Iron Phthalocyanine Incorporated Metallo-Supramolecular Polymer for Superior Electrochromic Performance with High Coloration Efficiency and Switching Stability

In this study, we newly synthesized iron phthalocyanine incorporated iron metallo-supramolecular polymers (Pc-Fe-polymer) and investigated its electrochromic behavior in both solution and solid-state devices. The presence of a terpyridine-attached iron phthalocyanine (FePc-TP) spacer revealed long-wavelength absorption at 670–700 nm, and the metal-to-ligand charge transfer (MLCT) by Fe-terpyridine coordination induced another absorption at 578 nm. Consequently, the Pc-Fe-polymer covered broad ranges of visible and near-infrared regions. Furthermore, due to facile charge delocalization during the Fe2+ to Fe3+ redox process, the Pc-Fe-polymer exhibited enhanced electrochromic performances. The Pc-Fe-polymer film experienced reversible electrochromic switching by changing the color from dark blue to transparent green in both solution and solid-state devices using LiClO4 as an electrolyte. The Pc-Fe-polymer exhibited exceptionally high switching stability (>1000 times) and a high coloration efficiency of 346....