Low-temperature scanning tunneling microscopy/ultraviolet photoelectron spectroscopy investigation of two-dimensional crystallization of C60: pentacence binary system on Ag(111)

Atomic scale investigation of temperature-dependent two-dimensional (2 D) crystallization processes of fullerene-C-60 on pentacene-covered Ag(111) surface has been carried out by in situ low-temperature scanning tunneling microscopy (LT-STM) experiments. To evaluate the effect of molecule-substrate interfacial interactions on the 2 D crystallization of C-60: pentacene binary system, we also carried out the same self-assembly experiments of C-60 on monolayer pentacene covered graphite substrate. It is revealed that temperature-dependent structural transition of various ordered C-60 nanoassemblies is strongly influenced by the molecule-Ag(111) interfacial interactions, and further mediated by the weak C-60-pentacene intermolecular interactions. In situ ultraviolet photoelectron spectroscopy (UPS) has been used to evaluate the nature of the intermolecular interactions between C-60 and pentacene films. (C) 2012 American Institute of Physics. [doi:10.1063/1.3679573]