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，并表现出与温度相关的导电性。它们在光电器件如有机发光二极管（oled）中得到了应用。oled的工作原理是基于材料界面上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，材料的两个性质是高度相关的。首先，高载流子迁移率，确保所有注入的载流子到达一个界面重新组合。这需要一种结构有序度高、缺陷少的材料，这些缺陷可能会分散并减慢载流子的运动。第二，高效发射，这意味着在理想情况下，所有注入的载流子都应该重新组合并有助于发光。初步实验表明，结构特性不仅对载流子迁移率有重要影响，而且对光的发射也有重要影响。从基本观点来看，这种结构性质关系还没有完全被理解。因此，该项目将重点研究材料结构、化学成分、载流子迁移率和光学性质之间的相互作用，特别是一类具有高载流子迁移率和高效发光的OSCs的发射。这些OSCs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.