Skip to content. Skip to navigation
Personal tools
You are here: Home
Featured Journal
Site Search
Search only the current folder (and sub-folders)
Log in

Forgot your password?
New user?
Check out our New Publishers' Select for Free Articles
Journal Search

Journal of Materials Chemistry (v.21, #39)

Front cover (pp. 15065-15065).
An optimised procedure was developed for the layer-by-layer deposition of the Hofmann clathrate-like coordination compound {Fe(pyrazine)[Pt(CN)4]} either as continuous or as nano-patterned thin films. Characterization of the thickness and topography of the thin films by atomic force microscopy (AFM) and by surface plasmon resonance (SPR) spectroscopy, which also yields the layer's refractive index and losses, are reported. We found that the films are of good optical quality and the results of both AFM and SPR experiments are in good agreement with the theoretical predictions of the films thicknesses.

Inside front cover (pp. 15066-15066).
A novel protocol for nickel-catalyzed direct sp2 C–H bond arylation of purines has been developed. This new reaction proceeded efficiently at room temperature using Grignard reagent as the coupling partner within 5 hours in good to high yields. This approach provides a new access to a variety of C8-arylpurines which are potentially of great importance in medicinal chemistry.

Contents list (pp. 15067-15094).
Dynamic states of cancer cells moving under shear flow in an antibody-functionalized microchannel are investigated experimentally and theoretically. The cell motion is analyzed with the aid of a simplified physical model featuring a receptor-coated rigid sphere moving above a solid surface with immobilized ligands. The motion of the sphere is described by the Langevin equation accounting for the hydrodynamic loadings, gravitational force, receptor-ligand bindings, and thermal fluctuations; the receptor-ligand bonds are modeled as linear springs. Depending on the applied shear flow rate, three dynamic states of cell motion have been identified: (i) free motion, (ii) rolling adhesion, and (iii) firm adhesion. Of particular interest is the fraction of captured circulating tumor cells, defined as the capture ratio, via specific receptor-ligand bonds. The cell capture ratio decreases with increasing shear flow rate with a characteristic rate. Based on both experimental and theoretical results, the characteristic flow rate increases monotonically with increasing either cell-receptor or surface-ligand density within certain ranges. Utilizing it as a scaling parameter, flow-rate dependent capture ratios for various cell-surface combinations collapse onto a single curve described by an exponential formula.

Formation of complex nanostructures driven by polar surfaces by Huatao Wang; Tom Wu (pp. 15095-15099).
Here we highlight the recent advances in synthesizing some novel nanostructures where polar surfaces and the associated electrostatic interactions appear to play critical roles. Some examples, including ZnO nanospring and nanoring, AlN nanonecklace, and CrSi2 nanoweb, are discussed.

Amine-oxide hybrid materials for acid gas separations by Praveen Bollini; Stephanie A. Didas; Christopher W. Jones (pp. 15100-15120).
Organic–inorganic hybrid materials based on porous silica materials functionalized with amine-containing organic species are emerging as an important class of materials for the adsorptive separation of acid gases from dilute gas streams. In particular, these materials are being extensively studied for the adsorption of CO2 from simulated flue gas streams, with an eye towards utilizing these materials as part of a post-combustion carbon capture process at large flue gas producing installations, such as coal-fired electricity-generating power plants. In this Application Article, the utilization of amine-modified organic–inorganic hybrid materials is discussed, focusing on important attributes of the materials, such as (i) CO2 adsorption capacities, (ii) adsorption and desorption kinetics, and (iii) material stability, that will determine if these materials may one day be useful adsorbents in practical CO2 capture applications. Specific research needs and limitations associated with the current body of work are identified.

Medical applications of inorganic fullerene-like nanoparticles by A. R. Adini; M. Redlich; R. Tenne (pp. 15121-15131).
Nanoparticles of layered compounds, like MoS2 and WS2, having hollow closed-cage structures and known as fullerene-like (IF) and inorganic nanotubes (INT), are synthesized in macroscopic amounts. They were found to have superior tribological properties and can serve as solid-state additives to different lubrication fluids. More recently, metallic films incorporating the IF nanoparticles were prepared via wet deposition methods and also by physical vapor deposition techniques. The incorporation of the nanoparticles endows such coatings self-lubricating behavior, i.e. low friction and wear, which is highly desirable for variety of applications. The current feature article provides a short overview of the progress in the materials synthesis of IF and INT phases. Subsequently, a progress report of the various efforts to apply such coatings to medical devices and drug delivery is described.

Preparation and functionality of clay-containing films by Chun-Hui Zhou; Zhang-Feng Shen; Li-Hong Liu; Shao-Min Liu (pp. 15132-15153).
This article provides an insight into state-of-the-art advances in the preparation and functionalization of clay-containing thin films. Layered clay minerals and their synthetic counterparts such as cationic montmorillonite, saponite, laponite and anionic layered double hydroxides are often used as main components or functional fillers in the hybrid films. Strategic assembly of clay minerals or layered double hydroxides with functional molecules has led to a variety of nanostructured clay-containing hybrid films. Frequently used approaches are the solvent casting, the spin-coating, the layer-by-layer (LbL) assembly and the Langmuir–Blodgett (LB) techniques. The type of clay mineral, solvent, pH, organic components and functional molecules generally play a pivotal role in the formation and structure of a desired functional film. Different processes result in differences in the thickness, surface morphology and internal structure in the resultant clay-containing films. Functional polymers, dye molecules, transition metal complexes and protein molecules and even their combination have been exploited to fabricate and functionalize clay-containing films. Many studies have suggested that the functional clay-containing films have potential applications in many areas such as catalysis, modified electrodes and optoelectronic devices, anti-corrosion and packaging materials. Finally, the prospects for the future preparation and applications of clay-containing films are discussed.

Black thin layers generate strong structural colors: a biomimetic approach for creating one-dimensional (1D) photonic crystals by Hiroshi Yabu; Takayuki Nakanishi; Yuji Hirai; Masatsugu Shimomura (pp. 15154-15156).
We report a simple, novel method for obtaining structurally colored films consisting of poly(1,2-butadiene) (PB) and Os multi-layers that mimic the surface structure of jewel beetle elytra. Strong color reflection was achieved by interference of light at the interface between the multi-layers. Active control of the reflection peaks was achieved by swelling the PB layers with solvent, and photopatterning of the composite film was also performed.

Peptide functionalized superparamagnetic iron oxide nanoparticles as MRI contrast agents by Selim Sulek; Busra Mammadov; Davut I. Mahcicek; Huseyin Sozeri; Ergin Atalar; Ayse B. Tekinay; Mustafa O. Guler (pp. 15157-15162).
Magnetic resonance imaging (MRI) attracts great attention in cellular and molecular imaging due to its non-invasive and multidimensional tomographic capabilities. Development of new contrast agents is necessary to enhance the MRI signal in tissues of interest. Superparamagnetic iron oxide nanoparticles (SPIONs) are used as contrast agents for signal enhancement as they have revealed extraordinary magnetic properties at the nanometre size and their toxicity level is very low compared to other commercial contrast agents. In this study, we developed a new method to functionalize the surface of SPIONs. Peptide amphiphile molecules are used to coat SPIONs non-covalently to provide water solubility and to enhance biocompatibility. Superparamagnetic properties of the peptide–SPION complexes and their ability as contrast agents are demonstrated. In vitro cell culture experiments reveal that the peptide–SPION complexes are biocompatible and are localized around the cells due to their peptide coating.

α-(Y,Gd)FS:Ce3+: a novel red-emitting fluorosulfide phosphor for solid-state lighting by Yun-Chen Wu; Yi-Chin Chen; De-Yin Wang; Chi-Shen Lee; Ching-Cherng Sun; Teng-Ming Chen (pp. 15163-15166).
A novel Ce3+-doped fluorosulfide phosphor, α-(Y,Gd)FS:Ce3+, was first investigated as a new candidate for application in phosphor-converted light emitting diodes (LEDs) and thin-film electroluminescence (TFEL) devices. The detailed crystal structure was investigated based on X-ray diffraction profiles using Rietveld refinement methods. This phosphor shows good absorption ranging from ultraviolet to visible region and broad saturated red emission, which can be tuned from 660 to 672 nm, and the photoluminescence (PL) intensity was demonstrated to be effectively enhanced by Gd3+ substitution.

In situ formation and ordered assembly of gold nanoclusters to nano-ribbons at the oil/water interface by FuKe Wang; Xinhai Zhang; Zheng Zhang; Chaobin He (pp. 15167-15170).
Ordered assembly of ultra-small nanoparticles or nanoclusters remains a challenge due to their large surface energy induced ripening and isotropic aggregation. In this communication, an in situ formation and assembly of ultra-small gold nanoclusters at the oil/water interface was developed to assemble gold nanoclusters into well-defined nano-ribbon structures. The resulting nano-ribbons exhibited enhanced optical properties and larger Stokes's shift than those of random dispersed gold nanoclusters.

Efficient synthesis of polymeric g-C3N4 layered materials as novel efficient visible light driven photocatalysts by Fan Dong; Liwen Wu; Yanjuan Sun; Min Fu; Zhongbiao Wu; S. C. Lee (pp. 15171-15174).
In order to develop efficient visible light driven photocatalysts for environmental applications, novel polymeric g-C3N4 layered materials with high surface areas are synthesized efficiently from an oxygen-containing precursor by directly treating urea in air between 450 and 600 °C, without the assistance of a template for the first time. The as-prepared g-C3N4 materials with strong visible light absorption have a band gap around 2.7 eV. The crystallinity and specific surface areas of g-C3N4 increases simultaneously when the heating temperatures increases. The g-C3N4 materials are demonstrated to exhibit much higher visible light photocatalytic activity than that of C-doped TiO2 and g-C3N4 prepared from dicyanamide for the degradation of aqueous RhB. The large surface areas, layered structure and band structure in all contributed to the efficient visible light photocatalytic activity. The efficient synthesis method for g-C3N4 combined with efficient photocatalytic activity is of significant interest for environmental pollutants degradation and solar energy conversion in large scale applications.

Sculpting fabrication of nanocrater catalysts and exclusive control of wall numbers and diameters in carbon nanotubes by Kyung Min Choi; Saji Augustine; Young Min Kim; Ju Ho Lee; Jeong Yong Lee; Jeung Ku Kang (pp. 15175-15178).
We develop the sculpting method to synthesize well-defined nanocrater catalysts with the hollow core/metal shell structure within an array via chemical and plasma processes. Also, we successfully demonstrate that unique morphologies of nanocrater catalysts as effective templates allow the exclusive control of the number of walls and outer diameters in carbon nanotubes.

Facile synthesis of one dimensional graphene wrapped carbon nanotube composites by chemical vapour deposition by Sasidharannair Sasikaladevi Jyothirmayee Aravind; Varrla Eswaraiah; Sundara Ramaprabhu (pp. 15179-15182).
A unique method for synthesis of graphene wrapped carbon nanotubes was developed by chemical vapor deposition. Raman analyses show that defects have been created during growth which helps in the efficient dispersion of the composites in a variety of solvents. The synergistic combination of 2D graphene and 1D carbon nanotubes with high electrical conductivity (30 S m−1) can be exploited for energy and sensing applications.

Self-assembled red luminescent micelles and lamellar films by Fabian Niedermair; Kurt Stubenrauch; Andreas Pein; Robert Saf; Elisabeth Ingolić; Werner Grogger; Gerhard Fritz-Popovski; Gregor Trimmel; Christian Slugovc (pp. 15183-15185).
The supramolecular assembly of a non-luminescent cationic platinum complex with an amphiphilic block copolymer bearing free carboxylic acid moieties leads to a turn-on of red phosphorescence due to the formation of luminescent platinum complex aggregates guided by the carboxylic acid groups. This principle enables preparation of red-emitting spherical micelles and free-standing lamellar films.

Solution processed ter-anthrylene-ethynylenes for annealing-activated organic field-effect transistors: a structure–performance correlation study by Giuseppe Romanazzi; Antonio Dell'Aquila; Gian Paolo Suranna; Francesco Marinelli; Serafina Cotrone; Davide Altamura; Cinzia Giannini; Luisa Torsi; Piero Mastrorilli (pp. 15186-15189).
OFETs based on new solution-processed ester functionalized 9,10-ter-anthrylene-ethynylenes show a mobility increase of four orders of magnitude, leading to mobilities as high as 4.9 × 10−2 cm2 V−1 s−1 if the deposited film is annealed before contact deposition. The behavior is ascribed to an increase in film order at the dielectric/semiconductor interface as revealed by X-ray studies.

One-pot self-assembly of mesoporous silica nanoparticle-based pH-responsive anti-cancer nano drug delivery system by Qianjun He; Yu Gao; Lingxia Zhang; Wenbo Bu; Hangrong Chen; Yaping Li; Jianlin Shi (pp. 15190-15192).
A mesoporous silica nanoparticle (MSN)-based pH-responsive nano drug delivery system (hydrophobic drugs@micelles@MSNs) is constructed by a one-pot self-assembly strategy, exhibiting improved drug efficacy against both drug-resistant and drug-sensitive cancer cells.

Enhanced light harvesting in dye-sensitized solar cells with highly reflective TCO- and Pt-less counter electrodes by Kun Seok Lee; Jin Ho Yun; Yong-Hyeon Han; Jin-Heong Yim; Nam-Gyu Park; Kuk Young Cho; Jong Hyeok Park (pp. 15193-15196).
A systematic approach was followed to develop a new counter-electrode consisting of a highly reflective polymer substrate and a highly conductive polymer for use in dye-sensitized solar cells. The reflection of the incident light from the substrate allows more solar light to be harvested by the dye. We compared the photovoltaic performance of the TCO- and Pt-less counter-electrodes based on the reflective and pristine polymer substrates. The optimal DSSC composed of the TCO- and Pt-less counter-electrode exhibits a power conversion efficiency of 6.15% when measured using an AM1.5G solar simulator at 100 mW cm−2 light illumination.

Interface-facilitated hydrothermal synthesis of sub-micrometre graphitic carbon plates by Mingzhu Liu; Cheng Wang; Xin Wang (pp. 15197-15200).
A novel interface-facilitated synthesis of metal-free graphitic carbon plates with controllable thickness is reported. In contrast to bulk phase synthesis of the conventional hydrothermal method, the process occurs only at the interface due to the enrichment of precursors induced by the organic intermediates, allowing the use of precursors at very low concentration and alleviating the environmental burden.

