The fabrication of flexible organic electrochromic devices (ECDs) with long-term operational stability has remained a challenging task because organic electrochromes tend to degrade under the repeated application of their operating voltages. We report a new flexible organic electrochromic system in which positively charged electrochromes (methyl viologen, MV2+) are strongly combined with negatively charged conductive nanomaterials (graphene quantum dots, GQDs) through a strong electrostatic interaction that does not require an electrolyte, allowing for the fabrication of electrolyte-free flexible electrochromic devices. The non-covalent interactions (such as electrostatic, ?-? stacking, and cation-? electron interactions) of the MV2+-GQD nanocomposites were confirmed with zeta potential, photoluminescence, FTIR, and XPS measurements. This new carbon-based MV2+-GQD ECD in comparison with the conventional MV2+-KCl ECD showed very stable switching performance even under external bending stress, high durability under repeated application of operating voltage, and high thermal stability. Our electrolyte-free flexible ECD based on MV2+-GQD illustrates a promising direction in the development of flexible electrochromic displays.

Electrolyte-free electrochromic nanocomposite with graphene quantum dot-viologen for flexible smart windows

248th National Meeting (2014)

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