An intrinsically stretchable and bendable electrochromic device.

Area of Science:

• Materials Science
• Electrochemistry
• Flexible Electronics

Background:

• Traditional electrochromic devices (ECDs) often use brittle indium tin oxide (ITO) glass electrodes, limiting their application in flexible and wearable technologies.
• Developing stretchable and transparent electrodes is crucial for next-generation electronic devices that can withstand mechanical deformation.

Purpose of the Study:

• To fabricate highly stretchable and transparent electrochromic devices (ECDs) using novel conductive polymer fiber electrodes.
• To evaluate the electrochromic performance and mechanical stability of these stretchable ECDs compared to conventional ITO-based devices.

Main Methods:

• Fabrication of stretchable electrodes using electrospun poly(3,4-ethylenedioxythiophene):polystyrene sulfonate) (PEDOT:PSS) fibers on polydimethylsiloxane substrates.
• Integration of a chitosan electrolytic gel and a TPA-BZT-TPA electrochrome onto the stretchable electrodes.
• Mechanical testing (stretching, bending) and electrochromic performance evaluation (contrast, coloration efficiency) under deformed conditions.

Main Results:

• Achieved stretchable and transparent electrodes with a sheet resistance of 1200 Ω sq^-1.
• The fabricated stretchable ECDs operated effectively when stretched up to 150% and bent to a curvature of 0.1.
• Demonstrated significant electrochromic contrast (ΔT ≈ 30% at 805 nm) and coloration efficiency (168 cm²C^-1), with 30% greater contrast than ITO-glass counterparts.

Conclusions:

• Stretchable electrochromic devices can be successfully fabricated using electrospun PEDOT:PSS fibers, offering superior mechanical flexibility and enhanced electrochromic performance.
• The developed materials and device architecture provide a promising pathway for durable and deformable electronic displays and smart windows.