飯久保 智 (イイクボ サトシ)

IIKUBO Satoshi

写真a

職名

准教授

研究室住所

福岡県北九州市若松区ひびきの2-4

取得学位 【 表示 / 非表示

  • 名古屋大学 -  博士(理学)  2005年03月

学内職務経歴 【 表示 / 非表示

  • 2014年04月
    -
    継続中

    九州工業大学   大学院生命体工学研究科   生体機能応用工学専攻   准教授  

 

論文 【 表示 / 非表示

  • Suppression of charge carrier recombination in lead-free tin halide perovskite via lewis base post-treatment

    Kamarudin M., Hirotani D., Wang Z., Hamada K., Nishimura K., Shen Q., Toyoda T., Iikubo S., Minemoto T., Yoshino K., Hayase S.

    Journal of Physical Chemistry Letters    10 ( 17 ) 5277 - 5283   2019年09月  [査読有り]

     概要を見る

    Copyright © 2019 American Chemical Society. Lead-free tin perovskite solar cells (PSCs) show the most promise to replace the more toxic lead-based perovskite solar cells. However, the efficiency is significantly less than that of lead-based PSCs as a result of low open-circuit voltage. This is due to the tendency of Sn2+ to oxidize into Sn4+ in the presence of air together with the formation of defects and traps caused by the fast crystallization of tin perovskite materials. Here, post-treatment of the tin perovskite layer with edamine Lewis base to suppress the recombination reaction in tin halide PSCs results in efficiencies higher than 10%, which is the highest reported efficiency to date for pure tin halide PSCs. The X-ray photoelectron spectroscopy data suggest that the recombination reaction originates from the nonstoichiometric Sn:I ratio rather than the Sn4+:Sn2+ ratio. The amine group in edamine bonded the undercoordinated tin, passivating the dangling bonds and defects, resulting in suppressed charge carrier recombination.

    DOI Scopus

  • Relationship between Lattice Strain and Efficiency for Sn-Perovskite Solar Cells

    Nishimura K., Hirotani D., Kamarudin M., Shen Q., Toyoda T., Iikubo S., Minemoto T., Yoshino K., Hayase S.

    ACS Applied Materials and Interfaces    11 ( 34 ) 31105 - 31110   2019年08月  [査読有り]

     概要を見る

    Copyright © 2019 American Chemical Society. In the composition of Q0.1(FA0.75MA0.25)0.9SnI3, Q is replaced with Na+, K+, Cs+, ethylammonium+ (EA+), and butylammonium+ (BA+), respectively, and the relationship between actually measured lattice strain and photovoltaic performances is discussed. The lattice strain evaluated by the Williamson-hall plot of X-ray diffraction data decreased as the tolerance factor was close to one. The efficiency of the Sn-perovskite solar cell was enhanced as the lattice strain decreased. Among them, EA0.1(FA0.75MA0.25)0.9SnI3 having lowest lattice strain gave the best result of 5.41%. Because the carrier mobility increased with a decrease in the lattice strain, these lattice strains would disturb carrier mobility and decrease the solar cell efficiency. Finally, the results that the efficiency of the SnGe-perovskite solar cells was gradually enhanced from 6.42 to 7.60% during storage, was explained by the lattice strain relaxation during the storage.

    DOI Scopus

  • First-Principles Study of Chemical Driving Force for Face Centered Cubic to Hexagonal Close Packed Martensitic Transformation in Hydrogen-Charged Iron

    Kuroki Y., Kawano S., Iikubo S., Ohtani H., Koyama M., Tsuzaki K.

    Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science    50 ( 7 ) 3019 - 3023   2019年07月  [査読有り]

     概要を見る

    © 2019, The Minerals, Metals & Materials Society and ASM International. This study uses first-principles calculations to investigate the effect of hydrogen on the chemical driving force of the transformation of iron from the face centered cubic (FCC) to hexagonal close packed (HCP) phase. The minimum energy path from FCC to HCP phases shows that FCC becomes stable with increasing hydrogen content. Furthermore, the energy difference between the FCC and HCP phases is observed to be smaller in Fe2H than in Fe throughout the temperature region. These results clearly explain the observed anomalous suppression of the martensitic transformation in the hydrogen-charged steel.

    DOI Scopus

  • Experimental and Theoretical Elucidation of Electrochemical CO <inf>2</inf> Reduction on an Electrodeposited Cu <inf>3</inf> Sn Alloy

    Morimoto M., Takatsuji Y., Iikubo S., Kawano S., Sakakura T., Haruyama T.

