Showing papers by "Toshiharu Teranishi published in 2013"
TL;DR: In this article, the controllable synthesis of uniform Au@Ag heterogeneous nanorods (NRs) by coreduction of gold and silver sources in a one-pot polyol reaction is presented.
Abstract: It generally requires a complex workup procedure for the fabrication of Au@Ag heterogeneous nanostructures with an accurate morphology by the present multistep seed-mediated growth approaches. In this paper, we present a new and straightforward method for the controllable synthesis of uniform Au@Ag heterogeneous nanorods (NRs) by coreduction of gold and silver sources in a one-pot polyol reaction. High-quality Au@Ag heterogeneous NRs of various aspect ratios were facilely and selectively produced in high concentration by tuning the initial experimental parameters. Our synthetic approach is highlighted by its simplicity, large-scale production, and controllability of the synthesis. Our study indicates the oxidative etching by O2/Cl– pairs plays a key role for the high-yield synthesis of uniform Au@Ag heterogeneous NRs. The size-dependent optical properties of Au@Ag heterogeneous NRs were first and systematically investigated. Our experiments reveal that Au@Ag heterogeneous NRs exhibit two strong absorption...
90 citations
TL;DR: In this paper, a gradual size control of polyvinyl-2-pyrrolidone-protected Rh nanoparticles (PVP-Rh NPs) was successfully achieved in the range of 1.7-7.7 nm by tuning the pH value and the reaction temperature of the ethylene glycol (EG) solution; smaller NPs were formed at higher pH and at higher temperature.
Abstract: A gradual size control of poly(N-vinyl-2-pyrrolidone)-protected Rh nanoparticles (PVP-Rh NPs) was successfully achieved in the range of 1.7–7.7 nm by tuning the pH value and the reaction temperature of the ethylene glycol (EG) solution; smaller NPs were formed at higher pH and at higher temperature. This trend can be interpreted by the change in the nucleation rate caused by tuning the pH value and/or the temperature of the solution. When the size tuned PVP-Rh NPs were applied for use as cocatalysts in a photocatalyst (solid solution of GaN and ZnO (Ga1–xZnx)(N1–xOx)) for overall water splitting under visible light, it was demonstrated that smaller Rh cores gave higher activity than the larger ones.
70 citations
TL;DR: In this paper, the charge separation properties of type-II semiconductor heterodimers composed of chalcogenide-chalcogenides blends were investigated and a staggered alignment of band edges at the heterointerface was proposed to promote the spatial charge separation between electrons and holes in different parts of the heterostructure.
Abstract: Highly efficient photoenergy conversion in semiconductor nanoparticle heterostructures requires the formation of epitaxial heterointerfaces and band alignment engineering. This requirement has led to attention being given to recent advances and prospects in the charge separation properties of type-II semiconductor heterodimers composed of chalcogenide–chalcogenide blends. Type-II semiconductor heterodimers with a staggered alignment of band edges at the heterointerface can be synthesized by seeded growth or ion exchange to promote the spatial charge separation between electrons and holes in different parts of the heterostructure. Special attention has been given to CdS–Cu2–xS (0 ≤ x ≤ 0.0625) and CdS–CdTe combinations where CdS is a commonly used n-type semiconductor and both Cu2–xS and CdTe are proper p-type semiconductors that are used as light absorbers in heterojunction solar cells.
63 citations
TL;DR: Quantitative analysis of the OFF state decays shows that electron transfer occurs even in the presence of fast non-radiative pathways in charged systems.
Abstract: Time-resolved photoluminescence (PL) and transient absorption (TA) spectroscopy are conducted in order to get knowledge on the excited state of CdSe nanorods (NR), and to assess the impact of Au nanoparticles (NP) on the carrier dynamics of hybrid Au–CdSe NRs. The decay dynamics measured in solution show an increase of non-radiative decay channels in the presence of Au NPs, whose characteristic lifetimes vary from a few ps to tens of ps. The ultrafast electron transfer from CdSe NRs to Au NPs efficiently competes with intraband relaxation dynamics, allowing observation of the hot-electron transfer process. Furthermore, the time-averaged PL decay of CdSe NRs shows a strongly multiexponential feature that was analyzed by single-particle spectroscopy. The PL decay of individual NRs fluctuates in time and is correlated with the PL intensity. We show that the time-averaged decay of bare CdSe NRs is composed of (i) a long lifetime component corresponding to bright CdSe NRs (ON state) and (ii) a short lifetime component corresponding to charged NRs that open additional fast non-radiative channels (OFF state). When Au NPs are attached to CdSe NRs, the ON state PL decays still show a long lifetime component, suggesting that the length of the NRs may hinder electron transfer if the exciton is formed far from the Au NPs. Finally, quantitative analysis of the OFF state decays shows that electron transfer occurs even in the presence of fast non-radiative pathways in charged systems.
37 citations
TL;DR: In this article, the authors investigated the random telegraph signals in a chemically assembled single-electron transistor (SET) at temperatures as low as 300 mK and found that the dwell time of the RTS was dependent on the drain voltage of the SET, but was independent of the gate voltage.
Abstract: We have studied random telegraph signals (RTSs) in a chemically assembled single-electron transistor (SET) at temperatures as low as 300 mK. The RTSs in the chemically assembled SET were investigated by measuring the source–drain current, using a histogram of the RTS dwell time, and calculating the power spectrum density of the drain current–time characteristics. It was found that the dwell time of the RTS was dependent on the drain voltage of the SET, but was independent of the gate voltage. Considering the spatial structure of the chemically assembled SET, the origin of the RTS is attributed to the trapped charges on an alkanethiol-protected Au nanoparticle positioned near the SET. These results are important as they will help to realize stable chemically assembled SETs in practical applications.
