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Takeo Oku
Department of Materials Science The University of Shiga Prefecture 2500 Hassaka Hikone Shiga 522-8533 Japan

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Research article
Published: 05 August 2021 in physica status solidi (a)
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CH3NH3PbI3 (MAPbI3) perovskite solar cells with guanidinium (C(NH2)3+, GA+) are fabricated at 150 °C using 3CH3NH3I:PbCl2 starting composition in ambient atmosphere, and characterized. Their photoconversion efficiencies and stabilities are improved by the addition of a small amount of GA+. Lattice volumes are increased by the addition of GA+, which confirms the occurrence of GA+ substitution at the CH3NH3 site. Energy gaps are decreased by the addition of GA+, which agrees well with the results of molecular orbital calculation and band calculation. The carrier trap density is reduced by the GA+ addition, which suggests that lattice defects are suppressed by the GA+ doping. Two-year stabilities of the devices in ordinary air are also investigated, which indicate the effectiveness of GA addition.

ACS Style

Taku Kishimoto; Takeo Oku; Atsushi Suzuki; Naoki Ueoka. Additive Effects of Guanidinium Iodide on CH 3 NH 3 PbI 3 Perovskite Solar Cells. physica status solidi (a) 2021, 2100396 .

AMA Style

Taku Kishimoto, Takeo Oku, Atsushi Suzuki, Naoki Ueoka. Additive Effects of Guanidinium Iodide on CH 3 NH 3 PbI 3 Perovskite Solar Cells. physica status solidi (a). 2021; ():2100396.

Chicago/Turabian Style

Taku Kishimoto; Takeo Oku; Atsushi Suzuki; Naoki Ueoka. 2021. "Additive Effects of Guanidinium Iodide on CH 3 NH 3 PbI 3 Perovskite Solar Cells." physica status solidi (a) , no. : 2100396.

Journal article
Published: 31 May 2021 in Coatings
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CH3NH3PbI3 perovskite photovoltaic devices treated with a polysilane layer were fabricated and characterized. Decaphenylcyclopentasilane (DPPS) in chlorobenzene solution was deposited at the surface of the perovskite layer, and the resulting device was annealed at 140–260 °C. The photoconversion efficiencies of the DPPS-treated device remained high even after 255 days in ambient air. Raman scattering spectroscopy and ab initio molecular orbital calculations of DPPS suggested that it increased hole transport efficiency in the treated devices, which was confirmed from the high shunt resistances of the DPPS-treated devices.

ACS Style

Takeo Oku; Masaya Taguchi; Atsushi Suzuki; Kaede Kitagawa; Yugo Asakawa; Satoshi Yoshida; Masanobu Okita; Satoshi Minami; Sakiko Fukunishi; Tomoharu Tachikawa. Effects of Polysilane Addition to Chlorobenzene and High Temperature Annealing on CH3NH3PbI3 Perovskite Photovoltaic Devices. Coatings 2021, 11, 665 .

AMA Style

Takeo Oku, Masaya Taguchi, Atsushi Suzuki, Kaede Kitagawa, Yugo Asakawa, Satoshi Yoshida, Masanobu Okita, Satoshi Minami, Sakiko Fukunishi, Tomoharu Tachikawa. Effects of Polysilane Addition to Chlorobenzene and High Temperature Annealing on CH3NH3PbI3 Perovskite Photovoltaic Devices. Coatings. 2021; 11 (6):665.

Chicago/Turabian Style

Takeo Oku; Masaya Taguchi; Atsushi Suzuki; Kaede Kitagawa; Yugo Asakawa; Satoshi Yoshida; Masanobu Okita; Satoshi Minami; Sakiko Fukunishi; Tomoharu Tachikawa. 2021. "Effects of Polysilane Addition to Chlorobenzene and High Temperature Annealing on CH3NH3PbI3 Perovskite Photovoltaic Devices." Coatings 11, no. 6: 665.

Journal article
Published: 10 May 2021 in Applied Physics Express
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ACS Style

Ken-Ichi Matsuoka; Shoto Banya; Ippei Hosoi; Natsuki Koyama; Kazumasa Suzuki; Balachandran Jeyadevan; Takeo Oku; Katsuhiko Fujita; Sunao Yamada; Tsuyoshi Akiyama. Preparation of silver nanoparticle-loaded C60-ethylenediamine adduct microparticles and their application to photoelectric conversion. Applied Physics Express 2021, 1 .

