Papers - SUZUKI Atsushi

Photovoltaic Characteristics of CH3NH3PbI3 Perovskite Solar Cells Added with Ethylammonium Bromide and Formamidinium Iodide Reviewed

Nishi K., Oku T., Kishimoto T., Ueoka N., Suzuki A.

Coatings   10 ( 4 )   2020.4

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© 2020 by the authors. 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.

DOI： 10.3390/coatings10040410

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Photovoltaic Characteristics of CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> Perovskite Solar Cells Added with Ethylammonium Bromide and Formamidinium Iodide Reviewed

Nishi K, Oku T, Kishimoto T, Ueoka N, Suzuki A

Coatings   10 ( 4 )   2020.4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Coatings  

© 2020 by the authors. 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.

DOI： 10.3390/coatings10040410

Electronic structures, spectroscopic properties, and thermodynamic characterization of sodium- or potassium-incorporated CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> by first-principles calculation Reviewed

Suzuki A., Miyamoto Y., Oku T.

Journal of Materials Science   2020.1

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© 2020, Springer Science+Business Media, LLC, part of Springer Nature. 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.

DOI： 10.1007/s10853-020-04511-y

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Electronic structures, spectroscopic properties, and thermodynamic characterization of sodium- or potassium-incorporated CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> by first-principles calculation Reviewed

Suzuki A, Miyamoto Y, Oku T

Journal of Materials Science   2020.1

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© 2020, Springer Science+Business Media, LLC, part of Springer Nature. 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.

DOI： 10.1007/s10853-020-04511-y

Effects of annealing temperature on decaphenylcyclopentasilane-inserted CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> perovskite solar cells Reviewed

Taguchi M., Suzuki A., Oku T., Ueoka N., Minami S., Okita M.

Chemical Physics Letters   737   2019.12

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© 2019 Elsevier B.V. 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.

DOI： 10.1016/j.cplett.2019.136822

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Effects of annealing temperature on decaphenylcyclopentasilane-inserted CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> perovskite solar cells Reviewed

Taguchi M, Suzuki A, Oku T, Ueoka N, Minami S, Okita M

Chemical Physics Letters   737   2019.12

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Chemical Physics Letters  

© 2019 Elsevier B.V. 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.

DOI： 10.1016/j.cplett.2019.136822

Fabrication and characterization of perovskite type solar cells using phthalocyanine complexes Reviewed

Suzuki A., Okumura H., Yamasaki Y., Oku T.

Applied Surface Science   488   586 - 592   2019.9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Applied Surface Science  

© 2019 Elsevier B.V. Perovskite compound-based solar cells using metal free phthalocyanine, silicon phthalocyanine or germanium naphthalocyanine complexes were fabricated and characterized for improving the photovoltaic performance. Additive effects of metal free phthalocyanine, silicon phthalocyanine or germanium naphthalocyanine complexes into the methyl ammonium‑lead-halide perovskite layer on the photovoltaic properties were investigated. The slight addition of the silicon phthalocyanine into the perovskite layer caused suppression of defect and pinhole in the surface layer, which had the best photovoltaic performance. The phthalocyanine complexes play an important role for improving the crystal growth, carrier generation and diffusion without carrier recombination and trapping near the defect and pinhole in the perovskite layer.

DOI： 10.1016/j.apsusc.2019.05.305

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Fabrication and characterization of perovskite type solar cells using phthalocyanine complexes Reviewed

Suzuki A, Okumura H, Yamasaki Y, Oku T

Applied Surface Science   488   586 - 592   2019.9

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© 2019 Elsevier B.V. Perovskite compound-based solar cells using metal free phthalocyanine, silicon phthalocyanine or germanium naphthalocyanine complexes were fabricated and characterized for improving the photovoltaic performance. Additive effects of metal free phthalocyanine, silicon phthalocyanine or germanium naphthalocyanine complexes into the methyl ammonium‑lead-halide perovskite layer on the photovoltaic properties were investigated. The slight addition of the silicon phthalocyanine into the perovskite layer caused suppression of defect and pinhole in the surface layer, which had the best photovoltaic performance. The phthalocyanine complexes play an important role for improving the crystal growth, carrier generation and diffusion without carrier recombination and trapping near the defect and pinhole in the perovskite layer.

DOI： 10.1016/j.apsusc.2019.05.305

Fabrication and evaluation of K-doped MA<inf>0.8</inf>FA<inf>0.1</inf>K<inf>0.1</inf>PbI<inf>3</inf>(Cl) perovskite solar cells Reviewed

Machiba H., Oku T., Kishimoto T., Ueoka N., Suzuki A.

