MSE Seminar: Hao Yan, Stanford University

Description

Bridging molecular chemistry and nanoscience with diamondoids

Nature has evolved delicate chemical machineries such as enzymes, in which precise placement of atoms and molecular fragments in nanometer-scale scaffolds define their functionalities. Controlling synthetic nanostructure at the atomic level is crucial for modulating their properties and enabling a myriad of applications from energy harvesting to quantum computing. However, unlike the synthesis of small molecules that can be precisely mapped out, navigating the complex reaction landscape of nanomaterials with atomic resolution remains substantially challenging.

In this talk, I will discuss our efforts in tackling this fundamental question using atomically well-defined diamond clusters, known as diamondoids. Their sizes can be systematically tuned in the transitional regime between small molecules and nanoparticles, giving rise to unique properties and new mechanisms to control the forging and cleavage of chemical bonds. I will elucidate this with two examples. First, harnessing their low conformational entropies and strong van der Waals interactions, we use diamondoids to guide the synthesis of low-dimensional transition metal chalcogenides with atomically precise structures. Second, utilizing the mechanical rigidity of diamondoids, we realize pressure-driven redox reactions with no equivalents in conventional chemistry. These findings establish new paradigms to maneuver the structure-property relationship at nanoscale, and unveil strategies to extend their functionalities beyond the accessible realm of traditional synthesis.