Photoluminescence of Eu²⁺ Doped ZnS Nanocrystals

Eu²⁺ doped ZnS nanocrystals exhibit new luminescence properties because of the enlarged energy gap of nanocrys-talline ZnS host due to quantum confinement effects. Photoluminescence emission at about 520nm from Eu²⁺ doped ZnS nanocrystals at room temperature is investigated by using photoluminescence emission and excitation spectroscopy Such green emission with long lifetime (ms) is proposed to be a result of excitation, ionization, carriers recapture and recombination via Eu²⁺ centers in nanocrystalline ZnS host.