Preparation and simulation of high-frequency lead-free NBBT/epoxy 1–3 piezoelectric composites with high electromechanical coupling characteristics

In this article, we design and fabricate (1 − x)Na0.5Bi0.5TiO3-xBaTiO3 single-crystal/epoxy 1–3 piezoelectric composites (NBBT 1–3 composites) with high coefficients of electromechanical coupling and demonstrate their considerable potential for use in high-frequency ultrasonic devices. We conducted finite element simulations on samples of the NBBT 1–3 composite to optimize their dimensional parameters. We used the cut-and-fill method to prepare an array of the NBBT-based 1–3 composite with a spacing of 20 μm between elements. It exhibited an exceptionally high coefficient of electromechanical coupling kt of 80.8%, with measured resonant and antiresonant frequencies of 11.6 and 18.5 MHz, respectively. Lead-free NBBT 1–3 composites that can deliver excellent performance are highly promising for use in medical applications of high-frequency ultrasound, especially for the brain–computer interface and intravascular ultrasound imaging.