Electroluminescent compound and electroluminescent device including the same

1. An electroluminescent device, comprising:

a first electrode;

a second electrode facing the first electrode;

at least one organic material layer between the first and second electrodes; and

a light-efficiency enhancing layer on a side of one of the first electrode and the second electrode,

wherein the light-efficiency enhancing layer is positioned to be opposite to the organic material layer,

wherein the light-efficiency enhancing layer includes an electroluminescent compound of Formula 1;

wherein one or more of the at least one organic material layer includes the electroluminescent compound of Formula 1, and

wherein the electroluminescent compound of Formula 1 is:

wherein each of X 1 to X 4 is independently N or CR′,

wherein each of R and R′ is independently selected from the group consisting of hydrogen, deuterium, cyano group, hydroxyl group, halogen, a substituted or non-substituted C1 to C10 alkyl group, a substituted or non-substituted C6 to C20 aryl group and a substituted or non-substituted C3 to C30 heteroaryl group,

wherein L 1 is selected from a single bond, a substituted or non-substituted C6 to C20 arylene group and a substituted or non-substituted C3 to C30 heteroarylene group, and

wherein Ar 1 is a substituted or non-substituted C6 to C20 aryl group, and Ar 2 is a substituted or non-substituted C3 to C30 heteroaryl group.

2. The electroluminescent device according to claim 1 , wherein L 1 is selected from Formula 3a and 3b:

wherein each of X 5 to X 7 is independently N or CR 1 ,

wherein each of Y 1 and Y 2 is independently selected from a single bond, O, S, Se, Si(R 2 )(R 4 ), and C(R 3 )(R 5 ), and

wherein each of R 1 , R 2 , R 3 , R 4 and R 5 is independently selected from the group consisting of hydrogen, deuterium, cyano group, hydroxyl group, halogen, a substituted or non-substituted C1 to C10 alkyl group, a substituted or non-substituted C6 to C20 aryl group and substituted or a non-substituted C3 to C30 heteroaryl group.

3. The electroluminescent device according to claim 1 , wherein when substituted, each substituent of L 1 , Ar 1 and Ar 2 is independently selected from the group consisting of deuterium, cyano group, halogen, amino group, hydroxyl group, nitro group, a substituted or non-substituted C1 to C10 alkyl group, a substituted or non-substituted C1 to C10 halogenated alkyl group, a substituted or non-substituted C6 to C20 aryl group, a substituted or non-substituted C3 to C30 heteroaryl group, a substituted or non-substituted C1 to C10 alkoxy group, a substituted or non-substituted C1 to C10 alkylsilyl group and a substituted or non-substituted C6 to C20 arylsilyl group.

4. The electroluminescent device according to claim 1 , wherein the electroluminescent compound is selected from Formula 5:

5. The electroluminescent device according to claim 1 , wherein the at least one organic material layer includes at least one of an electron injection layer, an electron transporting layer, a hole injection layer, a hole transporting layer, an electron blocking layer, a hole blocking layer and an emitting material layer.

6. The electroluminescent device according to claim 5 , wherein the hole transporting layer includes the electroluminescent compound.

7. The electroluminescent device according claim 1 , wherein the light-efficiency enhancing layer is formed on at least one of a lower surface of the first electrode and an upper surface of the second electrode.

8. The electroluminescent device according to claim 1 , wherein L 1 is selected from Formula 3a and 3b:

wherein each of X 5 to X 7 is independently N or CR 1 ,

wherein each of Y 1 and Y 2 is independently selected from a single bond, O, S, Se, Si(R 2 )(R 4 ), and C(R 3 )(R 5 ), and

wherein each of R 1 , R 2 , R 3 , R 4 and R 5 is independently selected from the group consisting of hydrogen, deuterium, cyano group, hydroxyl group, halogen, a substituted or non-substituted C1 to C10 alkyl group, a substituted or non-substituted C6 to C20 aryl group and a substituted or non-substituted C3 to C30 heteroaryl group.

9. The electroluminescent device of claim 1 , wherein R and R′ are hydrogen.

10. An electroluminescent compound selected from Formula 5:

11. An electroluminescent compound selected from Formula 5:

12. An electroluminescent device, comprising:

a first electrode;

a second electrode facing the first electrode;

at least one organic material layer between the first and second electrodes and including an electron injection layer, an electron transporting layer, a hole injection layer, a hole transporting layer, an electron blocking layer, a hole blocking layer and an emitting material layer, and

a light-efficiency enhancing layer on a side of one of the first electrode and the second electrode, the light-efficiency enhancing layer is positioned to be opposite to the organic material layer,

wherein one or more of the hole transporting layer and light-efficiency enhancing layer includes an electroluminescent compound of Formula 2:

wherein each of X 1 to X 4 is independently N or CR′,

wherein each of R and R′ is independently selected from the group consisting of hydrogen, deuterium, cyano group, hydroxyl group, halogen, a substituted or non-substituted C1 to C10 alkyl group, a substituted or non-substituted C6 to C20 aryl group and a substituted or non-substituted C3 to C30 heteroaryl group,

wherein L 2 is selected from a single bond, a substituted or non-substituted C6 to C20 arylene group and a substituted or non-substituted C3 to C30 heteroarylene group,

wherein Ar is selected from the group consisting of a substituted or non-substituted C6 to C20 arylene group and a substituted or non-substituted C3 to C30 heteroarylene group, and

wherein each of Ar 1 and Ar 2 is independently selected from the group consisting of a substituted or non-substituted C6 to C20 aryl group and a substituted or non-substituted C3 to C30 heteroaryl group.

13. The electroluminescent device according to claim 12 , wherein the electroluminescent compound is selected from Formula 5: