Electrochromic Display Device Based on Amorphous WO₃ and Solid Proton Conductor

An amorphous WO 3 electrochromic display device (a-WO 3 ECD) employing a solid proton conductor was investigated. The resistivity of the solid proton conductor composed of p-toluenesulfonic acid (p-TsOH) and urea (1.2:1 in molar ratio) was 10 2 ∼10 3 Ω cm at a relative humidity of 60% (20°C). The a-WO 3 ECD using the mixture of p-TsOH/urea and glycerin (20 wt.%) exhibited satisfactory EC performances such as response time (0.4 s) and open-circuit memory (over 2 hours). The most attractive feature of the ECD was an excellent visual appearance in a white and diffuse background of the solid electrolyte layer.