Electroluminescent device, method of manufacturing the same, and display device including the same
Provided are an electroluminescent device, a method of manufacturing the same, and a display device including the same, the electroluminescent device including 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, wherein the first electron auxiliary layer and the second electron auxiliary layer each include a plurality of zinc oxide nanoparticles, a ratio (t 1 /t 0 ) of a thickness (t 1 ) of the first electron auxiliary layer to a thickness (t 0 ) of the transparent electrode and a ratio (t 2 /t 0 ) of a thickness (t 2 ) of the second electron auxiliary layer to the thickness (t 0 ) of the transparent electrode are each in the range of about 0.1 to about 4.0.
1 . 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 (t 1 /t 0 ) of a thickness (t 1 ) of the first electron auxiliary layer to a thickness (t 0 ) of the transparent electrode and a ratio (t 2 /t 0 ) of a thickness (t 2 ) of the second electron auxiliary layer to the thickness (t 0 ) 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.
2 . The electroluminescent device of claim 1 , wherein
the transparent electrode has a transmittance of greater than or equal to about 90%.
3 . The electroluminescent device of claim 1 , wherein
the transparent electrode is formed in a pattern and is formed in a direction orthogonal to the patterns of the first electrode and the second electrode.
4 . The electroluminescent device of claim 1 , wherein
the zinc oxide nanoparticles further comprise an additional metal selected from Mg, Ca, Zr, W, Li, Ti, Y, Al, or a combination thereof.
5 . The electroluminescent device of claim 1 , wherein
the zinc oxide nanoparticles have a formula Zn 1-x M x O; wherein, M is Mg, Ca, Zr, W, Li, Ti, Y, Al, or a combination thereof, and 0≤x≤0.5.
6 . The electroluminescent device of claim 1 , wherein
an average size of the zinc oxide nanoparticles is about 1 nm to about 10 nm.
7 . The electroluminescent device of claim 1 , wherein
a thickness of each of the first electron transport layer and the second electron transport layer is in a range of about 10 nm to about 90 nm.
8 . The electroluminescent device of claim 1 , wherein
the first light emitting layer and the second light emitting layer comprise the same or different plurality of semiconductor nanoparticles.
9 . The electroluminescent device of claim 1 , wherein
the plurality of semiconductor nanoparticles do not contain cadmium, lead, mercury, or a combination thereof.
10 . The electroluminescent device of claim 1 , wherein
the plurality of semiconductor nanoparticles comprise a first semiconductor nanocrystal containing zinc, selenium, and tellurium, and a second semiconductor nanocrystal containing zinc chalcogenide; where the second semiconductor nanocrystal and is different from the first semiconductor nanocrystal.
11 . The electroluminescent device of claim 1 , wherein
the plurality of semiconductor nanoparticles comprise a first semiconductor nanocrystal containing indium, phosphorus, and, optionally, zinc, and a second semiconductor nanocrystal containing zinc chalcogenide; where the second semiconductor nanocrystal is different from the first semiconductor nanocrystal.
12 . The electroluminescent device of claim 1 , wherein
an average size of the plurality of semiconductor nanoparticles is about 4 nanometers to about 30 nanometers.
13 . The electroluminescent device of claim 1 , wherein
the plurality of semiconductor nanoparticles comprise a core comprising the first semiconductor nanocrystal and a shell disposed on the core and comprising the second semiconductor nanocrystal.
14 . The electroluminescent device of claim 1 , wherein
the first electron transport layer is adjacent to the first light emitting layer and the second electron transport layer is adjacent to the second light emitting layer.
15 . The electroluminescent device of claim 1 , wherein
the electroluminescent device further comprises a first hole auxiliary layer between the first light emitting layer and the first electrode, and
the electroluminescent device further comprise a second hole auxiliary layer between the second light emitting layer and the second electrode.
16 . A method of manufacturing the electroluminescent device, comprising
coating a dispersion containing zinc oxide nanoparticles on a first surface of a transparent electrode and then drying to form a first electron auxiliary layer, coating a composition containing semiconductor nanoparticles on the first electron auxiliary layer and then drying to form a first light emitting layer,
coating a dispersion containing zinc oxide nanoparticles on a second surface of the transparent electrode and then drying to form a second electron auxiliary layer, and coating a composition containing semiconductor nanoparticles on the second electron auxiliary layer and then drying to form a second light emitting layer, where the first surface of the transparent electrode is opposed to the second surface; and
forming a first electrode on the first light emitting layer and forming a second electrode on the second light emitting layer to manufacture of the electroluminescent device of claim 1 .
17 . A display device comprising the electroluminescent device of claim 1 .