Skin-Inspired Flexoelectret Touch Sensor for Self-Powered and Self-Calibrated Tactile Imaging

While critical for human-machine interfaces, on-skin touch sensors struggle to replicate human skin's curved deformation mechanics and achieve simultaneous high sensitivity, linearity, robustness, and stability. Existing capacitive, piezoresistive, piezoelectric, or triboelectric mechanisms cannot effectively harness touch-induced curved indentation. We introduce a skin-inspired flexoelectret touch sensor that exploits flexoelectricity-converting strain gradients into electricity-to mimic skin's curved deformation geometry. This enables self-powered, self-calibrated tactile imaging through a novel mechanism establishing linear correlation between inhomogeneous deformation and electrical signal. The sensor achieves high sensitivity (the highest sensitivity up to ~835 mV/N), good linearity, exceptional robustness (>80,000 s continuous operation; >8,000 cycles), and immunity to temperature fluctuations, ultraviolet light illumination, and humidity interference. A 7 × 7-pixel array demonstrates shape-adaptive and touch-trajectory imaging capabilities. This technology unlocks transformative potential for wearable electronics and advanced human-machine interactions.