Optical and Electrical Properties of Electrochromic Devices Depending on Electrolyte Concentrations and Cell Gaps

Abstract

The optical and electrical properties of electrochromic devices (ECDs) have been studied as a function of the electrolyte concentration and the cell gap. During tests, the electrolyte concentration was adjusted from 0.01 to 1 M LiClO 4 , and the cell gaps between the positive and negative electrodes were set at 25, 60, and 100 μm. By varying the electrolyte concentrations and the cell gap, various parameters such as the transmittance, response time, charge consumption, coloration efficiency, and bistability of ECD were comparatively analyzed. Viologen (VO) was used as the reduction electrochromic material, and triarylamine (TAA) was used as the oxidation material.

Tunable graduated filters based on electrochromic materials for spatial image control

“…(4) accurately describes the homogeneously switched transmission at each potential and again proves the concurrent coloration of TPB and viologen (for parameters see Supplementary Information). We observed an average coloration time and a bleaching time (switching time defined as 90% of the transmission change) which is an excellent result in comparison to literature 20–22,24,25 . When switching from 0 V to −1.6 V, we reach an average Michelson contrast of 82.1%, which corresponds to an optical density of 1.01.…”

On-chip high ion sensitivity electrochromic nanophotonic light modulator

“…22 While planar sensors based on WO 3 show about 30% modulation over roughly 60 mM Na + ion concentration difference ( λ = 5 M −1 ), 22 the present waveguide device possesses a Na + ion sensitivity of roughly ξ = 2 × 10 7 M −1 . A planar smart window based on polymeric EC materials was shown to exhibit 50% contrast difference in the off-state optical transmission when immersed in Li + ion containing electrolytes with concentrations between 10 mM and 1 M. 38 Such devices offer a great promise in ion concentration dependent optical transmission modulation.…”

Extending the Color Retention of an Electrochromic Device by Immobilizing Color Switching and Ion-Storage Complementary Layers

“…High color contrast between the neutral and oxidized states was also possible by using complementary triphenylamine and viologen layers. In this case, the electroactive compounds were covalently tethered to the anode and the cathode, respectively, by phosphonic acids [34,35]. This dual-layer device had the benefit of extended colorfast by eliminating the diffusion of the two electrochromes [34].…”