Quantum dots, production method thereof, and composite and electronic device including the same
A quantum dot including a semiconductor nanocrystal core and a semiconductor nanocrystal shell disposed on the core and does not include cadmium, wherein the core includes a Group III-V compound, the quantum dot has a maximum photoluminescence peak in a green light wavelength region, a full width at half maximum (FWHM) of the maximum photoluminescence peak is less than about 50 nanometers (nm), and a difference between a wavelength of the maximum photoluminescence peak and a first absorption peak wavelength of the quantum dot is less than or equal to about 25 nanometers, and a production method thereof.
1. A quantum dot, comprising
a semiconductor nanocrystal core and a semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core,
wherein the quantum dot does not comprise cadmium,
the core comprises a Group III-V compound comprising a group III metal and a group V element,
the quantum dot has a maximum photoluminescence peak in a green light wavelength region,
a full width at half maximum of the maximum photoluminescence peak is less than about 50 nanometers, and
a difference between a wavelength of the maximum photoluminescence peak and a first absorption peak wavelength of the quantum dot is less than 22 nanometers.
2. The quantum dot of claim 1 , wherein the green light wavelength region is greater than or equal to about 500 nanometers and less than or equal to about 560 nanometers.
3. The quantum dot of claim 1 , wherein the full width at half maximum of the maximum photoluminescence peak is less than or equal to about 35 nanometers.
4. The quantum dot of claim 1 , wherein the quantum dot comprises indium and zinc.
5. The quantum dot of claim 1 , wherein the quantum dot has a size of greater than or equal to about 5 nanometers and less than or equal to about 8 nanometers.
6. The quantum dot of claim 1 , wherein the quantum dot has quantum efficiency of greater than or equal to about 80%.
7. A quantum dot, comprising
a semiconductor nanocrystal core and a semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core,
wherein the quantum dot does not comprise cadmium,
the core comprises a Group III-V compound comprising a group III metal and a group V element,
the quantum dot has a maximum photoluminescence peak in a green light wavelength region,
a full width at half maximum of the maximum photoluminescence peak is less than about 50 nanometers, and
a difference between a wavelength of the maximum photoluminescence peak and a first absorption peak wavelength of the quantum dot is less than or equal to 23 nanometers, and wherein the quantum dot further comprises an additive comprising Sn, Bi, or a combination thereof.
8. The quantum dot of claim 1 , wherein the shell comprises
a first semiconductor nanocrystal shell comprising zinc and selenium and
a second semiconductor nanocrystal shell disposed on the first semiconductor nanocrystal shell, the second semiconductor nanocrystal shell comprising zinc and sulfur.
9. The quantum dot of claim 8 , wherein the first semiconductor nanocrystal shell is disposed directly on a surface of the semiconductor nanocrystal core, and
the first semiconductor nanocrystal shell does not comprise sulfur.
10. The quantum dot of claim 8 , wherein the first semiconductor nanocrystal shell has a thickness of less than or equal to about 6 monolayers.
11. The quantum dot of claim 8 , wherein second semiconductor nanocrystal shell is an outermost layer of the quantum dot.
12. The quantum dot of claim 8 , wherein the second semiconductor nanocrystal shell is directly disposed on the first semiconductor nanocrystal shell and the second semiconductor nanocrystal shell comprises ZnSeS, ZnS, or a combination thereof.
13. The quantum dot of claim 1 , wherein in a photoluminescent spectrum of the quantum dot, a ratio of an intensity at a tail initiation wavelength with respect to an intensity at a maximum photoluminescent peak wavelength is less than or equal to about 0.11:1.
14. A quantum dot, comprising
a semiconductor nanocrystal core and a semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core,
wherein the quantum dot does not comprise cadmium,
the core comprises a Group III-V compound comprising a group III metal and a group V element,
the quantum dot has a maximum photoluminescence peak in a green light wavelength region,
a full width at half maximum of the maximum photoluminescence peak is less than about 50 nanometers, and
a difference between a wavelength of the maximum photoluminescence peak and a first absorption peak wavelength of the quantum dot is less than or equal to 23 nanometers,
wherein the shell comprises
a first semiconductor nanocrystal shell comprising zinc and selenium and
a second semiconductor nanocrystal shell disposed on the first semiconductor nanocrystal shell, the second semiconductor nanocrystal shell comprising zinc and sulfur, and
wherein the second semiconductor nanocrystal shell has a thickness of less than 0.7 nanometers.
15. The quantum dot of claim 7 , wherein a molar amount of the additive is less than about 0.1 moles with respect to 1 mole of the Group III metal.
16. The quantum dot of claim 1 , wherein
the core comprises indium, phosphorus, and optionally zinc and
the shell comprises zinc, sulfur, and selenium.
17. The quantum dot of claim 16 , wherein in the quantum dot, a mole ratio of sulfur and selenium relative to indium ((S+Se)/In) is greater than or equal to about 20:1 and less than or equal to about 36:1.
18. The quantum dot of claim 16 , wherein in the quantum dot, a mole ratio of phosphorus relative to indium is greater than or equal to about 0.6:1 and less than or equal to about 0.9:1.
19. The quantum dot of claim 16 , wherein in the quantum dot, a mole ratio of zinc relative to indium is greater than or equal to about 25:1 and less than or equal to about 40:1.
20. The quantum dot of claim 1 , wherein the quantum dot has an average size of about greater than or equal to 5.5 nanometers.
21. The quantum dot of claim 1 , wherein the difference between the wavelength of the maximum photoluminescence peak and the first absorption peak wavelength of the quantum dot is greater than or equal to about 5 nanometers and less than 20 nanometers.
22. A method of producing the quantum dot of claim 1 , comprising:
preparing a semiconductor nanocrystal core comprising a Group III-V compound;
preparing a first solution comprising a shell metal precursor and an organic ligand;
adding the semiconductor nanocrystal core not comprising the semiconductor nanocrystal shell to the first solution at a first temperature; and
heating the first solution comprising the semiconductor nanocrystal core to a second temperature and adding a shell non-metal precursor to the first solution to form the semiconductor nanocrystal shell on a surface of the semiconductor nanocrystal core and produce the quantum dot,
wherein the first temperature is less than or equal to about 140° C. and the second temperature is greater than or equal to about 290° C. and less than or equal to about 350° C.
23. The method of claim 22 , wherein the semiconductor nanocrystal core further comprises an additive comprising Sn, Sb, Bi, or a combination thereof.
24. The method of claim 22 , wherein the first temperature is less than or equal to about 120° C. and the second temperature is greater than or equal to about 300° C. and less than or equal to about 330° C.
25. The method of claim 22 , wherein forming of the semiconductor nanocrystal shell comprises adding the shell non-metal precursor and optionally a shell metal precursor to the first solution at least twice.
26. The method of claim 22 , wherein the method further comprises adding ammonium fluoride, a Group IV element, or a combination thereof to the first solution during formation of the semiconductor nanocrystal shell.
27. The method of claim 22 , wherein during preparation of the semiconductor nanocrystal core, during formation of the semiconductor nanocrystal shell, or both, a group V element precursor is added at least two times.
28. The quantum dot of claim 1 , wherein the difference between the wavelength of the maximum photoluminescence peak and the first absorption peak wavelength of the quantum dot is greater than or equal to about 5 nanometers and less than or equal to 21 nanometers.