研究者詳細 - 林　靖彦

論文 - 林　靖彦

分割表示 262 件中 1 - 20 件目／全件表示 >>

Ultrafast dynamics of carrier relaxation determining the quasi-1D and non-1D electronic behaviors in carbon nanostructures

Godai Noyama, Thomas Gauthier, Yusuke Arashida, Yui Iwasaki, Riyo Nagao, Yuri Saida, Nicolas Godin, Gaël Privault, Hiroo Suzuki, Yasuhiko Hayashi, Shota Ono, Roman Bertoni, Masaki Hada

Carbon Trends 20 100510 - 100510 2025年8月

Exploring the structural and optical properties in Cs<inf>3</inf>Fe<inf>2</inf>Cl<inf>9</inf> perovskite through ruthenium doping 査読

Thiri Htun, Hytham Elbohy, Hiroo Suzuki, Kazumasa Horigane, Chiyu Nakano, Takeshi Nishikawa, Aung Ko Ko Kyaw, Yasuhiko Hayashi

Journal of Materials Science: Materials in Electronics 36 ( 5 ) 2025年2月

担当区分：最終著者,　責任著者掲載種別：研究論文（学術雑誌）

Lead-free inorganic perovskites, such as Cs3Fe2Cl9, have emerged as promising alternatives to address the challenges of toxicity and instability issues. However, the wide bandgap of Cs3Fe2Cl9 limits its applicability in some applications. In this study, we systematically investigate the influence of ruthenium (Ru) doping on the structural and optical properties of Cs3Fe2Cl9 perovskite with the various doping concentrations (0%, 5%, 20%, 50%, 70% and 100%). Comprehensive characterization was performed through X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV–Vis spectroscopy, and scanning electron microscopy (SEM). Structural analysis revealed a phase transition from Cs3Fe2Cl9 (hexagonal structure) at 0% Ru doping to Cs2RuCl6 (cubic structure) at 100% Ru doping. Notably, ruthenium was successfully replaced into the pristine Cs3Fe2Cl9 perovskite due to the similar ionic radii of Fe and Ru. Optical measurements confirmed a significant bandgap reduction from 2.29 eV for pristine Cs3Fe2Cl9 to 1.79 eV at 100% Ru doping, correlating with the formation of single crystals. This tunable bandgap highlights the potential of Ru-doped Cs3Fe2Cl9 for next-generation optoelectronic applications, such as photovoltaics and photodetectors.

DOI： 10.1007/s10854-025-14382-1

Scopus

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Enhanced capacity of aluminum-ion batteries by adjusting the average pore size of the porous carbon cathode 査読

Yifeng Chen, Hiroo Suzuki, Shu Fukumoto, Chiyu Nakano, Takeshi Nishikawa, Shigeyuki Umezawa, Yasuhiko Hayashi

Journal of Materials Chemistry A 13 ( 11 ) 8052 - 8058 2025年2月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry (RSC)

Porous carbon materials exhibit unique performance as cathodes for aluminum-ion batteries (AIBs), with capacity primarily influenced by average pore size, while the effect of specific surface area is relatively limited.

DOI： 10.1039/d4ta08671f

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Optical bandgap tuning in SnO2–MoS2 nanocomposites: manipulating the mass of SnO2 and MoS2 using sonochemical solution mixing 査読

Chinkhai Ong, Weng Nam Lee, Yee Seng Tan, Patrik Ohberg, Yasuhiko Hayashi, Takeshi Nishikawa, Yuenkiat Yap

Journal of Materials Science: Materials in Electronics 36 ( 1 ) 2024年12月

掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

Abstract

This study investigates controlled optical bandgap tuning through precise adjustment of the SnO₂ and MoS₂ mass in nanocomposites. A sonochemical solution mixing method, coupled with bath sonication, is employed for the preparation of SnO₂–MoS₂ nanocomposite. This approach allows for comprehensive characterization using UV–Vis FTIR, XRD, EDX, Raman spectroscopies, and FESEM, providing insights into morphology, chemical, and optical properties. Increasing the SnO₂ mass leads to a linear decrease in the optical bandgap energy, from 3.0 to 1.7 eV. Similarly, increasing the MoS₂ mass also results in a decrease in the optical bandgap energy, with a limitation of around 2.01 eV. This work demonstrates superior control over optical bandgap by manipulating the SnO₂ mass compared to MoS₂, highlighting the complexities introduced by MoS₂ 2D nanosheets during sonication. These findings hold significant value for optoelectronic applications, emphasizing enhanced control of optical bandgap through systematic mass manipulation.

