Stretchable vertical graphene arrays for electronic skin with multifunctional sensing capabilities

Electronic skin (e-skin) has significant application prospects in soft robotics, prosthetics, medical monitoring, and wearable equipment. However, it remains a great challenge for e-skin to comprehensively mimic the multifunctional sensing capabilities and characteristics of human skin. Herein, vertical graphene arrays (VGA) were directly fabricated on the surface of a natural latex film using a facile method. The e-skin based on VGA combines the intrinsic properties of graphene and flexible substrates, as well as the morphological advantages of VGA, giving it multifunctional sensing capabilities similar to those of human skin. The e-skin not only exhibited multifunctional tactile perception of the pressure, airflow, and surface morphology of objects, but could also percept the difference in temperature between the detected object and the e-skin in a noncontact manner. Moreover, the sensing characteristics, including an ultrafast responsiveness (6.7 ms) and resilience (13.4 ms), a broad pressure sensing range (2.5 Pa – 1.1 MPa), a high sensitivity, and a robust cyclability, further demonstrate the similarity to that of human skin. The outstanding stretchability of the substrate endows the e-skin with an ultrabroad strain detection range (0.5%∼250%). Furthermore, the e-skin can still maintain the VGA structure, as well as the sensing capability under large tensile deformations. The facile preparation methods and excellent performance mean this e-skin is expected to be applied as a multifunctional integrated e-skin in smart flexible electronics.