The synthesis and electrochemical study of new electrochromic materials vinylbipyridinium derivatives

In order to develop novel electrochromic materials, four vinylbipyridinium derivatives (VBPDs) were synthesized. The structures of VBPDs were characterized as the vinyl derivatives of viologen by NMR, IR spectroscopy and APCI-MS. The electrochromic behaviors and electro-optical properties of VBPDs were investigated by thermogravimetric analysis, cyclic voltammetry and UV–vis absorption spectra. Moreover, a serial of environmentally friendly electrochromic devices (ECD) based on VBPDs were assembled successfully and their electrochromic performances were further studied. It was found that VBPDs in ECDs showed superior cycling stabilities and well-defined reversibilities, and clear color changes from colorless to magenta/pink during the potential ranges from 0   V (in the oxidized state) to ±1.5   V (in the reduced state). To sum up, the VBPDs synthesized are promising candidates for visible electrochromic devices, for their outstanding electrochromic behaviors plus short and oversimplified synthetic routes.