Abstract

We report high-efficiency and high-contrast phosphorescent top-emitting organic light-emitting devices (OLEDs) by employing the low reflectance p-type Si bottom anodes and the high transmittance Cs2CO3/Ag top cathodes for effective hole and electron injection. With the green electrophosphorescent material fac tris (2-phenylpyridine) iridium [Ir(ppy)3] doped emitting layer, the devices exhibit peak external quantum and power efficiencies of 3.5% (12 cd/A) and 4.5 lm/W, which are the highest values reported for OLEDs using Si wafers as electrodes. Moreover, these devices exhibit significantly higher contrast compared to the conventional bottom-emitting and top-emitting OLEDs with the highly reflective back electrodes.

© 2007 Optical Society of America

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  1. C. W. Tang and S. A. VanSlyke, "Organic electroluminescent diodes," Appl. Phys. Lett. 51, 913-915 (1987).
    [CrossRef]
  2. D. R. Baigent, R. N. Marks, N. C. Greenham, R. H. Friend, S. C. Moratti, and A. B. Holmes, "Conjugated polymer light-emitting diodes on silicon substrates," Appl. Phys. Lett. 65, 2636-2638 (1994).
    [CrossRef]
  3. V. Bulovic, P. Tian, P. E. Burrows, M. R. Gokhale, S. R. Forrest, and M. E. Thompson, "A surface-emitting vacuum-deposited organic light emitting device," Appl. Phys. Lett. 70, 2954-2956 (1997).
    [CrossRef]
  4. I. D. Parker and H. H. Kim, "Fabrication of polymer light-emitting diodes using doped silicon electrodes," Appl. Phys. Lett. 64, 1774-1776 (1994).
    [CrossRef]
  5. X. Zhou, J. He, L. S. Liao, M. Lu, Z. H. Xiong, X. M. Ding, X. Y. Hou, F. G. Tao, C. E. Zhou, and S. T. Lee, "Enhanced hole injection in a bilayer vacuum-deposited organic light-emitting device using a p-type doped silicon anode," Appl. Phys. Lett. 74, 609-611 (1999).
    [CrossRef]
  6. G. L. Ma, G. Z. Ran, A. G. Xu, Y. H. Xu, Y. P. Qiao, W. X. Chen, L. Dai, and G. G. Qin, "Improving charge-injection balance and cathode transmittance of top-emitting organic light-emitting device with p-type silicon anode," Appl. Phys. Lett. 87, 081106 (2005).
    [CrossRef]
  7. C. J. Yang, C. L. Lin, C. C. Wu, Y. H. Yeh, C. C. Cheng, Y. H. Kuo, and T. H. Chen, "High-contrast top-emitting organic light-emitting devices for active-matrix displays," Appl. Phys.Lett. 87, 143507 (2005).
    [CrossRef]
  8. A. N. Krasnov, "High-contrast organic light-emitting diodes on flexible subtrate," Appl. Phys. Lett. 80, 3853-3855 (2002).
    [CrossRef]
  9. Z. Y. Xie and L. S. Hung, "High-contrast organic light-emitting diodes," Appl. Phys. Lett. 84, 1207-1209 (2004).
    [CrossRef]
  10. Y. C. Zhou, L. L. Ma, J. Zhou, X. D. Gao, H. R. Wu, X. M. Ding, and X. Y. Hou, "High contrast organic light-emitting devices with improved electrical characteristics," Appl. Phys. Lett. 88, 233505 (2006).
    [CrossRef]
  11. Z. X. Wu, L. D. Wang, and Y. Qiu, "Contrast-enhancement in organic light-emitting diodes," Opt. Express 13, 1406-1411 (2005).
    [CrossRef] [PubMed]
  12. K. C. Lau, W. F. Xie, H. Y. Sun, C. S. Lee, and S. T. Lee, "Contrast improvement of organic light-emitting devices with Sm:Ag cathode," Appl. Phys. Lett. 88, 083507 (2006).
    [CrossRef]
  13. J. H. Lee, X. Y. Zhu, Y. H. Lin, W. K. Choi, T. C. Lin, S. C. Hsu, H. Y. Lin, and S. T. Wu, "High ambient-contrast-ratio display using tandem reflective liquid crystal display and organic light-emitting device," Opt. Express 13, 9431-9438 (2005).
    [CrossRef] [PubMed]
  14. S. Tokito, K. Noda, and Y. Taga, "Metal oxides as a hole injecting layer for an organic electroluminescent device," J. Phys. D 29, 2750-2753 (1996).
    [CrossRef]
  15. T. Hasegawa, S. Miura, T. Moriyama, T. Kimura, I. Takaya, Y. Osato, and H. Mizutani, "Novel Electron-Injection Layers for Top-Emission OLEDs," SID Int. Symp. Digest Tech. Papers 35, 154-157 (2004).
    [CrossRef]
  16. L. S. Hung, C. W. Tang, M. G. Mason, P. Raychaudhuri, and J. Madathil, "Application of an ultrathin LiF/Al bilayer in organic surface-emitting diodes," Appl. Phys. Lett. 78, 544-546 (2001).
    [CrossRef]
  17. M. A. Baldo, S. Lamansky, P. E. Burrows, M. E. Thompson, and S. R. Forrest, "Very high-efficiency green organic light-emitting devices based on electrophosphorescence," Appl. Phys. Lett. 75, 4-6 (1999).
    [CrossRef]
  18. H. Riel, S. Karg, T. Beierlein, B. Ruhstaller, and W. Rieß, "Phosphorescent top-emitting organic light-emitting devices with improved light outcoupling," Appl. Phys. Lett. 82, 466-468 (2003).
    [CrossRef]
  19. J. R, Lian, Y. B. Yuan, L. F. Cao, J. Zhang, H. Q. Pang, Y. F. Zhou, and X. Zhou, "Improved efficiency in OLEDs with a thin Alq3 interlayer," J. Lumin. 122-123, 660-662 (2007).
    [CrossRef]
  20. X. Zhou, M. Pfeiffer, J. Blochwitz, W. Werner, A. Nollau, T. Fritz, and K. Leo, "Very-low-operating-voltage organic light-emitting diodes using a p-doped amorphous hole injection layer," Appl. Phys. Lett. 78, 410-412 (2001).
    [CrossRef]

