Symposium FF03: Building Advanced Materials via Particle-Based Crystallization and Self-Assembly of Molecules with Aggregation-Induced Emission
Litao Sun, Southeast University
Exploring the Surface Effects of Sub-10-nm Materials from the Atomic Scale
Written by Alana F. Ogata
Differences in materials behavior observed for transitions from the macroscale to nanoscale is a well-known phenomenon in the materials world. These discrepancies are enhanced when studying nanomaterials that are sub-10 nm in size where crystalline nanoparticles can exhibit liquid-like properties. Crystalline materials that behave as liquids sounds like a juxtaposition, but is one that Litao Sun brings to life with in situ TEM imaging of sub-10 nm metal particles. Surface atoms occupy ~62% of the atomic positions available in a sub-10 nm nanoparticle compared to larger nanoparticles where this percentage can drop to 0.036%. Surface atoms are flexible and can be reconstructed into different geometries giving rise to the liquid-like behavior of sub-10 nm nanoparticles. Sun showed a video of a nanoparticle with clear lattice fringes, indicating crystallinity, being pressed to a flat disc and completely recovering shape upon removal of the probe. The sub-10 nm particle can be squished multiple times and bounce back to its original state while maintaining crystalline structure. Sub-10 nm nanoparticles covered with a single layer of graphene will deform under the same external force and retain this deformation due to the rigid nature of graphene.