Photoluminescence of Eu2+ doped ZnS nanocrystals

Eu2+ doped ZnS nanocrystals exhibit new luminescence properties because of the enlarged energy gap of nanocrystalline ZnS host due to quantum confinem ent effects. Photoluminescence emission at about 520 nm from Eu2+ doped ZnS nanocrystals at room temperature is investigated by using photoluminescenc e emission and excitation spectroscopy. Such green emission with long lifet ime (ms) is proposed to be a result of excitation, ionization, carriers rec apture and recombination via Eu2+ centers in nanocrystalline ZnS host.