AMA Style

Ken-Ichi Matsuoka, Shoto Banya, Ippei Hosoi, Natsuki Koyama, Kazumasa Suzuki, Balachandran Jeyadevan, Takeo Oku, Katsuhiko Fujita, Sunao Yamada, Tsuyoshi Akiyama. Preparation of silver nanoparticle-loaded C60-ethylenediamine adduct microparticles and their application to photoelectric conversion. Applied Physics Express. 2021; ():1.

Chicago/Turabian Style

Ken-Ichi Matsuoka; Shoto Banya; Ippei Hosoi; Natsuki Koyama; Kazumasa Suzuki; Balachandran Jeyadevan; Takeo Oku; Katsuhiko Fujita; Sunao Yamada; Tsuyoshi Akiyama. 2021. "Preparation of silver nanoparticle-loaded C60-ethylenediamine adduct microparticles and their application to photoelectric conversion." Applied Physics Express , no. : 1.

Correction
Published: 13 April 2021 in Materials Advances
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Correction for ‘Effects of mixed-valence states of Eu-doped FAPbI3 perovskite crystals studied by first-principles calculation’ by Atsushi Suzuki et al., Mater. Adv., 2021, DOI: 10.1039/D0MA00994F.

ACS Style

Atsushi Suzuki; Takeo Oku. Correction: Effects of mixed-valence states of Eu-doped FAPbI3 perovskite crystals studied by first-principles calculation. Materials Advances 2021, 1 .

AMA Style

Atsushi Suzuki, Takeo Oku. Correction: Effects of mixed-valence states of Eu-doped FAPbI3 perovskite crystals studied by first-principles calculation. Materials Advances. 2021; ():1.

Chicago/Turabian Style

Atsushi Suzuki; Takeo Oku. 2021. "Correction: Effects of mixed-valence states of Eu-doped FAPbI3 perovskite crystals studied by first-principles calculation." Materials Advances , no. : 1.

Journal article
Published: 25 March 2021 in Journal of Sol-Gel Science and Technology
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A composite powder of titanium oxide and silver nanoparticles was obtained by using a combination of the sol–gel process and ultraviolet light induced reduction of silver ion via one-pot synthesis. After calcination, silver nanoparticles were embedded in an anatase crystalline titanium oxide matrix, as revealed by transmission electron microscopy. Silver nanoparticles with sizes ranging from a few nanometers to several tens of nanometers were observed in the titanium oxide matrix. The crystalline titanium oxide-silver nanoparticle composite powder decomposed the methylene blue dye upon visible light irradiation. The decomposition rate of the dye using the crystalline titanium oxide-silver nanoparticle composite powders was considerably faster than that in the case of the reference titanium oxide powder without silver nanoparticle. Thus, plasmon-induced charge separation from the silver nanoparticle to the conduction band of titanium oxide expected to occur, and holes on silver nanoparticles or induced active oxygen decomposed methylene blue in the solution or adsorbed on titanium oxide.

ACS Style

Suguru Higashida; Shotaro Yoshida; Natsuki Koyama; Kazumasa Suzuki; Takeo Oku; Tsuyoshi Akiyama. One-pot synthesis of visible-light-responsive titanium oxide photocatalyst with embedded silver nanoparticles. Journal of Sol-Gel Science and Technology 2021, 98, 281 -287.

AMA Style

Suguru Higashida, Shotaro Yoshida, Natsuki Koyama, Kazumasa Suzuki, Takeo Oku, Tsuyoshi Akiyama. One-pot synthesis of visible-light-responsive titanium oxide photocatalyst with embedded silver nanoparticles. Journal of Sol-Gel Science and Technology. 2021; 98 (2):281-287.

Chicago/Turabian Style

Suguru Higashida; Shotaro Yoshida; Natsuki Koyama; Kazumasa Suzuki; Takeo Oku; Tsuyoshi Akiyama. 2021. "One-pot synthesis of visible-light-responsive titanium oxide photocatalyst with embedded silver nanoparticles." Journal of Sol-Gel Science and Technology 98, no. 2: 281-287.

Paper
Published: 15 March 2021 in Materials Advances
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Effects of mixed-valence states of europium (Eu)-incorporated CH(NH2)2PbI3 (FAPbI3) and CH3NH3PbI3 (MAPbI3) perovskite crystals on electronic structures were investigated by first-principles calculation.

