Papers - IKEDA Shigeru
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Flux-Assisted Syntheses of Calcium Titanate Powders Codoped with Aluminum, Scandium, and Magnesium for Efficient Photocatalytic Overall Water Splitting Reviewed International journal
Kaori Takagi, Tomoya Ota, Kota Kato, Ryota Tomizawa, Tomoya Nagano, Koji Hayashi, Akira Yamakata, Yoshitaro Nose, Nobuya Machida, Shigeru Ikeda
ACS Applied Energy Materials 8 ( 16 ) 11961 - 11969 2025.8
Joint Work
Authorship：Last author, Corresponding author
Calcium titanate (CaTiO3) has attracted interest as a photocatalyst for overall water splitting, but its efficiency remains limited. In this study, CaTiO3 powders codoped with aluminum (Al3+), scandium (Sc3+), and magnesium (Mg2+) cations were synthesized via a flux-mediated method. XRD and Raman analyses confirmed the formation of single-phase perovskite structures with successful dopant incorporation at the B-site (Ti4+). Appreciable particle growth was observed in the Al3+-doped sample. Codoping with Sc3+ significantly reduced particle size but also lowered crystallinity, which hindered photocatalytic activity. Further codoping with Mg2+ effectively suppressed the formation of deep-level defects. As a result, the CaTiO3 powder codoped with Al3+, Sc3+, and Mg2+ (CaTiO3:Al,Sc,Mg) exhibited the highest photocatalytic activity, achieving an apparent quantum yield (AQY) of 73.8% (at 310 nm). Durability tests showed that degradation occurred primarily on the loaded cocatalysts, not the CaTiO3 itself. Transient absorption measurements revealed enhanced carrier reactivity due to trap state modulation and improved lifetimes in the CaTiO3:Al,Sc,Mg sample. Band alignment studies indicated that CaTiO3 has a more negative conduction band minimum than that of strontium titanate (SrTiO3). These findings demonstrate that strategic doping significantly enhances the photocatalytic properties of CaTiO3 for various reactions.
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Enhanced photoelectrochemical performance of Zr-doped BiVO4 photoanode deposited by co-sputtering
Shukur Gofurov, Daryl Ide, Lingga Ghufira Oktariza, Muhammad M. Islam, Shigeru Ikeda, Takeaki Sakurai
Thin Solid Films 2025.6
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Visible-light-driven hydrogen evolution using calcium titanate codoped with aluminium, antimony, magnesium, and rhodium, loaded with a platinum (core)–chromia (shell) cocatalyst Reviewed International journal
Tomoya Ota, Ryota Tomizawa, Tomoya Nagano, Koji Hayashi, Shigeru Ikeda
Materials Advances 6 3455 - 3459 2025.4
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Ferrocene-Based Organic Semiconductors: Evaluating Intermolecular Transfer Integrals and Transistor Properties
Hiroki Sano, Muneyuki Naito, Kosuke Katagiri, Shigeru Ikeda, Atsushi Kimoto, Tomofumi Kadoya
ACS Applied Electronic Materials 2024.11
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Characterization of the electronic structure of sputter-deposited Mo-doped BiVO4 thin-film photoanodes Reviewed
L. Oktariza, Y. Sato, S. Gofurov, K. Ozawa, M. M. Islam, S. Ikeda, T. Sakurai
Jpn. J. Appl. Phys. 63 02SP41 2024.1
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Shigeru Ikeda, Riku Okamoto, Akira Kimura, Yuhi Nakayasu, Akira Yamakata, Ryota Tomizawa, Taizo Masuda, Koichiro Nakatani
Sustainable Energy & Fuels 8 202 - 209 2023.11
Authorship：Lead author, Corresponding author Publisher：Royal Society of Chemistry (RSC)
A high photocatalytic performance for overall water splitting was demonstrated over a photocatalyst based on a magnesium and scandium co-doped strontium titanate particle composed of a cubic shape having a nanosized step structure on the edge of the particle.
