Professor Woong Kim’s Team Identifies Crystalline Structure of New Piezoelectric Material Joint Research Between KU and Dr. Yong-Il Kim of KRISS

The Korea Research Institute of Standards and Science (KRISS) announced that Dr. Yong-Il Kim of the New Functional Materials Metrology Center and Korea University’s Professor Woong Kim have identified the crystalline structure of potassium niobate nanowires, which consist of piezoelectric elements that produce electrical charge in response to mechanical stress. 

 Professor Woong Kim,
College of Engineering

The joint research team published its results in the January issue of the Journal of the American Chemical Society, a renowned journal in the field of chemistry.

A crystalline structure refers the unique arrangement of atoms or ions of a substance in three-dimensional space.

The team applied X-ray and neutron diffraction to identify the crystalline structure of potassium niobate nanowires. They are comprised of graphite, like diamond, but the degree of hardness is determined by the crystalline structure. Potassium niobate was found to have an orthorhombic structure at room temperature that transformed into a monoclinic structure in the presence of nanowires. In a monoclinic structure, two pairs of vectors are perpendicular, and the third intersects obliquely.

Potassium niobate nanowires can be used as piezoelectric materials that generate electricity with leftover mechanical energy from the applied stress on the ground during walking as well as from the shaking of buildings or bridges.

Lead zirconate titanate, or PZT, is widely used as a piezoelectric material, but an alternative to lead was needed. The replacement of PZT with potassium niobate will give birth to lead-free piezoelectric materials.