Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
권호 표지
DOI QR코드

DOI QR Code

Improving the Electrical and Optical Properties of Blue Polymer Light Emitting Diodes by Introducing TPBI Electron Transport Layer

TPBI 전자 수송층을 이용한 청색 고분자 유기발광다이오드의 전기·광학적 특성 향상

  • 공수철 (단국대학교 전자공학과) ;
  • 전창덕 (단국대학교 전자공학과) ;
  • 유재혁 (네패스 AP 그룹 반도체연구소) ;
  • 장호정 (단국대학교 전자공학과)
  • Received : 2010.04.15
  • Accepted : 2010.05.31
  • Published : 2010.06.27
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, we fabricated a polymer light emitting diode (PLED) and investigated its electrical and optical characteristics in order to examine the effects of the PFO [poly(9,9-dioctylfluorene-2-7-diyl) end capped with N,N-bis(4-methylphenyl)-4-aniline] concentrations in the emission layer (EML). The PFO polymer was dissolved in toluene ranging from 0.2 to 1.2 wt%, and then spin-coated. To verify the influence of the TPBI [2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)]electron transport layer, TPBI small molecules were deposited by thermal evaporation. The current density, luminance, wavelength and current efficiency characteristics of the prepared PLED devices with and without TPBI layer at various PFO concentrations were measured and compared. The luminance and current efficiency of the PLED devices without TPBI layer were increased, from 117 to $553\;cd/m^2$ and from 0.015 to 0.110 cd/A, as the PFO concentration increased from 0.2 to 1.0 wt%. For the PLED devices with TPBI layer, the luminance and current efficiency were $1724\;cd/m^2$ and 0.501 cd/A at 1.0 wt% PFO concentration. The CIE color coordinators of the PLED device with TPBI layer at 1.0 wt% PFO concentration showed a more pure blue color compared with the one without TPBI, and the CIE values varied from (x, y) = (0.21, 0.23) to (x, y) = (0.16, 0.11).

Keywords

References

  1. Y. Xu, J. Peng, Y. Mo, Q. Hoe and T. Cao, Appl. Phys. Lett., 86, 163502 (2005). https://doi.org/10.1063/1.1901824
  2. J. G. Jang, S. J. Shin, E. J. Kang, H. W. Kim, H. J. Chang,M. W. Oh, Y. S. Kim, J. Y. Lee, M. S. Gong and Y. K.Lee, Kor. J. Mater. Res., 16(4), 253 (2006). https://doi.org/10.3740/MRSK.2006.16.4.253
  3. B. W. D’Andrade, R. J. Holmes, S. R. Forrest, Adv. Mat.,16, 624 (2004). https://doi.org/10.1002/adma.200306670
  4. M. Mazzeo, D. Pisignano, F. Della Sala, J. Thompson,R. I. Blyth, G. Gigli, G. Sotgiu and G. Barbareiia, Appl. Phys. Lett., 82, 334 (2003). https://doi.org/10.1063/1.1531217
  5. S. C. Chang, J. Liu, J. Bharathan, Y. Yang, J. Onoharaand J. Kido, Adv. Mat., 11(9), 734 (1999). https://doi.org/10.1002/(SICI)1521-4095(199906)11:9<734::AID-ADMA734>3.0.CO;2-D
  6. D. H. Lee, J. S. Choi and S. M. Cho, Digest of Technical Paper of 7th IMID (EXCO, Deagu, Korea, August 2007)Vol. 7, P1-55, 694 (2007).
  7. A. Duggal, Advanced Technology Leader Electronics Materials Systems, General Electronic On the Web. Retrieved March 11th, 2008 from http://ge.geglobalresearch.com/blog/worlds-first-demonstration-of-roll-to-roll-processedoleds.
  8. W. G. Suh and D. G. Moon, J. KIEEME (in Korean),22(4), 323 (2009).
  9. W. K. Kim, H. S. Kim, H. K. Shin and J. G. Jang, Kor. J. Mater. Res., 19(5), 240 (2009) https://doi.org/10.3740/MRSK.2009.19.5.240
  10. W. C. H. Choy, K. N. Hui, H. H. Fong, Y. J. Liang andP. C. Chui, Thin Solid Films, 509, 193 (2006). https://doi.org/10.1016/j.tsf.2005.09.135
  11. C. Adacci, M. A. Baldo, M. E. Thompson and S. R.Forrest, J. Appl. Phys., 90(10), 5048 (2001). https://doi.org/10.1063/1.1409582
  12. M. Ben Khalifa, D. Vaufrey and J. Tardy, Org. Electron.,5, 187 (2004). https://doi.org/10.1016/j.orgel.2003.11.006
  13. J. Davenas, S. Besbes, H. Ben Ouada and M. Majdoub,Mater. Sci. Eng. C, 21, 259 (2002). https://doi.org/10.1016/S0928-4931(02)00077-2
  14. J. H. Burrorghes, D. D. C. Bradlye, A. R. Brown, R. N.Marks, K. Mackay, R. H. Friend, P. L. Burns and A. B.Holmes, Nature, 347, 539 (1990). https://doi.org/10.1038/347539a0
  15. A. O. Sevim and S. Mutlu, Org. Electron., 10, 18 (2009). https://doi.org/10.1016/j.orgel.2008.09.003
  16. H. S. Woo, B. S. Kim, C. G.. Kim, J. J. Oh, M. S. Kim,S. J. Park, T. W. Kwon, S. J. Cho, D. K. Park and S. H.Jin, J. Cryst. Growth, 288, 137 (2006). https://doi.org/10.1016/j.jcrysgro.2005.12.041
  17. J. Y. Lee, J. Information Display, 8(3), 1 (2007). https://doi.org/10.1080/15980316.2007.9652031
  18. S. C. Gong and H. J. Chang, Kor. J. Mater. Res., 19(6),313 (2009) https://doi.org/10.3740/MRSK.2009.19.6.313
  19. C. M. Yang, H. H. Liao, S. F. Horng, H. F. Meng, S. R.Tseng and C. S. Hsu, Synthetic Met., 158, 25 (2008). https://doi.org/10.1016/j.synthmet.2007.11.006
  20. P. I. Lee, S. L. C. Hsua and C. T. Chung, Synthetic Met.,156, 907 (2006). https://doi.org/10.1016/j.synthmet.2006.05.014
  21. I. M. Chan, F. C. N. Hong, Thin Solid film, 444, 254(2003). https://doi.org/10.1016/S0040-6090(03)01197-0
  22. K. S. Yang, B. S. Kim, D. S. Kim, H. K. Shin and Y. S.Kwon, Trans. KIEE, 54C(1), 8 (2005).
  23. Z. Zhao, J. H. Li, P. Lu and Y. Yang, Adv. Funct. Mat.,17, 2203 (2007). https://doi.org/10.1002/adfm.200700195
  24. V. I. Adamovich, S. R. Cordero, P. I. Djurovich, A.Tamayo, M. E. Thompson, B. W. D’Andrade and S. R.Forrest, Org. Electron., 4, 77 (2003). https://doi.org/10.1016/j.orgel.2003.08.003
  25. A. W. Grice, D. D. C. Bradley, M. T. Bernius, M.Inbasekaran, W. W. Wu and E. P. Woo, Appl. Phys. Lett.,73(5), 629 (1998). https://doi.org/10.1063/1.121878