Abstract

An ultra-thin NaF film was thermally deposited between ITO and NPB as the buffer layer and then treated with the ultraviolet (UV) ozone, in the fabrication of organic light emitting diodes (ITO/NaF/NPB/Alq3/LiF/Al) to study its effect on hole-injection properties. The treatment drastically transforms the role of NaF film from hole-blocking to hole-injecting. This transformation is elucidated using hole-only devices, energy band measurement, surface energy, surface polarity, and X-ray photoelectron spectra. With the optimal thickness (3 nm) of the UV-ozone-treated NaF layer, the device performance is significantly improved, with a turn-on voltage, maximum luminance, and maximum current efficiency of 2.5 V, 15700 cd/m2, and 4.9 cd/A, respectively. Results show that NaF film is not only a hole-blocking layer, but also a promising hole-injecting layer after UV-ozone treatment.

© 2010 OSA

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. C. W. Tang and S. A. VanSlyke, “Organic electroluminescent diodes,” Appl. Phys. Lett. 51(12), 913–915 (1987).
    [CrossRef]
  2. C. W. Tang, S. A. VanSlyke, and C. H. Chen, “Electroluminescence of doped organic thin films,” J. Appl. Phys. 65(9), 3610–3616 (1989).
    [CrossRef]
  3. S. A. Van Slyke, C. H. Chen, and C. W. Tang, “Organic electroluminescent devices with improved stability,” Appl. Phys. Lett. 69(15), 2160–2162 (1996).
    [CrossRef]
  4. L. S. Hung, C. W. Tang, and M. G. Mason, “Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode,” Appl. Phys. Lett. 70(2), 152–154 (1997).
    [CrossRef]
  5. M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
    [CrossRef]
  6. S. T. Lee, Z. Q. Gao, and L. S. Hung, “Metal diffusion from electrodes in organic light-emitting diodes,” Appl. Phys. Lett. 75(10), 1404–1406 (1999).
    [CrossRef]
  7. F. Li, H. Tang, J. Shinar, O. Resto, and S. Z. Weisz, “Effects of aquaregia treatment of indium–tin–oxide substrates on the behavior of double layered organic light-emitting diodes,” Appl. Phys. Lett. 70(20), 2741–2743 (1997).
    [CrossRef]
  8. H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
    [CrossRef]
  9. H. You, Y. Dai, Z. Zhang, and D. Ma, “Improved performances of organic light-emitting diodes with metal oxide as anode buffer,” J. Appl. Phys. 101(2), 026105 (2007).
    [CrossRef]
  10. H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
    [CrossRef]
  11. D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
    [CrossRef]
  12. S. Zhan, X. Ying-Ge, L. Xia, and Y. Tao, “A novel hole-blocking layer NaF between the α-naphthylphenyliphenyl diamine and ITO,” Appl. Surf. Sci. 253(9), 4374–4376 (2007).
    [CrossRef]
  13. S. K. So, W. K. Choi, C. H. Cheng, L. M. Leung, and C. F. Kwong, “Surface preparation and characterization of indium tin oxide substrates for organic electroluminescent devices,” Appl. Phys., A Mater. Sci. Process. 68(4), 447–450 (1999).
    [CrossRef]
  14. Z. Z. You, “Combined AFM, XPS, and contact angle studies on treated indium-tin-oxide films for organic light-emitting devices,” Mater. Lett. 61(18), 3809–3814 (2007).
    [CrossRef]
  15. J. S. Kim, R. H. Friend, and F. Cacialli, “Surface energy and polarity of treated indium–tin–oxide anodes for polymer light-emitting diodes studied by contact-angle measurements,” J. Appl. Phys. 86(5), 2774–2778 (1999).
    [CrossRef]
  16. K. Okumoto, H. Kanno, Y. Hamada, H. Takahashi, and K. Shibata, “High efficiency red organic light-emitting devices using tetraphenyldibenzoperiflanthene-doped rubrene as an emitting layer,” Appl. Phys. Lett. 89(1), 013502–013503 (2006).
    [CrossRef]
  17. S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
    [CrossRef]
  18. J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
    [CrossRef]
  19. C. H. Yi, C. H. Jeong, Y. H. Lee, Y. W. Ko, and G. Y. Yeom, “Oxide surface cleaning by an atmospheric pressure plasma,” Surf. Coat. Tech. 177–178, 711–715 (2004).
    [CrossRef]
  20. H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, and R.-C. Chang, “Improved hole-injection and power efficiency of organic light-emitting diodes using an ultrathin Li-doped ZnO buffer layer,” J. Electrochem. Soc. 154(3), J105–J108 (2007).
    [CrossRef]

