Enhancing the electrochromic stability of Prussian blue based on TiO2 nanorod arrays

In this paper, we report a simple two-step hydrothermal method to improve the cyclic stability and transmittance of Prussian blue (PB) with TiO2 nanorod arrays (TNRAs). TNRAs were used as a nanostructured substrate to investigate the electrochromic properties of the PB/TNRA hybrid film. The PB/TNRA film shows excellent cyclic stability (83.8% after 1000 cycles) compared with the pure PB film (83.8% after 400 cycles). The improved cyclic stability was attributed to the increased adhesion between the PB film and the substrate and the alleviated volume expansion during the ion intercalation/deintercalation process. Moreover, the TNRA can reduce the reflectivity of the PB/TNRA film and increase the loading of PB. Therefore, the PB/TNRA film also shows a larger optical modulation (85.8% at 700 nm).