Blue-Emitting Anthracenes with End-Capping Diarylamines

A new series of 2- tert -butyl-9,10-bis(bromoaryl)anthracenes have been synthesized from 2- tert -butyl-9,10-anthraquinone. Palladium-catalyzed C−N bond formation between these bromo compounds and diarylamines provides stable 2- tert -butyl-9,10-diarylanthracenes containing two peripheral diarylamines ( anth ). They possess high thermal decomposition temperature ( T d > 450 °C) and form a stable glass ( T g > 130 °C). Furthermore, they are fluorescent in the blue region with moderate to good quantum efficiencies. Two types of light-emitting diodes (LED) were constructed from anth, (I) ITO/ anth /TPBI/Mg:Ag and (II) ITO/ anth /Alq 3 /Mg:Ag, where TPBI and Alq 3 are 1,3,5-tris( N -phenylbenzimidazol-2-yl)benzene and tris(8-hydroxyquinolinato)aluminum, respectively. In type I devices, the anth function as the hole-transporting and emitting material. In type II devices, emission from Alq 3 is observed. Several blue-light-emitting type I devices exhibit good maximum brightness and physical performance. The relation between the energy levels of the anth and the performance of the light-emitting diode is discussed.