Identification of ultrafast relaxation processes as a major reason for inefficient exciton diffusion in perylene-based organic semiconductors.
Identification of ultrafast relaxation processes as a major reason for inefficient exciton diffusion in perylene-based organic semiconductors.
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确定超快弛豫过程是苝基有机半导体中激子扩散效率低下的主要原因
DOI：
10.1021/ja413115h
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发表时间：
2014
影响因子：
15
通讯作者：
B. Engels
中科院分区：
文献类型：
--
作者：
V. Settels;A. Schubert;M. Tafipolski;W. L. Liu;V. Stehr;A. K. Topczak;J. Pflaum;C. Deibel;R. F. Fink;V. Engel;B. Engels
激子扩散长度（LD）是影响有机光电器件效率的关键参数。它在纳米长度尺度上的限制导致需要复杂的体积异质结太阳能电池，在长期稳定性和可重复性方面存在困难。因此，一个全面的模型提供了对限制激子输运过程的原子理解是非常可取的，并且将在这里为苝基材料提出。我们的模型基于混合方法的模拟，该方法结合了对系统中直接涉及所述过程的部分的高级从头计算，以及包括环境影响的力场。通过与现有实验结果的详细比较，证明了模型的充分性。该模型表明，α-苝四羧基癸二酐（PTCDA）的激子扩散长度较短是由于分子间运动引起的光激发的超快弛豫过程导致激子进一步扩散受到阻碍。由于该机制的效率很大程度上取决于分子的排列和环境，该模型解释了α-PTCDA和二烯二烯之间的差异对材料形态的强烈依赖性。我们的研究结果表明，在苝基材料中，弛豫过程是如何减少的。该模型可推广到其它有机化合物。
The exciton diffusion length (LD) is a key parameter for the efficiency of organic optoelectronic devices. Its limitation to the nm length scale causes the need of complex bulk-heterojunction solar cells incorporating difficulties in long-term stability and reproducibility. A comprehensive model providing an atomistic understanding of processes that limit exciton trasport is therefore highly desirable and will be proposed here for perylene-based materials. Our model is based on simulations with a hybrid approach which combines high-level ab initio computations for the part of the system directly involved in the described processes with a force field to include environmental effects. The adequacy of the model is shown by detailed comparison with available experimental results. The model indicates that the short exciton diffusion lengths of α-perylene tetracarboxylicdianhydride (PTCDA) are due to ultrafast relaxation processes of the optical excitation via intermolecular motions leading to a state from which further exciton diffusion is hampered. As the efficiency of this mechanism depends strongly on molecular arrangement and environment, the model explains the strong dependence ofLDon the morphology of the materials, for example, the differences between α-PTCDA and diindenoperylene. Our findings indicate how relaxation processes can be diminished in perylene-based materials. This model can be generalized to other organic compounds.
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影响因子：
3
作者：
Volker Settels;Wenlan Liu;J. Pflaum;R. Fink;B. Engels
通讯作者：
Volker Settels;Wenlan Liu;J. Pflaum;R. Fink;B. Engels
影响因子：
8.6
作者：
So;Forrest
通讯作者：
So;Forrest
聚（3-己基噻吩）单线态激子的光泵浦诱导载流子生成。
影响因子：
5.7
作者：
Patrick C. Tapping;Tak W. Kee
通讯作者：
Tak W. Kee
影响因子：
27.8
作者：
Kamm, Valentin;Battagliarin, Glauco;Laquai, Frederic
通讯作者：
Laquai, Frederic
DOI：
--
发表时间：
1977
期刊：
影响因子：
--
作者：
C. Shank;E. Ippen;O. Teschke
通讯作者：
O. Teschke