A method is provided to produce an opto-electronic device comprising a substrate, a first electrode layer, a second electrode layer of opposite polarity to said first electrode layer, any interlayers and, between said first and second electrode layers, a first functional material in interfacial contact with a second functional material, wherein the first functional material has the structure of a laterally porous film and the second functional material is a film disposed over and interpenetrating with the film of the first functional material.