Amorphous titanium dioxide film with improved electrochromism in near-infrared region

Titanium dioxide (TiO2) film and hybrid electrolyte are prepared via sol-gel method to fabricate solid-state electrochromic device (ECD). Electrochromic performance of the ECD has been studied in the near-infrared region. By optimizing the supplied pulse voltages and TiO2 film thickness, the high coloration efficiency (79.4 cm(2)/C at 1000 nm) has been obtained for the ECD under the pulse voltages of +/- 1.6 V. Additionally, the switch time of 16.1 s and 2.8 s is respectively achieved for coloring and bleaching at -1.6 and + 1.6 V. The fast switching speed between bleached and colored states results from the porous structure of solution-based TiO2 film that improves the Li+ ions release/insert. Stable current-cycle behavior has been achieved by cyclic tests with alternating pulse voltages within 2 x 10(4) s, which indicates excellent reversible stability in the ECD.