Spontaneous electron transfer from C60 to Au ions: oxidation of C60 and hole doping

Abstract

Spontaneous oxidation of C60 by Au ions was observed. When C60 was guided to make contacts with Au3+ ions in aqueous HAuCl4 solution, electrons were spontaneously transferred from C60 to Au3+ ions, resulting in hole (h+) doped C60 cations and Au nanoparticles on a C60 layer. This spontaneous electron transfer occurs due to the galvanic displacement from C60 to Au3+ ions owing to the energy difference between Fermi energy level of C60 (−4.7 eV) and standard reduction potential of Au3+ ion (+1.002 V). The oxidation of C60 as well as the consequent formation of reduced Au nanoparticles were confirmed by atomic force microscopy, X-ray photoelectron spectroscopy, and electrochemistry. The switch of majority charge carrier type from electron to hole and its stability in air were also confirmed by monitoring I–Vg characteristic curves of a C60 field effect transistor (FET) device before and after the reaction with Au3+ ions.