Flexible Electronic Skin with Multisensory Integration

Flexible electronic skins (E-skins) with human-like multiple sensing capabilities of perceiving various stimuli, have attracted more and more attentions for their wide applications in wearable electronics, health monitoring, humanoid robotics and smart prosthesis. However, to meet the rigorous requirements for these complicated applications, challenges still exist in multifunctional integration, high performance, simple structure, low-cost fabrication and easy signal processing. This review focuses on the significant sensing capabilities that are necessarily required in E-skins, including perceiving stimuli of pressure, temperature, humidity, flow and materials. Various mechanisms are utilized in multiple kinds of sensors in current study, such as piezoresistivity, thermoelectricity, electrical impedance, convective heat transfer, etc. Multisensory integration is the basic characteristics of E-skins that various stimuli are perceived simultaneously. There are mainly three mechanisms applied in multisensory integration, that is, direct-integration method, functional-materials based method and uniform sensing method. The advantages and disadvantages of each method are analyzed. Finally, the challenges and future development on multisensory integration of E-skins are summarized.