研究者データベース
清水 俊樹SHIMIZU Toshikiシミズ トシキ
| ■所属部署名 | 工学研究院 先端物理工学部門 | |||
| ■職名 | 助教 | |||
Last Updated :2024/09/25
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
担当授業科目
科学研究費助成事業
論文
- 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 - 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