Light emitting device and display apparatus including the same

A light emitting device comprising:

• a first electrode;
• a plurality of first light emitting layers on the first electrode and configured to emit light of a first wavelength;
• a second light emitting layer on the first electrode and configured to emit light of a second wavelength different from the first wavelength;
• an electron transport region comprising an electron transport layer on the first light emitting layer and the second light emitting layer, and an electron injection layer on the electron transport layer;
• and
• a second electrode on the electron transport region,
• wherein a plurality of first light emitting layers comprise a first first-light emitting layer, a second first-light emitting layer, and a third first-light emitting layer, and the electron injection layer comprises magnesium (Mg) and ytterbium (Yb),
• wherein a mass ratio of the magnesium (Mg) and the ytterbium (Yb) is about 5:5 to about 8:2, and
• wherein a thickness of the electron injection layer is about 1 nm to about 2 nm.

A display apparatus comprising:

• a substrate on which a first pixel region configured to emit light of a first wavelength, a second pixel region configured to emit light of a second wavelength different from the first wavelength, and a third pixel region configured to emit light of a third wavelength different from the first wavelength and the second wavelength are defined;
• and
• a plurality of light emitting devices that overlap the first pixel region, the second pixel region, and the third pixel region on the substrate,
• wherein each of the plurality of light emitting devices comprises:
• a first electrode;
• a hole transport region on the first electrode;
• a first light emitting layer on the hole transport region and configured to emit the light of the first wavelength;
• a second light emitting layer on the hole transport region and configured to emit the light of the second wavelength;
• an electron transport region comprising an electron transport layer on the first light emitting layer and the second light emitting layer, and an electron injection layer on the electron transport layer;
• and
• a second electrode on the electron transport region,
• wherein the electron injection layer comprises magnesium (Mg) and ytterbium (Yb),
• wherein a mass ratio of the magnesium (Mg) and the ytterbium (Yb) is about 5:5 to about 8:2, and
• wherein a thickness of the electron injection layer is about 1 nm to about 2 nm.