Spider Web-Inspired Flexible Pressure Sensors with High Sensitivity and Adjustable Sensing Range

Piezoelectric pressure sensors often suffer from low sensitivity due to limited compressive stress or mismatched piezoelectric modes. Additionally, achieving controllable adjustment of their sensitivity and sensing range remains a significant challenge. Here, spider web-inspired flexible piezoelectric pressure sensors with a high sensitivity and adjustable sensing range are proposed. First, a radially polarized piezoelectric biomimetic film with 3D-architectured spiral microelectrodes is developed, achieving the d₃₃ mode under radial stress. Second, low-stiffness soft substrates are introduced to convert small axial compressive stress into significantly increased radial stress. The developed sensors with a cavity soft substrate exhibit high sensitivities of 3.356 V N⁻¹ (0.01–0.5 N) and 2.524 V N⁻¹ (0.5–10 N), which represent 55- and 41-fold improvements over conventional sensors, respectively, far surpassing previously reported strategies. Third, a simple method is proposed for altering sensor stiffness to tune sensitivity and sensing range. By increasing the bending stiffness, the pressure sensors achieve an extended sensing range (0.5–40 N) and an 11-fold enhancement in sensitivity. Furthermore, the proposed sensors not only demonstrate excellent cyclic stability (up to 50 000 cycles) and scalability but also enable highly sensitive detection of airflow velocity, breathing state, and distributed pressure.