Logotype-selective electrochromic glass display

Abstract

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 (1cm2, 4cm2, 9cm2, 25cm2, and 100cm2) were also fabricated by sputter deposition process. When voltage (−3.5V) 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 100cm2 EC device was 73% in the bleached state. The best device, with a 140nm 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.