An electroluminescent device including an anode; a cathode; a light emitting layer disposed between the anode and the cathode; and an electron transport layer disposed between the light emitting layer and the cathode, wherein the light emitting layer includes a plurality of semiconductor nanoparticles, the electron transport layer includes zinc oxide nanoparticles including a Group IIA metal and an acid salt of an alkali metal that has an oxycarbonyl moiety, and the zinc oxide nanoparticles have an average size of less than or equal to about 20 nanometers (nm).