Electroluminescent device, method of manufacturing the same, and display device including the same

An electroluminescent device, comprising:

• a first electron auxiliary layer, a first light emitting layer, and a first electrode disposed on a first surface of a transparent electrode;
• and
• a second electron auxiliary layer, a second light emitting layer, and a second electrode disposed on a second surface of the transparent electrode;
• where the second surface is opposed to the first surface;
• wherein each of the first electron auxiliary layer and the second electron auxiliary layer comprise a plurality of zinc oxide nanoparticles,
• a ratio (t1/t0) of a thickness (t1) of the first electron auxiliary layer to a thickness (t0) of the transparent electrode and a ratio (t2/t0) of a thickness (t2) of the second electron auxiliary layer to the thickness (t0) of the transparent electrode are each in the range of about 0.1 to about 4, and
• each of the first light emitting layer and the second light emitting layer comprises a plurality of semiconductor nanoparticles.