2007 (1)

J. R, Lian, Y. B. Yuan, L. F. Cao, J. Zhang, H. Q. Pang, Y. F. Zhou, and X. Zhou, "Improved efficiency in OLEDs with a thin Alq3 interlayer," J. Lumin. 122-123, 660-662 (2007).
[CrossRef]

2006 (2)

Y. C. Zhou, L. L. Ma, J. Zhou, X. D. Gao, H. R. Wu, X. M. Ding, and X. Y. Hou, "High contrast organic light-emitting devices with improved electrical characteristics," Appl. Phys. Lett. 88, 233505 (2006).
[CrossRef]

K. C. Lau, W. F. Xie, H. Y. Sun, C. S. Lee, and S. T. Lee, "Contrast improvement of organic light-emitting devices with Sm:Ag cathode," Appl. Phys. Lett. 88, 083507 (2006).
[CrossRef]

2005 (4)

J. H. Lee, X. Y. Zhu, Y. H. Lin, W. K. Choi, T. C. Lin, S. C. Hsu, H. Y. Lin, and S. T. Wu, "High ambient-contrast-ratio display using tandem reflective liquid crystal display and organic light-emitting device," Opt. Express 13, 9431-9438 (2005).
[CrossRef] [PubMed]

Z. X. Wu, L. D. Wang, and Y. Qiu, "Contrast-enhancement in organic light-emitting diodes," Opt. Express 13, 1406-1411 (2005).
[CrossRef] [PubMed]

G. L. Ma, G. Z. Ran, A. G. Xu, Y. H. Xu, Y. P. Qiao, W. X. Chen, L. Dai, and G. G. Qin, "Improving charge-injection balance and cathode transmittance of top-emitting organic light-emitting device with p-type silicon anode," Appl. Phys. Lett. 87, 081106 (2005).
[CrossRef]

C. J. Yang, C. L. Lin, C. C. Wu, Y. H. Yeh, C. C. Cheng, Y. H. Kuo, and T. H. Chen, "High-contrast top-emitting organic light-emitting devices for active-matrix displays," Appl. Phys.Lett. 87, 143507 (2005).
[CrossRef]

2004 (2)

Z. Y. Xie and L. S. Hung, "High-contrast organic light-emitting diodes," Appl. Phys. Lett. 84, 1207-1209 (2004).
[CrossRef]

