Papers - IKEDA Shigeru
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Three‐Dimensional GeSe Microstructured Air Brick Photocathode for Advanced Solar Water Splitting Reviewed
Kang Wang, Dingwang Huang, Lintao Li, Kuang Feng, Takashi Harada, Shigeru Ikeda, Jingbo Li, Feng Jiang
Solar RRL 4 ( 5 ) 1900559-1 - 1900559-8 2020.1
Joint Work
Publisher：Wiley
Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/solr.201900559
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Photoelectrochemical CO2 Reduction to Formate with the Sacrificial Reagent Free System of Semiconductor Photocatalysts and Formate Dehydrogenase Reviewed
Ishibashi Tomoya, Higashi Masanobu, Ikeda Shigeru, Amao Yutaka
CHEMCATCHEM 11 6227 - 6235 2019.11
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Shigeru Ikeda, Shotaro Fujikawa, Takashi Harada, Thi Hiep Nguyen, Shuji Nakanishi, Tomoaki Takayama, Akihide Iwase, Akihiko Kudo
ACS Applied Energy Materials 2 ( 9 ) 6911 - 6918 2019.9
Joint Work
Publisher：American Chemical Society ({ACS})
Other Link： http://orcid.org/0000-0001-7757-4182
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Promising GeSe nanosheet based thin film photocathode for efficient and stable overall solar water splitting Reviewed
K. Wang, D. Huang, L. Yu, K. Feng, L. Li, T. Harada, S. Ikeda, F. Jiang
ACS Catalysis 9 ( 4 ) 3090 - 3097 2019.3
Joint Work
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Environmentally friendly Cu<sub>2</sub>ZnSnS<sub>4</sub>-based photocathode modified with a ZnS protection layer for efficient solar water splitting. Reviewed
Wang K, Huang D, Yu L, Gu H, Ikeda S, Jiang F
Journal of colloid and interface science 536 9 - 16 2019.2
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Growth of CuSbS2 Single Crystal as an Environmentally Friendly Thermoelectric Material Reviewed
Nagaoka Akira, Takeuchi Manato, Yoshino Kenji, Ikeda Shigeru, Yasui Shintaro, Taniyama Tomoyasu, Nishioka Kensuke
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE 216 ( 15 ) 1800861 2019.1
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Tomoya Ishibashi, Shusaku Ikeyama, Manami Ito, Shigeru Ikeda, Yutaka Amao
Chemistry Letters 42 ( 12 ) 1505 - 1508 2018.12
Joint Work
© 2018 The Chemical Society of Japan. Effective light-driven conversion of CO2 to formic acid with a hybrid system consisting of photocatalyst TiO2 nanoparticle (P25), methylviologen (MV2+) as an electron mediating molecule and biocatalyst formate dehydrogenase (FDH) in the presence of triethanolamine (TEOA) as an electron donating molecule was investigated. After 120 min irradiation with a Xe lamp (>300 nm), 152 ¯M of formic acid was produced in a CO2 saturated buffer solution containing TEOA (300 mM), TiO2 nanoparticles (6.8 mg¢L11), MV2+ (0.5 mM) and FDH (7.5 ¯M).
