Colored electrolytes for electrochromic devices

Color tuning remains one of the main issues for electrochromic applications. Multicolored organic and inorganic electrochromic materials have been largely studied. Herein, a novel approach of color modulation is investigated: the electrolyte coloration. The color tuning is therefore not only due to electrochromic materials but addressed thanks to pigment addition in the electrolyte, which allows endless possibilities. A symmetrical PEDOT:PSS based display and a WO3//V2O5 display were elaborated in order to characterize this coloration process. The PEGDMA/PEGMA copolymer gel electrolyte was processed by thermal polymerization using AIBN and colored using four different pigments. Similar switching times and capacities were measured from one colored electrolyte to another. This easy to set up method multiplies the achievable colors without altering electrochromic device stability.