ACS Style

Atsushi Suzuki; Takeo Oku. Effects of mixed-valence states of Eu-doped FAPbI3 perovskite crystals studied by first-principles calculation. Materials Advances 2021, 2, 2609 -2616.

AMA Style

Atsushi Suzuki, Takeo Oku. Effects of mixed-valence states of Eu-doped FAPbI3 perovskite crystals studied by first-principles calculation. Materials Advances. 2021; 2 (8):2609-2616.

Chicago/Turabian Style

Atsushi Suzuki; Takeo Oku. 2021. "Effects of mixed-valence states of Eu-doped FAPbI3 perovskite crystals studied by first-principles calculation." Materials Advances 2, no. 8: 2609-2616.

Original research article
Published: 11 February 2021 in Journal of Electronic Materials
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Ni- and Co-incorporated CH3NH3PbI3 perovskite solar cells were fabricated and characterized to optimize the photovoltaic and optical properties related to surface morphology, crystal growth and orientation, and electronic structures. Partially replacing Pb with Ni or Co in the perovskite crystals improved the photovoltaic performance and carrier mobility based on the effective mass in the band structure. In particular, the addition of both Ni and Rb compounds to perovskite improved the long-term stability of the photovoltaic cells, which depended on surface modification and coverage, crystal growth, and the high (100) orientation in the perovskite layer. The short-circuit current density of the cells was increased by promoting the generation and mobility of photoinduced carriers, which were inversely proportional to the effective mass ratio. Electron correlation was associated with the promotion of charge transfer owing to the hybridization between the 3d orbitals of Ni and the 5p orbitals of the I atoms near the valence band state.

ACS Style

Atsushi Suzuki; Mari Oe; Takeo Oku. Fabrication and Characterization of Ni-, Co-, and Rb-Incorporated CH3NH3PbI3 Perovskite Solar Cells. Journal of Electronic Materials 2021, 50, 1980 -1995.

AMA Style

Atsushi Suzuki, Mari Oe, Takeo Oku. Fabrication and Characterization of Ni-, Co-, and Rb-Incorporated CH3NH3PbI3 Perovskite Solar Cells. Journal of Electronic Materials. 2021; 50 (4):1980-1995.

Chicago/Turabian Style

Atsushi Suzuki; Mari Oe; Takeo Oku. 2021. "Fabrication and Characterization of Ni-, Co-, and Rb-Incorporated CH3NH3PbI3 Perovskite Solar Cells." Journal of Electronic Materials 50, no. 4: 1980-1995.

Journal article
Published: 13 January 2021 in Japanese Journal of Applied Physics
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Classification of citrate-stabilized silver nanoparticles was performed by a combination of centrifugation and redispersion. Repeated the classification processes led to a convergence of similarly sized nanoparticles, which in turn decreased their size deviations. This tendency corresponds to the change in the zeta potentials of the silver nanoparticles. Densely-packed sphere-shaped silver nanoparticle thin-film assemblies were fabricated by a liquid/liquid interfacial precipitation process using appropriately classified silver nanoparticles. Surface enhanced-Raman scattering efficiencies of these thin-film assemblies of silver nanoparticles were varied and could be optimized by the number of classification processes.

ACS Style

Natsuki Koyama; Tsuyoshi Akiyama; Takeo Oku. Fabrication and surface-enhanced Raman scattering properties of thin-film assemblies of classified silver nanoparticles. Japanese Journal of Applied Physics 2021, 60, 027002 .

AMA Style

Natsuki Koyama, Tsuyoshi Akiyama, Takeo Oku. Fabrication and surface-enhanced Raman scattering properties of thin-film assemblies of classified silver nanoparticles. Japanese Journal of Applied Physics. 2021; 60 (2):027002.

Chicago/Turabian Style

Natsuki Koyama; Tsuyoshi Akiyama; Takeo Oku. 2021. "Fabrication and surface-enhanced Raman scattering properties of thin-film assemblies of classified silver nanoparticles." Japanese Journal of Applied Physics 60, no. 2: 027002.

