Seungbum Hong
Korea Advanced Institute of Science & Technology
Plenary Talk - 6
Visualization of Polarization and Ion Distribution in Functional Materials
Seungbum Hong
Department of Materials Science and Engineering, KAIST, Daejeon, 34141, Korea
Ion is the building block of most of the ceramic materials. In ceramic materials, positive ions and negative ions are neighboring each other with mostly ionic bonding at atomic scale. Sometimes, polymer and semiconductor materials contain ions that can diffuse in and out of them. In the meantime, polarization charges of ferroelectric materials are screened by equal amount of surface charges with opposite polarity in ambient conditions. As such, imaging the location, charge as well as the velocity of each ion and polarization will greatly enhance our understanding of electrochemical properties of ferroelectric materials. Here I present our research on various imaging methods of polarization using proxies like piezoelectric strain, screening charges, and friction coefficient, which can be used to image ferroelectric polarization. Furthermore, I will show how these contrast mechanisms can be applied to energy harvesting and chemical mechanical polishing. In addition, I present our research on various imaging methods of ions and charged defects using proxies like electrochemical strain, and electric charges, which can be used to image ion distribution. Finally, I will show how imaging ion and electron conduction path can help understand the nanoscale behavior of battery materials.