UV-VIS NIR AND TRANSPORT STUDIES OF CHEMICALLY SYNTHESIZED SOLUBLE POLYPYRROLE/

Doped polypyrrole which is soluble in various organic solvents (m-cres ol, chloroform, DMSO, NMP etc.) is synthesized. Homogeneous solutions prepared from the solvents show different behaviors at near IR region depending on the solvent used. The results may be explained by PPy con formation change depending on polarity and aromatic interaction of sol vents and dopants. Amorphous X-ray diffraction pattern is observed in flexible free standing films cast from these solutions. The electrical conductivity of the materials is 10(-2) similar to 10(8)S/cm at room temperature. Temperature dependence of dc conductivity (sigma(dc)) ind icates that these materials show the three dimensional variable range hopping (VRH) model and show the relatively strong localization of cha rge. From the EPR experiment of PPy-NSA (m-cresol) sample, the density of state of the system is estimated as similar to 0.06 states/eV ring .