F. Girard et al., SPECTROSCOPIC INVESTIGATION OF A POLYPYRROLE MOS42-/MOS3 COMPOSITE FILM ELECTRODE IN AQUEOUS KCL SOLUTION/, Journal of the Electrochemical Society, 142(7), 1995, pp. 2296-2301
Polypyrrole-tetrathiomolybdate-molybdenum trisulfide, PPy-MoS42--MoS3,
thin film coated tin oxide electrodes have been studied by W-visible
spectroscopy. The films are obtained by electrochemical polymerization
from an aqueous solution of 0.5M pyrrole and 0.5 mM (NH4)(2)MoS4 at a
potential of 0.7 V vs. SCE. The UV-visible spectroscopy data suggest
that both tetrathiomolybdate anions and molybdenum trisulfide are rele
ased from the film during the initial reduction sweep. potential cycli
ng also induces a modification of the polymer structure involving loss
of long-range order which is evidenced by a decrease of absorbance. A
nalysis of the absorbance data at 380 and 720 nm according to Nernst l
aw enabled the determination of the redox potentials which were found
to be equal to -0.26 and 0.07 V,respectively. The former is related to
polaron generation in the bandgap while the latter can be attributed
to bipolaron production in the bandgap.