Efficient electrochromic device based on sol-gel prepared WO3 films

Tungsten oxide (WO3) films were prepared on indium-tin oxide (ITO) glass by sol-gel method. The influence of annealing temperature on the structural, morphological, optical, electrochemical, and electrochromic properties has been investigated. The film annealed at 250 A degrees C with an amorphous structure exhibits a noticeable electrochromic performance, such as the highest optical modulation of 58.5 % at 550 nm, high electrochemical stability, and excellent reversibility (Q (b)/Q (c) = 96.3 %). An electrochromic (EC) device based on WO3/NiO complementary structure shows improved performance. It exhibits high optical transmittance modulation of 62 % at 550 nm, excellent cycling stability, and relatively fast electrochromic response time (10 s for coloration and 19 s for bleaching).