Journal article
Published: 01 December 2020 in AIP Advances
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The effects of doping with alkali metals and formamidinium cations on CH3NH3(Rb)Pb(Cu)I3(Cl,Br) perovskite photovoltaic cells were investigated. Lattice constants were slightly decreased and increased by K and Na doping, respectively. This indicated that Na atoms occupied interstitial sites in the perovskite crystal. The conversion efficiencies for most of the devices decreased after one year. However, the conversion efficiency for the CH3NH3(Na,Rb)Pb(Cu)I3(Cl,Br) photovoltaic cell was unchanged after one year. The Na-doped perovskite provided the smallest carrier trap density, which suggested that lattice defects were suppressed by Na doping. First principles calculations supported these experimental results.

ACS Style

Naoki Ueoka; Takeo Oku; Atsushi Suzuki. Effects of doping with Na, K, Rb, and formamidinium cations on (CH3NH3)0.99Rb0.01Pb0.99Cu0.01I3−x(Cl, Br)x perovskite photovoltaic cells. AIP Advances 2020, 10, 125023 .

AMA Style

Naoki Ueoka, Takeo Oku, Atsushi Suzuki. Effects of doping with Na, K, Rb, and formamidinium cations on (CH3NH3)0.99Rb0.01Pb0.99Cu0.01I3−x(Cl, Br)x perovskite photovoltaic cells. AIP Advances. 2020; 10 (12):125023.

Chicago/Turabian Style

Naoki Ueoka; Takeo Oku; Atsushi Suzuki. 2020. "Effects of doping with Na, K, Rb, and formamidinium cations on (CH3NH3)0.99Rb0.01Pb0.99Cu0.01I3−x(Cl, Br)x perovskite photovoltaic cells." AIP Advances 10, no. 12: 125023.

Proceedings
Published: 11 November 2020 in Materials Proceedings
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Effects of co-addition of CuBr2 and NaCl to CH3NH3PbI3(Cl) perovskite solar cells were investigated on the photovoltaic properties and microstructures. Short-circuit current densities and conversion efficiencies were improved by the simultaneous addition of CuBr2 and NaCl. In addition, the efficiencies of the devices were maintained after 10 weeks. The perovskite structure changed from a tetragonal to a cubic system by the addition of Na, which resulted in the improvement of the perovskite crystal’s stabilization.

ACS Style

Naoki Ueoka; Takeo Oku. Effects of Co-Addition of CuBr2 and NaCl to CH3NH3PbI3(Cl) Perovskite Solar Cells. Materials Proceedings 2020, 4, 54 .

AMA Style

Naoki Ueoka, Takeo Oku. Effects of Co-Addition of CuBr2 and NaCl to CH3NH3PbI3(Cl) Perovskite Solar Cells. Materials Proceedings. 2020; 4 (1):54.

Chicago/Turabian Style

Naoki Ueoka; Takeo Oku. 2020. "Effects of Co-Addition of CuBr2 and NaCl to CH3NH3PbI3(Cl) Perovskite Solar Cells." Materials Proceedings 4, no. 1: 54.

Proceedings
Published: 11 November 2020 in Materials Proceedings
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Perovskite solar cells, in which decaphenylcyclopentasilane (DPPS) layers were formed on the surface of a CH3NH3PbI3-based perovskite layer, were developed. The photovoltaic properties were improved by controlling the annealing temperature of the perovskite layer. For perovskite layers annealed at high temperatures in the range of 180–220 °C, the perovskite crystals were densely formed and the surface coverage of the perovskite layer was improved. The DPPS-laminated devices suppressed the formation of PbI2 crystals, and the stability was improved by the DPPS layer. Furthermore, the conversion efficiencies were improved over extended periods of time.

ACS Style

Takeo Oku; Masaya Taguchi; Satsuki Kandori; Atsushi Suzuki; Masanobu Okita; Satoshi Minami; Sakiko Fukunishi; Tomoharu Tachikawa. Development of Polysilane-Inserted Perovskite Solar Cells. Materials Proceedings 2020, 4, 51 .

AMA Style

Takeo Oku, Masaya Taguchi, Satsuki Kandori, Atsushi Suzuki, Masanobu Okita, Satoshi Minami, Sakiko Fukunishi, Tomoharu Tachikawa. Development of Polysilane-Inserted Perovskite Solar Cells. Materials Proceedings. 2020; 4 (1):51.

