Abstract

Microcavities for organic light-emitting devices (OLED’s) with a metal mirror on one side and a distributed Bragg reflector (DBR) on the other side have been extensively studied in the literature. Usually the DBR is highly reflective, and the resulting emission of the microcavity depends strongly on angle and wavelength. With a thick metal mirror on one side and a semi-transparent metal mirror on the other side of the OLED, a microcavity can be obtained with an optical thickness of 1 half-wavelength. Because the emission is enhanced over a wide solid angle, with a small spectral dependence, this structure is very promising for display applications. For a TPD/ALq3 structure with a typical intrinsic emission spectrum, embedded in a microcavity with a thick and a semitransparent silver mirror, the integrated emission in air, the color variation with angle, and the change in the decay time are compared with those in a DBR-based microcavity.

© 2000 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. T. Nakayama, Y. Itoh, and A. Kakuta, “Organic photo- and electroluminescent devices with double mirrors,” Appl. Phys. Lett. 63, 594–595 (1993).
    [CrossRef]
  2. T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
    [CrossRef]
  3. J. Grüner, F. Cacialli, and R. Friend, “Emission enhancement in single-layer conjugated polymer microcavities,” J. Appl. Phys. 80, 207–215 (1996).
    [CrossRef]
  4. R. Jordan, L. Rothberg, A. Dodabalapur, and R. Slusher, “Efficiency enhancement of microcavity organic light emitting diodes,” Appl. Phys. Lett. 69, 1997–1999 (1996).
    [CrossRef]
  5. K. Neyts, “Thin film microcavities for display applications,” in Conference Record of the Seventeenth International Display Research Conference (IDRC), J. Morreale, ed. (Society for Information Display, Santa Ana, Calif., 1997), pp. 421–424.
  6. N. Takada, T. Tsutsui, and S. Saito, “Control of emission characteristics in organic thin-film electroluminescent diodes using an optical-microcavity structure,” Appl. Phys. Lett. 63, 2032–2034 (1993).
    [CrossRef]
  7. V. Cimrová and D. Neher, “Microcavity effects in single-layer light-emitting devices based on poly(p-phenylene vinylene),” J. Appl. Phys. 79, 3299–3306 (1996).
    [CrossRef]
  8. P. Burrows, Z. Shen, and S. Forrest, “Saturated full color stacked organic light emitting devices,” in Conference Record of the Seventeenth International Display Research Conference (IDRC), J. Morreale, ed. (Society for Information Display, Santa Ana, Calif., 1997), pp. 318–321.
  9. W. Lukosz, “Light emission by multipole sources in thin layers. I. Radiation patterns of electric and magnetic dipoles,” J. Opt. Soc. Am. 71, 744–754 (1981).
    [CrossRef]
  10. K. Neyts, “Simulation of light emission from thin-film microcavities,” J. Opt. Soc. Am. A 15, 962 (1998).
    [CrossRef]
  11. L. Schulz, “The optical constants of silver, gold, copper and aluminum. I. The absorption coefficient k. II. The index of refraction n,” J. Opt. Soc. Am. 44, 357–370 (1954).
    [CrossRef]
  12. G. Bjork, S. Machida, Y. Yamamoto, and K. Igeta, “Modification of spontaneous emission in the optical microscopic cavity,” Phys. Rev. A 44, 669–681 (1991).
    [CrossRef]
  13. K. Neyts, “Cavity effects in thin film phosphors based on ZnS,” in Microcavities and Photonic Bandgaps, Vol. 324 of NATO Series E (Kluwer Academic, Dordrecht, The Netherlands, 1996), p. 397.

