pavicic, A. Werner, and C. Rothe, “Exceptionally efficient organic light emitting devices using high refractive index substrates,” Opt. Express17, 7562 (2009).
[CrossRef] [PubMed]

2008

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” Appl. Phys.104, 123109 (2008).
[CrossRef]

2006

L. Smith and W. Barnes, “Using a low-index host layer to increase emission from organic light-emitting diode structures,” Org. Electron.7, 490 (2006).
[CrossRef]

G. Winter and W. L. Barnes, “Emission of light through thin silver films via near-field coupling to surface plasmon polaritons,” Appl. Phys. Lett.88, 051109 (2006).
[CrossRef]

W. L. Barnes, “Surface plasmon-polariton length scales: a route to sub-wavelength optics,” J. Opt. A, Pure Appl. Opt.8, S87 (2006).
[CrossRef]

2005

T. Nakamura, N. Tsutsumi, N. Juni, and H. Fujii, “Thin-film waveguiding mode light extraction in organic elec-troluminescent device using high refractive index substrate,” Appl. Phys. Lett.97, 054505 (2005).

2004

P. Andrew and W. L. Barnes, “Energy transfer across a metal film mediated by surface plasmon polaritons,” Science306, 1002 (2004).
[CrossRef] [PubMed]

L. H. Smith, J. A. E. Wasey, and W. L. Barnes, “Light outcoupling efficiency of top-emitting organic light-emitting diodes,” Appl. Phys. Lett.84, 2986 (2004).
[CrossRef]

S. Wedge, I. R. Hooper, I. Sage, and W. L. Barnes, “Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons,” Phys. Rev. B69, 245418 (2004).
[CrossRef]

1971

E. Kretschmann, “Die Bestimmung optischer Konstanten von Metallen durch Anregung von Oberflächenplasmaschwingungen,” Z. Physik241, 313 (1971).
[CrossRef]

Adachi, C.

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12, 809 (2011).
[CrossRef]

Andrew, P.

P. Andrew and W. L. Barnes, “Energy transfer across a metal film mediated by surface plasmon polaritons,” Science306, 1002 (2004).
[CrossRef] [PubMed]

Arndt, B. J.

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

Barnes, W.

L. Smith and W. Barnes, “Using a low-index host layer to increase emission from organic light-emitting diode structures,” Org. Electron.7, 490 (2006).
[CrossRef]

Barnes, W. L.

G. Winter and W. L. Barnes, “Emission of light through thin silver films via near-field coupling to surface plasmon polaritons,” Appl. Phys. Lett.88, 051109 (2006).
[CrossRef]

W. L. Barnes, “Surface plasmon-polariton length scales: a route to sub-wavelength optics,” J. Opt. A, Pure Appl. Opt.8, S87 (2006).
[CrossRef]

L. H. Smith, J. A. E. Wasey, and W. L. Barnes, “Light outcoupling efficiency of top-emitting organic light-emitting diodes,” Appl. Phys. Lett.84, 2986 (2004).
[CrossRef]

P. Andrew and W. L. Barnes, “Energy transfer across a metal film mediated by surface plasmon polaritons,” Science306, 1002 (2004).
[CrossRef] [PubMed]

S. Wedge, I. R. Hooper, I. Sage, and W. L. Barnes, “Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons,” Phys. Rev. B69, 245418 (2004).
[CrossRef]

Brütting, W.

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12, 809 (2011).
[CrossRef]

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” Appl. Phys.104, 123109 (2008).
[CrossRef]

Endo, A.

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12, 809 (2011).
[CrossRef]

Frischeisen, J.

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12, 809 (2011).
[CrossRef]

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” Appl. Phys.104, 123109 (2008).
[CrossRef]

Fujii, H.

T. Nakamura, N. Tsutsumi, N. Juni, and H. Fujii, “Thin-film waveguiding mode light extraction in organic elec-troluminescent device using high refractive index substrate,” Appl. Phys. Lett.97, 054505 (2005).

Gaertner, G.

G. Gaertner and H. Greiner, “Light extraction from oleds with (high) index matched glass substrates,” in “Organic Optoelectronics and Photonics III,”, E. A. M. Paul L. Heremans and Michele Muccini, ed. (SPIE, 2008), p. 69992T.

Gehlhaar, R.

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

Greiner, H.

G. Gaertner and H. Greiner, “Light extraction from oleds with (high) index matched glass substrates,” in “Organic Optoelectronics and Photonics III,”, E. A. M. Paul L. Heremans and Michele Muccini, ed. (SPIE, 2008), p. 69992T.

Hecht, B.

L. Novotny and B. Hecht, Principles of Nano-Optics, (Cambridge University Press, 2006).

Hooper, I. R.

S. Wedge, I. R. Hooper, I. Sage, and W. L. Barnes, “Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons,” Phys. Rev. B69, 245418 (2004).
[CrossRef]

Juni, N.

T. Nakamura, N. Tsutsumi, N. Juni, and H. Fujii, “Thin-film waveguiding mode light extraction in organic elec-troluminescent device using high refractive index substrate,” Appl. Phys. Lett.97, 054505 (2005).

