Skin-triggered electrochemical touch sensation for self-powered human-machine interfacing

Touch sensation is an essential function for both living creature and artificial intelligent systems. Significant progress has been made for touch sensors in recent years, while the vast majority of the developed touch sensors suffer from complicated device configuration, high power consumption, or absence of capability to detect both static and dynamic stimuli. Here, we overcome these obstacles by proposing a new touch sensing modality, named skin-triggered electrochemical touch sensation (STETS). This STETS mechanism is based on two skintriggered electrochemical reactions happening at the interfaces between skin and two active electrodes. The STETS sensing modality features two key advantages compared to the existing touch sensing devices. Firstly, both static and dynamic touch stimuli could be resolved in a self-powered manner, compensating for the deficiency of conventional piezoelectric or triboelectric sensors in resolving static stimuli. Secondly, the STETS sensors compose of only two active electrodes and employ natural skin as the active electrolyte, which greatly simplifies the device configuration/fabrication, and meanwhile, gives rise to new characteristics that are challenging to achieve with conventional device configuraitons (including negligible deformation hysteresis, bending insensitivity, etc.). As promising applications of the STETS mechanism, electronic braille board, single-electrode and bending-insensitive electronic skin, as well as health monitoring devices are constructed and demonstrated. This presented STETS modality opens up new opportunities for the unconventional implementation of touch sensors in human -machine interfaces, smart wearables, and so on.