Comparison of solid state studies and electrochemical behavior of poly (dimethylsilane) and poly (dimethylstannum) film electrodes

Poly(dimethylsilane) (M. Wt. 2175) and poly(dimethylstannum) (M. Wt. 2650) have been successfully synthesized by electrochemical polymerization of dichloro-dimethylsilane and dichlorodimethylstannane, respectively, in a single-compartment cell equipped with aluminium electrodes in tetrabutylammonium tetrafluoroborate in dimethoxyethane as the supporting electrolyte. Thin films of the above polymers with a thickness of about 50-60 μm were prepared by physical vapor deposition technique. Si-Si and Sn-Sn catenations have been determined using Fourier Transform-Infrared spectroscopy, Nuclear Magnetic resonance spectroscopy and Ultraviolet-visible spectroscopic studies. Cyclic voltammetric measurements of the polymer thin film electrodes show the reduction peak of the polymers and give reversible response for the Fe3+ /Fe2+ redox couple. Impedance studies at different cathodic potentials clearly indicate that both the polymers behave like capacitive nature at less negative potentials and behave like a charge transfer carriers at more negative potentials. Mott-Schottky plot for these polymers reveal that the polymers are semi conducting nature of narrow band gap with high carrier densities and are p-type carriers.