A5072562074- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Near-Field Optical Microscopy
- Gold and Silver Nanoparticles Synthesis and Applications
- Plasmonic and Surface Plasmon Research
- Quantum Dots Synthesis And Properties
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Photoreceptor and optogenetics research
- Advanced Chemical Physics Studies
- Laser-Matter Interactions and Applications
- Photochromic and Fluorescence Chemistry
- Advanced Fiber Laser Technologies
- Advanced Fluorescence Microscopy Techniques
- Photosynthetic Processes and Mechanisms
- Chalcogenide Semiconductor Thin Films
- Organic Electronics and Photovoltaics
- Photonic Crystal and Fiber Optics
- Porphyrin and Phthalocyanine Chemistry
- Graphene research and applications
- Advanced biosensing and bioanalysis techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Analytical Chemistry and Sensors
- Laser Design and Applications
- Molecular spectroscopy and chirality
Kyoto Institute of Technology
1998-2024
Politecnico di Milano
2019-2024
Istituto di Fotonica e Nanotecnologie
2018-2021
Hiroshima University
2008-2011
Wakayama University
2009
Institute for Molecular Science
2003-2006
National Institutes of Natural Sciences
2004-2006
Kyushu University
2006
The Graduate University for Advanced Studies, SOKENDAI
2004-2005
Kyoto University
2005
We investigated the two-photon-induced photoluminescence properties of single gold nanorods by scanning near-field spectroscopy. The process was found to be initiated a sequential one-photon absorption for creating pair an electron and hole in sp d bands. Photoluminescence is then radiated when near Fermi surface recombines with X L symmetry points. polarization characteristics emitted photons from regions were different. These can understood crystalline structure band nanorod....
We have investigated two-photon-induced photoluminescence images and spectra of single gold nanorods by using an apertured scanning near-field optical microscope. The observed PL spectrum nanorod can be explained the radiative recombination electron-hole pair near X L symmetry points. reveal characteristic features reflecting eigenfunction a specific plasmon mode as well electric field distributions around nanorod.
We have investigated optical properties of single gold nanorods by using an apertured-type scanning near-field microscope. Near-field transmission spectrum nanorod shows several longitudinal surface plasmon resonances. Transmission images observed at these resonance wavelengths show oscillating pattern along the long axis nanorod. The number oscillation increases with decrement observing wavelength. These spatial characteristics were well reproduced calculated local density-of-states maps...
Abstract A critical bottleneck for improving the performance of organic solar cells (OSC) is minimising non-radiative losses in interfacial charge-transfer (CT) state via formation hybrid energetic states. This requires small offsets often detrimental high external quantum efficiency (EQE). Here, we obtain OSC with both voltage (0.24 V) and photocurrent (EQE > 80%) simultaneously minimised. The CT states separate into free carriers ≈40-ps time constant. We combine device spectroscopic...
Recently, it was demonstrated that charge separation in hybrid metal–semiconductor nanoparticles (HNPs) can be obtained following photoexcitation of either the semiconductor or localized surface plasmon resonance (LSPR) metal. This suggests intriguing possibility photocatalytic systems benefiting from both and exciton excitation, main challenge being to outcompete other ultrafast relaxation processes. Here we study CdSe-Au HNPs using spectroscopy with high temporal resolution. We describe...
Structurally well-defined graphene nanoribbons (GNRs) are nanostructures with unique optoelectronic properties. In the liquid phase, strong aggregation typically hampers assessment of their intrinsic Recently we reported a novel type GNRs, decorated aliphatic side chains, yielding dispersions consisting mostly isolated GNRs. Here employ two-dimensional electronic spectroscopy to unravel optical properties GNRs and disentangle transitions underlying broad rather featureless absorption band....
We investigated the near-field optical properties of single gold nanorods. Transmission images observed near surface plasmon resonances agree qualitatively with calculated maps local density states and are reflected by spatial characteristics wave functions. Ultrafast temporal responses have been combining microscopy a time-resolved technique. It has found that behavior collective motion electrons in center rod is different from both ends.
We report a novel type of structurally defined graphene nanoribbons (GNRs) with uniform width 1.7 nm and average length up to 58 nm. These GNRs are decorated pending Diels-Alder cycloadducts anthracenyl units N- n-hexadecyl maleimide. The resultant bulky side groups on afford excellent dispersibility concentrations 5 mg mL-1 in many organic solvents such as tetrahydrofuran (THF), two orders magnitude higher than the previously reported GNRs. Multiple spectroscopic studies confirm that dilute...
