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Silicon carbide nanopowders (SiC_PL) were prepared via thermal plasma synthesis. The electrocatalytic activity of the SiC_PL coated glassy carbon electrode (GCE) towards the electrochemical oxidation of dopamine (DA), ascorbic acid (AA), and uric acid (UA), was characterized by cyclic voltammetry (CV), in 0.1 M phosphate buffer solution (PBS) at pH 7. The peaks of oxidation for DA, AA, and UA result well separated on the modified electrode in contrast with the behavior shown on bare GCE. A low limit of detection (LOD) of 0.043 μM was found at the SiC_PL coated GCE. In a real sample, the recovery rates of the added compound were 98.8%, 106.5% and 100.7%, indicating a potential for the SiC_PL electrode to determine DA in real conditions. The results of the characterization as supercapacitor electrode show that the specific capacitance for SiC_PL is of 151.2 F/g at 0.12 A/g. After 2.5 × 105 cycles SiC electrode still retains about 90% of its initial capacitance showing good stability.

A novel study about the synthesis of zirconia and calcia-stabilized zirconia powders were carried out by DC thermal plasma starting from cheap precursors as the carbonates. Different operational parameters were investigated to explore the effects of the process conditions, such as the plasma torch power and the gas flow rate on the composition and the morphology of the powders. The products phase changes from a metastable tetragonal to monoclinic/tetragonal mixture. Basically a main tetragonal phase was obtained at low torch power (7 kW) while the amount of monoclinic phase linearly rises with the power, up to 66 wt% at 26 kW of plasma power and high gas flow rate. The gas flow rate also affects the shape and the size of the powder, where high values reduce powder aggregation and enhance the spherical shape. The best results were achieved at 22 kW of plasma power and high gas flow rate, with powders of roundness about 79% and a wide particle size distribution. Adding the calcium carbonate to the zirconium carbonate (corresponding to 8 wt% CaO in the final mixture), the plasma treatment mainly produces a tetragonal phase zirconia, that at 1400 °C in furnace changes in a stable cubic phase. These powders could be made suitable for further industrial applications after proper treatments.

Pyroelectric energy harvesting is one of the more recent and promising solid-state approaches for directly converting time-dependent temperature fluctuations into electric energy. Conventional printing technologies can offer many advantages for the production of pyroelectric thin-film-based devices, such as low cost, low temperature, the use of flexible substrates and shaping at the same time as deposition. Nevertheless, some issues related to low printed thickness and film-forming microstructure control need to be addressed. In this exploratory study, the possibility of exploiting the highly attractive gravure printing process for the potential industrial manufacture of flexible polyvinylidene fluoride (PVDF) thin-film pyroelectric devices was investigated. By the use of corona pre-treatment of the printing substrate and low-temperature polar solvent evaporation, multilayer gravure-printed PVDF pyroelectric devices were successfully manufactured for the first time, achieving a maximum generated current of 0.1 nA at 2.5 K/s from a device with an active area of 1 cm2. Considering the very low thermal inertia and performance scaling by the area expected for pyroelectric thin-film-based devices, combined with the upscaling potential of roll-to-roll gravure printing, our results provide new opportunities for on-demand, low-cost pyroelectric device manufacture and their integration in hybrid harvesters.

Tungsten disulfide (WS2) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS2 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS2 nanocomposite films varying the concentration of WS2 NTs from 0 (neat PLA) to 0.6 wt%. The films were uniaxially drawn at 90 °C and annealed at the same temperature for 3 and 10 min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS2 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6 wt% of WS2 induces the same level of crystallinity in as stretched PLA-WS2 as annealing in neat PLA for 10 min. These data provide useful insights into the role of WS2 NTs on the structural evolution of PLA-WS2 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.

