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.