Enhanced Brightness and Efficiency in Single-Layer White Polymer Light-Emitting Diodes (PLEDs)

Abstract:

In this paper, the improvements in luminance and efficiency have been demonstrated in a white polymer light-emitting device (PLED) with the structure of ITO/ poly (N-vinylcarbazole) (PVK): 1,1,4,4- tetraphenyl-1,3-butadiene (TPB):5,6,11,12-tetrapheny lanpthacene (rubrene) /LiF(1 nm)/Ca(10 nm)/Al(100 nm). The luminance of the white PLED is up to 4940 cd/m2 at 17 V. The current efficiency and Commission Internationale d’Eclairage (CIE) coordinates is 1.66 cd/A and (0.325, 0.326), respectively. The enhancement of the luminance and efficiency can be attributed to an improved hole-injection ability and balance carrier recombination through two ways: (1) enhancing the hole-injection from ITO by using O2 plasma treatment, and (2) balance the recombination of hole and electron by produce a buffer layer with σ-bonded segments of polymer between the ITO and the polymer layer. Besides, orange-emitting rubrene provides that direct recombination of holes and electrons occurred on the dopant molecules and trapping significantly enhanced the luminance and efficiency.

• Periodical: Key Engineering Materials (Volumes 434-435)
• Pages: 429-433
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.434-435.429
• Online since: March 2010
• Authors: Dei Wei Chou, Kan Lin Chen, Chien Jung Huang, Chern Hwa Chen, Wen Ray Chen, Teen Hang Meen, Ke Shiang Shiau
• Keywords: Electroluminescence, Polymer Light-Emitting Device (PLED)

References

[1] E. Han, l. Bo, Y. Niidome and M. Fujihira: Chen. Lett. (1994), p.969.

[2] D. Troadec, G. Veriot, R. Antony and A. Molition: Synthetic Met. Vol. 124 (2001), p.49.

[3] Z. Zhilin, J. Xueyin and X. Shaohong: Thin Solid Films Vol. 363 (2000), p.61.

DOI: 10.1016/s0040-6090(99)00984-0

[4] W. S. Bacsa, M. Schaer and L. Zuppiroli: J. Appl. Phys. Vol. 84 (1998), p.5733.

[5] L. Zugang and H. Nazre: Synth. Met. Vol. 111 (2000), p.47.

[6] J. Kido, M. Kohda and K. Nagai: Appl. Phys. Lett. Vol. 61 (1992), p.761.

[7] J. Kido, H. Shionoya and K. Nagai: Appl. Phys. Lett. Vol. 67 (1995), p.2281.

[8] F. Li, H. Tang, J. Shinar and S. Z. Weisz: Appl. Phys. Lett. Vol. 70 (1997), p.2741.

[9] C. C. Wu, C. I . Wu, J. C. Strum and A. Lahn: Appl. Phys. Lett. Vol. 70 (1997), p.1348.

[10] I. M. Chan, W. C Cheng and F. C. Hong: Appl. Phys. Lett. Vol. 80 (2002), p.13.

[11] J. Liu, Y. Shi, L. Ma and Y. Yang: J. Appl. Phys. Vol. 88 (2000), p.605.

[12] Y. Shi, J. Liu and Y. Yang: J. Appl. Phys. Vol. 87 (2000), p.4254.

[13] M. Uchida, C. Adachi, T. Koyama and Y. Taniguchi: J. Appl. Phys. Vol. 86, (1999), p.1680.