1998 (1)

1996 (3)

V. Cimrová and D. Neher, “Microcavity effects in single-layer light-emitting devices based on poly(p-phenylene vinylene),” J. Appl. Phys. 79, 3299–3306 (1996).
[CrossRef]

J. Grüner, F. Cacialli, and R. Friend, “Emission enhancement in single-layer conjugated polymer microcavities,” J. Appl. Phys. 80, 207–215 (1996).
[CrossRef]

R. Jordan, L. Rothberg, A. Dodabalapur, and R. Slusher, “Efficiency enhancement of microcavity organic light emitting diodes,” Appl. Phys. Lett. 69, 1997–1999 (1996).
[CrossRef]

1995 (1)

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

1993 (2)

T. Nakayama, Y. Itoh, and A. Kakuta, “Organic photo- and electroluminescent devices with double mirrors,” Appl. Phys. Lett. 63, 594–595 (1993).
[CrossRef]

N. Takada, T. Tsutsui, and S. Saito, “Control of emission characteristics in organic thin-film electroluminescent diodes using an optical-microcavity structure,” Appl. Phys. Lett. 63, 2032–2034 (1993).
[CrossRef]

1991 (1)

G. Bjork, S. Machida, Y. Yamamoto, and K. Igeta, “Modification of spontaneous emission in the optical microscopic cavity,” Phys. Rev. A 44, 669–681 (1991).
[CrossRef]

1981 (1)

1954 (1)

Bjork, G.

G. Bjork, S. Machida, Y. Yamamoto, and K. Igeta, “Modification of spontaneous emission in the optical microscopic cavity,” Phys. Rev. A 44, 669–681 (1991).
[CrossRef]

Bradley, D.

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

Cacialli, F.

J. Grüner, F. Cacialli, and R. Friend, “Emission enhancement in single-layer conjugated polymer microcavities,” J. Appl. Phys. 80, 207–215 (1996).
[CrossRef]

Cimrová, V.

V. Cimrová and D. Neher, “Microcavity effects in single-layer light-emitting devices based on poly(p-phenylene vinylene),” J. Appl. Phys. 79, 3299–3306 (1996).
[CrossRef]

Dodabalapur, A.

R. Jordan, L. Rothberg, A. Dodabalapur, and R. Slusher, “Efficiency enhancement of microcavity organic light emitting diodes,” Appl. Phys. Lett. 69, 1997–1999 (1996).
[CrossRef]

Fisher, T.

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

Friend, R.

J. Grüner, F. Cacialli, and R. Friend, “Emission enhancement in single-layer conjugated polymer microcavities,” J. Appl. Phys. 80, 207–215 (1996).
[CrossRef]

Grüner, J.

J. Grüner, F. Cacialli, and R. Friend, “Emission enhancement in single-layer conjugated polymer microcavities,” J. Appl. Phys. 80, 207–215 (1996).
[CrossRef]

Igeta, K.

G. Bjork, S. Machida, Y. Yamamoto, and K. Igeta, “Modification of spontaneous emission in the optical microscopic cavity,” Phys. Rev. A 44, 669–681 (1991).
[CrossRef]

Itoh, Y.

T. Nakayama, Y. Itoh, and A. Kakuta, “Organic photo- and electroluminescent devices with double mirrors,” Appl. Phys. Lett. 63, 594–595 (1993).
[CrossRef]

Jordan, R.

R. Jordan, L. Rothberg, A. Dodabalapur, and R. Slusher, “Efficiency enhancement of microcavity organic light emitting diodes,” Appl. Phys. Lett. 69, 1997–1999 (1996).
[CrossRef]

Kakuta, A.

T. Nakayama, Y. Itoh, and A. Kakuta, “Organic photo- and electroluminescent devices with double mirrors,” Appl. Phys. Lett. 63, 594–595 (1993).
[CrossRef]

Lidzey, D.

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

Lukosz, W.

Machida, S.

G. Bjork, S. Machida, Y. Yamamoto, and K. Igeta, “Modification of spontaneous emission in the optical microscopic cavity,” Phys. Rev. A 44, 669–681 (1991).
[CrossRef]

Nakayama, T.

