标题： 通过原子模拟揭示量子点中的激子陷阱动力学和非辐射损失路径 显示英文标题

标题： Unraveling Exciton Trap Dynamics and Nonradiative Loss Pathways in Quantum Dots via Atomistic Simulations

摘要： 胶体量子点中的表面缺陷是非辐射损耗的主要来源，但导致激子捕获和复合的微观机制仍然不清楚。 在这里，我们基于原子电子计算开发了一个模型哈密顿量，以研究含有由未配位硫原子引入的单一空穴陷阱的CdSe/CdS核/壳QD中的激子动力学。 通过系统地改变缺陷深度和重组能，我们揭示了由缺陷引起的激子态如何介导能量弛豫路径。 我们的模拟显示，单一局域化缺陷可以诱导丰富的激子态光谱，从而导致多种动力学状态，从缓慢的能量失谐捕获到快速的通过带间缺陷态的级联弛豫。 至关重要的是，我们量化了缺陷引起的极化子移动和激子-声子耦合如何支配高效辐射发射与快速非辐射衰减之间的平衡。 这些见解澄清了缺陷辅助损失通道的微观起源，并提出了通过表面和缺陷工程调整QD光电性能的途径。 显示英文摘要

摘要： Surface defects in colloidal quantum dots are a major source of nonradiative losses, yet the microscopic mechanisms underlying exciton trapping and recombination remain elusive. Here, we develop a model Hamiltonian based on atomistic electronic calculations to investigate exciton dynamics in CdSe/CdS core/shell QDs containing a single hole trap introduced by an unpassivated sulfur atom. By systematically varying the defect depth and reorganization energy, we uncover how defect-induced excitonic states mediate energy relaxation pathways. Our simulations reveal that a single localized defect can induce a rich spectrum of excitonic states, leading to multiple dynamical regimes, from slow, energetically off-resonant trapping to fast, cascaded relaxation through in-gap defect states. Crucially, we quantify how defect-induced polaron shifts and exciton-phonon couplings govern the balance between efficient radiative emission and rapid nonradiative decay. These insights clarify the microscopic origin of defect-assisted loss channels and suggest pathways for tailoring QD optoelectronic properties via surface and defect engineering.