To accurately detect human motion, a sensing material/device must be flexible, ultrasensitive to strain, and electrically and mechanically robust. However, existing electronics and sensors, which are either not flexible enough, or not ultrasensitive to strain, or suffering from poor on/off ratio and low charge mobility, do not meet these stringent requirements. Here, we demonstrate a flexible and ultrasensitive three-terminal strain sensor based on two-dimensional (2D) InSe for detecting human-motion activities. The 2D InSe exhibits a tunable bandgap and a large piezoresistive effect via strain engineering. Through electrostatic gating effect, the gauge factor of the sensor can be enhanced by 8-fold and 7-fold for a low tensile and compressive strain of only ±0.25%, respectively. Remarkably, the fabricated 2D InSe-based transistor achieves both a record high on/off ratio of ~10⁸ and an electron mobility of ~383 cm²/V s, superior to all existing ones. Furthermore, flexible InSe logic inverters with a high voltage gain of ~10 and a large noise margin of ~0.7 × V_DD (supply voltage) are realized under various strain conditions. This work paves the way to enable simultaneous integration of high-performance flexible sensors and electronics based on a common 2D InSe material platform towards achieving a fully integrated sensing system.

为了准确地检测人体运动，感测材料/设备必须具有柔韧性，对应变超敏感并且在电气和机械方面均坚固耐用。但是，现有的电子设备和传感器要么不够灵活，要么对应变不敏感，或者开/关比很差，电荷迁移率很低，却无法满足这些严格的要求。在这里，我们演示了一种基于二维（2D）InSe的柔性超灵敏三端应变传感器，用于检测人体运动。所述2D InSe系表现出的可调谐的带隙和大的压阻效应通过应变工程。通过静电门控效应，传感器的应变系数可以分别提高8倍和7倍，从而使拉伸和压缩应变分别仅为±0.25％。值得注意的是，所制造的基于2D InSe的晶体管实现了创纪录的约10 ^8的高开/关比和约383 cm ² / V s的电子迁移率，优于所有现有晶体管。此外，在各种应变条件下，都可以实现具有〜10的高电压增益和〜0.7× V _DD（电源电压）的大噪声容限的柔性InSe逻辑反相器 。这项工作为基于通用2D InSe材料平台的高性能柔性传感器和电子设备的同时集成实现了完全集成的传感系统铺平了道路。