NOVEL ORGANIC EL ELEMENT WITH HEIGHTENED LUMINESCENT EFFICIENCY

摘要

A novel organic electroluminescent element (organic EL element) is provided. The organic EL element comprises two electrodes disposed so as to face each other and one or more organic films interposed therebetween, and is characterized in that at least one of the organic films comprises a luminescent layer comprising a host (which is an aromatic compound or a complex compound) and a dopant (which is a complex compound) and that the amount of the dopant complex compound, in terms of parts by weight per 100 parts by weight of the total amount of the host and dopant (hereinafter referred to as dopant concentration), is not even throughout the layer and the layer has a dopant concentration gradient so that the dopant concentration is maximum in a part close to one electrode and is minimum in a part close to the other electrode.