Enhanced Brightness and Efficiency in Organic Light-Emitting Devices Using an LiF-Doped Electron-injecting Layer with Aluminium Cathode

Organic light-emitting devices (OLEDs) with enhanced brightness and efficiency were developed using an LiF-doped organic layer as an electron-injecting layer besides the aluminium cathode. The typical device structure is glass substrate/indium-tin-oxide/N, N'-bis (3-methyphenyl)-N, N'-diphenylbenzidize/8-tris-hydroxyquinoline aluminium (Alq₃)/LiF-doped Alq₃/Al. An optimized device with an LiF-doped Alq₃ layer showed brightness over 15300 cd/m², while the device without the LiF-doped Alq₃ layer exhibited only 3200 cd/m², also, the luminance efficiency of the former was 4-5 times as that of the latter. This is another way to improve the OLEDs performance, especially in applications of OLEDs with a large active area.