Potassium Sodium Niobate-Based Lead-Free High-Frequency Ultrasonic Transducers for Multifunctional Acoustic Tweezers

Abstract

Ultrasonic transducers may need to operate in direct contact with the human body, especially with the skin or closer to blood vessels. Eco-friendly lead-free materials and devices are therefore being vigorously developed for biosafety considerations. This work presents high-performance potassium sodium niobate [(K,Na)­NbO3, KNN]-based lead-free ceramics with composition-driven multiphase coexistence and their application on high-frequency ultrasonic transducers for multifunctional acoustic tweezers. A high piezoelectric constant d 33 value of 332 pC/N, a good Curie temperature T C value of 348 °C, and improved in situ temperature stability were obtained in the piezoceramics via the construction multiple phases near room temperature and domain engineering. One to three piezocomposites were further fabricated based on the synthesized ceramics for higher electromechanical coupling properties. Lead-free high-frequency transducers as multifunctional acoustic tweezers for precise and selective manipulation of microparticles were designed and manufactured with a high center frequency of 23.4 MHz and a broad −6 dB bandwidth of 75.4%. Additionally, a stable transducer performance was obtained over a test temperature range of 23–60 °C, indicating good thermal stability in environments with fluctuating temperatures. Research on lead-free high-frequency transducers for ultrasound imaging and precise and selective manipulation of microparticles demonstrates their broad potential in fields such as medical therapy and diagnosis.

Design and micromanufacturing technologies of focused piezoelectric ultrasound transducers for biomedical applications

“…Another application is to capture the cell and make it move following the moving trajectory of the transducer [202,203]. Jiang et al [127] fabricated a high-performance curved surface type 1-3 piezoelectric composite with a center frequency of 23.4 MHz. And as seen in figure 10(b), when the acoustic tweezers move at a lower speed, the trapped particles also follow the focus of the acoustic tweezers.…”

Innovative synthesis technique for high-performance dielectric resonator antennas: laser-induced shockwave sintering of potassium sodium niobate (KNN)

“…Furthermore, their application extends to nonvolatile memory devices, particularly in ferroelectric randomaccess memory (FeRAM) [12]. Additionally, their role encompasses acoustic devices, such as speakers and ultrasonic devices, as well as optical devices, owing to the intriguing optical properties exhibited by certain ferroelectric materials [13].…”

Composition Regulation of Potassium Sodium Niobate Thin Films through Post-Annealing under Alkali Element Atmospheres

“…Currently, notable progress has been achieved in employing KNN ceramic bulk across various applications such as transducers, sensors, etc. [8][9][10]. Meanwhile, some non-traditional applications based on KNN ceramics, such as piezoelectric composite fillers in flexible materials, have also been proposed [11,12].…”