Tang Shuxin, Zhang Yating, Xia Jun, Qi Jing, Tang Fan, Zhai Fei, Dong Liqi
Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy, Zhejiang Shuren University, Hangzhou 310021, China.
College of Environment, Zhejiang University of Technology, 18 Chaowang RD, Hangzhou 310014, China.
Molecules. 2025 May 27;30(11):2333. doi: 10.3390/molecules30112333.
The development of photoactive molecules for photothermal energy storage is a focus of research in solar energy utilization technology. Azobenzene photoswitch has emerged as a promising candidate for solar energy conversion and storage due to its unique photoisomerization characteristics. Nonetheless, a majority of azobenzene-based molecular photothermal systems have a significant drawback: they depend on ultraviolet light for -to- isomerization to store photon energy rather than visible light, which seriously hinders the development of azobenzene photoswitch in practical solar energy utilization applications. In this study, an azobenzene photothermal molecule that can effectively store visible-light photon energy was design and synthesized, which includes a --chlorinated azo structure as the "head" part and an alkyl chain at -position as the "tail" part. The ultraviolet-visible and H NMR spectrum indicated that the obtained --chlorinated azobenzene photothermal molecule could effectively absorb and store photon energy under 550 nm irradiation and release the stored energy upon 430 nm light irradiation. The storage energy density of the charged azobenzene photothermal molecule was determined to be 13.50 kJ/mol through differential scanning calorimetry and 28.21 kJ/mol via density functional theory theoretical calculations. This discrepancy was ascribed to the 64% Z-isomer yield harvesting during the charging process. Furthermore, the obtained --chlorinated azobenzene exhibited long-term energy storage (approximately 11 days of half-life) and cyclic stability (100 cycles). Notably, the -isomer of --chlorinated azobenzene exhibited a high degree of supercooling, which may be advantageous for use in extremely low-temperature environments.
用于光热能存储的光活性分子的开发是太阳能利用技术研究的一个重点。偶氮苯光开关因其独特的光异构化特性，已成为太阳能转换和存储的一个有前途的候选者。尽管如此，大多数基于偶氮苯的分子光热系统有一个显著缺点：它们依赖紫外光进行反式到顺式的异构化来存储光子能量，而不是可见光，这严重阻碍了偶氮苯光开关在实际太阳能利用应用中的发展。在本研究中，设计并合成了一种能有效存储可见光光子能量的偶氮苯光热分子，其包括一个对氯偶氮结构作为“头部”部分，以及在对位的烷基链作为“尾部”部分。紫外可见光谱和核磁共振氢谱表明，所得到的对氯偶氮苯光热分子在550nm光照下能有效吸收和存储光子能量，并在430nm光照下释放存储的能量。通过差示扫描量热法测定带电偶氮苯光热分子的储能密度为13.50kJ/mol，通过密度泛函理论理论计算为28.21kJ/mol。这种差异归因于充电过程中64%的Z-异构体产率收获。此外，所得到的对氯偶氮苯表现出长期储能（半衰期约11天）和循环稳定性（100次循环）。值得注意的是，对氯偶氮苯的顺式异构体表现出高度过冷，这可能有利于在极低温环境中使用。
