We present a model for the triplet-triplet annihilation in organic phosphorescent host-guest systems that considers the effect of the energetic disorder on the kinetics of the annihilation. Nonequilibrium (time-dependent) transport of the triplets that arises from the progressive relaxation of triplets in the energy landscape is taken into account in the model. Triplet excitons are considered to move between the guest sites (dye molecules) via the thermally activated tunneling mechanism; the annihilation step, however, takes place through the Förster mechanism. Based on the model developed, and by calculating the time evolution of the triplet concentration, we investigate the effect of the various parameters on the effective annihilation coefficient. At low dye concentrations, it is shown that relaxation of the triplets is not completed during their lifetimes, and therefore, the annihilation process occurs entirely in the nonequilibrium. We also address the competition between two pathways for the annihilation process: single-step, long-range annihilation, and diffusion-assisted annihilation. By a quantitative comparison with experimental data reported in the literature, we demonstrate certain conditions in which there is a considerable contribution from the diffusion to the total annihilation rate. The model presented in this work can also be used for the excitons that diffuse by the Förster mechanism.

中文翻译：

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能量紊乱对有机半导体三重态-三重态an灭的影响

我们提出了在有机磷光宿主系统中三重态-三重态let灭的模型，该模型考虑了高能紊乱对an灭动力学的影响。在模型中考虑了三重态的非平衡（随时间变化）的运输，这是由于三重态在能量环境中逐渐松弛引起的。三重态激子被认为是通过热激活隧穿机制在客体（染料分子）之间移动的。但是，an灭步骤是通过Förster机制进行的。基于开发的模型，并通过计算三重态浓度的时间演变，我们研究了各种参数对有效an灭系数的影响。在低染料浓度下 结果表明，三重态在其一生中并未完全松弛，因此，hil灭过程完全在不平衡中发生。我们还解决了two灭过程的两种途径之间的竞争：单步，远程an灭和扩散辅助an灭。通过与文献报道的实验数据进行定量比较，我们证明了某些条件，其中扩散对总an灭率有很大贡献。这项工作中介绍的模型也可以用于由Förster机制扩散的激子。和扩散辅助的an灭。通过与文献报道的实验数据进行定量比较，我们证明了某些条件，其中扩散对总an灭率有很大贡献。这项工作中介绍的模型也可以用于由Förster机制扩散的激子。和扩散辅助的an灭。通过与文献报道的实验数据进行定量比较，我们证明了某些条件，其中扩散对总an灭率有很大贡献。这项工作中提出的模型也可以用于通过Förster机制扩散的激子。