Advanced Materials

Quasi-periodic colloidal networks can be constructed on the basis of polymorphic meniscus convergence (MC) in an air-cavity-embedded, nanocolloidal system, report Sin-Doo Lee and coworkers on p. 4172. Depending on the flow associated with the air-cavities, the colloidal particles are self-organized into nanowires through binary MC, hexagonal networks with Y-junctions through ternary MC and square networks with X-junctions through quaternary MC, reflecting the flow symmetry according to the air-cavity deformation.

Bin Liu and co-workers report on p. 4186 on a water-soluble organic/inorganic hybrid nanodot based on polyhedral oligomeric silsesquioxane (POSS) and conjugated oligoelectrolytes for twophoton fluorescence imaging of cellular nuclei. The small size of the dots (∼3.3 nm) impart nucleus permeability and substantial DNA-enhanced twophoton excited fluorescence that allows highcontrast illumination of the nucleus.

Charge transfer complexes are interfacial charge pairs residing at the donor-acceptor heterointerface in organic solar cell. Experimental evidence shows them to be crucial for the photovoltaic performance: both photocurrent and open circuit voltage depends on them. For charge generation and recombination, charge transfer complexes represent essential intermediate steps. Clearly, understanding the role of the charge transfer state is essential for an optimisation of organic solar cells.

Homochiral porous metal-organic frameworks (MOFs) are particularly attractive candidates as heterogeneous asymmetric catalysts and enantioselective adsorbents and separators for production of optically active organic compounds. This review summarizes the recent research progress in homochiral MOF materials, including their synthetic strategy, distinctive structural features and applications in enantioselective catalysis and separation.

Ag-capped Au nanopillar arrays on a resin supporter (see left upper figure), with a typical adjacent pillar tip gap of 10 nm, show obviously higher surface-enhanced Raman scattering (SERS) sensitivity (right column in red) than that of the bare Au nanopillar array while using 10 nM R6G as probe molecules. The large-area Ag-capped Au nanopillar array has potential in trace detection of special chemicals.

A novel growth method (carbon molecular beam epitaxy (CMBE)) has been developed to produce high-quality and large-area epitaxial graphene. This method demonstrates significantly improved controllability of the graphene growth. CMBE with C₆₀ produces AB stacked graphene, while growth with the graphite filament results in non-Bernal stacked graphene layers with a Dirac-like electronic structure, which is similar to graphene grown by thermal decomposition on SiC (000-1).

Drug-loadingmesoporous silica nanoparticles that serve as a nanoreservoir-type drug-delivery system are successfully attached to titanium substrates via the layer-by-layer assembly technique (see scheme). The obtained structure demonstrates great potential for regulating the biological behaviors of osteoblasts/ steoclasts in order to maintain bone homeostasis. The approach we present here may have wide applications in implant technology, tissue engineering, and regenerative medicine.

Individual ZrS₂-nanobelt field-effect transistors were fabricated using a photolithography process. Temperature-dependent electrical transport revealed different electrical conductivity mechanism at different working temperature regions. ZrS₂-nanobelt photodetectors demonstrated a high-performance visible-light photoconductivity.

A photoluminescence (PL)-based oxygen and glucose sensor utilizing inorganic or organic light emitting diode as the light source, and polythiophene:fullerene type bulk-heterojunction devices as photodetectors, for both intensity and decay-time based monitoring of the sensing element’s PL. The sensing element is based on the oxygen-sensitive dye Pt-octaethylporphyrin embedded in a polystyrene matrix.

The in situ crystallization of the incorporated amorphous semiconductor within the multimaterial fiber device yields a large decrease in defect density and a concomitant five-order-of-magnitude decrease in resistivity of the novel metal-insulator-crystalline semiconductor structure. Using a post-drawing crystallization process, the first tens-of-meters-long single-fiber field-effect device is demonstrated. This work opens significant opportunities for incorporating higher functionality in functional fibers and fabrics.

Blue light: Incorporation of two fluorenyl rings into a phenyl group at the C9 position of fluorene builds a bulky and rigidly tetrahedral framework, which is functionalized by two carbazole groups. This molecule possesses excellent thermal and morphological stability, miscibility to the phosphorescent dopant, and high triplet energy, leading to narrow blue phosphorescent emission.

Quasi-periodic colloidal networks are constructed on the basis of polymorphic meniscus convergence (MC) in an air-cavity-embedded, nano-colloidal system. Depending on the flow associated with the air-cavities, the colloidal particles are self-organized into nanowires through binary MC, Y-junctions through ternary MC, and X-junctions through quaternary MC. The colloidal networks in either square or hexagonal form reflect the flow symmetry according to the air-cavity deformation.

Organization and patterning of zeolite L crystals with their unique properties such as their one-dimensional nano channel system is of highest topical interest with various applications in many areas of science. We demonstrate full three-dimensional optical control of single zeolite L crystals and for the first time fully reversible, dynamic organization of a multitude of individually controlled zeolite L crystals.

A nanocavity structure is embedded inside a silicon logpile photonic crystal that demonstrates tunable absorption behavior at near visible wavelengths well beyond the absorption edge of silicon. This is due to silicon’s indirect bandgap resulting in a relatively slow increase in the absorption of silicon with decreasing wavelength. Our results open up the possibility of utilizing the wide, complete three dimensional photonic gap enabled by the large refractive index of silicon to create three dimensional photonic crystal based devices well into the visible regime.

A water-soluble organic/inorganic hybrid nanodot based on polyhedral oligomeric silsesquioxane (POSS) and conjugated oligoelectrolyte is designed and synthesized for two-photon fluorescence imaging of cellular nucleus, which takes advantage of its small size (∼3.3 nm) that imparts nucleus permeability and substantial DNA-enhanced two-photon excited fluorescence that allows illuminating the nucleus with a high contrast.

Strategies for synthesizing of nanoscale single or bimetallic lanthanide metal-organic framework (MOF) materials and their transformation into Eu_1-xTb_x-MOF thin films are reported. The thin films prepared via spin coating deposition method are smooth, dense and mechanically stable. They also exhibit marked luminescent properties and efficient Tb³⁺-to-Eu³⁺ energy transferability.

Identically configured bulk heterojunction organic solar cells based on merocyanine dye donor and fullerene acceptor compounds (see figure) are manufactured either from solution or by vacuum deposition, to enable a direct comparison. Whereas the former approach is more suitable for screening purposes, the latter approach affords higher short-circuit current density and power conversion efficiency.

Solution prepared single crystal organic field-effect transistors (OFETs) combine low-cost with high performance due to structural ordering of molecules. However, in organic crystals polymorphism is a known phenomenon, which can have a crucial influence on charge transport. Here, the performance of solution-prepared single crystal OFETs based on two different polymorphs of dithiophene-tetrathiafulvalene, which were investigated by confocal Raman spectroscopy and X-ray diffraction, are reported. OFET devices prepared using different configurations show that both polymorphs exhibited excellent device performance, although the α-phase revealed charge carrier mobility between two and ten times higher in accordance to the closer stacking of the molecules.

We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors of pentacene and C₆₀, with bottom-contact mobilities of > 0.5 and > 1 cm² V⁻¹ s⁻¹, respectively. This represents a clear step towards development of inexpensive, high-performance all-organic circuits.