A5048425067- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Magnetism in coordination complexes
- Organic and Molecular Conductors Research
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Luminescence and Fluorescent Materials
- Organic Light-Emitting Diodes Research
- Spectroscopy and Laser Applications
- Photochemistry and Electron Transfer Studies
- Solid-state spectroscopy and crystallography
- Electronic and Structural Properties of Oxides
- Lanthanide and Transition Metal Complexes
- Advanced Photocatalysis Techniques
- Magnetic and transport properties of perovskites and related materials
- CO2 Reduction Techniques and Catalysts
- Molecular Junctions and Nanostructures
- Perovskite Materials and Applications
- Porphyrin and Phthalocyanine Chemistry
- Advanced Condensed Matter Physics
- Mechanical and Optical Resonators
- Transition Metal Oxide Nanomaterials
- Metal complexes synthesis and properties
- Electron and X-Ray Spectroscopy Techniques
- Electron Spin Resonance Studies
Kyushu University
2017-2025
Azabu University
2014-2025
General Education Center of Iwate
2022
Tokyo Institute of Technology
2009-2019
High Energy Accelerator Research Organization
2019
Japan Science and Technology Agency
2006-2017
Interactive Research and Development
2013
Osaka University
2012
Equilibrium Research
2009
Hefei National Center for Physical Sciences at Nanoscale
2005-2006
Light interacting with nanostructured metals excites the collective charge density fluctuations known as surface plasmons (SP). Through excitation of localized SP eigenmodes incident light is trapped on nanometer spatial and femtosecond temporal scales its field enhanced. Here we demonstrate imaging quantum control dynamics in a silver film. By inducing nonlinear two-photon photoemission from sample pair identical 10-fs laser pulses while scanning pulse delay, record movie fields at rate...
At interfaces of metal oxide and water, partially hydrated or "wet-electron" states represent the lowest energy pathway for electron transfer. We studied photoinduced transfer at H2O/TiO2(110) interface by means time-resolved two-photon photoemission spectroscopy electronic structure theory. approximately 1-monolayer coverage water on hydroxylated TiO2 surfaces, we found an unoccupied state 2.4 volts above Fermi level. Density functional theory shows this to be a wet-electron analogous that...
The coupling of electron and nuclear motions in ultrafast charge transfer at molecule-semiconductor interfaces is central to many phenomena, including catalysis, photocatalysis, molecular electronics. By using femtosecond laser excitation, we transferred electrons from a rutile titanium dioxide (110) surface into CH 3 OH overlayer state that 2.3 ± 0.2 volts above the Fermi level. redistributed was stabilized within 30 femtoseconds by inertial motion substrate ions (polaron formation) and,...
Two-photon photoemission (2PP) spectra of $\mathrm{Ti}{\mathrm{O}}_{2}(110)$ surfaces are measured for the nearly perfect surface, and modified by introduction defects adsorbed molecules. Defects generated on three methods: electron irradiation, annealing in vacuum, ${\mathrm{Ar}}^{+}$ sputtering. Nearly or damaged can be further adsorption ${\mathrm{O}}_{2}$ ${\mathrm{H}}_{2}\mathrm{O}$ 2PP spectroscopy is used to systematically investigate work function change due presence adsorbates....
Correlated electron systems can undergo ultrafast photoinduced phase transitions involving concerted transformations of electronic and lattice structure. Understanding these phenomena requires identifying the key structural modes that couple to states. We report photoresponse molecular crystal Me4P[Pt(dmit)2]2, which exhibits a charge transfer similar between thermally accessible states, demonstrate how femtosecond diffraction be applied directly observe associated motions. Even for such...
Singlet fission (SF), converting a singlet excited state into spin-correlated triplet-pair state, is an effective way to generate spin quintet in organic materials. Although its application photovoltaics as exciton multiplier has been extensively studied, the use of unique degree freedom largely unexplored. Here, we demonstrate that polarization multiexcitons generated by SF improves sensitivity magnetic resonance water molecules through dynamic nuclear (DNP). We form supramolecular...
Singlet fission can generate an exchange-coupled quintet triplet pair state
Abstract Fluorescence imaging, a key technique in biological research, frequently utilizes fluorogenic probes for precise imaging living systems. Tetrazine is an effective emission quencher probe designs, which can be selectively damaged upon bioorthogonal click reactions, leading to considerable enhancement. Despite significant efforts increase the enhancement ratio ( I AC / BC ) of tetrazine‐functionalized probes, influence molecular aggregation on properties has been largely overlooked...
Abstract The photochemistry of fac ‐[Re(bpy)(CO) 3 Cl] ( 1 a ; bpy=2,2′‐bipyridine) initiated by irradiation using <330 nm light has been investigated. Isomerization proceeded in THF to give the corresponding mer‐ isomer b . However, presence small amount MeCN, main product was CO‐ligand‐substituted complex OC ‐6‐24)‐[Re(bpy)(CO) 2 Cl(MeCN)] c bpy=2,2′‐bipyridine). In two isomers, and its ‐6‐34) form ), were produced. Only thermally isomerized produce ‐6‐44) A detailed investigation led...
