Giovedì 2 ottobre 2025 - Ore 14:30 - Aula 21
Prof. Richard Robinson - Materials Science Department, Cornell University
  Seminario  

Magic-sized clusters (MSC) are identical CdS inorganic cores that maintain a closed-shell stability, inhibiting growth processes. Because MSCs are smaller than nanoparticles, they can mimic molecular-level processes, and because of their small size and high organic-ligand/core ratio, MSCs have “softer” inter-particle interactions, with access to a richer phase diagram beyond the classical close packed structures seen with larger particles. I will highlight some remarkable behavior we have recently found, including their ability to undergo a chemically-induced, reversible isomeric transformation between discrete states. These MSCs self-organize into films with hierarchical assembly that spans over seven orders of magnitude in length scale. Meniscus-guided evaporative assembly results in large-scale homochiral domains with anisotropy values (g-factors) near 1.1 and areas surpassing 6 mm2. These g-factors are among the highest reported for all semiconductor particles. Through Mueller matrix polarimetry spatial mapping we unravel the mechanism behind the formation of the self-organized chiral domains. Beyond optical properties, the multiscale self-organization behavior of these MSCs displays similarities to biosystems, providing a new platform for the design and study of materials.