A topologically engineered honeycomb-like (2-0)-2 piezoceramic composite ultrasonic transducer with superior sensitivity

Piezoelectric ultrasonic transducers (PUTs) are widely utilized across a variety of technological fields; however, further advancement in ultrasonic transducer performance faces fundamental limitations. Herein, we report a brand-new (2-0)-2 piezoelectric ceramic composite (PCC) for enhancing sensitivity, featuring a topologically engineered honeycomb-like piezoceramic plate architecture [termed the (2-0) phase] uniformly embedded within the epoxy resin matrix (2-phase). This unprecedented novel structure effectively decreases the relative permittivity, acoustic impedance, and stiffness of the ceramic composite, while preserving the intrinsic main piezoelectricity and restraining the transverse piezoelectric effect. The resulting PCC shows a hydrostatic figure of merit (HFOM) dhgh of 3784.1 × 10−15 m2/N, representing a 312.3% improvement compared to that of the conventional 2-2 type PCC. Experimental results validate the performance enhancements of the (2-0)-2 PCC-based PUT, including a −6 dB transmitting bandwidth of 130 kHz, a higher transmitting voltage response and receiving voltage sensitivity, and an output voltage that is 46.4% higher than that of the conventional 2-2 composite transducer under identical excitation conditions. This proposed design strategy offers valuable guidance for the development and optimization of next-generation piezocomposite materials and high-sensitivity ultrasonic transducers.