Aromaticity of photoexcited molecules is an important concept in organic chemistry. Its theory, Baird's rule for triplet aromaticity since 1972 gives the rationale photoinduced conformational changes and photochemical reactivities cyclic π-conjugated systems. However, it still challenging to monitor dynamic structural change induced by excited-state aromaticity, particularly condensed materials. Here we report direct observation a molecular motion subsequent packing deformation accompanied...
This work reviews the experimental studies on photo-induced cooperative phenomena (photo-induced phase transitions, PIPT), which are related to ultrafast structural and electronic-state dynamics. The review includes a brief history of this research field. current growth PIPT is facilitated by deep collaboration between quantum beam science materials science. Meanwhile, owing developments in technology, concept itself has largely expanded. In initial stage research, dynamical process was...
The highest efficiency of heavy metal-free visible-to-UV photon upconversion is achieved by employing a ketocoumarin sensitizer with strong visible absorption, weak UV and high intersystem crossing efficiency.
This study reports the facile syntheses of tetra-boron difluoride (tetra-BF2 ) complexes, flag-hinge-like molecules that exhibit intense green-to-orange luminescence in solution and yellow-to-red emission solid states. Single-crystal structure analysis density functional theory calculations suggested a bent this series compounds. The complexes also exhibited excellent optical properties, with quantum yields reaching 100 % large Stokes shift. These properties were attributed to altered...
Fast room-temperature phosphorescence with high quantum yields up to 38% in solution from metal-free organic 1,2-diketones is reported, along the mechanism and molecular design principles governing fast phosphorescence.
The quasistable state in the photoinduced phase transition for quasi-one-dimensional quarter-filled organic conductor $(\mathrm{EDO}\mathrm{\text{\ensuremath{-}}}\mathrm{TTF}{)}_{2}{\mathrm{PF}}_{6}$ has been examined by ultrafast reflective measurements and time-dependent model calculations incorporating both electron-electron electron-phonon interactions. transient optical conductivity spectrum over a wide probe photon-energy range revealed that photoexcitation induced new type of...
Time-resolved IR spectra indicated fast electron transfer from the reduced photosensitizer to catalyst.
Much effort has been devoted to the development of techniques probe carrier dynamics, which govern many semiconductor device characteristics. We report direct imaging electron dynamics on surfaces by time-resolved photoemission microscopy using femtosecond laser pulses. The experiments utilized a variable-repetition-rate system suppress sample charging problems. recombination photogenerated electrons and lateral motion driven an external electric field GaAs surface were visualized. mobility...
Thermally activated delayed fluorescence (TADF) molecules are gathering attention for their potential to boost the efficiency of organic light-emitting diodes without precious metals. Minimizing energy difference between S1 and T1 states (Δ EST) is a fundamental strategy accelerate reverse intersystem crossing (RISC). However, lack microscopic understanding process prevents adequate design strategies efficient TADF materials. Here, we focused on four carbazole-benzonitrile (Cz-BN)...
The supramolecular photocatalysts in which a Ru(II) complex as molecular redox photosensitizer unit and Re(I) catalyst are connected with various alkyl or ether chain have attracted attention because they can efficiently photocatalyze CO2 reduction high durability selectivity of CO formation, especially on solid materials such semiconductor electrodes mesoporous organosilica. intramolecular electron transfer from the one-electron reduced to unit, follows excitation subsequent reductive...
Photophysical properties of europium (Eu(III)) complexes are affected by ligand-to-metal charge transfer (LMCT) states. Two luminescent Eu(III) with three tetramethylheptadionates (tmh) and pyridine (py), [Eu(tmh)3(py)1] (seven-coordinated monocapped-octahedral structure) [Eu(tmh)3(py)2] (eight-coordinated square antiprismatic structure), were synthesized for geometrical-induced LMCT level control. Distances between oxygen atoms tmh ligands estimated using single-crystal X-ray analyses. The...
Abstract The electronic structure and photophysics of the recently designed organic direct singlet harvesting (DSH) molecule are explored, in which donor (D) acceptor (A) held at distance by two bridges. One bridges is functionalized with fluorene. This leads to an ultrasmall singlet–triplet energy gap ∆ E ( S 1 − T ) ≈ 10 cm −1 (≈1 meV) between charge transfer states 1,3 CT shows energetically close‐lying 3 ππ * state localized on Dielectric constant variation environment crossing near ε =...
Femtosecond optical response was investigated on a perovskite-type cobalt oxide, Pr0.5Ca0.5CoO3 during an insulator-metal (I-M) transition accompanied with the change in spin configuration. After photoirradiation at 30 K, reflectivity showed sudden and large increase subsequent variation depending observed photon energy. An exact calculation of Maxwell's equations for after enabled us to observe ultrafast dynamics I-M phase motion photonically created metallic domain velocity ultrasonic wave.