Flexible Reflectance-type Electrochromic Devices Based on Cr/Ag/WO3 Thin Films

Abstract

： Flexible reflective electrochromic devices have broad application prospects in e - paper displays ， camou⁃ flage ， and intelligent color - changing surfaces ， but there are still problems such as poor flexibility ， low optical con⁃ trast ， and poor stability. Indium - free reflective electrochromic electrodes with Cr/Ag/WO 3 （ CAW ） structure have been prepared by electron beam evaporation on glass and flexible PET substrates. CAW films have high reflectance and low surface resistance. The average visible light reflectance is up to 89. 2% ， and the surface resistance is only 1. 2 Ω/□. In terms of electrochromic properties ， CAW films show fast colored and bleached response times of 9. 3 s and 2. 0 s ， high optical contrast of up to 83. 0% （ 564 nm ）， wide range of reflective color modulation （ >40 nm ）， and excellent electrochemical cycling stability （ >4 500 cycles ） . In addition ， CAW films have good substrate compatibili⁃ ty. We prepared flexible CAW films and assembled patterned flexible electrochromic devices. The electrical proper⁃ ties of the flexible film remain almost unchanged after 2 000 consecutive bends and the optical contrast reaches 83. 2% at 574 nm. The devices realize rich reflected color dynamic regulation under different voltages. These results will provide simple and effective guidance for the construction of high - performance flexible reflective electrochromic devices ， and have certain application potential in the field of new display technology