Novel Synthesis of Good Electrochromic Performance $WO_3$ Nanoplates Grown on Seeded FTO

Tungsten trioxide $(WO_3)$ has applications in various electrochromic devices and is fabricated using various techniques, which affect its electrochromic properties. In this study, tungsten trioxide $(WO_3)$ nanoplates were synthesised via a two-step facile synthesis process using a hydrothermal technique on seeded fluorine-doped tin oxide (FTO) glass substrates. $WO_3$nanoplates with high porosity were obtained using a fast and simple hydrothermal method. First, a seed layer was grown on FTO using a spin coating process. $WO_3$ nanoplates were then quickly synthesised on the seeded FTO glass using a hydrothermal technique at 200 ̊C for 1h. The nanoplates were characterizated by using XRD, SEM, Chronoamperometry and Cyclic Voltammetry techniques. The$WO_3$ nanoplates have got a crystal structure mixed monoclinic and hexagonal phases. The crystal grain sizes of the film was found to be 36 and 53 nm for the (011) and (200) sharpest crystal planes of monoclinic and hexagonal crystal phases respectively. The switching times of $WO_3$ nanoplates were determined as 1.28 s for colouration and 5.50 s of bleaching, and the diffusion coefficient was calculated as 4.2×10-10 cm2/s. As a result, the nanoplate structures with high porosity were successfully obtained and the $WO_3$ nanoplates showed good electrochromic performance with a good crystal structure, high diffusion coefficient, and short ion insertion time.