A5072336543- Gold and Silver Nanoparticles Synthesis and Applications
- Molecular Junctions and Nanostructures
- Plasmonic and Surface Plasmon Research
- Quantum Dots Synthesis And Properties
- Advanced biosensing and bioanalysis techniques
- Polymer Surface Interaction Studies
- Force Microscopy Techniques and Applications
- Nanofabrication and Lithography Techniques
- Photochromic and Fluorescence Chemistry
- Perovskite Materials and Applications
- Nanomaterials and Printing Technologies
- Advanced Biosensing Techniques and Applications
- Optical Coatings and Gratings
- GaN-based semiconductor devices and materials
- Nanocluster Synthesis and Applications
- Nanowire Synthesis and Applications
- Photonic Crystals and Applications
- Surface and Thin Film Phenomena
- Electrochemical Analysis and Applications
- Surfactants and Colloidal Systems
- Nanotechnology research and applications
- Advanced Fluorescence Microscopy Techniques
- Chalcogenide Semiconductor Thin Films
- nanoparticles nucleation surface interactions
- Quantum and electron transport phenomena
Kyushu University
2016-2025
Tohoku University
2008-2024
Advanced Institute of Materials Science
2020-2024
ORCID
2020
Osaka Prefecture University
2018
Institute of Systems, Information Technologies and Nanotechnologies
2018
Tokyo Institute of Technology
2002-2011
National Institute of Advanced Industrial Science and Technology
1998-2008
National University of Singapore
2002-2008
RIKEN
1996-2008
n-Alkanethiol (CnH2n+1SH) self-assembled monolayers (SAMs) adsorbed on Au(111) were studied with an atomic force microscope (AFM) to confirm the influence of lateral interaction between thiols film morphology. Two experiments performed: firstly, a study domain formation at initial stage SAM growth (single component) and, secondly, investigations coadsorption phenomenon in mixed SAMs composed two alkanethiols having different chain lengths. For kinetics study, was immersed into 10-2 mM...
Gold nanoparticles capped by an unsymmetrical azobenzene disulfide, 4-hexyl-4'-(12-(dodecyldithio)dodecyloxy)azobenzene (C6AzSSC12), were synthesized in order to investigate the efficiency of photoisomerization on colloidal gold surfaces. The a two-step method avoid direct contact units with reducing agent. average size particles was determined be ∼5.2 ± 1.3 nm from transmission electron microscope (TEM) images. CH2 antisymmetric (∼2919 cm-1) and symmetric (∼2850 stretching bands FTIR...
Abstract Field-induced ionic motions in all-inorganic CsPbBr 3 perovskite quantum dots (QDs) strongly dictate not only their electro-optical characteristics but also the ultimate optoelectronic device performance. Here, we show that functionality of a single Ag/CsPbBr /ITO can be actively switched on sub-millisecond scale from resistive random-access memory (RRAM) to light-emitting electrochemical cell (LEC), or vice versa, by simply modulating its bias polarity. We then realize for first...
Lead halide perovskite nanocrystals (LHP NCs) have attracted significant attention as next-generation semiconductor nanomaterials due to their near-unity photoluminescence quantum yields and tunable emission wavelengths. Despite outstanding optical properties,...
We have applied nanoporous anodic alumina films as planar optical waveguides and studied changes in the effective dielectric constants of these thin due to various processes occurring pores. demonstrate potential porous waveguide for high sensitivity (bio-) chemical sensing with bovine serum albumin adsorption desorption at pH values, subangstrom thickness protein adsorbed. also monitored pore widening (alumina dissolution) sensitivity, which is conceptually reverse detecting conformal film...
This paper delves into the strategic design and optimization of silver (Ag) nanostructured arrays within plasmonic metamaterials, targeting enhancement imaging sensitivity. Leveraging Finite-Difference Time-Domain (FDTD) simulations, our research rigorously compares various Ag geometries, including nanospheres, nanocones, nanodisks, nanocubes. The aim is to pinpoint configurations that significantly enhance electric field localization on surfaces nanostructures, a pivotal factor. nanocube...
The structures of semifluorinated alkanethiol self-assembled monolayers (SAMs) generated by the adsorption CF3(CF2)9(CH2)nSH (F10HnSH, n = 2, 6, 11, 17, 33) onto gold were investigated with atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and surface plasmon resonance spectroscopy. Images obtained AFM F10H2SH SAM showed a remarkably ordered 2D hexagonal lattice constant, 5.9 ± 0.1 Å, on Au(111)/mica. As total number carbon atoms in alkyl spacer groups (n) was increased,...
The microstructure, wettability, and thermal stability of self-assembled monolayers (SAMs) on gold generated from semifluorinated alkanethiols F(CF2)10(CH2)nSH, where n = 2, 6, 11, 17, 33 (F10HnSH), were examined by polarization modulation infrared reflection absoprtion spectroscopy (PM-IRRAS) dynamic contact angle measurements. Analysis PM-IRRAS revealed that the length methylene spacer (Hn) influenced tilt fluorocarbon segments in SAMs. As was increased, perfluorocarbon moiety increased...
