Akito Masuhara

The preparation of fullerene fine crystals with uniform size and shape would permit the control of their specific electronic energy levels and the fabrication of materials with completely new properties. To this end, we have successfully fabricated, for the first time, shape- and size-controlled C60 fine crystals using a reprecipitation method developed in our laboratory. The C60 fine crystals obtained were clearly monodisperse and came in an interesting diversity of shapes such as spherical, ro

We have successfully prepared hybridized microcrystals composed of polydiacetylene microcrystals and silver fine particles by means of the co-reprecipitation method, and investigated their hybridized structure and optical properties. It was revealed experimentally for the first time that the core domain of metal fine particles may interact optoelectronically with the shell layer of polydiacetylene in the hybridized microcrystals to give different electronic states from those of the original comp

We have developed a polymer electrolyte membrane (PEM) material using polymer-coated silica nanoparticles (NPs) by the reversible addition-fragmentation chain-transfer polymerization with particles (RAFT PwP) method. In this paper, we controlled the number density of surface silanol groups on the silica NPs that not only maintain the structure of the surface adsorbed polymers by RAFT PwP but also form fast proton-conducting interface to study the silanol density effect on proton conductivity. Th

Organic-inorganic hybrid lead halide perovskite quantum dots (QDs) have various excellent optical properties, and they have drastically enhanced the field of light-emitting diode (LED) research. However, red-emissive CH₃NH₃ (MA) PbI₃ QDs have worse optical properties compared with those of green-emissive MAPbBr₃ QDs due to their instability under high-moisture and high-temperature conditions. Therefore, it is quite difficult to prepare MAPbI<sub>3</sub

Owing to their excellent photoluminescence (PL) properties in a narrow linewidth below 30 nm and high photoluminescence quantum yield (PLQY), organometal halide perovskite nanocrystals (PeNCs) are promising photonic sources for wide-color gamut displays. However, with a top-down approach, luminescent PeNCs comparable to those prepared through bottom-up synthesis is still a significant subject, including the optimization of milling processes. Herein, we propose a novel and simple ultrasound-assis

Abstract Photophysical and photochemical properties of 1:2 inclusion complexes of C60 and C70 in γ-cyclodextrin (γ-CD) have been studied by laser flash photolysis and steady photolysis methods. The triplet-triplet annihilations of C60/γ-CD and C70/γ-CD are retarded, compared with those of the pristine fullerenes. The rate constant for the fluorescence-quenching of C70/γ-CD by 1,4-diazabicyclo[2.2.2]octane was larger than that of C60/γ-CD, indicating incomplete hindrance by γ-CD due to larger siz

Polymer electrolyte fuel cells (PEFC) are expected as next energy generation systems, and their performance is strongly dependent upon the polymer electrolyte membrane (PEM). We have suggested a new model of PEM with a three-dimensional proton conduction passways structure using the filler method, particularly focused on the functionalization of filler particles. The polymer surface-functionalized silica nanoparticles (NPs) with three different particle sizes were prepared by the reversible addi

Polymer electrolyte membranes (PEMs) are frequently composed of perfluorosulfonic acid polymers (PFSAs) and are used in polymer electrolyte fuel cells (PEFCs). However, PFSAs encounter obstacles such as intense acidity, environmental impact, and high cost. Previous studies have attempted to achieve high proton conductivity in low-acid materials by constructing precise conduction pathways. In addition, nanocellulose is a promising new membrane material for PEFCs with a much lower environmental im

We succeeded in fabrication of monodispersed diarylethene nanoparticles using the reprecipitation method and controlling nanoparticle size in the range of 40 nm to 250 nm by changing concentration of the injected solution and viscosity of good solvent. The obtained nanoparticles exhibited photochromism by alternate irradiation of UV and visible light. In addition, the red-shift of characteristic peak position (around λ = 570 nm) of closed-DAE nanoparticles was observed with increasing nanopartic

Low-acidity polymer electrolyte membranes are essential to polymer electrolyte fuel cells (PEFCs) and water electrolysis systems, both of which are expected to be next-generation energy and hydrogen sources. We developed a new type of high-performance polymer electrolyte membrane (PEM) in which the core particles are precisely electrolyte polymer coated and filled into binder resin. Cellulose nanocrystals (CNCs), which have attracted attention as light, rigid, and sustainable materials, were sel

Abstract We have successfully prepared the hetero-multilayered thin films composed of polydiacetylene microcrystals and gold and/or silver fine particles by means of electrostatic deposition technique, i.e., layer-by-layer deposition method, characterized the morphological structure of the thin films, and evaluated their optical properties. †Deceased. Keywords: Hetero-multilayered thin filmsPolydiacetyleneMicrocrystalsMetal fine particlesLayer-by-layer techniqueElectrostatic deposition Acknowled

The cyclic transformations in shape and crystal structure of C60 microcrystals in dispersion are experimentally demonstrated by changing the dispersion solvent medium, and keeping the dispersion under ultrasonication. The shape of C60 microcrystals was changed from as-grown rod-shape to hexagonal disc-shape, then to belt-shape, and again back to rod-shape. The transformation processes were investigated by means of TEM, XRD and FT-IR measurements. As a results, the present transformation is regar

We have encapsulated diarylethene (DAE) nanocrystals by polystyrene (PS) using soap-free emulsion polymerization. The resulting PS-encapsulated DAE nanocrystals had spherical shape and monodispersed size, and these nanocrystals clearly exhibited photochromism. In addition, PS-encapsulated DAE nanocrystals showed size-dependence of absorption peak positions, although DAE nanocrystals were encapsulated by PS.

The honeycomb-structured film has advantages such as high wettability and high surface area. This structure and properties are suitable for the capacitor electrode. In this study, the electrode structure is controlled by the synthesis of MnO₂ nanoparticles using the breath figure method. The electrode performance was calculated by electrochemical measurements. As a result, the capacitance value was 100.5 F/g at 1 mV s^-1, which was improved 2.7 times as compared with that wi