In project W03, we aim to reveal the mechanisms of nonlinear exciton-plasmon coupling in the monolithic system copper monosulfide (CuS), which combines in one nano unit excitonic and plasmonic transitions in spectral vicinity. Our goal is to enhance nonlinear optical phenomena to a maximum by systematically modifying shape, size, and geometry of sheet-like CuS nanocrystals. Steady-state and time-resolved spectroscopy will be employed to study the photoluminescence for nonlinear excitation. A systematic experimental study will be flanked by theoretical efforts, unravelling the fundamental mechanisms and efficient strategies for near-infrared light harvesting based on surface plasmon-induced phenomena.