Advanced Materials

Nanogap electrodes are fundamental building blocks for nanometer-sized devices and circuits. They are also important tools for the examination of material properties at nanometer scale, even at molecular scale. The techniques for the fabrication of nanogap electrodes, the preparation of assembled devices based on nanogap electrodes, and the potential application of these nanodevices for the analysis of material properties are reviewed on p. 286 by Wenping Hu, Daoben Zhu, and Tao Li.

The synthesis of several categories of inorganic materials using, or in the presence of, ionic liquids is reviewed by Sheng Dai and co-workers on p. 261. The inside cover shows SEM images of hierarchically patterned macroporous TiO₂ prepared using a mixture of 1-octadecene (ODE) and an ODE-immiscible ionic liquid as the reaction medium.

Molecular effects on ransport across metal/organic molecule/semiconductor junctions, in contrast to metal/molecule/metal ones, can be solely electrostatic rather han be the result of the transmittance of molecules. In extremis, this yields metal/insulator/semiconductor (MIS) behavior in structures, apparently without insulator. This Progress Report also considers transport mechanisms, effects of new energy levels from molecule-electrode interactions, and temperature effects on ransport.

The intermediate band (IB) solar cell has been proposed to increase the current of solar cells while maintaining the voltage in order to produce an efficiency that ideally is above the limit established by Shockley and Queisser in 1961. The concept is described and the present realizations and acquired understanding are explained.

Stem cells respond to a range of cues found in their native tissue microenvironments and these same signals (e.g., mechanics, adhesion, topography) are now being incorporated into biomaterials to control stem cell fate. These approaches are particularly intriguing for the development of scaffolding to aid in tissue regeneration.

The current status of dendritic polyglycerols as functional dendritic architectures with particular focus on their biomedical applications is described in this Review. Drug, dye, and gene delivery for nanomedicine as well as non-fouling surfaces and matrix materials for regenerative medicine are highlighted as potential application areas.

Transition metal oxides exhibit a range of properties unparalleled by any other class of materials. Modern epitaxial film growth methods allow these properties to be controlled and utilized to gain fundamental understanding and create new functionality to underpin technological innovation. This Review provides a broad overview of recent research activity in oxide epitaxy, and includes highlights from material systems of high current interest.

Bio-microfluidics applies biomaterials and biologically inspired structural designs (biomimetics) to microfluidic devices. Microfluidics, the techniques for constraining fluids on the micrometer- and sub-micrometer scale, offers applications ranging from lab-on-a-chip to optofluidics. Despite this wealth of applications, the design of typical microfluidic devices imparts relatively simple, laminar behavior on fluids and is realized using materials and techniques from silicon planar fabrication.

The synthesis of inorganic materials using, or in the presence of, ionic liquids represents a burgeoning direction in materials chemistry. This technique provides an alternative to conventional inorganic materials synthesis, which relies heavily on water and organic molecules as solvents. In this Review, the use of ionic liquids in the preparation of several categories of inorganic and hybrid materials is summarized.

The fabrication of nanogap electrodes is key for the construction of nanodevices. Here some representative methods for the fabrication of nanogap electrodes, the application of nanogap electrodes in devices, and the analysis of material properties, are reviewed. The history, the research status, and the prospects and challenges in the research of nanogap electrodes are also discussed.