Ultrahigh‐Frequency Flexible Triboelectric Ultrasound Transceiver Arrays for Inspection of Complex Surfaces

Acoustic devices based on triboelectricity have shown promising results in flexible ultrasonic sensing. However, the unidirectional mode of conversion of mechanical to electrical energy limits the bidirectional transmission of ultrasonic signals. In addition, it is challenging to fabricate ultrathin dense wearable ultrasound arrays. This study introduces a flexible high‐frequency triboelectric ultrasonic transducer array, with both transmission and reception capabilities for 3D imaging. The array features 8 × 8 individually addressable transducers in a thin‐film micro‐interlocking structure. Enhanced mechanical transfer and gap modulation improve the electrostatic force interaction and sensitivity to weak vibrations. The array demonstrates an impressive frequency response (0.2–10 MHz), high receiving sensitivity (22.2 dB), and transmitting vibration velocity (14.0 mm s −1 ). Its sensitivity is approximately six times higher than commercial polyvinylidene fluoride (PVDF) transducers of comparable size. The array can detect structural damage in various structures and enable 3D visualization of biological media. This study highlights a new path for triboelectric devices in flexible ultrasonic inspection.