n-type WO₃ semiconductor as a cathode electrochromic material for ECD devices

A new electrochromic (EC) arrangement is deposited on fluorine doped tin oxide (FTO) coated glass substrate by physical vapor deposition method. In this method, in the beginning, the WO₃ nanoparticles powder are deposited with average rate of 0.4 Ås⁻¹ in vacuum on FTO substrate for 80 min, then the Ag nanoparticles powder is deposited on prior layer for 1 min, again, the WO₃ electrochromic layer is deposited on prior layers for 5 min. In the end, the layer of Ag nanoparticles is deposited for 1 min with the rate of 0.1 Å s⁻¹. The nanoparticles of WO₃ and Ag, as an n-type semiconductor acts as the cathode electrochromic material, while the nano-sized silver as a noble metal, plays the role of the electron trap centers to facilitate charge separation. That respectively have been used in fabricated electrochromic devices (ECDs), for this purpose, the temperatures of 100, 200 and 500 °C are selected and ECDs annelid for 2 min in vacuum. The thin film that annealed in 200 °C, exhibits good conductivity in cyclic voltammetry (CV) analysis and has a better EC performance. We obtain the maximum of current about 3.5 mA in oxidation state for this sample. Furthermore, the change of transmittance for this sample was upgraded to 40.30% at continuous switching steps. This arrangement (WO₃/Ag/WO₃/Ag) can be used in ECDs with its excellent properties.