We have investigated two-photon-induced photoluminescence (PL) properties of single gold nanoplates by using an apertured scanning near-field optical microscope. The show PL much stronger than nanorods. images characteristic spatial features, which depend on the incident polarization. These are in good agreement with calculated distribution electric fields adjacent to particles at excitation wavelength. attribute observed characteristics plasmon modes.
Thin films of chiral porphyrin J-aggregates have been studied by vibrationally and electronically doubly resonant sum frequency generation (SFG) spectroscopy. It was revealed that the supramolecular structures aggregates in solutions were retained thin film samples, their chirality determined using vibrational SFG Electronic resonance profiles some bands achiral different from each other, both distinct electronic absorption spectra. To account for these peculiar profiles, we proposed...
A novel apparatus for time-resolved near-field optical microscopy is described. The consists of a mode-locked Ti:sapphire laser, microstructure fiber, and scanning microscope equipped with an apertured fiber probe. probe pulses in visible to near-infrared regions are generated by focusing laser the fiber. broadband continuum can be used as wavelength-tunable light source fluorescence excitation well probing absorption excited states at arbitrary wavelengths applying pump-probe scheme, high...
Metal-halide perovskites show excellent properties for photovoltaic and optoelectronic applications, with power conversion efficiencies of solar cell LEDs exceeding 20%. Being solution processed, these polycrystalline materials likely contain a large density defects compared to melt-grown semiconductors. Surprisingly, typical effects from (absorption below the bandgap, low fill factor open circuit voltage in devices, strong nonradiative recombination) are not observed. In this work, we study...
Abstract Doubly resonant sum‐frequency generation (DR‐SFG) spectroscopy of fluorescein‐4‐isothiocyanate isomer‐I (FITC) monolayers on platinum was performed. Vibrational spectra the for IR wavenumber 1750–1450 cm −1 were measured with visible probes ranging from 431 to 582 nm. Two vibrational bands at 1643 and 1610 observed, their DR‐SFG excitation profiles displayed different shapes. By rinsing an alkaline solution, smaller band disappeared larger gained intensity. On basis spectral...
A novel method for compressing a laser pulse, using combination of transient stimulated Raman scattering and pump-probe technique, is proposed. The approach does not require short in contrast to reported based on impulsive scattering. observed spectrum was sufficiently broad generate sub-10 fs pulse. In fact, 100-fs pulse the near-ultraviolet region compressed sub-30 fs. Further compression would be achieved by compensating phase distortion, as suggested from data spectral phase.
We fabricated porphyrin thin films on mica surfaces from acidic aqueous solutions of the preorganized H-aggregates amphiphilic porphyrins by simple spin-coating method. The morphological and spectroscopic properties film were investigated scanning near-field optical microscopy. results obtained in this study demonstrate that structure solution can be transferred as a with thickness monolayer level without losing their substantial photophysical properties.
We have synthesized double-chain disulfides of adenine with different chain lengths (n = 2, 4, 5, 9, and 10) studied their self-assembled monolayers (SAM) on gold surface by IR-UV doubly resonant sum frequency generation spectroscopy the help DFT calculation. A versatile way to investigate orientation angle functional groups SAMs coverage has been demonstrated. It was revealed that IR dipoles band at around 1630 cm−1, which were almost parallel long molecular axis ring, less tilted respect...
Using broadband transient absorption in a high efficiency (>11%) photovoltaic blend with non-fullerene acceptor, we observe instantaneous (sub-30 fs) charge separation, demonstrating close to ideal donor-acceptor level matching and nanomorphology this blend.
By means of subpicosecond and nanosecond laser photolysis the title compounds (MAQ DMAQ), it is concluded that both lowest excited singlet triplet states undergo intramolecular hydrogen-atom transfer corresponding biradicals thus generated yield 9-hydroxy-1,10-anthraquinone-1-methide from MAQ 9-hydroxy-4-methyl-1,10-anthraquinone-1-methide DMAQ. Although these methides are stable at 77 K, they revert to original anthraquinones a higher temperature than K. In ethanol EPA (diethyl...