2009

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
[CrossRef]

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

2007

S. Zhan, X. Ying-Ge, L. Xia, and Y. Tao, “A novel hole-blocking layer NaF between the α-naphthylphenyliphenyl diamine and ITO,” Appl. Surf. Sci. 253(9), 4374–4376 (2007).
[CrossRef]

Z. Z. You, “Combined AFM, XPS, and contact angle studies on treated indium-tin-oxide films for organic light-emitting devices,” Mater. Lett. 61(18), 3809–3814 (2007).
[CrossRef]

H. You, Y. Dai, Z. Zhang, and D. Ma, “Improved performances of organic light-emitting diodes with metal oxide as anode buffer,” J. Appl. Phys. 101(2), 026105 (2007).
[CrossRef]

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, and R.-C. Chang, “Improved hole-injection and power efficiency of organic light-emitting diodes using an ultrathin Li-doped ZnO buffer layer,” J. Electrochem. Soc. 154(3), J105–J108 (2007).
[CrossRef]

2006

K. Okumoto, H. Kanno, Y. Hamada, H. Takahashi, and K. Shibata, “High efficiency red organic light-emitting devices using tetraphenyldibenzoperiflanthene-doped rubrene as an emitting layer,” Appl. Phys. Lett. 89(1), 013502–013503 (2006).
[CrossRef]

2004

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

C. H. Yi, C. H. Jeong, Y. H. Lee, Y. W. Ko, and G. Y. Yeom, “Oxide surface cleaning by an atmospheric pressure plasma,” Surf. Coat. Tech. 177–178, 711–715 (2004).
[CrossRef]

2001

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

1999

M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
[CrossRef]

S. T. Lee, Z. Q. Gao, and L. S. Hung, “Metal diffusion from electrodes in organic light-emitting diodes,” Appl. Phys. Lett. 75(10), 1404–1406 (1999).
[CrossRef]

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

J. S. Kim, R. H. Friend, and F. Cacialli, “Surface energy and polarity of treated indium–tin–oxide anodes for polymer light-emitting diodes studied by contact-angle measurements,” J. Appl. Phys. 86(5), 2774–2778 (1999).
[CrossRef]

S. K. So, W. K. Choi, C. H. Cheng, L. M. Leung, and C. F. Kwong, “Surface preparation and characterization of indium tin oxide substrates for organic electroluminescent devices,” Appl. Phys., A Mater. Sci. Process. 68(4), 447–450 (1999).
[CrossRef]

1997

F. Li, H. Tang, J. Shinar, O. Resto, and S. Z. Weisz, “Effects of aquaregia treatment of indium–tin–oxide substrates on the behavior of double layered organic light-emitting diodes,” Appl. Phys. Lett. 70(20), 2741–2743 (1997).
[CrossRef]

L. S. Hung, C. W. Tang, and M. G. Mason, “Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode,” Appl. Phys. Lett. 70(2), 152–154 (1997).
[CrossRef]

1996

S. A. Van Slyke, C. H. Chen, and C. W. Tang, “Organic electroluminescent devices with improved stability,” Appl. Phys. Lett. 69(15), 2160–2162 (1996).
[CrossRef]

1989

C. W. Tang, S. A. VanSlyke, and C. H. Chen, “Electroluminescence of doped organic thin films,” J. Appl. Phys. 65(9), 3610–3616 (1989).
[CrossRef]

1987

C. W. Tang and S. A. VanSlyke, “Organic electroluminescent diodes,” Appl. Phys. Lett. 51(12), 913–915 (1987).
[CrossRef]

Aziz, H.

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

Bai, Y.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Bao, G. W.

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

Cacialli, F.

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

J. S. Kim, R. H. Friend, and F. Cacialli, “Surface energy and polarity of treated indium–tin–oxide anodes for polymer light-emitting diodes studied by contact-angle measurements,” J. Appl. Phys. 86(5), 2774–2778 (1999).
[CrossRef]

Chang, R.-C.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, and R.-C. Chang, “Improved hole-injection and power efficiency of organic light-emitting diodes using an ultrathin Li-doped ZnO buffer layer,” J. Electrochem. Soc. 154(3), J105–J108 (2007).
[CrossRef]

Chen, C. H.