Treatment of vascular disease, from peripheral ischemia to coronary heart disease (CHD), is poised for transformation with the introduction of transient implants designed to "scaffold" regeneration of blood vessels and ultimately leave nothing behind. Improved materials could expand the use of these devices. Here, we examine one of the leading polymers for bioresorbable scaffolds (BRS), polylactide (PLA), as the matrix of nanocomposites with tungsten disulfide (WS2) nanotubes (WSNT), which may provide mechanical reinforcement and enhance radio-opacity. We evaluate in vitro cytotoxicity using vascular cells, flow-induced crystallization and radio-opacity of PLA-WSNT nanocomposites at low WSNT concentration. A small amount of WSNT (0.1 wt%) can effectively promote oriented crystallization of PLA without compromising molecular weight. And radio-opacity improves significantly: as little as 0.5 to 1 wt% WSNT doubles the radio-opacity of PLA-WSNT relative to PLA at 17 keV. The results suggest that a single component, WSNT, has the potential to increase the strength of BRS to enable thinner devices and increase radio-opacity to improve intraoperative visualization. The in vitro toxicity results indicate that PLA-WSNT nanocomposites are worthy of investigation in vivo. Although substantial further preclinical studies are needed, PLA-WSNT nanocomposites may provide a complement of material properties that may improve BRS and expand the range of lesions that can be treated using transient implants. STATEMENT OF SIGNIFICANCE: Bioresorbable Scaffolds (BRSs) support regeneration of arteries without permanent mechanical constraint. Poly-L-lactide (PLLA) is the structural material of the first approved BRS for coronary heart disease (ABSORB BVS), withdrawn due to adverse events in years 1-3. Here, we examine tungsten disulfide (WS2) nanotubes (WSNT) in PLA to address two contributors to early complications: (1) reinforce PLLA (enable thinner BRS), and (2) increase radiopacity (provide intraoperative visibility). For BRS, it is significant that WSNT disperse, remain dispersed, reduce friction and improve mechanical properties without additional chemicals or surface modifications. Like WS2 nanospheres, bare WSNT and PLA-WSNT nanocomposites show low cytotoxicity in vitro. PLA-WSNT show enhanced flow-induced crystallization relative to PLA, motivating future study of the processing behavior and strength of these materials.

In this work, the introduction of small variations in the electrical impedance ofHF (High Frequency) RFID (Radio Frequency Identification) tags has been exploited in the proximity sensing of temperature by applying Polyvinylidene Fluoride (PVDF) interdigital capacitive sensors as a modification of the transponder’s circuitry. The adopted electrical parasitic sensing load introduces a shift in the primary resonance peakof the tag. Theimpedance spectra have been acquired by a dedicated laboratory setup allowing to apply simultaneously thermal forcing and RF signals to the transponder itself. Thesensitivity of the modified taghas been assessed after taking into account the thermal response of the transponder chipwhich is relevant in the formulation of thermal-sensing transponders.

This work shows a method to fabricate interdigital capacitors having tunable sensitivity to temperature and stable behavior pointing to the application of ionic liquids (ILs) as fundamental building blocks in capacitive devices for temperature sensing in proximity conditions. Polyvinylidene fluoride (PVDF) in blend with 1-Butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) has been deposited by drop-casting from a N,N-dimethylformamide solution to be utilized as dielectric material in screen-printed interdigitated capacitors. Capacitance and conductance trends versus temperature have been analyzed and compared to bare PVDF dielectrics. The inclusion of [BMIM][PF6] in PVDF-IL blends increases the AC capacitance of the device and its sensitivity to the temperature in the examined range (+20 °C to +110 °C). AC measurements performed at 100 kHz have shown good electrical stability for PVDF-IL blends also when measured in ambient atmosphere. As a drawback, an increase in [BMIM][PF6] concentration resulted also in an increase in AC conductance which exhibits an Arrhenius activation with temperature. Such behavior has been attributed to the increase in ion concentration and ionic mobility with temperature. The work also shows the presence of a limit value for the activation energy of AC conductance for higher concentrations of the ionic liquid.