Chemical Physics Letters   730   117 - 123   2019.9

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© 2019 Elsevier B.V. Perovskite solutions that were doped with potassium (K) salts (CH3NH3)0.8(HC(NH2)2)0.1K0.1PbI3 (MA0.8FA0.1K0.1PbI3(Cl)) were used to fabricate perovskite solar cells. The addition of the K salts resulted in fine grained perovskite crystals that were separated by very small gaps. These materials were used to fabricate solar cells that improved short circuit current densities, which resulted in an enhanced conversion efficiency, compared with standard materials. The K occupied the (CH3NH3)/(HC(NH2) defects within the perovskite crystals, which caused the lattice constant to increase. Additionally, the presence of K in the perovskite solutions promoted the growth of grains within the perovskite crystals.

DOI： 10.1016/j.cplett.2019.05.050

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Fabrication and evaluation of K-doped MA<inf>0.8</inf>FA<inf>0.1</inf>K<inf>0.1</inf>PbI<inf>3</inf>(Cl) perovskite solar cells Reviewed

Machiba H, Oku T, Kishimoto T, Ueoka N, Suzuki A

Chemical Physics Letters   730   117 - 123   2019.9

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© 2019 Elsevier B.V. Perovskite solutions that were doped with potassium (K) salts (CH3NH3)0.8(HC(NH2)2)0.1K0.1PbI3 (MA0.8FA0.1K0.1PbI3(Cl)) were used to fabricate perovskite solar cells. The addition of the K salts resulted in fine grained perovskite crystals that were separated by very small gaps. These materials were used to fabricate solar cells that improved short circuit current densities, which resulted in an enhanced conversion efficiency, compared with standard materials. The K occupied the (CH3NH3)/(HC(NH2) defects within the perovskite crystals, which caused the lattice constant to increase. Additionally, the presence of K in the perovskite solutions promoted the growth of grains within the perovskite crystals.

DOI： 10.1016/j.cplett.2019.05.050

First-principles calculation study of electronic structures of alkali metals (Li, K, Na and Rb)-incorporated formamidinium lead halide perovskite compounds Reviewed

A. Suzuki, T. Oku

Applied Surface Science   483   912 - 921   2019.7

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier   Participation form：Joint(The main charge)  

Electronic structures of alkali metals (Li, Na, K or Rb)-incorporated formamidinium lead halide perovskite compounds were investigated by first-principles calculation. The conduction band were supplied with electrons from energy levels at 2s, 3s, 4s and 5s orbital of alkali metal to energy levels at 6p orbital of Pb atom in the perovskite crystal. Deviation of charge distribution in the perovskite crystal promoted the photo-induced charge generation, electron correlation and electron-lattice interaction as phonon effectiveness. The chemical shifts of 127 I-NMR in the perovskite crystal were originated in a slight perturbation of the coordination structure with nuclear quadruple interaction based on the electric field gradient. The slight incorporation of alkali metal near the ligand structure decreased the enthalpy with the Gibbs free-energy by contribution of the entropy due to the P–I stretching vibration.

DOI： 10.1016/j.apsusc.2019.04.049

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First-principles calculation study of electronic structures of alkali metals (Li, K, Na and Rb)-incorporated formamidinium lead halide perovskite compounds Reviewed

A. Suzuki, T. Oku

Applied Surface Science   483   912 - 921   2019.7

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Electronic structures of alkali metals (Li, Na, K or Rb)-incorporated formamidinium lead halide perovskite compounds were investigated by first-principles calculation. The conduction band were supplied with electrons from energy levels at 2s, 3s, 4s and 5s orbital of alkali metal to energy levels at 6p orbital of Pb atom in the perovskite crystal. Deviation of charge distribution in the perovskite crystal promoted the photo-induced charge generation, electron correlation and electron-lattice interaction as phonon effectiveness. The chemical shifts of 127 I-NMR in the perovskite crystal were originated in a slight perturbation of the coordination structure with nuclear quadruple interaction based on the electric field gradient. The slight incorporation of alkali metal near the ligand structure decreased the enthalpy with the Gibbs free-energy by contribution of the entropy due to the P–I stretching vibration.

