The initial interface formation between Al and tris-(8-hydroquinoline) aluminum (Alq3) with LiF interlayer

The interface between Al and tris-(8-hydroquinoline) aluminum (Alq3) was studied using in situ medium energy ion scattering spectroscopy. We compared two interfaces of Al/LiF/Alq3 and Al/Alq3 with the elemental depth profile of each interface. The thin LiF changes the interfacial structures significantly; the excess Li in the LiF layer diffuses into Alq3 while F does not. In addition, the Al diffusion into the Alq3 layer during the initial stages of Al deposition is reduced significantly compared to the interface without the LiF interlayer. The LiF interlayer makes a more abrupt metal–organic interface, which would contribute to the efficiency and stability of the organic light-emitting device.