【公開日：2024.07.25】【最終更新日：2024.04.04】
課題データ / Project Data
課題番号 / Project Issue Number
23KT0011
利用課題名 / Title
１次元ナノ構造体の規則構造観察およびその電子輸送特性評価
利用した実施機関 / Support Institute
京都大学 / Kyoto Univ.
機関外・機関内の利用 / External or Internal Use
内部利用（ARIM事業参画者以外）/Internal Use (by non ARIM members)
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）量子・電子制御により革新的な機能を発現するマテリアル/Materials using quantum and electronic control to perform innovative functions（副 / Sub）-
キーワード / Keywords
COF, ナノチューブ,電子顕微鏡/ Electronic microscope
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Li Zhuowei
所属名 / Affiliation
京都大学大学院 工学研究科
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
小川 哲也
利用形態 / Support Type
（主 / Main）技術代行/Technology Substitution（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
Two-dimensional conjugated covalent organic framework (COF) sheets were converted in situ via a simple "roll-to-sheet" self-assembly process, replicating the interconvertible carbon allotropes of graphene and carbon nanotubes. Instead of pyrene, azapyrene was used to make COF nanotubes with constant cross-sectional dimensions. By replacing 2,7 carbons in pyrene with nitrogens, the COF's optical and electrical properties changed, reflecting the conjugated 2D sheet's coiled shape. Under ambient circumstances, these nanotubes were semiconducting and offered stable conductive routes along their tubular axes.
実験 / Experimental
Chemical reagents and solvents from Tokyo Chemical Industry (TCI), Sigma Aldrich, Wako, or Alfa Aesar were employed without purification in the synthesis. Aldehyde and amine functionalized ligands were produced and purified according to literature, with yield optimisation.Analysis and spectroscopy were used for characterisation. Tetramethylsilane (TMS) was used as an internal standard to record 1H NMR spectra in various solvents. Direct FT-IR spectra were taken from solid materials. Cu Kα radiation was used for powder X-ray diffraction (PXRD) studies in reflection mode.Using the BET model, nitrogen adsorption isotherms at 77 K were calculated to estimate surface area. Microstructural investigation was done using TEM, whereas diffuse reflectance spectra were collected with a UV-Vis spectrophotometer. The intrinsic charge conductivity of COF sheets was measured using FP-TRMC. Two probes aligned to test static electrical conductivity.
結果と考察 / Results and Discussion
1D nanotubular structure based on the planar conjugated COF (Aza-1PF) was successfully obtained by a facile protocol: rolling-up of COF sheets during in-situ solvothermal condensation reaction. The obtained nanotubes were multi-walled with inter-layer distances of 0.38 nm, which is competitive to the crystalline structure of stacked planar sp2-type 2D conjugated COFs. Unlike the multi-walled nature of Aza-1PF COF nanotubes, the cross-sectional diameter showed almost perfect uniformity at ~40nm, and the coaxial tubular structure was also visualized with a series of microscopy techniques. The electronic structure of the multi-walled nanotubes is well represented by the stacking of the electronic conjugated layers of COFs, as reflected by frontier orbital levels, electronic transitions, and optical/electronic band gaps. Electronic conductivity measurements both in alternating-current and direct-current modes verified semiconducting nature along with 1D tubular structures, exhibiting clear photoconductivity upon excitation of optical band gaps and static electronic conductivity increase upon doping. The doping via vapor diffusion of iodine and protonation of the key building blocks: diazapyrenes was in particular, effective for enhancement and immobilization of electrical conductivity not only within the tubular structure but also inter-linked state of nanotube networks. The present diazapyrene-based nanotubes will be powerful candidates in the future nano-electronic materials.
図・表・数式 / Figures, Tables and Equations
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
- Rolling the 2D Sheets of Conjugated Covalent Organic Framework: Transforming into 1D Electronically Conductive Nanotubes, Zhuowei Li, Takahiro Tsuneyuki, Samrat Ghosh, Takumi Nakazato, Masahiro Odawara, Wakana Matsuda, Masaki Nobuoka, Bin Chen, Rajendra Paitandi, Yusuke Tsutsui, Takayuki Tanaka, Shu Seki, Res. Sq. 2022, https://doi.org/10.21203/rs.3.rs-2332530/v1
- Zhuowei Li, “Self-assembly of 2D Conjugated Covalent Organic Framework into 1D Electronically Conductive Nanotubes”,14th Japan-China Joint Symposium on Conduction and Photoconduction in Organic Solids and Related Phenomena, 名古屋, 2023年12月
特許 / Patents
特許出願件数 / Number of Patent Applications：1件
特許登録件数 / Number of Registered Patents：0件