DOI： 10.1007/s10854-024-14061-7

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その他リンク： https://link.springer.com/article/10.1007/s10854-024-14061-7/fulltext.html

Enhanced piezo-response of mixed-cation copper perovskites with Cl/Br halide engineering 査読

Amr Elattar, Christopher Munoz, Libor Kobera, Andrii Mahun, Jiri Brus, Mohammed Jasim Uddin, Yasuhiko Hayashi, Okenwa Okoli, Tarik Dickens

Materials Advances 5 ( 22 ) 8953 - 8960 2024年10月

Photoinduced dynamics during electronic transfer from narrow to wide bandgap layers in one-dimensional heterostructured materials 査読

Yuri Saida, Thomas Gauthier, Hiroo Suzuki, Satoshi Ohmura, Ryo Shikata, Yui Iwasaki, Godai Noyama, Misaki Kishibuchi, Yuichiro Tanaka, Wataru Yajima, Nicolas Godin, Gaël Privault, Tomoharu Tokunaga, Shota Ono, Shin-ya Koshihara, Kenji Tsuruta, Yasuhiko Hayashi, Roman Bertoni, Masaki Hada

Nature Communications 15 ( 1 ) 2024年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

Abstract

Electron transfer is a fundamental energy conversion process widely present in synthetic, industrial, and natural systems. Understanding the electron transfer process is important to exploit the uniqueness of the low-dimensional van der Waals (vdW) heterostructures because interlayer electron transfer produces the function of this class of material. Here, we show the occurrence of an electron transfer process in one-dimensional layer-stacking of carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs). This observation makes use of femtosecond broadband optical spectroscopy, ultrafast time-resolved electron diffraction, and first-principles theoretical calculations. These results reveal that near-ultraviolet photoexcitation induces an electron transfer from the conduction bands of CNT to BNNT layers via electronic decay channels. This physical process subsequently generates radial phonons in the one-dimensional vdW heterostructure material. The gathered insights unveil the fundamentals physics of interfacial interactions in low dimensional vdW heterostructures and their photoinduced dynamics, pushing their limits for photoactive multifunctional applications.

DOI： 10.1038/s41467-024-48880-3

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その他リンク： https://www.nature.com/articles/s41467-024-48880-3

Phenolphthalein: A Potent Small-Molecule Additive for High-Performance and Ambient-Air-Stable FAPbI₃ Perovskite Solar Cells 査読

Hytham Elbohy, Hiroo Suzuki, Takeshi Nishikawa, Aung Ko Ko Kyaw, Yasuhiko Hayashi

ACS Applied Energy Materials 2024年3月

N‐DMBI Doping of Carbon Nanotube Yarns for Achieving High n‐Type Thermoelectric Power Factor and Figure of Merit 査読

Hiroo Suzuki, Jun Kametaka, Shinya Nakahori, Yuichiro Tanaka, Mizuki Iwahara, Haolu Lin, Sergei Manzhos, Aung Ko Ko Kyaw, Takeshi Nishikawa, Yasuhiko Hayashi

Small Methods 8 2301387 2024年3月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Wiley

Abstract

The application of carbon nanotube (CNT) yarns as thermoelectric materials for harvesting energy from low‐grade waste heat including that generated by the human body, is attracting considerable attention. However, the lack of efficient n‐type CNT yarns hinders their practical implementation in thermoelectric devices. This study reports efficient n‐doping of CNT yarns, employing 4‐(1, 3‐dimethyl‐2, 3‐dihydro‐1H‐benzimidazole‐2‐yl) phenyl) dimethylamine (N‐DMBI) in alternative to conventional n‐dopants, with o‐dichlorobenzene emerging as the optimal solvent. The small molecular size of N‐DMBI enables highly efficient doping within a remarkably short duration (10 s) while ensuring prolonged stability in air and at high temperature (150 °C). Furthermore, Joule annealing of the yarns significantly improves the n‐doping efficiency. Consequently, thermoelectric power factors (PFs) of 2800, 2390, and 1534 µW m⁻¹ K⁻² are achieved at 200, 150, and 30 °C, respectively. The intercalation of N‐DMBI molecules significantly suppresses the thermal conductivity, resulting in the high figure of merit (ZT) of 1.69×10⁻² at 100 °C. Additionally, a π‐type thermoelectric module is successfully demonstrated incorporating both p‐ and n‐doped CNT yarns. This study offers an efficient doping strategy for achieving CNT yarns with high thermoelectric performance, contributing to the realization of lightweight and mechanically flexible CNT‐based thermoelectric devices.