S. A. Van Slyke, C. H. Chen, and C. W. Tang, “Organic electroluminescent devices with improved stability,” Appl. Phys. Lett. 69(15), 2160–2162 (1996).
[CrossRef]

C. W. Tang, S. A. VanSlyke, and C. H. Chen, “Electroluminescence of doped organic thin films,” J. Appl. Phys. 65(9), 3610–3616 (1989).
[CrossRef]

Chen, Y.-C.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
[CrossRef]

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, and R.-C. Chang, “Improved hole-injection and power efficiency of organic light-emitting diodes using an ultrathin Li-doped ZnO buffer layer,” J. Electrochem. Soc. 154(3), J105–J108 (2007).
[CrossRef]

Cheng, C. H.

S. K. So, W. K. Choi, C. H. Cheng, L. M. Leung, and C. F. Kwong, “Surface preparation and characterization of indium tin oxide substrates for organic electroluminescent devices,” Appl. Phys., A Mater. Sci. Process. 68(4), 447–450 (1999).
[CrossRef]

Choi, W. K.

S. K. So, W. K. Choi, C. H. Cheng, L. M. Leung, and C. F. Kwong, “Surface preparation and characterization of indium tin oxide substrates for organic electroluminescent devices,” Appl. Phys., A Mater. Sci. Process. 68(4), 447–450 (1999).
[CrossRef]

Chu, S.-Y.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
[CrossRef]

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, and R.-C. Chang, “Improved hole-injection and power efficiency of organic light-emitting diodes using an ultrathin Li-doped ZnO buffer layer,” J. Electrochem. Soc. 154(3), J105–J108 (2007).
[CrossRef]

Dai, Y.

H. You, Y. Dai, Z. Zhang, and D. Ma, “Improved performances of organic light-emitting diodes with metal oxide as anode buffer,” J. Appl. Phys. 101(2), 026105 (2007).
[CrossRef]

Ding, X. M.

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Feng, J.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Feng, X. D.

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

Friend, R. H.

J. S. Kim, R. H. Friend, and F. Cacialli, “Surface energy and polarity of treated indium–tin–oxide anodes for polymer light-emitting diodes studied by contact-angle measurements,” J. Appl. Phys. 86(5), 2774–2778 (1999).
[CrossRef]

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

Gao, Z. Q.

S. T. Lee, Z. Q. Gao, and L. S. Hung, “Metal diffusion from electrodes in organic light-emitting diodes,” Appl. Phys. Lett. 75(10), 1404–1406 (1999).
[CrossRef]

Grozea, D.

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

Hamada, Y.

K. Okumoto, H. Kanno, Y. Hamada, H. Takahashi, and K. Shibata, “High efficiency red organic light-emitting devices using tetraphenyldibenzoperiflanthene-doped rubrene as an emitting layer,” Appl. Phys. Lett. 89(1), 013502–013503 (2006).
[CrossRef]

Ho, P. K. H.

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

Hor, A. M.

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

Hou, X. Y.

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Huang, H.-H.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
[CrossRef]

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, and R.-C. Chang, “Improved hole-injection and power efficiency of organic light-emitting diodes using an ultrathin Li-doped ZnO buffer layer,” J. Electrochem. Soc. 154(3), J105–J108 (2007).
[CrossRef]

Hung, L. S.

M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
[CrossRef]

S. T. Lee, Z. Q. Gao, and L. S. Hung, “Metal diffusion from electrodes in organic light-emitting diodes,” Appl. Phys. Lett. 75(10), 1404–1406 (1999).
[CrossRef]

L. S. Hung, C. W. Tang, and M. G. Mason, “Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode,” Appl. Phys. Lett. 70(2), 152–154 (1997).
[CrossRef]

Jeong, C. H.

C. H. Yi, C. H. Jeong, Y. H. Lee, Y. W. Ko, and G. Y. Yeom, “Oxide surface cleaning by an atmospheric pressure plasma,” Surf. Coat. Tech. 177–178, 711–715 (2004).
[CrossRef]

Jin, Y.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Kanno, H.