The development of complete organic/inorganic hybrid solar cells (HOSCs) is strictly related to the achievement of appealing electrical performances. In this context, the optimization of device architectures and of the active material's structural and morphological properties is crucial. In this work, such highly critical issues are addressed for a novel hybrid nanocomposite: tungsten disulfide nanotubes (WS2 NTs) and cadmium selenide quantum dots (CdSe QDs) embedded into a Poly (3-hexylthiophene-2,5-diyl) (P3HT) polymeric matrix. Both binary and ternary compounds are produced and investigated by means of an unconventional energy-dispersive X-ray diffraction technique combined with atomic force microscopy and Raman spectroscopy. Additionally, the effects of low-temperature thermal treatments on the nanocomposite's structure and morphology are disclosed, unraveling their connection of these features to the optical response of the materials, investigated by UV-Vis spectroscopy. Promising results are obtained in terms of enhanced crystallinity, phase separation, and the possibility of decorating the WS2 NTs with CdSe dots is demonstrated, opening new perspectives for further development of complete HOSCs based on this innovative ternary system.

Carbon nanotubes-grafted-carbon fibers have been tested to improve composite performances; in particular in aerospace this substrate was tested as conductive light material in substitution of metallic foils. In this work, hierarchical growth of carbon nanotubes (CNTs) has been achieved on recovered carbon fiber (rCF). The process has been performed by thermal catalytic chemical vapour deposition (CCVD) starting from liquid precursor (such as ethanol); different combinations of process parameters were tested and the growth was verified by Scanning Electron Microscopy (SEM) and Raman Spectroscopy. The electrical characterization of the samples shows an increase of conductivity in presence of CNTs. © 2018 Author(s).

We report our work about OLED devices where the emissive layer is based on CdSe/ZnS quantum dots (QDs) combined with poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT) in two different ways: blends at various QDs concentrations and sequential deposition of QDs and F8BT layers. The fluorescence of the blends presents a wide emission in the range (500-700) nm due to the combination of fluorescence by the polymer (maximum at 540 nm) and QDs (maximum at 634 nm). Among the layered structures, the fluorescence emission by the QDs substantially contributes to the spectrum only for the F8BT/QDs bilayer. The OLEDs devices realized with the blend at 15 wt% of QDs show the highest luminance respect to all the devices, and threshold voltage values similar to the neat polymer device. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In this work, FETs are used as a research tool to study charge carrier mobilities in PbS nanocrystals (NCs) thin-films employed as semiconducting layer in bottom-gate bottom-contact (BGBC) field-effect transistors (FETs). The as-synthesised NCs are surrounded by long alkyl chain ligands which act as electrical insulators. Therefore, a ligand exchange process with shorter molecules is necessary to enhance the free charges generation and transport. We used two different ligands: 1,2 ethandithiol (EDT) and 1,2,3,4-tetrabutylammonium iodide (TBAI) and studied the charge mobility of PbS NCs comparing the electrical characteristics of FETs made by exchanged NCs. We analysed also the contemporary presence of both exchanged nanocrystals on the device. All the transistors showed p-type transport behaviour, enhanced by an annealing process at 100 °C for 10 min. After this, only the TBAI-treated NCs devices showed a n-type transport, resulting in an ambipolar behaviour. Inkjet printing deposition techniques was also successfully used to deposit PbS-(TBAI) NCs and ambipolar devices were obtained. In addition, for printed devices it was found that it is possible to modulate the charge transport properties by applying surface treatment to the substrate with a pentafluorothiophenol (PFTP). Indeed in this case, the p-type transport was suppressed while n-type behaviour was induced.

