Quantum dots and devices including the same

1. A quantum dot, comprising:

a core comprising a first semiconductor nanocrystal comprising zinc, selenium, and tellurium, and

a semiconductor nanocrystal shell on the core, the semiconductor nanocrystal shell comprising a zinc chalcogenide,

wherein the quantum dot does not comprise cadmium,

the zinc chalcogenide comprises zinc and selenium,

the quantum dot further comprises gallium and a primary amine having 5 or more carbon atoms, and

the quantum dot is configured to emit light having a maximum emission peak in a range of greater than about 450 nanometers and less than or equal to about 480 nanometers by excitation light.

2. The quantum dot of claim 1 , wherein the maximum emission peak has a full width at half maximum of less than about 33 nanometers.

3. The quantum dot of claim 1 , wherein a maximum emission peak wavelength of the quantum dot is greater than or equal to about 453 nanometers.

4. The quantum dot of claim 1 , wherein the first semiconductor nanocrystal or the quantum dot does not comprise a Group III-V compound.

5. The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of tellurium to selenium is greater than or equal to about 0.0053:1.

6. The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of gallium to zinc is greater than or equal to about 0.1:1.

7. The quantum dot of claim 1 , wherein

the zinc chalcogenide further comprises sulfur, and

in the quantum dot, a mole ratio of selenium to zinc is greater than or equal to about 0.46:1 and a mole ratio of sulfur to selenium is less than or equal to about 0.93:1.

8. The quantum dot of claim 1 , wherein the quantum dot has an average decay time for the excitation light of less than or equal to about 50 nanoseconds, as determined by a time-resolved photoluminescence analysis.

9. The quantum dot of claim 1 , wherein the quantum dot has a tellurium relative emission of less than or equal to about 50%, as determined by a time-resolved photoluminescence analysis.

10. The quantum dot of claim 1 , wherein in a gas chromatography mass spectrometry, the quantum dot exhibits a peak of a primary carboxylic acid compound having 10 or more carbon atoms and a peak of the primary amine, and a peak intensity ratio of the peak of the primary amine to the peak of the primary carboxylic acid compound is greater than or equal to about 0.5:1.

11. The quantum dot of claim 10 , wherein a peak intensity ratio of the peak of the primary amine to the peak of the primary carboxylic acid compound is greater than or equal to about 1:1.

12. The quantum dot of claim 1 , wherein the quantum dot has a quantum efficiency of greater than or equal to about 75%.

13. The quantum dot of claim 1 , wherein the quantum dot has a 5% weight loss temperature of less than about 400° C., as determined by a thermogravimetric analysis.

14. The quantum dot of claim 1 , wherein in a thermogravimetric analysis, the quantum dot has an organic material content of less than or equal to about 12 weight percent, as determined by a thermogravimetric analysis.

15. A method of producing the quantum dot of claim 1 , comprising

adding a quantum dot comprising

a core comprising a first semiconductor nanocrystal comprising zinc, selenium, and tellurium, and

a semiconductor nanocrystal shell on the core, the semiconductor nanocrystal shell comprising a zinc chalcogenide to an organic solvent to prepare a mixture; and

adding a gallium treatment agent comprising a gallium compound and a primary amine, and optionally a sulfur treatment agent, to the mixture, and

heating the mixture to a temperature of greater than or equal to about 180° C.

16. The method of claim 15 , wherein the gallium compound comprises alkyl gallium and the gallium treatment agent does not comprise oxygen.

17. The method of claim 15 , comprising adding the sulfur treatment agent to the mixture, wherein the sulfur treatment agent comprises a trialkylsilyl sulfide compound.

18. A quantum dot comprising:

zinc,

selenium,

tellurium, and

sulfur

and not comprising cadmium,

wherein the quantum dot further comprises gallium and a primary amine having 5 or more carbon atoms,

the quantum dot is configured to emit light having a maximum emission peak in a range of greater than or equal to about 453 nanometers and less than or equal to about 480 nanometers by excitation light, and

in the quantum dot, a mole ratio of gallium to zinc is greater than or equal to about 0.1:1 and less than about 1:1.

19. The quantum dot of claim 18 , wherein the quantum dot has a full width at half maximum of less than or equal to about 30 nanometers and a quantum efficiency of greater than or equal to 80%.

20. The quantum dot of claim 18 , wherein the primary amine comprises an alkenyl group having 10 or more carbon atoms.

21. The quantum dot of claim 18 , wherein the quantum dot does not comprise a semiconductor nanocrystal of a Group III-V compound.

22. An electroluminescent device comprising

a first electrode and a second electrode facing each other; and

a quantum dot emission layer between the first electrode and the second electrode, the quantum dot emission layer comprising a plurality of quantum dots,

wherein the plurality of quantum dots comprise the quantum dot of claim 1 .

23. A quantum dot, comprising:

a core comprising a first semiconductor nanocrystal comprising zinc, selenium, and tellurium;

a semiconductor nanocrystal shell on the core, the semiconductor nanocrystal shell comprising zinc and selenium; and

a ligand comprising gallium and a primary amine having 5 or more carbon atoms on a surface of the quantum dot,

wherein the quantum dot does not comprise cadmium,

the quantum dot is configured to emit light having a maximum emission peak in a range of greater than about 450 nanometers and less than or equal to about 480 nanometers by excitation light, and

the maximum emission peak has a full width at half maximum of less than about 33 nanometers.