A5008622486- Fullerene Chemistry and Applications
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Graphene research and applications
- Carbon Nanotubes in Composites
- Synthesis and Properties of Aromatic Compounds
- Boron and Carbon Nanomaterials Research
- Advanced Chemical Physics Studies
- Crystallography and molecular interactions
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Advanced NMR Techniques and Applications
- Chemical Reactions and Mechanisms
- Astrophysics and Star Formation Studies
- Luminescence and Fluorescent Materials
- Organic Light-Emitting Diodes Research
- Porphyrin and Phthalocyanine Chemistry
- Atomic and Molecular Physics
- Chalcogenide Semiconductor Thin Films
- Diamond and Carbon-based Materials Research
- Advanced Physical and Chemical Molecular Interactions
- Quantum, superfluid, helium dynamics
- Organic Chemistry Cycloaddition Reactions
Kyoto University
2016-2025
Kyoto University Institute for Chemical Research
2016-2025
Kyoto Bunkyo University
2016-2025
Instituto de Investigaciones Químicas
2005-2024
Kyoto College of Medical Science
2018-2021
Japan Science and Technology Agency
2005-2016
Universidad Autónoma de Madrid
2016
Brown University
2006-2013
Tohoku University
2001-2013
Fukui University of Technology
2007-2012
Abstract Efficient organic light-emitting diodes have been developed using emitters containing rare metals, such as platinum and iridium complexes. However, there is an urgent need to develop composed of more abundant materials. Here we show a thermally activated delayed fluorescence material for diodes, which realizes both approximately 100% photoluminescence quantum yield up-conversion the triplet singlet excited state. The contains electron-donating diphenylaminocarbazole...
In spite of their importance in fundamental and applied studies, the preparation endohedral fullerenes has relied on difficult-to-control physical methods. We report a four-step organic reaction that completely closes 13-membered ring orifice an open-cage fullerene. This process can be used to synthesize fullerene C60 encapsulating molecular hydrogen, which isolated as pure product. surgical method should make possible series fullerenes, either small atoms or molecules, are not accessible by...
Water normally exists in hydrogen-bonded environments, but a single molecule of H(2)O without any hydrogen bonds can be completely isolated within the confined subnano space inside fullerene C(60). We bulk quantities such by first synthesizing an open-cage C(60) derivative whose opening enlarged situ at 120°C that quantitatively encapsulated one water under high-pressure conditions. The relatively simple method was developed to close cage and encapsulate water. structure H(2)O@C(60)...
The dynamic optical properties of perovskite CH3NH3PbI3 single crystals were studied by means time-resolved photoluminescence (PL) spectroscopy at room temperature. PL peak under one-photon excitation exhibits a red-shift with elapsing time, while two-photon is time-independent and appears lower energy levels. low-energy can be attributed to emissions from the localized states because strong band-to-band absorption photon re-absorption emitted light in interior region. We revealed that...
Recent attempts at the synthesis of endohedral fullerenes by organic reactions, so-called "molecular surgery" methods, are surveyed. The creation an opening on surface fullerene cages allowed insertion He, H(2), H(2)O, or CO within cages. An effective route to "suture" was established realize a new fullerene, H(2)@C(60). Further development this operation as well properties and reactions H(2)@C(60) summarized. Also application encapsulated H(2) molecule NMR probe for study aromaticity ionic...
Abstract Triarylboron compounds have attracted much attention, and found wide use as functional materials because of their electron‐accepting properties arising from the vacant p orbitals on boron atoms. In this study, we design synthesize new donor–acceptor triarylboron emitters that show thermally activated delayed fluorescence. These display sky‐blue to green emission high photoluminescence quantum yields 87–100 % in host matrices. Organic light‐emitting diodes using these emitting...
Two-dimensionally expanded π-systems, consisting of partially oxygen-bridged triarylamine skeletons that are connected to an azulene (1–3) or biphenyl core (4), were synthesized and characterized. When tetra-substituted 1 was used as a hole-transporting material (HTM) in perovskite solar cells, the observed performance (power conversion efficiency = 16.5%) found be superior current HTM standard Spiro-OMeTAD. A comparison hole mobility, ability control HOMO LUMO levels, hole-collection at...
Lead halide complexes formed during the fabrication of perovskite (CH3NH3PbI3)-based solar cells were examined by single-crystal X-ray diffraction analysis. Based on observed results, protocol using a sequential deposition method was optimized to reproducibly provide highly efficient with power conversion efficiencies more than 10%.
Solution-processed organo-lead halide perovskite solar cells with deep pinholes in the layer lead to shunt-current leakage devices. Herein, we report a facile method for improving performance of by inserting solution-processed polymer between and hole-transporting layer. The photovoltaic conversion efficiency cell increased 18.1% stability decreased only about 5% during 20 days exposure moisture ambient conditions through incorporation poly(methyl methacrylate) (PMMA) improved devices PMMA...
Abstract Coalescence of [60]fullerenes potentially produces hypothetical nanocarbon assemblies with non-naturally occurring topologies. Since the discovery [60]fullerene in 1985, coalesced oligomers have only been observed as transient species by transmission electron microscopy during an oligomerization process under a high acceleration voltage. Herein, we showcase rational synthesis covalent consisting inherently chiral open-[60]fullerenes. The crystallographic analyses unveiled...