DOI： 10.1246/cl.180731
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Photoelectrochemical Reduction of CO2 to CO Using a CuGaS2 Thin-film Photocathode Prepared by a Spray Pyrolysis Method Reviewed
Ikeda Shigeru, Tanaka Yuta, Kawaguchi Takato, Fujikawa Shotaro, Harada Takashi, Takayama Tomoaki, Iwase Akihide, Kudo Akihiko
CHEMISTRY LETTERS 47 ( 11 ) 1424 - 1427 2018.11
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Over 1% Efficient Unbiased Stable Solar Water Splitting Based on a Sprayed Cu2ZnSnS4 Photocathode Protected by a HfO2 Photocorrosion-Resistant Film Reviewed
Huang Dingwang, Wang Kang, Yu Le, Nguyen Thi Hiep, Ikeda Shigeru, Jiang Feng
ACS ENERGY LETTERS 3 ( 8 ) 1875 - 1881 2018.7
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Structural and electric properties of CuSbS2 compound semiconductor bulk crystals Reviewed
Ikeda Shigeru, Kawaguchi Takato, Koda Yuriko, Iiyama Naoki, Harada Takashi, Nakanishi Shuji, Nakatsuka Shigeru, Nose Yoshitaro
JAPANESE JOURNAL OF APPLIED PHYSICS 57 ( 08RC09 ) 08RC09 2018.7
Joint Work
Authorship：Lead author Publisher：Japan Society of Applied Physics
Other Link： https://iopscience.iop.org/article/10.7567/JJAP.57.08RC09/meta
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Effects of Zirconium Doping Into a Monoclinic Scheelite BiVO4 Crystal on Its Structural, Photocatalytic, and Photoelectrochemical Properties Reviewed
Ikeda Shigeru, Kawaguchi Takato, Higuchi Yui, Kawasaki Naoto, Harada Takashi, Remeika Mikas, Islam Muhammad M, Sakurai Takeaki
FRONTIERS IN CHEMISTRY 6 266 2018.7
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Co-Electrodeposited Cu2ZnSnS4 Thin Film Solar Cell and Cu2ZnSnS4 Solar Cell - BiVO4 Tandem Device for Unbiased Solar Water Splitting Reviewed
Jiang Feng, Li Shuti, Ozaki Chigusa, Harada Takashi, Ikeda Shigeru
SOLAR RRL 2 ( 3 ) 1700205 2018.3
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Thi Hiep Nguyen, Takato Kawaguchi, Jakapan Chantana, Takashi Minemoto, Takashi Harada, Shuji Nakanishi, Shigeru Ikeda
ACS Applied Materials and Interfaces 10 ( 6 ) 5455 - 5463 2018.2
Joint Work
Authorship：Lead author Publisher：American Chemical Society
A silver (Ag)-incorporated kesterite Cu2ZnSnS4 (CZTS) thin film was fabricated by a facile spray pyrolysis method. Crystallographic analyses indicated successful incorporation of various amounts of Ag up to a Ag/(Ag + Cu) ratio of ca. 0.1 into the crystal lattice of CZTS in a homogeneous manner without formation of other impurity compounds. From the results of morphological investigations, Ag-incorporated films had larger crystal grains than the CZTS film. The sample with a relatively low Ag content (Ag/(Ag + Cu) of ca. 0.02) had a compact morphology without appreciable voids and pinholes. However, an increase in the Ag content in the CZTS film (Ag/(Ag + Cu) ca. 0.10) induced the formation of a large number of pinholes. As can be expected from these morphological properties, the best sunlight conversion efficiency was obtained by the solar cell based on the film with Ag/(Ag + Cu) of ca. 0.02. Electrostructural analyses of the devices suggested that the Ag-incorporated film in the device achieved reduction in the amounts of unfavorable copper on zinc antisite defects compared to the bare CZTS film. Moreover, the use of a Ag-incorporated film improved band alignment at the CdS(buffer)-CZTS interface. These alterations should also contribute to enhancement of device properties.
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Hasyiya Karimah Adli, Takashi Harada, Shuji Nakanishi, Shigeru Ikeda
PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19 ( 39 ) 26898 - 26905 2017.10
Joint Work
Publisher：ROYAL SOC CHEMISTRY
The effects of surface treatment with TiCl4 on the structural and electrochemical properties of a porous titanium oxide (pTiO(2)) layer deposited on a fluorine-doped tin oxide (FTO)/glass substrate covered with a dense TiO2 layer (pTiO(2)/dTiO(2)/FTO/glass) were systematically investigated in order to obtain an optimum pTiO(2) layer for use in CH3NH3PbI3 perovskite solar cells. As confirmed by thermal desorption spectroscopy (TDS) analyses, the amount of surface hydroxyl groups in pTiO(2) varied when the pTiO(2)/dTiO(2)/FTO/glass sample was treated with solutions with different concentrations of TiCl4 (i.e., 20, 50, 80, and 100 mM). Photoelectrochemical (PEC) analyses of the pTiO(2)/dTiO(2)/FTO/glass samples after TiCl4 treatment showed significant increments of photocurrent densities compared to the pTiO(2)/dTiO(2)/FTO/glass sample without TiCl4 treatment regardless of the concentration of TiCl4 used in the solution. Electrochemical impedance spectroscopy (EIS) analyses of the TiCl4-treated pTiO(2)/dTiO(2)/FTO/glass samples also indicated a lower recombination probability with an increase in TiCl4 concentration. The results suggest that TiCl4 treatment resulted in passivation of defect sites on the surface of the TiO2 nanoparticles as well as improvement of the interconnectivity between the TiO2 nanoparticles in pTiO(2). In contrast, the power conversion efficiencies (PCEs) and short circuit current densities of CH3NH3PbI3 perovskite solar cells based on these pTiO(2)/dTiO(2)/FTO/glass samples exhibited volcano-like patterns depending on the TiCl4 concentration used for the pTiO(2) treatment: the highest PCE was obtained by using pTiO(2)/d TiO2/FTO/glass treated with 50 mM of TiCl4 solution. Structural analysis of the CH3NH3PbI3 perovskite part performed by X-ray diffraction (XRD) indicated that the formation of CH3NH3PbI3 perovskite was inhibited by the presence of surface hydroxyl groups in the pTiO(2) film without TiCl4 treatment. TiCl4 treatment using TiCl4 solutions with concentrations up to 50 mM enhanced the formation of the CH3NH3PbI3 perovskite layer, whereas TiCl4 treatment using TiCl4 solutions with concentrations higher than 50 mM was detrimental due to the formation of nanoparticulate TiO2 aggregates that induce poor porosity and act as recombination sites.
