A Strategy of Stabilization via Active Energy-Exchange for Bistable Electrochromic Displays

Abstract

As future energy-saving optoelectronics, bistable electrochromic (EC) materials/devices have high energy efficiency for potential applications as smart windows, displays, and information/energy storage, due to their ability to maintain optical states without consuming energy. However, further development is hindered by the lack of in-depth understanding of related key factors and universally applicable design strategies to achieve bistability. Herein, we report a new strategy based on active energy-exchange with the aid of proton-coupled electron transfer, which can dynamically adjust the highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels of materials to obtain good bistability from traditional nonbistable materials. This strategy was thoroughly studied and proven by taking quinone derivatives and bromocresol green derivatives as examples. The device obtained after further polymerization and optimization showed remarkable bistability, coloration efficiency, and application potential for energy-saving flexible displays. The success, challenges, and cognitive gains of this strategy not only accelerate the development of various energy-saving optoelectronic materials/devices, but are also likely to stimulate progress in physics, chemistry, and materials.