Measuring system for time and spatially resolved optical spectroscopy

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In the field of semiconductor optics, time-resolved photoluminescence spectroscopy is an established, informative and robust approach for non-destructive investigations of the dynamics of optical excitations. The technique is based on the optical excitation of semiconductor materials by a short-pulse laser source and the recording of the temporally resolved luminescence signal, which is performed by a streak camera in the measuring station applied for here. The planned setup will be used in the research of several groups of the departments of physics and chemistry at the Philipps-Universität Marburg. For the semiconductor spectroscopy group, the instrument will be the central apparatus for experimental work. The junior research group investigates organic and perovskite semiconductors, as well as hybrid materials and heterostructures. Time-resolved luminescence spectroscopy is employed to characterize the relationships between structural and optical properties, transport mechanisms of optical excitations, and charge and energy transfer processes at internal interfaces. Furthermore, the interactions between optical excitations and structural relaxation are of interest, leading to localization effects and the formation of polarons or excimers. The instrument will also be used by the Semiconductor Photonics group for the characterization of two-dimensional semiconductors to provide complementary information on terahertz emission characteristics from which the underlying charge carrier dynamics can be inferred. Moreover, there are other research groups in the applicant's environment in whose research the proposed large-scale instrument can be used to great advantage, especially for characterizing novel compounds such as luminophores or organic-inorganic hybrid materials. Correlating the spectrally and spatially resolved information with excitation dynamics is of outstanding importance for many of the topics mentioned above. On the one hand, the diffusion behavior of excited charge carriers or excitons can be traced and correlated with spectral information, allowing for the development robust kinetic models. On the other hand, luminescence dynamics can also be correlated with local microstructure, for example to characterize heterogeneous materials. In certain cases, the targeted experiments require a very precise setting of the excitation conditions and the dynamic processes take place on a variety of time scales, depending on the material. Therefore, there are high demands regarding the flexibility of the setup, which will be purchased modularly from different suppliers. The system applied for strengthens the available methodology for the investigation of dynamic processes in a variety of materials and bears the potential for fruitful usage in future collaborative projects.