K. Okumoto, H. Kanno, Y. Hamada, H. Takahashi, and K. Shibata, “High efficiency red organic light-emitting devices using tetraphenyldibenzoperiflanthene-doped rubrene as an emitting layer,” Appl. Phys. Lett. 89(1), 013502–013503 (2006).
[CrossRef]

Kao, P.-C.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
[CrossRef]

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, and R.-C. Chang, “Improved hole-injection and power efficiency of organic light-emitting diodes using an ultrathin Li-doped ZnO buffer layer,” J. Electrochem. Soc. 154(3), J105–J108 (2007).
[CrossRef]

Kim, J. S.

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

J. S. Kim, R. H. Friend, and F. Cacialli, “Surface energy and polarity of treated indium–tin–oxide anodes for polymer light-emitting diodes studied by contact-angle measurements,” J. Appl. Phys. 86(5), 2774–2778 (1999).
[CrossRef]

Ko, Y. W.

C. H. Yi, C. H. Jeong, Y. H. Lee, Y. W. Ko, and G. Y. Yeom, “Oxide surface cleaning by an atmospheric pressure plasma,” Surf. Coat. Tech. 177–178, 711–715 (2004).
[CrossRef]

Kwong, C. F.

S. K. So, W. K. Choi, C. H. Cheng, L. M. Leung, and C. F. Kwong, “Surface preparation and characterization of indium tin oxide substrates for organic electroluminescent devices,” Appl. Phys., A Mater. Sci. Process. 68(4), 447–450 (1999).
[CrossRef]

Lee, S. T.

S. T. Lee, Z. Q. Gao, and L. S. Hung, “Metal diffusion from electrodes in organic light-emitting diodes,” Appl. Phys. Lett. 75(10), 1404–1406 (1999).
[CrossRef]

M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
[CrossRef]

Lee, Y. H.

C. H. Yi, C. H. Jeong, Y. H. Lee, Y. W. Ko, and G. Y. Yeom, “Oxide surface cleaning by an atmospheric pressure plasma,” Surf. Coat. Tech. 177–178, 711–715 (2004).
[CrossRef]

Leung, L. M.

S. K. So, W. K. Choi, C. H. Cheng, L. M. Leung, and C. F. Kwong, “Surface preparation and characterization of indium tin oxide substrates for organic electroluminescent devices,” Appl. Phys., A Mater. Sci. Process. 68(4), 447–450 (1999).
[CrossRef]

Li, F.

F. Li, H. Tang, J. Shinar, O. Resto, and S. Z. Weisz, “Effects of aquaregia treatment of indium–tin–oxide substrates on the behavior of double layered organic light-emitting diodes,” Appl. Phys. Lett. 70(20), 2741–2743 (1997).
[CrossRef]

Li, S. F. Y.

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

Liu, S.-Y.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Liu, Y.-F.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Lu, Z. H.

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

Ma, D.

H. You, Y. Dai, Z. Zhang, and D. Ma, “Improved performances of organic light-emitting diodes with metal oxide as anode buffer,” J. Appl. Phys. 101(2), 026105 (2007).
[CrossRef]

Mason, M. G.

M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
[CrossRef]

L. S. Hung, C. W. Tang, and M. G. Mason, “Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode,” Appl. Phys. Lett. 70(2), 152–154 (1997).
[CrossRef]

Okumoto, K.

K. Okumoto, H. Kanno, Y. Hamada, H. Takahashi, and K. Shibata, “High efficiency red organic light-emitting devices using tetraphenyldibenzoperiflanthene-doped rubrene as an emitting layer,” Appl. Phys. Lett. 89(1), 013502–013503 (2006).
[CrossRef]

Resto, O.

F. Li, H. Tang, J. Shinar, O. Resto, and S. Z. Weisz, “Effects of aquaregia treatment of indium–tin–oxide substrates on the behavior of double layered organic light-emitting diodes,” Appl. Phys. Lett. 70(20), 2741–2743 (1997).
[CrossRef]

Shibata, K.

K. Okumoto, H. Kanno, Y. Hamada, H. Takahashi, and K. Shibata, “High efficiency red organic light-emitting devices using tetraphenyldibenzoperiflanthene-doped rubrene as an emitting layer,” Appl. Phys. Lett. 89(1), 013502–013503 (2006).
[CrossRef]

Shinar, J.

F. Li, H. Tang, J. Shinar, O. Resto, and S. Z. Weisz, “Effects of aquaregia treatment of indium–tin–oxide substrates on the behavior of double layered organic light-emitting diodes,” Appl. Phys. Lett. 70(20), 2741–2743 (1997).
[CrossRef]

So, S. K.

