Photo-assisted epitaxial growth from nanoparticles to enhance multi-materialization for advanced surface functionalization.

To meet the requirements of freeform objects, a wide range of highly designable resin-based materials has been created, highlighting the need for low-temperature ceramic deposition methods for surface functionalization. Photo-assisted chemical solution deposition (PCSD), an efficient technique for low-temperature ceramic growth, is used to fabricate thin films photochemical and photothermal effects. The hybrid-solution-incorporated PCSD (HS-PCSD), in which a hybrid-solution comprising metal-organic compounds and nanoparticles is used in PCSD, has attracted considerable interest as it enables deposition at reduced temperatures and accelerated rates.

Key Sputtering Parameters for Precursor InO Films to Achieve High Carrier Mobility.

Owing to their extremely high carrier mobility (μ) of >100 cm/(V s) and suitable low carrier concentrations, transparent conducting films of solid-phase crystallized H-doped InO (spc-IO:H) exhibit high conductivity with high optical transparency over a broad frequency range. These properties can be attributed to solid-phase crystallization of the amorphous precursor film. Therefore, the development of high-quality spc-IO:H films requires the deposition conditions of the precursor films to be optimized.

Single-atomic-site platinum steers photogenerated charge carrier lifetime of hematite nanoflakes for photoelectrochemical water splitting.

Although much effort has been devoted to improving photoelectrochemical water splitting of hematite (α-FeO) due to its high theoretical solar-to-hydrogen conversion efficiency of 15.5%, the low applied bias photon-to-current efficiency remains a huge challenge for practical applications. Herein, we introduce single platinum atom sites coordination with oxygen atom (Pt-O/Pt-O-Fe) sites into single crystalline α-FeO nanoflakes photoanodes (SAs Pt:FeO-Ov).

Printing Formation of Flexible (001)-Oriented PZT Films on Plastic Substrates.

High-quality, uniaxially oriented, and flexible PbZrTiO (PZT) films were fabricated on flexible RbLaNbO/BaTiO (RLNO/BTO)-coated polyimide (PI) substrates. All layers were fabricated by a photo-assisted chemical solution deposition (PCSD) process using KrF laser irradiation for photocrystallization of the printed precursors. The Dion-Jacobson perovskite RLNO thin films on flexible PI sheets were employed as seed layers for the uniaxially oriented growth of PZT films.

Dynamic semiconductor-electrolyte interface for sustainable solar water splitting over 600 hours under neutral conditions.

Photoelectrochemical (PEC) water splitting that functions in pH-neutral electrolyte attracts increasing attention to energy demand sustainability. Here, we propose a strategy to in situ form a NiB layer by tuning the composition of the neutral electrolyte with the additions of nickel and borate species, which improves the PEC performance of the BiVO photoanode. The NiB/BiVO exhibits a photocurrent density of 6.

Flexible Ceramic Film Sensors for Free-Form Devices.

Recent technological innovations, such as material printing techniques and surface functionalization, have significantly accelerated the development of new free-form sensors for next-generation flexible, wearable, and three-dimensional electronic devices. Ceramic film sensors, in particular, are in high demand for the production of reliable flexible devices. Various ceramic films can now be formed on plastic substrates through the development of low temperature fabrication processes for ceramic films, such as photocrystallization and transferring methods.

Solar-to-Pharmaceutical Raw Material Production: Photoelectrochemical Naphthoquinone Formation Using Stabilized BiVO Photoanodes in Acid Media.

In the quest for efficient use of solar energy to produce high-value-added chemicals, we first achieved the photoelectrochemical (PEC) diketonization of naphthalene, using a BiVO/WO photoanode, to obtain naphthoquinone, an important pharmaceutical raw material with excellent efficiency by solar energy conversion. In the electrochemical (EC) reaction using F-doped SnO (FTO) substrates and a 0.5 M HSO HO-acetone (60 vol %) mixed solution containing 5 mM naphthalene, we produced a small amount of naphthoquinone evolution in the dark.

Photo-driven Oxygen Vacancies Extends Charge Carrier Lifetime for Efficient Solar Water Splitting.

A photocharge/discharge strategy is proposed to initiate the WO photoelectrode and suppress the main charge recombination, which remarkably improves the photoelectrochemical (PEC) performance. The photocharged WO surrounded by a 8-10 nm overlayer and oxygen vacancies could be operated more than 25 cycles with 50 h durability without significant decay on PEC activity. A photocharged WO /CuO photoanode exhibits an outstanding photocurrent of 3.

Acid-Resistant BiVO Photoanodes: Insolubility Control by Solvents and Weak W Diffusion in the Lattice.

We have revealed for the first time that BiVO photoanodes can be used even in strong acid media by mixing organic solvents into the electrolyte and depositing multilayers with a WO bottom layer. In general, the BiVO photoanodes are photocorrosive, especially in acid solutions. However, this shortcoming has been overcome using a combination of the two aforementioned modifications.

Ultrathin Highly Flexible Featherweight Ceramic Temperature Sensor Arrays.

We fabricated highly flexible Sr- and Ni-doped perovskite SmMnO thermistor film sensor arrays on an ultrathin (5 μm thick) and lightweight (21 mg) polyimide sheet for healthcare monitoring devices. The Ag nanowire and nanoparticle-impregnated carbon microcone array, which was prepared by precisely controlled surface laser carbonization of polyimide, showed sufficiently low resistance as a bottom electrode and good stability against sharp bending angles. The dot-shaped (diameter: 900 μm) perovskite thermistor film with a thickness of 900 nm was crystallized by pulsed ultraviolet laser irradiation of a precursor film printed with perovskite nanoparticle dispersion ink, and the film functioned well as the thermistor with a thermistor constant of 2820 K.

