Volume 9 Issue 6, June 2010

Alain Fuchs is the director of the Ecole Nationale Supérieure de Chimie de Paris and in January was appointed the new president of the French National Centre for Scientific Research, CNRS. Nature Materials asked him about his research and his new role.

Radionuclides encapsulated within carbohydrate-functionalized carbon nanotubes set new records for in vivo radiodosage, while demonstrating zero leakage of isotopes to high-affinity organs, such as the thyroid.

Nitrogen-vacancy centres in diamond are very promising candidates for quantum information processing in the solid state. However, a search to find defects with even more potential has now been launched.

Organic light-emitting field-effect transistors surpass the external quantum efficiency of analogous organic light-emitting diodes.

Bulk metallic glasses (BMGs) show good compressive mechanical properties that make them attractive for applications. However, BMGs tend to fail under tensile strain. Through secondary phases these problems can be remedied to some degree. A mechanism is now demonstrated where BMGs show enhanced tensile ductility though the deformation-induced precipitation of nanocrystals.

Solid-state materials showing giant caloric effects near room temperature could provide an alternative to cooling devices based on gas cycles. Strong emphasis has so far been dedicated to caloric effects induced by a magnetic field. It is now demonstrated that a small pressure applied to the compound Ni—Mn–In gives rise to a giant caloric response.

Quantum transport phenomena have been widely investigated in semiconducting compounds, but extending these studies to oxides is not simple owing to their low mobilities. It is now demonstrated that SrTiO₃ films can be grown by molecular beam epitaxy; the films show very high electron mobility, opening the way to oxide heterostructures with excellent transport properties.

A biomedical application of a nanoconjugate is now shown in vivo. Sealed carbon nanotubes filled with a radionuclide are functionalized with carbohydrate molecules without prompting cargo release. The stability and biocompatibility of the capsule together with the radioactive payload enables in vivo imaging of the system and delivery of a high-density radiodose.

Tailoring the thermal conductivity of nanostructured materials is a fundamental challenge for nano- and microelectronics heat management. It is now demonstrated how to modify the thermal conductivity of SiGe by engineering nanodot inclusions in regions as short as 15 nm. A similar approach could used on other materials, extending the range of thermal conductivities available.

An organic light-emitting transistor has now been fabricated with a trilayer heterostructure. This architecture is shown to prevent both photon loss at the electrodes and exciton-charge quenching, thereby dramatically improving device efficiency and establishing these types of transistor as a promising alternative to organic light-emitting diodes.

The formation of lithium dendrites on the metal electrode surface of lithium batteries can lead to short circuits, making them potentially unsafe and unusable. The use of in situ NMR spectroscopy provides time-resolved and quantitative information about the nature of metallic lithium deposited on lithium-metal electrodes.

Electronics that are capable of intimate integration with the surfaces of biological tissues create opportunities for improving animal/machine interfaces. A bio-interfaced system of ultrathin electronics supported by bioresorbable silk-fibroin substrates is now presented. Mounting such devices on tissue and then allowing the silk to dissolve initiates a conformal wrapping process that is driven by capillary forces.

The fact that cells sense and respond to the mechanical properties of their environment is now a well-explored concept, although the mechanism of this response is still unknown. Now it is shown that cells themselves can mechanically manipulate the materials surrounding them by pulling at connective points, providing a feedback loop to influence cell fate.