Tris-(8-hydroxyquinoline)aluminum (Alq 3), which is typically used as an electron transport material for organic light-emitting devices (OLEDs), was used in this study for OLED anode modification. The electronic structure at the indium tin oxide (ITO)/organic interface for improvement of carrier injection was studied using ultraviolet photoelectron spectroscopy. The interfacial analysis reveals that the barrier height at the ITO/organic interface can be varied from ∼ 0.6-1.08 eV. It is demonstrated that the barrier for hole injection from an ITO anode to a hole transporting layer can be engineered by inserting an ultrathin interlayer of Alq 3, a few nanometers thick. The presence of an Alq 3 interlayer is shown to improve the current balance, leading to an enhancement in the electroluminecent efficiency and operational stability of OLEDs.
Scopus Subject Areas
- Physics and Astronomy (miscellaneous)