DOI： 10.1002/smtd.202301387

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Influence of Dilution Upon the Ultraviolet-Visible Peak Absorbance and Optical Bandgap Estimation of Tin(IV) Oxide and Tin(IV) Oxide-Molybdenum(IV) Sulfide Solutions 査読

Chin Khai Ong, Weng Nam Lee, Mohammad Khalid, Muhammad Amirul Aizat Mohd Abdah, Patrik Ohberg, Ling Hong Lim, Yasuhiko Hayashi, Takeshi Nishikawa, Yuenkiat Yap

Analytical Letters 58 ( 2 ) 196 - 212 2024年2月

Lead-free iron-doped Cs₃Bi₂Br₉ perovskite with tunable properties 査読

Thiri Htun, Amr Elattar, Hytham Elbohy, Kosei Tsutsumi, Kazumasa Horigane, Chiyu Nakano, Xiaoyu Gu, Hiroo Suzuki, Takeshi Nishikawa, Aung Ko Ko Kyaw, Yasuhiko Hayashi

RSC Advances 14 ( 32 ) 23177 - 23183 2024年

担当区分：最終著者,　責任著者掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry (RSC)

The bandgap of lead-free, non-toxic Cs₃Bi₂Br₉ perovskite material is reduced from 2.54 eV to 1.78 eV by changing the crystal structure to Cs₃Bi₂₋_xFe_xBr₉, Cs₂Bi₁₋_xFe_xBr₅, and CsFeBr₄, depending on the varying Fe doping concentrations.

DOI： 10.1039/d4ra04062g

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Benzophenone: A Small Molecule Additive for Enhanced Performance and Stability of Inverted Perovskite Solar Cells. 査読国際誌

Hytham Elbohy, Hiroo Suzuki, Takeshi Nishikawa, Thiri Htun, Kosei Tsutsumi, Chiyu Nakano, Aung Ko Ko Kyaw, Yasuhiko Hayashi

ACS applied materials & interfaces 15 ( 38 ) 45177 - 45189 2023年9月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, we investigated the impact of benzophenone (BP), a small molecule additive, on the performance and stability of inverted perovskite solar cells (PSCs). Specifically, we introduced BP into the perovskite precursor solution of FAPbI3 to fabricate PSCs with an ITO/PEDOT:PSS/BP:FAPbI3/PCBM/C60/PCB/Ag architecture. The incorporation of BP with an optimum concentration of 2 mg mL-1 significantly enhanced the power conversion efficiency (PCE) of the inverted PSC from 13.12 to 18.84% with negligible hysteresis. Notably, the BP-based PSCs retained ∼90% of their initial PCE after being stored in ambient air with 30% relative humidity at 25 °C for 700 h. In contrast, control devices showed rapid degradation, retaining only 30% of their initial value within 300 h under the same conditions. We attributed the superior performance and stability of the BP-based PSCs to the grain boundary passivation of the perovskite film. The improvement was mainly attributed to the intermolecular interaction between the O-donor Lewis base BP material and both Pb2+ and FA+ in FAPbI3. This effectively suppresses trap-assisted recombination and promotes the conversion of the δ-phase to photoactive and stable α-phase FAPbI3. Overall, our findings suggest that BP is a promising additive for improving the performance and stability of inverted PSCs.

DOI： 10.1021/acsami.3c09835

PubMed

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Intermediate State between MoSe₂ and Janus MoSeS during Atomic Substitution Process 査読

Hiroo Suzuki, Yijun Liu, Masaaki Misawa, Chiyu Nakano, Yingzhe Wang, Ryo Nakano, Kentaro Ishimura, Kenji Tsuruta, Yasuhiko Hayashi

Nano Letters 23 ( 10 ) 4533 - 4540 2023年5月

Self-Limiting Growth of Monolayer Tungsten Disulfide Nanoribbons on Tungsten Oxide Nanowires 査読

Hiroo Suzuki, Misaki Kishibuchi, Masaaki Misawa, Kazuma Shimogami, Soya Ochiai, Takahiro Kokura, Yijun Liu, Ryoki Hashimoto, Zheng Liu, Kenji Tsuruta, Yasumitsu Miyata, Yasuhiko Hayashi

ACS Nano 17 ( 10 ) 9455 - 9467 2023年5月

Integration of Wireless Power Transfer Technology With Hierarchical Multiwalled Carbon Nanotubes-Polydimethylsiloxane Piezo-Responsive Pressure Sensor for Remote Force Measurement 査読

