Volume 10 Issue 7, July 2011

Pavel Exner, the newly elected Vice President of the European Research Council and Scientific Director of the Doppler Institute for Mathematical Physics and Applied Mathematics in Prague, talked to Nature Materials about his role in the European funding institution, the value of peer review in identifying the best scientists, the rise of science metrics and the challenges of running an efficient evaluation system.

Results show that achievable improvements may make solar thermoelectric generators competitive with other solar power conversion methods.

A system comprising 'signalling' and 'receiving' modules — where the receiving module circulating in the bloodstream is directed to the tumour by a cascade triggered by the signalling module — improves the targeting effect of a nanomedicine.

Conventional magnetoresistive devices are composed of magnetic and non-magnetic films. It is now shown that, at low temperature, a carbon nanotube decorated with single-molecule magnets can function as an all-organic spin valve.

Stretching polymer electrolyte membranes increases water diffusion along the stretched direction. It is now shown that the enhancement in transport is a result of the alignment of domains of hydrophilic channels, and that transport anisotropy and alignment are linearly coupled.

Although X-ray tomography has proven to be an efficient tool for three-dimensional imaging, its application to light materials has not been too successful. A new X-ray spectroscopy tomography method has now been developed that allows the mapping of chemical bonding in various types of structures, as well as the imaging of soft materials in three dimensions.

Nanowires have many applications across a number of disciplines. So far, their length has been largely limited to mesoscale dimensions. Through the adaption of an iterative fibre-drawing process it is now possible to fabricate millions of ordered nanowires and nanotubes of almost infinite length.

In macroscopic spin valves, the current between two magnetic electrodes can be tuned by external magnetic fields. Here, a molecular-scale spin valve is demonstrated in which a single-molecule magnet, through its localized magnetic moment, modulates the conductance of a single-walled carbon nanotube quantum dot with magnetoresistance ratios reaching 300%.

Polymer electrolyte membranes selectively transport ions and polar molecules, and are of interest for applications such as polymeric batteries, fuel cells, mechanical actuators and water purification. Transport anisotropy is now shown to linearly depend on the degree of alignment, indicating that membrane stretching only causes domain reorientation without affecting channel dimensions or defect structure.

Container walls are known to have a significant influence on the dynamics of glass formation. Computations now suggest that structural order is the origin of the slower dynamics of a glass-forming liquid near container walls.

A very large Rashba-type spin splitting, which is a consequence of spin–orbit interaction, has been observed in the heavy-element semiconductor BiTeI. The results show the possibility, in principle, of using the material in spintronics devices in which the electron spin is controlled by electric currents.

Pure spin current—the flow of spin angular momentum involving no charge movement—could lead to highly efficient spintronic devices. It is now shown that through low-resistivity magnetic tunnelling junctions it is possible to induce spin accumulation in solid-state devices one hundred times higher than previously obtained. This is the main requirement for generation of large spin currents.

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. A highly efficient solar to electric energy conversion device based on nanostructured thermoelectric materials and high solar concentration is now demonstrated. The results show potential for cost effective solar thermoelectric generation.

Electrochemical energy can be produced by using solar energy to oxidize water, providing an abundant source of electrons, which are needed in fuel synthesis. The operation of an efficient and stable semiconductor nanocomposite anode, made of a protective TiO₂ layer that protects a silicon substrate during photoelectrochemical water oxidation in both dark and light conditions, is now reported.

A two-component nanoparticle system that communicates and enhances in vivo drug delivery and diagnostics has been devised. The system comprises ‘signalling’ nanoparticles that target tumours and then broadcast the tumour’s location to ’receiving’ nanoparticles in circulation, which carry therapeutic or diagnostic cargos, hence amplifying tumour targeting.