Synergistic Enhancement of PEDOT on Nanocrystal-in-Glass Ti-Doped WO3 Thin Films for Applications in Electrochromic Smart Windows

WO3 with nanocrystal-in-glass (nanocrystal-embedded amorphous matrix) characteristics is recognized as a highly promising electrochromic material. The demand for flexible and large-area electrochromic technologies is pushing the advancement of low-temperature and large-scale processes for WO3 thin films. This study presents a functional ink designed for the low-temperature preparation of WO3 thin films using blade-coating technology, enabling scalable and cost-effective production. The optimized WO3:Ti-PEDOT hybrid electrochromic thin film demonstrates a high light modulation rate of 86.05% (@ 633 nm), a coloration efficiency of 54.1 cm2 C-1, an outstanding cycle stability exceeding 1000 cycles, and an ionic diffusion coefficient of 3.69 x 10-8 cm2 s-1. One reason for the remarkably improved electrochromic performance is the synergistic effect of the nanostructured WO3 glass-nanocrystal composites induced by Ti doping and the enhanced electrochemical reaction kinetics facilitated by the use of poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer, as a binder. This work demonstrates a feasible and cost-effective method for producing WO3-based films for electrochromic smart windows, serving as an alternative to the existing vacuum-based WO3 thin film production methods.