Flexible triboelectric nanogenerator toward ultrahigh-frequency vibration sensing

Flexible high-frequency vibration sensors are highly desirable in various real-world applications such as structural health monitoring, environmental monitoring, and the internet of things. However, developing a facile and effective method to fabricate vibration sensors simultaneously featuring high vibration frequency response-ability and flexibility remains a grand challenge. Herein, we report a flexible ultrahigh-frequency triboelectric vibration sensor (UTVS) prepared by a layer-particle-layer structure. Owing to the flexibility of the materials (i.e., polyethylene terephthalate membrane) and the ultrahigh-frequency vibration response-ability of internal microparticles, the flexible UTVS exhibits an enhanced working frequency range of 3–170 kHz, which is much broader than previously reported triboelectric vibration sensors. Moreover, the UTVS can work not only in a flat state but also in a bent state due to its flexibility and the unique layer-particle-layer structural design. The UTVS shows nanometer-level vibration response-ability, omnidirectional response, stability in the temperature range of 10–70 °C, good frequency resolution of 0.01 kHz, and excellent performance in burst vibration detection (e.g., pencil lead break events and impact events from falling steel balls). With a collection of compelling features, the device is successfully demonstrated in vibration monitoring of curved structures (e.g., real-time water pipeline leak monitoring). Such a flexible ultrahigh-frequency triboelectric vibration sensor holds great potential in a wide range of practical applications, such as communication, health care, and infrastructure monitoring.