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).
Angew Chem Int Ed Engl. 2015 Jan 26;54(5):1532-6. doi: 10.1002/anie.201410184. Epub 2014 Dec 5.
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.
偶氮苯衍生物的离子晶体（ICs）在紫外光照射下表现出光致 IC-离子液体（IL）相转变（光致液化），所得顺式偶氮苯 IL 可通过可见光照射可逆地光晶化。ICs 的光致液化伴随着环境温度下离子电导率的显著增加。光致液化还使偶氮苯 IC 进一步成为光子能量存储材料。顺式 IL 表现出热诱导结晶为反式 IC 相。这种转变伴随着放热峰，总焓变为 97.1 kJ/mol(-1)，几乎是顺式偶氮苯发色团中储存的构象能的两倍。因此，光响应 ILs 和自组装的结合推动了太阳能热电池的极限。
