Abstract
The influence of pulse current (PC) versus direct current (DC) driving mode on the operation stability of organic light-emitting diodes, which based on N,N’-di(naphthalene-1-yl)-N,N’-diphenylbenzidine (NPB) and tris(8-hydroxyquinoline) aluminum (Alq3) without hole-injection layer (HIL) and with two different HILs, was investigated. The two HILs were copper phthalocyanine (CuPc) and 4,4’,4’’-tris(3-methylphenylphenylamino) triphenylamine (m-MDTATA) respectively. It was found that the lifetimes of devices without HIL and with CuPc, m-MTDATA as the HIL under PC driving mode were 2, 1.5 and 0.9 times longer than that under DC driving mode respectively. Analysis of electrical characteristics of corresponding hole-only devices showed that the injected holes into device were greatly reduced by inserting m-MTDATA layer compared to the two other devices, and indicated that different ratios of the injected electrons / holes were obtained in these devices, which play a dominant role in the influence of driving mode on the operation stability.
Keywords
OLED, Stability, Driving mode, Electrons/holes.
Citation
W. ZHANG, Z. WU, X. ZHANG, S. LIANG, B. JIAO, X. HOU, Influence of driving mode on the operation stability of organic light-emitting diodes, Optoelectronics and Advanced Materials - Rapid Communications, 4, 9, September 2010, pp.1379-1383 (2010).
Submitted at: April 14, 2010
Accepted at: Sept. 15, 2010