Photonic Band Gap Engineering by Varying the Inverse Opal Wall Thickness.

We demonstrate the band gap programming of inverse opals by fabrication of different wall thickness by atomic layer deposition (ALD). The opal templates were synthesized using polystyrene and carbon nanospheres by the vertical deposition method. The structure and properties of the TiO inverse opal samples were investigated using Scanning Electron Microscope (SEM) and Focused Ion Beam Scanning Electron Microscopy (FIB-SEM), Energy Dispersive X-ray analysis (EDX), X-ray Diffraction (XRD) and Finite Difference Time Domain (FDTD) simulations.

NiO Nano- and Microparticles Prepared by Solvothermal Method-Amazing Catalysts for CO Methanation.

Nickel oxide (NiO) is one of the most popular hydrogenation catalysts. In heterogeneous catalysis, nickel oxide is used, for example, as a suitable methanation catalyst in the Fischer-Tropsch reaction not only for CO hydrogenation but also in the modified Fischer-Tropsch reaction with CO. However, CH selectivity and CO conversion strongly depend on NiO micro- (MPs) and nanoparticles' (NPs) shape, size, and surface area.

Synthesis of TiO/AlO Double-Layer Inverse Opal by Thermal and Plasma-Assisted Atomic Layer Deposition for Photocatalytic Applications.

In comparison to conventional nano-infiltration approaches, the atomic layer deposition (ALD) technology exhibits greater potential in the fabrication of inverse opals (IOs) for photocatalysts. In this study, TiO IO and ultra-thin films of AlO on IO were successfully deposited using thermal or plasma-assisted ALD and vertical layer deposition from a polystyrene (PS) opal template. SEM/EDX, XRD, Raman, TG/DTG/DTA-MS, PL spectroscopy, and UV Vis spectroscopy were used for the characterization of the nanocomposites.

Experimental Investigation of Rheological Properties and Thermal Conductivity of SiO-TiO Composite Nanofluids Prepared by Atomic Layer Deposition.

In the current research, surface-modified SiO nanoparticles were used upon immersion in an applied base fluid (ethylene glycol:water = 1:1). The atomic layer deposition method (ALD) was introduced to obtain a thin layer of TiO to cover the surface of SiO particles. After the ALD modification, the TiO content was monitored by energy dispersive X-ray spectroscopy (EDS).

Thermal Conductivity Enhancement of Atomic Layer Deposition Surface-Modified Carbon Nanosphere and Carbon Nanopowder Nanofluids.

In this paper, we present a study on thermal conductivity and viscosity of nanofluids containing novel atomic layer deposition surface-modified carbon nanosphere (ALD-CNS) and carbon nanopowder (ALD-CNP) core-shell nanocomposites. The nanocomposites were produced by atomic layer deposition of amorphous TiO. The nanostructures were characterised by scanning (SEM) and transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, thermogravimetry/differential thermal analysis (TG/DTA) and X-ray powder diffraction (XRD).

Growth and Characterization of Graphene Layers on Different Kinds of Copper Surfaces.

Graphene films were grown by chemical vapor deposition on Cu foil. The obtained samples were characterized by Raman spectroscopy, ellipsometry, X-ray photoelectron spectroscopy and electron back-scatter diffraction. We discuss the time-dependent changes in the samples, estimate the thickness of emerging CuO beneath the graphene and check the orientation-dependent affinity to oxidation of distinct Cu grains, which also governs the manner in which the initial strong Cu-graphene coupling and strain in the graphene lattice is released.

Photocatalytic Crystalline and Amorphous TiO Nanotubes Prepared by Electrospinning and Atomic Layer Deposition.

In this work core/shell composite polymer/TiO nanofibers and from those TiO nanotubes were prepared. First, poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) fibers were synthetized by electrospinning. They were covered with a 100 nm thick amorphous TiO layer by atomic layer deposition at 50 °C.

3D phase diagrams and the thermal stability of two-component Janus nanoparticles: effects of size, average composition and temperature.

Determining binary phase diagrams for nanoparticles proves to be a very difficult task regardless if it is tried either by computer simulations, theoretical considerations or experiments. In this work, using 3D Object Stochastic Kinetic Modelling Framework (3DO-SKMF) computer simulations, we reveal some of the reasons why this is the case. First of all, even the expressions "phase diagram" and "phase composition" are usually not well-defined.

Preparation of TiO/WO/C/N Composite Nanofibers by Electrospinning Using Precursors Soluble in Water and Their Photocatalytic Activity in Visible Light.

