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Herein, we report the successful application of hybrid Au-Ag nanoparticles (NPs) and nanochains (NCs) in the harvesting of visible light energy for selective hydrogenation reactions. For individual Au@Ag NPs with Au25 cores, the conversion and turnover frequency (TOF) are approximately 8 and 10 times higher than those of Au25 NPs, respectively. Notably, after the self-assembly of the Au@Ag NPs, the conversion and TOF of 1D NCs were approximately 2.5 and 2 times higher than those of isolated Au@Ag NPs, respectively, owing to the coupling of surface plasmon and the increase in the rate at which hot (energetic) electrons are generated with the formation of plasmonic hot spots between NPs. Furthermore, the surface-enhanced Raman scattering (SERS) activity of 1D Au@Ag NCs was strengthened by nearly 2 orders of magnitude. [ABSTRACT FROM AUTHOR]

Lignin is a natural, renewable biopolymer synthesized by plants. It is a macromolecule consisting of aromatic structures with high density of functional groups making it an ideal precursor for the design of sustainable biomaterials for applications such as drug delivery. The rational design of these materials requires an in-depth understanding of the underlying lignin self-assembly in solution. Colloidal transformations from nanosized lignin assemblies to submicron-sized spherical particles upon solvent exchange were studied using small-angle X-ray scattering, dynamic light scattering, and electron microscopy. The surface fractal structure and stability of these particles was found to be strongly solvent and pH dependent, with aggregation to a gel-like material at low pH. The results may have important implications for the design of nanostructured lignin-based functional materials for consideration in various fields such as food science and biomedicine. [ABSTRACT FROM AUTHOR]

For the next generation of safe and high energy rechargeable lithium metal batteries, we introduce nanostructured polymer particles of asymmetric miktoarm star copolymers as additives to liquid electrolytes for use as solid polymer electrolytes (SPE). The mechanical properties of the resulting SPEs are dramatically improved compared to the pure liquid electrolyte (the elastic modulus increased by up to 8 orders of magnitude), while the ionic conductivity was maintained close to that of the pure liquid electrolyte. In particular, the addition of 44 wt % miktoarm stars, composed of ion conducting poly(ethylene oxide), PEO, arms that complement stiff insulating polystyrene arms, PS ((PS)n(PEO)n, where n = 30 the number of arms), in a low molecular weight PEO doped with lithium bis(trifluoromethane)sulfonamide (LiTFSI), resulted in SPEs with a shear modulus of G' ~ 0.1 GPa and ion conductivity σ ~ 10-4 S/cm. The SPEs show a strong decoupling between the mechanical behavior and the ionic conductivity as G' remains fairly constant for temperatures up to the glass transition temperature of the PS blocks, while the conductivity monotonically increases reaching σ ~ 10-2 S/cm. Our strategy offers tremendous potential for the design of all-polymer nanostructured materials with optimized mechanical properties and ionic conductivity over a wide temperature window for advanced lithium battery technology. [ABSTRACT FROM AUTHOR]

A new approach for constant-distance mode mass spectrometry imaging (MSI) of biological samples using nanospray desorption electrospray ionization (nano-DESI) was developed by integrating a shear-force probe with the nano-DESI probe. The technical concept and basic instrumental setup, as well as the general operation of the system are described. Mechanical dampening of resonant oscillations due to the presence of shear forces between the probe and the sample surface enabled the constant-distance imaging mode via a computer-controlled closed-feedback loop. The capability of simultaneous chemical and topographic imaging of complex biological samples is demonstrated using living Bacillus subtilis ATCC 49760 colonies on agar plates. The constant-distance mode nano-DESI MSI enabled imaging of many metabolites, including nonribosomal peptides (surfactin, plipastatin, and iturin) on the surface of living bacterial colonies, ranging in diameter from 10 to 13 mm, with height variations up to 0.8 mm above the agar plate. Co-registration of ion images to topographic images provided higher-contrast images. Based on this effort, constant-mode nano-DESI MSI proved to be ideally suited for imaging biological samples of complex topography in their native states. [ABSTRACT FROM AUTHOR]

