Silver Nanowire-Based Stretchable Transparent Electrodes for Precise Biosignal Sensing from Small Skin Areas

Area of Science:

• Materials Science
• Electrical Engineering
• Biomedical Engineering

Background:

• Stretchable transparent electrodes (STEs) are crucial for wearable biosensors, but traditional materials lack sufficient conductivity.
• Silver nanowires (AgNWs) offer good conductivity and transparency but have poor mechanical flexibility, limiting their application in stretchable electronics.

Purpose of the Study:

• To develop a high-performance STE with improved optoelectronic and mechanical properties for wearable biosignal sensors.
• To overcome the limitations of traditional AgNW networks in stretchable applications.

Main Methods:

• Fabrication of a grid-like AgNW network using a bar-coating method.
• Embedding the AgNW grid in a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) matrix.
• Transferring the composite onto a thermoplastic polyurethane substrate.

Main Results:

• Achieved a superior Haacke figure of merit (23.3 × 10^-3 Ω^-1) compared to isotropic AgNW networks.
• Demonstrated a low sheet resistance (~25 Ω sq^-1) and high transmittance (~85% at 550 nm).
• Exhibited minimal resistance change under 50% strain and durability over 500 cycles, enabling reliable biosignal acquisition (ECG, EMG, EEG) with high SNR.

Conclusions:

• The developed AgNW grid STE offers exceptional optoelectronic and mechanical performance.
• This scalable approach enhances the potential of AgNW-based STEs for next-generation wearable health monitoring.
• The STE enables reliable, high-SNR biosignal acquisition even from small skin areas.