Single crystal n-channel field effect transistors from solution-processed silylethynylated tetraazapentacene by Chengliang Wang; Zhixiong Liang; Yaling Liu; Xiaomu Wang; Ni Zhao; Qian Miao; Wenping Hu; Jianbin Xu (pp. 15201-15204).
Single crystals of TIPS-TAP were grown from solution using poor solvents. With gluing silver-films as source and drain electrodes, the crystals exhibited field-effect mobility up to 1.77 cm2 V−1 s−1, which is one of the highest values reported for solution-processed n-channel single crystal OFETs.

Increased photocurrent response in Nb-doped TiO2 nanotubes by Min Yang; Himendra Jha; Ning Liu; Patrik Schmuki (pp. 15205-15208).
Nb-doped TiO2 nanotube (NT) layers were grown by electrochemical anodization of Ti–Nb alloys. To successfully activate Nb doping the oxide tubes need to be annealed at sufficiently high temperatures (∼650 °C). For tubes doped with 0.1 wt% Nb not only a considerable increase in the electrical conductivity but also a significantly enhanced photocurrent (superior to any pure TiO2 nanotube layer (anatase or rutile)) was obtained.

Iodine doping in solid precursor-based CVD growth graphene film by Golap Kalita; Koichi Wakita; Makoto Takahashi; Masayoshi Umeno (pp. 15209-15213).
Doping of different elements in intrinsic graphene is of great importance to adjust the electrical and chemical properties for realization of different electronic devices. Here, we demonstrate a simple and controllable synthesis process of iodine-doped graphene film using camphor (C10H16O), a solid botanical derivative. In situ doping of iodine in a graphene film has many difficulties in a conventional chemical vapor deposition process using a gas source. In this technique, iodine was mixed with the carbon precursor and simultaneously evaporated to pyrolysis on a metal catalytic substrate. Raman and X-ray photoelectron spectroscopic studies confirm the presence of elemental iodine in the form of triiodide and pentaiodide. Simultaneously, evaporated iodine atoms remains within the few-layers graphene structure and interact with carbon atoms through a charge transfer process. This shows a straightforward technique for iodine doping in graphene and a similar approach can be adopted to deposit iodine-doped graphene on other metal substrates.

Visual detection of copper ions based on azide- and alkyne-functionalized polydiacetylene vesicles by Qingling Xu; Kyung Mi Lee; Fang Wang; Juyoung Yoon (pp. 15214-15217).
A new method for visual detection of Cu2+ based on azide- and alkyne-functionalized polydiacetylene (PDA-aa) vesicles has been developed. In the presence of ascorbic acid, Cu2+ can be reduced to Cu+ and catalyze the click reaction between the two functional groups. After incubation with Cu2+ and ascorbic acid, a PDA-aa solution changed its color from blue to red, which was attributed to conformational transition of the conjugated backbone. Other metal ions were explored but only induced negligible color changes. This method provides a naked eye detection of Cu2+ in water without the aid of complex instruments.

Nanorod decorated nanowires as highly efficient SERS-active hybrids by Ramesh Kattumenu; Chang H. Lee; Limei Tian; Michael E. McConney; Srikanth Singamaneni (pp. 15218-15223).
In order to propel surface enhanced Raman scattering (SERS)-based sensing into the real world, novel SERS-active nanostructure designs that enable facile, scalable, cost-effective, highly efficient and homogenous SERS substrates are paramount. We demonstrate the facile fabrication of highly efficient SERS-active 3D nanohybrids based on vertically aligned zinc oxide nanowires uniformly decorated with gold nanorods. The dramatic enhancement of the surface area (nearly 20 times) and hence the number of plasmonic nanostructures within the incident laser foot print results in more than three orders of magnitude increase in SERS intensity compared to planar SERS substrates. The SERS enhancement factor was found to be ∼3 × 107 with a detection limit of sub-pM for a non-resonant analyte. Apart from excellent sensitivity, the nanohybrids also exhibited excellent lateral and vertical homogeneity in SERS activity. We believe that under optimal conditions these nanohybrids can surpass the best 2D substrate designs in SERS enhancement and homogeneity.

In situ measurement of power conversion efficiency and molecular ordering during thermal annealing in P3HT:PCBM bulk heterojunction solar cells by Neil D. Treat; Chris G. Shuttle; Michael F. Toney; Craig J. Hawker; Michael L. Chabinyc (pp. 15224-15231).
Bulk heterojunction organic solar cells hold much promise as commercially viable sources of renewable energy due to their relatively inexpensive fabrication. Developing a fundamental knowledge of how processing conditions influence solar power conversion efficiency will enable rational and efficient design, optimization, and control of new organic solar cell materials. In this report, we use a combination of in situ current–voltage measurements and grazing-incidence wide-angle X-ray scattering experiments at elevated temperature to correlate the changes in photoconversion efficiency to the changes in the molecular ordering of a poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction active layer. In situ measurements of current–voltage characteristics were used to optimize the power conversion efficiency and the resulting thermal processing was in agreement with studies from repeated heating and cooling cycles. The improvements in short circuit current with thermal annealing were correlated to an increase in the population of face-on oriented crystallites of P3HT rather than improvements in molecular ordering of PCBM.

Bandgap engineered monodisperse and stable mercury telluride quantum dots and their application for near-infrared photodetection by Sungwoo Kim; Taehoon Kim; Sang Hyuk Im; Sang Il Seok; Kang Wook Kim; Sungjee Kim; Sang-Wook Kim (pp. 15232-15236).
Bandgap-engineered monodisperse HgTe NCs of different sizes were synthesized by means of a facile temperature-control method, a non-aqueous and non-Te-gas process. The photo-physical properties of the synthesized NCs in a simple photovoltaic device were tested. It was shown that this cell is capable of processing signals up to the 100 kHz level below 3 dB and hence is suitable for use in NIR photodetection.

Tunable three-dimensional ZrO2 photonic crystals replicated from single butterfly wing scales by Yu Chen; Jiajun Gu; Di Zhang; Shenmin Zhu; Huilan Su; Xiaobin Hu; Chuanliang Feng; Wang Zhang; Qinglei Liu; Andrew R. Parker (pp. 15237-15243).
Nature generates 150 000 to 200 000 Lepidoptera species (butterflies and moths). Each has more than one kind of wing scales with three dimensional complicated sub-microstructures. We hereby manipulate the original individual single wing scales (SWSs) of tropical butterfly M. didius and replicate them using ZrO2. The micro-zone reflectance spectrum and the angle dependent properties of M. didius's cover scales (with reflective index 1.56) are first studied. New optical properties (red structural colors) are observed. Then, we synthesize their ZrO2 SWS replicas (with nominal reflective index 2.12) using these SWSs as bio-templates. Results indicate that an SWS located on the M. didius wing is a highly anisotropic photonic crystal (PC) and exhibits a “prism effect”. Since one butterfly wing can supply more than 100 000 wing scales, this work presents a potential route for large-scale production of small complex photonic devices using SWS as building blocks, and can broaden present practical model pool for the PC research.

Magnetic bacterial protein Mms6 controls morphology, crystallinity and magnetism of cobalt-doped magnetite nanoparticles in vitro by Johanna M. Galloway; Atsushi Arakaki; Fukashi Masuda; Tsuyoshi Tanaka; Tadashi Matsunaga; Sarah S. Staniland (pp. 15244-15254).
Magnetic nanoparticles (MNPs) are in high demand within biomedical and nanotechnological industries. Size, shape, material and crystal quality directly affect the particle's properties, namely their magnetic characteristics, and must be tuned and controlled to meet the specification of the application. A key challenge is to refine synthetic methods to tailor the MNP properties with precision, but using cheap, high-yield, industrially robust and environmentally friendly methods. In this study we compare simple high-yield precipitation methods of producing cobalt-doped magnetite MNPs. We explore the variation of magnetic coercivity and saturation with increasing Co-doping from 0–15% in magnetite MNPs, which increases coercivity from 5–62 mT, but decreases saturation from 91–28 emu g−1. An optimum of 6% was further investigated as this produced the greatest increase in coercivity to 34 mT with a relatively small reduction in saturation magnetisation to 79 emu g−1. The methods compared are refined with the addition of the recombinant biomineralisation protein Mms6 from a magnetic bacterium, as this has been shown to help control magnetite MNP morphology and grainsize distribution in vitro. Similar control is seen here over our Co-doped magnetite synthesis. Mms6 increases the size and decreases the size distribution of room temperature co-precipitated particles from 11.7 nm to 31.7 nm. The affinity tagged protein his6Mms6 also controls the size (23.2 nm) but less effectively than Mms6. Therefore the Mms6 mediated Co-doped MNP particles are found to be single domain and thus give very clear, square magnetic hysteresis with a coercivity of 48 mT at 10 K. Hysteresis of the smaller particles (Co-doped MNP with no protein and with his-tagged protein) clearly shows both superparamagnetic and single-domain magnetic behaviours. Powder X-ray diffraction shows that both the addition of Mms6 and cobalt increases the crystal quality of the MNP. Thus Mms6 protein mediated room temperature co-precipitation offers an environmentally friendly, industrially robust route towards tailored, uniform, single-domain, high-quality Co-doped magnetite MNPs.

Structure direction in zinc oxide and related materials by cation substitution: an analogy with zeolites by Martijn A. Zwijnenburg; Stefan T. Bromley (pp. 15255-15261).
We explore the chemical and structural analogy between nanoporous aluminosilicates (zeolites) and co-substituted binary MX materials by theoretical means. Using global optimisation methods in combination with an empirical potential and density functional theory calculations we find and accurately characterise numerous low-energy co-substituted binary MX structures. Focussing on co-substituted ZnO, we demonstrate that, in line with experimental synthetic evidence, co-substitution of Zn2+ in ZnO by a combination of alkali metal cations (e.g. Li+/K+ to form |K|[LiZn3O4]) is clearly energetically favourable. We further show that, just as in the case of zeolites, co-substitution in ZnO leads to an energetic destabilisation of the dense packed structure-types found for the pure material, and, also in line with the few specific co-substituted MX syntheses reported in the literature, the stabilisation of open structure-types with large rings and cages. The global optimisation calculations further show that the specific open structure-types observed experimentally for the co-substituted materials are the likely global minima for the different substitution levels. Finally, we further consider the energetic stability against decomposition of co-substituted compounds in a combination of materials with lower and higher substitution levels and the effect of co-substitution on the optoelectronic properties of MX materials.

YSZ:Dy3+ single crystal white emitter by M. R. N. Soares; M. J. Soares; A. J. S. Fernandes; L. Rino; F. M. Costa; T. Monteiro (pp. 15262-15265).
Dysprosium doped yttria stabilized zirconia single crystals grown by the laser floating zone method crystallize in the tetragonal form as confirmed by Raman spectroscopy. In addition to the role of the dysprosium ion as stabilizer, the ion optical activation constitutes an opportunity to explore the zirconia-based material in the photonics area. The spectroscopic characteristics of the doped fibers were analyzed as a function of the amount of the Dy3+ concentration. The ratio of blue and yellow transition of the Dy3+ ions indicates that lightly doped samples should be considered for the production of the white emission. The analysis of the excitation population mechanisms provides information on the ions preferential excitation paths for the desired optical applications. It was found that under ultraviolet excitation the lightly doped fibers exhibit an intense and bright white luminescence which can be observed by naked eye at room temperature.

Salt-controlled assembly of stacked-graphene for capturing fluorescence and its application in chemical genotoxicity screening by Meng Liu; Huimin Zhao; Shuo Chen; Hongtao Yu; Xie Quan (pp. 15266-15272).
We demonstrated that the fine control over the surface charge density of chemically converted-graphene (CCG) is possible via salt “invasion”, resulting in the formation of self-assembled stacked-CCG colloids in solution, which can serve as powerful building blocks for the capturing of DNAs independent of their structure that are not available to traditional colloidal graphene-based materials, thus providing our new insight into graphene/DNA interaction. Furthermore, the self-assembled bio-composites exhibit high stability even in saline solution (0.4 M NaCl) and can function as ideal components for real-time assay for screening genotoxic chemicals, not only avoiding the complex layer-by-layer assembly in comparison with those of conventional electrochemistry-based sensors, but also improving the signal transduction. We envision that the stacked-CCG, a novel type of colloidal graphene-derived material, could open new opportunities for the rational design of multifunctional graphene-based biocomposites and provide a brand new avenue in biosensing, drug screening and genotoxicity screening in the future.

Room-temperature ferromagnetism evolution in nanostructured titanium nitride superconductors—the influence of structural defects by Chunhong Gong; Chao Yan; Jingwei Zhang; Xiaoqiang Cheng; Haoshuai Pan; Chunhui Zhang; Laigui Yu; Zhijun Zhang (pp. 15273-15278).
Titanium nitride (TiN) nanoparticles were obtained by calcining nanotubular titanic acid (NTA) in flowing ammonia. The morphology, crystal structure, and chemical features of as-prepared products were investigated by means of transmission electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, and Raman spectrometry. In the meantime, their magnetic properties were examined using a superconducting quantum interference device. Surprisingly, it was found that as-prepared TiN nanoparticles experienced a gradual diamagnetic to ferromagnetic transition at room temperature with extending nitridation time, accompanied by a noticeable shift of X-ray diffraction peaks towards lower 2θ therewith. More importantly, the magnetic properties of as-prepared TiN nanoparticles can be manipulated not only by adjusting nitridation time but also by doping non-magnetic elements during the calcining process. We speculate that the observed magnetic properties of the as-synthesized products without any magnetic impurities may be attributed to their structural defects, and there is an inner relationship between their composition and magnetic properties. As an initial study to probe the inner relationship between the composition features and magnetic properties of nanostructured dilute magnetic nitrides, this study, we believe, provides a rare example of a room-temperature magnetic transition of a superconductor and could help in acquiring insights into the origin of ferromagnetism in a broad range of non-magnetic nanostructures.