Delamination is a key step to obtain individual layers from inorganic layered materials needed for fundamental studies and applications. For layered van der Waals materials such as graphene, the adhesion forces are small, allowing for mechanical exfoliation, whereas for ionic layered materials such as layered silicates, the energy to separate adjacent layers is considerably higher. Quite counterintuitively, we show for a synthetic layered silicate (Na0.5-hectorite) that a scalable and quantitative delamination by simple hydration is possible for high and homogeneous charge density, even for aspect ratios as large as 20000. A general requirement is the separation of adjacent layers by solvation to a distance where layer interactions become repulsive (Gouy-Chapman length). Further hydration up to 34 nm leads to the formation of a highly ordered lamellar liquid crystalline phase (Wigner crystal). Up to eight higher-order reflections indicate excellent positional order of individual layers. The Wigner crystal melts when the interlayer separation reaches the Debye length, where electrostatic interactions between adjacent layers are screened. The layers become weakly charge-correlated. This is indicated by fulfilling the classical Hansen-Verlet and Lindeman criteria for melting. We provide insight into the requirements for layer separation and controlling the layer distances for a broad range of materials and outline an important pathway for the integration of layers into devices for advanced applications. [ABSTRACT FROM AUTHOR]

Herein, we synthesized a series of 10 core-shell silver-silica nanoparticles with a photosensitizer, Rose Bengal, tethered to their surface. Each nanoparticle possesses an identical silver core of about 67 nm, but presents a different silica shell thickness ranging from 5 to 100 nm. These hybrid plasmonic nanoparticles thus afford a plasmonic nanostructure platform with a source of singlet oxygen (1O2) at a well-defined distance from the metallic core. Via time-resolved and steady state spectroscopic techniques, we demonstrate the silver core exerts a dual role of enhancing both the production of ¹O2, through enhanced absorption of light, and its radiative decay, which in turn boosts ¹O2 phosphorescence emission to a greater extent. Furthermore, we show both the production and emission of ¹O2 in vitro to be dependent on proximity to the plasmonic nanostructure. Our results clearly exhibit three distinct regimes as the plasmonic nanostructure moves apart from the ¹O2 source, with a greater enhancement for silica shell thicknesses ranging between 10 and 20 nm. Moreover, these hybrid plasmonic nanoparticles can be delivered to both Gram-positive and Gram-negative bacteria boosting both photoantibacterial activity and detection limit of ¹O2 in cells. [ABSTRACT FROM AUTHOR]

The self-assembly of structures with "addressable complexity", where every component is distinct and is programmed to occupy a specific location within a target structure, is a promising route to engineering materials with precisely defined morphologies. Because systems with many components are inherently complicated, one might assume that the chances of successful selfassembly are extraordinarily small. Yet recent advances suggest otherwise: addressable structures with hundreds of distinct building blocks have been designed and assembled with nanometer precision. Despite this remarkable success, it is often challenging to optimize a self-assembly reaction to ensure that the intended structure is kinetically accessible. In this Perspective, we focus on the prediction of kinetic pathways for self-assembly and implications for the design of robust experimental protocols. The development of general principles to predict these pathways will enable the engineering of complex materials using a much wider range of building blocks than is currently possible. [ABSTRACT FROM AUTHOR]