S. K. So, W. K. Choi, C. H. Cheng, L. M. Leung, and C. F. Kwong, “Surface preparation and characterization of indium tin oxide substrates for organic electroluminescent devices,” Appl. Phys., A Mater. Sci. Process. 68(4), 447–450 (1999).
[CrossRef]

Sodhi, R. N. S.

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

Sun, H.-B.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Takahashi, H.

K. Okumoto, H. Kanno, Y. Hamada, H. Takahashi, and K. Shibata, “High efficiency red organic light-emitting devices using tetraphenyldibenzoperiflanthene-doped rubrene as an emitting layer,” Appl. Phys. Lett. 89(1), 013502–013503 (2006).
[CrossRef]

Tang, C. W.

M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
[CrossRef]

L. S. Hung, C. W. Tang, and M. G. Mason, “Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode,” Appl. Phys. Lett. 70(2), 152–154 (1997).
[CrossRef]

S. A. Van Slyke, C. H. Chen, and C. W. Tang, “Organic electroluminescent devices with improved stability,” Appl. Phys. Lett. 69(15), 2160–2162 (1996).
[CrossRef]

C. W. Tang, S. A. VanSlyke, and C. H. Chen, “Electroluminescence of doped organic thin films,” J. Appl. Phys. 65(9), 3610–3616 (1989).
[CrossRef]

C. W. Tang and S. A. VanSlyke, “Organic electroluminescent diodes,” Appl. Phys. Lett. 51(12), 913–915 (1987).
[CrossRef]

Tang, H.

F. Li, H. Tang, J. Shinar, O. Resto, and S. Z. Weisz, “Effects of aquaregia treatment of indium–tin–oxide substrates on the behavior of double layered organic light-emitting diodes,” Appl. Phys. Lett. 70(20), 2741–2743 (1997).
[CrossRef]

Tao, Y.

S. Zhan, X. Ying-Ge, L. Xia, and Y. Tao, “A novel hole-blocking layer NaF between the α-naphthylphenyliphenyl diamine and ITO,” Appl. Surf. Sci. 253(9), 4374–4376 (2007).
[CrossRef]

Thomas, D. S.

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

Tseng, Z.-L.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
[CrossRef]

Van Slyke, S. A.

S. A. Van Slyke, C. H. Chen, and C. W. Tang, “Organic electroluminescent devices with improved stability,” Appl. Phys. Lett. 69(15), 2160–2162 (1996).
[CrossRef]

VanSlyke, S. A.

C. W. Tang, S. A. VanSlyke, and C. H. Chen, “Electroluminescence of doped organic thin films,” J. Appl. Phys. 65(9), 3610–3616 (1989).
[CrossRef]

C. W. Tang and S. A. VanSlyke, “Organic electroluminescent diodes,” Appl. Phys. Lett. 51(12), 913–915 (1987).
[CrossRef]

Wang, M.

M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
[CrossRef]

Wang, Z. J.

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Weisz, S. Z.

F. Li, H. Tang, J. Shinar, O. Resto, and S. Z. Weisz, “Effects of aquaregia treatment of indium–tin–oxide substrates on the behavior of double layered organic light-emitting diodes,” Appl. Phys. Lett. 70(20), 2741–2743 (1997).
[CrossRef]

Wong, K. W.

M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
[CrossRef]

Wu, Y.

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Xia, L.

S. Zhan, X. Ying-Ge, L. Xia, and Y. Tao, “A novel hole-blocking layer NaF between the α-naphthylphenyliphenyl diamine and ITO,” Appl. Surf. Sci. 253(9), 4374–4376 (2007).
[CrossRef]

Xie, G.-H.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Xue, Q.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Yang, M.-R.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
[CrossRef]

Yeom, G. Y.

C. H. Yi, C. H. Jeong, Y. H. Lee, Y. W. Ko, and G. Y. Yeom, “Oxide surface cleaning by an atmospheric pressure plasma,” Surf. Coat. Tech. 177–178, 711–715 (2004).
[CrossRef]

Yi, C. H.

C. H. Yi, C. H. Jeong, Y. H. Lee, Y. W. Ko, and G. Y. Yeom, “Oxide surface cleaning by an atmospheric pressure plasma,” Surf. Coat. Tech. 177–178, 711–715 (2004).
[CrossRef]

Ying-Ge, X.

