Ultra-high sensitivity and ultra-stable flexible wearable sensors based on hyperelastic semiconductor fibers

Advancing flexible pressure sensors with high sensitivity and a wide measurement range presents a major challenge and development focus in the field. Although current sensing mechanisms can achieve high sensitivity, their structural integrity and load-bearing capacity often suffer under significant pressure. Here, we report a new type of piezoresistive sensor utilizing a PVP/SnO2 nanofiber membrane as the sensing layer and carbon cloth as the electrode. The sensor is engineered to maintain extreme sensitivity and stability under conditions beyond those of traditional laboratory environments. Percolation theory is used to interpret the initial resistance decrease, and the quantum tunneling effect explains the rapid resistance drop at moderate pressures. At high pressure magnitudes, where the resistance variation is linear, the classical resistive formula is applied. Remarkably, it demonstrates a remarkable transition in resistance, similar to a semiconductor-to-conductor transformation under pressure, achieving a high sensitivity of up to 1.43 x 106 kPa-1 across a measurement range of 0-190 kPa. Additionally, the sensor exhibits a rapid response time of 80 ms and a relaxation time of 120 ms while retaining full textile flexibility, superior air permeability, excellent washability, enhanced reliability, and outstanding ultraviolet (UV) resistance. These exceptional characteristics highlight the potential of the sensor for wearable technology and pressure monitoring applications. Assembly and sensing mechanism diagram of double-layer PVP/SnO2 nanofiber sensor.