Organic-inorganic hybrid electrochromic materials, polysilsesquioxanes containing triarylamine, changing color from colorless to blue

Abstract

Four kinds of soluble monomers, containing triarylamine (TAA) group with reactive siloxane group, were synthesized under mild conditions via the reaction between 3-(triethoxysilyl)propyl isocyanate (TEOSPIC) and four TAA derivatives, respectively. Then the corresponding colorless organic-inorganic hybrid materials (PSSOs) were derived from the hydrolytic condensation of the monomers. PSSOs revealed good solubility in polar solvents on account of the effect of propeller-like TAA unit as well as the auxo-action effect of the flexible chain within the monomers. The structural characteristics of these PSSOs were identified by ¹H NMR, ²⁹Si NMR, FT-IR spectroscopies and X-ray diffraction (XRD). The morphology, dynamic changes of the transmittance and current before and after electro-oxidizing reaction were studied, and didn't show significant change suggesting good stability of the PSSOs. Meanwhile, these PSSOs performed high contrast of optical transmittance change up to 84% with the highest coloration efficiency to 241 cm²·C^-1. Furthermore, electrofluorescent properties of PSSOs were investigated with high-contrast.