Peptide-enabled nanoparticle (NP) synthesis routes can create and/or assemble functional nanomaterials under environmentally friendly conditions, with properties dictated by complex interactions at the biotic/abiotic interface. Manipulation of this interface through sequence modification can provide the capability for material properties to be tailored to create enhanced materials for energy, catalysis, and sensing applications. Fully realizing the potential of these materials requires a comprehensive understanding of sequence-dependent structure/function relationships that is presently lacking. In this work, the atomic-scale structures of a series of peptidecapped Au NPs are determined using a combination of atomic pair distribution function analysis of high-energy X-ray diffraction data and advanced molecular dynamics (MD) simulations. The Au NPs produced with different peptide sequences exhibit varying degrees of catalytic activity for the exemplar reaction 4-nitrophenol reduction. The experimentally derived atomicscale NP configurations reveal sequence-dependent differences in structural order at the NP surface. Replica exchange with solute-tempering MD simulations are then used to predict the morphology of the peptide overlayer on these Au NPs and identify factors determining the structure/catalytic properties relationship. We show that the amount of exposed Au surface, the underlying surface structural disorder, and the interaction strength of the peptide with the Au surface all influence catalytic performance. A simplified computational prediction of catalytic performance is developed that can potentially serve as a screening tool for future studies. Our approach provides a platform for broadening the analysis of catalytic peptide-enabled metallic NP systems, potentially allowing for the development of rational design rules for property enhancement. [ABSTRACT FROM AUTHOR]

The athors respond to the comment on their study about accurate data process for nanopore analysis. Topics discussed include a description of second-order-differential-based calibration method used in the study, the pulse train model, and the use of the Fourier series in fitting the time series data.

A controlledassembly and alignment of carbon nanotubes (CNTs) in a high-packingdensity with a scalable way remains challenging. This paper focuseson the preparation of self-assembled and well-aligned CNTs with adensely packed nanostructure in the form of buckypaper via a simplefiltration method. The CNT suspension concentration is strongly reflectedin the alignment and assembly behavior of CNT buckypaper. We furtherdemonstrated that the horizontally aligned CNT domain gradually increasesin size when increasing the deposited CNT quantity. The resultantaligned buckypaper exhibited notably enhanced packing density, strength,modulus, and hardness compared to previously reported buckypapers. [ABSTRACT FROM AUTHOR]

Increasinglithium content is shown to be a successful strategy for designingnew cathode materials. In layered LixNi2–4x/3Sbx/3O2(x= 1.00–1.15), lithium excessimproves both discharge capacity and capacity retention at 1C. Structuralstudies reveal a complex nanostructure pattern of Li–Sb andNi–Sb ordering where the interface between these domains formsthe correct local configuration for good lithium mobility. The <1nm Li–Sb stripe domains and their interfaces thereby effectivelyact as nanohighways for lithium diffusion. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) hexagonal boronnitride (BN) nanosheets are excellent dielectric substrate for graphene,molybdenum disulfide, and many other 2D nanomaterial-based electronicand photonic devices. To optimize the performance of these 2D devices,it is essential to understand the dielectric screening propertiesof BN nanosheets as a function of the thickness. Here, electric forcemicroscopy along with theoretical calculations based on both state-of-the-artfirst-principles calculations with van der Waals interactions underconsideration, and nonlinear Thomas–Fermi theory models areused to investigate the dielectric screening in high-quality BN nanosheetsof different thicknesses. It is found that atomically thin BN nanosheetsare less effective in electric field screening, but the screeningcapability of BN shows a relatively weak dependence on the layer thickness. [ABSTRACT FROM AUTHOR]

Inthis Letter, we report the preparation of sulfur nanodots (2nm average) electrodeposited on flexible nickel foam and their applicationas high-performance cathode of Li–S batteries. An electrodepostionmethod was applied to prepare the cathode at room temperature andthe sulfur mass was controllable from 0.21 to 4.79 mg/cm2in a large area of over 100 cm2. The optimized cathodewith 0.45 mg/cm2S on Ni foam displayed high initial dischargecapacity (1458 mAh/g at 0.1 C), high rate capability (521 mAh/g at10 C), and long cycling stability (895 mAh/g after 300 cycles at 0.5C and 528 mAh/g after 1400 cycles at 5 C). Moreover, in situ Ramanand transmission electron microscopy analysis demonstrated the fundamentalsof reversible electrochemical reaction between S and Li2S nanodots. This fast, facile, and one-step cathode preparation methodwith excellent electrochemical performance will lead to technologicaladvances of S cathode in Li–S batteries. [ABSTRACT FROM AUTHOR]

