Reduced angular dependence of the emission from tris(8-hydroxyquinoline) aluminum based microcavity

Organic microcavity light emitting diodes typically exhibit a significant blue shift of the emission wavelength with the viewing angle. In this work, we demonstrate significant reduction of the emission angular dependence of a microcavity device consisting of two organic layers, N,N′-di(naphthalene-1-yl)-N,N′-diphenylbenzidine (NPB) as a hole transport layer and tris(8-hydroxyquinoline) (Alq) as emitting layer, between two metal mirrors. The reduction of the angular dependence of the emission was achieved by optimizing the thickness of the layers within the device. The reasons for the reduced emission wavelength shift with the viewing angle are discussed.