2023 Fiscal Year Annual Research Report
Polar-axis-deformation induced molecular pyroelectrics for waste heat harvesting
| Project/Area Number |
22K14655
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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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| Keywords | supramolecule / polarity / structural flexibility / pyroelectricity |
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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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