S. Zhan, X. Ying-Ge, L. Xia, and Y. Tao, “A novel hole-blocking layer NaF between the α-naphthylphenyliphenyl diamine and ITO,” Appl. Surf. Sci. 253(9), 4374–4376 (2007).
[CrossRef]

You, H.

H. You, Y. Dai, Z. Zhang, and D. Ma, “Improved performances of organic light-emitting diodes with metal oxide as anode buffer,” J. Appl. Phys. 101(2), 026105 (2007).
[CrossRef]

You, Z. Z.

Z. Z. You, “Combined AFM, XPS, and contact angle studies on treated indium-tin-oxide films for organic light-emitting devices,” Mater. Lett. 61(18), 3809–3814 (2007).
[CrossRef]

Yu, H. Y.

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

Zhan, S.

S. Zhan, X. Ying-Ge, L. Xia, and Y. Tao, “A novel hole-blocking layer NaF between the α-naphthylphenyliphenyl diamine and ITO,” Appl. Surf. Sci. 253(9), 4374–4376 (2007).
[CrossRef]

Zhan, Y. Q.

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Zhang, D.-D.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Zhang, S. T.

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Zhang, Z.

H. You, Y. Dai, Z. Zhang, and D. Ma, “Improved performances of organic light-emitting diodes with metal oxide as anode buffer,” J. Appl. Phys. 101(2), 026105 (2007).
[CrossRef]

Zhao, J. M.

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Zhao, Y.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Zhong, Y.-Q.

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

Zhou, Y. C.

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Appl. Phys. Lett.

C. W. Tang and S. A. VanSlyke, “Organic electroluminescent diodes,” Appl. Phys. Lett. 51(12), 913–915 (1987).
[CrossRef]

S. A. Van Slyke, C. H. Chen, and C. W. Tang, “Organic electroluminescent devices with improved stability,” Appl. Phys. Lett. 69(15), 2160–2162 (1996).
[CrossRef]

L. S. Hung, C. W. Tang, and M. G. Mason, “Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode,” Appl. Phys. Lett. 70(2), 152–154 (1997).
[CrossRef]

S. T. Lee, Z. Q. Gao, and L. S. Hung, “Metal diffusion from electrodes in organic light-emitting diodes,” Appl. Phys. Lett. 75(10), 1404–1406 (1999).
[CrossRef]

F. Li, H. Tang, J. Shinar, O. Resto, and S. Z. Weisz, “Effects of aquaregia treatment of indium–tin–oxide substrates on the behavior of double layered organic light-emitting diodes,” Appl. Phys. Lett. 70(20), 2741–2743 (1997).
[CrossRef]

H. Y. Yu, X. D. Feng, D. Grozea, Z. H. Lu, R. N. S. Sodhi, A. M. Hor, and H. Aziz, “Surface electronic structure of plasma-treated indium tin oxides,” Appl. Phys. Lett. 78(17), 2595–2597 (2001).
[CrossRef]

D.-D. Zhang, J. Feng, Y.-F. Liu, Y.-Q. Zhong, Y. Bai, Y. Jin, G.-H. Xie, Q. Xue, Y. Zhao, S.-Y. Liu, and H.-B. Sun, “Enhanced hole injection in organic light-emitting devices by using Fe[sub 3]O[sub 4] as an anodic buffer layer,” Appl. Phys. Lett. 94(22), 223306 (2009).
[CrossRef]

K. Okumoto, H. Kanno, Y. Hamada, H. Takahashi, and K. Shibata, “High efficiency red organic light-emitting devices using tetraphenyldibenzoperiflanthene-doped rubrene as an emitting layer,” Appl. Phys. Lett. 89(1), 013502–013503 (2006).
[CrossRef]

S. T. Zhang, Z. J. Wang, J. M. Zhao, Y. Q. Zhan, Y. Wu, Y. C. Zhou, X. M. Ding, and X. Y. Hou, “Electron blocking and hole injection: the role of N, N'-bis(naphthalen-1-y)-N, N'-bis(phenyl)benzidine in organic light-emitting devices,” Appl. Phys. Lett. 84(15), 2916–2918 (2004).
[CrossRef]

Appl. Phys., A Mater. Sci. Process.