    Journal of Physical Chemistry C    123 ( 5 ) 3004 - 3010   2019年02月  [査読有り]

     概要を見る

    © 2019 American Chemical Society. The reaction selectivity of an electrode catalyst can be modulated by regulating its crystal structure, and the modified electrode may show different CO 2 reduction selectivity from that of its constituent metal. In this study, we investigated the mechanisms of the electrochemical CO 2 reduction on an electrodeposited Cu 3 Sn alloy by experimental and theoretical analyses. The electrodeposited Cu 3 Sn alloy electrode showed selectivity for CO production at all the applied potentials, and HCOOH production increased with an increase in the applied potential. In particular, hydrocarbon generation was well suppressed on Cu 3 Sn(002). To understand this selectivity change in electrochemical CO 2 reduction, we conducted density functional theory calculations for the reaction on the Cu 3 Sn(002) surface. According to the theoretical analysis, the Cu sites in Cu 3 Sn(002) contributed more to the stabilization of H∗, COOH∗, and CO∗ as compared with the Sn sites. Furthermore, the results indicated that Cu 3 Sn(002) decreased the surface coverage of reaction intermediates such as H∗, COOH∗, and CO∗. We believe that these effects promoted CO∗ desorption while suppressing H 2 generation, CO∗ protonation, and C-C bond formation. The results also suggested that the surface Sn concentration significantly affected the reaction selectivity for HCOOH production from CO 2 .

    DOI Scopus

  • Key factor for the transformation from Hcp to 18R-type long-period stacking ordered structure in Mg alloys

    Matsushita M., Nagata T., Bednarcik J., Nishiyama N., Kawano S., Iikubo S., Kubota Y., Morishita R., Irifune T., Yamasaki M., Kawamura Y., Enoki M., Ohtani H.

    Materials Transactions    60 ( 2 ) 237 - 245   2019年01月  [査読有り]

     概要を見る

    ©2018 The Japan Institute of Metals and Materials. Cast Mg 85 Y 9 Zn 6 has an 18R-type LPSO structure. However, Mg 85 Y 9 Zn 6 recovered after being subjected to a loading pressure of 7 GPa at 973 K shows a fine dual-phase structure composed of a face-centered cubic (fcc) structure showing a superlattice (D0 3 ), as well as a hexagonal close-packed structure (hcp:2H). The D0 3 /hcp structure transformed to 18R-type LPSO during heating at ambient pressure. In this research, the transformation process from the D0 3 /hcp structure to 18R-type LPSO structure was discussed by means of in situ XRD and first-principles calculation. At first, lattice volume of 2H increased with an increase in the temperature, because of the Zn and Y emitted from the D0 3 phase into the 2H lattice. After the volume expansion of 2H lattice, the structure collapsed due to insert of random stacking faults (SFs). Then, a formation of 18R-type LPSO structure occurred. Based on a first-principles calculation for pure Mg, volume expansion of the 2H lattice causes the transformation to an 18R structure. Furthermore, the results of free energy calculations for the hcp and fcc structures in the MgYZn ternary system show that the segregation of Y and Zn atoms on SFs occurs by the Suzuki effect. These segregated Y and Zn atoms in SF layers, which have a local fcc structure, create a synergy between the stacking and chemical modulations. Present result insists that the volume increase of 2H lattice takes place first, and then the transformation from the hcp structure to 18R stacking occurs. [doi:10.2320/matertrans.M2018213]

    DOI Scopus

全件表示 >>

口頭発表・ポスター発表等 【 表示 / 非表示

  • Lattice dynamics of all-inorganic perovskite CsSnX 3 (X = Cl, Br, and I): A first-principles study

    Shoya Kawano,Satoshi Iikubo

    PSCO-2019  2019年09月  -  2019年09月    PSCO

  • Effect of substitution on the stability in Tin based Perovskite: First-Principles study

    Kumiko Yamamoto,Satoshi Iikubo

    PSCO-2019  2019年09月  -  2019年09月    PSCO

  • 鉛フリー有機無機ペロブスカイトの電子状態計算

    井手 敦子,山本 久美子,奥村 崚,飯久保 智,早瀬 修二

    2019年第80回応用物理学会秋季学術講演会  2019年09月  -  2019年09月    応用物理学会

  • 進化的アルゴリズムによる有機無機ペロブスカイト化合物の安定構造探索と熱電特性

    山本 久美子,飯久保 智

    2019年第80回応用物理学会秋季学術講演会  2019年09月  -  2019年09月    応用物理学会

  • 2次元構造を持つハロゲン化ペロブスカイトの熱電特性計算

    成田 昴宇,山本 久美子,飯久保 智

    2019年第80回応用物理学会秋季学術講演会  2019年09月  -  2019年09月    応用物理学会

全件表示 >>

科研費獲得実績 【 表示 / 非表示

  • 初期構造に依存しない安定構造探索法の開発

    若手研究(B)

    研究期間:  2013年04月  -  2016年03月

    研究課題番号:  25820324

  • 実空間局所磁気構造解析法によるスピネル化合物の異常磁気相関の解明

    若手研究(B)

    研究期間:  2009年04月  -  2011年03月

    研究課題番号:  21740239

 

担当授業科目 【 表示 / 非表示

  • 2019年度  環境材料設計

  • 2019年度  計算材料学Ⅰ

  • 2018年度  環境材料設計

  • 2018年度  計算材料学Ⅰ

  • 2017年度  計算材料学Ⅰ

全件表示 >>