Porous alumina based cathode for organic light-emitting devices

We propose a new cathode for organic light-emitting devices based on anodic porous alumina films. For this purpose usual and modified porous alumina and structured aluminium with removed porous alumina layer can be used. The usage of porous alumina cathode results in more inhomogeneous electric field and, as a consequence, more intensive auto electron emission and cathode efficiency. Owing to extended surface this matrix also gives the possibility to reach higher luminophor concentration without noticeable luminescence quenching. Organic electroluminescent devices of this type are easily produced and can be more efficient and stable as compared with usual layered structures. An intensive secondary electron emission is observed after irradiating of activated alumina matrix by an electron beam. We developed one of the proposed porous alumina cathode based organic electroluminescence structure doped with amorphous naphthalimide derivative. A bright electroluminescence of naphthalimide in such a structure was observed for the first time. The ways of the further development of this structure are pointed out.