Lithium-Aluminum Cathodes for Organic Light-Emitting Devices

We have examined the performance characteristics of organic light-emitting devices prepared with multilayer Al-Li-Al cathodes in an ultrahigh vacuum molecular beam deposition system. The optimum device characteristics
are obtained when one or two atomic layers of Al are deposited on the organic materials prior to Li deposition.
Ab initio molecular dynamics calculations of the Li-Al interaction as well as the interaction of Li and Al with Alq(3) clarify the role of Al in preventing Li diffusion into the organic films and the electro-optical behavior of the device as the thickness of the Al interfacial layer is changed.