Anion adsorption driving 2D crystallization of C60 at the ionic liquid [bmim][PF6]/Au(1 1 1) interface

Abstract The two-dimensional (2D) crystallization of C 60 , driven by the anion adsorption, at the [bmim][PF 6 ]/Au(1 1 1) interface has been investigated by in situ scanning tunneling microscopy (STM). It is found that although a number of small ordered domains of C 60 exist in air, they will gradually merge into some big ones in [bmim][PF 6 ]. The formation of a high-quality epitaxial C 60 film is attributed to the slow replacement of C 60 by the PF 6 adsorption and the high mobility of C 60 on PF 6 /Au(1 1 1), i.e., a competitive adsorption–desorption process between C 60 and PF 6 . Such strategy could be used to prepare epitaxial films of functional molecules.