15 citations
TL;DR: In this article, a SiNx-passivated chemically assembled single-electron transistors (SETs) were constructed by bottom-up processes involving electroless Au plating and the chemisorption of Au nanoparticles.
Abstract: We report the elaboration of SiNx-passivated chemically assembled single-electron transistors (SETs) by bottom-up processes involving electroless Au plating and the chemisorption of Au nanoparticles. With a Au top-gate electrode, the SiNx-passivated SETs showed a clear Coulomb diamond at 9 K and the top-gate capacitance was 17 times larger than the side-gate capacitance. Moreover, Coulomb oscillation and the Coulomb diamond were observed even at 160 K. Thus, planar technology is applicable to chemically assembled SETs.
11 citations
TL;DR: Novel rigid bidentate ligands are designed to demonstrate their size focusing effect on the gold NPs (AuNPs) and are shown to passivate the inorganic nanoparticles (NPs).
Abstract: Multidentate organic ligand molecules have potentials not only to passivate the inorganic nanoparticles (NPs) but also to tune their structures and functions. Here, we designed novel rigid bidentate ligands to demonstrate their size focusing effect on the gold NPs (AuNPs).
7 citations
TL;DR: Anisotropic phase-segregated CdS-Cu31S16 heterodimers with type-II band alignment were spontaneously formed by selective growth of monoclinic Cu31S 16 phases on preformed hexagonal cdS phases as mentioned in this paper.
Abstract: Anisotropically phase-segregated CdS–Cu31S16 heterodimers with type-II band alignment were spontaneously formed by selective growth of monoclinic Cu31S16 phases on preformed hexagonal CdS phases. The photo-induced carrier dynamics of the heterodimer was investigated by fluorescence and transient absorption measurements.
7 citations
Patent•
27 Feb 2013
TL;DR: In this paper, a nanodevice is provided with: a first insulating layer (2), one electrode (5A) and another electrode(5B) that are provided so as to comprise a nanogap on the first layer, and a metal nanoparticle (7) or a functional molecule that is placed between the one electrode and the other layer.
Abstract: Provided are: a nanodevice which is combined with electronic devices such as a diode, a tunnel element and a MOS transistor; an integrated circuit; and a nanodevice manufacturing method. The nanodevice is provided with: a first insulating layer (2); one electrode (5A) and another electrode (5B) that are provided so as to comprise a nanogap on the first insulating layer (2); a metal nanoparticle (7) or a functional molecule that is placed between the one electrode (5A) and the other electrode (5B); and a second insulating layer (8) that is provided on the first insulating layer (2), the one electrode (5A) and the other electrode (5B), and that buries either the metal nanoparticle (7) or the functional molecule. The second insulating layer (8) functions as a passivation layer.
2 citations
Patent•
27 Feb 2013
TL;DR: In this paper, the authors proposed a nanodevice, which is a combination of an electronic device such as a diode, tunnel device and MOS transistor, integrated circuit and manufacturing method.
Abstract: This invention is to provide a nanodevice, which is combined with an electronic device such as a diode, tunnel device and MOS transistor, integrated circuit and manufacturing method of the nanodevice. A nanodevice includes: a first insulating layer 2 ; one electrode 5 A and the other electrode 5 B provided to have a nanogap on the first insulating layer 2 ; a metal nanoparticle or a functional molecule provided between the one electrode 5 A and the other electrode 5 B; a second insulating layer 8 provided on the first insulating layer 2 , and on the one electrode 5 A and the other electrode 5 B to embed the metal nanoparticle or the functional molecule. The second insulating layer works as a passivating layer.
1 citations
30 Jun 2013
TL;DR: In this article, a comprehensive photoacoustic measurement of various gold nanoparticles was performed to design exogenous imaging agents for enhancing the contrast, and the signal intensities were sensitive to the shape and size of the gold particles.
Abstract: We performed a comprehensive photoacoustic measurement of various gold nanoparticles to design exogenous imaging agents for enhancing the contrast. The photoacoustic signal intensities were sensitive to the shape and size of the gold nanoparticles.
Posted Content•
TL;DR: In this paper, the authors investigated the resonant elastic scattering of proton resonant states in Ne and found four resonances, i.e., 6.15, 6.30 and 7.05 MeV, were observed clearly.
Abstract: Proton resonant states in $^{18}$Ne have been investigated by the resonant elastic scattering of $^{17}$F+$p$. The $^{17}$F beam was separated by the CNS radioactive ion beam separator (CRIB), and bombarded a thick H$_2$ gas target at 3.6 MeV/nucleon. The recoiled light particles were measured by using three sets of ${\Delta}$E-E Si telescope at scattering angles of $\theta$$_{lab}$$\approx 3^\circ$, 10$^\circ$ and 18$^\circ$, respectively. Four resonances, {\it i.e.}, at $E_{x}$=6.15, 6.30, 6.85, and 7.05 MeV, were observed clearly. By $R$-matrix analysis of the excitation functions, $J^{\pi}$=1$^-$ was firmly assigned to the 6.15 MeV state which is a key state in calculating the reaction rate of $^{14}$O($\alpha$,$p$)$^{17}$F reaction. This reaction was thought to be one of the most probable key reactions for the breakout from the hot-CNO cycle to the $rp$-process in type I x-ray bursts In addition, a new excited state observed at $E_{x}$=6.85 MeV was tentatively assigned as 0$^{-}$, which could be the analog state of 6.880 MeV, 0$^{-}$ in mirror $^{18}$O.