Institut für Physik and Center of Interface Science, Carl von Ossietzky Universität, Oldenburg, Germany.
Bremen Center for Computational Materials Science, University of Bremen, Bremen, Germany.
Nat Nanotechnol. 2021 Jan;16(1):63-68. doi: 10.1038/s41565-020-00791-2. Epub 2020 Nov 16.
Conical intersections (CoIns) of multidimensional potential energy surfaces are ubiquitous in nature and control pathways and yields of many photo-initiated intramolecular processes. Such topologies can be potentially involved in the energy transport in aggregated molecules or polymers but are yet to be uncovered. Here, using ultrafast two-dimensional electronic spectroscopy (2DES), we reveal the existence of intermolecular CoIns in molecular aggregates relevant for photovoltaics. Ultrafast, sub-10-fs 2DES tracks the coherent motion of a vibrational wave packet on an optically bright state and its abrupt transition into a dark state via a CoIn after only 40 fs. Non-adiabatic dynamics simulations identify an intermolecular CoIn as the source of these unusual dynamics. Our results indicate that intermolecular CoIns may effectively steer energy pathways in functional nanostructures for optoelectronics.
锥形交叉点（CoIns）在多维势能表面中普遍存在，并控制着许多光引发的分子内过程的途径和产率。这种拓扑结构可能涉及到聚集分子或聚合物中的能量传递，但尚未被发现。在这里，我们使用超快二维电子光谱（2DES），揭示了在与光伏相关的分子聚集体中存在分子间 CoIns。超快、亚 10fs 的 2DES 跟踪了在光强态上振动波包的相干运动，以及在仅 40fs 后通过 CoIns 突然跃迁到暗态的过程。非绝热动力学模拟确定了分子间 CoIns 是这些异常动力学的来源。我们的结果表明，分子间 CoIns 可能有效地控制功能纳米结构中的能量途径，用于光电。
