Highly Sensitive, Flexible, Wearable Piezoelectric Sensor by the Integration of P(VDF-TrFE)/BaTiO₃ Composite Film and a-IZO TFTs

High sensitivity, highly integrated, low-power consumption, and highly flexible pressure sensors are essential for applications in fields such as electronic skin, smart robotics, and human-AI interaction. In this study, a highly sensitive integrated pressure sensor was prepared on a flexible PI substrate which includes a thin-film transistor (TFT)-based amplifier with a poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)]/BaTiO3(BTO) piezoelectric composite sensing unit. The sensing unit is connected to the extended gate of one In-doped ZnO (IZO) TFT, while the other IZO TFT serves as a load resistor for the amplifier. The integrated sensor can directly convert an external pressure applied to P(VDF-TrFE)/BTO composite into a voltage (or current) signal and amplify it without an additional charge amplifier. The results indicate the integrated sensor exhibits a low power consumption of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100~\sim ~200~\mu $ </tex-math></inline-formula>W, a high sensitivity of 0.64 V/kPa, and a rapid response time of 20 ms. The integrated sensor can be used to detect human movements and vital signs in real time, such as finger bending and stretching, pulse, and vocal cord vibrations, suggesting that the integrated sensor has a great deal of promise for application in wearable health monitoring systems.