Hokkaido University · Engineering
Professor Naoto Koshizaki's research lab specializes in the design, synthesis, and application of advanced nanomaterials using pulsed laser deposition (PLD) and laser-based processing techniques. The lab focuses on creating hierarchical nanostructures such as TiO₂, Co₃O₄, ZnO, and carbon quantum dots with tailored optical, surface, and catalytic properties. Key research directions include the development of stimuli-responsive surfaces—particularly superhydrophilic and switchable wettability materials—alongside applications in sensing, gas detection, and optoelectronics.
Figures are computed from collected data and may differ slightly.
A simple approach to prepare carbon quantum dots is presented in this communication by laser rapid passivation of nano carbon particles in ordinary organic solvent. The as-prepared carbon dots exhibited visible, tunable and stable photoluminescence (PL). XPS analysis showed that the increased oxygen concentration might be concerned with the origin of PL.
A hierarchical TiO(2) ordered hemispherical particle array with hexagonal-non-close-packed (hncp) tops is prepared by pulsed laser deposition (PLD) using a polystyrene colloidal monolayer as a template. Compared with conventional lithography, the route presented has the advantage of low cost for producing hncp nanostructured arrays. This hierarchical particle array exhibits excellent superhydrophilicity with a water contact angle of 0 degrees without further UV irradiation. The superhydrophilic
Ordered Co3O4 hierarchical nanorod arrays have been fabricated employing pulsed laser deposition (PLD) on polystyrene colloid spheres followed by an annealing process in air. The surface roughness and chemical composition were controlled successfully by adjusting the oxygen pressure during the PLD process and post-annealing temperature, respectively. The as-prepared Co3O4nanorod arrays had superior superhydrophilicity without UV irradiation, which was attributed to the improved roughness related
Size-tailored ZnO submicrometer spheres are synthesized based on bottom-up laser processing. A heating–melting–evaporating mechanism is responsible for the formation of submicrometer-scale spherical particles. The size-related optical extinction and selective aniline trapping on ZnO submicrometer spheres indicate that they are potential candidates for optical and gas-sensing applications. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents
Abstract Periodic TiO 2 nanorod arrays with hexagonal nonclose‐packed (hncp) arrangements are synthesized by pulsed laser deposition (PLD) using polystyrene colloidal monolayers as templates and with subsequent annealing in air. The hncp‐array formation is governed by in situ volume shrinkage of amorphous TiO 2 nanorods in the crystallizing process during annealing. The array periodicity can easily be tuned by different sphere sizes of the colloidal template, whereas the distance between neighbo
Abstract Colloidal Au‐amplified surface plasmon resonance (SPR), like traditional SPR, is typically used to detect binding events on a thin noble metal film. The two major concerns in developing colloidal Au‐amplified SPR lie in 1) the instability, manifested as a change in morphology following immersion in organic solvents and aqueous solutions, and 2) the uncontrollable interparticle distance, determining probe spacing and inducing steric hindrance between neighboring probe molecules. This may
We achieved the vertically aligned and ordered hematite hierarchical columnar arrays using pulsed laser deposition (PLD) with polystyrene (PS) colloid spheres as templates. Crystallized hematite hexagonal-close-packed columnar arrays are fabricated at room temperature and can be transformed to hexagonal-non-close-packed columnar arrays at an annealing temperature of 450 °C. The hierarchical columns consist of assembled nanoplates or nanoparticles, depending on the oxygen pressures during the PLD
A new one-step approach was developed to synthesize bimetallic alloy submicrometer spheres, which are immiscible under equilibrium, using AuCo as a model system. Uniform, single-phase AuCo alloy submicrometer particles (∼230 nm) with a well-defined spherical morphology were successfully formed via pulsed laser irradiation of Au and Co-oxides nanoparticles dispersed in ethanol and characterized with a combination of electron microscopy, diffraction and magnetization measurements.
The development of a general method to fabricate spherical semiconductor and metal particles advances their promising electrical, optical, magnetic, plasmonic, thermoelectric, and optoelectric applications. Herein, by using CuO as an example, we systematically demonstrate a general bottom-up laser processing technique for the synthesis of submicrometer semiconductor and metal colloidal spheres, in which the unique selective pulsed heating assures the formation of spherical particles. Importantly
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