A new class of low molar mass chiral metallomesogens: synthesis and characterization by G. Shanker; C. V. Yelamaggad (pp. 15279-15287).
We report on the synthesis and evaluation of a new class of low molar mass chiral metallomesogens containing cholesterol based N-(n-alkyl)salicylideneamines coordinated in a bidentate fashion that exhibit monotropic chiral nematic (N*) and smectic A* (SmA*) phases. Copper complex with a wide range of N* phase metallomesogen was investigated for chiro-optical property by Circular Dichroism (CD) spectropolarimeter. Electrical parameters like ionisation potential (IP) and electron affinity (EA) were estimated by cyclic voltammetry (CV) experiments, which enable us to understand the redox behaviour of these metallomesogens. The energy gap (ΔE) between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) estimated by both CV and UV experiments are comparable, which implies that these complexes possess electrochemical activity.

Biofunctional self-assembled nanoparticles of folate–PEG–heparin/PBLA copolymers for targeted delivery of doxorubicin by Li Li; Kang Moo Huh; Yong-Kyu Lee; So Yeon Kim (pp. 15288-15297).
To achieve a targeted drug delivery system for chemotherapy, we synthesized a ligand-mediated nanoparticulate drug carrier composed of folate-conjugated heparin-based copolymers. The use of a heparin-based drug delivery system is of special interest due to the attractive anticancer properties of heparin. Heparin–poly(β-benzyl-l-aspartate) (HP) and folate–poly(ethylene glycol)-conjugated HP (FPHP) amphiphilic copolymers were synthesized for delivery of doxorubicin (DOX). DOX was effectively incorporated into HP and FPHP nanoparticles at a high loading content and efficiency by a simple dialysis method. The DOX-loaded HP and FPHP nanoparticles had average diameters of 86–210 nm, depending on the drug loading content and the compositions of copolymers. Both DOX-loaded HP and FPHP nanoparticles had a sustained drug release pattern, and DOX-release from nanoparticles at pH 5.0 was much faster than that at pH 7.4. This pH-dependent DOX release property may ensure intracellular drug release due to decreases in pH values inside the endosomes and lysosomes of tumor cells. Furthermore, the DOX-loaded FPHP nanoparticles exhibited a greater extent of intracellular uptake against folate-receptor positive KB cells than DOX-loaded HP nanoparticles, indicating that the FPHP nanoparticles may serve as an effective active targeting carrier. The DOX-loaded FPHP nanoparticles also showed more potent cytotoxic effect on KB cells than on folate-receptor negative A549 cells. These results suggested that the FPHP nanoparticle is a promising candidate for targeted delivery of anticancer drugs to folate-receptor positive cells.

Brightly fluorescent red organic solids bearing boron-bridged π–conjugated skeletons by Di Li; Kai Wang; Shuo Huang; Songnan Qu; Xingyuan Liu; Qingxin Zhu; Hongyu Zhang; Yue Wang (pp. 15298-15304).
Two π-conjugated organoboron complexes 1 and 2 with highly efficient red (632 nm) and deep red (670 nm) solid-state fluorescence have been constructed and qualified as potential non-doped red emitters accompanied by excellent electron-transport ability. X-ray crystal analysis demonstrated that the two side phenyl groups coordinated to each boron atom effectively keep the luminescent units apart. As a result, these red fluorophores are brightly fluorescent in the solid state (fluorescence quantum yields: 0.30 for 1 and 0.41 for 2). In addition, these boron complexes possess good thermal stability and high electron-transport ability. Organic light-emitting diodes employing 1 or 2 as non-doped emitters with simple device configuration exhibit bright red and near-infared electroluminescence.

OEI800 polyconjugates linked with ketalized glycolic acid for use as gene vectors by Xiao-hua Luo; Chen-Wei Liu; Ze-yong Li; Si-yong Qin; Jun Feng; Xian-zheng Zhang; Ren-xi Zhuo (pp. 15305-15315).
Endosomal escape of DNA polyplexes is one prominent bottleneck involved in the transfection process. Purposely against the low pH level in the endosome compartment, a series of acid-cleavable gene vectors constructed from oligoethyleneimine OEI800 polyconjugates linked with ketalized glycolic acid were designed herein and termed OEI-GKs. Their potential as gene vectors was comparatively evaluated by investigating the properties including DNA binding ability, polyplexes zeta potential, particle size, acid-triggered degradation, buffer capability before and after degradation, cytotoxicity, and transfection efficiency. The resultant data indicate that the transfection efficiency and cell-biocompatibility are dependent on the polymer architecture and molecular weights, which can be tailored by adjusting the charge ratio of OEI800 versus the linking agent. OEI-GK(1 : 1) can be potentially developed as efficient vectors for the gene delivery in terms of their transfection activity even higher than PEI25k as well as the negligible cytotoxicity. Those improved properties are believed to have association with ketal-associated degradation of OEI-GK under acid conditions in the endosome, which lead to not only easy unpacking of DNA from the hydrolyzed polyplexes but also, interestingly, substantially enhanced buffer capability.

A pH-sensitive polymeric nanovesicle based on biodegradable poly(ethylene glycol)-b-poly(2-(diisopropylamino)ethyl aspartate) as a MRI-visible drug delivery system by Qiquan Sun; Du Cheng; Xingsu Yu; Zuoquan Zhang; Jian Dai; Hao Li; Biling Liang; Xintao Shuai (pp. 15316-15326).
Diblock copolymers of poly(ethylene glycol) (PEG) and biodegradable 2-(diisopropylamino)ethanol grafted poly(l-aspartic acid) (PAsp(DIP)) were synthesized and evaluated as a MRI-visible and pH-sensitive drug delivery system. The copolymers can self-assemble into stable vesicles in aqueous solutions at neutral pH, resembling the physiological environment, whereas they disassemble in acidic endosomal/lysosomal compartments of tumor cells to achieve rapid drug release. The anticancer drug doxorubicin (DOX) and hydrophilic superparamagnetic iron oxide nanoparticles (SPIONs) were encapsulated inside the inner aqueous core of the vesicles for cancer therapy and MR imaging, respectively. In vitro drug release studies showed that the DOX release from the pH-sensitive vesicles was significantly faster at pH 5.0 than at pH 7.4. SPIONs clustering inside the inner aqueous core of the vesicles resulted in a high spin–spin (T2) relaxivity. Cell culture studies showed that the DOX-SPION-loaded vesicles could be effectively internalized by human hepatic cancer Bel 7402 cells, and DOX could be rapidly released from vesicles inside lysosomal compartments and then migrated into nuclei. Consequently effective suppression of cancer cell growth was detected. This study demonstrated the potential of the biodegradable DOX-SPION-loaded pH-sensitive vesicles as an effective multifunctional nanomedicine platform for cancer therapy due to their pH-triggerable drug release and high MRI sensitivity.

Induction of supramolecular chirality in self-assembled nanofibers triggered by environmental change by Zhegang Huang; Seong-Kyun Kang; Myongsoo Lee (pp. 15327-15331).
A carbazole end-capped rod amphiphile was synthesized and observed to self-assemble into non-chiral fibers in both methanol and water solutions even though the molecule contains a chiral oligoether dendron. Remarkably, a mixture of water and methanol induces supramolecular chirality of the nanofibers caused by a conformational change of hydrophobic aromatic rods and reduction in the hydrodynamic volume of the ethylene oxide chains. The helicity induction of the nanofibers also takes place by heating the water solution. Furthermore, the helical fibers in aqueous solution were observed to further aggregate into a rigid gel at higher temperature by enhanced hydrophobic interactions between the dehydrated oligo(ethylene oxide) dendrons.

Organic heterojunctions as a charge generation layer in tandem organic light-emitting diodes: the effect of interfacial energy level and charge carrier mobility by Yonghua Chen; Hongkun Tian; Yanhou Geng; Jiangshan Chen; Dongge Ma; Donghang Yan; Lixiang Wang (pp. 15332-15336).
A homologous series of p-type thiophene organic semiconductors NaTn (naphthyl end-capped oligothiophenes, n = 2–6 represents the number of thiophene units) were employed to form organic heterojunctions with n-type organic semiconductor C60 (C60/NaTn), applied for high-performance tandem organic light-emitting diodes (OLEDs). The effect of organic heterojunctions as a charge generation layer on the performance of tandem OLEDs has been well demonstrated. We found that not only are the highest occupied molecular orbital levels of NaTn close to the lowest unoccupied molecular orbital of C60, but also that a high charge carrier mobility is very important for constructing an effective charge generation layer to achieve high power efficiency in tandem OLEDs. Our results offer a design/selection rule for organic semiconductors used to construct effective organic heterojunction charge generation layers, which will be useful in future high-performance tandem OLEDs.

Synergistic effects of various morphologies and Al doping of spinel LiMn2O4 nanostructures on the electrochemical performance of lithium-rechargeable batteries by Won-Hee Ryu; Ji-Yong Eom; Ri-Zhu Yin; Dong-Wook Han; Won-Keun Kim; Hyuk-Sang Kwon (pp. 15337-15342).
Nanostructured electrodes have recently received great attention as components in lithium rechargeable batteries, especially because of the high power produced by the fast kinetic properties of these unique structures. Here, we report the successful synthesis of various nanostructured morphologies of spinel lithium manganese oxide electrodes (nanorod, nanothorn sphere, and sphere) from a similarly shaped manganese dioxide precursor that was controlled with different aluminium contents by the hydrothermal method. Among these structures, nanothorn sphere structured LiAl0.02Mn1.98O4 produces the highest discharge capacity of 129.8 mA h g−1, excellent rate capability (94.6 mA h g−1 at 20 C, 72% of 0.2 C-rate discharge capacity) and stable cyclic retention for 50 cycles. The excellent kinetic properties of the nanothorn sphere structure are not only due to the nanothorn sphere electrode having high surface area but also because the critical amount of Al in the nanothorn sphere electrode was located at the Mn site (16d) instead of the Li site (8a).

A new cathode for solid oxide fuel cells capable of in situ electrochemical regeneration by Wei Zhou; Zongping Shao; Fengli Liang; Zhi-Gang Chen; Zhonghua Zhu; Wanqin Jin; Nanping Xu (pp. 15343-15351).
As highly efficient energy conversion devices with the capability for power/heat co-generation and fuel flexibility, solid-oxide fuel cells (SOFCs) have received considerable attention recently as a keystone of the future energy economy. Nowadays, lack of a proper cathode with high performance at intermediate temperature (IT) has become the main obstacle in realizing this fascinating technology. Here we present (La0.8Sr0.2)0.95Ag0.05MnO3−δ as a novel CO2 tolerant cathode of IT-SOFCs, which shows silver intercalation/de-intercalation capability. Under cathodic polarization, silver can be extracted from perovskite lattice to form a 5–15 nm silver modified A-site cation deficient (La0.8Sr0.2)0.95MnO3−δ electrode with superior electrocatalytic activity and improved stability. Any performance degradation due to silver sintering can be easily in situ restored by re-intercalating silver into the perovskite lattice under anodic polarization. Through electrochemically adjusting the oxidation state and location of silver, we introduce a way for the development of high-performance silver-modified cathode for IT-SOFCs, which may contribute significantly to a sustainable future.

Preparation of nearly monodispersed Fe3O4/SiO2 composite particles from aggregates of Fe3O4 nanoparticles by Rong Fu; Xiumei Jin; Jinglun Liang; Weishi Zheng; Jiaqi Zhuang; Wensheng Yang (pp. 15352-15356).
Nearly monodispersed sphere-like Fe3O4/SiO2 composite particles were prepared via a direct silica coating using Tween-80 of modified aggregates of Fe3O4 nanoparticles obtained by the emulsion droplet solvent evaporation method. The size and magnetite proportion of the composite particles were tunable by controlling the size of the aggregates and/or the thickness of the silica coating layer.

New poly(dimethylsiloxane)/poly(perfluorooctylethyl acrylate) block copolymers: structure and order across multiple length scales in thin films by Elisa Martinelli; Giancarlo Galli; Sitaraman Krishnan; Marvin Y. Paik; Christopher K. Ober; Daniel A. Fischer (pp. 15357-15368).
Three sets of a new class of low surface tension block copolymers were synthesized consisting of a poly(dimethylsiloxane) (PDMS) block and a poly(perfluorooctylethyl acrylate) (AF8) block. The polymers were prepared using a bromo-terminated PDMS macroinitiator, to which was attached an AF8 block grown using atom transfer radical polymerization (ATRP) in such a designed way that the molecular weight and composition of the two polymer blocks were regularly varied. The interplay of both the phase separated microstructure and the mesomorphic character of the fluorinated domains with their effect on surface structure was evaluated using a suite of analytical tools. Surfaces of spin-coated and thermally annealed films were assessed using a combination of X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) studies. Both atomic force microscopy (AFM) measurements and grazing incidence small angle X-ray scattering (GISAXS) studies were carried out to evaluate the microstructure of the thin films. Even in block copolymers in which the PDMS block was the majority component, a significant presence of the lower surface energy AF8 block was detected at the film surface. Moreover, the perfluorooctyl helices of the AF8 repeat units were highly oriented at the surface in an ordered, tilted smectic structure, which was compared with those of the bulk powder samples using wide-angle X-ray powder diffraction (WAXD) studies.

Electronic and local structural changes with lithium-ion insertion in TiO2-B: X-ray absorption spectroscopy study by Toyoki Okumura; Tomokazu Fukutsuka; Asuki Yanagihara; Yuki Orikasa; Hajime Arai; Zempachi Ogumi; Yoshiharu Uchimoto (pp. 15369-15377).
X-Ray absorption fine structure (XAFS) spectroscopy was carried out on submicron sized TiO2-B, which is one of the promising candidates for negative electrode materials, in order to clarify the electronic and local structural changes during its lithium-ion insertion process. From the extended X-ray absorption fine structure (EXAFS) results of lithiated LixTiO2-B, we propose the changes in lithium-ion insertion sites during electrochemical discharging. The lithium ions are inserted into the five-fold coordinated sites and/or distorted octahedral sites distributed at the vicinity of O layers parallel to the ab plane for x

Flexible transparent conductive coatings by combining self-assembly with sintering of silver nanoparticles performed at room temperature by Michael Layani; Shlomo Magdassi (pp. 15378-15382).
Transparent conductive coatings are essential for fabrication of a variety of printed electronic devices such as flexible displays and solar cells. We report on a simple method to obtain such coatings by using aqueous dispersions of silver nanoparticles in an evaporative lithography process which is performed directly onto plastic substrates. In essence, a droplet containing silver nanoparticles is placed on top of a metallic mesh, instantaneously spreading over the mesh and the plastic substrate, and after the flow of the dispersion towards the wires of the mesh and drying, a transparent grid composed of the nanoparticles is formed. The silver nanoparticles are tailored to self-sinter upon short exposure to HCl vapors, due to the presence of polyacrylic acid salt on the surface of the particles. Therefore, immediate sintering of the silver nanoparticles in the thin lines of the grid occurs even at room temperature, enabling formation of transparent, flexible conductive grid on heat-sensitive substrates. The process yielded a conductive array having a very low sheet resistance, 9 ± 0.8 Ω/□, and a transparency above 75%. The application of the flexible conductive grid, which can replace conventional and expensive ITO, is demonstrated in an electroluminescent (EL) device.

