Toward Multifunctional and Wearable Smart Skins with Energy‐Harvesting, Touch‐Sensing, and Exteroception‐Visualizing Capabilities by an All‐Polymer Design

An all‐polymer design to realize multifunctional and wearable smart skin devices with energy‐harvesting, touch‐sensing, and exteroception‐visualizing capabilities is reported. The design process of the skin, material selection principles, and performance under different mechanical manipulations are systematically elaborated. Stretchable hydrogel electrodes are sandwiched by a triboelectric layer and a ZnS phosphor–embedded mechanoluminescent layer, while the mechanical stability is ensured by an in situ assembly configuration. Regarding the performance of the three capabilities, first, the smart skin can function as a triboelectric nanogenerator and delivers an output peak voltage of 180 V and a power density of 625 µW cm−2 with superb cyclic stability throughout 10 000 continuous contact–separation cycles. Second, the skin can detect a pressure limit of 0.58 kPa with a sensitivity of 0.23 kPa−1, where the location detection can be achieved by applying a pixel configuration to the device. Third, a light‐emitting response can be stimulated to allow for visualization of the magnitude and location of an applied force. Remarkably, the as‐developed smart skin exhibits robust vitality without degradation of functionality, even when the device is subjected to a high strain of 700%.