Photo-oxidation of σ-conjugated Si-Si network polymers

The ultraviolet-induced photooxidation of polyalkylsilyne network polymers has been examined. Infrared and x-ray photoelectron spectroscopies indicate a higher oxygen coordination about the Si atoms following photolysis than observed for the linear polysilanes. A photochemical pathway leading to cleavage of the alkyl groups from the Si backbone has been observed, the products of which then desorb as the respective alkanes or 1-alkenes via a thermally activated process. Finally, the photooxidation rate at 193 nm of thin polyalkylsilyne films is photon limited at fluences less than 1–5 mj/cm² per pulse; whereas above this fluenee, the photooxidation is oxygen limited. For the latter, the amount of oxygen chemically incorporated into the Si-Si network per laser pulse is dictated by the solubility level of oxidant in the film.