Synthesis of highly piezoelectric lead-free (K, Na)NbO3 one-dimensional perovskite nanostructures.

High-aspect-ratio single-crystalline KNN nanorods (length ~10-20 μm and diameter ~400 nm) are synthesized using a facile method based on a molten-salt reaction, whose formation mechanism has been revealed. The lead-free piezoelectric nanorods showing high piezoelectric coefficient d*33 up to ~230 pm V(-1) may be used in bio-sensing and energy-harvesting micro-devices.