Professor Matthew R. Jones
Gene and Norman Hackerman Junior Chair
Norman Hackerman-Welch Young Investigator
Assistant Professor of Chemistry and Materials Science and NanoEngineering
Rice University
"Building Materials Using Molecules"
The properties of inorganic nanoscale particles are largely determined by their surfaces, as the fraction of surface atoms can approach unity asthe size approaches 1 nm. As a result, the coordination of ligands to the particle surface can quickly become the dominant energetic contribution to the system and therefore provides an opportunity to use molecular design principles to control the formation of well-defined inorganic materials. However, challenges in characterizing the ligand-particle interface and a lack of mechanistic understanding of the role of ligands in surface reactions has limited the implementation of these structures in a variety of applications. In this talk, I will discuss recent efforts by my group to address fundamental questions in nanoscale surface chemistry and leverage these insights to construct nanoparticle-based materials with novel properties. First, I will show that advanced cryogenic and liquid-phasetransmission electron microscopy techniques can be used to map the spatial distribution of ligands on a nanoparticle surface and directly observe the dynamics of symmetry breaking during particle growth. Second,I will report our finding that the “seed” nanoparticle that has been widely used as a precursor in anisotropic gold particle syntheses over the last two decades is, in fact, an atomically-precise inorganic cluster consisting of a 32 atom Au core with 8 halide ligands and 12 neutral ligands constituting a bound ion pair between a halide and the cationic surfactant: Au32X8[AQA+•X-]12 (X= Cl, Br; AQA = alkyl quaternary ammonium). This result establishes a molecular precursor with well-defined surface ligandsas the progenitor to larger nanostructures and is a critical first step in understanding particle growth mechanisms. Finally, I will show how control over the surface chemistry of tetrahedron-shaped particles facilitates their assembly into novel superlattices with chiral and quasicrystalline order. These materials, whose construction is enabled by the atomic scale understanding developed in my lab, will form the basis for future optical and/or mechanical metamaterials, highlighting the power of molecular control over inorganic matter.
Matt Jones
Matt Jones joined the Chemistry faculty at Rice in 2017 and is the Norman and Gene Hackerman Junior Chair. He received B.S. degrees in materials science and biomedical engineering from Carnegie Mellon University and completed his Ph.D. at Northwestern University as an NSF Fellow. Under the guidance of Chad Mirkin, his graduate work focused on the cooperative properties of DNA ligands functionalizing anisotropic nanoparticles and the ability for these systems to assemble into novel superlattices via base-pair hybridization. For his postdoctoral work, Matt was awarded an Arnold and Mabel Beckman Fellowship to study under Paul Alivisatos at UC Berkeley. There, he investigated single-particle non-equilibrium shape transformations of metal nanocrystals using liquid-phase transmission electron microscopy. His research interests at Rice rest at the intersection of systems science, nanoparticle self-assembly, and plasmonics/metamaterials.
117/119 Smith Hall