Natural Al₂O₃ Nanodielectric-Based Flexible Sensor with Triple Insensitivity for Healthcare and Robotics

Flexible pressure sensors are critical for advanced systems such as electronic skins and human-machine interaction. Among them, ionic capacitive pressure sensors have attracted widespread attention due to their exceptional flexibility and sensitivity. However, variations in ambient temperature, humidity, and operating circuit frequency significantly degrade the measurement accuracy of ionic capacitive pressure sensors and increase the complexity of subsequent signal processing. This paper proposes a capacitor structure based on the Al-Al₂O₃-CB interface, which achieves temperature insensitivity (-5 °C-45 °C), humidity insensitivity (20% RH-80% RH), and frequency insensitivity (volatility <3% within the range of 100 kHz-1 MHz), while maintaining high sensitivity (24.62 kPa^-1) and fast response and recovery time (33 ms/16 ms), and this design can substantially reduce circuit calibration complexity for sensor systems. The sensor's performance has been validated in various application scenarios, including physiological signal monitoring, gesture recognition, and robotic tactile sensing. By further integrating communication electronic modules, the sensor system offers wheelchair control based on hand movement perception, providing enhanced accessibility and convenience for patients with muscular weakness and other special needs.