Graphite-type activated carbon from coconut shell: a natural source for eco-friendly non-volatile storage devices.

Carbon from biomass as an active material for supercapacitor electrodes has attracted much interest due to its environmental soundness, abundance, and porous nature. In this context, activated carbon prepared from coconut shells a simple activation process (water or steam as activation agents) was used as an active material in electrodes for eco-friendly supercapacitors. X-ray diffraction (XRD), Raman spectroscopy, conductivity, scanning electron microscopy (SEM), N sorption and thermogravimetry coupled to mass spectrometry (TGA-MS) studies revealed that activated carbon produced by this approach exhibit a graphitic phase, a high surface area, and large pore volume.

Rapid synthesis of ultra-long silver nanowires for high performance transparent electrodes.

By using 1,2-propanediol instead of the classic polyol solvent, ethylene glycol, ultra-long silver nanowires are obtained in only 1 h. These nanowires lead to transparent electrodes with a sheet resistance of 5 Ohms per sq at a transparency of 94%, one of the highest figures of merit for nanowire electrodes ever reported.

Increasing Silver Nanowire Network Stability through Small Molecule Passivation.

Silver nanowire (AgNW) transparent electrodes show promise as an alternative to indium tin oxide (ITO). However, these nanowire electrodes degrade in air, leading to significant resistance increases. We show that passivating the nanowire surfaces with small organic molecules of 11-mercaptoundecanoic acid (MUA) does not affect electrode transparency contrary to typical passivation films, and is inexpensive and simple to deposit.

Probing some organic ukiyo-e Japanese pigments and mixtures using non-invasive and mobile infrared spectroscopies.

Non-invasive identification of organic colourants in paintings still remains a challenging issue, especially in the case of extremely thin layers of paint on printed paper such as Japanese ukiyo-e prints. Because prints are fragile artworks, various non-invasive analytical methods need to be employed. The present work focuses on results obtained by combining fibre optic reflectance spectroscopy in the near-infrared range (FORS NIR) with mid-infrared (MIR) spectroscopy.

Surface bound VEGF mimicking peptide maintains endothelial cell proliferation in the absence of soluble VEGF in vitro.

Continuous glucose monitoring is an efficient method for the management of diabetes and in limiting the complications induced by large fluctuations in glucose levels. For this, intravascular systems may assist in producing more reliable and accurate devices. However, neovascularization is a key factor to be addressed in improving their biocompatibility.

Improved photocatalytic activity in RuO2-ZnO nanoparticulate heterostructures due to inhomogeneous space charge effects.

New 2-6 wt% RuO2-ZnO heterojunction nanocatalysts were synthesized by a straightforward two-step procedure. They were composed of a porous network of aggregated 25 nm wurtzite ZnO nanocrystallites modified with RuO2 and showed enhanced light absorption in the visible region due to surface plasmon resonance. In order to investigate the energetic structure of the photocatalyst XPS core line and valence band spectra of in situ in UHV prepared heterointerfaces were compared to results obtained from the particles.

Nanostructured SnO2-ZnO heterojunction photocatalysts showing enhanced photocatalytic activity for the degradation of organic dyes.

Nanoporous SnO(2)-ZnO heterojunction nanocatalyst was prepared by a straightforward two-step procedure involving, first, the synthesis of nanosized SnO(2) particles by homogeneous precipitation combined with a hydrothermal treatment and, second, the reaction of the as-prepared SnO(2) particles with zinc acetate followed by calcination at 500 °C. The resulting nanocatalysts were characterized by X-ray diffraction (XRD), FTIR, Raman, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analyses, transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectroscopy. The SnO(2)-ZnO photocatalyst was made of a mesoporous network of aggregated wurtzite ZnO and cassiterite SnO(2) nanocrystallites, the size of which was estimated to be 27 and 4.

Quantitative label-free RNA detection using surface-enhanced Raman spectroscopy.

Surface-Enhanced Raman Spectroscopy (SERS) was performed to detect label-free RNA. We defined conditions which make it possible to probe the four bases of RNA, in single strands of polyadenosine (pA), polyuridine (pU), polycytosine (pC) and polyguanosine (pG). We therefore present below a quantitative analysis of mixtures of non-hybridized single strands, based on the deconvolution of the SERS mixture spectrum into the relative contributions of the SERS spectra of each constituent.

Self-assembled titanium-based hybrids with cyclopentadienyl-titanium network bonding.

Unprecedented stable hybrid materials with cyclopentadienyl-titanium bonds have been obtained from the hydrolysis of suitable precursors. Their inorganic network is not fully condensed and they show variable short-range self-organizations, the type of which depends on the shape of the ligands.

Comparative studies of nontoxic and toxic amyloids interacting with membrane models at the air-water interface.

Many in vitro studies have pointed out the interaction between amyloids and membranes, and their potential involvement in amyloid toxicity. In a previous study, we generated a yeast toxic mutant (M8) of the harmless model amyloid protein HET-s((218-289)). In this study, we compared the self-assembling process of the nontoxic wild-type (WT) and toxic (M8) protein at the air-water interface and in interaction with various phospholipid monolayers (DOPE, DOPC, DOPI, DOPS and DOPG).

