Formation of perfect ohmic contact at indium tin oxide/N,N′- di(naphthalene-1-yl)-N,N′-diphenyl-benzidine interface using ReO 3

Abstract

A perfect ohmic contact is formed at the interface of indium tin oxide (ITO) and N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB) using ReO 3 as the interfacial layer. The hole injection efficiency is close to 100% at the interface, which is much higher than those for interfacial layers of 1,4,5,8,9,11-hexaazatripheylene hexacarbonitrile (HAT-CN) and MoO 3. Interestingly, the ReO 3 and MoO 3 interfacial layers result in the same hole injection barrier, ≈0.4â€...eV, to NPB, indicating that the Fermi level is pinned to the NPB polaron energy level. However, a significant difference is observed in the generated charge density in the NPB layer near the interfacial layer/NPB interface, indicating that charge generation at the interface plays an important role in forming the ohmic contact.