T. Hasegawa, S. Miura, T. Moriyama, T. Kimura, I. Takaya, Y. Osato, and H. Mizutani, "Novel Electron-Injection Layers for Top-Emission OLEDs," SID Int. Symp. Digest Tech. Papers 35, 154-157 (2004).
[CrossRef]

2003 (1)

H. Riel, S. Karg, T. Beierlein, B. Ruhstaller, and W. Rieß, "Phosphorescent top-emitting organic light-emitting devices with improved light outcoupling," Appl. Phys. Lett. 82, 466-468 (2003).
[CrossRef]

2002 (1)

A. N. Krasnov, "High-contrast organic light-emitting diodes on flexible subtrate," Appl. Phys. Lett. 80, 3853-3855 (2002).
[CrossRef]

2001 (2)

L. S. Hung, C. W. Tang, M. G. Mason, P. Raychaudhuri, and J. Madathil, "Application of an ultrathin LiF/Al bilayer in organic surface-emitting diodes," Appl. Phys. Lett. 78, 544-546 (2001).
[CrossRef]

X. Zhou, M. Pfeiffer, J. Blochwitz, W. Werner, A. Nollau, T. Fritz, and K. Leo, "Very-low-operating-voltage organic light-emitting diodes using a p-doped amorphous hole injection layer," Appl. Phys. Lett. 78, 410-412 (2001).
[CrossRef]

1999 (2)

M. A. Baldo, S. Lamansky, P. E. Burrows, M. E. Thompson, and S. R. Forrest, "Very high-efficiency green organic light-emitting devices based on electrophosphorescence," Appl. Phys. Lett. 75, 4-6 (1999).
[CrossRef]

X. Zhou, J. He, L. S. Liao, M. Lu, Z. H. Xiong, X. M. Ding, X. Y. Hou, F. G. Tao, C. E. Zhou, and S. T. Lee, "Enhanced hole injection in a bilayer vacuum-deposited organic light-emitting device using a p-type doped silicon anode," Appl. Phys. Lett. 74, 609-611 (1999).
[CrossRef]

1997 (1)

V. Bulovic, P. Tian, P. E. Burrows, M. R. Gokhale, S. R. Forrest, and M. E. Thompson, "A surface-emitting vacuum-deposited organic light emitting device," Appl. Phys. Lett. 70, 2954-2956 (1997).
[CrossRef]

1996 (1)

S. Tokito, K. Noda, and Y. Taga, "Metal oxides as a hole injecting layer for an organic electroluminescent device," J. Phys. D 29, 2750-2753 (1996).
[CrossRef]

1994 (2)

I. D. Parker and H. H. Kim, "Fabrication of polymer light-emitting diodes using doped silicon electrodes," Appl. Phys. Lett. 64, 1774-1776 (1994).
[CrossRef]

D. R. Baigent, R. N. Marks, N. C. Greenham, R. H. Friend, S. C. Moratti, and A. B. Holmes, "Conjugated polymer light-emitting diodes on silicon substrates," Appl. Phys. Lett. 65, 2636-2638 (1994).
[CrossRef]

1987 (1)

C. W. Tang and S. A. VanSlyke, "Organic electroluminescent diodes," Appl. Phys. Lett. 51, 913-915 (1987).
[CrossRef]

Appl. Phys. Lett. (14)

C. W. Tang and S. A. VanSlyke, "Organic electroluminescent diodes," Appl. Phys. Lett. 51, 913-915 (1987).
[CrossRef]

D. R. Baigent, R. N. Marks, N. C. Greenham, R. H. Friend, S. C. Moratti, and A. B. Holmes, "Conjugated polymer light-emitting diodes on silicon substrates," Appl. Phys. Lett. 65, 2636-2638 (1994).
[CrossRef]

V. Bulovic, P. Tian, P. E. Burrows, M. R. Gokhale, S. R. Forrest, and M. E. Thompson, "A surface-emitting vacuum-deposited organic light emitting device," Appl. Phys. Lett. 70, 2954-2956 (1997).
[CrossRef]

I. D. Parker and H. H. Kim, "Fabrication of polymer light-emitting diodes using doped silicon electrodes," Appl. Phys. Lett. 64, 1774-1776 (1994).
[CrossRef]

X. Zhou, J. He, L. S. Liao, M. Lu, Z. H. Xiong, X. M. Ding, X. Y. Hou, F. G. Tao, C. E. Zhou, and S. T. Lee, "Enhanced hole injection in a bilayer vacuum-deposited organic light-emitting device using a p-type doped silicon anode," Appl. Phys. Lett. 74, 609-611 (1999).
[CrossRef]