DOI： 10.1039/d3se01408h
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Crystalline-face-dependent photoelectrochemical properties of single crystalline CuGaSe2 photocathodes for hydrogen evolution under sunlight radiation Invited Reviewed
Shigeru Ikeda, Wakaba Fujita, Ryoji Katsube, Yoshitaro Nose, Hajime Suzuki, Ryu Abe, Kenji Yoshino
Electrochimica Acta 454 142384 - 142384 2023.4
Authorship：Lead author, Corresponding author Publisher：Elsevier BV
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Crystalline phase control of BiVO4 thin films using RF sputtering Reviewed
N. Uezono, J. Liu, P. A. Sachin, M. M. Islam, S. Ikeda, T. Sakurai
Jpn. J. Appl. Phys. 62 SK1001 2023.3
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Effect of sodium incorporation on CuIn(S,Se)2 thin films fabricated by aqueous spray deposition and their photovoltaic properties Reviewed International coauthorship
W. Septina, Y. Kawasaki, T. Harada, S. Ikeda
J. Cryst. Growth 602 ( 14 ) 126975 2023.1
Authorship：Last author
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Tooru Tanaka, Ryusuke Tsutsumi, Tomohiro Yoshinaga, Takaki Sonoyama, Katsuhiko Saito, Qixin Guo, Shigeru Ikeda
RSC Advances 13 575 - 583 2022.12
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Process accumulated 8% efficient Cu2ZnSnS4-BiVO4 tandem cell for solar hydrogen evolution with the dynamic balance of solar energy storage and conversion Reviewed International coauthorship
H. Cai, G. Xiao, W. Zhao, X. Wu, Y. Hu, H. Ni, S. Ikeda, Y. H. Ng
Adv. Sci. 10 ( 5 ) 2205726 2022.12
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Research on the Influence of the Interfacial Properties Between a Cu3BiS3 Film and an InxCd1-xS Buffer Layer for Photoelectrochemical Water Splitting Reviewed International coauthorship
Xiaomin Wu, Weidong Zhao, Yucheng Hu, Guohong Xiao, Huanyang Ni, Shigeru Ikeda, Yunhau Ng, Feng Jiang
ADVANCED SCIENCE 9 ( 33 ) 2022.11
Publisher：WILEY
The ternary compound photovoltaic semiconductor Cu3BiS3 thin film-based photoelectrode demonstrates a quite promising potential for photoelectrochemical hydrogen evolution. The presented high onset potential of 0.9 V-RHE attracts much attention and shows that the Cu3BiS3 thin films are quite good as an efficient solar water splitting photoelectrode. However, the CdS buffer does not fit the Cu3BiS3 thin film: the conduction band offset between CdS and Cu3BiS3 reaches 0.7 eV, and such a high conduction band offset (CBO) significantly increases the interfacial recombination ratio and is the main reason for the relatively low photocurrent of the Cu3BiS3/CdS photoelectrode. In this study, the InxCd1-xS buffer layer is found to be significantly lowered the CBO of CBS/buffer and that the In incorporation ratio of the buffer influences the CBO value of the CBS/buffer. The Pt-TiO2/In0.6Cd0.4S/Cu3BiS3 photocathode exhibits an appreciable photocurrent density of approximate to 12.20 mA cm(-2) at 0 V-RHE with onset potential of more than 0.9 V-RHE, and the ABPE of the Cu3BiS3-based photocathode reaches the highest value of 3.13%. By application of the In0.6Cd0.4S buffer, the Cu3BiS3-BiVO4 tandem cell presents a stable and excellent unbiased STH of 2.57% for over 100 h.
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Shogo Ishizuka, Riku Okamoto, Shigeru Ikeda
Advanced Materials Interfaces 9 ( 25 ) 2201266 - 2201266 2022.9
Authorship：Last author Publisher：Wiley
Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/admi.202201266
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Self-flux method in sputtered BiVO4 films for enhanced photoelectrochemical performance Reviewed
J. Liu, N. Uezono, K. Tajima, S. Pawar, M. M. Islam, S. Ikeda, T. Sakurai
ACS Appl. Energy Mater. 5 4191 - 4201 2022.4
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Effects of incorporation of Ag into a kesterite Cu2ZnSnS4 thin film on its photoelectrochemical properties for water reduction Reviewed International coauthorship
Shigeru Ikeda, Thi Hiep Nguyen, Riku Okamoto, Mikas Remeika, Imane Abdellaoui, Muhammad M. Islam, Takashi Harada, Ryu Abe, Takeaki Sakurai
Physical Chemistry Chemical Physics 24 ( 1 ) 468 - 476 2021.11
Authorship：Lead author, Corresponding author Publisher：Royal Society of Chemistry (RSC)
Incorporation of Ag into a crystalline lattice of kesterite Cu<sub>2</sub>ZnSnS<sub>4</sub> thin film was found to be effective for improvements of its photoelectrochemical properties for water reduction.