Inthis study, a simple and systematic shape-controlled syntheticprotocol for tailoring nanoscale structures to generate large andmonodispersed of three-dimensional (3D) urchin-like Pt–Ni multipods(MPs) and spherical nanoparticles (NPs) is reported, for which themechanism of production is elaborated in detail. We then demonstrate,for the first time, that the 3D urchin-like Pt–Ni MPs possessgood solution processability and substantially enhance both short-circuitcurrent density (Jsc) and fill factor(FF) and consequently increase the overall power conversion efficiencies(PCEs), because of the combination of multiple scattering processesof incident light, improved conductivity, and facilitating the chargetransport in the active layer. PSC fabricated using 5% Pt–NiMPs embedded in a blend of poly{[4,8-bis(2-ethyl-hexyl-thiophene-5-yl)-benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl]-alt-[2-(2′-ethyl-hexanoyl)-thieno[3,4-b]thiophen-4,6-diyl]} (PBDTTT-C-T) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) leads to compellingdevice PCEs of 8.48%, in comparison to 7.38% of the reference device(PBDTTT-C-T:PC71BM, fabricated and tested under the sameconditions). This study thus demonstrates a novel approach to enhancethe photovoltaic performance, in combination with 3D urchin-like nanoalloys. [ABSTRACT FROM AUTHOR]

The challenge of constructing soft functional materials over multiplelength scales can be addressed by a number of different routes basedon the principles of self-assembly, with the judicious use of variousnoncovalent interactions providing the tools to control such self-assemblyprocesses. It is within the context of this challenge that we haveextensively explored the use of an important approach for materialsconstruction over the past decade: exploiting electrostatic interactionsin our ionic self-assembly (ISA) method. In this approach, cooperativeassembly of carefully chosen charged surfactants and oppositely chargedbuilding blocks (or tectons) provides a facile noncovalent route forthe rational design and production of functional nanostructured materials.Generally, our research efforts have developed with an initial focuson establishing rules for the construction of novel noncovalent liquid-crystalline(LC) materials. We found that the use of double-tailed surfactantspecies (especially branched double-tailed surfactants) led to thefacile formation of thermotropic (and, in certain cases, lyotropic)phases, as demonstrated by extensive temperature-dependent X-ray andlight microscopy investigations. From this core area of activity,research expanded to cover issues beyond simple construction of anisotropicmaterials, turning to the challenge of inclusion and exploitationof switchable functionality. The use of photoactive azobenzene-containingISA materials afforded opportunities to exploit both photo-orientationand surface relief grating formation. The preparation of these anisotropicLC materials was of interest, as the aim was the facile productionof disposable and low-cost optical components for display applicationsand data storage. However, the prohibitive cost of the photo-orientationprocesses hampered further exploitation of these materials. We alsoexpanded our activities to explore ISA of biologically relevant tectons,specifically deoxyguanosine monophosphate. This approach proved, incombination with block copolymer (BCP) self-assembly, very fruitfulfor the construction of complex and hierarchical functional materialsacross multiple length scales. Molecular frustration and incommensurability,which played a major role in structure formation in combination withnucleotide assembly, have now become important tools to tune supramolecularstructure formation. These concepts, that is, the use of BCP assemblyand incommensurability, in combination with metal-containing polymericmaterials, have provided access to novel supramolecular morphologiesand, more importantly, design rules to prepare such constructs. Thesedesign rules are now also being applied to the assembly of electroactiveoligo(aniline)-based materials for the preparation of highly orderedfunctional soft materials, and present an opportunity for materialsdevelopment for applications in energy storage. In this Account, wetherefore discuss investigations into (i) the inclusion and preparationof supramolecular photoactive and electroactive materials; (ii) theexploitation and control over multiple noncovalent interactions tofine-tune function, internal structure, and long-range order and (iii)exploration of construction over multiple length scales by combinationof ISA with well-known BCP self-assembly. Combination of ISA withtuning of volume fractions, mutual compatibility, and molecular frustrationnow provides a versatile tool kit to construct complex and hierarchicalfunctional materials in a facile noncovalent way. A direct challengefor future ISA activities would certainly be the construction of functionalmesoscale objects. However, within a broader scientific context, thechallenge would be to exploit this powerful assembly tool for applicationin areas of research with societal impact, for example, energy storageand generation. The hope is that this Account will provide a platformfor such future research activities and opportunities. [ABSTRACT FROM AUTHOR]