POC polymer is an oxadiazole-carbazole copolymer we have previously synthetized and established as light emitting material in Organic Light Emitting Devices (OLEDs), although POC quantum yield emission efficiency and color purity still need to be enhanced. On the other hand, tris[2-phenylpyridinato-C2,N]iridium(III) (Ir(ppy)3) complexes, namely Ir(ppy)3 are among the brightest luminophores employed in green light emitting devices. Our aim, in this work, is to take advantage of Ir(ppy)3 bright emission by combining the Ir complex with blue emitting POC to obtain tunable light emitting composites over a wide range of the visible spectrum. Here we have investigated the optical proprieties POC based nanocomposites with different concentrations of Ir(ppy)3, ranging from 1 to 10 wt%. Both spectral and time resolved fluorescence measurements show an efficient energy transfer from the polymer to the dopants, resulting in white-emitting composites. The most intense and stable emission has been found when POC was doped with about 5 wt% concentration of Ir(ppy)3. © 2016 Elsevier B.V.

Many research efforts are focused toward significant improvements of polymeric solar cells efficiency, energy harvesting range, time, and environmental stability. Particular attention is given to hybrid organic/inorganic composites constituted of polymer/lead chalcogenides (PbS and PbSe) nanocrystals (NCs) to extend the spectral sensitivity of cells to near-infrared wavelengths. In this work we report the synthesis and characterization of PbS nanocrystals with absorption edge at 984 nm. The nanocrystals have a cubic crystal structure and size of about 2 nm as found by X-ray diffraction analysis. They were combined with poly(3-hexylthiophene) (P3HT) polymer to obtain P3HT:PbS blends with different PbS loadings. A post-deposition ligand exchange on PbS NCs by 1,2-ethanedithiol (EDT) allowed a better interaction between polymer and nanocrystals as showed by fluorescence measurements. The P3HT:PbS blends were deposited and treated by a layer by layer spin coating process and used as active layer in solar cells having structure glass/ITO/PEDOT:PSS/blend/Al. The major result obtained for this hybrid system is an increase of PCE by about two orders of magnitude with respect to analogous reported cells where a post-deposition ligand exchange was performed.

The prospect of exploiting quantum dots (QDs) properties (tunable absorption spectrum, multiple exciton generation) while maintaining the flexible structure of polymer systems opens new possibilities in the photovoltaic field. Although charge transport dynamics in pristine polymer and QDs systems have been quite well established lately, a complete understanding of the charge transfer process between QDs and polymers when they are in blends is still lacking. In this work we used static and ultrafast fluorescence spectroscopy together with Atomic force Microscopy (AFM) to study the exciton dynamics in polymer/QDs films. Specifically we used poly(3-hexylthiophene) (P3HT) as the hole conducting donor material and the core shell CdSe(ZnS) QDs as the electron acceptor material. The QDs surface has been treated with two different capping ligands treatments: one based on the use of pyridine and the other one on hexanoic acid. The influence of the two different methods on the exciton dynamics and on the morphology will also be discussed. Blends containing differently treated P3HT/CdSe(ZnS) wt% ratios have been prepared producing films having uniform morphology and good intermixing, as proved by AFM measurements. Ultrafast fluorescence decays allowed us to compare the exciton dynamics in the polymer pristine respect to the treated P3HT/CdSe(ZnS) films. Efficient fluorescence quenching has been shown by both kind of blends respect to the pure polymer. © 2014 The Authors.

New chiral P,N-chelates o-Ph2PC6H4CHNR (R=carbohydrate residue) derived from d -glucose and d -mannose were described. The synthesis of palladium(0) and rhodium(I) complexes of respective formula [Pd(P,N-chelate)(fumarodinitrile)] and [Rh(1,5-cyclooctadiene)(P,N-chelate)]BF4 was performed. It was found that the ligands effectively discriminate between the enantioface of fumarodinitrile in the Pd(0) species, prompting up to 100% diastereomeric excess when R is a 2,3,4-tri-O-acetylated glucoside moiety linked to N through C6. The catalytic activity of the complexes towards allylic alkylation and olefin hydroboration was also examined.

