Control of spontaneous emission using microcavity structures in organic electroluminescent devices

Summary form only given. Control of spontaneous emission in organic elactroluminescant devices by using planar microcavity structures is demonstrated. Multilayer-dye electroluminescent devices which were composed of a hole transport layer, an emission layer and an electron transport layer were used. Semi-transparent metal films or an indium-tin-oxide transparent layer with a dielectric stack mirror as an anode and a highly reflective MgAg arroy film as a cathode costituted the Fabry-Perot cavity with spacings of the order of the wavelength of emission light. Firstly, the changes of emission lifetimes with the change of cavity-sizes, which evidenced the existence of the effect of confined radiation field in microcavities, were demonstrated. Secondly the change of both emission spectra and spacial distribution of emission patterns in electroluminescent devices with microcavity structures were studied. Finally, the realization of strongly-directed emission using the simple Fabry-Perot type electroluminescent devices with Europium-complex as an emission layer was demonstrated.