Chicago/Turabian Style

Takeo Oku; Masaya Taguchi; Satsuki Kandori; Atsushi Suzuki; Masanobu Okita; Satoshi Minami; Sakiko Fukunishi; Tomoharu Tachikawa. 2020. "Development of Polysilane-Inserted Perovskite Solar Cells." Materials Proceedings 4, no. 1: 51.

Proceedings
Published: 11 November 2020 in Materials Proceedings
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Additive effects of guanidinium [C(NH2)3, GA] iodide, formamidinium [CH(NH2)2, FA] iodide, and guanidinium chloride to CH3NH3PbI3-based photovoltaic devices were investigated. Short-circuit current densities, open-circuit voltages, series resistances and shunt resistances were improved by the GA addition. The short-circuit current densities were increased by FA addition with GA, and the external quantum efficiencies increased, which resulted in suppression of pinholes in perovskite layers by the GA addition. X-ray diffraction showed that the lattice constants of the perovskite crystals increased by the GA and FA addition, and that the GA substituted partially at the CH3NH3-site.

ACS Style

Taku Kishimoto; Atsushi Suzuki; Naoki Ueoka; Takeo Oku. Effects of Guanidinium and Formamidinium Addition to CH3NH3PbI3-Based Perovskite Solar Cells. Materials Proceedings 2020, 4, 55 .

AMA Style

Taku Kishimoto, Atsushi Suzuki, Naoki Ueoka, Takeo Oku. Effects of Guanidinium and Formamidinium Addition to CH3NH3PbI3-Based Perovskite Solar Cells. Materials Proceedings. 2020; 4 (1):55.

Chicago/Turabian Style

Taku Kishimoto; Atsushi Suzuki; Naoki Ueoka; Takeo Oku. 2020. "Effects of Guanidinium and Formamidinium Addition to CH3NH3PbI3-Based Perovskite Solar Cells." Materials Proceedings 4, no. 1: 55.

Proceedings
Published: 11 November 2020 in Materials Proceedings
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The influence of alkali metals (Na, K) or transition metals (Co, Cr, Cu, and Y) incorporated into perovskite crystal on the electronic structures, spectroscopic, and magnetic properties, and thermodynamic properties was investigated by first-principles calculation. Incorporation of Na or K into the perovskite crystal generated 3s, 3p, 4s, and 4p orbitals of Na or K above the conduction band, which promoted the charge transfer from alkali metal to the conduction band, accelerating the electron diffusion related to the photovoltaic properties. For the Cr, Cu, and Y-incorporated perovskite crystals, the electron density distribution of d-p hybrid orbital on the transition metal and iodine halogen ligand were delocalized at frontier orbital. The electronic correlation worked in between the localized spin on 3d orbital of the metal, and the itinerant carriers on the 5p orbital of the iodine halogen ligand and the 6p orbital of the lead atom in the perovskite crystal. The vibration behavior of the Raman and infrared spectra were associated with change of polarization and slight distortion near the coordination structure. The considerable splitting of chemical shift of 127I-NMR and 207Pb-NMR in the magnetic field was caused by crystal field splitting with the Jahn-Teller effect with nearest-neighbor nuclear quadrupole interaction based on the charge distribution. Decrease of the Gibbs free energy and entropy indicated the thermodynamic stabilization without scattering carrier diffusion as phonon effectiveness. The decrease of the entropy was based on a slight change of stretching vibration mode of Pb–I bond with vending mode of N–H and C–H bonds in the infrared and Raman spectra. The minor addition of alkali metal or transition metal into the perovskite crystal would improve the photovoltaic properties, open voltage related to band gap, and short-circuit current density based on the carrier diffusion with phonon effectiveness.

ACS Style

Atsushi Suzuki; Takeo Oku. Electronic Structures, Spectroscopic Properties, and Thermodynamic Characterization of Alkali Metal and Transition Metal Incorporated Perovskite Crystals by First-Principles Calculation. Materials Proceedings 2020, 4, 79 .

AMA Style

Atsushi Suzuki, Takeo Oku. Electronic Structures, Spectroscopic Properties, and Thermodynamic Characterization of Alkali Metal and Transition Metal Incorporated Perovskite Crystals by First-Principles Calculation. Materials Proceedings. 2020; 4 (1):79.

Chicago/Turabian Style

Atsushi Suzuki; Takeo Oku. 2020. "Electronic Structures, Spectroscopic Properties, and Thermodynamic Characterization of Alkali Metal and Transition Metal Incorporated Perovskite Crystals by First-Principles Calculation." Materials Proceedings 4, no. 1: 79.

