Two-dimensional arrays of self-assembled gold and sulfur-containing fullerene nanoparticles

Two-dimensional (2D) arrays of gold nanoparticles with sulfur-containing fullerene nanoparticles were self-assembled through the formation of Au-S covalent bonds. Disulfide functional groups were introduced into the C-60 molecule by reacting propyl 2-aminoethyl disulfide with C60. The 2D arrays were formed at the interface of the aqueous phase of gold particles and organic phase of fullerene particles as a blue transparent film. Transmission electronic microscope images showed that the fullerene spacing between adjacent Au (similar to10 nm) particles was about 2.1 +/- 0.4 mn, which was consistent with the result of 2.18 nm by molecular molding calculations (MM+). The UV-visible spectrum of this film showed a red shift and increased bandwidth due to the small spacing between gold nanoparticles. The arrays were deposited on the top of pairs of gold electrodes to form 2D colloidal single electron devices. The electrode pairs were made by electron beam lithographic techniques, and the separation between tips of the two electrodes in a pair was about 100 nm. Electron transport measurements at low temperatures exhibited Coulomb blockade type current-voltage characteristics due to the charge effects. The assembled arrays have potential applications as nano electronics.