Electroluminescent Diodes from Complementary Discotic Benzoperylenes

Unequal brothers: Benzoperylene carboxylic acid derivatives with flexible chains not only form charge-transporting columnar liquid crystals (see graphic), their charge-transport properties can also be tuned to be either of n- or of p-type: relatively minor changes in the substitution pattern yield different materials that are complementary enough to form red-fluorescent charge-transfer complexes and p–n junction electronic devices.