Photoliquefiable Ionic Crystals: A Phase Crossover Approach for Photon Energy Storage Materials with Functional Multiplicity |
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| Authors: | Keita Ishiba Dr. Masa‐aki Morikawa Chie Chikara Dr. Teppei Yamada Katsunori Iwase Mika Kawakita Prof. Dr. Nobuo Kimizuka |
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| Affiliation: | 1. Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto‐oka Nishi‐ku, Fukuoka 819‐0395 (Japan);2. JST CREST, Honcho 4‐1‐8, Kawaguchi, Saitama 332‐0012 (Japan);3. DENSO CORPORATION, 500‐1 Minamiyama, Komenoki‐cho, Nisshin, Aichi 470‐0111 (Japan) |
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| Abstract: | Ionic crystals (ICs) of the azobenzene derivatives show photoinduced IC–ionic liquid (IL) phase transition (photoliquefaction) upon UV‐irradiation, and the resulting cis‐azobenzene ILs are reversibly photocrystallized by illumination with visible light. The photoliquefaction of ICs is accompanied by a significant increase in ionic conductivity at ambient temperature. The photoliquefaction also brings the azobenzene ICs further significance as photon energy storage materials. The cis‐IL shows thermally induced crystallization to the trans‐IC phase. This transition is accompanied by exothermic peaks with a total ΔH of 97.1 kJ mol?1, which is almost double the conformational energy stored in cis‐azobenzene chromophores. Thus, the integration of photoresponsive ILs and self‐assembly pushes the limit of solar thermal batteries. |
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| Keywords: | energy storage ionic liquids phase transitions photochemistry self‐assembly |
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