Cadmium free quantum dots

Patent metadata

Field	Value
Publication number	US-2022017818-A1
Application number	US-202117490552-A
Country	US
Kind code	A1
Filing date	Sep 30, 2021
Priority date	Jan 11, 2018
Publication date	Jan 20, 2022
Grant date	—

Abstract

A cadmium free quantum dot not including cadmium and including: a semiconductor nanocrystal core comprising indium and phosphorous, a first semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core and comprising zinc and selenium, and a second semiconductor nanocrystal shell disposed on the first semiconductor nanocrystal shell and comprising zinc and sulfur, a composition and composite including the same, and an electronic device.

First claim

What is claimed is:

1 . A cadmium free quantum dot comprising:
a semiconductor nanocrystal core comprising indium and phosphorous, a semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core, the semiconductor nanocrystal shell comprising zinc, selenium, and sulfur, wherein the cadmium free quantum dot does not comprise cadmium, and wherein the cadmium free quantum dot has a quantum yield of greater than about 80%, and wherein when the cadmium free quantum dot has a photoluminescent peak wavelength in a range from about 600 nanometers to about 650 nanometers, a molar ratio of indium to a sum of sulfur and selenium is greater than or equal to about 0.06:1 and less than or equal to about 0.3:1, or wherein when the cadmium free quantum dot has a photoluminescent peak wavelength in a range from about 500 nanometers to about 550 nanometers, a molar ratio of indium to a sum of sulfur and selenium is greater than or equal to about 0.027:1 and less than or equal to about 0.1:1.

2 . The cadmium free quantum dot of claim 1 , wherein in an ultraviolet-visible absorption spectrum of the cadmium free quantum dot, a ratio of an intensity of 450 nanometers to that of the first absorption peak wavelength is greater than or equal to about 1.1:1.

3 . The cadmium free quantum dot of claim 1 , wherein the semiconductor nanocrystal core further comprises zinc.

4 . The cadmium free quantum dot of claim 1 , wherein in the cadmium free quantum dot, a mole ratio of sulfur with respect to indium is from about 1:1 to about 15:1.

5 . The cadmium free quantum dot of claim 1 , wherein in the cadmium free quantum dot, a mole ratio of sulfur with respect to indium is from about 2:1 to about 9:1.

6 . The cadmium free quantum dot of claim 1 , wherein in the cadmium free quantum dot, a mole ratio of selenium with respect to indium is from about 1:1 to about 15:1.

7 . The cadmium free quantum dot of claim 1 , wherein in the cadmium free quantum dot, a mole ratio of selenium with respect to indium is from about 5:1 to about 40:1.

8 . The cadmium free quantum dot of claim 1 , wherein the cadmium free quantum dot emits green light and a blue light absorption per one gram of the cadmium free quantum dot is greater than or equal to about 2.

9 . The cadmium free quantum dot of claim 1 , wherein the cadmium free quantum dot has a photoluminescent peak wavelength in a range from about 600 nanometers to about 650 nanometers and a molar ratio of indium to a sum of sulfur and selenium is greater than or equal to about 0.064:1 and less than or equal to about 0.25:1.

10 . The cadmium free quantum dot of claim 1 , wherein the cadmium free quantum dot has a photoluminescent peak wavelength in a range from about 500 nanometers to about 550 nanometers and a molar ratio of indium to a sum of sulfur and selenium is greater than or equal to about 0.030:1 and less than or equal to about 0.065:1.

11 . The cadmium free quantum dot of claim 1 , wherein in an ultraviolet-visible absorption spectrum of the cadmium free quantum dot, a ratio of an intensity of 450 nanometers to that of the first absorption peak wavelength is greater than or equal to about 1.5:1.

12 . The cadmium free quantum dot of claim 1 , wherein a blue light absorption per one gram of the cadmium free quantum dot is from about 1.1 to about 5.07.

13 . The cadmium free quantum dot of claim 1 , wherein the cadmium free quantum dot has a quantum yield of greater than about 85%.

14 . The cadmium free quantum dot of claim 1 , wherein the first absorption peak wavelength of the cadmium free quantum dot is present within a range of greater than about 450 nanometers and less than a photoluminescent peak wavelength of the cadmium free quantum dot.

15 . The cadmium free quantum dot of claim 1 , wherein a full width at half maximum of the cadmium free quantum dot is less than or equal to about 44 nanometers.

16 . A composition comprising:
the cadmium free quantum dot of claim 1 ; a polymerizable monomer; and an initiator.

17 . The composition of claim 16 , wherein the composition further comprises a thiol compound, a metal oxide particle, or a combination thereof.

18 . A quantum dot-polymer composite comprising:
a polymer matrix; and the cadmium free quantum dots of claim 1 dispersed in the polymer matrix.

19 . The quantum dot-polymer composite of claim 18 , wherein the quantum dot polymer composite has a blue light absorption rate of greater than or equal to about 82% with respect to light having a wavelength of 450 nanometers, a photoconversion efficiency of greater than or equal to about 20%, or a combination thereof.

20 . A display device, comprising
a light source and a light emitting element comprising the cadmium free quantum dots of claim 1 , wherein the light emitting element and the light source is configured to provide the light emitting element with incident light.

21 . The display device of claim 20 , wherein, the light source comprises a plurality of light emitting unit, and each light emitting unit of the light source emit blue light, green light, or a combination thereof.

22 . The display device of claim 20 , wherein the display device comprises an organic light emitting diode as the light source, a first optical filter cutting blue light, green light or a combination thereof, a second optical filter reflecting light of a wavelength of greater than 500 nanometers, a liquid crystal layer, or a combination thereof.

23 . The display device of claim 20 , wherein the light emitting element comprises
a sheet of the quantum dot polymer composite, or a stacked structure comprising a substrate and a light emitting layer disposed on the substrate, wherein the light emitting layer comprises a pattern of the quantum dot polymer composite and the pattern comprises a first section configured to emit a first light, a second section configured to emit a second light having a different center wavelength from the first light, or a combination thereof.

24 . A quantum dot polymer composite comprising a polymer matrix and a plurality of cadmium free quantum dots dispersed in the polymer matrix,
wherein each of the cadmium free quantum dots has a core comprising a first semiconductor nanocrystal comprising indium and phosphorus and a semiconductor nanocrystal shell comprising zinc, selenium, and sulfur, wherein in the plurality of cadmium free quantum dots, a mole ratio of selenium with respect to indium is from about 4:1 to about 6:1, wherein the quantum dot polymer composite is in a form of sheet, and a thickness of the sheet is greater than or equal to about 10 um and less than or equal to about 1,000 um.

25 . The display device of claim 24 , wherein the quantum dot polymer composite show a blue light absorption rate of greater than or equal to about 82% with respect to light having a wavelength of about 450 nanometers.

26 . The display device of claim 24 , wherein the quantum dot polymer composite show a blue light absorption rate of greater than or equal to about 88% with respect to light having a wavelength of about 450 nanometers.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Won Yuho
• Won Nayoun
• Hwang Sungwoo
• Jang Eun Joo
• Kwon Soo Kyung
• Kim Yong Wook
• MIN Jihyun
• Park Garam
• Park Shang Hyeun
• Jang Hyo Sook
• Jun Shin Ae
• Han Yong Seok

Classifications

• B82Y20/00 Primary

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

• H10H20/8512

  Wavelength conversion materials · CPC title

• C09K11/883 Primary

  with zinc or cadmium · CPC title

• C09K11/025

  non-luminescent particle coatings or suspension media · CPC title

• G03F7/004

  Photosensitive materials (G03F7/12, G03F7/14 take precedence) · CPC title