Easy-handling minimum mass laser target scaffold based on sub-millimeter air bubble -An example of laser plasma extreme ultraviolet generation.

Low density materials can control plasma properties of laser absorption, which can enhance quantum beam generation. The recent practical extreme ultraviolet light (EUV) is the first industrial example of laser plasma source with low density targets. Here we propose an easy-handling target source based on a hollow sub-millimeter microcapsule fabricated from polyelectrolyte cationic and anionic surfactant on air bubbles. The lightweight microcapsules acted as a scaffold for surface coating by tin (IV) oxide nanoparticles (22-48%), and then dried. As a proof of concept study, the microcapsules were ablated with a Nd:YAG laser (7.1 × 1010 W/cm2, 1 ns) to generate 13.5 nm EUV relatively directed to laser incidence. The laser conversion efficiency (CE) at 13.5 nm 2% bandwidth from the tin-coated microcapsule (0.8%) was competitive compared with bulk tin (1%). We propose that microcapsule aggregates could be utilized as a potential small scale/compact EUV source, and future quantum beam sources by changing the coating to other elements.

High performance photoanodic catalyst prepared from an active organic photovoltaic cell - high potential gain from visible light.

Photoelectrochemical oxidation of thiols was enhanced with a threshold potential of -0.35 V vs. Ag/AgCl by the use of a ZnPc/PCBM:P3HT/ZnO electode, which was prepared by removing the PEDOT:PSS/Au electrode of an inverted OPV device and coating it with ZnPc. A co-photocatalysis property of ZnPc was observed in the photoelectrochemistry and scanning Kelvin probe microscopy.

Gallium-tin alloys as a low melting point liquid metal for repetition-pulse-laser-induced high energy density state toward compact pulse EUV sources.

Here, we show the easy-handling of a liquid gallium-tin alloy (Ga : Sn) as a laser target source for 13.5 nm light generation. The alloys have ∼30 °C freezing points according to a differential scanning calorimetry cooling process. A Nd:YAG laser (1064 nm, 1 ns, 7.1 × 1010 W cm-2) ablated the alloys, obtaining a similar extreme ultraviolet emission intensity to Sn despite a small quantity of Sn. Finally, we demonstrate a liquid metal alloy jet and droplets using a plastic nozzle for high-repetition target supply.

Electrochemically Synthesized Tin/Lithium Alloy To Convert Laser Light to Extreme Ultraviolet Light.

This paper describes lithium-tin alloys as a novel target material to enhance the efficiency of 13.5 nm extreme ultraviolet (EUV) light from generated laser-produced plasmas. Both lithium and tin exhibit EUV emission with the same peak at 13.5 nm. We show that lithium-tin (LiSn) alloys exhibit emission also at 13.5 nm and a mixture of tin and lithium emission by illuminating Nd:YAG laser (1 ns, 2.5 × 1010, 7.1 × 1010 W/cm2). The emission spectra and emission angular distribution by using phosphor imaging plates were analyzed to obtain the conversion efficiency from laser light to 13.5 nm light. The Li-Sn alloys were slightly higher than planar tin and between tin and lithium. It would be due to the suppression of self-absorption of 13.5 nm light by the tin plasma.

High-space resolution imaging plate analysis of extreme ultraviolet (EUV) light from tin laser-produced plasmas.

With the advent of high volume manufacturing capabilities by extreme ultraviolet lithography, constant improvements in light source design and cost-efficiency are required. Currently, light intensity and conversion efficiency (CE) measurments are obtained by charged couple devices, faraday cups etc, but also phoshpor imaging plates (IPs) (BaFBr:Eu). IPs are sensitive to light and high-energy species, which is ideal for studying extreme ultraviolet (EUV) light from laser produced plasmas (LPPs). In this work, we used IPs to observe a large angular distribution (10°-90°). We ablated a tin target by high-energy lasers (1064 nm Nd:YAG, 1010 and 1011 W/cm2) to generate the EUV light. The europium ions in the IP were trapped in a higher energy state from exposure to EUV light and high-energy species. The light intensity was angular dependent; therefore excitation of the IP depends on the angle, and so highly informative about the LPP. We obtained high-space resolution (345 µm, 0.2°) angular distribution and grazing spectrometer (5-20 nm grate) data simultaneously at different target to IP distances (103 mm and 200 mm). Two laser systems and IP types (BAS-TR and BAS-SR) were also compared. The cosine fitting values from the IP data were used to calculate the CE to be 1.6% (SD ± 0.2) at 13.5 nm 2% bandwidth. Finally, a practical assessment of IPs and a damage issue are disclosed.

