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 a t 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 yie lding an external photoluminescent quantum efficiency 18% and a lumine scent decay at least 5 orders of magnitude faster than the correspondi ng Mn2+ transition in the bulk crystals. The quantum efficiency increa ses with decreasing size of the particles. These results suggest that doped nanocrystals are indeed a new class of materials heretofore unkn own.