Ultrafast spectroscopic techniques provide a multidimensional perspective on photo-induced processes in excitonic materials by offering spectral, temporal, and/or spatial resolution. This allows for a comprehensive analysis of processes, including exciton generation, relaxation, recombination, diffusion, dissociation, intersystem crossing, coherent coupling, energy transfer, charge transport in solid films, and spin-selective dynamics such as chirality induced spin selectivity. Mechanistic understanding of these phenomena, especially in complex media such as semiconductor heterostructures, hybrid materials, and chiral materials, is crucial for advancing applications such as LEDs, photovoltaics, photoredox reactions, lasing, and opto-spintronic applications.

The method spectrum for these investigations is vast and includes pump (dump/pump-) probe transient absorption spectroscopy (UV-vis, XUV, IR, X-ray, THZ), multidimensional electronic and vibrational spectroscopy, and time-resolved impedance, cathodoluminescence, chiroptical and microscopy techniques. #SpecEx highlights ultrafast spectroscopic investigations of the photophysical, photochemical, and optoelectronic properties of excitonic materials, novel ultrafast methods, and their respective interpretations and tools.