DOI： 10.1039/D1CP04075H
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Shigeru Ikeda, Riku Okamoto, Shogo Ishizuka
Applied Physics Letters 119 ( 8 ) 083902 - 083902 2021.8
Authorship：Lead author, Corresponding author Publisher：AIP Publishing
DOI： 10.1063/5.0060494
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Jiaqi Liu, Kazuya Tajima, Imane Abdellaoui, Muhammad Monirul Islam, Shigeru Ikeda, Takeaki Sakurai
Energies 14 ( 8 ) 2122-1 - 2122-10 2021.4
Joint Work
Publisher：MDPI AG
BiVO4 films were fabricated by radio frequency (RF) sputtering from a single target. The deposited BiVO4 films were found to be rich in Bi, and the reason for the Bi-richness was investigated. It was inferred from the Monte Carlo simulation that, during sputtering, the transfer process of target atoms through argon gas played a major role in this phenomenon. The transfer process resulted in an imbalanced ratio of Bi and V, arising from the difference in atom mass and interaction radius. The high RF power was found to be effective in adjusting the Bi/V ratio, influencing the sputtering yield. This type of preferential sputtering was maintained by the diffusion of target atoms from the bulk to the surface. BiVO4 films with monoclinic scheelite crystal structures were obtained at high RF power values and found to exhibit photocatalytic performances beneficial for photoanodic applications.
DOI： 10.3390/en14082122
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Mechanism of Incorporation of Zirconium into BiVO4 Visible-Light Photocatalyst Reviewed
Imane Abdellaoui, Muhammad M. Islam, Mikas Remeika, Sorai Kanno, Riku Okamoto, Kazuya Tajima, Sachin A. Pawar, Yun Hau Ng, Christian Budich, Tsuyoshi Maeda, Takahiro Wada, Shigeru Ikeda, Takeaki Sakurai
The Journal of Physical Chemistry C 125 ( 6 ) 3320 - 3326 2021.2
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3.17% efficient Cu2ZnSnS4–BiVO4 integrated tandem cell for standalone overall solar water splitting Reviewed
Dingwang Huang, Kang Wang, Lintao Li, Kuang Feng, Na An, Shigeru Ikeda, Yongbo Kuang, Yunhau Ng, Feng Jiang
Energy & Environmental Science 14 ( 3 ) 1480 - 1489 2021.1
Joint Work
Publisher：Royal Society of Chemistry (RSC)
<p>3.17% efficient Cu<sub>2</sub>ZnSnS<sub>4</sub>–BiVO<sub>4</sub> integrated tandem cell and a large scale 5 × 5 cm integrated CZTS–BiVO<sub>4</sub> tandem device for standalone overall solar water splitting was assembled for the first time.</p>
DOI： 10.1039/D0EE03892J
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Preparation of a CuGaSe2 single crystal and its photocathodic properties Invited Reviewed
S. Ikeda, W. Fujita, R. Okamoto, Y. Nose, R. Katsube, K. Yoshino, T. Harada
RSC Advances 10 ( 66 ) 40310 - 40315 2020.11
Joint Work
Authorship：Lead author, Corresponding author Publisher：ROYAL SOC CHEMISTRY
Chalcopyrite CuGaSe2 single crystals were successfully synthesized by the flux method using a home-made Bridgman-type furnace. The grown crystals were nearly stoichiometric with a Se-poor composition. Although a wafer form of the thus-obtained single crystal showed poor p-type electrical properties due to such unfavorable off-stoichiometry, these properties were found to be improved by applying a post-annealing treatment under Se vapor conditions. As a result, an electrode derived from the Se-treated single crystalline wafer showed appreciable p-type photocurrents. After deposition of a CdS ultrathin layer and a nanoparticulate Pt catalyst on the surface of the electrode, appreciable photoelectrochemical H-2 evolution was observed over the modified electrode under photoirradiation by simulated sunlight with application of a bias potential of 0 V-RHE.
DOI： 10.1039/d0ra07904a