Cyclometallated platinum(ii) complexes containing NHC ligands: synthesis, characterization, photophysics and their application as emitters in OLEDs

A series of novel luminescent NHC Pt(ii) complexes has been synthesized, characterized and used to prepare green OLEDs.

Switching intermolecular interactions by confinement in carbon nanotubes

Carbon nanotube encapsulation offers a mechanism to trap kinetically rather than thermodynamically favoured supramolecular arrays.

Polarisation charge switching through the motion of metal atoms trapped in fullerene cages

The formation of an endohedral fullerene can lead to charge transfer and the generation of a trapped positively charged metal ion. Using Ca@C60 and [Ca@C60](+) endohedral fullerenes as models, density functional theory calculations predict that the motion of a calcium ion within a fullerene is accompanied by large changes in electron density on the surrounding carbon cage. In the case of [Ca@C60](+), partial atomic charge distribution on the carbon cage is split between hemispheres into regions of positive and negative charge as Ca(n+) moves inside the fullerene cage (non-integer n strongly depends on position of the ion). It is proposed that within tethered fullerene cages the movement of partial atomic charge could form the bases of a molecular polarisation storage bit, and that adopted in the form of [Ca@C60](+) the presence of an overall charge may offer a route to either optical or electronic control.

Formation of nickel–carbon heterofullerenes under electron irradiation

Transformation of a graphene flake with an attached nickel cluster to new metal–carbon nanoobjects under electron irradiation is simulated.

Self-assembly of a sulphur-terminated graphene nanoribbon within a single-walled carbon nanotube

The ability to tune the properties of graphene nanoribbons (GNRs) through modification of the nanoribbon's width and edge structure widens the potential applications of graphene in electronic devices. Although assembly of GNRs has been recently possible, current methods suffer from limited control of their atomic structure, or require the careful organization of precursors on atomically flat surfaces under ultra-high vacuum conditions. Here we demonstrate that a GNR can self-assemble from a random mixture of molecular precursors within a single-walled carbon nanotube, which ensures propagation of the nanoribbon in one dimension and determines its width. The sulphur-terminated dangling bonds of the GNR make these otherwise unstable nanoribbons thermodynamically viable over other forms of carbon. Electron microscopy reveals elliptical distortion of the nanotube, as well as helical twist and screw-like motion of the nanoribbon. These effects suggest novel ways of controlling the properties of these nanomaterials, such as the electronic band gap and the concentration of charge carriers.

High frequency electromechanical memory cells based on telescoping carbon nanotubes

A new method to increase the operational frequency of electromechanical memory cells based on the telescoping motion of multi-walled carbon nanotubes through the selection of the form of the switching voltage pulse is proposed. The relative motion of the walls of carbon nanotubes can be controlled through the shape of the interwall interaction energy surface. This allows the use of the memory cells in nonvolatile or volatile regime, depending on the structure of carbon nanotube. Simulations based on ab initio and semi-empirical calculations of the interwall interaction energies are used to estimate the switching voltage and the operational frequency of volatile cells with the electrodes made of carbon nanotubes. The lifetime of nonvolatile memory cells is also predicted.