Spacial distribution of electroluminescence from oriented phenylenevinylene oligomer Langmuir-Blodgett film

An organic electroluminescent (EL) device with a well-defined molecular orientation was prepared by using a phenylenevinylene oligomer (MOPV) Langmuir-Blodgett (LB) film. The device consisted of an oxadiazole electron-transporting layer, a diamine hole-transporting layer and an emissive layer of the MOPV LB film where MOPV molecules oriented nearly normal to the film plane. Because of the normal orientation of MOPV molecules in the emissive layer, the device exhibited a quite different spacial distribution of EL intensity from the Lambertian distribution; EL intensity has a maximum at a viewing angle of about 40 ° to the normal direction to the device surface.