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 (Alq(3)) /LiF-doped Alq(3)/Al. An optimized device with an LiF-doped Alq(3) layer showed brightness over 15300 cd/m(2), while the device without the LiF-doped Alq(3) layer exhibited only 3200 cd/m(2), 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.