Energy level diagrams of C60/pentacene/Au and pentacene/C60/Au

The electronic structures of pentacene and C60 interfaces were investigated using ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). The magnitudes of measured interface dipole were 0.11 eV and 0.07 eV for the C60 deposited on pentacene (C60/pentacene) and the pentacene deposited on C60 (pentacene/C60), respectively. The obtained C 1s spectra on these samples show that no significant chemical bonds at the interface. The offsets of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) at the C60-pentacene interface were 1.29 eV and 0.89 eV for C60/pentacene/Au, while for pentacene/C60/Au they were 1.5 eV and 1.1 eV. In this paper we present the complete energy level diagrams of C60/pentacene/Au and pentacene/C60/Au.