Low-voltage electrodeposition of fullerol thin films from aqueous solutions

A low-voltage (<2 V, three-electrode system) method for the cathodic electrodeposition of fullerol [polyhydroxylated fullerene, C60 (OH) n] from an aqueous solution has been developed for the synthesis of thin films. Scanning electron microscopy of the electrodeposited fullerol films shows that the films are microscopically uniform; the film thickness was observed to vary linearly with the deposition charge. X-ray photoelectron spectroscopy of the C 1s peak indicates that the carbon constituents of the electrodeposited films are electronically similar to the fullerol precursor. Infrared spectroscopy (IRS) confirmed that the fullerol moiety is intact upon electrodeposition and that the films are thermally stable up to 150°C. At higher temperatures IRS data suggest there is cleavage of a ketal or hemiketal group followed by hydroxyl group cleavage. The (direct) optical bandgap obtained from UV-visible spectroscopy of the electrodeposited film was 2.6 eV.