No abstract

A microwave (MW) plasma reactor for the synthesis of polythiophene (PTh) thin films as well as in situ doping during polymerization process has been designed and assembled. Plasma polymerization parameters were studied. A good MW power was found to be in the range of 150-250W. PTh films were characterized by various spectrophotometric methods. IR analyses showed absorption frequencies of important functional groups. PTh films exhibited UV-Vis spectra indicative of increased conjugative systems as the MW power increased although at 300 and 380W partial fragmentation was evident. Surface analysis by SEM revealed a uniformly deposited film morphology. EDS results were also suggestive of partial fragmentation of the films at high MW powers. Preliminary conductive measurements revealed that the undoped films exhibit higher conductivity (3 to 9×10-5 s.cm-1) than PTh typically prepared from electrochemical methods.

This research is focused on improving electrical conductivity of conjugated polythiophene films fabricated by microwave plasma assisted polymerization process. Polythiophene thin films with 300 nm to 1.5 micron thickness were deposited on glass substrates in a highly uniform fashion as evident by Scanning Electron Microscopic analysis. An efficient incorporation of the iodine dopant into the films was also successfully performed to give thin films with 120-250 nm thickness. The films were characterized by various spectroscopic methods. Attenuated total reflectance-Fourier transform infrared spectroscopy showed absorption frequencies of important functional groups mostly characteristics of thiophene. The doped fabricated films exhibited UV-vis spectra indicative of increased -conjugation (439-535 nm). Results from energy-dispersive X-ray spectroscopy confirmed the presence of iodine in the films of upto 10%. Electrical conductive measurements revealed that the undoped films has the conductivity in the range of 1.4×10-5 to 1.0×10-4 S/cm.