Diketopyrrolopyrroles (DPPs) have attracted attention for their potential applications in organic photovoltaics due to their tunable optical properties and charge‐carrier mobilities. In this study, we investigate the excited‐state dynamics of a DPP dimer using time‐dependent density functional theory (TDDFT) and nonadiabatic molecular dynamics simulations. Our results reveal a near‐barrierless hydrogen migration state intersection that facilitates ultrafast internal conversion with a lifetime of about 400 fs, leading to fluorescence quenching. Electronic density analysis along the relaxation pathway confirms a hydrogen atom transfer mechanism. These findings highlight the critical role of state intersections in the photophysical properties of DPP dimers, providing new insights for the design of functionalized DPP systems aimed at suppressing nonradiative decay for enhanced performance in photovoltaic applications.

中文翻译：

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二酮吡咯吡咯二聚体的超快动力学


二酮吡咯吡咯 （DPP） 因其可调谐的光学特性和电荷载流子迁移率而因其在有机光伏中的潜在应用而引起关注。在这项研究中，我们使用时间依赖性密度泛函理论 （TDDFT） 和非绝热分子动力学模拟研究了 DPP 二聚体的激发态动力学。我们的结果揭示了一种近乎无屏障的氢迁移态交集，它促进了超快内部转换，寿命约为 400 fs，导致荧光猝灭。沿弛豫途径的电子密度分析证实了氢原子转移机制。这些发现强调了状态交集在 DPP 二聚体光物理特性中的关键作用，为功能化 DPP 系统的设计提供了新的见解，旨在抑制非辐射衰变以增强光伏应用的性能。