Blends of conductive polymer poly(3-hexylthiophene) (P3HT) and size controlled MoS2 nanotubes (NTs) were prepared focusing on procedures which do not alter the electrical and optical properties of nanotubes, i.e., without surfactants. After disassembly of as-grown hedgehog-like self-assemblies of the MoS2 NTs, relatively homogeneous dispersions of the NTs in P3HT were prepared. Thin films of these blends were prepared via spin coating. The NTs were found efficiently wetted by the P3HT and nearly completely immersed in the films. The surface structure was composed of pure P3HT lamellae. Photoluminescence spectra taken on P3HT/MoS2 NT thin films revealed a quenching effect, which depends on the concentration of NTs. Results of optical microscopy and spectroscopy investigations, scanning tunnelling microscopy and scanning electron microscopy studies are shown.

New chiral diimino and diamino ligands derived from α- d -mannose and α- d -glucose are described. The ligands are obtained by introducing the appropriate nitrogen functions at C(2) and C(3) of the sugar rings. The ability of the new chelates to promote the asymmetric copper(I)-catalysed cyclopropanation of styrene has been investigated. The nature of both the sugars and the chelates is crucial in determining the enantioselectivity of the reaction.

This paper describes a straightforward strategy for the synthesis of new nitrogen chelates by employing the chirality of readily available sugars. Thus, diimino and diamino ligands can be attained easily by using the methyl-4,6- O -benzylidene-2,3-diazo-2,3-dideoxy-α- d -mannopyranoside skeleton. The coordinating ability of one ligand has also been assessed by preparing a square-planar palladium complex [PdCl 2 ( N , N -chelate)].

The integration of semiconductor nanoparticles (NPs) into a polymeric matrix has the potential to enhance the performance of polymer-based solar cells taking advantage of the physical properties of NPs and polymers. We synthesize a new class of CdS-NPs-based active layer employing a low-cost and low temperature route compatible with large-scale device manufacturing. Our approach is based on the controlled in situ thermal decomposition of a cadmium thiolate precursor in poly(3-hexylthiophene) (P3HT). The casted P3HT:precursor solid foils were heated up from 200 to 300 °C to allow the precursor decomposition and the CdS-NP formation within the polymer matrix. The CdS-NP growth was controlled by varying the annealing temperature. The polymer:precursor weight ratio was also varied to investigate the effects of increasing the NP volume fraction on the solar cell performances. The optical properties were studied by using UV–Vis absorption and photoluminescence (PL) spectroscopy at room temperature. To investigate the photocurrent response of P3HT:CdS nanocomposites, ITO/P3HT:CdS/Al solar cell devices were realized. We measured the external quantum efficiency (EQE) as a function of the wavelength. The photovoltaic response of the devices containing CdS-NPs showed a variation compared with the devices with P3HT only. By changing the annealing temperature the EQE is enhanced in the 400–600 nm spectral region. By increasing the NPs volume fraction remarkable changes in the EQE spectra were observed. The data are discussed also in relation to morphological features of the interfaces studied by Focused Ion Beam technique.

In this work, a simple approach to prepare luminescent poly(3-hexylthiophene)–CdS nanocomposites to be employed in organic light emitting devices (OLED) devices is reported. The nucleation and growth of CdS nanoparticles were obtained by the thermolysis of a single Cd and S precursor dispersed in the polymer at three different temperatures of annealing: 240, 265, and 300°C. In this way, it was possible to compare the properties of nanocomposites containing nanoparticles with different sizes. X-ray diffraction and transmission electron microscopy analyses confirmed the formation of CdS nanoparticles and gave information about the size, distribution, and morphology of the nanoparticles; monodispersive and very small nanoparticles with diameters below 2.5 nm were obtained at 240°C. The application of such nanocomposites as emitting layers in OLED devices is discussed. Enhanced electrooptical properties were observed for the device containing the nanocomposite annealed at 240°C with respect to the pure polymer based device. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Commercially available Sodium clay (Dellite HPS) and organo-clay (Dellite 72T) are modified via a silylation reaction. These silylated clays are characterized by IR, XRD, thermogravimetric analyses, and their equilibrium contact angles are measured. They are used to prepare nanocomposites at different loading percentage (1, 3, 5% wt) by in situ intercalative polymerization of Methyl methacrylate and morphology and thermal properties of nanocomposites are examined. SEM images of nanocomposites fractured surface show the absence of clays aggregates, confirming a good dispersion and distribution of montmorillonites in the polymer matrix. The effects of modified clays on the thermal properties of nanocomposites are analyzed by differential scanning calorimetry and thermogravimetric analyses showing an increase of glass and decomposition temperatures of all nanocomposites respect to homopolymer ones. The best results are obtained in the presence of silylated montmorillonites, clearly the organosilane improves the compatibility between polymer matrix and clay and as effect the properties of nanocomposites.