Photo-induced self-cleaning functions on 2-anthraquinone carboxylic acid treated cotton fabrics by Ning Liu; Gang Sun; Jing Zhu (pp. 15383-15390).
Self-cleaning cotton fabrics were obtained via chemically incorporating photosensitive 2-anthraquinone carboxylic acid (2-AQC) onto the fibers through a mild and efficient esterification reaction. The 2-AQC structures on the treated cotton were confirmed by FTIR characterization. SEM images revealed that the cotton fiber surface became rougher than that of the original cotton fiber after the treatment. TGA analysis confirmed that thermal stability of the treated fibers was almost unchanged. The 2-AQC treated cotton fabrics demonstrated excellent photo-induced self-cleaning properties, including decomposition of 90% aldicarb in 3 hours of UVA exposure and inactivation of over 99% of both E. coli and S. aureus in 1 hour of the light exposure. The self-cleaning functions are a result of formation of reactive oxygen species on the light irradiated and 2-AQC treated cotton. The amount of H2O2 formed on the fabrics was determined by a titration method.

Mixed mode, ionic-electronic diode using atomic layer deposition of V2O5 and ZnO films by Parag Banerjee; Xinyi Chen; Keith Gregorczyk; Laurent Henn-Lecordier; Gary W. Rubloff (pp. 15391-15397).
We demonstrate high current rectification in a new system comprising 30 nm of hydrated vanadium pentoxide and 100 nm of zinc oxide (V2O5·nH2O–ZnO) thin film structures. The devices are prepared using a low temperature (<150 °C), all atomic layer deposition process. A key element in the rectifying properties comes from anomalous p-type conductivity in V2O5

One step method to encapsulate nanocatalysts within Fe3O4 nanoreactors by Shouhu Xuan; Yufeng Zhou; Huajian Xu; Wanquan Jiang; Ken Cham-Fai Leung; Xinglong Gong (pp. 15398-15404).
Here reported a facile approach to synthesize rattle type magnetic nanocomposite with a permeable Fe3O4 shell and noble metallic core. The core of yolk materials are controlled by varying the metallic ion precursor (such as K2PdCl4, AgNO3, KAuCl4, and Cu(NO3)2). The content of the metallic cores increases by increasing of the amount of the metallic salt. This one step method is based on an in situ reduction and Ostwald ripening process. As-obtained particles show porous nature and superparamagnetic characteristic. Moreover, the as-prepared magnetic recyclable nanocatalyst manifests high activity when evaluated for their catalytic properties and they can be separated from the reaction system by using a magnet.

An effective strategy for small molecular solution-processable iridium(iii) complexes with ambipolar characteristics: towards efficient electrophosphorescence and reduced efficiency roll-off by Jun-Xi Cai; Teng-Ling Ye; Xue-Feng Fan; Chun-Miao Han; Hui Xu; Li-Li Wang; Dong-Ge Ma; Yang Lin; Peng-Fei Yan (pp. 15405-15416).
A series of electrophosphorescent small molecular Ir3+ complexes IrPBIO2, IrPBICO, IrPBIO4 and IrPBIC2O2 for solution-processable host-free organic light-emitting diodes (OLEDs) were designed and synthesized, in which the electron-transporting 1,3,4-oxadiazole (OXD) and hole-transporting carbazole moieties were introduced through aliphatic chains to achieve balanced carrier injection/transporting. The coordinatable OXD groups were successfully and conveniently introduced through the post-substitution of Ir3+ cores. The photophysical investigation showed that compared with the single-position substituted counterparts, the double-position substitution is superior in restraining the quenching effect in solid states to endow the corresponding complexes with the much higher photoluminescence quantum yield (PLQY) in the film. The influences of peripheral carrier transporting (CT) moieties on the energy levels of frontier molecular orbitals were investigated with UPS analysis and Density Function Theory calculation. The dramatic electroluminescent (EL) performance of IrPBIC2O2 based on its host-free spin-coat phosphorescent organic light-emitting diodes (PHOLEDs), especially the remarkably restrained efficiency roll-off less than 16% at 1000 cd m−2 was realized, which demonstrated that the combined modification of the effective segregation of emitting cores by multi-position encapsulation and the balanced carrier injection/transporting through bipolar substitution is an effective strategy for realizing high-efficiency small molecular electrophosphorescent materials with the features of solution processability and strong restraining effect on quenching for host-free devices.

The structure of two new non-centrosymmetric phases of oxygen deficient bismuth manganite by A. S. Eggeman; A. Sundaresan; C. N. R. Rao; P. A. Midgley (pp. 15417-15421).
The structure of two new phases in the bismuth manganite system are reported. The phases were determined by electron diffraction studies of two oxygen-deficient bulk samples. The first phase, a minority component of bulk BiMnO2.94 forms a n = 2 Ruddlesden-Popper phase with space group Cmc21. The second phase, from bulk BiMnO2.99, is an orthorhombic structure with space group Pmn21 and a unit cell approximately equal to times the parent perovskite cell. Importantly both phases are non-centrosymmetric and offer further potential for multiferroic studies.

Indole-substituted nickel dithiolene complexes in electronic and optoelectronic devices by Simon Dalgleish; John G. Labram; Zhe Li; Jianpu Wang; Christopher R. McNeill; Thomas D. Anthopoulos; Neil C. Greenham; Neil Robertson (pp. 15422-15430).
The synthesis and full characterisation of a novel indole-substituted nickel dithiolene [Ni(mi-5edt)2] (3) is reported, and compared to its alkyl-substituted analogue [Ni(mi-5hdt)2] (4) that has been previously communicated [Dalgleish et al., Chem. Commun., 2009, 5826] [mi-5edt = 1-(N-methylindol-5-yl)-ethene-1,2-dithiolate; mi-5hdt = 1-(N-methylindol-5-yl)-hex-1-ene-1,2-dithiolate)]. Both complexes are shown to undergo oxidative electropolymerisation, yielding polymer films that retain the redox and optical properties of the monomer. The more soluble analogue 4 is shown to form high quality thin films by spin coating, which have been utilised to fabricate field-effect transistors (FETs) and bulk heterojunction photovoltaic devices (BHJ-PVs). From FET studies, the material shows ambipolar charge transport behaviour, with a maximum carrier mobility of ∼10−6 cm2 V−1 s−1 for electrons. By using 4 simultaneously as the electron acceptor as well as a NIR sensitiser in BHJ-PVs, the complex is shown to contribute to the photocurrent, extending light harvesting into the NIR region.

Hybrid gold nanoparticle-reduced graphene oxide nanosheets as active catalysts for highly efficient reduction of nitroarenes by Yuri Choi; Hee Son Bae; Eunyong Seo; Seonwan Jang; Kang Hyun Park; Byeong-Su Kim (pp. 15431-15436).
We demonstrate a simple, one-step synthesis of hybrid gold nanoparticle–graphene oxide nanosheets (Au–GO) through electrostatic self-assembly. This method affords a facile means of controlling the effective concentration of the active Au nanoparticles on the graphene sheets, but also offers the necessary stability of the resulting Au–GO nanostructure for catalytic transformation. Furthermore, this hybrid Au–GO is successfully employed in the catalytic reduction of a series of nitroarenes with high catalytic activity. Through careful investigation of the catalyst, we find the synergistic catalytic effect of Au nanoparticles and GO, further highlighting the significance of hybrid Au–GO nanostructure. Considering the wide potential applications of a two-dimensional graphene sheet as a host material for a variety of nanoparticles, the approach developed here may lead to new possibilities for the fabrication of hybrid nanoparticle–graphene nanosheet structures endowed with multiple functionalities.

Efficient surface structuring and photoalignment of supramolecular polymer–azobenzene complexes through rational chromophore design by Jaana Vapaavuori; Ville Valtavirta; Tapani Alasaarela; Jun-Ichi Mamiya; Arri Priimagi; Atsushi Shishido; Matti Kaivola (pp. 15437-15441).
Rational selection of the para-substituent of azobenzene chromophores in supramolecular polymeric complexes is exploited to control the chromophore–chromophore intermolecular interactions occurring in the material system. This allows optimizing the material system for either efficient surface-relief formation or for high and stable photoalignment. The surface-relief gratings can be subsequently coated with amorphous TiO2 using atomic layer deposition, resulting in high-quality and high-index organic–inorganic gratings with vastly improved thermal stability compared to all-polymeric gratings.

Hydrothermal synthesis and automotive exhaust catalytic performance of CeO2 nanotube arrays by Ying-jie Feng; Li-li Liu; Xi-dong Wang (pp. 15442-15448).
Ceria (CeO2) nanotube arrays with precisely defined size and density were directly synthesized on glass and cordierite substrates using a ZnO nanorods-assisted hydrothermal method. Eliminating the procedures of template removal and film coating, the one-step synthesis approach could greatly broaden the applications for materials with tubular structures. The proper concentration of cerium nitrate precursor solution acts a vital role to adjust the instantaneous precipitation of CeO2 and dissolution of ZnO templates. The as-prepared CeO2 tube arrays were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD) techniques, which reveal a regular tubular structure with the average diameter of 500 nm and length of 3 μm. The automotive exhaust catalytic performance of CeO2 tube arrays prepared on the cordierite was evaluated. Compared with the ceria nanoparticles film, the target CeO2 tubes exhibit improved catalytic activities at a low start-up temperature for oxycarbide and hydrocarbon. Furthermore, the palladium-decorated CeO2 tubes exhibit a higher catalytic activity for the degradation of oxynitride than that of palladium/ceria particles/cordierite.

A green and ultrafast approach to the synthesis of scalable graphene nanosheets with Zn powder for electrochemical energy storage by Yanzhen Liu; Yongfeng Li; Ming Zhong; Yonggang Yang; Yuefang Wen; Maozhang Wang (pp. 15449-15455).
We developed a novel and ultrafast method to reduce graphene oxide (GO) with Zn powder in mild alkaline conditions under ultrasonication only for 10 min at room temperature. The as-prepared graphene nanosheets (GNs) are characterized by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and so on. Moreover, we proposed the reducing mechanism under which Zn powder and GO formed numerous Zn-GO primary batteries in the presence of ammonia solution, which can effectively remove a significant fraction of the oxygen-containing functional groups and yield a C/O ratio as high as 8.09 and 8.58 reduced by ultrasonication for 10 min and 60 min, respectively. A maximum specific capacitance of 116 F g−1 in an aqueous KOH electrolyte solution has been obtained. This approach presents us with a possibility for an environmentally friendly, ultrafast, low-cost and large-scale production of GNs and great potentials in electrochemical energy storage applications of graphene-based materials.

A possible anticancer drug delivery system based on carbon nanotube–dendrimer hybrid nanomaterials by Ebrahim Mehdipoor; Mohsen Adeli; Masoumeh Bavadi; Pezhman Sasanpour; Bizhan Rashidian (pp. 15456-15463).
Iron oxide nanoparticles, γ-Fe2O3NP, were deposited onto the surface of multi-walled carbon nanotubes and CNT/γ-Fe2O3NP hybrid nanomaterials were obtained. Then linear-dendritic ABA type block copolymers consisting of polyethylene glycol as B block and poly(citric acid) as A block, PCA–PEG–PCA, were synthesized and cisplatin (cis-diamminedichloroplatinum (CDDP)—a platinum-based chemotherapy drug) was conjugated with their carboxyl functional groups and CDDP/PCA–PEG–PCA anticancer prodrugs were prepared. Noncovalent interactions between CDDP/PCA–PEG–PCA anticancer prodrugs and CNT/γ-Fe2O3NP hybrid nanomaterials led to CDDP/PCA–PEG–PCA/CNT/γ-Fe2O3NP drug delivery systems. There are several key features of these hybrid drug delivery systems: (i) their ability to cross cell membranes and also high surface area per unit weight for high drug loading assigned to CNTs, (ii) high functionality, water solubility and biocompatibility assigned to PCA–PEG–PCA linear-dendritic copolymers and (iii) targeting tumors using a magnetic field assigned to γ-Fe2O3 nanoparticles. The efficacy of drug delivery systems for killing the cancer cells and targeting the drugs towards tumors was investigated.

Nanostructured LDH-container layer with active protection functionality by J. Tedim; M. L. Zheludkevich; A. N. Salak; A. Lisenkov; M. G. S. Ferreira (pp. 15464-15470).
Self-healing protective coatings based on different types of nanocontainers of corrosion inhibitors have been recently developed and reported as promising solutions for many industrial applications. Layered double hydroxide (LDH) nanocontainers are among the most interesting systems since they confer the delivery of inhibitors on demand under action of corrosion-relevant triggers such as the presence of corrosive anions or local change of pH. In this paper, we report for the first time a new approach based on formation of a nanostructured LDH-container layer directly on the metal surface as a result of conversion reaction with a metal (aluminium alloy 2024) surface. The methodology allows the formation of a spatially differentiated LDH structure preferentially on surface sites located at active intermetallics. The LDH container layer loaded with vanadate ions provides an efficient active corrosion protection and can be used as a functional layer in self-healing coating systems.

