Korean Journal of Materials Research (한국재료학회지)

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

DOI QR Code

Impedance Characteristics of Fluorescent OLED with Device Structure

소자 구조에 따른 형광 OLED의 Impedance 특성

  • Kong, Do-Hoon (Department of Advanced Materials Science & Engineering, Daejin University) ;
  • Ju, Sung-Hoo (Department of Advanced Materials Science & Engineering, Daejin University)
  • Received : 2017.07.24
  • Accepted : 2017.11.14
  • Published : 2018.01.27
Download PDF
⟨ Previous Next ⟩

Abstract

To study the impedance characteristics of a fluorescent OLED according to the device structure, we fabricated Device 1 using ITO / NPB / $Alq_3$ / Liq / Al, Device 2 using ITO / 2-TNATA / NPB / $Alq_3$ / Liq / Al, and Device 3 using ITO / 2-TNATA / NPB / SH-1:BD / $Alq_3$ / Liq / Al. The current density and luminance decreased with an increasing number of layers of the organic thin films in the order of Device 1, 2, 3, whereas the current efficiency increased. From the Cole-Cole plot at a driving voltage of 6 V, the maximum impedance values of Devices 1, 2, and 3 were respectively 51, 108, and $160{\Omega}$ just after device fabrication. An increase in the impedance maximum value is a phenomenon caused by the charge mobility and the resistance between interfaces. With the elapse of time after the device fabrication, the shape of the Cole-Cole plot changed to a form similar to 0 or a lower voltage due to the degradation of the device. As a result, we were able to see that an impedance change in an OLED reflects the characteristics of the degradation and the layer.

Keywords

References

  1. Qi Zhang, Xizowen Zhang and Bin Wei, Optik, 126, 1595 (2015). https://doi.org/10.1016/j.ijleo.2015.05.091
  2. E. K. Nam, H. Park, K. Park, M. R. Moon, S. Sohn, D. Jung, J, Yi, H, Chae and H. Kim, Thin Solid Films, 517, 4131 (2009).
  3. X. W. Zhang, B. J. Mo, L. M. Liu, H. H. Wang, D. T. Chang, J. W. Xu, H. Wang and B. Wei, Curr. Appl. Phys., 14, 1460 (2014). https://doi.org/10.1016/j.cap.2014.08.021
  4. G. Chauhan, R. Srivastava, P. Tyagi, A. Kumar, P. C. Srivastava and M. N. Kamalasanan, Synth. Met., 160, 1422 (2010). https://doi.org/10.1016/j.synthmet.2010.04.022
  5. Y. H. Park and Y. M. Kim, Curr. Appl. Phys., 13, 336 (2013). https://doi.org/10.1016/j.cap.2012.08.007
  6. S. Ishihara, H. Hase, T. Okachi and H. Naito, Org. Electron., 12, 1364 (2011). https://doi.org/10.1016/j.orgel.2011.05.004
  7. D. R. Evans, H. S. Kwak, D. J. Giesen, A. Goldberg, M. D. Halls and M. Oh-e, Org. Electron., 29, 50 (2016). https://doi.org/10.1016/j.orgel.2015.11.021
  8. G. Y. Kim, J. S. Oh, E.-H. Choi, G. S. Cho, S. O. Kang and J. W. Cho, J. Korean Vac. Soc., 11, 171 (2002).
  9. C.-S. Park, D.-H. Kong, J.-H. Kang, S.-H. Yun and S.-H. Ju, J. Korean Inst. Surf. Eng., 48, 115 (2015). https://doi.org/10.5695/JKISE.2015.48.3.115
  10. J.-H. Lee, J. Korean Inst. Electr. Electron. Mater. Eng., 17, 1341 (2004).
  11. J. Y. Lee, J.-Y. Park, S.-H. Min, K.-W. Lee and Y. G. Baek, Thin Solid Films, 515, 7726 (2007).
  12. H. Chen, C.-H. Gao, Z.-Q. Jiang, L. Zhang, L.-S. Cui, S.-J. Ji and L.-S. Liao, Dyes Pigments, 107, 15 (2014). https://doi.org/10.1016/j.dyepig.2014.03.006