Conductive Poly(3-methylthiophene) Thin Films

The work described herein represents an efficient method in the deposition of poly(3-methylthiophene),P3MeTh,thin films utilizing a microwave plasma system in combination with a simultaneous doping with iodine.It was envisaged that,an alternative poly(3-methylthiophene),P(3MeTh),with an electron donating methyl substituent,would reduce the degree of ring opening which reportedly occur to a certain extent during the plasma polymerization process of its parent compound polythiophene.An alkyl substituent would also increase the solubility of the materials.P(3MeTh)thin film deposition has been performed utilizing microwave-induced plasma polymerization in order to directly grow films on glass substrates.Moreover,simultaneous doping of the so-formed polymer with iodine has been carried out as opposed to the post-synthesis doping method.This is aimed to prolong electrical conducting lifetime of the materials.The synthesized films were characterized by attenuated total reflection fourier transform infrared(ATR FT-IR)spectroscopy and energy dispersive X-ray spectroscopy(EDS)to confirm the incorporation of iodine dopant into the films.Scanning electron microscopy showed uniformly deposited films.It has been observed that the electrical conductivity of the doped film is 2 orders of magnitude higher than the undoped counterpart.The doped fabricated films exhibited UV-vis spectra indicative of increased π-conjugation(536 nm).Furthermore,electrical conductivity of the in situ doped P(3MeTh)is more highly sustained over a longer period of time.