Solid-state dye-sensitized solar cell with a charge transfer layer comprising two ionic liquids and a carbon material by Chuan-Pei Lee; Min-Hsin Yeh; R. Vittal; Kuo-Chuan Ho (pp. 15471-15478).
A solid-state composite electrolyte, comprising two ionic liquids and a carbon material, was sandwiched between a dye-sensitized porous TiO2 working electrode and its counter electrode to fabricate a solid-state dye-sensitized solar cell (DSSC); the ionic liquids were 1-ethyl-3-methylimidazolium iodide (EMII, ionic liquid crystal) and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4, room temperature ionic liquid), and the carbon materials were carbon black (CB), multi-wall carbon nanotubes (MWCNT), and single-wall carbon nanotubes (SWCNT). A cell efficiency (η) of 0.41% was achieved by using the bare 1-ethyl-3-methylimidazolium iodide (EMII) as the charge transfer intermediate (CTI); an efficiency of 2.52% was achieved for a solid-state DSSC by the incorporation of carbon black (CB) in the same composite electrolyte. To further improve the cell efficiency, we utilized 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4), a crystal growth inhibitor, as an additive to the electrolyte. The binary CTI (EMII plus EMIBF4) was in the form of a solid, until the weight percentage of EMIBF4 in the binary CTI exceeded the level of 60%. A cell efficiency of 3.09% was obtained using an electrolyte containing the CB and the binary CTI; the binary CTI for this cell contained EMII and EMIBF4 in the ratio of 8/2. When the CB was replaced with MWCNT and SWCNT, the cell efficiency could be improved to 3.53% and 4.01%, respectively. Long-term durability of the DSSC with SWCNT–binary CTI was found to be far superior to that of the cell with an organic solvent electrolyte, and in fact the durability was uninterrupted for at least 1000 h. Scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), differential scanning calorimetry (DSC), and laser-induced photo-voltage transients were used to substantiate the results.

Activation and local structural stability during the thermal decomposition of Mg/Al-hydrotalcite by total neutron scattering by Maurice C. D. Mourad; Mohamed Mokhtar; Matthew G. Tucker; Emma R. Barney; Ronald I. Smith; Abdulrahaman O. Alyoubi; Sulaiman N. Basahel; Milo S. P. Shaffer; Neal T. Skipper (pp. 15479-15485).
The activation of synthetic hydrotalcite, the carbonated layered double hydroxide (LDH) with ratio Mg2+/Al3+ = 3 and structural formula [Mg6Al2(OH)16]2+·CO32−n(H2O), has been investigated using neutron and X-ray diffraction. In situ neutron diffraction was used to follow the structural phase transformations during the thermal decomposition (calcination) of hydrotalcite under vacuum in the temperature range 298–723 K, and during which the residual gas evolved by the sample was analysed by mass spectrometry. Detailed structural information of the LDH and mixed metal oxides (MMOs) was extracted from both the Bragg peaks and the total scattering. These two analysis techniques provide complementary insight into the relevant transition mechanisms, since Bragg diffraction originates from long-range periodicities within the samples while total scattering reveals the subtleties of the local atomic environment. This latter information is particularly important for our understanding of catalytic activity since it elucidates the local metal coordination. We find that, during the calcination process, the local environment around the metal centres is robust, as the various stages during the phase transition have identical local structures. The implications of these new results for the nature of the MMOs is discussed in relation to the well-studied, reverse, rehydration reaction, and the high propensity of trivalent Al ions to migrate to tetrahedrally-coordinated lattice sites.

Preparation and characterization of MRI-active gadolinium nanocomposite particles for neutron capture therapy by Heui Kyoung Cho; Hyun-Jong Cho; Saifullah Lone; Dae-Duk Kim; Jeong Hyun Yeum; In Woo Cheong (pp. 15486-15493).
We demonstrate the synthesis and characteristics of MRI-active Gd2O3 core/SiO2 shell/poly(2-methacryloyloxyethyl phosphorylcholine) corona composite nanoparticles (Gd2O3@SiO2@PMPC NPs). The prepared NPs have a number of attractive features in cancer diagnosis and neutron capture therapy (NCT): biocompatibility, colloidal stability, low cytotoxicity, nucleus affinity, passive targeting, etc. Monodisperse and highly crystalline Gd2O3 NPs were prepared using a polyol protocol to control the average particle size and surface properties. The Gd2O3 NPs were then functionalized with SiO2 and a biomimetic layer of PMPC, to achieve reduced toxicity and enhanced nucleus affinity, for use as an MRI-active Gd-NCT agent. The size of the NPs was tailored to be from 50 to 100 nm for passive accumulation in tumor tissue through loosened capillary vessels. The morphologies and structures of Gd2O3, Gd2O3@SiO2–Br, and Gd2O3@SiO2@PMPC NPs were studied by FT-IR, XRD, HR-TEM, and TGA. In vitro cytotoxicity was investigated with three kinds of normal and cancer cells, and in vitro and in vivo MRI analyses were performed to confirm the contrast ability, accumulation, and sustentation of NPs in tumor tissues.

Homoleptic tris-cyclometalated iridium complexes with 2-phenylbenzothiazole ligands for highly efficient orange OLEDs by Renjie Wang; Di Liu; Huicai Ren; Ting Zhang; Xinzeng Wang; Jiuyan Li (pp. 15494-15500).
Homoleptic tris-cyclometalated iridium(iii) complexes containing 2-phenylbenzothiazole derivatives as ligands have been successfully synthesized and characterized for the first time. Electron-donating (CH3, OCH3) and -withdrawing groups (F) were introduced into the 6-position of the benzothiazole moiety in the ligands to verify their influence on the optical and electronic properties of the complexes. Organic light-emitting diodes using these iridium complexes as doped emitters exhibited orange electrophosphorescence with excellent performances. An extremely high brightness of 95 800 cd m−2 and a maximum luminance efficiency of 87.9 cd A−1 (46.0 lm W−1) were achieved for the pristine complex without any substituent in the ligand. These performances represent a significant improvement for vacuum-deposited orange OLEDs and the new record of the efficiencies for orange OLEDs reported so far. The substituents in the ligand were observed to be rather unimportant to influence the performance of this series of iridium complexes.

Cyclometallated platinum(ii) complexes of 1,3-di(2-pyridyl)benzenes: tuning excimer emission from red to near-infrared for NIR-OLEDs by Ester Rossi; Lisa Murphy; Phillipa L. Brothwood; Alessia Colombo; Claudia Dragonetti; Dominique Roberto; Renato Ugo; Massimo Cocchi; J. A. Gareth Williams (pp. 15501-15510).
The Pt(ii) complex N^C2^N-1,3-di(2-pyridyl)benzene platinum chloride (PtL1Cl) is known to display efficient triplet luminescence in the green region of the spectrum, and to form an unusually emissive excimer that emits around 690 nm. In this contribution, the introduction of trifluoromethyl groups into either the 4- or 5-position of the pyridyl rings of the ligand is shown to lead to a red-shift in the excimer band, moving it into the near infra-red (NIR) region. The new ligands, synthesised by either Suzuki or Stille cross-coupling methods, are 1,3-bis(4-(trifluoromethyl)pyridin-2-yl)benzene HL27, 1,3-bis(4-(trifluoromethyl)pyridin-2-yl)-4,6-difluorobenzene HL28, and 1,3-bis(5-(trifluoromethyl)pyridin-2-yl)-4,6-difluorobenzene HL29, from which the corresponding Pt(ii) complexes PtLnCl have been prepared. The monomer and excimer emission energies in solution are compared with those of PtL1Cl and PtL22Cl {HL22 = 1,3-di(2-pyridyl)-4,6-difluorobenzene}. The order for the monomer can be rationalised in terms of the stabilising effects of the F atoms and the CF3 groups on the HOMO and LUMO respectively. The order of excimer emission proves to be subtly different, but the most red-shifted complex in both cases is PtL27Cl. The electroluminescence of neat films of the complexes as emitting layers in OLEDs displays uniquely excimer-like emission, extending well into the technologically important NIR region.

Red-ox behaviour in the La0.6Sr0.4CoO3±δ-CeO2 system by Elena Yu. Konysheva; Stephen M. Francis; John T. S. Irvine; Aurélie Rolle; Rose-Noelle Vannier (pp. 15511-15520).
The compositions in the (100 −

Porous manganese oxide generated from lithiation/delithiation with improved electrochemical oxidation for supercapacitors by Hui Xia; Ying Shirley Meng; Xiaogan Li; Guoliang Yuan; Chong Cui (pp. 15521-15526).
For manganese oxides with low manganese oxidation states, such as MnO or Mn3O4, the electrochemical oxidation during potential cycling is critical to achieve high supercapacitor performance. In this work, dense Mn3O4 thin films are prepared by pulsed laser deposition. An electrochemical lithiation/delithiation process is applied to the Mn3O4 thin film, which leads to a nanoporous structure of the film and greatly increases the porosity of the film. The nanoporous MnOx thin film electrode exhibits significantly improved supercapacitive performance compared to the as-prepared Mn3O4 thin film electrode. After 1000 cyclic voltammetric scans in 1 M Na2SO4 electrolyte between 0 and 1 V, only part of the surface of the as-prepared Mn3O4 thin film transforms into a MnO2 porous structure while the complete film of the nanoporous MnOx transforms into a MnO2 porous structure. It is believed that the nanoporous structure, which facilitates the electrolyte penetration, leads to the completion of electrochemical oxidation through the film during the potential cycling, resulting in promising supercapacitive performance of the film.

Formation of relief structures on fibres by photo-embossing by Mian Dai; Olivier Thomas Picot; Nanayaa Freda Hughes-Brittain; Ton Peijs; Cees W. M. Bastiaansen (pp. 15527-15531).
Relief structures are created on the surface of fibres to generate new effects in these fibres. More specifically, photo-embossing is used to generate the relief structures and to generate a non-contact process without etching procedures which could eventually be applied in high-speed and continuous spinning lines. Typically, a photopolymer mixture consisting of a polymeric binder, a monomer and a photo-initiator is directly spun into a monofilament fibre. The rheological properties of the photopolymer mixture are measured, and it is shown that the photopolymer mixture is visco-elastic at elevated temperatures. Fibres are prepared from the photopolymer mixture, and surface relief structures are generated perpendicular to the fibre axis by photo-embossing using a mask exposure. Optical microscopy (OM) and scanning electron microscopy (SEM) are employed to study the surface morphology of the fibres. It is shown that the height of the surface relief structures is strongly dependent on the pitch of the line mask and on the diameter of the fibres. At optimized conditions, patterned fibres are produced with well-defined surface relief structures. The fibres are rather brittle which is related to the crosslinked chemical network in the fibres.

Aldehyde detection by ZnO tetrapod-based gas sensors by Davide Calestani; Roberto Mosca; Massimiliano Zanichelli; Marco Villani; Andrea Zappettini (pp. 15532-15536).
Zinc oxide (ZnO) tetrapods have been synthesized and prototypal gas sensors for volatile organic compounds (VOCs) have been realized with this sensing nanomaterial. Sensor characterization has been focused on aldehydes, such as acetaldehyde (or ethanal) and propionaldehyde (or propanal), whose detection at ppb levels is extremely important for monitoring environmental, domestic and food pollution, as well as for some sickness diagnosis and other medical applications. The response of gas sensor prototypes has been measured as a function of concentration, temperature, relative humidity and time. Good response values at ppb levels and some peculiar behaviours have been pointed out.

Synthesis of mesoporous composite materials of nitrogen-doped carbon and silica using a reactive surfactant approach by Jens Peter Paraknowitsch; Yuanjian Zhang; Arne Thomas (pp. 15537-15543).
Mesoporous composite materials of nitrogen-doped carbon and silica were synthesised in a one-step-process applying a soft templating procedure. The template used in the sol–gel synthesis of the silica is a cationic surfactant with distinct reactivity to form nitrogen-doped graphitic carbon upon heating. This reactivity is derived from the combination of the dicyanamide anion with a nitrogen-containing pyridinium cation, as it is known from ionic liquids used as nitrogen-doped carbon precursors. Thus applying this surfactant in a conventional sol–gel synthesis yields a silica gel doped with a precursor for N-doped carbon. By subsequent annealing mesoporous composite materials of silica and nitrogen-doped carbon are obtained.

A facile building-block synthesis of multifunctional lanthanide MOFs by Stefania Tanase; Marjo C. Mittelmeijer-Hazeleger; Gadi Rothenberg; Corine Mathonière; Véronique Jubera; Jan M. M. Smits; René de Gelder (pp. 15544-15551).
We report a building blocks approach providing a direct route to multifunctional MOFs, that display photoluminescent properties, robustness, porosity and in some cases unique magnetic properties. The self-assembly of [Mo(CN)8]4− with several in situ prepared lanthanide building blocks gives 3D robust porous networks with open channels. This approach solves the coordination problem, allowing exact placement of the lanthanide ions within the structure. Our MOFs feature good thermal stability and permanent porosity thanks to the strong carboxylate and cyanide linkages. The fact that we have both nitrogen-containing ligand and a π-system means that these MOFs can be excited using low-energy photons. Efficient visible emission was observed for MOFs containing Eu(iii) and Tb(iii). Surprisingly, the Tb-MOF shows ferromagnetic behavior, proving that the magnetic interaction between Tb(iii) ions is strong enough to compensate the ligand field effects.

A facile way to fabricate highly efficient photoelectrodes with chemical sintered scattering layers for dye-sensitized solar cells by Zhang Lan; Jihuai Wu; Jianming Lin; Miaoliang Huang (pp. 15552-15557).
A bifunctional nanocrystal TiO2 structure able to offer both light scattering and electron generating properties was prepared by a simple method of adding a basic NH3·H2O agent to an acidic nanocrystal TiO2 paste to form bigger TiO2 nanocrystal aggregates. When used to prepare the second nanocrystal TiO2 layer in the photoelectrode, the photovoltaic performance of DSSCs were obviously enhanced, and the highest energy conversion efficiency attainable was 8.11%, which is much higher than that of a DSSC containing a single nanocrystal TiO2 layer prepared using the original acidic TiO2 paste (4.34%).

