Volume 7 Issue 11, November 2008

After over a quarter of a century, the doors of the world's first synchrotron radiation source have closed. Its contribution to materials science in the past and the future should not be underestimated.

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.

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

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

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.

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.

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.

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

Increasing the carrier density of a material to the limit at which superconductivity can be induced has been a long-standing challenge. This is now realized in an insulator by using an electric-double-layer gate in an organic electrolyte.

The trapping of electrons by grain boundaries in semiconducting and insulating materials is important for a wide range of devices such as sensors, and solar and fuel cells. First-principles calculations on MgO, LiF and NaCl reveal a novel type of electron trapping at grain boundaries associated with the negative electron affinity of these materials.

A new polymer is investigated as a drug-delivery vehicle for the treatment of inflammatory diseases, such as cardiac dysfunction. The biocompatibility, neutral degradation products and controlled-release properties of the polyketal microparticles indicate the material’s promising future in inflammation inhibition.

A universal feature of disordered glasses is the appearance of the so-called boson peak in neutron-scattering experiments. A universal link between this boson peak and transverse phonons has now been discovered, and linked to locally favoured structures in the glass.

Defects can significantly alter the physical properties of materials. A detailed experimental analysis of defects in carbon nanotubes enables the relationship between the atomic response and the broadly available macrosopic behaviour to be captured.

To enable the development of devices based on the electrical manipulation of magnetic molecules, their magnetic state needs to be conserved when electrical contacts are applied. N@C₆₀ molecules have now been integrated as part of single-molecule transistors, and their spin states retained. This achievement may lead towards their use in high-density information storage and quantum-state control.

Characterizing medium-range order in disordered solids and liquids is crucial for elucidating their structure and transport properties, but it has so far proved difficult. Using a combination of X-ray diffraction and Raman scattering, the pressure-dependent and atomic-void structure of amorphous red phosphorous is determined.

Flexible electronics require that all parts can be printed on plastic substrates, but finding materials that can act as high-capacitance dielectrics is a priority. An emerging class of polymer electrolytes, ion gels, can do the job—with high capacitance and at low voltage.

In a device design that brings mechanical flexibility to silicon photovoltaics, Jongseung Yoon, Alfred J. Baca and colleagues demonstrate how transfer-printing of ultrathin silicon films onto flexible substrates leads to semitransparent and large-scale arrays of integrated solar microcells with high solar-energy conversion efficiencies of 6–8%.

Conversion electrodes for lithium-ion batteries are capable of high capacity but low energy efficiency and low voltages are problematic. The electrochemical reactivity of MgH₂ with Li shows promise in using metal-hydride electrodes for both lithium-ion-battery and hydrogen storage applications.