Ultrafast Dynamics of Electronic Excitations in Single Conjugated Polymer Chains

单共轭聚合物链中电子激发的超快动力学

• 批准号: 260342502
• 负责人: Professor Dr. Richard Hildner
• 金额: --
• 依托单位: Lehrstuhl für Experimentalphysik II (Optoelektronik weicher Materie)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/260342502?language=en
• 关键词: Ultrafast; Dynamics; Electronic; Excitations; Single

The ultrafast transport dynamics of electronic excitations is a key process in the initial steps of solar energy conversion in organic photovoltaic devices based on p-conjugated polymers. However, the electronic structure of this material class, and in particular the ultrafast (sub-picosecond) formation and transport dynamics of electronic excitations is still not entirely clear and controversially discussed. Although these processes can in principle be investigated by conventional ultrafast ensemble spectroscopy, the development of a detailed understanding is hampered by the large structural and electronic heterogeneity of conjugated polymers. In this project we will therefore employ ultrafast single-molecule spectroscopy to study the properties of a prototypical and technologically important system, oligo- and polythiophenes, on a molecular scale. We aim at resolving the femtosecond formation of fundamental electronic excitations as well as their subsequent transport dynamics within single thiophene chains by measurements as a function of the thiophene chain length, their local environment, and the temperature. We want to retrieve the time scales, the relaxation energies, and the relaxation pathways of electronic excitations during their initial formation and localisation. Moreover, we will investigate the various factors that influence the intra-chain energy transport, such as the precise chain conformation, the electronic interactions, as well as the role of and the coupling to the local chain environment. A particular focus will be to resolve potential coherent transport on ultrashort (< 250 fs) time scales and to identify the relevant parameters that impact on the coherence lifetime.

电子激发的超快输运动力学是p-共轭聚合物有机光伏器件太阳能转换初始阶段的关键过程。然而，这类材料的电子结构，特别是电子激发的超快（亚皮秒）形成和传输动力学仍然不完全清楚，并有争议的讨论。虽然这些过程原则上可以通过传统的超快系综光谱进行研究，但共轭聚合物的大结构和电子异质性阻碍了详细了解的发展。因此，在这个项目中，我们将采用超快单分子光谱学来研究一个典型的和技术上重要的系统，低聚和聚噻吩，在分子尺度上的属性。我们的目标是解决飞秒形成的基本电子激发，以及随后的传输动力学在单个噻吩链的噻吩链长度的函数，其本地环境，和温度的测量。我们希望检索的时间尺度，弛豫能量，和电子激发在其初始形成和本地化的弛豫路径。此外，我们将研究影响链内能量传递的各种因素，例如精确的链构象，电子相互作用，以及局部链环境的作用和耦合。一个特别的重点将是解决潜在的相干传输超短（< 250 fs）的时间尺度，并确定相关参数的相干寿命的影响。