Aryl substituted 9-(2,2-diphenylvinyl)carbazoles as efficient materials for hole transporting layers of OLEDs

Phenyl or naphthyl substituted 9-(2,2-diphenylvinyl)carbazoles were synthesized by the multi-step synthetic route. The materials were examined by various techniques including thermogravimetry, differential scanning calorimetry, and electron photoemission technique. These derivatives were also tested as hole-transporting materials in bilayer OLEDs with Alq3 as the emitter. The devices exhibited promising overall performance with a turn-on voltage of 3.2 V, a maximal photometric efficiency of about 4.8 cd/A and maximum brightness of 12,400–13,100 cd/m2.