Flexible and Epitaxial Metal Oxide Thin Film Growth by Photoreaction Processing for Electrical and Optical Applications.

This review summarizes the use of photoreactions that replace conventional heating processes for growing oxide thin films from chemical solutions. In particular, this review outlines key variables in photoreactions that affect epitaxial and polycrystalline thin film growth, including precursor materials, laser wavelength, laser fluence, and carbon. In addition, the features of the photoreaction process that can be controlled at a low temperature by oxygen non-stoichiometry are examined.

Improvement of the Properties of Direct-Current Magnetron-Sputtered Al-Doped ZnO Polycrystalline Films Containing Retained Ar Atoms Using 10-nm-Thick Buffer Layers.

The use of a 10-nm-thick buffer layer enabled tailoring of the characteristics, such as film deposition and structural and electrical properties, of magnetron-sputtered Al-doped ZnO (AZO) films containing unintentionally retained Ar atoms. The AZO films were deposited on glass substrates coated with the buffer layer via direct-current magnetron sputtering using Ar gas, a substrate temperature of 200 °C, and sintered AZO targets with an AlO content of 2.0 wt %.

Plant Habitat-Conscious White Light Emission of Dy(3+) in Whitlockite-like Phosphates: Reduced Photosynthesis and Inhibition of Bloom Impediment.

It has been pointed out that agricultural crops and other natural plants may be damaged by outdoor lighting systems. Therefore, lighting that does not affect plant growth is needed. To address this problem, we have prepared a new whitlockite-like phosphate Dy-phosphor Ca8MgY1-x-yLaxDyy(PO4)7, which exhibits a yellow-white Dy(3+) luminescence that has a maximum internal quantum efficiency of 65.

"Black" TiO2 Nanotubes Formed by High-Energy Proton Implantation Show Noble-Metal-co-Catalyst Free Photocatalytic H2-Evolution.

We apply high-energy proton ion-implantation to modify TiO2 nanotubes selectively at their tops. In the proton-implanted region, we observe the creation of intrinsic cocatalytic centers for photocatalytic H2-evolution. We find proton implantation to induce specific defects and a characteristic modification of the electronic properties not only in nanotubes but also on anatase single crystal (001) surfaces.

The significant effect of heterojunction quality on photoelectrochemical water splitting in bilayer photoelectrodes: Rb(x)WO3 thin films on RbLaNb2O7 layers.

We have prepared nearly perfect hexagonal m-plane-oriented RbxWO3 films on (010)-oriented RbLaNb2O7 layers. The prepared bilayer films showed Rb diffusion from the RbLaNb2O7 seed layers, and we obtained uniaxially oriented RbxWO3/Rb1-yLaNb2O7 photoanodes. The RbxWO3/Rb1-yLaNb2O7 bilayer photoanodes exhibited enhanced photoelectrochemical water splitting compared with the RbxWO3 and RbLaNb2O7 monolayer photoanodes.

Hydrogenated anatase: strong photocatalytic dihydrogen evolution without the use of a co-catalyst.

The high-pressure hydrogenation of commercially available anatase or anatase/rutile TiO2 powder can create a photocatalyst for H2 evolution that is highly effective and stable without the need for any additional co-catalyst. This activation effect cannot be observed for rutile; however, for anatase/rutile mixtures, a strong synergistic effect can be found (similar to results commonly observed for noble-metal-decorated TiO2). EPR and PL measurements indicated the intrinsic co-catalytic activation of anatase TiO2 to be due to specific defect centers formed during hydrogenation.

UV-assisted nucleation and growth of oxide films from chemical solutions.

The fabrication of thin oxide films at low temperatures using simple processes has been a significant challenge associated with expanding the potential applications of these materials. Recent developments have demonstrated that the photo-assisted chemical solution deposition (PACSD) process offers a promising means of solving these difficulties, allowing high volume, on-demand production of variable sample sizes using an advantageous wet process. A better understanding of the crystal growth phenomena associated with this process, however, is required to enable various oxide thin films to be prepared using this new concept.

A universal value of effective annealing time for rapid oxide nucleation and growth under pulsed ultraviolet laser irradiation.

The effective annealing times (t(eff)) for nucleating various oxides from an amorphous matrix under nanosecond pulsed laser irradiation have been determined. The oxides, which had perovskite, bixbyite, anatase, and pyrochlore structures, showed similar t(eff) values for crystal nucleation of around 60 ns. This indicates that the effective annealing time is a good universal value for evaluating pulsed laser-induced oxide nucleation.

Direct fabrication of metavanadate phosphor films on organic substrates for white-light-emitting devices.

White-light-emitting materials have attracted considerable attention because of their applications, such as large-surface emitting devices. Inorganic phosphor films are expected to be applied to these devices because of good chemical stability; however, a substantial reduction of fabrication temperature is required for future industrial uses such as lighting materials fabricated onto flexible organic substrates. Here we show the optical properties of white-light-emitting metavanadate phosphors, AVO3 (A: K, Rb and Cs), and we report a new direct fabrication process for RbVO3 films onto flexible polyethylene terephthalate (PET) substrates by means of a vacuum ultraviolet irradiation using an excimer lamp.

Differences in temporal frequency tuning between the two binocular mechanisms for seeing motion in depth.

There are two types of binocular cues available for perception of motion in depth. One is the binocular disparity change in time and the other is the velocity difference between the left and the right retinal images (inter-ocular velocity differences). We measured the luminance contrast threshold for seeing motion in depth while isolating either of the cues at various temporal modulations of velocity in the stimulus.