Optical and electrochromic properties of thin films of ambipolar polyimides with pendant groups based on thioxanthenone derivatives

The optical and electrochromic properties of thin films obtained by centrifugation from solutions containing ambipolar polyimides with pendant groups based on 9$H$-thioxanthene-9-one and its $S$-dioxide derivative are studied using spectral ellipsometry, spectrophotometry, and spectroelectrochemistry. It is shown that the spectral dependences of the refractive index $n(E)$ and the absorption coefficient $\alpha(E)$ as well as the electrochromic properties of polyimide thin films under electrochemical reduction and oxidation conditions strongly depend on the type of the pendant group. Based on the estimates of the band gap Eg a conclusion is made about the possible promising use of thin films of polyimides as working layers in memristors of a new type.