Electrochromic Properties of Hexyl and Perfluorohexyl Substituted Symmetrical Viologens in Ion Gels
Vol. 57, No. 4, pp. 225-232,
Aug. 2020
10.12772/TSE.2020.57.225
PDF
Abstract
Herein, we present the electrochromic properties of viologen compounds with
hexyl and perfluorohexyl substituents in an ionic gel composition. Hexyl viologen (1), and
corresponding phenyl-inserted viologen (2) and perfluorohexyl phenyl viologen (3),
showed low reduction potentials of -1.4, -1.2, and -1.3 V, respectively. Spectroelectrochemistry
measurements of 1 revealed changes from yellow to blue, with a λmax of 596 nm. Further,
the phenyl-inserted viologens 2 and 3 showed green transitions, with a λmax of 600 nm,
due to longer conjugation by the phenyl moiety. In the cyclic stability measurements,
viologen 1 exhibited reversible color changes, with a transmittance change of 35.1% and a
corresponding change in optical density of 0.227. Its coloration efficiency was calculated to
be 83.6 cm2/C. Density functional theory calculations showed that both the terminal
substitution and phenyl insertion effectively controlled the band-gap energy of the
resulting viologen compounds. The findings of this study prove that substituted viologens
provide a simple and efficient method to produce wide color ranges using an
electrochromic approach. Hence, these compounds will find promising applications in
electrochromic displays and windows.
Statistics
Cumulative Counts from November, 2022
Multiple requests among the same browser session are counted as one view. If you mouse over a chart, the values of data points will be shown.
