Synthesis and characterization of single-crystalline (K,Na)NbO₃ nanorods

A modified sol-gel method was used to synthesize single-crystalline lead-free (K,Na)NbO₃ (KNN) nanorods. The effects of calcination temperature and heating rate on the crystal structure and morphology were examined. At low heating rate, it was found that with increasing calcination temperature, the crystallization of KNN gradually completed and the size of the one-dimensional rods increased significantly. On the other hand, increasing heating rate changed the morphology of KNN from one-dimensional rods to cubes. The as-synthesized KNN nanorods calcined at 750 °C with heating rate of 1 °C/min were determined to be orthorhombic single crystals of 100-400 nm wide and 1-2 μm long.