Li Zhendong, Hernández Federico J, Salguero Christian, Lopez Steven A, Crespo-Otero Rachel, Li Jingbai
Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic University, Shenzhen, 518055, People's Republic of China.
Department of Chemistry, University College London, London, WC1H0AJ, UK.
Nat Commun. 2025 Jan 30;16(1):1194. doi: 10.1038/s41467-025-56480-y.
Crystalline pentacene is a model solid-state light-harvesting material because its quantum efficiencies exceed 100% via ultrafast singlet fission. The singlet fission mechanism in pentacene crystals is disputed due to insufficient electronic information in time-resolved experiments and intractable quantum mechanical calculations for simulating realistic crystal dynamics. Here we combine a multiscale multiconfigurational approach and machine learning photodynamics to understand competing singlet fission mechanisms in crystalline pentacene. Our simulations reveal coexisting charge-transfer-mediated and coherent mechanisms via the competing channels in the herringbone and parallel dimers. The predicted singlet fission time constants (61 and 33 fs) are in excellent agreement with experiments (78 and 35 fs). The trajectories highlight the essential role of intermolecular stretching between monomers in generating the multi-exciton state and explain the anisotropic phenomenon. The machine-learning-photodynamics resolved the elusive interplay between electronic structure and vibrational relations, enabling fully atomistic excited-state dynamics with multiconfigurational quantum mechanical quality for crystalline pentacene.
结晶并五苯是一种典型的固态光捕获材料，因为其通过超快单重态裂变，量子效率超过100%。由于时间分辨实验中电子信息不足，以及模拟实际晶体动力学的量子力学计算难以处理，并五苯晶体中的单重态裂变机制存在争议。在这里，我们结合多尺度多组态方法和机器学习光动力学，以了解结晶并五苯中相互竞争的单重态裂变机制。我们的模拟揭示了通过人字纹和平行二聚体中的竞争通道共存的电荷转移介导机制和相干机制。预测的单重态裂变时间常数（61和33飞秒）与实验结果（78和35飞秒）非常吻合。轨迹突出了单体间分子间拉伸在产生多激子态中的重要作用，并解释了各向异性现象。机器学习光动力学解决了电子结构与振动关系之间难以捉摸的相互作用，实现了具有多组态量子力学质量的完全原子激发态动力学，用于结晶并五苯。
