Light is ubiquitous and light-driven processes are key, e.g., to the perception of the environment by vision and photosynthesis. Furthermore, light-responsive molecules and materials play a quintessential role in addressing central socioeconomic challenges, e.g., transforming our economy towards renewable energies or developing therapeutic approaches to treat cancer. Consequently, research on light-activated molecules and materials, i.e., synthesis as well as functional and mechanistic studies on such systems are intensively researched. This talk will focus on light-driven molecular reactivity of molecules in complex environments, focusing on the excited-state dynamics in molecular intermediates in photocathodes for light-driven hydrogen evolution, in complex electron transfer cascades and photo-activated drugs for cancer therapy. I will discuss our experimental approaches, e.g., combining electrochemistry with ultrafast time-resolved spectroscopy, to investigate the light driven molecular reactivity from new viewpoints and highlight implications for photocatalysis and photodrug design obtained from the spectroscopic-mechanistic studies.
