A Self-Powered, Single-Mode Tactile Sensor Based on Sensory Adaptation Using Piezoelectric-Driven Ion Migration

A piezoelectric tactile sensor is beneficial for creating a self-powered system with a compact design, which is essential in electronic-skin technology. However, piezoelectricity is only capable of dynamic pressure detection because it responds to sudden environmental changes. Since it is common to add another sensing unit to detect static pressure that accompanies bulkiness, including a measuring apparatus, we demonstrate a self-powered, single-mode piezoelectric tactile sensor by fabricating a piezoelectric gel through the electrospinning technique. As piezoelectricity senses the dynamic pressure without an external power supply, ions detect the static pressure by maintaining the potential difference upon sustained pressure. Since each component outputs a voltage signal of the same type but different profiles upon pressure, it is possible to distinguish dynamic and static pressure in a single mode. Moreover, inspired by the sensory adaptation of mammalian skin, an ion-assisted piezoelectric tactile sensor efficiently detects concurrently stacked stimuli by decreasing the output signal for sustained stimuli. The sensitivity for superimposed pressure upon initial 14.7 kPa increases by more than four times compared to that without sensory adaptation for both dynamic and static pressure.