Kyoto University · Materials Science
Professor Masanori Sakamoto's research lab specializes in the design and characterization of advanced nanomaterials for sustainable energy conversion, with a strong focus on plasmonics, photocatalysis, and carrier dynamics in semiconductor heterostructures. The lab explores mechanisms of hot-carrier generation and transfer—particularly in plasmonic nanocrystals such as CdS/CuS and CdS/Cu₇S₄—enabling efficient utilization of visible and infrared light for artificial photosynthesis and hydrogen evolution. Using advanced spectroscopic techniques like time-resolved infrared spectroscopy and flash photolysis, the group investigates ultrafast charge transfer processes and interfacial phenomena in complex nanostructures. Their work also extends to functional nanocomposites, including bimetallic nanoparticle-polymer films, for tunable optical and electronic applications.
Figures are computed from collected data and may differ slightly.
Localized surface plasmon resonance (LSPR)-induced hot-carrier transfer is a key mechanism for achieving artificial photosynthesis using the whole solar spectrum, even including the infrared (IR) region. In contrast to the explosive development of photocatalysts based on the plasmon-induced hot electron transfer, the hole transfer system is still quite immature regardless of its importance, because the mechanism of plasmon-induced hole transfer has remained unclear. Herein, we elucidate LSPR-ind
Infrared (IR) light represents an untapped energy source accounting for almost half of all solar energy. Thus, there is a need to develop systems to convert IR light to fuel and make full use of this plentiful resource. Herein, we report photocatalytic H<sub>2</sub> evolution driven by near- to shortwave-IR light (up to 2500 nm) irradiation, based on novel CdS/Cu<sub>7</sub>S<sub>4</sub> heterostructured nanocrystals. The apparent quantum yield reached 3.8% at 1100 nm, which exceeds the highest
Abstract Using a four‐electrode cell and a new electronic system for direct detection of the frequency differences specturm of solution impedance, the complex dielectric constant of calf thymus DNA ( M r = 4 × 10 6 ) in aqueous NaCl at 10°C is measured at frequencies ranging from 0.2 Hz to 30 kHz. The DNA concentrations are C p = 0.01% and 0.05%, and the NaCl concentrations are varied from C s = 10 −4 M to 10 −3 M . A single relaxation regions is found in this frequency range, the relaxation fre
Abstract Metal nanoparticle (NP)–polymer nanocomposite thin films are attractive for applications in various devices. Since bimetallic NPs provide additional opportunities for tuning the physical properties of the NP components, the development of bimetallic NP nanocomposite thin films should lead to further enhancements of various applications. Au/Cu bimetallic NPs are fabricated in a poly(vinyl alcohol) (PVA) film using a photochemical process. Interestingly, different sizes and shapes of Au/C
Controlling the carrier dynamics in a semiconductor nanoparticulate photocatalyst is the key to developing catalytic activity. Generally, type I band alignment is unsuitable for photocatalysts because the photoinduced carriers accumulate in the narrow bandgap semiconductor. To avoid the termination of reactions and/or photocorrosion of materials caused by carrier accumulation, it is common to employ type II band alignment for photoenergy conversion systems instead of type I. However, CdS/ZnS cor
The absorption spectrum of benzophenone ketyl radicals in the D1 excited state (BPH•(D1)), generated by hydrogen abstraction of triplet benzophenone from cyclohexane as a solvent and the sequential excitation of the benzophenone ketyl radical in the ground state (BPH•(D0)), was directly observed using nanosecond−picosecond two-color two-laser flash photolysis. The whole spectral shape of BPH•(D1) with peaks at 350 and 480 nm was detected for the first time. The absorption spectra and lifetimes w
Infrared-light-induced carrier transfer is a key technology for 'invisible' optical devices for information communication systems and energy devices. However, clear and colourless photo-induced carrier transfer has not yet been demonstrated in the field of photochemistry, to the best of our knowledge. Here, we resolve this problem by employing short-wavelength-infrared (1400-4000 nm) localized surface plasmon resonance-induced electron injection from indium tin oxide nanocrystals to transparent
The "ligand effect" can be used as a novel strategy for enhancing the catalytic properties of metal clusters. Herein, we report the ligand effect of porphyrin derivatives on gold clusters (AuCs, size <2 nm) and gold nanoparticles (AuNPs, size >2 nm) in the electrochemical hydrogen evolution reaction (HER) at pH 6.7. The current density of porphyrin face-coordinated AuCs at -0.4 V <i>vs.</i> reversible hydrogen electrode (RHE) was 460% higher than that of phenylethanethiol-protected AuCs. X-ray p
Noble metal clusters of sizes comparable to the Fermi wavelength are known to exhibit molecule-like transitions owing to the discretion of the density of states. In the present article, the important factors influencing the reactivity of excited gold (Au) clusters are examined from the viewpoint of molecular photochemistry. The investigation of the differently sized Au clusters embedded in a polymer film using single-molecule fluorescence spectroscopy facilitates the further understanding of the
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