Kretschmann, E.

E. Kretschmann, “Die Bestimmung optischer Konstanten von Metallen durch Anregung von Oberflächenplasmaschwingungen,” Z. Physik241, 313 (1971).
[CrossRef]

Krummacher, B. C.

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” Appl. Phys.104, 123109 (2008).
[CrossRef]

Leo, K.

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

Lindner, F.

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

Lüssem, B.

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

Maier, S. A.

S. A. Maier, Plasmonics: Fundamentals and Applications, 25th ed. (Springer, 2007).

Mladenovski, S.

Nakamura, T.

T. Nakamura, N. Tsutsumi, N. Juni, and H. Fujii, “Thin-film waveguiding mode light extraction in organic elec-troluminescent device using high refractive index substrate,” Appl. Phys. Lett.97, 054505 (2005).

Neyts, K.

Novotny, L.

L. Novotny and B. Hecht, Principles of Nano-Optics, (Cambridge University Press, 2006).

Nowy, S.

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” Appl. Phys.104, 123109 (2008).
[CrossRef]

Pavicic, D.

Reineke, S.

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

Reinke, N. A.

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” Appl. Phys.104, 123109 (2008).
[CrossRef]

Rothe, C.

Sage, I.

S. Wedge, I. R. Hooper, I. Sage, and W. L. Barnes, “Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons,” Phys. Rev. B69, 245418 (2004).
[CrossRef]

Schmidt, T. D.

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

Scholz, B. J.

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

Schwartz, G.

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

Seidler, N.

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

Smith, L.

L. Smith and W. Barnes, “Using a low-index host layer to increase emission from organic light-emitting diode structures,” Org. Electron.7, 490 (2006).
[CrossRef]

Smith, L. H.

L. H. Smith, J. A. E. Wasey, and W. L. Barnes, “Light outcoupling efficiency of top-emitting organic light-emitting diodes,” Appl. Phys. Lett.84, 2986 (2004).
[CrossRef]

Tsutsumi, N.

T. Nakamura, N. Tsutsumi, N. Juni, and H. Fujii, “Thin-film waveguiding mode light extraction in organic elec-troluminescent device using high refractive index substrate,” Appl. Phys. Lett.97, 054505 (2005).

Walzer, K.

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

Wasey, J. A. E.

L. H. Smith, J. A. E. Wasey, and W. L. Barnes, “Light outcoupling efficiency of top-emitting organic light-emitting diodes,” Appl. Phys. Lett.84, 2986 (2004).
[CrossRef]

Wedge, S.

S. Wedge, I. R. Hooper, I. Sage, and W. L. Barnes, “Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons,” Phys. Rev. B69, 245418 (2004).
[CrossRef]

Werner, A.

Winter, G.

G. Winter and W. L. Barnes, “Emission of light through thin silver films via near-field coupling to surface plasmon polaritons,” Appl. Phys. Lett.88, 051109 (2006).
[CrossRef]

Yokoyama, D.

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12, 809 (2011).
[CrossRef]

Appl. Phys.

S. Nowy, B. C. Krummacher, J. Frischeisen, N. A. Reinke, and W. Brütting, “Light extraction and optical loss mechanisms in organic light-emitting diodes: Influence of the emitter quantum efficiency,” Appl. Phys.104, 123109 (2008).
[CrossRef]

Appl. Phys. Lett.

L. H. Smith, J. A. E. Wasey, and W. L. Barnes, “Light outcoupling efficiency of top-emitting organic light-emitting diodes,” Appl. Phys. Lett.84, 2986 (2004).
[CrossRef]

T. Nakamura, N. Tsutsumi, N. Juni, and H. Fujii, “Thin-film waveguiding mode light extraction in organic elec-troluminescent device using high refractive index substrate,” Appl. Phys. Lett.97, 054505 (2005).

G. Winter and W. L. Barnes, “Emission of light through thin silver films via near-field coupling to surface plasmon polaritons,” Appl. Phys. Lett.88, 051109 (2006).
[CrossRef]

J. Opt. A, Pure Appl. Opt.

W. L. Barnes, “Surface plasmon-polariton length scales: a route to sub-wavelength optics,” J. Opt. A, Pure Appl. Opt.8, S87 (2006).
[CrossRef]

J. Photon. Energy

J. Frischeisen, B. J. Scholz, B. J. Arndt, T. D. Schmidt, R. Gehlhaar, C. Adachi, and W. Brütting, “Strategies for light extraction from surface plasmons in organic light-emitting diodes,” J. Photon. Energy1, 011004 (2011).
[CrossRef]

Nature (London)

S. Reineke, F. Lindner, G. Schwartz, N. Seidler, K. Walzer, B. Lüssem, and K. Leo, “White organic light-emitting diodes with fluorescent tube efficiency,” Nature (London)459, 234 (2009).
[CrossRef]

Opt. Express

Org. Electron.

