Zähringer Till J B, Perez Lopez Nico, Schulte Robin, Schmitz Matthias, Ihmels Heiko, Kerzig Christoph
Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
Department of Chemistry-Biology, and Center of Micro- and Nanochemistry and (Bio)Technology (Cμ), University of Siegen, Adolf-Reichwein-Str. 2, 57068, Siegen, Germany.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202414733. doi: 10.1002/anie.202414733. Epub 2024 Nov 2.
Norbornadiene-based photoswitches have emerged as promising candidates for harnessing and storing solar energy, holding great promise as a viable solution to meet the growing energy demands. Despite their potential, the effectiveness of their direct photochemical conversion into the resulting quadricyclanes has room for improvement owing to (i) moderate quantum yields, (ii) poor overlap with the solar spectrum and (iii) photochemical back reactions. Herein, we present an approach to enhance the performance of such molecular solar thermal energy storage (MOST) systems through the triplet-sensitized conversion of aryl-substituted norbornadienes. Our study combines deep spectroscopic analyses, irradiation experiments, and quantum mechanical calculations to elucidate the energy transfer mechanism and inherent advantages of the resulting MOST systems. We demonstrate remarkable quantum yields using readily available sensitizers under both LED and solar light irradiation, significantly surpassing those achieved through direct excitation with photons of higher energy. In contrast to the conventional approach, light-induced back reactions of the high-energy products do not play any role, allowing quantitative switching within minutes. These results not only underscore the potential of triplet-sensitized MOST systems to leverage the high energy storage capabilities of multistate photoswitches but they might also stimulate the broader usage of sensitization strategies in photochemical energy conversion.
基于降冰片二烯的光开关已成为利用和存储太阳能的有前景的候选者，有望成为满足不断增长的能源需求的可行解决方案。尽管它们具有潜力，但由于（i）量子产率适中，（ii）与太阳光谱的重叠性差以及（iii）光化学逆反应，其直接光化学转化为四环烷的效率仍有提升空间。在此，我们提出一种通过芳基取代的降冰片二烯的三线态敏化转化来提高此类分子太阳能热能存储（MOST）系统性能的方法。我们的研究结合了深入的光谱分析、辐照实验和量子力学计算，以阐明所得MOST系统的能量转移机制和固有优势。我们展示了在LED和太阳光照射下使用现成的敏化剂可实现的显著量子产率，大大超过了通过用更高能量的光子直接激发所达到的量子产率。与传统方法不同，高能产物的光致逆反应不起任何作用，可在数分钟内实现定量切换。这些结果不仅强调了三线态敏化MOST系统利用多态光开关的高储能能力的潜力，还可能刺激光化学能量转换中敏化策略的更广泛应用。
