Tailoring organic molecular structure to achieve singlet fission for photovoltaic applications

太阳能是可再生能源领域的关键资源，但由于效率受到根本上的限制，它并没有充分发挥其潜力。单线态裂变有可能通过将一个高能量光子转化为两个低能量光子来显著提高光伏光收集的效率，从而超越Shockley-Queisser极限。尽管进行了近十年的研究，但这项技术的进步一直受到限制，因为能够满足单线态裂变发生的严格能量要求的合适分子的选择有限，甚至更少的分子表现出最佳的分子包装和光稳定性，使该过程能够在现实世界中应用。靛蓝染料（工业靛蓝染料的衍生物），由于其优越的光稳定性，高消光系数和理想的预测三重态能量，是非常有吸引力的单线态裂变候选者。虽然在能量上可行，但先前的研究表明，它们的非理想分子构象阻碍了促进单线态裂变所需的有效分子间轨道重叠。该项目旨在与化学家合作，阐明是否可以在不牺牲分子稳定性的情况下，对cibalackrot的化学结构进行简单、明智的改变，从而产生难以捉摸的单线态裂变势。描述潜在的单线态裂变动力学对于证明改进的分子结构如何积极影响这些分子的光物理是至关重要的。这将通过使用广泛的尖端技术来实现，例如超高速飞秒瞬态吸收光谱，电子顺磁共振，以及x射线衍射测量。这种交叉检验的目的是通过对分子堆积结构的分析来补充对光物理的理解。这将使我们对分子设计的结果有更广泛的了解，并验证我们可以定制分子结构来利用单线态裂变用于可再生能源应用和更清洁的环境未来的假设。

Solar energy is a key resource in the renewable energy sector, yet it does not fulfil its potential due to fundamentally restricted efficiency. Singlet fission has the potential to significantly enhance the efficiency of photovoltaic light harvesting beyond this Shockley-Queisser limit by transforming one higher energy photon into two lower energy photons. Despite almost a decade of research, the progress of this technology has been hindered by the limited selection of suitable molecules that can satisfy the strict energetic requirements for singlet fission to occur, with even fewer exhibiting optimal molecular packing and photostability for the process to be viable for real-world application. Cibalackrots (derivatives of industrial indigo dyes), are highly attractive candidates for singlet fission due to their superior photostability, high extinction coefficient and ideal predicted triplet energy. While energetically viable, previous works suggest their non-ideal molecular conformation prevents efficient intermolecular orbital overlap required to facilitate singlet fission. This project aims to collaborate with chemists to elucidate if simple, judicious alterations in chemical structure of Cibalackrots can give rise to the elusive singlet fission potential desired without sacrificing molecular stability.Characterising the underlying singlet fission dynamics is crucial in demonstrating how an improved molecular structure may positively affect the photophysics of these molecules. This will be achieved by using a wide range of cutting-edge techniques, such as ultra-fast femtosecond transient absorption spectroscopy, and electron paramagnetic resonance, alongside with X-Ray diffraction measurements. This cross-examination will aim to complement the understanding of the photophysics with analysis of the molecular packing structure. This will give a broader understanding of the consequences of molecular design, and test the hypothesis that we can tailor molecular structure to harness singlet fission for renewable energy application and a cleaner environmental future.