J. Frischeisen, D. Yokoyama, A. Endo, C. Adachi, and W. Brütting, “Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emitters,” Org. Electron.12, 809 (2011).
[CrossRef]

L. Smith and W. Barnes, “Using a low-index host layer to increase emission from organic light-emitting diode structures,” Org. Electron.7, 490 (2006).
[CrossRef]

Phys. Rev. B

S. Wedge, I. R. Hooper, I. Sage, and W. L. Barnes, “Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons,” Phys. Rev. B69, 245418 (2004).
[CrossRef]

Science

P. Andrew and W. L. Barnes, “Energy transfer across a metal film mediated by surface plasmon polaritons,” Science306, 1002 (2004).
[CrossRef] [PubMed]

Z. Physik

E. Kretschmann, “Die Bestimmung optischer Konstanten von Metallen durch Anregung von Oberflächenplasmaschwingungen,” Z. Physik241, 313 (1971).
[CrossRef]

Other

S. A. Maier, Plasmonics: Fundamentals and Applications, 25th ed. (Springer, 2007).

L. Novotny and B. Hecht, Principles of Nano-Optics, (Cambridge University Press, 2006).

G. Gaertner and H. Greiner, “Light extraction from oleds with (high) index matched glass substrates,” in “Organic Optoelectronics and Photonics III,”, E. A. M. Paul L. Heremans and Michele Muccini, ed. (SPIE, 2008), p. 69992T.

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Figures (7)

Fig. 1
Fig. 1

Schematic illustration of an OLED with its optical loss channels: Emission to air is always present; emission to the substrate due to total internal reflection at the substrate-air-interface can be avoided by e.g. using a glass hemisphere with appropriate refractive index (cf. right part of the figure); WGMs within the organic layers and SPPs at the organic-metal-interface are hardly accessible, but account for up to 50% of energy losses.

Fig. 2
Fig. 2

(a) Kretschmann configuration: incident light with a fixed wavelength can fulfill the dispersion relation for SPP at a silver-air-interface at a specific angle. (b) Schematic SPP dispersion curve for a silver-air interface together with the light cones for far-field radiation on both sides of the metal layer. In an OLED, air as dielectric medium has to be replaced by an organic luminescent film with refractive index typically around 1.7 to 1.8. (c) Inversed Kretschmann configuration: by exciting dye molecules, SPPs at the organic-metal-interface can be excited via near-field coupling, which are then coupled out into an attached glass prism.

Fig. 3
Fig. 3

Stack layout and definition of the effective SPP index: (a), (b) For simplicity the emitter position is assumed at a distance of 5 nm from a semi-infinite silver layer and the distance to semi-infinite air is varied from 0 nm to 195 nm. The effective SPP index is determined by assuming a semi-infinite medium with a refractive index nSPP close to the silver layer so that the calculated analytical SPP dispersion (according to Eq. (1)) coincides with the numerically simulated one for a stack with finite Alq3 layer thickness. (c), (d) The same for a finite Ag thickness of 40 nm, where two SPP modes exist in the Ag film, one at each interface.

Fig. 4
Fig. 4

Experimental out-coupled p-polarized modes of stacks with different Alq3 thicknesses by using the inversed Kretschmann configuration (see Fig. 2(c)). (a) 40 nm Ag and 30 nm Alq3; the Alq3 thickness is thin enough so that the effective refractive index of the SPP is below the refractive index of the substrate and the SPP at the Ag-Alq3-interface can be coupled out. (b) 60 nm Ag and 210 nm Alq3; the first TM-mode (TM0) is coupled out. (c) 50 nm Ag and 460 nm Alq3; three modes (TM0-TM2) can be coupled out (the intensity within the rectangle from 65° to 90° and 650 nm to 800 nm was rescaled to make the TM0-mode more visible). The experiments were carried out by laser-excitation of the Alq3 (375 nm, 15 mW).

Fig. 5
Fig. 5

Simulated angular dispersion of the p-polarized modes for (a) BK7, (b) SF6 and (c) LiNbO3 prism attached to a 40 nm thick Ag layer and an Alq3 film with varying thickness at a wavelength of 530 nm. WGMs are accessible for arbitrary Alq3 thicknesses with the SF6-outcoupling structure, whereas the extraction of SPPs with Alq3 films thicker than 100 nm requires a substrate with very high refractive index, like LiNbO3.

Fig. 6
Fig. 6

White OLED with attached SF6-prism: (a) stack layout (b) photograph of angular dependent light emission into different optical modes.

Fig. 7
Fig. 7

(a) Simulated top emission intensities of trapped modes from Fig. 6(a) – with a semi-infinite bottom substrate – at a wavelength of 600 nm as a function of the refractive index nHI of the HI glass prism on the top side. Acronyms used in the figure: direct top (DT), substrate top (ST), waveguide modes (WGM), surface plasmons (SPP). (b) Angle integrated top and bottom emission of the different extracted modes in comparison to the remaining loss-channels not accessible at the given refractive index of the prism.

Equations (1)

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k x = k 0 ( ɛ 1 ɛ 2 ɛ 1 + ɛ 2 ) 1 / 2 = ω c ( ɛ 1 ( ω ) ɛ 2 ( ω ) ɛ 1 ( ω ) + ɛ 2 ( ω ) ) 1 / 2

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