Femtosecond pump-probe spectroscopy of excited states in conjugated polymers for organic electronics

为了进一步发展用于光电应用的共轭聚合物，例如有机发光二极管（oled）、场效应晶体管、有机激光器和光伏电池，需要完全了解它们的光物理性质。因此，必须应用各种不同的实验技术，从时间分辨光致发光光谱（覆盖从飞秒到秒的时间范围）到电荷载流子迁移率测量，再到有机电子器件中所研究材料的应用和表征。预期的研究项目旨在了解一系列新型阶梯型共轭聚合物的光物理性质，这些聚合物是有机电子学中非常有前途的候选者。特别是，需要对这些材料进行飞秒泵浦探测光谱和光诱导吸收（PIA）研究，以研究源自单线态和三重态激子以及极化子（自由基阴离子/阳离子）的激发态吸收，它们在有机电子器件中起着重要作用，严重限制了共轭聚合物在有机固体激光器中的应用。有机电子器件的制备，特别是用于有机固体激光的反馈结构以及有机太阳能电池的制备，计划将光物理表征结果与电子器件的性质联系起来，并建立可靠的结构-性质关系。

The further development of conjugated polymers for optoelectronic applications, for example organic light emitting diodes (OLEDs), field-effect transistors, organic lasers and photovoltaics requires a complete understanding of their photophysical properties. Therefore, a variety of different experimental techniques has to be applied with experiments ranging from time-resolved photoluminescence spectroscopy covering the time range from femtoseconds up to seconds, over charge carrier mobility measurements towards application and characterisation of the investigated materials in organic electronic devices. The intended research project aims for an understanding of the photophysical properties of a novel series of ladder-type conjugated polymers which are highly promising candidates for organic electronics. In particular, femtosecond pump-probe spectroscopy and photoinduced absorption (PIA) studies shall be conducted on these materials to study excited state absorption originating from singlet and triplet excitons as well as polarons (radical anions / cations), which are known to play an important role in organic electronic devices and can severely limit the applicability of conjugated polymers in organic solid state lasers. Preparation of organic electronic devices, especially feedback structures for organic solid state lasing as well as organic solar cells is planned to correlate the results of the photophysical characterisation with properties in electronic devices and to develop reliable structure-property relationships.