Nanomaterials have revolutionized modem science and technology due to their multiple applications in engineering, physics, chemistry, and biomedicine. Nevertheless, the use and manipulation of nanoparticles (NPs) can bring serious damages to living organisms and their ecosystems. For this reason, ecotoxicity and cytotoxicity assays are of special interest in order to determine the potential harmful effects of NPs. Processes based on ecotoxicity and cytotoxicity tests can significantly consume time and financial resources. In this sense, alternative approaches such as quantitative structure--activity/toxicity relationships (QSAR/QSTR) modeling have provided important insights for the better understanding of the biological behavior of NPs that may be responsible for causing toxicity. Until now, QSAR/QSTR models have predicted ecotoxicity or cytotoxicity separately against only one organism (bioindicator species or cell line) and have not reported information regarding the quantitative influence of characteristics other than composition or size. In this work, we developed a unified QSTR perturbation model to simultaneously probe ecotoxicity and cytotoxicity of NPs under different experimental conditions, including diverse measures of toxicities, multiple biological targets, compositions, sizes and conditions to measure those sizes, shapes, times during which the biological targets were exposed to NPs, and coating agents. The model was created from 36488 cases (NP-NP pairs) and exhibited accuracies higher than 98% in both training and prediction sets. The model was used to predict toxicities of several NPs that were not included in the original data set. The results of the predictions suggest that the present QSTR-perturbation model can be employed as a highly promising tool for the fast and efficient assessment of ecotoxicity and cytotoxicity of NPs. [ABSTRACT FROM AUTHOR]

Using pruned-enriched Rosenbluthmethod (PERM) simulations of adiscrete wormlike chain model, we provide compelling evidence in supportof Odijk’s prediction of two distinct Odijk regimes for a longwormlike chain confined in a nanochannel. In both cases, the chainof persistence length lpis renormalizedinto a series of deflection segments of characteristic length D2/3lp1/3, where Dis the channel size. In the first (classic) Odijk regime, thesedeflection segments are linearly ordered. In the second Odijk regime,thin, long wormlike chains can backfold at a length scale quantifiedby the global persistence length. We have measured this quantity bysimulations and modified Odijk’s global persistence lengththeory to account for thermal fluctuations. The global persistencelength, which is defined to be independent of the effect of excludedvolume, provides the requisite closure to Odijk’s scaling theoryfor the second regime and thus allows us to resolve much of the confusionsurrounding the so-called “transition” regime for DNAconfined in a nanochannel. We show that Odijk’s theory forthe backfolded regime correctly describes both the average chain extensionand the variance about this extension for wormlike chains in channelsizes between the classic Odijk regime and the de Gennes blob regimes,with our data spanning several decades in terms of Odijk’sscaling parameter ξ. Although the backfolded Odijk regime occupiesa very narrow range of D/lp, it is indeed a regime when viewed in terms of ξ and growsin size with increasing monomer anisotropy. [ABSTRACT FROM AUTHOR]