Journal article
Published: 13 September 2020 in Energies
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Polysilane-inserted CH3NH3PbI3 perovskite photovoltaic devices combined with potassium and formamidinium iodides were fabricated and characterized. Decaphenylcyclopentasilane layers were inserted at the perovskite/hole transport interface and annealed across a temperature range of 180–220 °C. These polysilane-coated cells prevented PbI2 formation, and the conversion efficiencies were improved over extended periods of time.

ACS Style

Takeo Oku; Satsuki Kandori; Masaya Taguchi; Atsushi Suzuki; Masanobu Okita; Satoshi Minami; Sakiko Fukunishi; Tomoharu Tachikawa. Polysilane-Inserted Methylammonium Lead Iodide Perovskite Solar Cells Doped with Formamidinium and Potassium. Energies 2020, 13, 4776 .

AMA Style

Takeo Oku, Satsuki Kandori, Masaya Taguchi, Atsushi Suzuki, Masanobu Okita, Satoshi Minami, Sakiko Fukunishi, Tomoharu Tachikawa. Polysilane-Inserted Methylammonium Lead Iodide Perovskite Solar Cells Doped with Formamidinium and Potassium. Energies. 2020; 13 (18):4776.

Chicago/Turabian Style

Takeo Oku; Satsuki Kandori; Masaya Taguchi; Atsushi Suzuki; Masanobu Okita; Satoshi Minami; Sakiko Fukunishi; Tomoharu Tachikawa. 2020. "Polysilane-Inserted Methylammonium Lead Iodide Perovskite Solar Cells Doped with Formamidinium and Potassium." Energies 13, no. 18: 4776.

Research article
Published: 30 July 2020 in ACS Applied Energy Materials
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The effects of the co-addition of NaCl and CuBr2 to CH3NH3PbI3–xClx-based photovoltaic devices are investigated. The lattice constant of CH3NH3Pb(Cu)I3–xClx(Br) is slightly increased by the addition of NaCl, and the X-ray diffraction peaks corresponding to the tetragonal symmetry disappears after several weeks, which indicates a structural transition from the tetragonal to the cubic system by the co-addition of NaCl and CuBr2. A microstructural model, where Na occupies the CH3NH3 vacancy site, is proposed. The Jahn–Teller effect of the Cu d electrons leads to the formation of a cubic system at elevated temperatures, and the conversion efficiency is maintained for 10 weeks for the device with a co-addition of CuBr2 and NaCl.

ACS Style

Naoki Ueoka; Takeo Oku. Effects of Co-Addition of Sodium Chloride and Copper(II) Bromide to Mixed-Cation Mixed-Halide Perovskite Photovoltaic Devices. ACS Applied Energy Materials 2020, 3, 7272 -7283.

AMA Style

Naoki Ueoka, Takeo Oku. Effects of Co-Addition of Sodium Chloride and Copper(II) Bromide to Mixed-Cation Mixed-Halide Perovskite Photovoltaic Devices. ACS Applied Energy Materials. 2020; 3 (8):7272-7283.

Chicago/Turabian Style

Naoki Ueoka; Takeo Oku. 2020. "Effects of Co-Addition of Sodium Chloride and Copper(II) Bromide to Mixed-Cation Mixed-Halide Perovskite Photovoltaic Devices." ACS Applied Energy Materials 3, no. 8: 7272-7283.

Journal article
Published: 20 April 2020 in Coatings
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Photovoltaic characteristics of solar cell devices in which ethylammonium (EA) and formamidinium (FA) were added to CH3NH3PbI3 perovskite photoactive layers were investigated. The thin films for the devices were deposited by an ordinary spin-coating technique in ambient air, and the X-ray diffraction analysis revealed changes of the lattice constants, crystallite sizes and crystal orientations. By adding FA and EA, surface defects of the perovskite layer decreased, and the photoelectric parameters were improved. In addition, the highly (100) crystal orientations and device stabilities were improved by the EA and FA addition.

ACS Style

Kousuke Nishi; Takeo Oku; Taku Kishimoto; Naoki Ueoka; Atsushi Suzuki. Photovoltaic Characteristics of CH3NH3PbI3 Perovskite Solar Cells Added with Ethylammonium Bromide and Formamidinium Iodide. Coatings 2020, 10, 410 .

