Green emission from ZnS nanocrystals (NCs) doped with Tb compounds has been investigated employing a double insulating thin-film electroluminescent device (TFELD) structure which has been used for conventional ac-driven TFELDs. The EL emission mechanism is discussed, centered on the generation of electric-field-induced high-energy electrons in NCs. The influence of Tb concentrations and co-doping of Tb compounds on the device performance is presented. Finally, green EL emission with a maximum luminance of 30 cd/m(2) at 90 V0-p employing ZnS:Tb,O,F NCs as the active layer is demonstrated. (c) 2004 Elsevier B.V. All rights reserved.