A new strategy to fabricate multicolor electrochromic device with UV-detecting performance based on TiO2 and PProDOT-Me2

Abstract In this work, we succeeded in providing a new strategy to incorporate two cathodic coloring materials into one electrochromic device (ECD) to obtain multicolor property. The device was fabricated using TiO 2 film and poly(3,4-(2,2-dimethylpropylenedioxy)thiophene) (PProDOT-Me 2 ) film as electrodes. PProDOT-Me 2 and TiO 2 are able to show independent coloration performances. Therefore, the device could switch among blue state (colored PProDOT-Me 2 ) and black state (colored TiO 2 ). Furthermore, the transmittance of device in black state achieved about 0% within 300–1500 nm wavelength range. With PProDOT-Me 2 used as the opposite electrode, operating voltage for TiO 2 film switching into fully colored state decreased from −3.1 V to −2.2 V. In addition, the device could act as an ultraviolet (UV) detector for which could change color in short-circuited state under UV light illumination. This work proposes an ingenious method to assemble multicolor ECD, and the declined operating voltage of TiO 2 films in device might contribute TiO 2 ECD industry applications.