A water splitting system using an organo-photocathode and titanium dioxide photoanode capable of bias-free H2 and O2 evolution.

This study examined a water-splitting system comprising a TiO2 photoanode and an organo-photocathode consisting of a p-n bilayer. Stoichiometric decomposition of water into H2 and O2 successfully occurred at bias voltages lower than the theoretical value (i.e. 1.23 V). Compared to the conventional TiO2 and Pt systems, the proposed water-splitting system demonstrated water splitting without any externally applied bias.

Generation Dependent Ultrafast Charge Separation and Recombination in a Pyrene-Viologen Family of Dendrons.

The ability of a dendritic network to intercept electrons and extend the lifetime of a short-lived photoinduced charge separated (CS) state was investigated in a homologous family of methyl viologen (MV(2+)) dendrons spanning four generations, G0 through G3. The CS state in the parent pyrene-methylene-viologen G0 system with a single acceptor exhibits an extremely short lifetime of τ = 0.72 ps. The expansion of the viologen network introduces slower components to the recombination kinetics by allowing the injected electron to migrate further away from the donor. The long-lived fraction of the population increases monotonically in the order G3 > G2 > G1 > G0, while the respective recombination rates decrease. In the highest generation of the dendron ∼14% of the CS state population experiences a 10-fold or greater lifetime extension. Long range tunneling across multiple viologen units and sequential site-to-site hopping both contribute to the overall effect. The large excess energy deposited in the apical viologen upon charge separation and the presence of an extended network of low lying π-orbitals likely facilitate shuttling the electron further down the dendron.

Conical Gradient Junctions of Dendritic Viologen Arrays on Electrodes.

The three-dimensional construction of arrays of functional molecules on an electrode surface, such as organic semiconductors and redox-active molecules, is a considerable challenge in the fabrication of sophisticated junctions for molecular devices. In particular, well-defined organic layers with precise molecular gradients are anticipated to function as novel metal/organic interfaces with specific electrical properties, such as a space charge layer at the metal/semiconductor interface. Here, we report a strategy for the construction of a three-dimensional molecular array with an electrical connection to a metal electrode by exploiting dendritic molecular architecture. Newly designed dendritic molecules consisting of viologens (1,1'-disubstituted-4,4'-bipyridilium salts) as the framework and mercapto groups as anchor units form unique self-assembled monolayers (SAMs) on a gold surface reflecting the molecular design. The dendritic molecules exhibit a conical shape and closely pack to form cone arrays on the substrate, whereas, in solution, they expand into more flexible conformations. Differences in the introduction position of the anchor units in the dendritic structure result in apical- and basal-type cone arrays in which the spatial concentration of the viologen units can be precisely configured in the cones. The concentration in apical-type SAMs increases away from the substrate, whereas the opposite is true in basal-type SAMs.

Spirulina-templated metal microcoils with controlled helical structures for THz electromagnetic responses.

Microstructures in nature are ultrafine and ordered in biological roles, which have attracted material scientists. Spirulina forms three-dimensional helical microstructure, one of remarkable features in nature beyond our current processing technology such as lithography in terms of mass-productivity and structural multiplicity. Spirulina varies its diameter, helical pitch, and/or length against growing environment. This unique helix is suggestive of a tiny electromagnetic coil, if composed of electro-conductive metal, which brought us main concept of this work. Here, we describe the biotemplating process onto Spirulina surface to fabricate metal microcoils. Structural parameters of the microcoil can be controlled by the cultivation conditions of Spirulina template and also purely one-handed microcoil can be fabricated. A microcoil dispersion sheet exhibited optically active response attributed to structural resonance in terahertz-wave region.

Decomposition of hydrazine by an organic fullerene-phthalocyanine p-n bilayer photocatalysis system over the entire visible-light region.

An organic p-n bilayer photocatalysis system successfully induced the oxidative decomposition of hydrazine (N2H4) into N2 and simultaneously yielded H2 from H(+). This demonstrates the first instance of the stoichiometric decomposition of N2H4 under visible-light irradiation.

Enhanced photoanodic output at an organic p/n bilayer in the water phase by means of the formation of whiskered phthalocyanine.