DOI： 10.1039/c7cp04132b
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Photoelectrochemical water reduction over wide gap (Ag,Cu)(In,Ga)S-2 thin film photocathodes Reviewed
Wilman Septina, Minori Sugimoto, Ding Chao, Qing Shen, Shigeru Nakatsuka, Yoshitaro Nose, Takashi Harada, Shigeru Ikeda
PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19 ( 19 ) 12502 - 12508 2017.5
Joint Work
Authorship：Lead author Publisher：ROYAL SOC CHEMISTRY
The effects of partial replacement of Cu with Ag in a Cu(In,Ga) S-2 (CIGS) thin film on its structural, optical, electrostructural, and photoelectrochemical (PEC) properties were investigated, in order to improve its performance for PEC water reduction under sunlight illumination. Results from X-ray diffraction (XRD) analyses revealed the successful partial replacement of Cu with Ag to form solid-solutions with different Ag/(Ag + Cu) ratios (A(x)CIGS, x = Ag/(Ag + Cu) = 0.1, 0.2, 0.3 and 0.4), as confirmed by a gradual change in the (112) reflections to smaller 2 theta angles with increasing Ag/(Ag + Cu) ratio. Analyses of the photoabsorption properties of the materials using photoacoustic spectroscopy indicated changes in the band gap energies associated with increasing the Ag/(Ag + Cu) ratio. In addition, valence band maximum potentials of A(x) CIGS were deepened gradually with increasing Ag/(Ag + Cu) ratio. After modifying these A(x) CIGS films with a CdS ultrathin (ca. 70 nm) layer and a Pt catalyst, the PEC water reduction properties were evaluated in an electrolyte solution with the pH adjusted to 6.5, under simulated sunlight (AM 1.5G) radiation. Compared to the CdS- and Pt-modified Ag-free A(x) CIGS (A(0) CIGS) films, appreciable enhancements in the PEC properties were observed for electrodes based on A(x) CIGS (x 4 0) films, and the best PEC performance was obtained for the electrode based on the A(0.2) CIGS film. However, the electrode derived from the A(x) CIGS film with Ag/(Ag + Cu) ratios higher than 0.3 showed diminished PEC properties due to the partial conversion of its semiconducting properties from p-type to n-type.
DOI： 10.1039/c7cp01348e
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Investigation on Stability of Electroplated-Sulfurized CuInS2-based Photocathode Modified with an In2S3 Layer for H-2 Evolution under Various pH Conditions Reviewed
Gunawan, Haris Abdul, Widiyandari Hendri, Septina Wilman, Ikeda Shigeru
ORIENTAL JOURNAL OF CHEMISTRY 33 ( 2 ) 556 - 561 2017.4
Joint Work
Publisher：Oriental Scientific Publishing Company
We investigated photoelectrochemical water splitting properties of Pt-In2S3/CuInS2 photocathodes from near neutral toward basic condition (pH 6, 9, and 13). Half-cell solar-to-hydrogen (HC-STH) of Pt-In2S3/CuInS2 measured under 0.2 M NaH2PO4 was the highest when the pH of the solution was 13 (4.7% at 0.42 V vs. RHE) with a maximum photocurrent density of 16.3 mA cm-2 (at 0 V vs. RHE) and onset potential of 0.9 V vs. RHE (defined as cathodic photocurrent of 0.1 mA cm-2). However, it suffers from rapid degradation of the photocurrent over the time course when kept at 0 V vs. RHE under constant illumination. On the other hand, the photocathode showed relatively stable photocurrent when measured under near neutral condition (pH 6): HC-STH of 2.85% (at 0.28 V vs. RHE) with a maximum photocurrent density of 16.3 mA cm-2 (at 0 V vs. RHE) and onset potential of 0.72 V vs. RHE were obtained from the photocathode. Passivation using In2S3 oxygen-free can stabilize the photocathode at alkaline pH (pH 13).
