Quantum dots, and an electronic device including the same

Patent metadata

Field	Value
Publication number	US-11512254-B2
Application number	US-202017036122-A
Country	US
Kind code	B2
Filing date	Sep 29, 2020
Priority date	Oct 7, 2019
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

A quantum dot including a core including a first semiconductor nanocrystal including a Group III-V compound, and a shell disposed on the core and including a semiconductor nanocrystal including a Group II-VI compound, wherein the quantum dots do not include cadmium, the shell includes a first layer disposed directly on the core and including a second semiconductor nanocrystal including zinc and selenium, a second layer, the second layer being an outermost layer of the shell and including a third semiconductor nanocrystal including zinc and sulfur, and a third layer disposed between the first layer and the second layer and including a fourth semiconductor nanocrystal including zinc, selenium, and optionally sulfur, and a difference between a peak emission wavelength of a colloidal solution of the quantum dot and a peak emission wavelength of a film prepared from the colloidal solution is less than or equal to about 5 nanometers (nm).

First claim

What is claimed is:

1. A quantum dot comprising
a core comprising a first semiconductor nanocrystal comprising a Group III-V compound, and
a shell disposed on the core, the shell comprising a semiconductor nanocrystal comprising a Group II-VI compound,
wherein the quantum dot does not comprise cadmium,
the shell comprises
a first layer disposed directly on the core, the first layer comprising a second semiconductor nanocrystal comprising zinc and selenium,
a second layer, the second layer being an outermost layer of the shell, the second layer comprising a third semiconductor nanocrystal comprising zinc and sulfur and
a third layer disposed between the first layer and the second layer, the third layer comprising a fourth semiconductor nanocrystal comprising zinc, selenium, and optionally sulfur, and

a difference between a peak emission wavelength of a colloidal solution of the quantum dot and a peak emission wavelength of a film prepared from the colloidal solution is less than or equal to about 5 nanometers.

2. The quantum dot of claim 1 , wherein a difference between a maximum peak emission wavelength of a colloidal solution of the quantum dot and a maximum peak emission wavelength of a film prepared from the colloidal solution is less than or equal to about 4 nanometers.

3. The quantum dot of claim 1 , wherein a diameter of the quantum dot is greater than or equal to about 9 nanometers and a ratio of a mole number of selenium to a mole number of sulfur in the quantum dot is greater than or equal to about 4.5:1.

4. The quantum dot of claim 1 , wherein a sum of a thickness of the first layer of the shell and a thickness of the third layer of the shell is greater than or equal to about 2.5 nanometers.

5. The quantum dot of claim 1 , wherein a diameter of the quantum dot is greater than or equal to about 9.5 nanometers, and a ratio of a mole number of selenium to a mole number of sulfur in the quantum dot is greater than or equal to about 4.6.

6. The quantum dot of claim 1 , wherein a sum of a thickness of the first layer of the shell and a thickness of the third layer of the shell is greater than or equal to about 2.8 nanometers.

7. The quantum dot of claim 1 , wherein the fourth semiconductor nanocrystal further comprises sulfur.

8. The quantum dot of claim 1 , wherein the third semiconductor nanocrystal consists of zinc and sulfur.

9. The quantum dot of claim 8 , wherein a thickness of the second layer is less than about 0.5 nanometers.

10. The quantum dot of claim 1 , wherein a thickness of the second layer is less than about 1 nanometer.

11. The quantum dot of claim 1 , wherein the first semiconductor nanocrystal comprises indium and phosphorus.

12. The quantum dot of claim 11 , wherein the first semiconductor nanocrystal further comprises zinc.

13. The quantum dot of claim 1 , wherein a diameter of the core of the quantum dot is about 2.5 nanometers to about 4 nanometers.

14. The quantum dot of claim 1 , wherein a diameter of the core of the quantum dot is about 3 nanometers to about 3.5 nanometers.

15. The quantum dot of claim 1 , wherein the quantum dot has a peak emission wavelength between 600 nanometers and about 670 nanometers and emit red light.

16. The quantum dot of claim 1 , wherein a full width at half maximum of an emission peak of the quantum dot is less than or equal to about 50 nanometers.

17. The quantum dot of claim 1 , wherein a quantum efficiency of the colloidal solution of the quantum dot is greater than or equal to about 90% and a quantum efficiency of the film prepared from the solution is greater than or equal to about 80%.

18. An electronic device, comprising
a first electrode and a second electrode facing each other; and
a quantum dot light emitting layer disposed between the first electrode and the second electrode, the quantum dot light emitting layer comprising the quantum dot of claim 1 .

19. The electronic device of claim 18 , wherein the electronic device comprises a charge auxiliary layer between the first electrode and the quantum dot light emitting layer, between the second electrode and the quantum dot light emitting layer, or a combination thereof.

20. The electronic device of claim 18 , wherein
the first electrode comprises an anode,
a hole injection layer, a hole transport layer, an electron blocking layer, or a combination thereof is disposed between the first electrode and the quantum dot light emitting layer,
the second electrode comprises a cathode, and
an electron injection layer, an electron transport layer, a hole blocking layer, or a combination thereof is disposed between the second electrode and the quantum dot light emitting layer.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Kim Tae Hyung
• Won Yuho
• Jang Eun Joo
• Chung Heejae
• Cho Oul

Classifications

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C09K11/883 Primary

  with zinc or cadmium · CPC title

• C09K11/02 Primary

  Use of particular materials as binders, particle coatings or suspension media therefor · CPC title

• B82Y20/00

  Nanooptics, e.g. quantum optics or photonic crystals · CPC title

• C09K11/0883

  Arsenides; Nitrides; Phosphides · CPC title