Remote surface enhanced Raman spectroscopy imaging via a nanostructured optical fiber bundle.

Remote surface enhanced Raman spectroscopy (SERS) imaging of an adsorbed monolayer was demonstrated through a nanostructured array of conical tips inscribed onto the distal face of a 30 cm optical fiber bundle. Despite intense Raman signal from the germanium oxide doped fibers, the Raman signal of an adsorbed monolayer of a reference compound (benzene thiol) was detected in the fingerprint region. This opens up the possibility of local remote imaging through an optical fiber that embeds a SERS active platform.

Raman enhancement of azobenzene monolayers on substrates prepared by Langmuir-Blodgett deposition and electron-beam lithography techniques.

Nanostructured metallic platforms for Raman enhancement were fabricated using Langmuir-Blodgett and electron beam (e-beam) lithography techniques. The gold platforms were inscribed on thin glass slides with the purpose of using them in a transmission geometry experimental setup under a confocal microscope. The plasmon frequency of the gold nanostructures was determined in the visible-near-infrared range for various pattern sizes prepared by Langmuir-Blodgett transfer and e-beam lithography.

Chemical reaction imaging within microfluidic devices using confocal raman spectroscopy: the case of water and deuterium oxide as a model system.

Microfluidic devices face presently a tremendous interest, especially for the development of labs-on-a-chip systems. One of the primary challenges for such applications is the ability to perform local chemical detection and analysis from various species. In this paper, we investigate the use of confocal Raman spectroscopy from both qualitative and quantitative sides, to obtain spatially resolved concentration maps of chemically reactive fluids flowing in different channels networks.

Protection of lithium metal surfaces using chlorosilanes.

In this paper, we present a new approach for protecting metallic lithium surfaces based on a reaction between the thin native layer of lithium hydroxide present on the surface and various chlorosilane derivatives. The chemical composition of the resulting layer and the chemistry involved in layer formation were analyzed by polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDX). Spectroscopy shows the disappearance of surface hydroxide groups and the appearance of silicon and chloride on the lithium surface.

Confocal microscopy imaging of electrochemiluminescence at double band microelectrode assemblies: numerical solution of the inverse optical problem.

A realistic theoretical model describing the outcome of confocal microscopic imaging of electrochemiluminescence (ECL) light emission is derived for a two parallel band microelectrodes assembly operated under steady state. The model takes into account the experimental distortions ensuing from a) the specific finite shape of the sampling volume in confocal microscopy, b) the light arising directly from out-of-focus area but transmitted through the microscope diaphragm or c) transmitted after reflection from the polished platinum band electrodes. The model is based on a detailed optical, physico-mathematical and numerical analysis of the problem at hand, and on simulations of the concentration distribution of the species giving rise to the ECL generation.

On-line laser Raman spectroscopic probing of droplets engineered in microfluidic devices.

Sub-nanolitre droplets engineered in microfluidic devices constitute ideal microreactors to investigate the kinetics of chemical reactions on the millisecond time scale. Up to date, fluorescence detection has been extensively used in chemistry and biology to probe reactants and resultant products within such nanodroplets. However, although fluorescence is a very sensitive technique, it lacks intrinsic specificity as frequently fluorescent labels need to be attached to the species of interest.

Mapping electrochemiluminescence as generated at double-band microelectrodes by confocal microscopy under steady state.

A confocal microspectrometer was used to collect spatially resolved electrochemiluminescence (ECL) spectra from the annihilation reaction between Ru(bpy)3+ and Ru(bpy)3(3+), each species being generated at a platinum band microelectrode and separated by a micrometric insulating gap. The use of a confocal microspectrometer allows in situ photon detection of the ECL reaction with micrometric spatial resolution and observes the concentration distribution of the photon source in the vicinity of the interelectrode gap.

Remote fluorescence imaging of dynamic concentration profiles with micrometer resolution using a coherent optical fiber bundle.

Dynamic concentration profiles within the diffusion layer of an electrode were imaged in situ using fluorescence detection through a multichannel imaging fiber. In this work, a coherent optical fiber bundle is positioned orthogonal to the surface of an electrode and is used to report spatial and temporal micrometric changes in the fluorescence intensity of an initial fluorescent species. The fluorescence signal is directly related to the local concentration of a redox fluorescent reagent, which is electrochemically modulated by the electrode.

Electrochemical modulation of remote fluorescence imaging at an ordered opto-electrochemical nanoaperture array.

An array of nanometer-sized apertures capable of electrochemically modulating the fluorescence of a model analyte is presented. The device, which combines near-field optical methods and ultramicroelectrode properties in an array format, is based on an etched coherent optical fiber bundle. Indeed, the fabrication steps produced an ordered array where each optical nanoaperture is surrounded by a ring-shaped gold nanoelectrode.