论文标题
激子 - Phonon耦合分子聚集体的激子相干长度的统一定义
Unified definition of exciton coherence length for exciton-phonon coupled molecular aggregates
论文作者
论文摘要
激子相干长度（ECL）是表征分子骨料中激子的性质的重要概念，用于光合作用，有机光伏和发光二极管。通过电子还原密度矩阵的方差或纯度，已通过多种方式定义了ECL。但是，我们发现这些定义无法就激子辐射衰减效率提出单调关系，因为当将激子 - phonon耦合置于考虑方面时。我们通过振荡器优势的总和提出了对ECL的统一定义。使用数值准确的时间依赖性矩阵产物状态形式主义应用于一维系统和二维系统中的分子骨料，应用于一维系统的分子聚集体，我们发现我们的ECL定义在辐射效率方面表现出单调关系，并且可以作为兴奋剂相干性的有效和统一描述。我们进一步预测，二维聚集体可以在有限温度下显示最大的超级增强（SRE），这与先前对SRE- $ 1/T $行为的知识不同。
Exciton coherence length (ECL) is an essential concept to characterize the nature of exciton in molecular aggregates for photosynthesis, organic photovoltaics, and light-emitting diodes. ECL has been defined in a number of ways through the variance or purity of the electronic reduced density matrix. However, we find that these definitions fail to present a monotonic relationship with respect to the exciton radiative decay efficiency as it should be when exciton-phonon couplings are taken into accounts. We propose a unified definition of ECL by virtue of sum rule of oscillator strengths. Using the numerically accurate time-dependent matrix product states formalism applied to Frenkel-Holstein models for molecular aggregates in both one- and two-dimensional system, we find our ECL definition exhibits a monotonic relationship with respect to the radiative efficiency and can serve as an efficient and unified description for exciton coherence. We further predict that the two-dimensional aggregates can display maximum superradiance enhancement (SRE) at finite temperature, different from the previous knowledge of SRE-$1/T$ behavior.
