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Novel penniform superstructures of BaWO4 nanowires have been successfully synthesized in catanionic reverse micelles by using a double-hydrophilic block copolymer as the directing agent. This synthetic method is very simple, mild, and controllable, and it provides a novel method for direct solution-growth of hierarchical nanostructures based on inorganic nanowires.

Highly charged hydrophilic superparamagnetic Fe3O4 colloidal nanocrystal clusters with an average diameter of 195 nm have been successfully synthesized using a modified one-step solvothermal method. Anionic polyelectrolyte poly(4-styrenesulfonic acid-co-maleic acid) sodium salt containing both sulfonate and carboxylate groups was used as the stabilizer. The clusters synthesized under different experimental conditions were characterized with transmission electron microscopy and dynamic light scattering; it was found that the size distribution and water dispersity were significantly affected by the concentration of the polyelectrolyte stabilizer and iron sources in the reaction mixtures. A possible mechanism involving novel gel-like large molecular networks that confined the nucleation and aggregation process was proposed and discussed. The colloidal nanocrystal clusters remained negatively charged in the experimental pH ranges from 2 to 11, and also showed high colloidal stability in phosphate buffered saline (PBS) and ethanol. These highly colloidal stable superparamagnetic Fe3O4 clusters could find potential applications in bioseparation, targeted drug delivery, and photonics.

A one‐step facile synthesis of submicrometer‐sized hollow silver spheres (see Figure) has been achieved in aqueous solutions by using double‐hydrophilic block copolymer (DHBC)‐surfactant complex micelles as removable templates. The unique silver shell structures are candidates for both fundamental research and applications.

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Considerable attention has recently been directed towards one-dimensional (1D) nanostructures, such as wires, rods, belts, and tubes, owing to their unique physical and chemical properties and potential applications in nanoscale devices. [1] In particular, much effort has been devoted to the controlled synthesis of inorganic nanotubes since the discovery of carbon nanotubes.[2] A variety of inorganic nanotubes based on layered or pseudo-layered materials have been synthesized by using high-temperature or hydrothermal processes; examples include boron nitride, metal dichalcogenides, metal dihalides, metal oxides and hydroxides, metal borates, as well as metals. [3] Alternatively, nanotubes made from silica, alumina, silicon, and metals that do not possess a layered crystal structure have been fabricated by employing various templates such as porous membranes, carbon nanotubes, inorganic nanowires/ nanorods, and organized assemblies of organic molecules, [4] however, these nanotubes are usually either amorphous or polycrystalline. Notably, there are a few reports of single-crystalline nanotubes composed of semiconductors with nonlayered structures. Single-crystalline GaN [5] and Si [6] nanotubes have been produced by epitaxial overgrowth against suitable nanowire templates using vapor deposition processes. Interestingly, single-crystalline tellurium nanotubes have been obtained via a solution-phase approach, i.e., the polyol process where ethylene glycol refluxed at 197 C served as both solvent and reducing reagent. [7] This soft solution processing strategy is promising but it still remains to be extended to inorganic materials other than tellurium. Therefore, it is a great challenge to develop new soft synthetic strategies that produce single-crystalline nanotubes from non-layered materials.As an important elemental semiconductor, selenium shows many interesting properties, such as a relatively low melting point (~490 K), a high photoconductivity (~8 10 4 S cm ±1 ), nonlinear optical responses, and a high reactivity toward a variety of chemicals, and it finds commercial applications in photovoltaic cells, rectifiers, mechanical sensors, photographic exposure meters, and xerography.[8] Since the availability of 1D selenium nanostructures is expected to bring in new types of applications or to enhance the performance of the currently existing devices as a result of quantum-size effects, a number of synthetic methods have been developed to fabricate selenium nanorods and nanowires. Monoclinic selenium (m-Se) nanowires with a polycrystalline structure were obtained by using the protein cytochrome c 3 to reduce selenate (SeO 4 2± ).[9]Xia et al. synthesized single-crystalline trigonal selenium (t-Se) nanowires via the reduction of selenious acid (H 2 SeO 3 ) with excess hydrazine by solution refluxing [10] or sonochemical approaches.[11] Subsequently, t-Se nanowires and nanorods were produced by the dismutation of Na 2 SeSO 3 under acidic condition [12] or the solution-mediated transformation from Se powders...

A photoelectrochemical solar cell based on porous ZnO-covered TiO 2 film has been fabricated with ruthenium bipyridyl complex as the sensitizer. The cell generated a shortcircuit photocurrent of 21.3 mA cm -2 and an open-circuit voltage of 712 mV under irradiation of 81.0 mW cm -2 white light from a xenon lamp with an overall conversion efficiency of 9.8%. Compared with the pure TiO 2 (anatase) film, the ZnO-covered TiO 2 film possesses more outstanding ability to transport electrons with an overall power conversion efficiency increase by 27.3%. Optical elctrochemical studies show that surface modification of TiO 2 with ZnO can increase the concentration of free electrons in the conduction band of TiO 2 . This result implies that the charge recombination is reduced in the process of electron transport through the porous network, which can decrease the photocurrent loss and hence improve both short-circuit photocurrent and open-circuit photovoltage.