T. Nakayama, Y. Itoh, and A. Kakuta, “Organic photo- and electroluminescent devices with double mirrors,” Appl. Phys. Lett. 63, 594–595 (1993).
[CrossRef]

Neher, D.

V. Cimrová and D. Neher, “Microcavity effects in single-layer light-emitting devices based on poly(p-phenylene vinylene),” J. Appl. Phys. 79, 3299–3306 (1996).
[CrossRef]

Neyts, K.

Pate, M.

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

Rothberg, L.

R. Jordan, L. Rothberg, A. Dodabalapur, and R. Slusher, “Efficiency enhancement of microcavity organic light emitting diodes,” Appl. Phys. Lett. 69, 1997–1999 (1996).
[CrossRef]

Saito, S.

N. Takada, T. Tsutsui, and S. Saito, “Control of emission characteristics in organic thin-film electroluminescent diodes using an optical-microcavity structure,” Appl. Phys. Lett. 63, 2032–2034 (1993).
[CrossRef]

Schulz, L.

Skolnick, M.

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

Slusher, R.

R. Jordan, L. Rothberg, A. Dodabalapur, and R. Slusher, “Efficiency enhancement of microcavity organic light emitting diodes,” Appl. Phys. Lett. 69, 1997–1999 (1996).
[CrossRef]

Takada, N.

N. Takada, T. Tsutsui, and S. Saito, “Control of emission characteristics in organic thin-film electroluminescent diodes using an optical-microcavity structure,” Appl. Phys. Lett. 63, 2032–2034 (1993).
[CrossRef]

Tsutsui, T.

N. Takada, T. Tsutsui, and S. Saito, “Control of emission characteristics in organic thin-film electroluminescent diodes using an optical-microcavity structure,” Appl. Phys. Lett. 63, 2032–2034 (1993).
[CrossRef]

Weaver, M.

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

Whittaker, D.

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

Yamamoto, Y.

G. Bjork, S. Machida, Y. Yamamoto, and K. Igeta, “Modification of spontaneous emission in the optical microscopic cavity,” Phys. Rev. A 44, 669–681 (1991).
[CrossRef]

Appl. Phys. Lett. (4)

T. Nakayama, Y. Itoh, and A. Kakuta, “Organic photo- and electroluminescent devices with double mirrors,” Appl. Phys. Lett. 63, 594–595 (1993).
[CrossRef]

T. Fisher, D. Lidzey, M. Pate, M. Weaver, D. Whittaker, M. Skolnick, and D. Bradley, “Electroluminescence from a conjugated polymer microcavity structure,” Appl. Phys. Lett. 67, 1355–1357 (1995).
[CrossRef]

R. Jordan, L. Rothberg, A. Dodabalapur, and R. Slusher, “Efficiency enhancement of microcavity organic light emitting diodes,” Appl. Phys. Lett. 69, 1997–1999 (1996).
[CrossRef]

N. Takada, T. Tsutsui, and S. Saito, “Control of emission characteristics in organic thin-film electroluminescent diodes using an optical-microcavity structure,” Appl. Phys. Lett. 63, 2032–2034 (1993).
[CrossRef]

J. Appl. Phys. (2)

V. Cimrová and D. Neher, “Microcavity effects in single-layer light-emitting devices based on poly(p-phenylene vinylene),” J. Appl. Phys. 79, 3299–3306 (1996).
[CrossRef]

J. Grüner, F. Cacialli, and R. Friend, “Emission enhancement in single-layer conjugated polymer microcavities,” J. Appl. Phys. 80, 207–215 (1996).
[CrossRef]

J. Opt. Soc. Am. (2)

J. Opt. Soc. Am. A (1)

Phys. Rev. A (1)

G. Bjork, S. Machida, Y. Yamamoto, and K. Igeta, “Modification of spontaneous emission in the optical microscopic cavity,” Phys. Rev. A 44, 669–681 (1991).
[CrossRef]

Other (3)

K. Neyts, “Cavity effects in thin film phosphors based on ZnS,” in Microcavities and Photonic Bandgaps, Vol. 324 of NATO Series E (Kluwer Academic, Dordrecht, The Netherlands, 1996), p. 397.

