AbstractThe photoswitchable MOlecular Solar Thermal (MOST) energy storage systems that are capable of exhibiting high energy storage densities are found to suffer from the poor cyclability, the use of less abundant UV light of the solar spectrum, or reduced charging/discharging rates and poor photoconversions in solid states. Herein, we have designed and readily synthesized a novel set of para‐thioalkyl substituted arylazoisoxazoles, that undergo high trans‐cis and cis‐trans photoconversions under visible light, and show fast charging/discharging and impressive cyclability. Remarkably, the presence of C6‐or C10‐thioalkyl chainin photochromes permitted reversible solid‐liquid phase transition with the formation of cis‐enriched charged states by 400 nm light irradiation and trans‐enriched discharged states by 530 nm light at various temperatures (10–35 °C). The solid‐to‐liquid phase transition enabled storage of the latent heat in addition to the isomerization energy, resulting in a high net energy storage density of 189–196 J/g, which are substantially higher than that of many recently reported azobenzene‐based MOST compounds (100–161 J/g). Using a high‐resolution infrared camera, we further demonstrated that a brief irradiation of green light can be employed to readily release the trapped photon energy as heat. Our results suggest that the arylazoisoxazole with C6‐thioalkyl chain at para‐position can serve as an effective and eco‐friendly photoliquefiable MOST material.
摘要可光开关的分子太阳能热(MOST)储能系统能够表现出较高的储能密度,但其存在循环性差、需要使用较少的太阳光谱紫外光、充放电速率降低以及固态光电转换能力差等问题。在此,我们设计并轻松合成了一组新型对硫代烷基取代芳基偶氮异噁唑,它们在可见光下可发生高反式和顺式光转换,并显示出快速充电/放电和令人印象深刻的可循环性。值得注意的是,在不同温度(10-35 °C)下,C6-或 C10-硫代烷基链光色素的存在允许可逆的固液相转变,在 400 纳米光照射下形成顺式富集带电态,在 530 纳米光照射下形成反式富集放电态。固-液相变除了能储存异构化能量外,还能储存潜热,因此净能量储存密度高达 189-196 J/g,大大高于最近报道的许多偶氮苯基 MOST 化合物(100-161 J/g)。通过使用高分辨率红外相机,我们进一步证明了利用绿光的短暂照射就能轻易地将捕获的光子能量作为热量释放出来。我们的研究结果表明,在对位上带有 C6-硫代烷基链的芳基偶氮异噁唑可以作为一种有效且环保的可光降解 MOST 材料。