Structural investigations of electrical conducting plasma polymerized films from 2-iodothiophene

Thin plasma polymerized films were produced in a microwave (2.45 GHz) plasma discharge using 2-iodothiophene as the initial monomer. The structure of these electrically conducting films (10−6–10−1 S/cm), the chemical state of the doping element iodine and the elemental homogeneity at the surface and in the films have been investigated by XPS, FTIR and AES. An interesting relationship was found that indicates some similarity to conventional polythiophene, prepared by electrodeposition. Besides covalently bound iodine, considerable amounts of I 3 − and I 5 − were detected and also a small number of O-I bonds were identified.