An electronic skin (e-skin) that can detect both normal and tangential forces with a differentiable signals output is essential for wearable electronics. A flexible, stretchable, and highly sensitive tactile sensor is presented that enables the detection of both normal and tangential forces, with specific opposite and thus easily being differentiated resistance changing outputs. The e-skin, which is based on two-sublayered carbon nanotubes (CNTs)/ graphene oxide (GO) hybrid 3D conductive networks, that are anchored on a thin porous polydimethylsiloxane (PDMS) layer, is synthesized via a porogen (GO wrapped NaCl) assisted self-assembling process. The fabricated CNTs/ GO@PDMS-based e-skin shows superior sensitivity (gauge factor of 2.26 under a pressure loading of 1 kPa) to tangential force, moderate sensitivity (−0.31 kPa −1 at 0.05-3.8 kPa, and −0.03 kPa −1 at 3.8-6.3 kPa, respectively) to normal force, and a high-reproducible response over 5000 loading cycles including stretching, bending, and shearing. For applications, the e-skin can not only detect wrist pulsing, discriminating different roughness of surfaces, but also produce an obvious responding to an extremely slight ticking (<20 mg) from a feather, and even can real-timely monitor human's breath and music in rhythm.

Wearable electronics are attracting increasing attention as recent developments in materials, mechanics, and manufacturing techniques create new opportunities for the integration of high-quality electronic systems into a single miniaturized Continuous monitoring of human physiological signals is critical to managing personal healthcare by early detection of health disorders. Wearable and implantable devices are attracting growing attention as they show great potential for real-time recording of physiological conditions and body motions. Conventional piezoelectric sensors have the advantage of potentially being self-powered, but have limitations due to their intrinsic lack of stretchability. Herein, a kirigami approach to realize a novel stretchable strain sensor is introduced through a network of cut patterns in a piezoelectric thin film, exploiting the anisotropic and local bending that the patterns induce. The resulting pattern simultaneously enhances the electrical performance of the film and its stretchability while retaining the mechanical integrity of the underlying materials. The power output is enhanced from the mechanoelectric piezoelectric sensing effect by introducing an intersegment, through-plane, electrode pattern. By additionally integrating wireless electronics, this sensing network could work in an entirely battery-free mode. The kirigami stretchable piezoelectric sensor is demonstrated in cardiac monitoring and wearable body tracking applications. The integrated soft, stretchable, and biocompatible sensor demonstrates excellent in vitro and ex vivo performances and provides insights for the potential use in myriad biomedical and wearable health monitoring applications.

We integrate multiple, independently addressable piezoelectric thin-film actuators into complex, 3D mesostructures.

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