AMA Style

Kousuke Nishi, Takeo Oku, Taku Kishimoto, Naoki Ueoka, Atsushi Suzuki. Photovoltaic Characteristics of CH3NH3PbI3 Perovskite Solar Cells Added with Ethylammonium Bromide and Formamidinium Iodide. Coatings. 2020; 10 (4):410.

Chicago/Turabian Style

Kousuke Nishi; Takeo Oku; Taku Kishimoto; Naoki Ueoka; Atsushi Suzuki. 2020. "Photovoltaic Characteristics of CH3NH3PbI3 Perovskite Solar Cells Added with Ethylammonium Bromide and Formamidinium Iodide." Coatings 10, no. 4: 410.

Advanced nano materials
Published: 04 March 2020 in Journal of Materials Science
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Influence of alkali metals such as sodium (Na) and potassium (K) in methyl ammonium lead iodide CH3NH3PbI3 perovskite crystal on electronic structures, spectroscopic properties, and thermodynamic properties was investigated by first-principles calculation. Partial substitution of CH3NH3 with Na or K in the perovskite crystal generated 3s, 3p, 4s, and 4p orbitals of Na or K above conduction band, which promoted the charge transfer from the alkali metals to the conduction band, accelerating the carrier generation and diffusion related to the photovoltaic performances. The molar absorption coefficient and oscillation strength were increased by a slight deviation of the charge distribution near ligand in the coordination structure. The splitting of chemical shift of 127I-NMR in magnetic field was caused by a slight perturbation of the coordination structure with nuclear quadrupole interaction based on electronic field gradient. Decrease of the Gibbs free energy and entropy indicated the thermodynamic stabilization without scattering carrier diffusion as phonon effectiveness. The decrease of the entropy was based on a slight change of stretching vibration mode of Pb–I bond with vending mode of N–H and C–H bonds in the infrared and Raman spectra. The minor addition of 12.5% Na or K into the perovskite crystal will improve the photovoltaic properties, open voltage related to band gap, and short-circuit current density based on the carrier diffusion with phonon effectiveness.

ACS Style

Atsushi Suzuki; Yasutaka Miyamoto; Takeo Oku. Electronic structures, spectroscopic properties, and thermodynamic characterization of sodium- or potassium-incorporated CH3NH3PbI3 by first-principles calculation. Journal of Materials Science 2020, 55, 9728 -9738.

AMA Style

Atsushi Suzuki, Yasutaka Miyamoto, Takeo Oku. Electronic structures, spectroscopic properties, and thermodynamic characterization of sodium- or potassium-incorporated CH3NH3PbI3 by first-principles calculation. Journal of Materials Science. 2020; 55 (23):9728-9738.

Chicago/Turabian Style

Atsushi Suzuki; Yasutaka Miyamoto; Takeo Oku. 2020. "Electronic structures, spectroscopic properties, and thermodynamic characterization of sodium- or potassium-incorporated CH3NH3PbI3 by first-principles calculation." Journal of Materials Science 55, no. 23: 9728-9738.

Journal article
Published: 01 January 2020 in REVIEWS ON ADVANCED MATERIALS SCIENCE
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The crystal structures of various types of perovskite halide compounds were summarized and described. Atomic arrangements of these perovskite compounds can be investigated by X-ray diffraction and transmission electron microscopy. Based on the structural models of basic perovskite halides, X-ray and electron diffractions were calculated and discussed to compare with the experimental data. Other halides such as elemental substituted or cation ordered double perovskite compounds were also described. In addition to the ordinary 3-dimensional perovskites, low dimensional perovskites with 2-, 1-, or 0-dimensionalities were summarized. The structural stabilities of the perovskite halides could be investigated computing the tolerance and octahedral factors, which can be useful for the guideline of elemental substitution to improve the structures and properties, and several low toxic halides were proposed. For the device conformation, highly crystalline-orientated grains and dendritic structures can be formed and affected the photo-voltaic properties. The actual crystal structures of perovskite halides in the thin film configuration were studied by Rietveld analysis optimizing the atomic coordinates and occupancies with low residual factors. These results are useful for structure analysis of perovskite halide crystals, which are expected to be next-generation solar cell materials.

