Fabrication of crystals from single metal atoms

Abstract

Metal nanocrystals offer new concepts for the design of nanodevices with a range of potential applications. Currently the formation of metal nanocrystals cannot be controlled at the level of individual atoms. Here we describe a new general method for the fabrication of multi-heteroatom-doped graphitic matrices decorated with very small, ångström-sized, three-dimensional (3D)-metal crystals of defined size. We irradiate boron-rich precious-metal-encapsulated self-spreading polymer micelles with electrons and produce, in real time, a doped graphitic support on which individual osmium atoms hop and migrate to form 3D-nanocrystals, as small as 15 Å in diameter, within 1 h. Crystal growth can be observed, quantified and controlled in real time. We also synthesize the first examples of mixed ruthenium–osmium 3D-nanocrystals. This technology not only allows the production of ångström-sized homo- and hetero-crystals, but also provides new experimental insight into the dynamics of nanocrystals and pathways for their assembly from single atoms.

Effect of Temperature on the Nucleation and Growth of Precious Metal Nanocrystals

“…All crystals analysed matched with one or more of these four structures. At 20 °C, the osmium crystals do not seem to have a simple hexagonal structure (which is in accordance with our previous report). It should be noted that because of the very small sizes of the nanocrystals (made up of less than 200 atoms in most cases), one such analysis can lead to the observation of more than one structure for the same crystal depending on the frame of observation (one crystal can fit with one structure at time t , and with another structure a few milliseconds later).…”

Pseudo electron-deficient organometallics: limited reactivity towards electron-donating ligands

“…Our group has recently developed a strong interest in two 16-e ruthenium and osmium half-sandwich complexes based on a carborane ligand ([Ru/Os(η 6 -p-cymene)(1,2-dicarba-closo-dodecarborane-1,2-dithiolato)]), and investigated their applications in biology 16,34,35 and in the fabrication of nanomaterials. [36][37][38][39] The intriguing chemistry in solution of these electron-deficient complexes was also studied in order to understand their biological properties. [40][41][42] Owing to the steric hindrance of the bulky carborane ligand, which prevents the dimerization of the compounds and the formation of more electronic favored 18-e species, these metal-carboranes exhibit remarkable stability as 16-e monomeric species as first demonstrated by Jin and co-workers.…”

Isotope Substitution Extends the Lifetime of Organic Molecules in Transmission Electron Microscopy

“…AC‐HRTEM provides complete structural information about the whole molecule, not just its surface, with the spatial resolution reaching the sub‐Ångstrøm scale. Atomically thin carbon structures such as graphene, graphene oxide or single‐walled carbon nanotubes (SWNT) have been demonstrated as excellent substrates for molecules, providing mechanical support, efficient reduction of ionisation and suppression of molecular motion, thus enabling atomically resolved AC‐HRTEM analysis at the single‐molecule level.…”