Effect of Fluorination on Nano-Sizedπ-Electron Systems

The electronic structure of networked nano-graphites is investigated in relation to the effects of fluorine-introduced s p 3 -defects on the nano-sized π-electron system. In the low fluorine concentration region, the shrinkage of the π-conjugated system due to introduced s p 3 -defects reduces the orbital diamagnetism and modifies the electron hopping process between nano-graphite domains, and the edge-inherited non-bonding π-electrons having localized spins, which give a unique feature to nano-sized π-electron system, are seriously affected by the attack of fluorine atoms to edge carbon sites. In the intermediate fluorine concentration region, the spin density is enhanced by dangling bond spins generated by the local destruction of the π-conjugated system at interior carbon sites. The hyperfine-broadening of the linewidth and the reduced spin-lattice relaxation rate in ESR spectra suggest the isolated nature of the fluorine-induced localized spins in contrast to the edge-inherited spins.