G. L. Ma, G. Z. Ran, A. G. Xu, Y. H. Xu, Y. P. Qiao, W. X. Chen, L. Dai, and G. G. Qin, "Improving charge-injection balance and cathode transmittance of top-emitting organic light-emitting device with p-type silicon anode," Appl. Phys. Lett. 87, 081106 (2005).
[CrossRef]

A. N. Krasnov, "High-contrast organic light-emitting diodes on flexible subtrate," Appl. Phys. Lett. 80, 3853-3855 (2002).
[CrossRef]

Z. Y. Xie and L. S. Hung, "High-contrast organic light-emitting diodes," Appl. Phys. Lett. 84, 1207-1209 (2004).
[CrossRef]

Y. C. Zhou, L. L. Ma, J. Zhou, X. D. Gao, H. R. Wu, X. M. Ding, and X. Y. Hou, "High contrast organic light-emitting devices with improved electrical characteristics," Appl. Phys. Lett. 88, 233505 (2006).
[CrossRef]

K. C. Lau, W. F. Xie, H. Y. Sun, C. S. Lee, and S. T. Lee, "Contrast improvement of organic light-emitting devices with Sm:Ag cathode," Appl. Phys. Lett. 88, 083507 (2006).
[CrossRef]

L. S. Hung, C. W. Tang, M. G. Mason, P. Raychaudhuri, and J. Madathil, "Application of an ultrathin LiF/Al bilayer in organic surface-emitting diodes," Appl. Phys. Lett. 78, 544-546 (2001).
[CrossRef]

M. A. Baldo, S. Lamansky, P. E. Burrows, M. E. Thompson, and S. R. Forrest, "Very high-efficiency green organic light-emitting devices based on electrophosphorescence," Appl. Phys. Lett. 75, 4-6 (1999).
[CrossRef]

H. Riel, S. Karg, T. Beierlein, B. Ruhstaller, and W. Rieß, "Phosphorescent top-emitting organic light-emitting devices with improved light outcoupling," Appl. Phys. Lett. 82, 466-468 (2003).
[CrossRef]

X. Zhou, M. Pfeiffer, J. Blochwitz, W. Werner, A. Nollau, T. Fritz, and K. Leo, "Very-low-operating-voltage organic light-emitting diodes using a p-doped amorphous hole injection layer," Appl. Phys. Lett. 78, 410-412 (2001).
[CrossRef]

Appl. Phys.Lett. (1)

C. J. Yang, C. L. Lin, C. C. Wu, Y. H. Yeh, C. C. Cheng, Y. H. Kuo, and T. H. Chen, "High-contrast top-emitting organic light-emitting devices for active-matrix displays," Appl. Phys.Lett. 87, 143507 (2005).
[CrossRef]

J. Lumin. (1)

J. R, Lian, Y. B. Yuan, L. F. Cao, J. Zhang, H. Q. Pang, Y. F. Zhou, and X. Zhou, "Improved efficiency in OLEDs with a thin Alq3 interlayer," J. Lumin. 122-123, 660-662 (2007).
[CrossRef]

J. Phys. D (1)

S. Tokito, K. Noda, and Y. Taga, "Metal oxides as a hole injecting layer for an organic electroluminescent device," J. Phys. D 29, 2750-2753 (1996).
[CrossRef]

Opt. Express (2)

SID Int. Symp. Digest Tech. Papers (1)

T. Hasegawa, S. Miura, T. Moriyama, T. Kimura, I. Takaya, Y. Osato, and H. Mizutani, "Novel Electron-Injection Layers for Top-Emission OLEDs," SID Int. Symp. Digest Tech. Papers 35, 154-157 (2004).
[CrossRef]

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Figures (4)

Fig. 1.
Fig. 1.

Schematic illustration of the device structures.

Fig. 2.
Fig. 2.

(a) Current density-luminance-voltage and (b) EL efficiency characteristics of the devices.

Fig. 3.
Fig. 3.

(a) Measured reflectance spectra and (b) calculated contrast-ratios of the devices under 140 lx of ambient lighting.

Fig. 4.
Fig. 4.

(Color online) (a) Photos of the devices (with the active area of 6×6 m2) under 565 lx of white fluorescent light illumination. (b) EL spectra of the devices.

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