Lead-Free (K,Na)NbO₃-Based Materials: Preparation Techniques and Piezoelectricity

This mini review focuses on the effect of preparation technologies on the piezoelectric property of KNN-based materials. The piezoelectric properties of KNN-based ceramics can be optimized by controlling the condition for sintering and poling processes. The preparation method of textured and single crystals could realize an increased piezoelectric constant compared to that of corresponding ceramics. According to current developments in preparation technology, we also provide perspectives and outlooks of lead-free KNN-based materials.