Polyvinylalcohol/graphite nanocomposites with graphite nanosheets have been prepared by a mechanical method based on grinding of graphite powder, under low energy pure shearing milling, using water or KOH as lubricant. The use of different lubricant concurs to obtain graphite sheets that differently disperse in hydrophilic polymeric matrix. An improvement of water vapor permeability (up to 12%), compared with homopolymer, has been observed.

In this work, particle inception and early growth stages were investigated in an ethylene/air premixed flame by the evolution of the particle size and structure with flame residence time. Particle size distribution was measured by a scanning mobility particle seizer and chemical-physical investigation was carried out by Raman microspectroscopy, UV-visible light absorption and cyclic voltammetry. From early inception of particles, just downstream the flame front, to the formation of primary soot particles, in the post-oxidation flame zone, particles participate in a series of chemical and physical reactions that strongly modify their nanostructure and physicochemical properties, resulting in different optical and electronic characteristics. The results presented in this study show that the evolution from a mono-modal to a bi-modal size distribution is associated to a particle graphitization process consisting of a slight increase of the in plane average size of the polyaromatic units within the particles, La, and on the formation of stacks of polyaromatic planes. These outcomes suggest that in our flame conditions particle coagulation/coalescence has a major role in the initial soot formation, affecting both physical and chemical particle properties. © 2015 The Combustion Institute.

A strategy for the synthesis of new chiral salen type ligands derived from α- d -glucose and α- d -mannose is described. The compounds were obtained by introducing appropriate functions at the C2 and C3 positions of the sugar ring. The efficiency of the complexes in the epoxidation of styrenes was also examined and shown to give good results, for example, cis -β-methylstyrene was functionalised with ee’s of up to 86%.

ZnO nanorods are a good candidate for replacing standard photoanodes, such as TiO2, in perovskite solar cells and in principle superseding the high performances already obtained. This is possible because ZnO nanorods have a fast electron transport rate due to their large surface area. An array of ZnO nanorods is grown by chemical bath deposition starting from Al-doped ZnO (AZO) used both as a seed layer and as an efficient transparent anode in the visible spectral range. In particular, in this work we fabricate methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells using glass/AZO/ZnO nanorods/perovskite/Spiro-OMeTAD/Au as the architecture. The growth of ZnO nanorods has been optimized by varying the precursor concentrations, growth time and solution temperature. All the fabrication process and photovoltaic characterizations have been carried out in ambient air and the devices have not been encapsulated. Power conversion efficiency as high as 7.0% has been obtained with a good stability over 20 d. This is the highest reported value to the best of our knowledge and it is a promising result for the development of perovskite solar cells based on ZnO nanorods and AZO. © 2017 IOP Publishing Ltd.

Hybrid heterojunctions of conjugated polymers and inorganic nanomaterials are a promising combination for obtaining high performance solar cells (SC). In this work we have explored new possible uses of the WS2 nanotubes (NTs) both as the only acceptor material blended with a polymer and in ternary systems mixed with a polymer and quantum dots (QDs). In particular we have spectroscopically investigated binary blends of poly(3-hexylthiophene) (P3HT) and WS2 NTs, P3HT and CdSe QDs, and ternary blends of P3HT, CdSe QDs and WS2 NTs. We report fluorescence quenching effects of the QD signal in the P3HT-CdSe-WS2 system with the increase of NT concentration. Static and time-resolved fluorescence studies reveal efficient resonant energy transfer from the QDs to the NTs upon photoexcitation. The evidence of energetic interaction between WS2 NTs and QDs opens new fields of application of WS2 NTs and holds very promising potential for improving charge transfer phenomena in the active layer of hybrid solar cells. This journal is © the Partner Organisations 2014.