A theoretical discussion on the relationships among molecular packings, intermolecular interactions, and electron transport properties for naphthalene tetracarboxylic diimide derivatives by Yun Geng; Shui-Xing Wu; Hai-Bin Li; Xiao-Dan Tang; Yong Wu; Zhong-Min Su; Yi Liao (pp. 15558-15566).
Three naphthalene tetracarboxylic diimide derivatives 1–3 with high electron mobilities and long-term ambient stabilities were investigated employing Marcus–Levich–Jortner formalism at the density functional theory (DFT) level. The complicated relationships among molecular packings, intermolecular interactions, and transport properties for these compounds were focused on and analyzed through investigating the sensitivities of transfer integrals to intermolecular relative orientations, the optimizations of the major transport pathways and the calculations of intermolecular interaction energies by using dispersion-corrected DFT. The results show that the transfer integrals are sensitive to the subtle changes of relative orientations of molecules, especially for core-chlorinated compounds, and there is an interplay between intermolecular interaction and molecular packing. It is found that the transfer integrals associated with the molecular packing motifs of these systems determine their electron mobilities. Interestingly, further discussions on band structures, the anisotropies and temperature dependences of mobilities, and the comparisons of mobilities before and after optimization indicate that the intermolecular packing motifs in the film state may be different from those in the crystalline state for 2. Finally, we hope that our conjecture would facilitate the future design and preparation of high-performance charge-transport materials.

High performance adsorbents based on hierarchically porous silica for purifying multicomponent wastewater by Wenping Shi; Shengyang Tao; Yongxian Yu; Yuchao Wang; Wei Ma (pp. 15567-15574).
Hybrid hierarchically porous silica adsorbents were simply fabricated by the sol–gel method and modified with thiol or sulfonic groups. These materials with pores on both micrometre and nanometre scales exhibit a satisfactorily adsorptive property to various pollutants in water, including heavy metal ions (Hg2+, Cd2+, Pb2+, Cu2+, Ag+ and CrO42−) and organic compounds (dyes, biogenic amines, pesticides and amino acids). The thiol functionalized hierarchically porous silica micro-foam (SH-HSM), which has a low thiol content (0.66 mmol g−1), shows significantly high adsorption capability to Hg2+ (140.1 mg g−1) in particular. Then sulfonic acid-functionalized adsorbent (SO3H-HSM) was obtained through direct oxidization of SH-HSM by H2O2 without destruction of the hierarchical structure. It was found that SO3H-HSM could effectively remove organic compounds with positive charge in solution through electrostatic interactions. The adsorption capability of SO3H-HSM for some basic dyes, such as fuchsin basic, could reach approximately 1145.2 mg g−1. The mixture of SH-HSM and SO3H-HSM showed good purifying capacity to simulate multicomponent wastewater, containing different inorganic and organic chemicals. The removal rate for any of the pollutants was more than 90%, and could even reach 100% for metal ions and dyes. The strong adsorption ability of these porous adsorbents may be due to the interwoven meso- and macroporous structures which can increase mass transport and easier accessibility for pollutants to the active sites.

Non-volatile transistor memory fabricated using DNA and eliminating influence of mobile ions on electric properties by Tomoyoshi Yukimoto; Sei Uemura; Toshihide Kamata; Kazuki Nakamura; Norihisa Kobayashi (pp. 15575-15579).
An organic thin-film transistor (OTFT) memory was fabricated using deoxyribonucleic acid (DNA) as a gate dielectric layer. Since natural DNA contains intrinsic ions and water molecules, the OTFT exhibited low resistivity and a low on/off ratio because of the mobile ions. In order to remove these mobile ions from DNA, it was complexed with a bulky surfactant through an electrostatic interaction. The OTFT fabricated using a DNA–surfactant complex exhibited a relatively high on/off ratio because of the decrease in the off-current. Residual ions that remained in the complex caused a decrease in the cell performance with respect to parameters such as the on/off ratio and long-term memory stability. When poly(methyl methacrylate) (PMMA) was layered on the DNA–surfactant layer, the OTFT exhibited better on-current and long-term memory stability than a typical OTFT. The pentacene layer deposited on the PMMA surface as a semiconductor had a relatively large grain size and relatively high crystallinity. This contributed to an increase in the hole mobility in the pentacene layer and the prevention of the abovementioned adverse effects of the residual ions. Consequently, the performance of the OTFT memory having the DNA complex was considerably improved.

A polymer brush organic interlayer improves the overlying pentacene nanostructure and organic field-effect transistor performance by Song Hee Park; Hwa Sung Lee; Jong-Dae Kim; Dag W. Breiby; Eunhye Kim; Yeong Don Park; Du Yeol Ryu; Dong Ryeol Lee; Jeong Ho Cho (pp. 15580-15586).
We investigated the crystalline nanostructures and film morphologies of pentacene films deposited onto a polymer brush organic interlayer in high performance organic field-effect transistors (OFETs). Polymer brushes were grafted onto the oxide substrates by spin-coating and thermal annealing. Pentacene FETs fabricated on top of the polymer brushes showed excellent device performance, with a field-effect mobility of 0.82 cm2 V−1 s−1 and an on/off current ratio of 107. These properties were superior to those of devices using typical surface modification techniques, such as octadecyltrichlorosilane (ODTS) and hexamethyldisilazane (HMDS). The improvements in OFET performance appeared to be due to the pentacene layer's crystalline nanostructure and grain interconnectivity, which formed during the submonolayer stage of film growth. This stage of growth is strongly correlated with the surface energy, morphology, and viscoelastic properties of the resulting gate dielectrics. The inclusion of a polymer brush dielectric surface modification is a significant step toward optimizing the nanostructures of organic semiconductors, which are directly linked to device performance enhancement, by engineering the interfaces in OFETs.

Enhanced performance and stability of inverted organic solar cells by using novel zinc-benzothiazole complexes as anode buffer layers by Somnath Dey; Paola Vivo; Alexander Efimov; Helge Lemmetyinen (pp. 15587-15592).
Performance of inverted bulk-heterojunction solar cells with widely used tris(8-quinolinolate)aluminium(iii) (Alq3) is compared with a series of novel zinc-benzothiazole (Znb2) derivatives as buffer layer. The devices including a Znb2 thin layer between the poly(3-hexylthiophene) (P3HT):C61-butyric acid methyl ester (PCBM) blend and the Au anode show a significant improvement in the power conversion efficiency (η), which is enhanced by 30% compared to Alq3 cells. Moreover, by combining both Alq3 and Znb2 in the device as a double buffer layer prior to the metal electrode deposition, the efficiency improves by 40%. The reasons for the enhanced performance of Znb2 cells are attributed to the efficient charge transport and electron/exciton blocking properties. Furthermore it is expected that the deposition of Znb2 modifies the Au work function to facilitate the hole transport and collection at the anode, and encapsulate the P3HT/PCBM blend during the electrode deposition. The presented photovoltaic cells also show high stability in ambient air conditions over a period of 245 days, which evidences the need of Znb2 buffer layers for long-term device durability.

Hybrid graphene–metal nanoparticle systems: electronic properties and gas interaction by Verawati Tjoa; Wei Jun; Vinayak Dravid; Subodh Mhaisalkar; Nripan Mathews (pp. 15593-15599).
Electrical properties of reduced graphene oxide (rGO) decorated with gold and silver nanoparticles were studied. Metal nanoparticles p-dope rGO through charge transfer which causes a potential drop at the metal nanoparticle–graphene interface. Probing by reactive gases showed that the nanoparticles provide interaction sites, inducing the sensitivity to H2S and improving the sensitivity to NO2.

Novel lanthanide luminescent materials based on multifunctional complexes of 2-sulfanylpyridine-3-carboxylic acid and silica/titania hosts by Lei Guo; Lianshe Fu; Rute A. S. Ferreira; Luis D. Carlos; Qiuping Li; Bing Yan (pp. 15600-15607).
Three different types of organic–inorganic hybrid materials formed by trivalent lanthanide (Ln3+ = Eu3+, Tb3+) complexes covalently grafted to silica-, titania-, or silica/titania-based hosts have been prepared and fully characterized. Since the organic ligand 2-sulfanylpyridine-3-carboxylic acid (SPC), a derivative of nicotinic acid, exhibits three potential binding sites (pyridine N, sulfhydryl S and carboxylic O), the multifunctional precursor can be prepared through the reaction of the carboxylic group with titanium alkoxide and the modification of the sulfhydryl group with silane crosslinking reagents. Thus, the organic–inorganic hybrid materials covalently grafted with Eu3+ or Tb3+ complexes are synthesized through coordination of the Ln3+ ions with the heterocyclic group in the multifunctional precursor during the sol–gel process. The obtained hybrid materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL). The detailed PL studies showed that, compared with the titania-based hybrid materials (denoted as Ln–SPC–Ti), the silica- and silica/titania-based hybrid materials (denoted as Ln–SPCSi and Ln–SPCSi–Ti, respectively) exhibited higher luminescence intensity and emission quantum efficiency.

Ag shell morphology on Au nanorod core: role of Ag precursor complex by Kyoungweon Park; Lawrence F. Drummy; Richard A. Vaia (pp. 15608-15618).
Multicomponent nanostructures have substantial potential in a wide range of applications due to their unique chemical, optical, and magnetic properties, which arise from their architecture, composition, and associated heterojunctions. Colloidal approaches provide synthetic routes to fabricate these multicomponent metal nanostructures; however the complexity of processing parameters many times limits reproducibility and minimization of undesired secondary structures. By comparing the architecture across a diverse set of processing parameters for Ag shell growth on Au nanorods (NRs), we demonstrate that the composition and size of the in situ formed Ag precursor complex are the most critical contribution to the growth mechanism. Systematic control of these characteristics by varying hexadecyltrimethylammonium bromide (CTAB) concentration and aging time of the precursor-template solution, as well as pH and temperature of the final reaction solution, enables reproducible and continuous variation of the Ag shell architecture from conformal to rectilinear, and provides a unifying view of prior literature reports.

Effect of chemical composition of SBA-15 on the adsorption and catalytic activity of α-chymotrypsin by Francesco Secundo; Gabriella Roda; Michela Vittorini; Adrian Ungureanu; Brindusa Dragoi; Emil Dumitriu (pp. 15619-15628).
The adsorption of α-chymotrypsin (α-CT) on Al-containing mesoporous materials based on SBA-15 topology was investigated. The insertion of various amounts of aluminium was achieved using the two-step (pH-adjusting) method and the physico-chemical properties of these materials were characterized by small angle X-ray diffraction, nitrogen adsorption/desorption isotherm curves and 27Al MAS NMR spectroscopy, ammonia adsorption microcalorimetry and chemical analyses. The amount of adsorbed enzyme was found to be dependent on the Si/Al ratio of solid surfaces, pH of adsorption and, in the case of Al-containing material, on the ionic strength. Various mechanisms of adsorption are discussed. The activity of immobilized α-CT was examined using the transesterification of N-acetyl-l-phenylalanine ethyl ester with 1-propanol as test-reaction. The catalytic efficiency is strongly dependent on the nature of the support. In order to reduce the leaching of enzyme from the support surface and improve its reusability, cross-linking of the adsorbed enzyme was carried out by glutardialdehyde. In general, these mesoporous silica materials are attractive candidates for enzyme immobilization and biomedical applications due to their high surface area, tunable surface properties and pore size, large pore volume and biocompatibility.

Polymer based silver nanocomposites as versatile solid film and aqueous emulsion SERS substrates by Sara Fateixa; Ana Violeta Girão; Helena I. S. Nogueira; Tito Trindade (pp. 15629-15636).
Nanocomposites containing Ag nanoparticles (average diameter ∼11 nm) dispersed in poly(tert-butylacrylate) were prepared by in situ polymerization via miniemulsions and constitute active and versatile SERS substrates. The use of this synthetic strategy enables the dual use of the final composites as SERS substrates, both as aqueous emulsions and as cast films, shown here by several measurements using thiosalicylic acid as the testing analyte. The main advantage of these types of materials is related to the potential to scale up and the widespread use of handy substrates, using technology already available. This requires homogeneous composite substrates with SERS activity and this was demonstrated here by means of confocal Raman microscopy. Finally, a series of experiments were carried out on Ag/polymer nanocomposites submitted to temperature variations below and above the polymer glass transition temperature (Tg) in order to conclude about the effect of temperature processing conditions on the composites' SERS activity.

Organic thin-film transistors with a photo-patternable semiconducting polymer blend by Longzhen Qiu; Qiong Xu; Wi Hyoung Lee; Xiaohong Wang; Boseok Kang; Guoqiang Lv; Kilwon Cho (pp. 15637-15642).
A blend of organic semiconductors and photocrosslinkable insulating polymers was photolithographically patterned to yield organic thin-film transistors (OTFTs). The semiconducting polymer of the blend, poly(3-hexylthiophene), was present as a nanofibrillar network and yielded excellent electronic properties. The insulating polymer matrix, poly(vinyl cinnamate), provided the photosensitivity required for photopatterning. The photopatterned TFT devices showed large on/off ratios (>105) and high mobilities (0.015 cm2 V−1 s−1) comparable to those of devices patterned by conventional means using the same semiconducting materials. This simple method permitted the high-resolution cost-effective patterning of organic semiconductors and may play an important role in the mass-production of organic electronic devices.

Nonvolatile memory devices based on polyimides bearing noncoplanar twisted biphenyl units containing carbazole and triphenylamine side-chain groups by Yue-Qin Li; Run-Chen Fang; An-Min Zheng; Yue-Ying Chu; Xian Tao; Hui-Hua Xu; Shi-Jin Ding; Ying-Zhong Shen (pp. 15643-15654).
Two novel polyimides, PI(CzBD-BTFBPDA) and PI(TPABD-BTFBPDA), consisting of alternating electron-donating 2,2′-bis[4-(9H-carbazol-9-yl)phenyl]- or 2,2′-bis[4-(diphenylamino)phenyl]-substituted biphenyl moieties and electron-accepting phthalimide moieties were synthesized and characterized. These polyimides are thermally stable with 5% weight loss over 500 °C and the glass transition temperatures of the polyimides were found to be 293 °C. The optical band gaps of PI(CzBD-BTFBPDA) and PI(TPABD-BTFBPDA) were 3.42 and 3.30 eV, respectively, indicating the significance of the linkage groups. The estimated energy levels (HOMO, LUMO) of PI(CzBD-BTFBPDA) and PI(TPABD-BTFBPDA) were (−5.51, −2.10) and (−5.22, −2.02) eV, respectively. Resistive switching devices with the configuration of Al/polymer/ITO were constructed from these polyimides by using the conventional solution coating process. The as-fabricated PI(CzBD-BTFBPDA) film exhibited a nonvolatile bipolar write-once–read-many times (WORM) memory character, whereas devices with the PI(TPABD-BTFBPDA) film showed “write–read–erase” flash type memory capability. The ON/OFF current ratios of the devices were both around 106 in the ambient atmosphere. The mechanisms associated with the memory effect were further elucidated from the density functional theory (DFT) method at the B3LYP level with the 6-31G(d) basis set. The present study suggested that the tunable switching behavior could be achieved through the appropriate design of the donor–acceptor PIs structure to have potential applications for memory devices.

