Tunable Exciton Dissociation at the Organic/Metal Electrode Interface

Understanding of the dynamic optoelectronic processes at the organic/metal electrode interface is crucial to the interface engineering of organic electronics. Here we present the systematic studies of exciton dissociation of p-type organic semiconductor at the organic/Ag interface. The interfacial dissociation of photogenerated excitons at the N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB)/Ag interface was systematically investigated using the transient photovoltage technique as a proof-of-concept. The results indicate that two types of exciton dissociation—transfer of either electrons or holes to the metal electrode—coexist at the organic/metal electrode interface. This conclusion is further confirmed by two additional experiments—the current response of the NPB/Ag interface to light illumination under constant biases and the successive light current–voltage measurements under constant illumination. Moreover, the proportion of two types of dissociations was found to be tunable upon ...