New nitrogen chelates of formula 6-R-C5H3NCHNR′-2 and R′NCHCHNR′ (R = H or Me; R′ = 2,3,4,6-tetra-O-acetyl-β-D-glucopyranose residue) were prepared. The nitrogen donor atom is directly linked to a chiral carbon, i.e. the C1 atom of the sugar ring. The ability of the ligands to induce enantioselective co-ordination of prochiral olefins was assessed by preparing palladium(0) complexes of formula [Pd(N,N-chelate)(olefin)]. Hydrophilic complexes obtained by deprotection of the hydroxy groups of the sugar residue were used for hydrogenating alkenes in water. The course of the reaction is strongly influenced by pH, and homogeneous hydrogenation of the double bond takes place only under basic conditions.

Two red emitters InP/ZnS quantum dots (QDs) (absorption 570 nm/emission 605 nm and absorption 597/emission 624) were inserted at different concentrations in the blue emitting polymer poly(9,9'- dioctylfluorene) (PFO). Nanocomposites were obtained by mixing the QDs as purchased and the polymer dissolved in the appropriate solvent and deposited by spin coating to give homogeneous films. The morphological properties were characterized by scanning electron microscopy (SEM), that showed a good level of dispersion of the QDs within the polymer. The study of the optical and electrooptical properties of the nanocomposites layer inserted in OLED devices (glass/ITO/PEDOT:PSS/PFO-QD/Ca/Al) is reported and compared to pure polymer based device. Photoluminescence and electroluminescence spectra show an energy transfer from the polymer to QDs in presence of the nanocomposites containing InP/ZnS quantum dots that absorb at 570 nm. © 2013 American Scientific Publishers.

In this work, we studied energetic and optical proprieties of a polyester-containing oxadiazole and carbazole units that we will indicate as POC. This polymer is characterized by high photoluminescence activity in the blue region of the visible spectrum, making it suitable for the development of efficient white-emitting organic light emission devices. Moreover, POC polymer has been combined with two red emitters InP/ZnS quantum dots (QDs) to obtain nanocomposites with wide emission spectra. The two types of QDs have different absorption wavelengths: 570 nm [InP/ZnS(570)] and 627 nm [InP/ZnS(627)] and were inserted in the polymer at different concentrations. The optical properties of the nanocomposites have been investigated and compared to the ones of the pure polymer. Both spectral and time resolved fluorescence measurements show an efficient energy transfer from the polymer to QDs, resulting in white-emitting nanocomposites. © Springer Science+Business Media Dordrecht 2013.

A new blue emitter oxadiazole/carbazole copolymer has been synthesized and combined with CdSe/ZnS quantum dots (QDs). Surface passivation of the QDs by ionic liquids was crucial to improve their compatibility with the polymer allowing the deposition of homogeneous nanocomposites films. The nanocomposites have been characterized by thermogravimetric analysis, infrared, UV–visible absorption, and photoluminescence spectroscopy. The emission spectra of nanocomposites show a wide spectrum from blue to orange wavelengths due to the combination of colors emitted by the polymer and QDs, respectively. POLYM. COMPOS., 34:1471–1476, 2013. © 2013 Society of Plastics Engineers

