Smart heat transport control by solid-liquid composite system

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K20897
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Hasegawa Tetsuya 東京大学, 大学院理学系研究科(理学部), 教授 (10189532)
• Project Period (FY): 2020-07-30 – 2022-03-31
• Keywords: 熱輸送制御 / ハイブリッド材料 / 相転移

Outline of Final Research Achievements

Toward the realization of smart heat transport control devices, we mainly investigated phase transition materials. Among them, the preparation of free-standing films of Ti3O5 is a major achievement; although Ti3O5 is known as a material that undergoes a phase transition upon various external stimuli, there have been few examples of thin films or single crystals of Ti3O5. In this study, free-standing single-crystal thin films of Ti3O5 were obtained by depositing a film on a water-soluble sacrificial layer and then dissolving and exfoliating the sacrificial layer. We also focused on the search for systems in which the electronic properties can be significantly controlled by the introduction of fluorine. As a result, we found metal-insulator transitions in Ni-based and Ru-based layered perovskites by the introduction of fluorine. We also initiated the preparation of nanostructures of inorganic materials in ionic liquids.

Free Research Field

固体化学

Academic Significance and Societal Importance of the Research Achievements

金属－絶縁体転移を示す材料の熱制御への利用はこれまでも模索されてきたが、フォノンによる熱伝導の寄与が大きく、かつ薄膜の場合には基板を流れる熱流が加わるため、十分なON/OFF比を確保できなかった。本研究では、フォノンによる熱輸送を低減できる可能性のあるナノ薄膜化と、基板からの剥離によるフリースタンディング膜作製を技術基盤とし、これに相転移の外場制御とイオン液体とのハイブリッド化を組み合わせることで、熱輸送制御に新たなコンセプトをもたらすものである。本研究の成果はデバイス実現に向けて、その端緒を開いたものといえる。