We studied electron injection form Al cathode into the tris(8-hydroxyquinoline)aluminum (Alq₃). When a thin CsCl layer is inserted between Alq₃ and Al, a substantial enhancement in electron injection is observed. The results show that the device with the cathode containing the ultrathin CsCl layer has a higher brightness and electroluminescent efficiency than the device without this layer. Further, organic light-emitting devices (OLEDs) based on tris-(8-hydroxyquinoline)aluminum using a trilayer of CsCl/LiF/Al as cathodes have been fabricated. The results show that the device with the cathode containing 0.5 nm CsCl layer and 1.0 nm LiF layer has a higher brightness and electroluminescent efficiency than that of the device with LiF/Al or CsCl/Al cathodes. The maximum EL efficiency of the CsCl/LiF/Al cathode device is 3.41 cd/A, which is higher than the 2.74 cd/A of the LiF/Al device and 2.49 cd/A of the CsCl/Al device.

Date Published: 12 May 2004
PDF: 5 pages
Proc. SPIE 5280, Materials, Active Devices, and Optical Amplifiers, (12 May 2004); doi: 10.1117/12.520380

Published in SPIE Proceedings Vol. 5280:
Materials, Active Devices, and Optical Amplifiers
Connie J. Chang-Hasnain; Dexiu Huang; Yoshiaki Nakano; Xiaomin Ren, Editor(s)