In the present study we investigated a combination of quantum dots with multi-walled carbon nanotubes as a possible future additive to the active layer of polymer solar cells. In this case the quantum dots should serve to enhance the long wavelength response of the solar cell, while the nanotubes enhance the charge carrier collection efficiency by favoring charge carrier separation and enhancement of the lateral conduction of the films. In order to clarify the interplay of the nanoparticles only, we deposited them into a non-conducting and transparent polymethyl-methalacrylate (PMMA) matrix. InP/ZnS quantum dots with an emission peak wavelength of 660 nm have been chosen in this study, because their addition can enhance the long wavelength response of conventional poly(3-hexylthiophene) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) bulk heterostructure polymer solar cells. In our study we kept the quantum dot concentration constant and varied the concentration of the carbon nanotubes (CNTs) in the deposited films. The characterization of the film morphology by scanning electron microscopy (SEM) imaging and of the optical properties by photoluminescence and transmittance revealed a rather complex interplay between nanotubes and quantum dots. In particular we found a strong quenching of the photoluminescence and an inhomogeneous CNT distribution for carbon nanotube concentrations exceeding 1%. The decrease in optical transmittance of the films with increasing CNT concentration is less pronounced, when quantum dots (QDs) are added. The optical transmittance in a wavelength range between 380 nm and 800 nm of the composites could be expressed empirically as a simple second order polynomial function. © 2013 Elsevier B.V. All rights reserved.

We report our results on the effect of incorporation of inorganic fullerene like nanoparticles (IF) and inorganic nanotubes (INT) of WS2 into hybrid LED device structures. To disperse into a uniform fashion, the semiconducting INT/IF WS2 NTs were functionalized with SDS (sodium dodecylsulphate). The IF/INT WS2 nanotubes were used in combination with PEDOT:PSS and P3HT to realize the following LED device structures: ITO/(PEDOT:PSS):(WS2:SDS)/P3HT/LiF-Al; ITO/PEDOT:PSS/P3HT/WS2:SDS/LiF-Al. Morphological, optical and electrochemical analysis were performed to obtain the HOMO and the LUMO energy levels to hypothesize the most efficient device structure. The spectral positions of the electroluminescent bands were found out to be device-dependent and exhibits blue shift when the proposed nanostructure is dip coated on top of P3HT. Electro-optical analysis indicate that the WS2:SDS based P3HT/semiconductor film can improve the charge recombination probability owing to its dual functionality as hole blocking layer and electron injection moiety.

New luminescent polymer nanocomposites were synthesized combining carbazole/oxadiazole copolymer (POC) and CdSe/ZnS quantum dots (QDs) surface passivated by ionic liquids. Ionic liquid ligands improve the photostability of QDs and their compatibility with polymer allowing the deposition of homogeneous nanocomposites films. The nanocomposites were characterized by UV and photoluminescence spectroscopy.

This paper describes a straightforward strategy for the synthesis of new nitrogen chelates by employing the chirality of readily available sugars. Thus, diimino and diamino ligands can be attained easily by using the methyl-4,6- O -benzylidene-2,3-diazo-2,3-dideoxy-α- d -mannopyranoside skeleton. The coordinating ability of one ligand has also been assessed by preparing a square-planar palladium complex [PdCl 2 ( N , N -chelate)].

Palladium mediated hydrolysis of coordinated acetonitrile in the complex [Pd(phen)(MeCN)2](BF4)2, under basic conditions, affords the dinuclear palladium(II) species bis(μ-acetamido-O,N) {bis[(1,10-phenanthroline)palladium(II)]}bis-tetrafluoroborate. X-ray crystallographic analysis of this species (structure a) and of its acetonitrile solvate (structure b) shows that the syn isomer of the complex is formed and that dimers aggregate to form discrete tetrameric units (Pd–Pd intradimer distances 2.875(3) A (a), 2.852(1) A (b) and Pd–Pd* interdimer distances 3.213(3) A (a), 3.079(1) A (b)). The correlation between syn-coordination mode and aggregation of dimers is discussed.

A strategy for the preparation of a supported ‘salen-type’ Mn(III) catalyst derived from d -glucose is described. The compound has been prepared by introducing the ligand functions at positions 2 and 3 of the sugar, which has been subsequently anchored to a CHO-modified Wang resin through formation of a 4,6-O-benzylidene ring. The activity of the catalyst in the asymmetric epoxidation of styrenes has been investigated by using four different oxidants.