Novel triarylamine dendrimers as a hole-transport material with a controlled metal-assembling function.

A series of phenylazomethine dendrimers with a triarylamine core (TPA-DPA) were synthesized by dehydration using TiCl4. The complexation of the fourth genereration (G4) TPA-DPA with SnCl2 proceeds in not a random but a stepwise fashion from the core to the terminal imines of the G4 dendrimer. The molecular size of TPA-DPA G4 is larger than that of DPA G4 in THF solution and has a rigid sphere structure like a globular protein. Organic light-emitting diodes (OLEDs) were fabricated, and the EL performances of the devices using the TPA-DPA-metal complexes as the hole-transport materials are drastically increased (ca. 20 times) by metal complexation.