A Flexible, Transparent, Ultralow Detection Limit Capacitive Pressure Sensor

Abstract The capacitive pressure sensor (CPS) with low detection limit and high sensitivity is crucial for the future development of electronic skins. Although introducing surface microstructures on dielectric layer may improve the sensitivity of CPS in some extent, it leads to a limited pressure‐response range due to the poor structural compressibility. Moreover, such microstructures deteriorate the transparency and flexibility of the final sensor and require costly microfabrication methods. Herein, a low‐cost high performance pressure sensor is developed by integrating the high permittivity and soft dielectric gel with the mechanically comparable ionic conductor. The device shows an unprecedented detection limit of 0.2 Pa, a high sensitivity of 4.2 kPa −1 in the low‐pressure regime of <1.2 kPa, and a fast response time of 13 ms. This ultralow detection limit allows for the efficient and accurate detection of weak pressure signals from acoustic waves to pulse and air‐flow, exhibiting promising application potentials in voice recognition, screening of cardiovascular diseases, and diagnosis of gas leakage. Furthermore, the combination of ionic conductor and dielectric gel also endows the capacitive pressure sensor with remarkable transparency, mechanical stability, and durability even under extreme environments. This study proposes a novel perspective for development of flexible and transparent electronic skins.