In the fields of optoelectronics and photochemistry there is growing interest in studying the response to optical excitation of organic molecules, films, and interfaces, as these systems are of fundamental relevance for the development of the next generation of environmentally sustainable optoelectronic devices and catalysts. Thanks to the constant advances in the generation of X-ray pulses it is now possible to observe such photo-induced dynamics with chemical selectivity, using time-resolved X-ray photoemission spectroscopy. The X-ray pulses that are required for such kind of experiments are provided by FEL, HHG and synchrotron facilities, but the latter are often overlooked due to their larger pulse lengths, which limit the temporal resolution to roughly a hundred picoseconds. In this talk, I will discuss the experimental challenges that are usually encountered in such measurements. In particular, the limiting factor is often represented by the excitation density: the fraction of atoms/molecules pumped by the optical pulse is typically in the 1-5% range, requiring a high count rate to discriminate the photo-induced signal from the background. I will then present some recent results obtained at the ANCHOR-SUNDYN endstation of the ALOISA beamline at Elettra, demonstrating the opportunities of time-resolved photoemission at synchrotrons. Such experiments might provide valuable data regarding sample stability, required fluences, and the presence of long-lived effects, in support of further FEL-based measurements.
