Logotype-selective electrochromic glass display

This paper describes a fabrication method of a logotype-selective electrochromic (EC) glass. The EC glass performance based on the sample size, WO3 film thickness, and internal impedances under various applied voltages are also discussed. The logotype-selective electrochromic glass was fabricated by the sputter deposition process. Both working and counter electrode were coated with ITO/WO3 films. The specific logotypes of “NCUT” and “NUU” can be displayed with positive and negative voltages applied to the EC glass. EC glasses of various sizes (1 cm2, 4 cm2, 9 cm2, 25 cm2, and 100 cm2) were also fabricated by sputter deposition process. When voltage (−3.5 V) was applied to the device, the active layer of the assembled device changed from almost transparent to a translucent blue color (colored). The average transmittance in the visible region of the spectrum for a 100 cm2 EC device was 73% in the bleached state. The best device, with a 140 nm WO3 active layer, had average transmittances in the colored and bleached states of 11.9% and 54.8%, respectively. Cyclic voltammogram tests showed that reproducibility of the colored/bleached cycles was good. Nyquist plots showed that increasing the device size decreased the current density, and the electrolyte impedance increased because of a low conductive electrolyte in the device.