ACS Style

Takeo Oku. Crystal structures of perovskite halide compounds used for solar cells. REVIEWS ON ADVANCED MATERIALS SCIENCE 2020, 59, 264 -305.

AMA Style

Takeo Oku. Crystal structures of perovskite halide compounds used for solar cells. REVIEWS ON ADVANCED MATERIALS SCIENCE. 2020; 59 (1):264-305.

Chicago/Turabian Style

Takeo Oku. 2020. "Crystal structures of perovskite halide compounds used for solar cells." REVIEWS ON ADVANCED MATERIALS SCIENCE 59, no. 1: 264-305.

Journal article
Published: 31 December 2019 in Heliyon
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A photovoltaic power generation system suitable for mobile applications was developed. A SiC integrated converter with the maximum power point tracking circuit provided the smallest photovoltaic inverter in ~200 W level. The SiC-based inverter exhibited a peak direct current (DC)-alternating current (AC) conversion efficiency higher than that of conventional Si inverters. A Li-ion laminated battery was mounted in the same housing as the inverter. The weight of entire system containing spherical Si solar cell panels was well below 6 kg. Continuous operation measurements of this system were carried out using four solar cell modules connected in parallel under irradiation by natural sunlight. The total inverter efficiencies under realistic operation conditions were slightly decreased compared with the DC-AC converter values because of loss by the maximum power point tracking device. Even under unstable weather conditions, the system provided power stability without ripples. The behaviors of the output powers of the solar cell, storage battery, and inverter modules were analyzed as a function of the solar radiation power density. The substantial efficiencies of the solar cell modules were dependent on the weather conditions and were approximately 10% on cloudy days. The present compact photovoltaic power generation system with SiC device and spherical Si solar cells is viable for sub kW-class inverter.

ACS Style

Yuji Ando; Takeo Oku; Masashi Yasuda; Kazufumi Ushijima; Hiroshi Matsuo; Mikio Murozono. Dependence of electric power flow on solar radiation power in compact photovoltaic system containing SiC-based inverter with spherical Si solar cells. Heliyon 2019, 6, e03094 .

AMA Style

Yuji Ando, Takeo Oku, Masashi Yasuda, Kazufumi Ushijima, Hiroshi Matsuo, Mikio Murozono. Dependence of electric power flow on solar radiation power in compact photovoltaic system containing SiC-based inverter with spherical Si solar cells. Heliyon. 2019; 6 (1):e03094.

Chicago/Turabian Style

Yuji Ando; Takeo Oku; Masashi Yasuda; Kazufumi Ushijima; Hiroshi Matsuo; Mikio Murozono. 2019. "Dependence of electric power flow on solar radiation power in compact photovoltaic system containing SiC-based inverter with spherical Si solar cells." Heliyon 6, no. 1: e03094.

Journal article
Published: 03 October 2019 in Chemical Physics Letters
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Perovskite solar cells, in which decaphenylcyclopentasilane (DPPS) layers were formed on the surface of the CH3NH3PbI3 perovskite layer, were fabricated and characterized. The photovoltaic properties were improved by controlling the annealing temperature of the perovskite layer. For perovskite layers annealed at high temperatures of ~200 °C, the perovskite crystals were densely formed and the surface coverage of the perovskite layer was improved. The DPPS-laminated devices suppressed the formation of PbI2 crystals and the stability was improved by the DPPS layer.

ACS Style

Masaya Taguchi; Atsushi Suzuki; Takeo Oku; Naoki Ueoka; Satoshi Minami; Masanobu Okita. Effects of annealing temperature on decaphenylcyclopentasilane-inserted CH3NH3PbI3 perovskite solar cells. Chemical Physics Letters 2019, 737, 136822 .

AMA Style

Masaya Taguchi, Atsushi Suzuki, Takeo Oku, Naoki Ueoka, Satoshi Minami, Masanobu Okita. Effects of annealing temperature on decaphenylcyclopentasilane-inserted CH3NH3PbI3 perovskite solar cells. Chemical Physics Letters. 2019; 737 ():136822.

Chicago/Turabian Style

Masaya Taguchi; Atsushi Suzuki; Takeo Oku; Naoki Ueoka; Satoshi Minami; Masanobu Okita. 2019. "Effects of annealing temperature on decaphenylcyclopentasilane-inserted CH3NH3PbI3 perovskite solar cells." Chemical Physics Letters 737, no. : 136822.