Light-emitting devices and displays with improved performance

1. A light-emitting device comprising:

a first electrode comprising an anode opposite a second electrode comprising a cathode;

a hole injection layer adjacent to the first electrode; and

an emissive layer of inorganic semiconductor nanocrystals disposed between the hole injection layer and the second electrode, the inorganic semiconductor nanocrystals comprising a plurality of semiconductor nanocrystals capable of emitting light upon excitation,

wherein the device has an external quantum efficiency of at least about 2.2 percent.

2. The light-emitting device in accordance with claim 1 , wherein at least a portion of the semiconductor nanocrystals comprise a core including a first semiconductor material comprising a ternary semiconductor material and a shell overcoating the core, the shell comprising a second semiconductor material.

3. The light-emitting device in accordance with claim 2 , wherein the first semiconductor nanocrystal comprises a ternary semiconductor nanocrystal comprising a Group II-VI compound, a Group III-V compound, or a combination thereof.

4. The light-emitting device in accordance with claim 1 , further comprising:

a hole transporting layer disposed between the hole injection layer and the emissive layer of inorganic semiconductor nanocrystals.

5. The light-emitting device in accordance with claim 1 , further comprising:

an electron transporting layer disposed between the second electrode and the emissive layer of inorganic semiconductor nanocrystals.

6. The light-emitting device in accordance with claim 1 , wherein the device emits light having a CIE color coordinate of x greater than 0.63.

7. The light-emitting device in accordance with claim 1 wherein the emissive layer comprises semiconductor nanocrystals capable of emitting green light upon excitation or semiconductor nanocrystals capable of emitting red light upon excitation.

8. A light-emitting device comprising:

a first electrode comprising an anode opposite to a second electrode comprising a cathode;

a hole injection layer adjacent to the first electrode; and

an emissive layer of inorganic semiconductor nanocrystals disposed between the hole injection layer and the second electrode, the inorganic semiconductor nanocrystals comprising a plurality of semiconductor nanocrystals capable of emitting light upon excitation,

wherein the device is capable of emitting light with a brightness of at least 100 nits when driven at a voltage less than or equal to 4 volts.

9. The light-emitting device in accordance with claim 8 , wherein at least a portion of the semiconductor nanocrystals comprise a core including a first semiconductor material comprising a ternary semiconductor material and a shell overcoating the core, the shell comprising a second semiconductor material.

10. The light-emitting device in accordance with claim 9 , wherein the first semiconductor nanocrystal comprises a ternary semiconductor nanocrystal comprising a Group II-VI compound, a Group III-V compound, or a combination thereof.

11. The light-emitting device in accordance with claim 8 , further comprising:

a hole transporting layer disposed between the hole injection layer and the emissive layer of inorganic semiconductor nanocrystals.

12. The light-emitting device in accordance with claim 8 , further comprising:

an electron transporting layer disposed between the second electrode and the emissive layer of inorganic semiconductor nanocrystals.

13. The light-emitting device in accordance with claim 8 , wherein the device emits light having a CIE color coordinate of x greater than 0.63.

14. The light-emitting device in accordance with claim 8 , wherein the device has an external quantum efficiency of at least about 2.2 percent.

15. A light-emitting device comprising:

a first electrode comprising an anode opposite a second electrode comprising a cathode;

a hole injection layer adjacent the first electrode; and

an emissive layer of inorganic semiconductor nanocrystals disposed between the hole injection layer and the second electrode, the inorganic semiconductor nanocrystals comprising a plurality of semiconductor nanocrystals capable of emitting light upon excitation,

wherein at least a portion of the semiconductor nanocrystals comprise a core including a first semiconductor material comprising a ternary semiconductor material and a shell overcoating the core, the shell comprising a second semiconductor material, and

wherein the ternary semiconductor material comprises a Group II-VI compound, a Group III-V compound, or a combination thereof.

16. The light-emitting device in accordance with claim 15 , further comprising:

a hole transporting layer disposed between the hole injection layer and the emissive layer of inorganic semiconductor nanocrystals.

17. The light-emitting device in accordance with claim 15 , further comprising;

an electron transporting layer disposed between the second electrode and the emissive layer of inorganic semiconductor nanocrystals.

18. A light-emitting device comprising:

a first electrode comprising an anode opposite a second electrode comprising a cathode;

a hole injection layer adjacent to the first electrode; and

an emissive layer of inorganic semiconductor nanocrystals disposed between the hole injection layer and the second electrode, the inorganic semiconductor nanocrystals comprising a plurality of semiconductor nanocrystals capable of emitting light upon excitation,

wherein the device emits light having a CIE color coordinate of x greater than 0.63.

19. The light-emitting device in accordance with claim 18 , further comprising:

a hole transporting layer disposed between the hole injection layer and the emissive layer of inorganic semiconductor nanocrystals.

20. The light-emitting device in accordance with claim 18 , further comprising:

an electron transporting layer disposed between the second electrode and the emissive layer of inorganic semiconductor nanocrystals.