Low Voltage Organic Light-emitting Devices with Step Barrier Layer
The electron injection transportation in OLEDs were improved by using a Gaq layer between Alq ( or Bphen) and TBADN as step barrier. Since the LUMO (Lowest Unoccupied Molecular Orbital) of Gaq (2.9 eV) lies in between that of Alq (3.1 eV)(or Bphen(3.0eV)) and TBADN (2.8eV), step barrier from Alq (or BPhen) though Gaq to TBADN can be formed. The experimental results indicate that; The J-V characteristics of both the electron only and the complete devices show the increase of the current density in devices with step barrier compared with the devices without step barrier. For electron only devices, the driving voltage at the current density of 20 mA/cm2 were reduced from 7.9 V to 4.9 V for devices with Alq, and from 4.2 V to 3.1 V for devices with Bphen respectively owing to the introduce of step barrier. For the complete devices, after Gaq step barrier was introduced, at 20 mA/cm2, the driving voltage were reduced from 7 V to 5. 8 V for devices with Alq and from 6.2 V to 5.1 V for devices widi Bphen. When step barrier was introduced, the luminance at 200 mA/cm2 were increased from 1 684 cd/m2 to 2 736 cd/m2 for device with Alq, and from 1 026 cd/m2 to 2466 cd/m2 for devices with BPhen respectively. The phenomena were explained by using tunnel theory.
OLEDS Low Voltage Tunnel Theory
W. Xu M. A. Khan X. Y. Jiang Z. L. Zhang W. Q. Zhu
Key Laboratory of Advanced Display and System Application, Ministry of Education,Shanghai University, Shanghai 200072, China;Department of Materials Science, Shanghai University, Jiading Campus,Shanghai 201800, China
国际会议
上海
英文
1360-1363
2007-03-12（万方平台首次上网日期，不代表论文的发表时间）