清水　俊樹SHIMIZU Toshikiシミズ　トシキ

業績情報

氏名・連絡先

• 氏名

  シミズ　トシキ, 清水　俊樹, SHIMIZU Toshiki

主たる所属・職名

• 工学研究院　先端物理工学部門, 助教

その他の所属

• 工学部　化学物理工学科

担当授業科目

• 工学基礎実験
  2024年, 教養科目等
• 物理工学実験
  2023年, 専門科目等

科学研究費助成事業

• 若手研究
  簡易液体セルを用いた液中セルロースナノ結晶の in situ TEM 観察
  自 2023年, 至 2027年

論文

• Application of Hilbert-differential phase contrast to scanning transmission electron microscopy
  Iga, Haruka; Shimizu, Toshiki; Minoda, Hiroki
  MICROSCOPY
  OXFORD UNIV PRESS
  We report a novel class of scanning transmission electron microscopy with Hilbert-differential phase contrast (HDP-STEM) that displays nanostructures of thin samples in a topographical manner. A semicircular pi-phase plate (PP) was used as an optical device for manipulating electron waves in HDP-STEM. This is the different design from the Zernike PP used in our previous phase plate STEM (P-STEM), but both must be placed in the front focal plane of the condenser lens. HDP-STEM images of multiwalled carbon nanotubes showed higher contrast than those obtained by conventional bright-field STEM. As the PP of the HDP-STEM is nonsymmetrical, several different images were obtained by changing the detection conditions. A two-dimensional electron detector was also used to remove the scattering contrast component in the same way as with the Zernike PP and obtain an image containing only (differential) phase contrast.
  2024年04月05日, 研究論文（学術雑誌）, 共同, 73, 5, 2050-5698, DOI(公開)(r-map), 414, 421
• Visualization of Tens of Nanometers Spaced Donor: Acceptor Bulk Heterojunctions across Submicrometer-Square Cross Sections of Organic Photovoltaic Cells
  Kumagai, Natsuki; Shimizu, Toshiki; Minoda, Hiroki; Katayama, Mikimasa; Nakao, Satoru; Kaji, Toshihiko
  ACS APPLIED ENERGY MATERIALS
  AMER CHEMICAL SOC
  Controlling the bulk heterojunction (BHJ) structure of organic photovoltaic cells (OPVs) is essential to improving their power conversion efficiency. Visualizing the interfaces of the organic semiconductor domains in BHJs is important for the development of OPVs. However, the evaluation of the BHJ interface structure is often challenging owing to the close proximity of donor and acceptor organic domains, which are typically spaced less than 100 nm for keeping efficient exciton separation at the junction. In this study, a submicrometer-thick OPV composed of metal-free phthalocyanine (H2Pc) as the donor and fullerene (C-60) as the acceptor was adopted to visualize the interface structure of BHJs. This typical combination of donor and acceptor molecules consists of only three elements: H, C, and N. Phase plate scanning transmission electron microscopy (P-STEM) enabled the visualization of the interface structure of the BHJ with a spacing of tens of nanometers across the submicrometer-square cross section of the OPV. Furthermore, a hybrid layer of H2Pc and C-60 was observed to form at the initial stage of the film growth until a critical thickness, followed by the growth of a phase-separated ordered BHJ. This observation clearly demonstrates the significant potential of P-STEM for analyzing organic hybrid materials.
  2023年09月08日, 研究論文（学術雑誌）, 共同, 6, 18, 2574-0962, DOI(公開)(r-map), 9363, 9370
• Time-Resolved Imaging of Stochastic Cascade Reactions over a Submillisecond to Second Time Range at the Angstrom Level
  Shimizu, Toshiki; Lungerich, Dominik; Harano, Koji; Nakamura, Eiichi
  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
  AMER CHEMICAL SOC
  Many chemical reactions, such as multistep catalytic cycles, are cascade reactions in which a series of transient intermediates appear and disappear stochastically over an extended period. The mechanisms of such reactions are challenging to study, even in ultrafast pump-probe experiments. The dimerization of a van der Waals dimer of [60]fullerene producing a short carbon nanotube is a typical cascade reaction and is probably the most frequently studied in carbon materials chemistry. As many as 23 intermediates were predicted by theory, but only the first stable one has been verified experimentally. With the aid of fast electron microscopy, we obtained cinematographic recordings of individual molecules at a maximum frame rate of 1600 frames per second. Using Chambolle total variation algorithm processing and automated cross-correlation image matching analysis, we report on the identification of several metastable intermediates by their shape and size. Although the reaction events occurred stochastically, varying the lifetime of each intermediate accordingly, the average lifetime for each intermediate structure could be obtained from statistical analysis of many cinematographic images for the cascade reaction. Among the shortest-living intermediates, we detected one that lasted less than 3 ms in three independent cascade reactions. We anticipate that the rapid technological development of microscopy and image processing will soon initiate an era of cinematographic studies of chemical reactions and cinematic chemistry.
  2022年06月08日, 研究論文（学術雑誌）, 共同, 144, 22, 0002-7863, DOI(公開)(r-map), 9797, 9805

受賞

• 15th International Symposium on Atomic Level Characterizations for New Materials and Devices '24 (ALC'24)
  15th International Symposium on Atomic Level Characterizations for New Materials and Devices '24 (ALC'24), Excellent Presentation Award
  "Direct observation of nanocomposite materials in an aqueous environment using liquid-cell transmission electron microscopy”
  島根県松江市で行われた国際学会 15th International Symposium on Atomic Level Characterizations for New Materials and Devices '24(ALC'24)で、優れた研究発表を行った若手研究者に対し授与される。
  2024年11月21日
• 公益財団法人 精密測定技術振興財団
  公益財団法人 精密測定技術振興財団 2023年度40周年記念研究助成 表彰
  「画像処理を用いた液中環境下におけるナノ結晶の透過電子顕微鏡サブナノレベル精密測定」
  受賞テーマ「画像処理を用いた液中環境下におけるナノ結晶の透過電子顕微鏡サブナノレベル精密測定」精密測定技術の分野およびその周辺技術に関するテーマとして、精密測定技術振興財団助成審査委員会において、170件以上の募集の中14名しか選出されない2023年度40周年記念研究助成に採択され、贈賞を受けた。
  2024年03月14日