An electrochromic device based on dynamic coordination and the dissociation of Fe2+/Fe3+ and a leuco dye with an improved cycle life

Abstract

Based on the dynamic coordination and dissociation of a leuco dye and Fe²⁺/Fe³⁺, we constructed an electrochromic system where the coloring unit and redox unit were separate. This electrochromic system combined the advantages of the stability of the metal ions and the color adjustability of the dyes. The electrochromic mechanism was found to be universal to multiple leuco dyes and the device showed an absorption change of 0.25 and a coloration efficiency of 192 cm² C⁻¹. Moreover, compared with our previous work, the cycle life was effectively improved (up to 4900 cycles), which was suspected to result from the smaller oxidizing potential of Fe²⁺. This approach to improve the cycle life of electrochromic devices may inspire further important results in the future.