S. K. So, W. K. Choi, C. H. Cheng, L. M. Leung, and C. F. Kwong, “Surface preparation and characterization of indium tin oxide substrates for organic electroluminescent devices,” Appl. Phys., A Mater. Sci. Process. 68(4), 447–450 (1999).
[CrossRef]

Appl. Surf. Sci.

S. Zhan, X. Ying-Ge, L. Xia, and Y. Tao, “A novel hole-blocking layer NaF between the α-naphthylphenyliphenyl diamine and ITO,” Appl. Surf. Sci. 253(9), 4374–4376 (2007).
[CrossRef]

Chem. Phys. Lett.

J. S. Kim, P. K. H. Ho, D. S. Thomas, R. H. Friend, F. Cacialli, G. W. Bao, and S. F. Y. Li, “X-ray photoelectron spectroscopy of surface-treated indium-tin oxide thin films,” Chem. Phys. Lett. 315(5–6), 307–312 (1999).
[CrossRef]

J. Alloy. Comp.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, M.-R. Yang, and Z.-L. Tseng, “Enhancement of hole-injection and power efficiency of organic light emitting devices using an ultra-thin ZnO buffer layer,” J. Alloy. Comp. 479(1–2), 520–524 (2009).
[CrossRef]

J. Appl. Phys.

J. S. Kim, R. H. Friend, and F. Cacialli, “Surface energy and polarity of treated indium–tin–oxide anodes for polymer light-emitting diodes studied by contact-angle measurements,” J. Appl. Phys. 86(5), 2774–2778 (1999).
[CrossRef]

H. You, Y. Dai, Z. Zhang, and D. Ma, “Improved performances of organic light-emitting diodes with metal oxide as anode buffer,” J. Appl. Phys. 101(2), 026105 (2007).
[CrossRef]

M. G. Mason, L. S. Hung, C. W. Tang, S. T. Lee, K. W. Wong, and M. Wang, “Characterization of treated indium–tin–oxide surfaces used in electroluminescent devices,” J. Appl. Phys. 86(3), 1688–1692 (1999).
[CrossRef]

C. W. Tang, S. A. VanSlyke, and C. H. Chen, “Electroluminescence of doped organic thin films,” J. Appl. Phys. 65(9), 3610–3616 (1989).
[CrossRef]

J. Electrochem. Soc.

H.-H. Huang, S.-Y. Chu, P.-C. Kao, Y.-C. Chen, and R.-C. Chang, “Improved hole-injection and power efficiency of organic light-emitting diodes using an ultrathin Li-doped ZnO buffer layer,” J. Electrochem. Soc. 154(3), J105–J108 (2007).
[CrossRef]

Mater. Lett.

Z. Z. You, “Combined AFM, XPS, and contact angle studies on treated indium-tin-oxide films for organic light-emitting devices,” Mater. Lett. 61(18), 3809–3814 (2007).
[CrossRef]

Surf. Coat. Tech.

C. H. Yi, C. H. Jeong, Y. H. Lee, Y. W. Ko, and G. Y. Yeom, “Oxide surface cleaning by an atmospheric pressure plasma,” Surf. Coat. Tech. 177–178, 711–715 (2004).
[CrossRef]

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 (4)

Fig. 1
Fig. 1

(a) Current density-voltage (b) luminance-voltage characteristics for OLEDs with a NaF ultra-thin buffer layer of various thicknesses (c) current density-voltage characteristics of the hole-only devices.

Fig. 2
Fig. 2

(a) Ultraviolet photoelectron spectroscopy results of pristine NaF and UV-ozone treated NaF layers deposited on an ITO substrate; (b) Schematic energy band diagram.

Fig. 3
Fig. 3

(a) Surface energy and (b) surface polarity of ITO substrate and NaF-covered ITO substrate.

Fig. 4
Fig. 4

Na 1s X-ray photoelectron spectra for NaF film deposited on ITO substrate before and after UV-ozone treatment.

Tables (3)

Tables Icon

Table 1 Surface Tension Components of Test Liquids a

Tables Icon

Table 2 Some selected properties of buffer layers coated onto ITO and the opto–electronic performances of OLEDs.

Tables Icon

Table 3 Contact angles of H2O and CH2I2 on ITO, NaF/ITO and UV-ozone treated NaF/ITO

Equations (1)

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

γ L . ( 1 + cos θ ) = 2 ( γ S p . γ L p ) 1 / 2 + 2 ( γ S d . γ L d ) 1 / 2 ,

Metrics