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3,044 results on '"Ozaki, Yukihiro"'

26. Introduction

Author

Ozaki, Yukihiro, Huck, Christian, Ozaki, Yukihiro, editor, Huck, Christian, editor, Tsuchikawa, Satoru, editor, and Engelsen, Søren Balling, editor

Published
2021
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39. A green approach to nanoplastic detection: SERS with untreated filter paper for polystyrene nanoplastics.

Author

Chaisrikhwun, Boonphop, Balani, Mary Jane Dacillo, Ekgasit, Sanong, Xie, Yunfei, Ozaki, Yukihiro, and Pienpinijtham, Prompong

Subjects
SERS spectroscopy, FILTER paper, SUSTAINABILITY, SILVER nanoparticles, NANOPARTICLES
Abstract

Plastic pollution at the nanoscale continues to pose adverse effects on environmental sustainability and human health. However, the detection of nanoplastics (NPLs) remains challenging due to limitations in methodology and instrumentation. Herein, a "green approach" for surface-enhanced Raman spectroscopy (SERS) was exploited to detect polystyrene nanospheres (PSNSs) in water, employing untreated filter paper and a simple syringe-filtration set-up. This SERS protocol not only enabled the filtration of nano-sized PSNSs, which are smaller than the pore size of the ordinary filter paper, but also offered SERS enhancement by utilizing quasi-spherical-shaped silver nanoparticles (AgNPs) as the SERS-active substrate. The filtering of NPLs was accomplished by adding an aggregating agent to the nanoparticle mixture, which caused the aggregation of NPLs and AgNPs, resulting in a larger cluster and more hot spots for SERS detection. The optimal aggregating agent and its concentration, as well as the volume ratio between the AgNPs and NPLs, were also optimized. This SERS method successfully detected and quantified PSNSs of various sizes (i.e., 100, 300, 460, 600, and 800 nm) down to a limit of detection (LOD) of about 0.31 μg mL−1. The method was also validated against the presence of several interferents (i.e., salts, sugars, amino acids, and surfactants) and was proven practical, as evidenced by the detection of 800nm PSNSs in drinking and tap water (LODs of 1.47 and 1.55 μg mL−1, respectively). [ABSTRACT FROM AUTHOR]

Published
2024
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41. Macroscale TiO2 Microspherical Arrays with Multiple Synergistic Effect for Highly Sensitive Surface‐Enhanced Raman Scattering.

Author

Li, Junfang, Xie, Qinhui, Li, Junbo, Sun, Lei, Xie, Yunfei, Ozaki, Yukihiro, and Ji, Wei

Subjects
SERS spectroscopy, SEMICONDUCTOR materials, CHEMICAL stability, BIOCHEMICAL substrates, SUBSTRATES (Materials science)
Abstract

Semiconductor materials represent an ideal choice for designing surface‐enhanced Raman scattering (SERS)‐based sensors due to their superior thermal and chemical stability compared to conventional metal materials. However, current SERS‐active semiconductor substrates have limitations such as low detection sensitivity and often complicated preparation steps, which restrict their real‐life applications. In this work, for the first time the feasibility of large‐area fabricating SERS‐active semiconductor substrates based on screen‐printing of micron‐sized TiO2 ink synthesized through a simple flame thermal‐assisted method is demonstrated. The resultant TiO2 microspherical arrays (MSAs) exhibit extraordinary SERS sensitivity with an enhancement factor of 3.28 × 107, which represents one of the highest sensitivity and are the easiest strategy among the reported SERS‐active semiconductor substrates. Both experiments and simulations rationalize the observed enhancement factor and propose that multiple synergistic resonances, including Mie resonance, charge‐transfer resonance, and molecular resonance significantly boost the performance of semiconductor substrates. Dye‐modified TiO2 MSAs are further exploited as the sensing platform for the development of a ratiometric SERS sensor, enabling the highly sensitive, selective, low cost, and stable detection of Hg2+ ions. This study opens up new possibilities for preparing a large‐scale SERS‐active semiconductor array, ultimately advancing the fields of semiconductor‐based SERS sensing technology. [ABSTRACT FROM AUTHOR]

Published
2024
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42. Single-Molecule Surface-Enhanced Raman Scattering Spectrum of Non-Resonant Aromatic Amine Showing Raman Forbidden Bands

Author

Yamamoto, Yuko S., Kayano, Yuya, Ozaki, Yukihiro, Zhang, Zhenglong, Kozu, Tomomi, Itoh, Tamitake, and Nakanishi, Shunsuke

Subjects
Physics - Chemical Physics
Abstract

We present the experimentally obtained single-molecule (SM) surface-enhanced Raman scattering (SERS) spectrum of 4-aminibenzenethiol (4-ABT), also known as para-aminothiophenol (PATP). Measured at a 4-ABT concentration of 8 * 10^-10 M, the spectra show Raman forbidden modes. The SM-SERS spectrum of 4-ABT obtained using a non-resonant visible laser is different from the previously reported SERS spectra of 4-ABT, and could not be reconstructed using quantum mechanical calculations. Careful classical assignments (not based on quantum-mechanical calculations) are reported, and indicate that differences in the reported spectra of 4-ABT are mainly due to the appearance of Raman forbidden bands. The presence of Raman forbidden bands can be explained by the charge-transfer (CT) effect of 4-ABT adsorbed on the silver nanostructures, indicating a breakdown of Raman selection rules at the SERS hotspot.

Published
2016

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