Quantum well nanocrystals with quaternary alloy structure for improved light absorption

Patent metadata

Field	Value
Publication number	US-2021284907-A1
Application number	US-202117199613-A
Country	US
Kind code	A1
Filing date	Mar 12, 2021
Priority date	Mar 13, 2020
Publication date	Sep 16, 2021
Grant date	—

Abstract

A quantum dot, and a quantum dot composite and a device including the same are disclosed, wherein the quantum dot includes a template including a first semiconductor nanocrystal, a quantum well (e.g., quantum well layer) disposed on the template and a shell disposed on the quantum well, the shell including a second semiconductor nanocrystal, and wherein the quantum dot does not include cadmium, wherein the first semiconductor nanocrystal includes a first zinc chalcogenide, wherein the second semiconductor nanocrystal includes a second zinc chalcogenide, and the quantum well layer includes an alloy semiconductor nanocrystal including indium (In), phosphorus (P), zinc (Zn), and a chalcogen element wherein a bandgap energy of the alloy semiconductor nanocrystal is less than a bandgap energy of the first semiconductor nanocrystal and less than a bandgap energy of the second semiconductor nanocrystal.

First claim

What is claimed is:

1 . A quantum dot comprising
a template comprising a first semiconductor nanocrystal, a quantum well layer disposed on the template, and a shell disposed on the quantum well layer, the shell comprising a second semiconductor nanocrystal, wherein the quantum dot does not comprise cadmium, wherein the first semiconductor nanocrystal comprises a first zinc chalcogenide, wherein the second semiconductor nanocrystal comprises a second zinc chalcogenide, wherein the quantum well layer comprises an alloy semiconductor nanocrystal comprising indium, phosphorus, zinc, and a chalcogen element, and wherein a bandgap energy of the alloy semiconductor nanocrystal is less than a bandgap energy of the first semiconductor nanocrystal and less than a bandgap energy of the second semiconductor nanocrystal.

2 . The quantum dot of claim 1 , wherein
the first zinc chalcogenide comprises ZnSe, ZnTeSe, ZnSeS, ZnS, or a combination thereof, and the second zinc chalcogenide independently comprises ZnSe, ZnTeSe, ZnSeS, ZnS, or a combination thereof.

3 . The quantum dot of claim 1 , wherein the first semiconductor nanocrystal and the second semiconductor nanocrystal have different compositions from one another.

4 . The quantum dot of claim 1 , wherein
the first semiconductor nanocrystal comprises ZnSe, ZnTeSe, ZnSeS, ZnS, or a combination thereof, and the second semiconductor nanocrystal comprises ZnSe, ZnSeS, ZnS, or a combination thereof.

5 . The quantum dot of claim 1 , wherein the chalcogen element comprises sulfur.

6 . The quantum dot of claim 1 , wherein a difference between a lattice constant of the alloy semiconductor nanocrystal and the first semiconductor nanocrystal is less than or equal to about 3%, and
wherein a difference between a lattice constant of the alloy semiconductor nanocrystal and the second semiconductor nanocrystal is less than or equal to about 3%.

7 . The quantum dot of claim 1 , wherein the quantum dot has a total molar amount of indium and phosphorus of less than or equal to about 20%, based on a total number of moles of elements in the quantum dot.

8 . The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of phosphorus with respect to indium is greater than or equal to about 0.5:1 and less than or equal to about 0.9:1.

9 . The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of zinc with respect to indium is greater than or equal to about 15:1 and less than or equal to about 55:1.

10 . The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of a sum of sulfur and selenium with respect to zinc is greater than or equal to about 0.5:1 and less than or equal to about 1:1.

11 . The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of sulfur with respect to selenium is greater than or equal to about 0.3:1 and less than or equal to about 0.9:1.

12 . The quantum dot of claim 1 , wherein the shell comprises
a first layer comprising a third zinc chalcogenide, and a second layer comprising a fourth zinc chalcogenide having a different composition from the third zinc chalcogenide.

13 . The quantum dot of claim 12 , wherein
the first layer comprises ZnSe, ZnSeS, or a combination thereof, and the second layer comprises ZnS.

