Probing exciton dynamics with time resolved x-ray spectroscopy

本研究的目的是利用时间分辨X射线能谱进一步了解有机半导体中的激子动力学。将要研究的材料包括：聚噻吩类、Y6和Y7，后两种材料是非常有前景的实际光伏材料，因为它们表现出高的转换效率和直接的电荷分离，可以产生自由电荷，而不需要在施主-受主异质结构中实现。该项目将进行高时间分辨率(&lt；10fS)时间分辨X射线光谱分析仪器的必要研究和开发。这将涉及优化高次谐波产生源，以用于研究这些材料中的S L边、CL L边以及C和N Kedge，同时还将优化可见-近红外亚飞秒泵浦脉冲。将寻求XFELs(包括闪光、瑞士FEL、费米、LCLS和欧洲XFEL)的更多束流时间，以扩大研究范围，以捕捉更高能量原子边缘的动力学，例如O-K和F-K边缘。

The goal of this research is to further the understanding of exciton dynamics in organic semiconductors using time-resolved x-ray spectroscopy. The materials to be studied will include: Polythiophene, Y6 and Y7 the latter two being very promising materials as real world photovoltaics due to demonstrated high conversion efficiency and direct charge separation of the exciton to generate free charges without the need to implement in a donor-acceptor heterostructure. The project will conduct necessary research and development of an apparatus for high time resolution (< 10 fs) time resolved x-ray spectroscopy. This will involve optimisation of a high harmonic generation source for studies around the S L edge, Cl L edge and C and N Kedges in these materials, and in parallel the optimisation of visible-near IR sub-fs pump pulses. Further beamtime at XFELs (including FLASH, Swiss FEL, FERMI, LCLS and European XFEL) will be sought in order to extend the studies to capture the dynamics at higher energy atomic edges e.g. O K and F K edges.