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This study presents the comparative modifications in optical, structural and morphological properties of fullerene C 70 thin film induced by swift heavy ion irradiation and thermal annealing. Fullerene C 70 thin films are prepared by resistive heating method on quartz substrates. One set of the films are irradiated with 125 MeV Au ions at different fluences varying from 1×10 12 to 3×10 13 ions/cm 2 and second set of the films are annealed at temperatures varying from 50 to 350 ̊C for 30 minutes. The UV-visible spectroscopy and Raman spectroscopy are performed on pristine, irradiated and annealed films to investigate the modification in optical and structural properties after irradiation and annealing. UV-visible spectra show that the optical band gap of fullerene C 70 film decrease with increasing fluence and temperature. The experiment using Raman scattering exhibits the transformation of fullerene C 70 into amorphous carbon at higher fluences and higher temperatures as well. This transformation is evidenced by the presence of D and G bands of amorphous carbon in irradiated and annealed films. Atomic force microscopy is performed to observe the variation in surface roughness of films variation with irradiation and temperature. Swift ion irradiation induces the cylindrical zone so called “ion track” made of amorphous materials with in the fullerene C 70 thin films. The damage cross-section and radius of cylindrical zone is calculated to be 2.8 ×10 -13 cm 2 and 3.0 nm respectively using the kinetics of damage of fullerene C 70 . [ABSTRACT FROM AUTHOR]

We present deposition of uniform polyfullerene films on ITO substrates using a novel electrochemical concept based on the oxidation of C60 dianion (C602-) solution. The C602- 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]