Electridesare ionic crystals in which the anionic electrons areconfined to interstitial subnanometer-sized spaces. At present, thereported electrides only consist of main-group elements. Here, wereport a layered-structure transition-metal hypocarbide electride,Y2C, with quasi-two-dimensional (quasi-2D) anionic electronsconfined in the interlayer space. Physical properties measurementsreveal polycrystalline Y2C exhibits semimetallic behavior,and paramagnetism with an effective magnetic moment of ∼0.6μB/Y, because of the existence of localized d-electrons.Photoelectron spectroscopy measurements illustrate the work functionof polycrystalline Y2C is 2.9 eV, lower than Y metal, revealingthe loosely bound nature of the anionic electrons. Density functionaltheory calculations indicate the density of states at the Fermi leveloriginates from the states at interstitial sites and the Y 4d-orbitals,supporting the confinement of anionic electrons within the interlayerspace. These results demonstrate that Y2C is a quasi-2Delectride in term of [Y2C]1.8+·1.8e–, and the coexistence of the anionic electrons andthe Y 4d-electrons leads to the semimetallic behavior. [ABSTRACT FROM AUTHOR]

Nanostructuredliquid-crystalline (LC) ion transporters have beendeveloped and applied as new electrolytes for dye-sensitized solarcells (DSSCs). The new electrolytes are two-component liquid crystalsconsisting of a carbonate-based mesogen and an ionic liquid that self-assembleinto two-dimensional (2D) nanosegregated structures forming well-definedionic pathways suitable for the I–/I3–redox couple transportation. These electrolytesare nonvolatile and they show LC phases over wide temperature ranges.The DSSCs containing these electrolytes exhibit exceptional open-circuitvoltages (Voc) and improved power conversionefficiencies with increasing temperature. Remarkably, these solarcells operate at temperatures up to 120 °C, which is, to thebest of our knowledge, the highest working temperature reported fora DSSC. The nature of the LC electrolyte and the interactions at theTiO2electrode/electrolyte interface lead to a partialsuppression of electron recombination reactions, which is key in theexceptional features of these LC-DSSCs. Thus, this type of solar cellsare of interest, because they can produce electricity efficientlyfrom light at elevated temperatures. [ABSTRACT FROM AUTHOR]

Wepresent metallic nanohole arrays fabricated on suspended membranesas an optofluidic substrate. Millimeter-sized suspended nanohole arrayswere fabricated using nanoimprint lithography. We demonstrate refractive-index-basedtuning of the optical spectra using a sucrose solution for the optimizationof SERS signal intensity, leading to a Raman enhancement factor of107. Furthermore, compared to dead-ended nanohole arrays,suspended nanohole arrays capable of flow-through detection increasedthe measured SERS signal intensity by 50 times. For directed transportof analytes, we present a novel methodology utilizing surface tensionto generate spontaneous flow through the nanoholes with flow ratesof 1 μL/min, obviating the need for external pumps or microfluidicinterconnects. Using this method for SERS, we obtained a 50 timeshigher signal as compared to diffusion-limited transport and coulddetect 100 pM 4-mercaptopyridine. The suspended nanohole substratespresented herein possess a uniform and reproducible geometry and showthe potential for improved analyte transport and SERS detection. [ABSTRACT FROM AUTHOR]

Thestability and hydrodynamic size of ligand-coated gold nanorods(GNRs; aspect ratio 3.6) have been characterized by nanoparticle trackinganalysis (NTA)a single-particle counting method that can measuresize distributions with low nanometer resolution. Stable aqueous suspensionsof citrate-stabilized GNRs (cit-GNRs) are amenable to surface functionalizationwithout loss of dispersion control. Cit-GNRs can be treated with chemisorptiveligands (thiols and dithiocarbamates), nonionic surfactants (Tween20), and proteins (human serum albumin), all of which produce stablesuspensions at low surfactant concentrations. The precision of NTA(relative standard deviation 10–12%, standard error <2%)is sufficient to allow differences in the hydrodynamic size of coatedGNRs to be interpreted in terms of surfactant structure and conformation. [ABSTRACT FROM AUTHOR]

