Strong quantum-size effects in a layered semiconductor:MoS2nanoclusters

High-quality, size-selected, nano-size (2–15 nm±10%) clusters of ${\mathrm{MoS}}_2$ have been successfully grown inside inverse micellar cages and their optical properties have been studied. These clusters exhibit (1) large blueshifts in the optical-absorption features with decreasing cluster size due to quantum confinement, affording great tailorability in the absorption thresholds and (2) a demonstration of the crossover from bandlike (solid) to moleculelike spectra as the size of the clusters becomes smaller than that of the exciton in the bulk.