Ion transport-triggered rapid flexible hydrovoltaic sensing

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• The hydrovoltaic effect shows potential for ion sensing via solid-liquid interface interactions.
• Current methods suffer from slow response times (minutes) due to ion diffusion equilibrium in nanochannels.

Purpose of the Study:

• To develop a rapid and flexible hydrovoltaic ion sensing strategy.
• To overcome the limitations of slow response times in existing hydrovoltaic sensors.

Main Methods:

• Utilized ordered nanochannels and gravity elimination to reduce drag resistance.
• Proposed a liquid-driven effect with low-resistance shear flow in semi-dry nanochannels for fast ion transport.

Main Results:

• Achieved an open-circuit voltage exceeding 4.0 V within 0.17 seconds, two orders of magnitude faster than previous methods.
• Demonstrated a wide ion sensing range (10⁻⁷ to 10⁰ M) and high sensitivity (-1.69 V dec⁻¹ for NaCl).
• Obtained distinctive multi-dimensional signals for selective ion sensing.

Conclusions:

• The developed flexible hydrovoltaic device offers a significantly faster and more efficient approach to ion sensing.
• This technology is suitable for selective ion detection and real-time sweat electrolyte monitoring.