Emulsions, solid lipid nanoparticles(SLN), and nanostructured lipid carriers (NLC) containing a mix ofliquid and solid domains are of interest as encapsulation vehiclesfor hydrophobic compounds. Studies of the release rate from theseparticles yield contradictory results: Some find that increasing thefraction of solid phase increases the rate of release and others theopposite. In this paper we study the release of encapsulated materialsfrom lipid-based nanoparticles using Monte Carlo simulations. We findthat, quite surprisingly, the release rate is largely insensitiveto the size of solid domains or the fraction of solid phase. However,the distribution of the domains significantly affects the rate ofrelease: Solid domains located at the interface with the surroundingsolution inhibit transport, while nanoparticles where the solid domainsare concentrated in the center enhance it. The latter can lead torelease rates in NLCs that are faster than in the equivalent emulsions.We conclude that controlling the release rate from NLCs requires theability to determine the location and distribution of the solid phase,which may be achieved through choice of the surfactants stabilizingthe particles, incorporation of nucleation sites, and/or the coolingrates and temperatures. [ABSTRACT FROM AUTHOR]

NanostructuredTiO2thin films were fabricated via afacile, economical, and energy-efficient microwave-assisted dip-coating(MWDC) technique. Further, the resulting TiO2films werecharacterized by means of X-ray diffraction, high-resolution transmissionelectron microscopy, selected-area electron diffraction, Fourier transformRaman spectroscopy, X-ray photoelectron spectroscopy, and photoluminescencespectroscopy techniques for their phase structure, morphology, andoptical and surface properties. TiO2-mediated photoelectrocatalyticdegradation of the antibiotic cefotaxime (CFX) in an aqueous solutionwas studied by varying the pH under UV illumination. The degradationintermediates and possible reaction degradation path of CFX were analyzedby electrospray ionization time-of-flight mass spectrometry (MS).The MS spectra revealed that degradation of CFX occurs through β-lactumcorresponding to the cleavage of the cephem nucleus. Moreover, theantibacterial activity of CFX prior to and after photoelectrocatalyticdegradation was carried out to analyze the toxicity against Staphylococcus aureusand salmonella typhi bacteria. Interestingly,it was observed that the antibiotic activity was drastically inhibitedafter photoelectrocatalytic degradation of the CFX solution. The photoelectrocatalyticstability of a nanostructured TiO2electrode was evaluatedby recycling the degradation experiments. It was observed that therewas no significant decrease in the catalytic activity, indicatingpotential applications of the TiO2electrode prepared bythe MWDC method. [ABSTRACT FROM AUTHOR]

Direct analysis in real time mass spectrometry (DART-MS) is used to analyze the surface chemical composition of nanometer-sized organic aerosol partides in real time at atmospheric pressure. By introducing a stream of partides in between the DART ionization source and the atmospheric pressure inlet of the mass spectrometer, the aerosol is exposed to a thermal flow of helium or nitrogen gas containing some fraction of metastable helium atoms or nitrogen molecules, in this configuration, the molecular constituents of organic partides are desorbed, ionized, and detected with reduced molecular ion fragmentation, allowing for compositional identification. Aerosol particles detected include alkanes, alkenes, acids, esters, alcohols, aldehydes, and amino acids. The ion signal produced by DART-MS scales with the aerosol surface area rather than volume, suggesting that DART-MS is a viable technique to measure the chemical composition of the partide interface. For oleic acid, particle size measurements of the aerosol stream exiting the ionization region suggest that the probing depth depends upon the desorption temperature, and the probing depth is estimated to be on the order of S nm for a 185 run diameter partide at a DART heater temperature of 500 °C with nitrogen as the DART gas. The reaction of ozone with submicrometer oleic acid particles is measured to demonstrate the ability of this technique to identify products and quantify reaction rates in a heterogeneous reaction. [ABSTRACT FROM AUTHOR]

