The evolution of the excited-state manifold in organic D/A aggregates (e.g., the prototypical P3HT/PCBM) is investigated through a bottom-up approach via first-principles calculations. We show how the excited-state energies, the charge transfer (CT) states, and the electron–hole density distributions are strongly influenced by the size, the orientation, and the position (i.e., on-top versus on-edge phases) of P3HT/PCBM domains. We discuss how the structural order influences the excited-state electronic structure, providing an atomistic interpretation of the photophysics of organic blends. We show how the simultaneous presence of on-top and on-edge phases does not alter the optical absorption spectrum of the blend but does affect the photophysics. Photovoltaic processes such as (i) the simultaneous charge generation obtained from hot and cold excitations, (ii) the instantaneous and delayed charge separation, and (iii) the pump–push–probe charge generation can be interpreted based on our study.

中文翻译：

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有机光伏中的冷热电荷转移机制：对供体/受体界面激发态的见解

通过第一性原理通过自下而上的方法研究了有机D / A聚集体（例如原型P3HT / PCBM）中激发态流形的演化。我们展示了激发态能量，电荷转移（CT）态和电子-空穴密度分布如何受到电子束的大小，方向和位置（即顶相和边沿相）的强烈影响P3HT / PCBM域。我们讨论了结构顺序如何影响激发态电子结构，从而提供了有机混合物光物理的原子学解释。我们展示了顶相和边缘相的同时存在如何不会改变共混物的光吸收光谱，但会影响光物理。