Femtosecond‐Laser‐Engineered Asymmetric Bilayer Microstructures for Ultrawide‐Range High‐Sensitivity Flexible Pressure Sensors

Abstract

Flexible pressure sensors are pivotal for wearable electronics and intelligent robotics, yet conventional single‐layer uniform microstructures suffer from a critical tradeoff between sensitivity and sensing range. Inspired by the dome‐shaped pressure receptors of varying sizes found in crocodile skin, this paper proposes and fabricates an asymmetric, bilayer microstructure array flexible piezoresistive pressure sensor based on one‐step femtosecond laser fabrication technology. The sensor uses polydimethylsiloxane (PDMS) as a flexible substrate, with micro‐dome arrays of different sizes fabricated on both surfaces using a femtosecond laser. This ensures high fidelity and consistency in the microstructure morphology. Benefiting from the asymmetric bilayer structural design, the sensor achieves high sensitivity (64.1 kPa − 1 ) and excellent linearity (R 2 = 0.985) across an extremely wide operating range of 0.5–2000 kPa, while also demonstrating fast response and recovery times (104 ms/38 ms), excellent cyclic stability (>10 000 cycles), and resistance to vibration interference. The microstructure remained stable even after 10 000 fatigue load cycles. It enables reliable geological identification for detector vehicles and precise object‐size classification for mechanical claws, demonstrating great promise for high‐performance robotic perception applications.