Polar-axis-deformation induced molecular pyroelectrics for waste heat harvesting
| Project/Area Number |
22K14655
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 32020:Functional solid state chemistry-related
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| Research Institution | Hokkaido University |
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Principal Investigator |
黄 瑞康 北海道大学, 電子科学研究所, 助教 (60901296)
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| Project Period (FY) |
2022-04-01 – 2024-03-31
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| Project Status |
Granted (Fiscal Year 2022)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2023: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2022: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
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| Keywords | supramolecule / polarity / structural flexibility / pyroelectricity / Molecular pyroelectrics / Waste heat harvesting / Thermal expansion / Supramolecular crystals |
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| Outline of Research at the Start |
Waste heat recycling has been a huge challenge. One of the most promising solution is recycling them by pyroelectric materials that can generate current during temperature change. This research aims to demonstrate a novel strategy (polar axis deformation) for designing molecular pyroelectrics, and explore their applications for waste heat harvesting. In this research, the design-structure-pyroelectricity relationship will be discussed and prototype of energy harvesting will be made. Results may open up a new area of molecular pyroelectrics design and their application in energy problems.
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| Outline of Annual Research Achievements |
18-crown-6-based supramolecular crystals can exhibit structural flexibility or polarity. For example, nitromethane solvate 18C6 is highly structurally flexible due to Van der Waal interactions between nitromethane and 18C6. Additionally, (4-methoxyanilinium)(18C6)(BF4) shows polarity due to the polar -OCH3 group, allowing the crystal to exhibit piezoelectricity, pyroelectricity, and ferroelectricity. Combining polarity and structural flexibility in an 18C6 crystal is achievable using polar ammoniums with an increased number of -CH2 groups.
Our preliminary study found that that the combination of 3-hydroxyl-adamantane-1-aminium (HADA-OH) with 18C6 produced a crystal that was both structurally flexible and polar due to the -OH group. The polar (HADA-OH)(18C6)ClO4 crystal was found to exhibit both the highest structural flexibility among organic salts and large pyroelectricity (20 times that of PVDF).
This study focuses on HADA-R derivatives (R = H, F, Cl, Br) and examines the effects of different -R groups and counter anions on crystal packing, flexibility, and pyroelectricity. The goal is to establish a relationship between design, structure, and performance in this system and propose a novel strategy for high-performance pyroelectrics for waste heat harvesting.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
We synthesized HADA-R derivatives (R = H, F, Cl, Br) and crystals (HADA-R)(18C6)ClO4. They share similar 1D supramolecular columns, but different properties.
1) The H-compound crystallizes in CmC21 at 353-433 K and Pca21 at 113-333 K. At 253-333 K, both HADA-H and 18C6 undergoes rotational-freezing transition, resulting in large thermal expansions. This compound may exhibit pyroelectricity as designed. 2) The F-compound crystallizes in Cmcm at 373 K, Cmc21 at 253 K, and Pca21 at 133 K. The disordered of NH3 and F in the higher-symmetry Cmcm phase, indicates that HADA-F undergoes flipping motion in the 1D supramolecular column. This compound may be a potential 1D ferroelectric.3) The Cl-compound exhibits polymorphism. One polymorphic crystalize in Cmc21. The other crystallizes in Pbca with reverse-arranged columns. We found that this nonpolar crystal exhibits a planar negative-zero-positive thermal expansion transition due to the rotation-swing-static transition of 18-crown-6. We have submitted these results to Chemistry of Materials. 4) The Br-compound crystallizes in Pmma at 333-413 K and P212121 at 113-313 K. This compound did not show significant thermal expansion, which may be due to the large size Br atom that blocking the 18C6 from molecular motion.
Although we found the rich and interesting physical properties in this series, the progress of research on their pyroelectric properties is slightly behind the research plan due to slow crystal growth and rebuilding for the pyroelectric measurement. We plan to accelerate our research progress in the next year.
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| Strategy for Future Research Activity |
Research plan of this year aims to conduct further studies and organize data on the series of (HADA-R)(18C6) crystals. The following aspects will be covered:
For OH-compounds, research data will be summarized and organized into a manuscript for publication. Concurrently, the method of preparing OH-compounds samples on thin films will be explored and the pyroelectric performance of the prepared thin films will be investigated.
For the substitute compounds,1) Large single crystal samples of H-compounds will be prepared and processed into sizes suitable for measurement to obtain their pyroelectric data. 2) Single crystal samples of F compounds will be prepared to explore their phase transition behavior, dielectric properties, and potential ferroelectricity. 3) Methods to obtain different polymorphs of Cl compounds will be explored. The thermal expansion properties of the Cmc21 crystals will be studied, and the possibility of exhibiting pyroelectricity will be investigated.
Additionally, attempts will be made to replace anions with other monovalent anions such as BF4, PF6, CFSSO3, etc., to explore the effects of anions on this series of crystals and prepare for further exploration of this system.
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Report
(1 results)
Research Products
(6 results)
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[Journal Article] Multifunctional Triggering by Solid-Phase Molecular Motion: Relaxor Ferroelectricity, Modulation of Magnetic Exchange Interactions, and Enhancement of Negative Thermal Expansion2023
Author(s)
Li, Simin; Takahashi, Kiyonori; Huang, Rui-Kang; Xue, Chen; Kokado, Kenta; Hoshino, Norihisa; Akutagawa, Tomoyuki; Nishihara, Sadafumi; Nakamura, Takayoshi
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Journal Title
Chemistry of Materials
Volume: 35
Issue: 6
Pages: 2421-2428
DOI
Related Report
Peer Reviewed
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