OPTICAL-PROPERTIES OF MANGANESE-DOPED NANOCRYSTALS OF ZNS

We report for the first time that doped nanocrystals of semiconductor can yield both high luminescent efficiencies and lifetime shortening at the same time. Nanocrystals of Mn-doped ZnS with sizes varying from 3.5 to 7.5 nm were prepared by a room temperature chemical process yielding an external photoluminescent quantum efficiency 18% and a luminescent decay at least 5 orders of magnitude faster than the corresponding Mn2+ transition in the bulk crystals. The quantum efficiency increases with decreasing size of the particles. These results suggest that doped nanocrystals are indeed a new class of materials heretofore unknown.