3D printed Er3+ doped KNNLN piezoelectric ceramics for transparent ultrasonic transducer application

Abstract

The transparent [Li0.04(K0.5Na0.5)0.96]NbO3+0.5mol% Er2O3 (KNNLN-Er) lead-free piezoelectric ceramics were prepared by stereolithography technique. The influence of different sintering holding time (4h∼8h) on the micromorphology, relative density, shrinkage, electric properties, and photoluminescence properties were systematically investigated. The KNNLN-Er ceramics show the coexistence of orthorhombic and tetragonal structures. The grain size increases obviously and then decreases slightly with the holding time increasing. The KNNLN-Er ceramics exhibit good piezoelectric performance (piezoelectric constant d33∼97 pC/N, electromechanical couple coefficient kt∼0.36) and the moderate transparency of 34% when the holding time is 6h during sintering at 1120°C. Besides, the intensity of the photoluminescence emission spectra increases with the holding time increasing. Furthermore, in order to estimate the properties of the KNNLN-Er transparent ceramics, an ultrasonic transducer with a center frequency of 10.5 MHz was fabricated, which can be used for photoacoustic and fluorescence imaging. The results indicate that the KNNLN-Er ceramics have potential for multimode imaging applications.