Structure-property relation in highly luminescent organic semiconductors with high charge carrier mobilities

有机半导体(OSCs)是一种化合物，含有碳、氢和可能的其他元素，并表现出依赖于温度的导电性。它们在有机发光二极管(OLED)等光电子器件中得到了应用。OLED的工作原理是基于材料界面处电子和未占据电子态(空穴)的辐射复合。为了优化这种器件的性能，材料的两个属性具有很高的相关性。首先，高载流子迁移率，确保所有注入的电荷载流子到达界面进行复合。这就要求材料具有很高的结构有序性，并且只有很少的缺陷会分散和减缓载流子的运动。第二，有效的发射，这意味着在理想情况下，所有注入的电荷载流子应该重新组合并有助于光的发射。初步实验证明，结构性质不仅对载流子迁移率，而且对发光都很重要。这种结构性质的关系还没有完全从根本上理解。因此，本项目将集中研究材料的结构、化学组成、载流子迁移率与一类表现出高载流子迁移率和高效发光的OSC的光学性质，特别是发射之间的相互作用。这些OSC的可能应用将在设备中进行测试。

Organic semiconductors (OSCs) are compounds, containing carbon, hydrogen and possibly other elements and exhibit temperature dependent electrical conductivity. They find applications in optoelectronic devices such as organic light emitting diodes (OLEDs). The working principle of OLEDs is based on the radiative recombination of electrons and unoccupied electronic states (holes) at an interface in the material. In order to optimize the performance of such a device, two properties of the material are of high relevance. First, a high charge carrier mobility, assuring that all injected charge carriers reach an interface to recombine. This requires a material with high structural order and only a few defects which may scatter and slow down the motion of the charge carriers. Second, an efficient emission, which means, in the ideal case all injected charge carriers should recombine and contribute to the emission of light. Preliminary experiments demonstrated the importance of the structural properties not only for the charge carrier mobility but also for the emission of light. This structure property relation is not yet completely understood from a fundamental point of view.Therefore, the project will focus on a study of the interplay between structure of the material, chemical composition, charge carrier mobilities and optical properties, in particular emission, of a class of OSCs which exhibit high charge carrier mobilities and highly efficient luminescence. Possible applications of these OSCs will be tested in devices.