Ultrafast Electrochromic Flexible Displays via Solvent-Induced Porous and Loosely Packed Films

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Organic electrochromic materials offer low power consumption for displays but suffer from slow response speeds.
• Limited response times hinder the development of dynamic electrochromic display technology.

Purpose of the Study:

• To develop ultrafast electrochromic materials by engineering side-chain polymers.
• To improve the response speed and optical contrast of electrochromic devices (ECDs).

Main Methods:

• Utilized tetrahydrofuran (THF) to induce solvation and hydrogen bonding in a hydroxyl-terminated side-chain polymer.
• Created porous electrochromic films with high surface area via solvent-induced phase separation during spin-coating.
• Fabricated multi-layered porous thin films for display prototypes on rigid and flexible substrates.

Main Results:

• Achieved coloration response time of 0.87 s and bleaching response time of 0.22 s with 70.89% optical contrast.
• Demonstrated ultrafast switching rates of 0.1 s (5 ms bleaching time) at a low operating voltage of 1.4 V.
• Successfully fabricated active and passive display matrix prototypes on both rigid and flexible substrates.

Conclusions:

• Side-chain engineering combined with solvent-induced assembly provides a general strategy for ultrafast electrochromic display materials.
• The developed porous films and fabrication method significantly enhance electrochromic performance, paving the way for dynamic display applications.
• Hydrogen bonding plays a crucial role in alleviating mechanical stress, enabling robust flexible electrochromic devices.