Electronic structure and morphology of organic/metal/organic junctions

We have investigated the electronic structures and morphologies of two organic–metal–organic junctions, relevant for organic bistable devices, photovoltaics, and light emitting devices. Combined photoemission spectroscopy and scanning probe measurements found that in a 3,4,9,10 perylenetetracarboxylic dianhydride bis-benzimidazole (PTCBI)/Ag/Cu-phthalocyanine (CuPc) junction, Ag undergoes a chemical reaction with PTCBI leading to a discontinuous film of Ag clusters. In contrast, Au forms a continuous metal film in the PTCBI/Au/CuPc junction with no observable chemistry occurring. Photoemission spectroscopy suggests that both heterojunctions exhibit barrierless charge recombination leading to very similar functional behavior when integrated in device structures despite significant chemical and morphological differences.