Defect-Mediated Crystallization of the Particulate TiO Photocatalyst Grown by Atomic Layer Deposition.

Nanopowders or films of pure and mixed oxides in nanoparticulate form have gained specific interest due to their applicability in functionalizing high-surface-area substrates. Among various other applications, our presented work primarily focuses on the behavior of TiO as a photocatalyst deposited by atomic layer deposition (ALD) on a quartz particle. The photocatalytic activity of TiO on quartz particles grown by ALD was studied in terms of ALD growth temperature and post-treatment heating rate.

Influence of the photodeposition sequence on the photocatalytic activity of plasmonic Ag-Au/TiO nanocomposites.

Bimetallic Ag-Au/TiO nanocomposites were synthesized by sequential photodeposition in order to investigate the effect of surface plasmon resonance (SPR) properties on photocatalytic activity for solar water splitting and methylene blue (MB) degradation. The photodeposition times were optimized for monometallic Ag/TiO and Au/TiO nanocomposites to yield maximum SPR absorption in the visible range. It was found that the photocatalytic activity of bimetallic Ag-Au/TiO nanocomposites outperformed monometallic nanocomposites only when Au was photodeposited first on TiO, which was attributed to Au-core-Ag-shell nanoparticle morphology.

Interface Engineering of TiO Photoelectrode Coatings Grown by Atomic Layer Deposition on Silicon.

Titanium dioxide (TiO) can protect photoelectrochemical (PEC) devices from corrosion, but the fabrication of high-quality TiO coatings providing long-term stability has remained challenging. Here, we compare the influence of Si wafer cleaning and postdeposition annealing temperature on the performance of TiO/n-Si photoanodes grown by atomic layer deposition (ALD) using tetrakis(dimethylamido)titanium (TDMAT) and HO as precursors at a growth temperature of 100 °C. We show that removal of native Si oxide before ALD does not improve the TiO coating performance under alkaline PEC water splitting conditions if excessive postdeposition annealing is needed to induce crystallization.

Performance and characterization of the FinEstBeAMS beamline at the MAX IV Laboratory.

FinEstBeAMS (Finnish-Estonian Beamline for Atmospheric and Materials Sciences) is a multidisciplinary beamline constructed at the 1.5 GeV storage ring of the MAX IV synchrotron facility in Lund, Sweden. The beamline covers an extremely wide photon energy range, 4.

Manganese Doping Promotes the Synthesis of Bismuth-based Perovskite Nanocrystals While Tuning Their Band Structures.

The doping of halide perovskite nanocrystals (NCs) with manganese cations (Mn ) has recently enabled enhanced stability, novel optical properties, and modulated charge carrier dynamics of the NCs host. However, the influence of Mn doping on the synthetic routes and the band structures of the host has not yet been elucidated. Herein, it is demonstrated that Mn doping promotes a facile, safe, and low-hazard path toward the synthesis of ternary Cs Bi I NCs by effectively inhibiting the impurity phase (i.

Gas-phase endstation of electron, ion and coincidence spectroscopies for diluted samples at the FinEstBeAMS beamline of the MAX IV 1.5 GeV storage ring.

Since spring 2019 an experimental setup consisting of an electron spectrometer and an ion time-of-flight mass spectrometer for diluted samples has been available for users at the FinEstBeAMS beamline of the MAX IV Laboratory in Lund, Sweden. The setup enables users to study the interaction of atoms, molecules, (molecular) microclusters and nanoparticles with short-wavelength (vacuum ultraviolet and X-ray) synchrotron radiation and to follow the electron and nuclear dynamics induced by this interaction. Test measurements of N and thiophene (CHS) molecules have demonstrated that the setup can be used for many-particle coincidence spectroscopy.

GaAs surface passivation for InAs/GaAs quantum dot based nanophotonic devices.

Several passivation techniques are developed and compared in terms of their ability to preserve the optical properties of close-to-surface InAs/GaAs quantum dots (QDs). In particular, the influence of N-passivation by hydrazine chemical treatment, N-passivation by hydrazine followed by atomic layer deposition (ALD) of AlO and use of AlN deposited by plasma-enhanced ALD are reported. The effectiveness of the passivation is benchmarked by measuring the emission linewidths and decay rates of photo-carriers for the near-surface QDs.

B-Site Co-Alloying with Germanium Improves the Efficiency and Stability of All-Inorganic Tin-Based Perovskite Nanocrystal Solar Cells.

Colloidal lead-free perovskite nanocrystals have recently received extensive attention because of their facile synthesis, the outstanding size-tunable optoelectronic properties, and less or no toxicity in their commercial applications. Tin (Sn) has so far led to the most efficient lead-free solar cells, yet showing highly unstable characteristics in ambient conditions. Here, we propose the synthesis of all-inorganic mixture Sn-Ge perovskite nanocrystals, demonstrating the role of Ge in stabilizing Sn cation while enhancing the optical and photophysical properties.

Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO for Photonic Applications.