The polymerization of styrene mediated by a polystyryl dithiobenzoate was studied electron spin resonance spectroscopy to determine the concentration intermediate radical produced addition dithiobenzoate. also followed dilatometry estimate growing radical. results showed that fragmentation is fast process with relevant rate constant on order 104 s-1 (at 60 °C) and undergoes cross-termination form 3-arm star chain, thus causing retardation in polymerization. estimated be similar (somewhat...
The bulk synthesis of the [2 + 2] dimer fullerene C60 was achieved by solid-state mechanochemical reaction with KCN use a high-speed vibration milling (HSVM) technique. This took place also potassium salts such as K2CO3 and CH3CO2K, metals Li, Na, K, Mg, Al, Zn, organic bases 4-(dimethylamino)- 4-aminopyridine. Under optimum conditions, afforded only C120 unchanged in ratio about 3:7 (by weight) regardless reagent used. fully characterized IR, UV−vis, 13C NMR, TOF MS spectroscopies, cyclic...
By applying high-pressure H2 to a new fullerene derivative, C63NO2SPh2Py (1), having 13-membered-ring orifice, 100% incorporation of molecule into the cage has been achieved for first time. This result substantiates theoretical calculations indicating that energy barrier required insertion through an orifice in 1 is considerably lower than previously reported derivative with largest among open-cage fullerenes synthesized thus far. Upon matrix-assisted laser desorption/ionization mass...
We report the details of our study to synthesize a new endohedral fullerene, H2@C60, in more than 100 mg quantities by closure 13-membered ring orifice an open-cage fullerene using four-step organic reactions. The previously synthesized incorporating hydrogen 100% yield was reduced 12-membered extrusion sulfur atom at rim orifice, and further into eight-membered reductive coupling two carbonyl groups also orifice. Final completed thermal reaction. Purification H2@C60 accomplished recycle...
Inelastic neutron scattering, far-infrared spectroscopy, and cryogenic nuclear magnetic resonance are used to investigate the quantized rotation ortho–para conversion of single water molecules trapped inside closed fullerene cages. The existence metastable ortho -water is demonstrated, interconversion -and para spin isomers tracked in real time. Our investigation reveals that ground state encapsulated has a lifted degeneracy, associated with symmetry-breaking environment.
Two simple methods to improve tin halide perovskite film structure are introduced, aimed at increasing the power conversion efficiency of lead free solar cells. First, a hot antisolvent treatment (HAT) was found increase coverage and prevent electrical shunting in photovoltaic device. Second, it discovered that annealing under low partial pressure dimethyl sulfoxide vapor increased average crystallite size. The topographical qualities films substantively improved as result combined...
A porous coordination polymer (PCP) has been synthesized employing an organic ligand in which a stable free radical, isoindoline nitroxide, is incorporated. The crystalline PCP possesses one-dimensional channels decorated with the nitroxyl catalytic sites. When O2 gas or air was used as oxidant, this verified to be efficient, recyclable, and widely applicable catalyst for selective oxidation of various alcohols corresponding aldehydes ketones.
The lead halide perovskite semiconductor CH3NH3PbBr3 exhibits an intriguing difference between one-photon and two-photon excited photoluminescence spectra dynamics. It is revealed that the dynamical behaviors are dominated by diffusion of photocarriers from near-surface region to interior single-crystal sample, due high mobilities photoexcited electrons holes.
Nano-carbon materials (carbon nanotubes, graphene, and graphene oxide) have potential application for photovoltaics because of their excellent optical electronic properties. Here, we demonstrate that a single-walled carbon nanotubes/graphene oxide buffer layer greatly improves the photovoltaic performance organo-lead iodide perovskite solar cells. The works as an efficient hole transport/electron blocking layer. conversion efficiency 13.3% was achieved in cell due to complementary properties...
A series of solvent-coordinated tin halide complexes were prepared as impurity-free precursors for perovskites, and their structures determined by single-crystal X-ray diffraction analysis. Using these precursors, the MASnI3 FASnI3, prepared, electronic photophysical properties examined under inert conditions means photoelectron yield spectroscopy well absorption fluorescence spectroscopies. Their valence bands (MASnI3: -5.02 eV; FASnI3: -5.16 eV) are significantly higher than those MAPbI3...
Abstract Dimers of partially oxygen‐bridged triarylamines were designed and synthesized as hole‐transporting materials. X‐ray structural analyses revealed that these compounds form on‐top π‐stacking aggregates in the crystalline state. TRMC measurements showed high levels anisotropic charge transport induced direction π‐stacking. Surprisingly, even vacuum‐deposited amorphous films, retained some face‐on π‐stacking, thus facilitating an out‐of‐plane carrier mobility.
Abstract Triarylboron compounds have attracted much attention, and found wide use as functional materials because of their electron‐accepting properties arising from the vacant p orbitals on boron atoms. In this study, we design synthesize new donor–acceptor triarylboron emitters that show thermally activated delayed fluorescence. These display sky‐blue to green emission high photoluminescence quantum yields 87–100 % in host matrices. Organic light‐emitting diodes using these emitting...
Abstract A water molecule fixed within [60]fullerene is the simplest form of available in meatspace. It was first artificially made by us 2011. Since then, anomalies molecules free from any hydrogen-bonding have been discovered succession. In this account, we summarize research progress past decade aspect synthesis, derivatization, and reactivity fullerenes with inside as well their quantum classical dynamics.