Ultra‐Wideband Hybrid Triboelectric–Piezoelectric Acoustic Sensors Enabled by Acoustic Metasurface Lens for Environment Perception and Medical Imaging

Abstract Acoustic sensing plays a vital role in underwater detection, communication, and biomedical diagnostics. However, conventional acoustic sensors suffer from various limitations: capacitive and piezoelectric sensors exhibit narrow bandwidth and low sensitivity and rely on external power, while optical sensors, despite their high sensitivity, require complex instrumentation and high costs. Here, an ultra‐wideband acoustic sensor (UWAS) is presented that operates via hybrid triboelectric‐piezoelectric coupling and integrates a trapezoidal‐grooves acoustic metasurface lens (PTGs‐AML). The periodic trapezoidal grooves significantly enhance acoustic radiation, increasing it by up to 255% at 10 MHz compared to conventional rectangular grooves. This enhancement improves acoustic focusing and suppresses sidelobe effects. The UWAS delivers a broad frequency response (20 Hz–50 MHz), high sensitivity (11.3 V Pa −1 at 60 kHz), and a signal‐to‐noise ratio of 67 dB (at 150 kHz). Its response is frequency‐dependent: omnidirectional at 53 Hz, unidirectional at 50 kHz, and multidirectional at 13 MHz. The enhanced energy localization enabled by PTGs‐AML supports high‐fidelity audio recording, environmental noise monitoring, and biomedical imaging, including venous thrombosis detection and knee effusion diagnosis. This self‐powered and scalable sensor provides a low‐cost solution for diverse acoustic applications. Furthermore, the metasurface design offers a generalizable strategy to broaden the bandwidth of conventional capacitive and piezoelectric sensors, paving the way for next‐generation acoustic sensing technologies.