Contact issues in electroluminescent devices from ruthenium complexes

We report on the temporal evolution of the current, radiance and efficiency of electroluminescent devices based on films of [Ru(bpy)(3)](2+)(PF6-)(2) (bpy is 2,2(')-bipyridyl) with various electrodes. Under forward bias (with the bottom electrode wired as the anode) the device characteristics were independent of the electrodes used. The situation was different under reverse bias, where differences were observed in the steady-state as well as in the transient characteristics of devices with different electrodes. The origin of this asymmetry is discussed. (C) 2004 American Institute of Physics.