DOI QR코드

DOI QR Code

교류 음 전압에 따른 형광 OLED의 전계 발광 특성

Electroluminescent Characteristics of Fluorescent OLED with Alternating Current Negative Voltage

  • Seo, Jung-Hyun (Department of Advanced Materials Science & Engineering, Daejin University) ;
  • Yang, Jae-Woong (Department of Advanced Materials Science & Engineering, Daejin University) ;
  • Paek, Kyeong-Kap (Department of Electronic Engineering, Daejin University) ;
  • Ju, Sung-Hoo (Department of Advanced Materials Science & Engineering, Daejin University)
  • 투고 : 2018.06.08
  • 심사 : 2019.03.24
  • 발행 : 2019.04.30

초록

To study the characteristics of AC driven OLED, we fabricated the fluorescent OLEDs and analyzed the electroluminescence characteristics of OLEDs with AC negative voltage. The luminance and the current density of the OLED decreased, and the number and size of the dark spots increased in proportion to the duration time and level of the applied AC negative voltage. The current efficiency of the OLED was improved when high AC negative voltage was applied within a short time. When the AC negative voltage of 10 V was applied for 1 minute, the efficiency was improved by 12.4%. Also, the degradation of luminance and current efficiency due to the duration of light emission was improved in the case of OLED applied for 1 minute with 10 V AC negative voltage. These are expected as a result of the improvement of the leakage current characteristics by eliminating the short-circuit region formed by the defect of the OLED at the AC negative high voltage. As a result, the continuous application of AC negative voltage reduced the luminance and the current density of OLED, but the temporary application of AC negative voltage with the proper time and voltage could improve the efficiency and lifetime of OLED.

키워드

PMGHBJ_2019_v52n2_72_f0001.png 이미지

Fig. 1. Structure of fluorescent OLED.

PMGHBJ_2019_v52n2_72_f0002.png 이미지

Fig. 2. AC negative voltage supply circuit board for OLED (a) schematic diagram, (b) board image.

PMGHBJ_2019_v52n2_72_f0003.png 이미지

Fig. 3. Current density and luminance of OLED with AC negative voltage application time

PMGHBJ_2019_v52n2_72_f0004.png 이미지

Fig. 4. Light emitting image of OLED with AC negative voltage application time.

PMGHBJ_2019_v52n2_72_f0005.png 이미지

Fig. 5. Current efficiency of OLED with AC negative voltage application time.

PMGHBJ_2019_v52n2_72_f0006.png 이미지

Fig. 6. Characteristics of OLED with reverse aging. (a) luminance, (b) current efficiency.

참고문헌

  1. C.W. Tang, S.A. Vanslyke, Organic electroluminescent diodes, Appl. Phys. Lett., 51 (1987) 913-915. https://doi.org/10.1063/1.98799
  2. J. Kido, M. Kimura, and K. Nagai, Multilayer white light-emitting organic electroluminescent device, Science., 267 (1995) 1332-1334. https://doi.org/10.1126/science.267.5202.1332
  3. T. Tsuboi, H. Murayama, S. J. Yeh, and C. T. Chen, Energy transfer between organic fluorescent CBP host and blue phosphorescent FIrpic and FIrN4 guests, Opt. Mater., 29 (2007) 1299-1304. https://doi.org/10.1016/j.optmat.2006.06.005
  4. Hyun-Dong Chun, Hyunseok Na, and Sung-Hoo Ju, Emission Properties of White Organic Light-Emitting Diodes with Blue Emitting Layer, J. KIEEME., 26 (2013) 451-456.
  5. J. H. Seo, J. H. Kim, and S. H. Ju, Emission Characteristics of Fluorescent OLED with Alternating Current Power Source Driving Method, J. KIEEME., 27 (2014) 104-109.
  6. J. H. Seo, S. H. Ju, Electroluminaescent Characteristics of Fluorescent OLED with Alternating Current Forward Bias, J. Korean Inst. Surf. Eng., 50 (2017) 398-404. https://doi.org/10.5695/JKISE.2017.50.5.398
  7. P. E. Burrows, V. Bulovic, S. R. Forrest, L. S. Sapochak, D. M. McCarty, and M. E. Thompson, Reliability and degradation of organic light emitting devices, Appl. Phys. Lett., 65 (1994) 2922. https://doi.org/10.1063/1.112532
  8. S. F. Lim, W. W. Wang and S. J. chua, Degradation of organic light-emitting devices due to formation and growth of dark spots, J. Materials science and engineering., 22, (2001) 154-159.
  9. P. E. Burrows, V. Bulovic, S. R. Forrest, L. S. Sapochak, D. M. McCarty, and M. E. Thompson, Reliablity and degradation of organic light emitting devices, Appl. Phys. Lett., 65 (1994) 2922-2924. https://doi.org/10.1063/1.112532
  10. M. Matsumura and Y. Jinde, Voltage dependance of light-emitting zone in aluminumhydroxyquinoline layers of organic heterojunction el devices, IEEE Trans. Electron Devices., 44, (1997) 1229-1233. https://doi.org/10.1109/16.605459
  11. C. W. Tang, An overview of organic electroluminescent materials and devices, J. of the SID., 5, (1997) 11-14.