Saman Azhari, Kouki Kimizuka, Gábor Méhes, Yuki Usami, Yasuhiko Hayashi, Hirofumi Tanaka, Takeo Miyake

IEEE Sensors Journal 23 ( 7 ) 7902 - 7909 2023年4月

Dispersion stability of tin(IV) oxide nanoparticles in polar solvents and water aided by ultrasonication 査読

Chinkhai Ong, Wengnam Lee, Linghong Lim, Wuyi Chong, Jingwen Chew, Yasuhiko Hayashi, Takeshi Nishikawa, Patrik Öhberg, Harith Ahmad, Yuenkiat Yap

Japanese Journal of Applied Physics 62 ( 3 ) 035002 - 035002 2023年3月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

Dispersion stability of tin(IV) oxide nanoparticles dispersed in N-Methy-2-Pyrrolidone (NMP), dimethylformamide (DMF) and distilled water assisted by ultrasonication was investigated, aiming to identify a suitable liquid medium to effectively disperse tin(IV) oxide for many useful applications. The dispersions’ stability was characterized using field emission scanning electron microscopy, ultraviolet–visible spectroscopy and Zeta potential. The results show that distilled water has the highest stability with optimum sonication of 1 h. NMP shows better stability and consistency than DMF at different sonication timings. Good agreement between ultraviolet–visible absorbance and Zeta potentials shows that both distilled water and NMP are good mediums to produce highly stable tin(V) oxide dispersion.

DOI： 10.35848/1347-4065/acc0b5

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その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/acc0b5/pdf

Zinc‐Based Metal–Organic Frameworks for High‐Performance Supercapacitor Electrodes: Mechanism Underlying Pore Generation 査読

Shigeyuki Umezawa, Takashi Douura, Koji Yoshikawa, Daisuke Tanaka, Vlad Stolojan, S. Ravi P. Silva, Mika Yoneda, Kazuma Gotoh, Yasuhiko Hayashi

ENERGY & ENVIRONMENTAL MATERIALS 2023年3月

Tin(IV) Oxide as a Saturable Absorber for Mode-Locking of Fiber Laser 査読

C. Ong, Y. Yap, W. Chong, J. Chew, W. Lee, L. Lim, Y. Hayashi, T. Nishikawa, P. Ohberg, H. Ahmad

Optica Advanced Photonics Congress 2022 2022年12月

Mixed-halide copper-based perovskite R2Cu(Cl/Br)(4) with different organic cations for reversible thermochromism 査読

Amr Elattar, Kosei Tsutsumi, Hiroo Suzuki, Takeshi Nishikawa, Aung Ko Ko Kyaw, Yasuhiko Hayashi

NEW JOURNAL OF CHEMISTRY 46 ( 45 ) 21737 - 21745 2022年11月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ROYAL SOC CHEMISTRY

Two-dimensional (2D) hybrid perovskites have exhibited multiple features owing to their multiple quantum well structure. Here, we show the synthesis and characterization of 2D mixed-halide Cu-based perovskite crystals, R2Cu(Cl/Br)(4), with three different alkyl chains, where R is methyl, butyl, or hexyl ammonium cations. Exfoliated perovskite flakes exhibit reversible thermochromism with changes in color darkness with temperature variation. Differential scanning calorimetry and temperature-dependent X-ray diffraction measurements reveal that the thermochromic behavior mechanism of R2Cu(Cl/Br)(4) depends on the nature of the alkyl chain.

DOI： 10.1039/d2nj04693h

Web of Science

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Characteristics of Vertical Ga2O3 Schottky Junctions with the Interfacial Hexagonal Boron Nitride Film 査読

Venkata Krishna Rao Rama, Ajinkya K. Ranade, Pradeep Desai, Bhagyashri Todankar, Golap Kalita, Hiroo Suzuki, Masaki Tanemura, Yasuhiko Hayashi

ACS Omega 7 ( 30 ) 26021 - 26028 2022年8月

Copper-incorporation for polytypism and bandgap engineering of MAPbBr3 perovskite thin films with enhanced near-Infrared photocurrent-response 査読

Amr Elattar, Jiban Kangsabanik, Kodai Nakao, Kosei Tsutsumi, Hiroo Suzuki, Takeshi Nishikawa, Kristian S. Thygesen, Yasuhiko Hayashi

Materials Chemistry Frontiers 6 ( 18 ) 2690 - 2702 2022年8月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry ({RSC})

Formation of secondary phase polytypes through incorporation of copper into MAPbBr₃ perovskite yields bandgap reduction with generation of near-IR photocarriers.

DOI： 10.1039/D2QM00491G

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