14 . The quantum dot of claim 12 , wherein
the first layer is directly on the quantum well layer, and the second layer is an outermost layer of the shell.

15 . The quantum dot of claim 1 , wherein a thickness of the quantum well layer is greater than or equal to about 0.1 nanometers and less than or equal to about 0.35 nanometers.

16 . The quantum dot of claim 1 , wherein a size of the quantum dot is greater than or equal to about 3 nanometers and less than or equal to about 7 nanometers.

17 . The quantum dot of claim 1 , wherein the quantum dot comprises an organic ligand on a surface thereof, and the organic ligand comprises RCOOH, RCOOCOR, RNH 2 , R 2 NH, R 3 N, RSH, R 3 PO, R 3 P, ROH, RCOOR′, RPO(OH) 2 , R 2 POOH, or a combination thereof, wherein R and R′ are independently a substituted or unsubstituted C1 to C30 aliphatic hydrocarbon, a substituted or unsubstituted C6 to C30 aromatic hydrocarbon, or a combination thereof.

18 . The quantum dot of claim 1 , wherein
the quantum dot emits green light, and an ultraviolet-visible absorption spectrum curve of the quantum dot does not have an inflection point within a wavelength range of about 450 nanometers to about 620 nanometers.

19 . The quantum dot of claim 1 , wherein the quantum dot exhibits a maximum luminescent peak wavelength in a range of about 500 nanometers to about 540 nanometers.

20 . The quantum dot of claim 1 , wherein a quantum efficiency of the quantum dot is greater than or equal to about 40%.

21 . A quantum dot polymer composite comprising
a polymer matrix; and a plurality of quantum dots of claim 1 dispersed in the polymer matrix.

22 . The quantum dot-polymer composite of claim 21 , wherein the polymer matrix comprises a linear polymer, a crosslinked polymer, or a combination thereof.

23 . The quantum dot-polymer composite of claim 21 , wherein the polymer matrix further comprises a polymerization product of a monomer combination comprising a thiol compound and an ene compound having a carbon-carbon unsaturated bond, a metal oxide particulate, or a combination thereof.

24 . The quantum dot-polymer composite of claim 21 , wherein the quantum dot polymer composite is in a form of a patterned film.

25 . The quantum dot-polymer composite of claim 21 , wherein the quantum dot polymer composite exhibits an absorption of greater than or equal to about 90% for blue light or a blue light conversion efficiency of greater than or equal to about 15% after the quantum dot polymer composite is thermally treated at a temperature of about 180° C. for 30 minutes.

26 . A display device, comprising
a light emitting element, wherein the light emitting element comprises the quantum dot-polymer composite of claim 21 .

27 . The display device of claim 26 , further comprising a light source, wherein the light source is configured to provide the light emitting element with incident light, and
wherein the incident light comprises a light having a peak wavelength of about 440 nanometers to about 460 nanometers.

28 . The display device of claim 26 , wherein the light emitting element comprises a sheet of the quantum dot polymer composite.

29 . The display device of claim 26 , wherein the light emitting element comprises a stacked structure comprising
a substrate, and a light emitting layer disposed on the substrate, wherein the light emitting layer comprises a pattern comprising the quantum dot-polymer composite, and wherein the pattern comprises a repeating section emitting light of a predetermined wavelength.

30 . The display device of claim 29 , wherein the pattern comprises a first repeating section emitting first light and a second repeating section emitting a second light having a different emission peak wavelength from the first light.

Assignees

• Samsung Display Co Ltd

Inventors

• Ahn Jooyeon
• Yang Hyeyeon
• Kim Tae Gon
• Lee Jongmin
• Jun Shin Ae

Classifications

• B82Y20/00

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

• C09K11/883

  with zinc or cadmium · CPC title

• G02F1/1336

  Illuminating devices · CPC title

• B82Y30/00

  Nanotechnology for materials or surface science, e.g. nanocomposites · CPC title

• C09K11/025 Primary

  non-luminescent particle coatings or suspension media · CPC title