Twin derivatives containing two 9-alkylcarbazol-3-yl fragments as new electro-active materials for organic light-emitting diodes

• Carbazole base twin derivatives have been synthesized and characterized.
• The compounds are efficient hole transporting materials.
• OLEDs using one the materials demonstrated maximum brightness of 6000 cd/m2.
• Maximum OLED efficiency was about 2.9 cd/A.

Twin derivatives with two 9-alkylcarbazol-3-yl fragments were synthesized by the multi-step synthetic rout. The materials were characterized by differential scanning calorimetry and electron photoemission technique. Some of the electro-active derivatives were tested as solution processed hole transporting layers in organic light-emitting diodes with Alq3 as the emitter. The electroluminescent devices exhibited promising overall performance with a maximal photometric efficiency of about 2.9 cd/A and maximum brightness of 6000 cd/m2.