LiF as an n-dopant in tris(8-hydroxyquinoline) aluminum thin films

Facile non-alkaline n-doping of Alq(3) with LiF is achieved by co-evaporation. Optimal doping not only leads to enhanced device currents and conductivity, but also changes the very nature of carrier injection and transport. Using this scheme, efficient electron injection is achieved without using low-work-function cathodes. A doped transport layer (see figure) in OLEDs leads to balanced injection and transport of charge carriers and results in excellent device performance.