Lithium-aluminum contacts for organic light-emitting devices

Organic light-emitting devices have been prepared with multilayer Al-Li-Al cathodes in an ultrahigh vacuum molecular beam deposition system. The optimum device characteristics are obtained when there is a single Al layer separating the Li layer from the organic materials. Ab initio molecular dynamics calculations of the AI-LI interaction clarify the role of Al as a blocking layer to Li diffusion into the organic films as well as the behavior of the device when the thickness of this Al interfacial layer is changed. (C) 1997 American Institute of Physics.