Impedance Measurements on Conductive Polymer Films. Literature Review

摘要

Conducting polymer films such as polypyrrole, polythiophene, and polyaniline211u001efilms are very attractive materials because of their unique redox, optical, and 211u001eelectrical properties. These characteristic properties have been applied to 211u001ebatteries, electrochromic devices, capacitors, and electrochemically controlled 211u001emembranes. To meet the requirements of these applications, many efforts have been 211u001edirected to the elucidation of charge transport mechanism. Charge transport in a 211u001efilm consist of electron transport and ion transport. Because ion transport in 211u001emost conducting polymer films is much slower than electron transport, ion 211u001etransport governs their redox properties. There are two possibilities in the mode 211u001eof ion transport. In the first one, reduction/oxidation of a film is accompanied 211u001eby the exclusion/insertion of anion to preserve charge neutrality inside the 211u001efilm. In the other, cation is inerted into or excluded from the film during its 211u001eredox reaction. Moreover, simultaneously with ion transport solvent molecules as 211u001ewell as ion pairs are be transported.