Ion gels composed of a copolymer and a room temperature ionic liquid are versatile solid-state electrolytes with excellent features including high ionic conductivity, nonvolatility, easily tunable mechanical properties, good flexibility and solution processability. Ion gels can be functionalized by incorporating redox-active species such as electrochemiluminescent (ECL) luminophores or electrochromic (EC) dyes. Here, we enhance the functionality of EC gels for realizing multicolored EC devices (ECDs), either by controlling the chemical equilibrium between a monomer and dimer of a colored EC species, or by modifying the molecular structures of the EC species. All devices in this work are conveniently fabricated by a "cut-and-stick" strategy, and require very low power for maintaining the colored state [i.e., 90 μW/cm2 (113 μA/cm2 at -0.8 V) for blue, 4 μW/cm2 (10 μA/cm2 at -0.4 V) for green, and 32 μW/cm2 (79 μA/cm2 at -0.4 V) for red ECD]. We also successfully demonstrate a patterned, multicolored, flexible ECD on plastic. Overall, these results suggest that gel-based ECDs have significant potential as low power displays in printed electronics powered by thin-film batteries.
Bibliographical noteFunding Information:
T.P.L. and C.D.F. acknowledge financial support from the Air Force Office of Scientific Research under FA9550-12-1-0067.
- electrochemical displays
- flexible electronics
- ion gels