Aggregation-induced emission (AIE) is a photophysical phenomenon in which weakly luminescent organic chromophores become strongly luminescent in aggregate. The reduced non-radiative decay in aggregates is often cited as the explanation of the AIE. However, the mechanism of competing non-radiative decay pathways is not resolved due to the lack of excited-state structural information in the time-resolved experiments and prohibitively expensive quantum mechanical calculations for photodynamics simulations. We investigated the excited-state dynamics of classic AIE molecules in aggregate, hexaphenylsilole (HPS), tetraphenylsilole (TPS), and cyclooctatetrathiophene (COTh) with a multiscale machine learning accelerated photodynamics approach, integrating neural networks, semiempirical methods, and molecular mechanics. Our simulations predict 263-, 5-, and 12-fold fluorescence enhancement of HPS, TPS, and COTh in good agreement with the experiments (255, 3, and 12). We identified a shared non-radiative decay mechanism involving π_CC torsions in these molecules. These torsions are blocked in aggregate due to intermolecular hindrance between substituents, promoting AIE.

聚集诱导发射（AIE）是一种光物理现象，其中弱发光的有机发色团在聚集时变得强发光。聚集体中非辐射衰变的减少经常被引用作为 AIE 的解释。然而，由于时间分辨实验中缺乏激发态结构信息以及光动力学模拟中昂贵的量子力学计算，竞争性非辐射衰变路径的机制尚未得到解决。我们采用多尺度机器学习加速光动力学方法，结合神经网络、半经验方法和分子力学，研究了聚集体中的经典 AIE 分子、六苯基硅咯 ( HPS )、四苯基硅咯( TPS ) 和环辛四噻吩 ( COTh ) 的激发态动力学。我们的模拟预测HPS、TPS和COTh的荧光增强为 263 倍、5 倍和 12 倍，与实验非常一致（255 倍、3 倍和 12 倍）。我们发现了这些分子中涉及 π _CC扭转的共同非辐射衰变机制。由于取代基之间的分子间阻碍，这些扭转被聚集在一起，从而促进了 AIE。