ELECTRONIC ABSORPTION AND RAMAN STUDIES OF BF4--DOPED POLYTHIOPHENE BASED ON THE SPECTRA OF THE RADICAL-CATION AND DICATION OF ALPHA-SEXITHIOPHENE

The electronic absorption and Raman spectra of as-polymerized BF4--dop ed polythiophene have been analyzed on the basis of the spectra of the radical cation and dication of alpha-sexithiophene, viewed as models of a positive polaron and a positive bipolaron, respectively. The Rama n spectra taken with laser lines between 632.8 and 1064 nm have been a ttributed to positive polarons existing in doped polythiophene, The Ra man results confirm that the two-band feature observed in the electron ic absorption spectra of doped polythiophene is attributable to polaro ns.