Bridged-triarylamine starburst oligomers as hole transporting materials for electroluminescent devices

Two bridged-triphenylamine starburst molecules were designed and synthesized. Their electrochemical properties were studied in detail using cyclic voltammetry (CV) and square wave voltammetry (SWV) methods. The bridged molecular structure stabilizes the oxidative state and decreases the oxidation potentials, resulting in an increased HOMO energy level. Double-layer sandwich electroluminescence devices were fabricated. The bridged triphenylamine starburst 4 has shown significantly enhanced performance compared with the triphenylamine analog 3 and its ethenyl-linked derivative 6.