Enhanced Percolation Effect in Sub-100 Nm Nanograting Structure for High-Performance Bending Insensitive Flexible Pressure Sensor

초록

Flexible pressure sensors have emerged as indispensable components in advancing wearable electronics, healthcare systems, and next-generation human-machine interfaces. To enable these applications, significant progress has been made in improving the sensitivity of flexible pressure sensors. However, achieving bending insensitivity-crucial for reliable pressure detection under dynamic and curved conditions-remains a critical challenge. In this study, a high-performance flexible capacitive pressure sensor is presented that successfully integrates bending insensitivity with enhanced pressure sensitivity. By leveraging the percolation effect within a sub-100 nm nanograting structure, the design of the pressure sensor is optimized through numerical analysis and finite element method (FEM) simulations. Fabricated using a nanoscale wet-chemical digital etching process and nanoimprint lithography, the sensor features a sub-100 nm valley nanograting structure. It exhibits an exceptional sensitivity of 0.05 kPa(-)(1), achieving capacitance changes 4.2 times greater than those of flat substrate designs. Furthermore, the sub-100 nm nanostructured pressure sensor effectively reduces bending strain to 0.175 times that of flat substrates, ensuring stable performance even at a 2.5 mm radius of curvature. This highly reliable flexible pressure sensor array enables real-time pressure mapping and human artery pulse monitoring, making it highly suitable for tactile and wearable sensing applications.

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