Thermally stable electrochromic devices using Fe(II)-based metallo-supramolecular polymer

A solid-state electrochromic (EC) device with high thermal durability was successfully fabricated by the combination of Fe(II)-based metallo-supramolecular polymer (polyFe) as a cathodically coloring EC layer, a poly (methyl methacrylate)-based solid-state electrolyte layer, and Prussian blue (PB) as an anodically coloring EC layer between two indium tin oxide (ITO)-coated glass conducting substrates. Spray coating technique was used to make polyFe film on ITO-glass. Counter materials were investigated to improve the long-term durability and performance of solid state devices. The polyFe layer thickness was optimized at 240 +/- 50 nm, resulting in better electrochromic performance of the fabricated device with transmittance change of similar to 54% and 95% cyclic stability after 1000 cycles with a short response time by applying voltages of +2.7 V and -1.3 V reversibly. Importantly, the thermal stability of the fabricated solid device was also explored, and we achieved maximum temperature stability at 100 degrees C with 50% retention of device properties in this study.