Application of hybrid materials in solid-state electrochromic devices

Sol–gel derived cross-linked PEO/siloxane xerogels (designated as di-ureasils) were prepared using lithium trifluoromethanesulfonyl imide (LiTFSI) as a guest salt. In this paper we describe the assembly of a prototype solid-state electrochromic device (ECD) based on a four-layer sandwich structure, with the following configuration: glass/IZO/WO3/polymer electrolyte/IZO/glass. The electrochromic switching performance of these devices was characterized as a function of salt concentration. The average transmittance in the visible region of the spectrum was above 69% for all the bleached samples characterized. After coloration the structures assembled with d-U(900)nLiTFSI presented an average transmittance in the visible wavelength region above 22% and an optical density above 0.49.