The photoelectrode characteristics of an organic p/n bilayer in the water phase were studied with respect to film; 3,4,9,10-perylenetetracarboxylic-bisbenzimidazole (PTCBI, an n-type semiconductor) was used in combination with 29H,31H-phthalocyanine (H2Pc, a p-type semiconductor). When H2Pc was vapor-deposited on top of the PTCBI layer on a heated substrate (cf. degree of pressure, ca. 5.0 × 10⁻4 Pa; temperature at the substrate, 120°C), a transmission electron microscopic image showed an enhanced contact area of the p/n interface in comparison with that prepared at r.t., due to the formation of a whisker H2Pc. The PTCBI/H2Pc bilayer can work as a photoanode along with photophysical events in its interior. The rate-limiting charge transfer at the H2Pc/water interface was kinetically analyzed assuming the Langmuir adsorption equilibrium at that interface. Kinetic analysis demonstrated that the increased contact area can successfully lead to efficient photoinduced carrier generation; particularly, when a thick whisker of H2Pc was formed, the magnitude of the oxidation kinetics at the H2Pc/water interface was approximately 2.5 times higher than that without thermal treatment.

Photoelectrode characteristics of partially hydrolyzed aluminum phthalocyanine chloride/fullerene C60 composite nanoparticles working in a water phase.

Photoelectrochemical measurements were used to study the photoelectrode characteristics of composite nanoparticles composed of fullerene C60 and partially hydrolyzed aluminum phthalocyanine chloride (AlPc). In cyclic voltammetry measurements, the electrodes coated with the composite nanoparticles were found to have photoanodic [electron donor: 2-mercaptoethanol (ME)] and photocathodic (electron acceptor: O2) characteristics similar to those of the vapor-deposited p/n junction electrode. Their photoanodic features were further investigated with respect to the transient photocurrent response to light irradiation and the dependence on ME concentration (under potentiostatic conditions), from which it was noted that there was a decrease in the initial spiky photocathodic current and saturation of the steady-state photoanodic current at a higher ME concentration. Thus, the reaction kinetics was probably dominated by charge transport process. Moreover, external and internal quantum efficiency spectrum measurements indicated that the composite nanoparticles responded to the full spectrum of visible light ( < 880 nm) for both the photoanodic and photocathodic current. The present research will assist comprehension of photocatalytic behavior of the composite nanoparticles.

Photoelectrochemical and photocatalytic properties of biphasic organic p- and n-type semiconductor nanoparticles fabricated by a reprecipitation process.

The visible-light-responsive photoelectrochemical and photocatalytic properties of nanoparticles of C(60), partially hydrolyzed aluminum phthalocyanine chloride (denoted as AlPc), and a composite of the two are reported. The three types of nanoparticles were obtained through a reprecipitation method from N-methyl-2-pyrrolidone solutions of C(60), aluminum phthalocyanine chloride (AlPcCl), and their mixture, respectively. The nanoparticle composite's ultraviolet-visible absorption, diffuse-reflectance and Fourier transform IR spectra, X-ray diffraction pattern, and scanning electron microscopy image are all similar to the sum of those of the C(60) and AlPc particles, respectively. The nano-ordered composite exhibits p/n junctionlike photoelectrochemical characteristics, which were investigated in comparison with those of vapor-deposited C(60) (n-type), AlPcCl (p-type), C(60)/AlPcCl (n/p), and AlPcCl/C(60) (p/n) electrodes. The nanoparticle composite further shows photocatalytic activity for the decomposition of trimethylamine to carbon dioxide in a suspension system.

Enhanced catalytic activity of gold nanoparticles doped in a mesoporous organic gel based on polymeric phloroglucinol carboxylic acid-formaldehyde.

Gold nanoparticles were supported by a phloroglucinolcarboxylic acid-formaldehyde (PF) gel, a new organic gel with a 30 nm spheroid-like structure. The surface area of the PF gel with gold nanoparticles was 550 m(2)/g. Gold nanoparticles supported on a PF gel exhibited catalytic activity in the reduction of 4-nitrophenol with a reaction rate constant of 7.4 x 10(-3) s(-1), which is high in the reported heterogeneous reaction system. The adsorption behavior of 4-nitrophenol into the gel support was observed by ultraviolet-visible absorption spectroscopy. Gold nanoparticles in the PF network were characterized by scanning electron microscopy, atomic force microscopy, and transmission electron microscopy observation. The high reduction rate would be attributed to the extraction and diffusion of the reactant through the pores of a PF gel support to encounter the highly dispersed gold nanoparticles on the surface and inside the material.

Dry tin dioxide hollow microshells and extreme ultraviolet radiation induced by CO2 laser illumination.

