Two-dimensional (2D) semiconductors based on Transition Metal Dichalcogenides (TMD) are promising candidates as photon absorbing layers in next-generation ultrathin photoconversion devices for solar power harvesting, photodetection, and photocatalysis. In FLASH-2D we will tackle key issues developing original solutions beyond the state-of-the-art by combining the well-matched experimental and theoretical expertise in nanofabrication, nanospectroscopy and nanophotonics of the partner units.