Titanium dioxide (TiO) thin films are widely employed for photocatalytic and photovoltaic applications where the long lifetime of charge carriers is a paramount requirement for the device efficiency. To ensure the long lifetime, a high temperature treatment is used which restricts the applicability of TiO in devices incorporating organic or polymer components. In this study, we exploited low temperature (100-150 °C) atomic layer deposition (ALD) of 30 nm TiO thin films from tetrakis(dimethylamido)titanium.

Large-scale efficient water harvesting using bioinspired micro-patterned copper oxide nanoneedle surfaces and guided droplet transport.

As the Earth's atmosphere contains an abundant amount of water as vapors, a device which can capture a fraction of this water could be a cost-effective and practical way of solving the water crisis. There are many biological surfaces found in nature which display unique wettability due to the presence of hierarchical micro-nanostructures and play a major role in water deposition. Inspired by these biological microstructures, we present a large scale, facile and cost-effective method to fabricate water-harvesting functional surfaces consisting of high-density copper oxide nanoneedles.

Diversity of TiO: Controlling the Molecular and Electronic Structure of Atomic-Layer-Deposited Black TiO.

Visually black, electrically leaky, amorphous titania (am-TiO) thin films were grown by atomic layer deposition (ALD) for photocatalytic applications. Broad spectral absorbance in the visible range and exceptional conductivity are attributed to trapped Ti in the film. Oxidation of Ti upon heat treatment leads to a drop in conductivity, a color change from black to white, and crystallization of am-TiO.

Improved Stability of Atomic Layer Deposited Amorphous TiO Photoelectrode Coatings by Thermally Induced Oxygen Defects.

Amorphous titanium dioxide (a-TiO) combined with an electrocatalyst has shown to be a promising coating for stabilizing traditional semiconductor materials used in artificial photosynthesis for efficient photoelectrochemical solar-to-fuel energy conversion. In this study we report a detailed analysis of two methods of modifying an undoped thin film of atomic layer deposited (ALD) a-TiO without an electrocatalyst to affect its performance in water splitting reaction as a protective photoelectrode coating. The methods are high-temperature annealing in ultrahigh vacuum and atomic hydrogen exposure.

Fabrication of ultrathin multilayered superomniphobic nanocoatings by liquid flame spray, atomic layer deposition, and silanization.

Superomniphobic, i.e. liquid-repellent, surfaces have been an interesting area of research during recent years due to their various potential applications.

Building Up Colors: Multilayered Arrays of Peryleneimides on Flat Surfaces and Mesoporous Layers.

Novel monoisomeric perylene imide derivatives with terpyridinyl and pyrrolidinyl substituents were synthesized and deposited onto solid substrates, such as a thin film of Al O and mesoporous TiO nanoparticle layer, by using a simple dip-by-dip method. Arrays of up to 33 layers were built on Al O . In the case of mesoporous TiO , the interstitial volume between the particles was filled up with dye assemblies.

Tailored Fabrication of Transferable and Hollow Weblike Titanium Dioxide Structures.

The preparation of weblike titanium dioxide thin films by atomic layer deposition on cellulose biotemplates is reported. The method produces a TiO web, which is flexible and transferable from the deposition substrate to that of the end application. Removal of the cellulose template by calcination converts the amorphous titania to crystalline anatase and gives the structure a hollow morphology.

Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol overlayers and avidin-biotin technology.

A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions.

Color Bricks: Building Highly Organized and Strongly Absorbing Multicomponent Arrays of Terpyridyl Perylenes on Metal Oxide Surfaces.

Terpyridine-substituted perylenes containing cyclic anhydrides in the peri position were synthesized. The anhydride group served as an anchor for assembly of the terpyridyl-crowned chromophores as monomolecular layers on metal oxide surfaces. Further coordination with Zn(2+) ions allowed for layer-by-layer formation of supramolecular assemblies of perylene imides on the solid substrates.

Ormocomp-modified glass increases collagen binding and promotes the adherence and maturation of human embryonic stem cell-derived retinal pigment epithelial cells.

In in vitro live-cell imaging, it would be beneficial to grow and assess human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells on thin, transparent, rigid surfaces such as cover glasses. In this study, we assessed how the silanization of glass with 3-aminopropyltriethoxysilane (APTES), 3-(trimethoxysilyl)propyl methacrylate (MAPTMS), or polymer-ceramic material Ormocomp affects the surface properties, protein binding, and maturation of hESC-RPE cells. The surface properties were studied by contact angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and a protein binding assay.

Biofunctional hybrid materials: bimolecular organosilane monolayers on FeCr alloys.

Hybrid organic-inorganic interfaces are the key to functionalization of stainless steel (SS). We present a solution-based deposition method for fabricating uniform bimolecular organosilane monolayers on SS and show that their properties and functionalities can be further developed through site-specific biotinylation. We correlate molecular properties of the interface with its reactivity via surface sensitive synchrotron radiation mediated high-resolution photoelectron spectroscopy (HR-PES) and chemical derivatization (CD), and we demonstrate specific bonding of streptavidin proteins to the hybrid interface.