Absorption Spectra of the Polyacetylene Films Doped with BF3

Abstract

Optical absorption measurements are carried out on pure and BF₃ doped polyacetylene films over a wide wavelength region (200 cm⁻¹–54000 cm⁻¹). In the lightly doped polymer, the extra peak appears at 870 cm⁻¹ and it is assigned to the transition from the valence band to the impurity level. This band becomes more intense at low temperature. For the heavily doped films, the dc conductivity of the (CH)_x fibril is optically estimated to be σ₀=10⁴ Ω⁻¹ cm⁻¹. This value is in good agreement with the calculated value (σ₀=0.8×10⁴ Ω⁻¹ cm⁻¹) due to the tight binding model.