Asymmetric dialkyl disulfides with a para-substituted azobenzene (i.e., 4-substituted 4'-(12-(dodecyldithio)dodecyloxy)azobenzenes) produced photoresponsive self-assembled monolayers (SAMs) on gold (111) surfaces. Infrared reflection absorption (IR-RA) spectroscopy and ultraviolet (UV) visible (vis) light gave information the molecular orientational order of adsorbates in SAMs. The photoreactivity was investigated using dynamic contact-angle measurements Wilhelmy-type surface balance....
Ultrathin films of a poly(styrene)-block-poly(2-vinylpyrindine) diblock copolymer (PS-b-P2VP) and poly(styrene)-block-poly(4-vinylpyrindine) (PS-b-P4VP) were used to form surface-induced nanopattern (SINPAT) on mica. Surface interaction controlled microphase separation led the formation chemically heterogeneous surface nanopatterns dry ultrathin films. Two distinct nanopatterned surfaces, namely, wormlike dotlike patterns, investigate influence topography in nanometer range cell adhesion,...
This paper describes unique plasmonic characteristics of two dimensional (2D) crystalline sheets composed homogeneous Ag nanoparticles (AgNPs) fabricated by the Langmuir-Schaefer method at an air-water interface. The localized surface plasmon resonance (LSPR) band nanosheet was tuned changing interparticle distance AgNPs via length organic capping molecules. Red shift LSPR sheet followed exponential law against in a similar manner to previous reports metal nanodisc pairs. However, much...
Size control is critical in the synthesis of quantum-confined semiconductor nanocrystals, otherwise known as quantum dots. The achievement size-uniformity and narrow spectral line-width dots conventionally relies on a very precise kinetic reactions, where reaction time plays significant role defining final crystal sizes distribution. Here, we show that perovskite nanostrips could be achieved through thermodynamically controlled reaction, using low-temperature ligand-rich approach. nanostrip...
The structure and growth of functionalized thiol self-assembled monolayers (SAMs) on Au(111) derived from a new compound, 12-(4-((4-hexylphenyl)azo)phenoxy)dodecane-1-thiol ("hexyl azobenzene thiol"), were examined by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), dynamic contact angles, Fourier transform infrared-reflection absorption (FTIR-RAS), reflection UV−vis spectroscopy. hexyl SAM showed adsorption kinetics comparable to that alkanethiols. At the initial stage...
In this paper, we report on in situ optical/electrochemical investigations using a combination of surface plasmon resonance spectroscopy and electrochemistry order to determine the complex dielectric constants poly(3,4-ethylenedioxythiophene) (PEDOT) thin films. The PEDOT films were deposited by electropolymerization. film thickness was monitored quartz crystal microbalance. electrochemical (EC-SPR) measurements, three wavelengths corresponding interband intraband electronic transition...
Abstract Self‐assembled monolayers (SAMs) formed from semifluorinated alkanethiols (SFATs) CF 3 (CF 2 ) 9 (CH n SH (F10HnSH: = 2, 11, and 17) on poly‐crystalline Au Ag were characterized by X‐ray photoelectron spectroscopy, infrared reflection absorption near edge fine structure spectroscopy. SFATs found to form highly ordered densely packed SAMs both substrates. The molecules are strongly bonded the substrates via their sulfur head groups, in same manner as conventional alkanethiol (AT)...
We report the characteristics of azobenzene-containing self-assembled monolayers (SAMs) which are designed and synthesized for surface photoisomerization reactions. The photoreactive SAMs were composed unsymmetrical azobenzene disulfides, in free volumes photoreaction moieties guaranteed by 50% dilution dye functions at molecular level on surface. photoswitching reaction was monitored situ through change optical film thickness means plasmon spectroscopy. influences alkyl side chain length...
The interactions between colloidal particles and nanoparticles determine solution stability the structures formed when are unstable to flocculation. Therefore, knowledge of interparticle is important for understanding transport, dissolution, fate in environment. governed by surface properties particles, which altered species adsorb surface. environment almost never those bare but rather that have been modified adsorption natural organic materials. Citric acid this regard not only because it...
The formation of periodic arrangements two types nanoparticles (NPs), i.e., binary NP superlattices (BNSLs), provides a versatile approach to control their physical properties through interparticle interactions. However, achieving highly ordered BNSLs is still challenging because the difficulty combining distinct NPs without phase segregation. In this work, plasmonic Au and CdS quantum dots (QDs) modified with dodecanethiol ligands were assembled into multilayered structures by alternately...
Biotin-capped gold nanoparticles assembled on flat with volume fraction f are studied by surface plasmon resonance (SPR) spectroscopy and atomic force microscopy (AFM) in order to estimate the dielectric function of based Maxwell−Garnett (MG) theory. The complex (ε', ε'') spherical at three representative wavelengths vis−near-IR region, i.e., λ = 543, 632.8, 1152 nm, is estimated for a homogeneously covered discuss wavelength dependence function. SPR response particles 2D aggregates also...