Single-layer single-crystalline SnSe nanosheet with four-atomic thickness of ~1.0 nm and lateral size of ~300 nm is presented here by using a one-pot synthetic method. It is found that 1,10-phenanthroline plays an important role in determining the morphology of the SnSe product as three-dimensional SnSe nanoflowers are obtained in the absence of 1,10-phenanthroline while keeping other reaction parameters the same. The evolution process study discloses that single-crystalline nanosheets are obtained from the coalescence of the SnSe nucleus in an orientated attachment mechanism. Band gap determination and optoelectronic test based on hybrid films of SnSe and poly(3-hexylthiophene) indicate the great potential of the ultrathin SnSe nanosheets in photodector and photovoltaic, and so forth. [ABSTRACT FROM AUTHOR]

We have investigated in detail the effect of CdS and ZnS as second phases on the thermoelectric properties of p-type PbS. We report a ZT of 1.3 at 923 K for 2.5 at.% Na-doped p-type PbS with endotaxially nanostructured 3.0 at.% CdS. We attribute the high ZT to the combination of broad-based phonon scattering on multiple length scales to reduce (lattice) thermal conductivity and favorable charge transport through coherent interfaces between the PbS matrix and metal sulfide nanophase precipitates, which maintains the requisite high carrier conductivity and the associated power factor. Similar to large ionically bonded metal sulfides (ZnS, CaS, and SrS), the covalently bonded CdS can also effectively reduce the lattice thermal conductivity in p-type PbS. The presence of ubiquitous nanostructuring was confirmed by transmission electron microscopy. Valence and conduction band energy levels of the NaCl-type metal sulfides, MS (M = Pb, Cd, Zn, Ca, and Sr) were calculated from density functional theory to gain insight into the band alignment between PbS and the second phases in these materials. The hole transport is controlled by band offset minimization through the alignment of valence bands between the host PbS and the embedded second phases, MS (M = Cd, Zn, Ca, and Sr). The smallest valence band offset of about 0.13 eV at 0 K was found between PbS and CdS which is diminished further by thermal band broadening at elevated temperature. This allows carrier transport between the endotaxially aligned components (i.e., matrix and nanostructure), thus minimizing significant deterioration of the hole mobility and power factor. We conclude the thermoelectric performance of the PbS system and, by extension, other systems can be enhanced by means of a closely coupled phonon-blocking/electron-transmitting approach through embedding endotaxially nanostructured second phases. [ABSTRACT FROM AUTHOR]

Copper nanomaterials are being used in a large number of commercial products because these materials exhibit unique optical, magnetic, and electronic properties. Metallic copper nanoparticles, which often have a thin surface oxide layer, can age in the ambient environment and become even more oxidized over time. These aged nanoparticles will then have different properties compared to the original nanoparticles. In this study, we have characterized three different types of copper-based nanoparticle (NP) samples designated as Cu(new) NPs, Cu(aged) NPs, and CuO NPs that differ in the level of oxidation. The solution phase behavior of these three copper-based nanoparticle samples is investigated as a function of pH and in the presence and absence of two common, complexing organic acids, citric and oxalic acid. The behavior of these three copper-based NP types shows interesting differences. In particular, Cu(aged) NPs exhibit unique chemistry including oxide phases that form and surface adsorption properties. Overall, the current study provides some insights into the impacts of nanoparticle aging and how the physicochemical characteristics and reactivity of nanomaterials can change upon aging. [ABSTRACT FROM AUTHOR]

The article comments on a study by Z. Gu and colleagues on accurate data process for nanopore analysis. Topics discussed include the challenge with nanopores, the method proposed by the authors that is focused on recovering information from fast events recorded with a biological nanopore, and the use of the Fourier series in fitting the time series data.

We describe monolayer nanosheets of calcium copper tetrasilicate, CaCuSi4O10, which have strong near-IR luminescence and are amenable to solution processing methods. The facile exfoliation of bulk CaCuSi4O10 into nanosheets is especially surprising in view of the long history of this material as the colored component of Egyptian blue, a well-known pigment from ancient times. [ABSTRACT FROM AUTHOR]