High-performance zero-standby-power-consumption-under-bending pressure sensors for artificial reflex arc

The recent advancement of flexible pressure sensors leads to promising applications in electronic skins for human-machine interaction and bionic device for intelligent wearable field. The abilities of such sensors to possess zero power consumption in standby mode, high sensitivity and wide linear response range are critical yet highly desirable in real flexible-matrix-based scenes. Despite the myriad of the existing approaches, it is still challenging to fulfill these requirements simultaneously in a single pressure sensor. Herein, we demonstrate a high-performance, zero-standby-power-consumption flexible pressure sensor by introducing a tunable photoresist spacer (PS) sandwiched between the top truncated-pyramid microstructure polydimethylsiloxane (PDMS)/aluminum-doped zinc oxide (AZO) and the bottom polyimide (PI)/gold (Au) interdigital electrode (PDMS-AZO/PS/PI-Au). The fabricated pressure sensor is equipped with bending-insensitive and zero-power-consumption merit under the bending angle of less than 20.5° benefiting from the insulation effect of PS. As a result, the fabricated sensor exhibits ultrahigh sensitivity of 2200 kPa−1 in the ultrawide linear response range of 62 Pa-9.6 kPa and fast response and recovery time (<20 ms). Moreover, according to the finite element modeling (FEM), the introduction of the top and bottom microstructures is proven to offer multiple contacting stages (e.g. point contacting, point saturation and surface saturation) and further enlarged contacting area, resulting in ultrahigh sensitivity and wide linear response range, which are strongly supported by experimental results. As a proof of concept, an artificial somatic reflex arc is successfully integrated into a volunteer to tune the LED-lit brightness and quantities. We believe that our high-performance pressure sensor holds great potential for the applications in a broad range of actual flexible-matrix-based scenes.