08 NovMaterial Science and Engineering Graduate SeminarEngineering Dimensionality in Excitonic Low-Dimensional Silver MOCHAs (Metal-organic Chalcogenolate Assemblies)
Engineering Dimensionality in Excitonic Low-Dimensional Silver MOCHAs (Metal-organic Chalcogenolate Assemblies)
  • Dr. J. Nathan Hohman
  • Staff Scientist at The Molecular Foundry at Lawrence Berkeley National Laboratory
  • Thursday, November 08, 2018
  • 12:00 PM - 01:00 PM
  • Auditorium (Room 0215) between building 2 & 3
2018-11-08T12:002018-11-08T13:00Asia/RiyadhEngineering Dimensionality in Excitonic Low-Dimensional Silver MOCHAs (Metal-organic Chalcogenolate Assemblies)MSE Graduate Seminar - MSE 398 - Fall 2018Auditorium (Room 0215) between building 2 & 3Mazen E. Mero

​ABSTRACT: When reduced in size to the nanoscale, materials express compelling new phenomena. For example, abstracting single monolayers from lamellar van der Waals solids like graphene or the transition metal dichalcogenides (TMDCs) has been a straightforward route towards preparing freestanding materials with high confinement of electronic carriers. Strongly bound excitons and tunable properties in TMDCs have recently attracted considerable interest for ultra-lightweight photovoltaics, electrocatalysts, and spintronic materials. However, most 2D materials reported to date are either elemental or binary semiconductor phases, limiting the discovery to materials that can be exfoliated from bulk crystals or prepared in thin films on support substrates. Recently, crystalline hybrid materials like metal-halide perovskites and metal organic chalcogenide assemblies (MOCHAs) have been reported that combine the structural and electronic properties of inorganic monolayer materials with chemically configurable ligands. The inclusion of organic moieties incorporated in self-assembling, three-dimensional arrays present an opportunity to leverage chemistry to build new categories of materials having inorganic nanostructures isolated from one another, physically and electronically, by the supramolecular lattice composed of the organic ligands. Here, we consider the structure and organization of silver benzeneselenolate, a self-assembling layered hybrid structure, and examine its optoelectronic properties in the context of a 2D-like material. Synthetic manipulation of dimensionality and topology is used to prepare a family of related crystalline polymer systems, and the role of intermolecular forces and molecular geometry on the inorganic phases are considered in the context of transitions between 1D, 2D, and 3D coordination polymer systems. 

J Nathan Hohman 2.JPG



BIOGRAPHY: J. Nathan Hohman earned his PhD in chemistry from the Pennsylvania State University in 2011, working with Paul S. Weiss to study the surface science and molecular dynamics of ultrathin self-assembled monolayers. He moved to Stanford University and worked with Nicholas Melosh where he was part of a team that developed metal-organic chalcogenolate assemblies (MOCHA) as a platform for using self-assembly and crystal growth to build periodic ensembles of low-dimensional nanomaterials. He joined the Molecular Foundry in 2015, and leads a group specializing in the systematic control and design of dimensionality and connectivity of inorganic coordination polymers in pursuit of systematic intervention into the structure/function relationships intrinsic to materials. He aims to understand how optoelectronic properties emerge in material systems by systematic variation of structure.

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  • Mazen E. Mero

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