P. Burrows, Z. Shen, and S. Forrest, “Saturated full color stacked organic light emitting devices,” in Conference Record of the Seventeenth International Display Research Conference (IDRC), J. Morreale, ed. (Society for Information Display, Santa Ana, Calif., 1997), pp. 318–321.

K. Neyts, “Thin film microcavities for display applications,” in Conference Record of the Seventeenth International Display Research Conference (IDRC), J. Morreale, ed. (Society for Information Display, Santa Ana, Calif., 1997), pp. 421–424.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (5)

Fig. 1
Fig. 1

Structure of the Alq3TPD-based OLED for the silver/silver microcavity (left) and the silver/DBR microcavity (right). The light is generated in the 10-nm-thick Alq3 emitting layer, near the Alq3TPD interface. Above the emitting layer there is a nonemitting Alq3 layer with variable thickness. Below the emitting layer there is a TPD layer and an ITO layer. Because the refractive indices of these materials are nearly the same, the thickness of the ITO is included in the effective TPD layer thickness. The definition of the directions + and - are indicated by the arrows with those labels. The distances indicated on the right illustrate the nonemitting Alq3 thickness; the effective TPD thickness; the total distance between the mirrors, de; and the distance between the light emitting region and the upper mirror, z-.

Fig. 2
Fig. 2

Intrinsic OLED spectrum originating from the rubrene-doped Alq3, used in the calculation of Iair.

Fig. 3
Fig. 3

Simulated relative power distribution Prel(αglass, λ) as a function of the angle in glass and the wavelength, assuming a flat intrinsic spectrum. Top, for the silver/silver structure (7); bottom, for the silver/DBR structure (8).

Fig. 4
Fig. 4

Top, polar plot of the simulated emission in air, integrated over the Alq3 spectrum given in Fig. 2, for the silver/silver structure (7) and the silver/DBR structure (8) compared with the reference case (REF) without reflections. Bottom, simulated variation of the x CIE chromaticity color coordinate with the angle of emission in air for the two structures, based on the Alq3 spectrum.

Fig. 5
Fig. 5

Illustration of the different contributions of the radiative emission: emission into air, Iair; into the glass substrate, Iglass; trapped in the Alq3, IAlq; or absorbed by the silver electrode, IAg.

Tables (1)

Tables Icon

Table 1 Calculated Integrated Intensity in Air, Glass, and Alq3 or Silver for the Reference Structure, the Silver/Silver Microcavity Structure (7), and the Silver/DBR Microcavity Structure (8)a

Equations (13)

Equations on this page are rendered with MathJax. Learn more.

1-re,-TM,TEre,+TM,TE expj4πne cos αedeλ-2.
Prel(αglass, λ)=cos αglass[1-(nglass2/ne2)sin2 αglass]1/2.
Prel(αglass=0, λ)=|1+re,- exp(j4πnez-/λ)|2|1-re,-re,+ exp(j4πnede/λ)|2T+.
thickAg/45nmAlq3/10nmemittingregion/
45nmTPD/50nmAg/glass.
thickAg/45.5nmAlq3/10nmemittingregion/
69.3nmTPD/11-layerDBR/glass,
Iair=λminλmax0°41°Prel(αglass, λ)2π sin αglassSλ(λ)dαglassdλ2π(ne2/nglass2)(1-cos 31.8°)λminλmaxSλ(λ)dλ.
Ag/51nmAlq3/10nmemittingregion/
48nmTPD/29nmAg/glass,
Ag/52nmAlq3/10nmemittingregion/78nmTPD/
70nmTiO2/100nmSiO2/68nmTiO2/glass,
G=τrefτcavity=τrad+Fτnrτrad+τnr.

Metrics