Our research is focused on the design and synthesis of atomically-defined inorganic building blocks that can be assembled into functional electronic and magnetic materials. We study the chemical and physical principles that govern the organization of molecular clusters into nanostructured materials and the emergence of collective physical properties that arise in these assemblies.
Conventional solid-state compounds are infinite, crystalline arrays of densely packed and strongly interacting atoms. The properties of the individual atoms dictate the interatomic interactions that are the basis for thermal, electrical and magnetic collective properties of advanced materials. While the Periodic Table is rich, it nonetheless contains only a limited number of elements. We synthesize nanoscale analogs of atoms (large molecular clusters) and assemble these artificial atoms into atomically-precise solids. Since we build our own ‘atoms’, we can fully tune their size, composition, electronic and magnetic properties. We control their assembly by adjusting the type, number and placement of the ligands that we append to the surface of the clusters. In effect we are encoding desirable physical properties in the building blocks and controlling their interactions in the solid-state. Once synthesized, we investigate the structural characteristics and the electronic, optical, thermal and magnetic properties of these solid-state compounds. We aim to design materials with multiple functionalities and emerging electronic and magnetic properties. We are particularly interested in compounds on the edge of stability, by definition solids that undergo a phase transition through the application of an external stimulus (for example, light, pressure, or magnetic or electric field).
We are also involved in a number of other projects. These include 1) developing synthetic approaches to assemble molecular clusters into precise and predictable nanostructures such as nanowires, monolayers and mesoporous materials; and 2) synthesizing luminescent and magnetic molecular cluster probes for the visualization of neurotransmitter release.
Students in our group are exposed to a broad range of topics and techniques, including chemical synthesis, structural and physical property characterization and device fabrication.
“Nanoscale Atoms in Solid-State Chemistry”, X. Roy, C.-H. Lee, A. C. Crowther, C. L. Schenck, T. Besara, R. A. Lalancette, T. Siegrist, P. W. Stephens, L. E. Brus, P. Kim, M. L. Steigerwald, C. Nuckolls, Science 2013, (DOI: 10.1126/science.1236259).
“Quantum Soldering of Individual Quantum Dots”,X. Roy, C. L. Schenck, S. Ahn, R. A. Lalancette, L. Venkataraman, C. Nuckolls, M. L. Steigerwald, Angew. Chem. Int. Ed. 2012, 51, 12473–12476.
“Electronic Transport and Mechanical Stability of Carboxyl Linked Single-Molecule Junctions”, S. Ahn, S. V. Aradhya, R. S. Klausen, B. Capozzi, X. Roy, M. L. Steigerwald, C. Nuckolls, L. Venkataraman, PCCP 2012, 14, 13841–13845.
“Prussian Blue Nanocontainers: Selectively Permeable Hollow Metal-Organic Capsules from Block Ionomer Emulsion-Induced Assembly”, X. Roy, J. K.-H. Hui, M. Rabnawaz, G. Liu, M. J. MacLachlan, J. Am. Chem. Soc. 2011, 133, 8420–8423.
“Soluble Prussian Blue Nanoworms from the Assembly of Metal–Organic Block Ionomers”,X. Roy, J. K.-H. Hui, M. Rabnawaz, G. Liu, M. J. MacLachlan, Angew. Chem. Int. Ed. 2011, 50, 1597–1602.
“Molecular Scaffolding of Prussian Blue Analogues Using a Phenanthroline-Extended Triptycene Ligand”, X. Roy, J. H. Chong, B. O. Patrick, M. J. MacLachlan, Cryst. Growth Des. 2011, 11, 4551–4558.
“Liquid Crystal Templating in Ammonia: A Novel and Facile Route to Micro- and Mesoporous Metal Nitride/Carbon Composites”, H. Qi, X. Roy, K. E. Shopsowitz, J. K.-H Hui, M. J. MacLachlan, Angew. Chem. Int. Ed. 2010, 122, 9934–9937.
“Coordination Chemistry: New Routes to Mesostructured Materials”, X. Roy, M. J. MacLachlan, Chem. Eur. J. 2009, 15, 6552–6559.
“Mesostructured Prussian Blue Analogues”, X. Roy, L. K. Thompson, N. Coombs, M. J. MacLachlan, Angew. Chem. Int. Ed. 2008, 47, 511–514.
“Ultraporous Nanosheath Materials by Layer-by-Layer Deposition onto Co-Continuous Polymer Blend Templates”, X. Roy, P. Sarazin, B. D. Favis, Adv. Mater. 2006, 18, 1015–1019.
“Controlled Preparation and Properties of Porous Poly(L-lactide) Obtained from a Co-Continuous Blend of Two Biodegradable Polymers”, P. Sarazin, X. Roy, B. D. Favis, Biomaterials 2004, 25, 5965-5978.