New stylbene-based arylamines with dehydroabietic acid methyl ester moieties for organic light-emitting diodes

New triarylamines possessing a dehydroabietic acid methyl ester moiety and a stylbene substituent were prepared and tested as hole-transporting materials in light-emitting diodes, LEDs, with Alq3 as an emissive material. LEDs based on one of these new amines show similar performance to those where TPD, processed from solution, is used as hole-transporting material. In addition, while TPD films tend to crystallise upon storage at room temperature, the films of the new amines do not appear to crystallise under similar conditions. The stabilisation of an amorphous morphology is attributed to the presence of the bulky dehydroabietic acid methyl ester moiety, although it appears to reduce hole mobility.