An Electrochemical Approach for Deposition of Polyfullerene Films on ITO Substrates.

We present deposition of uniform polyfullerene films on ITO substrates using a novel electrochemical concept based on the oxidation of C₆₀ dianion (C₆₀^2-) solution. The C₆₀^2- solution was prepared by the electroreduction of the C₆₀ solution in dichloromethane and its oxidation at ITO surface was carried out using linear sweep voltammetry (LSV) in the - l to 0 V range. The electrodeposited films were characterized by various techniques, such as, scanning electron microscopy, atomic force microscopy, Kelvin probe microscopy, high-resolution transmission electron microscopy, UV/Vis and Fourier transform infrared spectroscopy. The morphology of electrodeposited polyfullerene film was found to depend upon numbers of LSV scans used for its preparation. After 100 LSV scans, the films exhibited a globular morphology and were found to make a full coverage of ITO substrate. At higher scans, a second layer of polyfullerene was found to grow in the form of whiskers having length and diameter upto 200 and 0.4 μLm, respectively. The energy band gap for polyfullerene whiskers was found to be ∼0.7 eV. Experimental evidence show that C₆₀ polymerizes in the I-dimensional "pearl-structure" via [2+2] cycloaddition reaction. [ABSTRACT FROM AUTHOR]