Oxadiazoles and phenylquinoxalines as electron transport materials

The synthesis of a number of star-shaped oxadiazoles and phenylquinoxalines is described. These low molar mass compounds are able to form stable glasses with glass-transition temperatures up to 248 °C. The materials have been tested as electron transport layers in light-emitting devices (LEDs) together with poly(1,4-phenylene vinylene) (PPV). The two-layer LEDs show an improved quantum yield and brightness compared to PPV-monolayer LEDs.