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Due to their excellent electrical and mechanical properties, carbon nanotubes (CNTs) and graphene (G) have attracted increasing attention for the application of electronic skins (E-skins). In this paper, based on CNT/G hybrid films with a resistivity of 4.98 × 10–4 Ω·m, we prepared two kinds of E-skins with low power consumption and successfully realized the perception of multiple signals, including stretching, bending, temperature, and pressure. With a G mass fraction of 20%, the stretch/flexion/temperature-sensitive E-skin has an ultrahigh gauge factor (GF) of 1429 with a strain range of 0 to 10%, a GF of 0.92 rad–1 with a bending angle range of 0 to 90°, and a GF of 1.1 × 10–3 °C–1 with a temperature range of 25 to 85 °C; the pressure-sensitive E-skin has a GF of 7.45 kPa–1 with a pressure range of 15 to 10,015 Pa. In addition, we applied the prepared E-skins in human–machine interactions and wearable devices and confirmed their low power consumption below 74.20 nW in wearable applications. [ABSTRACT FROM AUTHOR]

Hand gesture recognition has attracted extensive research interest, as an essential approach for human−machine interaction. The development of flexible strain sensors offers the possibility of directly measuring the finger motion behaviors for accurate and cost‐effective hand gesture recognition, by placing the sensors on the fingers or integrating them on data gloves. Herein, the operation mechanisms of various flexible strain sensor designs are introduced first. Progresses on related materials and device structures to achieve the demanded figure of merits for flexible strain sensors are then reviewed. In addition to continuous performance optimization of the flexible strain sensor devices, the development of system‐level algorithms is shown to be important for not only recognition functions but also for suppression of nonidealities of the sensor devices, which are difficult to be addressed at device and material level. [ABSTRACT FROM AUTHOR]

Hand gesture recognition has attracted extensive research interest, as an essential approach for human−machine interaction. The development of flexible strain sensors offers the possibility of directly measuring the finger motion behaviors for accurate and cost‐effective hand gesture recognition, by placing the sensors on the fingers or integrating them on data gloves. Herein, the operation mechanisms of various flexible strain sensor designs are introduced first. Progresses on related materials and device structures to achieve the demanded figure of merits for flexible strain sensors are then reviewed. In addition to continuous performance optimization of the flexible strain sensor devices, the development of system‐level algorithms is shown to be important for not only recognition functions but also for suppression of nonidealities of the sensor devices, which are difficult to be addressed at device and material level.

Noncontact human-machine interactions (HMIs) provide a hygienic and intelligent approach to communicate between humans and machines. However, current noncontact HMIs are generally hampered by the interaction distance, and they lack the adaptability to environmental interference such as high humidity conditions. Here, we explore a self-powered electret-based noncontact sensor (ENS) with moisture-resisting ability and ultrawide sensing range exceeding 2.5 m. A megascopic air-bubble structure is designed to enhance charge-storage stability and charge-recovery ability of the ENS based on the heterocharge-synergy effect in electrets. Besides, multilayer electret films are introduced to strengthen the electric field by utilizing the electrostatic field superposition effect. Thanks to the above improved performances of the ENS, we demonstrate various noncontact HMI applications in harsh environments, including noncontact appliances, a moving trajectory and accidental fall tracking system, and a real-time machine learning-assisted gesture recognition system with accuracy as high as 99.21%. This research expands the way for noncontact sensor design and may further broaden applications in noncontact HMIs.