Photochromic and electrochromic dual-responsive devices: Integration of TiO2-Prussian blue composites and novel extended viologen

Photochromic and electrochromic devices have attracted remarkable attention due to their advantages of low power consumption, eye-friendliness, and broad application potential. However, developing dual-responsive devices with nice memory effect and rapid switching ability remains challenging. Here we report a novel strategy for fabricating dual-responsive photo-electrochromic device (PECD) based on TiO 2 -Prussian blue (PB) composite film and a novel extended viologen FHP . Exploiting the photocatalytic properties of TiO 2 , we successfully fabricated dual-responsive thin films and incorporated FHP as a complementary material to enhance the performance of the device. Notably, the resultant PECD exhibited remarkable performance, including long optical memory (33.91 h), fast response (4.6 s for coloring, 10.4 s for bleaching), high contrast (ΔT is 77.2 % at 692 nm), and excellent cycling stability (ΔT loss is smaller than 3.1 % after continuous working for 1000 cycles), highlighting their potential for advanced optical applications.