Light emitting device and display device comprising the same

1 . A light-emitting device comprising:

a first electrode;

a second electrode that overlaps the first electrode;

m emission parts positioned between the first electrode and the second electrode; and

(m−1) charge generating layers disposed between adjacent m emission parts, wherein

each of the charge generating layers includes an n-type charge generating layer and a p-type charge generating layer,

the n-type charge generating layer includes a compound represented by Chemical Formula 1:

wherein in Chemical Formula 1,

R 1 and R 2 each independently includes an aliphatic group, an aromatic group, or a hetero group having 1 to 30 carbon atoms,

A 1 , A 2 , A 3 , and A 4 each independently includes:

hydrogen, an aliphatic group, an aromatic group, or a hetero group; or

an aliphatic group, an aromatic group, or a hetero group, each substituted with at least one of CN, F, or CF3, and

m is a natural number that is greater than or equal to 2, and

wherein when A 4 is an aromatic group, then at least one selected from among A 1 , A 2 , and A 3 is at least one of CN, F, or CF3.

2 . The light-emitting device of claim 1 , wherein the n-type charge generating layer does not contain an inorganic material.

3 . The light-emitting device of claim 1 , wherein a lowest unoccupied molecular orbital (LUMO) energy level of the n-type charge generating layer is in a range of about −2.8 eV to about −3.4 eV.

4 . The light-emitting device of claim 1 , wherein the compound represented by Chemical Formula 1 includes at least one of compounds represented by Chemical Formulas 1-1 to 1-4:

5 . The light-emitting device of claim 1 , wherein the n-type charge generating layer includes a first sub n-type charge generating layer and a second sub n-type charge generating layer.

6 . The light-emitting device of claim 5 , wherein

each of the m emission parts includes a first emission part and a second emission part,

the first sub n-type charge generating layer is positioned adjacent to the first emission part, and

the second sub n-type charge generating layer is positioned adjacent to the second emission part.

7 . The light-emitting device of claim 5 , wherein a lowest unoccupied molecular orbital (LUMO) energy level value of the first sub n-type charge generating layer is greater than a LUMO energy level value of the second sub n-type charge generating layer.

8 . A light-emitting device comprising:

a first electrode;

a second electrode that overlaps the first electrode;

m emission parts positioned between the first electrode and the second electrode; and

(m−1) charge generating layers disposed between adjacent m emission parts, wherein

each of the m emission parts includes a hole transport region, an electron transport region, and an emission layer positioned between the hole transport region and the electron transport region,

the electron transport region includes a compound represented by Chemical Formula 1:

wherein in Chemical Formula 1,

R 1 and R 2 each independently includes an aliphatic group, an aromatic group, or a hetero group having 1 to 30 carbon atoms,

A 1 , A 2 , A 3 , and A 4 each independently includes:

hydrogen, an aliphatic group, an aromatic group, or a hetero group; or

an aliphatic group, an aromatic group, or a hetero group, each substituted with at least one of CN, F, or CF3, and

m is a natural number that is greater than or equal to 2, and

wherein when A 4 is an aromatic group, then at least one selected from among A 1 , A 2 , and A 3 is at least one of CN, F, or CF3.

9 . The light-emitting device of claim 8 , wherein

the electron transport region includes an electron injection layer and an electron transport layer, and

the electron injection layer includes the compound represented by Chemical Formula 1.

10 . The light-emitting device of claim 9 , wherein the electron injection layer does not contain an inorganic material.

11 . The light-emitting device of claim 9 , wherein a lowest unoccupied molecular orbital (LUMO) energy level of the electron injection layer is in a range of about −2.8 eV to about −3.4 eV.

12 . A display device comprising:

a transistor positioned on a substrate; and

a light-emitting device electrically connected to the transistor, wherein

the light-emitting device includes:

a first electrode;

a second electrode that overlaps the first electrode;

m emission parts positioned between the first electrode and the second electrode; and

(m−1) charge generating layers disposed between adjacent m emission parts,

each of the charge generating layers includes an n-type charge generating layer and a p-type charge generating layer,

the n-type charge generating layer includes a compound represented by Chemical Formula 1:

wherein in Chemical Formula 1,

R 1 and R 2 each independently includes an aliphatic group, an aromatic group, or a hetero group having 1 to 30 carbon atoms,

A 1 , A 2 , A 3 , and A 4 each independently includes:

hydrogen, an aliphatic group, an aromatic group, or a hetero group; or

an aliphatic group, an aromatic group, or a hetero group, each substituted with at least one of CN, F, or CF3, and

m is a natural number that is greater than or equal to 2, and

wherein when A 4 is an aromatic group, then at least one selected from among A 1 , A 2 , and A 3 is at least one of CN, F, or CF3.

13 . The display device of claim 12 , wherein the n-type charge generating layer does not contain an inorganic material.

14 . The display device of claim 12 , wherein a lowest unoccupied molecular orbital (LUMO) energy level of the n-type charge generating layer is in a range of about −2.8 eV to about −3.4 eV.

15 . The display device of claim 12 , wherein the n-type charge generating layer includes a first sub n-type charge generating layer and a second sub n-type charge generating layer.

16 . The display device of claim 15 , wherein

each of the m emission parts includes a first emission part and a second emission part,

the first sub n-type charge generating layer is positioned adjacent to the first emission part, and

the second sub n-type charge generating layer is positioned adjacent to the second emission part.

17 . The display device of claim 15 , wherein a lowest unoccupied molecular orbital (LUMO) energy level value of the first sub n-type charge generating layer is greater than a LUMO energy level value of the second sub n-type charge generating layer.

18 . The display device of claim 12 , wherein

the m emission parts include a hole transport region, an electron transport region, and an emission layer positioned between the hole transport region and the electron transport region,

the electron transport region includes an electron injection layer and an electron transport layer, and

the electron injection layer includes the compound represented by Chemical Formula 1.