Articles in 2008

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.

Phase-change materials are widely used as non-volatile memories, for example in optical data storage, but the search for improved phase-change materials has proved difficult. Based on a fundamental understanding of their bonding characteristics, a systematic prediction of phase-change properties has now become possible.

A long-standing problem with molecular wires is their poor transport properties. Highly conductive and very long wires have now been synthesized by incorporating metal centres into rigid molecular backbones, which shows promise for their use in electronic devices.

Carbon-based structures are being intensively investigated for their use in electronic devices. A pronounced non-volatile switching is now observed in two-terminal devices made from graphitic sheets. The highly reliable switching mechanism is explained by the local breaking and rejoining of atomic bonds in the sheets.

Superconductivity is a complex and fascinating phenomenon, made more so by its coexistence with other collective electronic states. A study of the layered compound 1T-TaS₂ under pressure enables the various states of the material to be investigated and compared with other commonly studied layered superconductors.

Hydrogen generated from splitting water using a catalyst and solar energy is an ideal energy source. A polymeric carbon nitride photocatalyst that is thermally and chemically stable is now shown to produce hydrogen from water even in the absence of noble metal catalysts.

Nanomaterials are effective catalysts for many chemical reactions, however, their catalytic properties are most often determined by ensembles of nanoparticles, and so far only averaged results have been measured. Now, the heterogeneous reactivity and the surface structure dynamics of individual gold nanoparticles are revealed by monitoring single fluorogenic reactions.

Construction of tissue-engineering scaffolds that mimic cardiac anisotropy is a challenge. Now, accordion-like honeycomb scaffolds have been created that can form tissue grafts with preferentially aligned heart cells, and with mechanical properties that closely resemble the anisotropy of native myocardium.

Printing electronic circuits will usher in a new era in electronics. With ion gel dielectrics, unprecedented transistor performance and speeds at low voltage can be demonstrated.

Single doped defects in carbon nanotubes locally modify the energies of charge carriers and lattice vibrations. They can now be detected by inelastic light-scattering experiments.

Crystalline silicon solar cell arrays on flexible, transparent substrates may lead to unconventional new applications.

The high temperatures required for oxygen ion conductivity have hampered the development of practical applications of ionic conductors. Now superlattices made of yttria-stabilized zirconia and strontium titanate show promise for room-temperature devices.

There is more than enough power available from the Sun to satisfy the world's needs, so why are we not rushing to exploit it?

Amorphous solids show intriguing universal behaviour whose origins often remain poorly understood. One of these features, the boson peak, is now shown to be directly linked to transverse vibrations.

A polymeric delivery vehicle, with neutral degradation products, keeps inflammation at bay during sustained drug release following myocardial infarction.

Refractory ceramic liquids studied by containerless levitation and synchrotron X-ray scattering reveal an unusual density-driven liquid–liquid phase transition.

Despite the absence of consensus on a theory of the transition from supercooled liquids to glasses, the experimental observations suggest that a detail-independent theory should exist.