发表机构
University of Rostock（罗斯托克大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过实验与理论结合，发现苝红微晶中观察到的两个戴维多跃迁不属同一戴维多对，其分裂不直接反映库仑耦合，并证实高迁移率单线态Frenkel激子主导非相干跳跃输运。
AI 中文摘要
我们利用实验和理论方法研究了晶胞包含八个分子的苝红微晶的激子性质。在标称的八个戴维多跃迁中，仅实验观察到两个，其表观分裂为610 cm$^{-1}$，这一数值由基于密度泛函理论参数化的Frenkel-Holstein激子模型合理重现。基于对称性的本征态分析表明，观察到的两个跃迁不属于同一戴维多对，因此该分裂并不直接反映晶胞内的库仑耦合。局部激发的复杂混合导致主导跃迁形成J型带，通过增加光谱重叠促进激子转移。与此图像一致，发射的时间相关单光子计数和超快瞬态吸收光谱表明，动力学由高迁移率的单线态Frenkel激子主导。从实验提取的激子迁移率与动力学蒙特卡洛模拟获得的结果非常吻合，支持非相干跳跃输运的图像。
英文摘要
We investigate the excitonic properties of perylene red microcrystals, whose unit cell contain eight molecules, using both experimental and theoretical methods. Only two of the nominal eight Davydov transitions are experimentally observed, with an apparent splitting of 610 cm$^{-1}$ that is reasonably reproduced by a Frenkel-Holstein exciton model parametrized from density functional theory. A symmetry-based analysis of the eigenstates reveals that the two observed transitions do not belong to the same Davydov pair, so the splitting does not directly report on the Coulomb coupling within the unit cell. The complex mixture of local excitations produces a J-like band for the dominant transitions, favouring exciton transfer through increased spectral overlap. Consistent with this picture, time-correlated single-photon counting of the emission and ultrafast transient absorption spectroscopy show that the dynamics is dominated by highly mobile singlet Frenkel excitons. The exciton mobility extracted from experiment agrees very well with that obtained from Kinetic Monte Carlo simulations, supporting a picture of incoherent hopping transport.
Comments11 pages, 7 figures, supplement
