Volume 8 Issue 2, February 2009

Despite recent advances, thermoelectric energy conversion will never be as efficient as steam engines. That means thermoelectrics will remain limited to applications served poorly or not at all by existing technology. Bad news for thermoelectricians, but the climate crisis requires that we face bad news head on.

The role of catalysts is greater than simply increasing the rate of a reaction. Modifying nanoparticles enhances two significant catalyst attributes: selectivity and thermal stability.

The chain-forming tendency of chalcogens like tellurium can be used as an efficient internal redox system capable of switching electronic conduction from n-type to p-type through small temperature changes.

Controlled assembly of diblock copolymers in which one of the blocks is crystalline enables the growth of a series of complex nano-architectures in a controlled fashion.

The spin injection efficiency from a ferromagnetic electrode into an organic layer has been successfully probed by two purpose-made techniques. The observed spin diffusion lengths of tens of nanometres hold promise for potential spintronics applications.

Nanocrystalline materials show significantly different mechanical properties than their bulk counterparts. An in situ microscopy study of Al nanocrystals is now able to directly observe the role of dislocations in tensile deformation and uncover a sensitivity to the strain rate.

Switching between n- and p-type conduction in a semiconductor can be done through doping. A fundamentally different behaviour has now been observed in Ag₁₀Te₄Br₃, as a transition from ionic to electronic conduction is achieved simply by heating, which could be used for switches or in novel electronic devices.

One of the challenges posed by spin manipulation in organic semiconductors is the difficulty of measuring the spin polarization and the spin diffusion length. This is now elegantly achieved by a low-energy muon spin rotation.

One of the challenges posed by spin manipulation in organic semiconductors is the difficulty of measuring the spin injection from a ferromagnetic contact and the subsequent spin diffusion length. This is now elegantly achieved by a two-photon photoemission experiment.

Present Li-ion batteries for portable electronics are based on inorganic electrodes made through non-ecological processes. Sustainable conjugated dicarboxylate organic salt anodes showing advantageous reversible capacities and thermal stability are now reported.

Colloidal synthesis can help to precisely control the shape and composition of catalytic metal nanoparticles, but it has so far proved difficult to use these particles in high-temperature reactions. Core–shell structures capable of isolating Pt-mesoporous silica nanoparticles have now been shown to be catalytically active for ethylene hydrogenation and CO oxidation at high temperature.

The selective formation of cis olefins would reduce the production of unhealthy trans fats during the partial hydrogenation of edible oils. Single-crystal surfaces with well-defined supported nanoparticle catalysts now show that platinum (111) surfaces can selectively promote the non-thermodynamic isomerization of trans olefins to their cis counterparts.

Tailoring the properties of polymer nanocomposites—polymers incorporating nanoparticles—is essential to develop biomedical, or even electronic, applications. It is now shown that accurate control of the nanoparticle concentration in nanocomposites prepared from athermal mixtures considerably varies the physical properties with respect to the host polymer.

A synthetic tool that uses living polymerizations driven by epitaxial crystallization is shown to create a range of complex micelle architectures made from diblock copolymers. Platelet micelles act as initiators for the formation of scarf-like structures with micellar tassels of controlled length, grown from specific locations.

Cancer vaccines developed so far typically rely on cell manipulation techniques in the laboratory followed by re-introduction of the cells into the patient. Now, a polymeric material is shown to program and control the trafficking of immune cells in situ, resulting in specific and protective anti-tumour properties.