DOI： 10.13005/ojc/330202
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Effects of Indium Incorporation on Structural and Photovoltaic Properties of Cu2ZnSnS4 Thin Films Reviewed
Thi Hiep Nguyen; Harada, Takashi; Fujikawa, Shotaro; Nakanishi, Shuji; Ikeda, Shigeru
ECS TRANSACTIONS 75 ( 50 ) 15 - 22 2017.1
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Cu2ZnSnS4-based Thin Film Solar Cells with More Than 8% Conversion Efficiency Obtained by Using A Spray Pyrolysis Technique
Thi Hiep Nguyen; Harada, Takashi; Nakanishi, Shuji; Ikeda, Shigeru
PVSC, 2016 IEEE 43rd ( 7749637 ) 470 - 472 2016.11
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Impact of Precursor Compositions on the Structural and Photovoltaic Properties of Spray-Deposited Cu2ZnSnS4 Thin Films Reviewed
Thi Hiep Nguyen, Shotaro Fujikawa, Takashi Harada, Jakapan Chantana, Takashi Minemoto, Shuji Nakanishi, Shigeru Ikeda
CHEMSUSCHEM 9 ( 17 ) 2414 - 2420 2016.9
Joint Work
Authorship：Lead author Publisher：WILEY-V C H VERLAG GMBH
Pure sulfide Cu2ZnSnS4 thin films were fabricated on Mo-coated glass substrates by facile spray deposition of aqueous precursor solutions containing Cu(NO3)(2), Zn(NO3)(2), Sn(CH3SO3)(2), and thiourea followed by annealing at 600 degrees C. When a precursor solution containing a stoichiometric composition of Cu, Zn, and Sn was used, the resulting Cu2ZnSnS4 thin film contained a Cu2-xS impurity phase owing to the evaporation of Sn components during the annealing process. The Cu2-xS impurity in the Cu2ZnSnS4 thin film was removed by reducing the concentration of Cu in the precursor solution. This resulted in an improvement of the structural features (i.e., grain sizes and compactness) as well as the electric properties such as acceptor densities, the nature of the acceptor defects, and carrier lifetimes. A solar cell based on the Cu2ZnSnS4 film with an empirically optimal composition showed conversion efficiency of 8.1%. The value achieved was one of the best efficiencies of Cu2ZnSnS4-based cells derived from a non-vacuum process.
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Effect of Indium Doping on Surface Optoelectrical Properties of Cu2ZnSnS4 Photoabsorber and Interfacial/Photovoltaic Performance of Cadmium Free In2S3/Cu2ZnSnS4 Heterojunction Thin Film Solar Cell Reviewed
Feng Jiang, Chigusa Ozaki, Gunawan, Takashi Harada, Zeguo Tang, Takashi Minemoto, Yoshitaro Nose, Shigeru Ikeda
CHEMISTRY OF MATERIALS 28 ( 10 ) 3283 - 3291 2016.5
Joint Work
Authorship：Lead author Publisher：AMER CHEMICAL SOC
Maximum conversion efficiency of 6.9% was 20 obtained over an electrodeposited Cu(2)ZnSnS(4-)based thin film solar cell with a Cd-free In2S3 buffer layer by applying a rapid post-heat treatment to the In2S3/Cu2ZnSnS4 stacked layer. It was found that post-heating of the In2S3/Cu2ZnSnS4 stack promoted an increment of the acceptor density of the Cu2ZnSnS4 layer close to the In2S3-Cu2ZnSnS4 heterointerface of the In2S3/Cu2ZnSnS4 stack. Moreover, the diffusion of In also resulted in a red-shift of the band gap energy of Cu2ZnSnS4 from 1.47 to 1.40 eV. Due to extension of external quantum efficiency response of the solar cell to the long wavelength region, the solar cell based on the post-heated In2S3/Cu2ZnSnS4 stack reached appreciably large short circuit current density of more than 20 mA cm(-2). The energy difference between the conduction band minimum of In2S3 and that of Cu2ZnSnS4 at the In2S3/Cu2ZnSnS4 heterointerface was determined to be a slightly positive value of 0.11 eV, indicating formation of a "notch-type" conduction band offset for efficient suppression of the interface recombination.