Raman Studies of Fluorine-Intercalated Carbon Fibers

Abstract

We report Raman scattering measurements on fluorine-intercalated graphite fibers (C_χF) for stoichiometries χ =7.8, 4.5 and 2.9. Lorentzian fits to our Raman lineshapes indicate the presence of two lines around 1600 cm⁻¹ and a broad line around 1355 cm⁻¹. The 1355 cm⁻¹ line is the disorder-induced graphite line and the ratio of the integrated intensity of this line to that of the 1600 cm⁻¹ doublet (R) provides a measure of the intercalationinduced disorder in the C_χF fibers. Both TEM and Raman studies indicate the presence of unintercalated graphitic regions in the C_χF fiber. The inverse relation between the average crystal planar domain size L_α, and the Raman intensity ratio R yields L_α ∼52Å for C_7.8F fibers and L_α ∼40Å for C_4.5,F and C_2.9F fibers.