Low-density tin dioxide (SnO2) is required for radiating monochromatic extreme ultraviolet (EUV) light with low debris and high conversion efficiency from a laser. In this paper, tin dioxide nanoparticle hollow microcapsules were successfully fabricated by a layer-by-layer template technique. The obtained capsules have a rougher surface (30 nm in rms) compared to the freshly prepared polyelectrolyte capsules. Based on the X-ray diffraction (XRD) results, the tin dioxide nanoparticles well maintained their size after they were assembled on the capsules' surfaces. In order to remove the polymer template, a heat treatment was introduced, and after the heat treatment the capsule sizes shrank about 71% (the average size was from 4.9 to 3.5 mum), and the obtained capsules maintained their round shape after water evaporation. The narrowest bandwidth at the 13.5 nm emission in the EUV region was observed when the capsules were irradiated by a CO2 laser with an intensity of 2.9 x 10(10) W/cm (2).

Study of the factors affecting the photoelectrode characteristics of a perylene/phthalocyanine bilayer working in the water phase.

Some types of phthalocyanines (MPc (M = H(2), Cu, or Zn), a p-type semiconductor) were used in combination with 3,4,9,10-perylenetetracarboxyl-bisbenzimidazole (PTCBI, an n-type semiconductor), with which those photoelectrode characteristics in the water phase were investigated in terms of kinetics. Each film of the PTCBI/MPc bilayer functioned as a photoanode, where the photoinduced oxidation of thiol occurs at the MPc/water interface along with the hole conduction through the MPc layer. The holes originate on account of the photophysical events in the p/n interior, involving the charge separation of excitons at the p/n interface. The typical photoelectrochemical characteristic in the PTCBI/MPc photoanodes involved a transient photocurrent occurring in the initial stage under illumination (under potentiostatic conditions): thereafter, it attained a steady state. Moreover, both the initial spiky photocurrents and the steady-state photocurrents exhibited saturation at higher concentrations. An analysis with photoelectrode kinetics was performed by assuming an adsorption step prior to a rate-limiting charge transfer step, where equations were applied to photocurrents based on the Langmuir adsorption equilibrium. The kinetic analyses evidently showed that the photoanodic reactions are kinetically dominated by the charge transfer between MPc and thiol, where the overall kinetics for thiol oxidation decreases in the following order: H(2)Pc > ZnPc > CuPc; that is, it appeared that H(2)Pc acts as the more efficient photofunctional interface capable of oxidation in the water phase when PTCBI was concurrently employed as an electron conductor. Considering that the photocurrent generated is proportional to the surface concentration of thiol (Gamma) at the MPc as well as the intrinsic oxidation rate (cf., ZnPc > H(2)Pc approximately CuPc), the higher efficiency in the output at the H(2)Pc surface was attributed to an exceptionally high Gamma (i.e., from the kinetic analyses, the Gamma value at the H(2)Pc surface was also inferred to be 2-3 times higher than that at the other MPcs). Through the present kinetic analysis, it also revealed that the activity for thiol oxidation taking place at Pc ring is comparable to that at the conventional active catalysts (i.e., polycarboxyphthalocyaninato Co(ii) and Fe(iii)) where a central metal is an active site.

Spectroscopic comparison between 1200 grooves/mm ruled and holographic gratings of a flat-field spectrometer and its absolute sensitivity calibration using bremsstrahlung continuum.

A flat-field extreme ultraviolet (EUV) spectrometer with a varied line spacing groove grating (1200 grooves/mm at grating center) has been developed to study the emission spectra from highly ionized medium Z impurities in large helical device (LHD). It covers a wavelength range of 50-500 A using a mechanically ruled grating, which was later replaced by a newly developed laminar-type holographic grating for comparative studies. Differences in spectral resolution, intensities of higher order spectra, and sensitivities of the spectrometer were studied between the two gratings by observing the emission spectra of LHD plasmas. Although the achieved resolution was alike between them, i.e., deltalambda approximately 0.24 A at 200 A, the holographic grating was much superior in suppressing the higher order light than the ruled grating. The relative sensitivity between the two gratings was evaluated using continuum radiation from LHD plasmas. As a result, it was found that the holographic grating has a flat response in the full wavelength range, but the sensitivity of the ruled grating drops sharply below 200 A. A new technique for the absolute calibration of the EUV holographic grating spectrometer was tried by combining the continuum radiation with a branching ratio of C IV lines (3p-3s: 5800 A/3p-2s: 312 A), and an accurate absolute sensitivity has been successfully obtained.