Fabrication of a large scale transparent conducting film using transformed few-layered graphene nanoribbons obtained from unzipping of single wall carbon nanotubes by Woo Sik Kim; Yong Il Kim; Hui Jin Kim; Ji Young Hwanag; Sook Young Moon; No-Hyung Park; Kwang Bo Shim; Hyoun Woo Kim; Heon Ham; Hoon Huh (pp. 15655-15659).
A large scale transparent conducting film has been fabricated using transformed few-layered graphene nanoribbons (FGNRs) obtained from unzipping of single wall carbon nanotubes and poly(3,4-ethylenedioxythiophene). FGNRs are fabricated from an unzipping process of single-walled carbon nanotubes with a high direct current pulse through a pulsed current sintering process. From control of the film thickness and conductivity, the optical transmittance values of films at a wavelength of 550 nm were 84% and 92%, and have sheet resistances of 150 and 2000 Ω sq−1. High resolution transmission electron microscopy, high resolution Raman spectroscopy, X-ray photoelectron spectroscopy, transmittance and electrical conductivity were used for the investigation of the FGNRs and FGNR transparent electrodes to characterize the films.

Phosphoric acid-doped cross-linked porous polybenzimidazole membranes for proton exchange membrane fuel cells by Cheng-Hsun Shen; Li-cheng Jheng; Steve Lien-chung Hsu; Jacob Tse-Wei Wang (pp. 15660-15665).
Cross-linked porous polybenzimidazole (PBI) membranes were prepared by mixing a low-molecular-weight compound (porogen) and a cross-linker with the polymer to form cross-linked polymer membranes in order to increase the mechanical strength and proton conductivity. SEM images of the cross-section of the porous polymer membranes show the pore size and morphology. The cross-linking by p-xylylene dichloride can effectively improve the mechanical properties of the porous PBI membranes after phosphoric acid doping. The CpPBI-60 membrane, which is doped with 9 moles of phosphoric acid, has a tensile modulus of 0.45 GPa. The good mechanical strength of the cross-linked porous PBI membranes makes them able to hold more phosphoric acid and, consequently, have higher proton conductivity. Fenton's test indicated that the covalently cross-linked structure played an important role in the radical oxidative stability of the porous membranes. The doping level of phosphoric acid in the cross-linked porous PBI membranes showed that the enhanced conductivity was due to the increase of porosity, which results in the increase of acid uptake. Impedance analysis showed that the conductivity of the cross-linked porous PBI membranes could reach 2.1 × 10−2 S cm−1 at 160 °C under anhydrous conditions.

Intrinsically electroactive polyimide microspheres fabricated by electrospraying technology for ascorbic acid detection by Chang-Jian Weng; Yu-Sian Jhuo; Ya-Lun Chen; Chun-Fang Feng; Chi-Hao Chang; Shao-Wen Chen; Jui-Ming Yeh; Yen Wei (pp. 15666-15672).
In this paper, we present the first fabrication of intrinsically electroactive polyimide microspheres (EPS) based on conjugated segments of an electroactive amino-capped aniline trimer (ACAT) of a diamine, 4,4′-(4,4′-isopropylidenediphenoxy)-bis(phthalic anhydride) (BSAA) and a dianhydride. EPS was successfully prepared using electrospraying technology and applied in the detection of ascorbic acid (AA). The particle size of EPS can be controlled by varying the concentration of spraying solution, while the electrocatalysis oxidation properties can be influenced by the different particle sizes of EPS. A sensor constructed using an EPSS (EPS with a small particle size)-modified carbon paste electrode (CPE) was found to show 4.38-fold and 1.81-fold higher electrocatalytic activities towards the oxidation of AA than those constructed using an EPI (electroactive polyimide) thin film and EPSL (EPS with large particles size), respectively.

Self-organized photochromic dithienylcyclopentene organogels by Krishnamurthy Rameshbabu; Lu Zou; Chanjoong Kim; Augustine Urbas; Quan Li (pp. 15673-15677).
A series of photochromic organogelators based on dithienylcyclopentene amides with a phenylene unit as a bridge between the amide and long alkyl chain were synthesized, their gelation behaviors were characterized by rheology, FT-IR, 1H NMR, SEM, optical microscopy, UV-Vis and fluorescence spectroscopy. These organogelator molecules were found to be able to induce gelation in apolar solvents such as benzene, toluene and p-xylene to form entangled networks driven by intermolecular hydrogen bonding together with π–π interactions. Their excellent reversible photochromism with thermal stability in both solution and gel states was observed, and the thermally reversible property in sol–gel transition was exhibited.

Synthesis and structural characterization of nanometric ceria highly dispersed in SBA-15 with oxygen exchange capacity by Juliana Martins de Souza e Silva; Mathias Strauss; Camila Marchetti Maroneze; Ernesto Rezende Souza; Yoshitaka Gushikem; Fernando Aparecido Sigoli; Italo Odone Mazali (pp. 15678-15685).
Nanometric ceria-decorated SBA-15 was prepared using a route involving the impregnation of SBA-15 pores by a solution of cerium(III) 2-ethylhexanoate, followed by its thermal decomposition. According to XRF analysis, the number of successive impregnation–decomposition cycles (IDC) allows control of the CeO2/SiO2 ratio in the final material, and also the tailoring of the nanoparticle size of the fluorite CeO2 nanoparticles supported in the SBA-15, as confirmed by XRD, Raman and UV-Vis spectroscopies. The mean pore size of the SBA-15 decreases with successive IDC, as observed by N2 adsorption–desorption, suggesting that CeO2 nanoparticles are located inside the SBA-15 mesopores, as confirmed by TEM and HRTEM analyses. The degree of oxygen storage capacity (OSC) was measured by the number of hydrogen uptake from the temperature programmed reduction (H2-TPR). It was found that the value of hydrogen uptake of SBA-15 submitted to one IDC corresponds to 3344 μmol of O2 per gram of CeO2, whereas those of SBA-15 submitted to five and ten IDC were 1324 and 2769 μmol of O2 per gram of CeO2, respectively.

A facile approach to the synthesis of high-quality NiO nanorods: electrochemical and antibacterial properties by Thangavelu Kavitha; Haldorai Yuvaraj (pp. 15686-15691).
This report describes a new approach to successfully synthesize high-quality nickel oxide (NiO) nanorods with an average diameter of about 60 nm and a length of less than one micrometre via thermal decomposition of a precursor complex nickel benzoate dihydrazinate at 100 °C. The structural features, crystallinity, purity and morphology of the as-synthesized NiO nanorods were investigated by Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), selected area electron diffraction (SAED) and transmission electron microscopy (TEM). The electrochemical property of the as-synthesized NiO nanorods was investigated to determine their suitability as anode materials for lithium-ion batteries. The nanorod electrode exhibited better reversibility and high capacity. In addition, the nanorods showed good antibacterial properties. The magnetic measurement demonstrated that the NiO nanorods are ferromagnetic and may be used in the fields of MR imaging and magnetic drug delivery.

Covalently-functionalizing synthesis of Si@C core–shell nanocomposites as high-capacity anode materials for lithium-ion batteries by Chunyu Du; Meng Chen; Long Wang; Geping Yin (pp. 15692-15697).
This paper reports the facile fabrication of Si@C core–shell nanocomposites by covalently grafting aniline monomer onto the surface of silicon nanoparticles, followed by a carbonizing process. Our covalently-functionalizing approach can lead to a uniform carbon coating with a tunable thickness and is low cost, environmentally friendly and easily scaled up. The Si@C nanocomposite was employed as an anode material for lithium-ion batteries (LIBs), showing a high initial reversible capacity of >1300 mA h g−1 as well as a good cycling stability. The enhanced performance is attributed to the fact that the uniform and elastic carbon coating can efficiently increase the electronic conductivity and accommodate severe volume changes of the Si particles. This Si@C nanocomposite exhibits great potential as an anode material in LIBs, and the fabrication strategy can be extended to prepare other carbon-coated core–shell nanocomposites.

Superparamagnetic nanosystems based on iron oxide nanoparticles & mesoporous silica: synthesis & evaluation of their magnetic, relaxometric and biocompatability properties by Sakthivel Gandhi; S Venkatesh; Uma Sharma; Naranamanglam R. Jagannathan; Swaminathan Sethuraman; Uma Maheswari Krishnan (pp. 15698-15707).
Mesoporous silica has attracted attention in recent years due to its high surface area, tunable ordered narrow pores and easily modifiable functional groups. In the present work, iron oxide nanoparticles (Fe2O3) were incorporated into the pores and surface of mesoporous SBA–15 (Santa Barbara Amorphous) via a thermal pre-synthesis method. The textural and surface properties were characterized using electron microscopy, X-ray diffraction and nitrogen adsorption–desorption analysis. Due to a reduction in thermal pressure during the synthesis, the textural property of the magnetic silica remained highly ordered. The superparamagnetic property of the synthesized material was confirmed using SQUID–VSM. Cell viability studies were carried out with MC3T3 fibroblast cell lines in the presence and absence of magnetic silica and our results showed no significant change in the cell viability between the concentration range of 31.3 μg mL−1 and 250 μg mL−1. The magnetic resonance properties of the iron oxide doped mesoporous silica was determined using MRI and showed excellent longitudinal (R1) and transverse relaxivities (R2) with an R2/R1 ratio close to 1, indicating the potential of this material as a magnetic contrast agent.

Targeted coadministration of sparingly soluble paclitaxel and curcumin into cancer cells by surface engineered magnetic nanoparticles by S. Manju; C. P. Sharma; K. Sreenivasan (pp. 15708-15717).
This study presents a feasible method for the fabrication of multifunctional magnetic nanoparticles (MNPs) for the targeted coadministration of two anticancer agents, paclitaxel (PTX) and curcumin (CUR). MNPs were first surface modified with N-[3-(trimethoxysilyl)propyl]ethylenediamine to form a self-assembled monolayer and subsequently conjugated with folic acid and carboxymethylcyclodextrin through amidation between carboxy groups of folic acid/carboxymethylcyclodextrin and amine groups on the nanoparticle surface. Drug release studies showed that PTX/CUR was diffused out from the nanoparticle under low pH, mimicking the intracellular conditions in the lysosome and also at pH 7.4. Cellular viability studies proved the efficacy of the coadministration of PTX/CUR and the dose dependent antiproliferative effect in cancer cell lines (HeLa and glioma cells). The modified nanoparticles were also found to be highly blood compatible indicating their suitability for in vivo applications. In vitro evaluations reflected that owing to the enhanced targeting ability, the newly designed multifunctionalized MNPs can be used as vectors for the coadministration of anticancer agents which may be effective in defending multidrug resistance.

Controlled synthesis and photoelectric application of ZnIn2S4 nanosheet/TiO2 nanoparticle composite films by Shengjie Peng; Yongzhi Wu; Peining Zhu; Velmurugan Thavasi; Seeram Ramakrishna; Subodh G. Mhaisalkar (pp. 15718-15726).
This paper reports the controlled synthesis of ZnIn2S4 nanosheet/screen-printed TiO2 nanoparticle composite films by a facile hydrothermal method and demonstrates the photoelectric application of ZnIn2S4 nanosheets as potential inorganic sensitizers in semiconductor-sensitized solar cells. The ZnIn2S4 nanosheets with a thickness of about 20 nm and a lateral size of 2 μm were distributed not only on the surface but also in the interior of the TiO2 nanoparticles, indicating a full contact between ZnIn2S4 nanosheets and TiO2 nanoparticles. The ZnIn2S4/TiO2 composite films demonstrated bandgap energy values ranging from 2.38–2.64 eV and their peaks can shift from the ultraviolet region to the visible region, compared with that of the TiO2/FTO film (FTO: fluorine-doped tin oxide). The densities, thicknesses, morphologies of the ZnIn2S4 nanosheets could be controlled by adjusting the experimental parameters, including reaction times, temperatures and concentrations. The possible formation mechanism and growth process of the ZnIn2S4 nanosheets on the TiO2 nanoparticles were discussed based on the experimental results. Furthermore, as a proof-of-concept, ZnIn2S4/TiO2-based inorganic semiconductor-sensitized solar cells were fabricated by filling polysulfide liquid electrolyte into the electrodes and the device exhibited a reproducible photovoltaic response.

Synthesis and characterization of thianthrene-based poly(phenylene sulfide)s with high refractive index over 1.8 by Yasuo Suzuki; Kimiya Murakami; Shinji Ando; Tomoya Higashihara; Mitsuru Ueda (pp. 15727-15731).
Highly refractive thianthrene-based poly(phenylene sulfide)s (TPPSs) have been developed. The TPPSs were prepared from 2,7-difluorothianthrene and dithiols, including 4,4′-thiobisbenzenethiol (TBBT), m-benzenedithiol (mBDT), or sodium sulfide nonahydrate based on aromatic nucleophilic substitution reactions, and showed excellent thermal stabilities such as relatively high glass transition temperatures in the range of 143–147 °C and 5% weight-loss temperatures over 430 °C. All of the TPPSs exhibited very high refractive indices reaching 1.8020 along with a high transparency in the visible region and low birefringence in the range of 0.0037–0.0039.