Extending the absorption range of TiO nanofibers to visible light is a great improvement of the photocatalytic property of TiO. In this study, TiO/WO/C/N nanofibers were prepared by electrospinning using precursors soluble in water then annealing in argon. Titanium(IV) bis(ammonium lactato)dihydroxide (TiBALDH) and ammonium metatungstate (AMT) were used as the precursor for TiO and WO respectively.

A versatile technique for in situ investigation of the effect of thin film cracking on gas permeation of coated flexible polymers.

In this work, we report the development of a measurement chamber linked with a quadrupole mass spectrometer (QMS) for in situ investigation of the effect of thin film cracking on the gas permeation of coated flexible polymeric substrates. The chamber enables the establishment of a bulged state of the substrate/coating system, which causes the cracking of the coating layer. The increase in the gas permeation rate due to the presence of cracks can be monitored precisely using the QMS without movement or re-clamping of the samples between each measurement step.

Synthesis and Stabilization of Support-Free Mesoporous Gold Nanoparticles.

Porous gold nanoparticles (PGNs) are usually prepared in an immobilized form on a solid substrate, which is not practical in many applications. In this work, a simple method is reported for the preparation and stabilization of mesoporous gold particles of a few hundred nanometers in size in aqueous suspension. Nanoparticles of Ag-Au alloy were fabricated on CaF 2 and Si/SiO 2 substrates by the solid-state dewetting method.

Encoding Information into Polyethylene Glycol Using an Alcohol-Isocyanate "Click" Reaction.

In this article, the capability of encoding information using a homologous series of monodisperse monomethoxypolyethylene glycols (mPEG), with a number of ethylene oxide units ranging from n = 5 to 8, and monodisperse linear aliphatic isocyanates containing a number of CH units from 3 to 7, is demonstrated. The "click" reaction of the two corresponding homologous series yielded 20 different isocyanate end-capped polyethylene glycol derivatives (mPEG-OCONHR) whose sodiated adduct ion's nominal / values spanned from 360 to 548, providing an average ca. 8 / unit for the storage of one-bit information.

Decoration of Vertically Aligned Carbon Nanotubes with Semiconductor Nanoparticles Using Atomic Layer Deposition.

Vertically aligned carbon nanotubes (VACNTs or "CNT forest") were decorated with semiconductor particles (TiO₂ and ZnO) by atomic layer deposition (ALD). Both the structure and morphology of the components were systematically studied using scanning (SEM) and high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and X-ray diffraction (XRD) methods. Characterization results revealed that the decoration was successful in the whole bulk of VACNTs.

Photocatalytic hollow TiO and ZnO nanospheres prepared by atomic layer deposition.

Carbon nanospheres (CNSs) were prepared by hydrothermal synthesis, and coated with TiO and ZnO nanofilms by atomic layer deposition. Subsequently, through burning out the carbon core templates hollow metal oxide nanospheres were obtained. The substrates, the carbon-metal oxide composites and the hollow nanospheres were characterized with TG/DTA-MS, FTIR, Raman, XRD, SEM-EDX, TEM-SAED and their photocatalytic activity was also investigated.

Nanoporous Gold Nanoparticles and Au/AlO Hybrid Nanoparticles with Large Tunability of Plasmonic Properties.

Nanoporous gold nanoparticles (NPG-NPs) with controlled particle size and pore size are fabricated via a combination of solid-state dewetting and a subsequent dealloying process. Because of the combined effects of size and porosity, the NPG-NPs exhibit greater plasmonic tunability and significantly higher local field enhancement as compared to solid NPs. The effects of the nanoscale porosity and pore size on the optical extinction are investigated for the NPG-NPs with different particle sizes experimentally and theoretically.

Relationship between structural changes, hydrogen content and annealing in stacks of ultrathin Si/Ge amorphous layers.

Hydrogenated multilayers (MLs) of a-Si/a-Ge have been analysed to establish the reasons of H release during annealing that has been seen to bring about structural modifications even up to well-detectable surface degradation. Analyses carried out on single layers of a-Si and a-Ge show that H is released from its bond to the host lattice atom and that it escapes from the layer much more efficiently in a-Ge than in a-Si because of the smaller binding energy of the H-Ge bond and probably of a greater weakness of the Ge lattice. This should support the previous hypothesis that the structural degradation of a-Si/a-Ge MLs primary starts with the formation of H bubbles in the Ge layers.

Transient interface sharpening in miscible alloys.

We observed that diffuse interfaces sharpen rather than broaden in completely miscible ideal binary systems. This is shown in situ during heat treatments at gradually increasing temperatures by scattering of synchrotron radiation in coherent Mo/V multilayers containing initially diffuse interfaces. This effect provides a useful tool for the improvement of interfaces and offers a way to fabricate better x-ray or neutron mirrors, microelectronic devices, or multilayers with giant magnetic resistance.