Summary: We have designed and synthesized novel diphenylamine‐substituted phenylazomethine dendrimers (DP‐Gn, n = 1, 2) as hole‐transport materials for organic light‐emitting diodes (OLEDs). These dendrimers similar to phenylazomethine dendrimers showed a stepwise metal complexation with metal ions. They have good multi‐redox properties attributed to the terminal amine moieties and excellent thermal stabilities. Double layer EL devices utilizing the dendrimers as a hole‐transport material and Alq3 as the emitting and electron transport materials were fabricated. The EL performances of the devices increased with higher dendrimer generations. Moreover, by using the metal ion (0.5 equiv. SnCl2)‐complexed DP‐G2 dendrimers, the luminance and EL efficiency of the devices were drastically increased by more than double and over 30%, respectively. These metal complexable phenylazomethine dendrimers are novel and promising materials for highly efficient OLEDs.
Structure of the diphenylamine‐substituted phenylazomethine dendrimer DP‐G2.