DOI： 10.1016/j.apsusc.2019.04.049

Effects of guanidinium addition to CH3NH3PbI3−xClx perovskite photovoltaic devices Reviewed International journal

Taku Kishimoto, Atsushi Suzuki, Naoki Ueoka, Takeo Oku

Journal of the Ceramic Society of Japan   127 ( 7 )   491 - 497   2019.7

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Language：English   Publishing type：Research paper (scientific journal)   Publisher： The Ceramic Society of Japan   Participation form：Joint(The main charge)  

DOI： https://doi.org/10.2109/jcersj2.18214

Effects of guanidinium addition to CH3NH3PbI3−xClx perovskite photovoltaic devices Reviewed

Taku Kishimoto, Atsushi Suzuki, Naoki Ueoka, Takeo Oku

Journal of the Ceramic Society of Japan   127 ( 7 )   491 - 497   2019.7

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Additive Effect of Formamidinium Chloride in Methylammonium Lead Halide Compound-Based Perovskite Solar Cells Reviewed

Suzuki A., Kato M., Ueoka N., Oku T.

Journal of Electronic Materials   48 ( 6 )   3900 - 3907   2019.6

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© 2019, The Minerals, Metals & Materials Society. Perovskite compound-based solar cells using methylammonium lead iodine (CH3NH3I), lead iodine (PbI2) and formamidinium chloride (HC(NH2)2Cl: FACl) were fabricated and characterized for improving the photovoltaic performance. Additive effects of FACl into the methylammonium-lead-halide perovskite layer on the photovoltaic properties were investigated. The slight additive of FACl into the perovskite layer promoted the crystal nucleation and growth with the monodispersed domain as the surface morphologies, which improved the photovoltaic performance with external quantum efficiency over ultra-violet–visible–near infrared region. The photovoltaic performance was improved by the surface morphology with the monodispersed crystal growth in the homogenous phase for promoting the photo-induced carrier-generation and extension of the carrier diffusion with suppression of the carrier recombination and trapping near pinholes, defects, voids, cracks and interface between the domains in the perovskite layer.

DOI： 10.1007/s11664-019-07153-2

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Additive Effect of Formamidinium Chloride in Methylammonium Lead Halide Compound-Based Perovskite Solar Cells Reviewed

Suzuki A, Kato M, Ueoka N, Oku T

Journal of Electronic Materials   48 ( 6 )   3900 - 3907   2019.6

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© 2019, The Minerals, Metals & Materials Society. Perovskite compound-based solar cells using methylammonium lead iodine (CH3NH3I), lead iodine (PbI2) and formamidinium chloride (HC(NH2)2Cl: FACl) were fabricated and characterized for improving the photovoltaic performance. Additive effects of FACl into the methylammonium-lead-halide perovskite layer on the photovoltaic properties were investigated. The slight additive of FACl into the perovskite layer promoted the crystal nucleation and growth with the monodispersed domain as the surface morphologies, which improved the photovoltaic performance with external quantum efficiency over ultra-violet–visible–near infrared region. The photovoltaic performance was improved by the surface morphology with the monodispersed crystal growth in the homogenous phase for promoting the photo-induced carrier-generation and extension of the carrier diffusion with suppression of the carrier recombination and trapping near pinholes, defects, voids, cracks and interface between the domains in the perovskite layer.

DOI： 10.1007/s11664-019-07153-2

Effects of KBr or KCl addition to CH3NH3PbI3(Cl) photovoltaic devices Reviewed International journal

Hayato Machiba, Takeo Oku and Atsushi Suzuki

AIP Conference Proceedings   2067   020009-1 - 7   2019.1

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AIP Publishing   Participation form：Joint(The vice charge)  

Fabrication and Characterization of Perovskite Solar Cells added with Zinc Phthalocyanine to Active Layer Reviewed International journal

Atsushi Suzuki, Yuto Hayashi, Yasuhiro Yamasaki and Takeo Oku

AIP Conference Proceedings   2067   020010-1 - 6   2019.1

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Effectsof TiO2 nanoparticleswithdifferent sizes on the performance of CH3NH3PbI3-xClx solar cells Reviewed International journal

Naoki Ueoka, Takeo Oku, Atsushi Suzuki, Hiroki Sakamoto, Masahiro Yamada, Satoshi Minami, and Masanobu Okita

AIP Conference Proceedings   2067   020001-1 - 10   2019.1

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Effects of poly(methyl methacrylate) addition to perovskite photovoltaic devices Reviewed International journal

Masaya Taguchi, Atsushi Suzuki, Naoki Ueoka, and Takeo Oku

AIP Conference Proceedings   2067   020018-1 - 8   2019.1

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