The effect of 1-N-alkyl chain of ionic liquids [Cnmim]+Br (n = 2, 4, 6, 8) on the aspect ratio of ZnO nanorods: syntheses, morphology, forming mechanism, photoluminescence and recyclable photocatalytic activity by Li Wang; Li-Xian Chang; Lian-Qiang Wei; Shen-Zhi Xu; Ming-Hua Zeng; Shi-Lie Pan (pp. 15732-15740).
Using a pure ionic liquid-assisted solid-state-like synthesis method under 80 °C, high quality zinc oxide (ZnO) nanorods in 1-alkyl-3-methylimidazolium and bromide anions ionic liquids [Cnmim]+Br (n = 2, 4, 6, 8) were realized. The size effect of the N-alkyl chains of ionic liquids hindered the further growth of ZnO nanorods and the aspect ratio (length/diameter, L/D) of ZnO nanorods (from 40 : 1, 20 : 1, 10 : 1, to 5 : 1) were realized by rationally tuning the length of the organic cation groups. Long octyl chains (9.93 Å) resulted in short ZnO nanorods (with L/D = 5 : 1), otherwise, short ethyl chains (2.53 Å) resulted in long ZnO nanorods (with L/D = 40 : 1). The growth mechanism of the above ZnO nanorods was mainly due to electrostatic interactions between cations of the ionic liquids and the ZnO crystal nucleus, causing the preferential growth on the [0001] directions of the hexagonal ZnO. The as-obtained short ZnO nanorods (with L/D = 5 : 1) exhibited defect-related green-yellow emission under UV excitation, and acted as effective recyclable photocatalysts during six photodegradation cycles of the organic dye molecule Rhodamine B, suggesting promising potential for environmental applications. This systematic study highlighted that the structures and morphology of ZnO nanomaterials could be controllable via specifically varying the molecular structure of 1-alkyl-3-methylimidazolium cation-based ionic liquids, and then with the tuned photocatalytic properties and optical and electronic functions of them.

Molecularly imprinted polymers based on magnetic fly-ash-cenosphere composites for bisphenol A recognition by Jianming Pan; Wei Hu; Xiaohui Dai; Wei Guan; Xiaohua Zou; Xue Wang; Pengwei Huo; Yongsheng Yan (pp. 15741-15751).
Magnetic composites (MCs) were achieved via coating a chitosan layer containing γ-Fe2O3 nanoparticles onto the surface of aldehyde-functionalized fly-ash-cenospheres. Based on these MCs, the magnetic molecularly imprinted polymers (MMIPs) were further synthesized and characterized, and used to selectively recognise bisphenol A (BPA) molecules. Owing to the intrinsic advantages of cross-linked chitosan, magnetic γ-Fe2O3 nanoparticles and spherical FACs, the results demonstrated that these spherical shaped MMIPs particles had magnetic sensitivity (Ms = 2.221 emu g−1) and magnetic stability (especially over the pH range of 6.0–12). Batch mode adsorption studies were carried out to investigate the specific adsorption equilibrium, kinetics and selective recognition. The Langmuir isotherm model was fitted well to the equilibrium data of the MMIPs, and the monolayer adsorption capacity of the MMIPs was 135.1 mg g−1 at 298 K. The kinetic properties of the MMIPs were well described by the pseudo-second-order equation, indicating the chemical process could be the rate-limiting step in the adsorption process for BPA. Selective recognition experiments demonstrated the high affinity and selectivity of MMIPs towards BPA over competitive phenolic compounds. The molecular interaction between BPA and methacrylic acid (MAA) was investigated by the 1H-NMR spectrum. Hydrogen bonding was proved to be mainly responsible for the recognition mechanism, and the specific recognition effect may be based on the distinct size, structure and functional group of the template molecules.

Physical properties of poly(vinylidene fluoride) composites with polymer functionalized multiwalled carbon nanotubes using nitrene chemistry by Amit Mandal; Arun K. Nandi (pp. 15752-15763).
Poly(methyl methacrylate) (PMMA) functionalized multi-walled carbon nanotubes (MWNT) (f-MWNT) are prepared using nitrene chemistry and atom transfer radical polymerization. The >CO groups in the f-MWNT interact with the >CF2 groups of poly(vinylidene fluoride) (PVDF) to achieve a compatible blend. An increase of the glass transition temperature (Tg), relaxation temperatures of the crystal-amorphous interface and crystalline phases are observed in the composites over pristine PVDF. The thermal stability of the composites increases with increasing f-MWNT concentration. The storage modulus increases significantly with increasing f-MWNT concentration and the highest increase of 120% over PVDF is observed for 1 wt% f-MWNT at 50 °C. An increase in tensile strength with a decrease of the strain at break, and increase of Young's modulus and toughness indicate the formation of a very hard and ductile composite material. The electrical conductivity is high (1 × 10−4 S cm−1, for 5% f-MWNT) and shows a very low percolation threshold (0.36% w/w at 30 °C). Analysis of the conductivity data yields the magnitude of percolation exponent 2.1, suggesting three-dimensional percolation is a suitable model for the conduction of the composites. The temperature variation of the conductivity suggests that the conduction might occur through a temperature fluctuation induced tunnelling mechanism. The IV characteristic curves indicate the semiconducting nature of the composites.

Solventless thermal decomposition of ferrocene as a new approach for the synthesis of porous superparamagnetic and ferromagnetic composite microspheres of narrow size distribution by Daniel Amara; Shlomo Margel (pp. 15764-15772).
In previous publications we described various methods to prepare ferromagnetic poly(divinylbenzene)/iron oxide and C/iron oxide composite microspheres for various biomedical applications. However, these particles suffer from a few significant shortcomings, such as the high toxicity of the precursor (iron pentacarbonyl) used for obtaining the magnetic particles, broad size distribution, etc. In addition, superparamagnetic particles could not be obtained by the previous methodology. The present work describes a new approach to overcome these obstacles. Superparamagnetic poly(divinylbenzene)/iron oxide composite microspheres of narrow size distribution were prepared by entrapping ferrocene and separating media within the pores of uniform porous PDVB microspheres, followed by the solventless thermal decomposition at 300 °C in ambient atmosphere in a sealed cell. Uniform ferromagnetic C/iron oxide and C/Fe3O4/Fe composite microspheres were then formed by annealing the superparamagnetic PDVB/iron oxide particles at 500 and 700 °C, respectively, under argon atmosphere.

Red electroluminescent polyfluorenes containing highly efficient 2,1,3-benzoselenadiazole- and 2,1,3-naphthothiadiazole-based red dopants in the side chain by Lei Chen; Hui Tong; Zhiyuan Xie; Lixiang Wang; Xiabin Jing; Fosong Wang (pp. 15773-15779).
By attaching small amounts of highly efficient D-A-D′-type 2,1,3-benzoselenadiazole and 2,1,3-naphthothiadiazole derivatives to the side chain of a polyfluorene host, we developed two series of red polymers, PFR-xBS and PFR-xNT. By tuning the doping concentration, complete energy transfer from the PF host to the red dopant occurs. The EL spectra of these red polymers show predominantly a red emission, attributed to the dopants. Single-layer devices (ITO/PEDOT:PSS/polymer/Ca/Al) of red polymers realized pure red light with a peak at 620 nm, a luminous efficiency of 2.91 cd A−1 and CIE coordinates of (0.62, 0.36) for PFR-10BS, and a saturated red light with a peak at 632 nm, a luminous efficiency of 3.04 cd A−1 and CIE coordinates of (0.63, 0.35) for PFR-10NT, respectively. To the best of our knowledge, the device performance of PFR-10NT is among the best single-layer saturated red PLEDs based on fluorescent polymers.

Distribution-enhanced direct electron communication of hemoglobin immobilized in pristine TiO2 nanotube arrays by Zhe An; Yan Wang; Jing He (pp. 15780-15787).
In this work, efficient direct electron transfer (eT) has been achieved for hemoglobin (Hb) immobilized in pristine TiO2 nanotube arrays (TNAs) through controlling Hb distribution. Confocal laser scanning microscope (CLSM) and field emission scanning electron microscopy (FESEM) studies confirm that Hb is distributed inside the TiO2 nanopores in a nearly uniform monolayer. The peak-to-peak separation (ΔEp) is measured as 57 mV and the apparent heterogeneous eT rate constant (ks) is calculated as 1.365 s−1, both superior to that reported previously. A novel one-electron two-proton reaction mechanism has been proposed to explain the distribution-enhanced direct eT. The enhanced eT is well displayed on the Hb-in-TNAs based H2O2 sensor, which exhibits a sensitivity of as high as 0.919 mA mM−1 cm−2, a detection limit of as low as 7.0 × 10−8 M at a signal-to-noise of 3, and a wide linear detection range from 10−8 to 10−3 M.

Polymer end-group mediated synthesis of well-defined catalytically active platinum nanoparticles by Lauren M. Forbes; Aoife M. O′Mahony; Sirilak Sattayasamitsathit; Joseph Wang; Jennifer N. Cha (pp. 15788-15792).
Simple, short polyethyleneglycol (PEG) chains were found to mediate the synthesis of well-defined 7–8nm cubic and truncated cubic platinum (Pt) particles that required only mild ligand removal conditions to yield highly active catalysts for the oxygen reduction reaction (ORR). FTIR analyses showed that only the hydroxyl end groups of the PEG chains associate with the platinum particles, which oxidize readily to form carbonyl groups with weaker interactions with the platinum surface. ORR analysis showed a mass activity of 50 μA μg−1 for the PEG synthesized Pt nanoparticles (NPs), as compared to a mass activity of 45 μA μg−1 for platinum black. The half-wave potentials of PEG Pt NPs and Pt black were found to be 427 mV and 529 mV, respectively, showing a high catalytic activity of PEG Pt NPs towards ORR. Well-defined particles were also produced from amine-terminated PEG, but as the amines could not be removed by simple acid washing, the ORR activity was greatly diminished. Since short low molecular weight PEG was found to control particle nucleation and growth predominantly through its end groups, this work demonstrates that PEG is a versatile scaffold from which to screen a wide variety of functional moieties, including biomolecules, as templates for complex nanoparticle synthesis.

Robust superhydrophobic surfaces with mechanical durability and easy repairability by Xiaotao Zhu; Zhaozhu Zhang; Xuehu Men; Jin Yang; Kun Wang; Xianghui Xu; Xiaoyan Zhou; Qunji Xue (pp. 15793-15797).
Development of superhydrophobic self-cleaning materials is hindered by their susceptibility to mechanical abrasion. Here, to solve the problem caused by mechanical damage, we prepared a superhydrophobic metal/polymer composite surface possessing both mechanical durability and easy repairability. The mechanical durability of the resulting superhydrophobic surface was evaluated by the abrasion test. The result demonstrated that the rough surface textures were retained and the surface still exhibited superhydrophobicity after mechanical abrasion. Moreover, the non-wetting property can be restored by an easy regeneration process when loss of superhydrophobicity occurs. Amazingly, the created metal/polymer surface can be used as a finger touchable self-cleaning surface.

New topotactic synthetic route to mesoporous silicon carbide by Peng-Cheng Gao; Yannick Lei; Andrès F. Cardozo Pérez; Khalil Rajoua; David Zitoun; Frédéric Favier (pp. 15798-15805).
Mesoporous silicon carbide (SiC) was synthesized by a one-pot thermal reduction of SiO2/C composites by metallic Mg at the remarkably low temperature of 800 °C. Two distinct mesostructured silica were used as hard templates for composite preparation: a hexagonal 3D close-packed assembly of Stöber silica spheres and an ordered mesoporous SBA15 silica. In the latter case, SiC has crystallized in its 2H–SiC hexagonal phase, which is rather unique at such a low temperature. Composites were obtained by impregnation/polymerisation/carbonisation of a molecular carbon precursor within the porous structure of the silica template. After thermal treatment at a moderate temperature in the presence of Mg and subsequent by-products rinsing off, both prepared SiC showed distinct mesoporous structures related to the initial SiO2 architectures. By comparison of the mesoporous characteristics, resulting SiC was found to retain the carbon structures of the pristine composites. The description of the synthetic mechanism of this topotactic reaction contrasts with the usual assumption stating the templating role of silica.

Rutile nanowire arrays: tunable surface densities, wettability and photochemistry by Qiang Zhou; Xianfeng Yang; Shanqing Zhang; Yaxiong Han; Gangfeng Ouyang; Zhenhui He; Chaolun Liang; Mingmei Wu; Huijun Zhao (pp. 15806-15812).
In this work, we report a facile and environmentally friendly hydrothermal route to directly grow nanostructured TiO2 arrays on cheap titanium metal foil with tunable surface morphologies without using any catalysts, seeds or templates. Their crystal structure and morphology were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and fast Fourier transform (FFT). The rutile TiO2 nanoarrays, growing along the [001] direction, consist of highly ordered nanowires (nanorods) rooting at the titanium substrate. The controlled growth of nanoarray films with different nanostructures, including nanowires, nanorods and nanocolumns, can be achieved by adjusting the key experimental parameters, such as growth time, reaction temperature and HCl concentration. Subsequently, the surface morphologies and wettability can be readily tuned. A possible growth mechanism is proposed based on a series of pieces of experimental evidence. The photoelectrochemical properties of the as-prepared rutile nanoarray films were investigated in detail. The photocurrent seems related to the surface morphology of the examined photoanode.

Size and shape controlled LiMnPO4 nanocrystals by a supercritical ethanol process and their electrochemical properties by Dinesh Rangappa; Koji Sone; Ying Zhou; Tetsuichi Kudo; Itaru Honma (pp. 15813-15818).
In this paper, we report the preparation of systematically size and shape controlled LiMnPO4 nanocrystals under supercritical fluid conditions. The effect of different reaction conditions such as the reaction time, temperature, surfactant and precursor concentration on the size and shape of the LiMnPO4 nanocrystals was studied in detail. It was noticed that shorter reaction time and lower reaction temperature facilitated the formation of crystalline LiMnPO4 nanocrystals with size ∼10 nm. The nanocrystals ranging from 7 to 24 nm were obtained by controlling different reaction conditions. The formation mechanism for the LiMnPO4 nanocrystals is proposed based on the obtained results. The effect of nanosize on the electrochemical properties of LiMnPO4 nanocrystals was studied. Improved electrochemical performance was observed for ∼20 nm sized LiMnPO4 after conductive carbon coating. This study indicates the importance of LiMnPO4 nanocrystals below 50 nm size in improving the electrochemical performance of LiMnPO4 cathodes.

Back cover (pp. 15819-15820).
This report surveys the 2010 literature on mechanisms of pericyclic reactions. Among the newer concepts highlighted in this year's studies are the distortion-interaction model of reactivity, the importance of CH-π interactions in controlling selectivity, and the catalysis of pericyclic reactions by transition metals and organocatalysts. This year, a substantial number of (4+3) cycloadditions and dyotropic rearrangements were examined; these reactions have received limited attention in the past.
Featured Book
Web Search

Powered by Plone CMS, the Open Source Content Management System

This site conforms to the following standards: