Patent application EP20180699A (EP), filed 2020-06-18
Publication number: EP3753996A1
Title: QUANTUM DOTS, A COMPOSITION OR COMPOSITE INCLUDING THE SAME, AND AN ELECTRONIC DEVICE INCLUDING THE SAME
Abstract: A quantum dot, and a composite and a display device including the quantum dot. The quantum dot comprises a semiconductor nanocrystal core comprising indium and phosphorous, a semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core, the first semiconductor nanocrystal shell comprising zinc, selenium, and sulfur, wherein the quantum dot does not comprise cadmium wherein the quantum dot has a maximum photoluminescence peak in a green light wavelength region, and wherein in an ultraviolet-visible (UV-Vis) absorption spectrum of the quantum dot, a ratio A<sub>450</sub>/A<sub>first</sub>, of an absorption value at 450 nm to an absorption value at a first excitation peak is greater than or equal to about 0,7, and a valley depth (VD) defined by the following equation is greater than or equal to about 0.4: Absfirst−Absvalley/Absfirst=VD wherein, Abs<sub>first</sub> is an absorption value at the first absorption peak wavelength and Abs<sub>valley</sub> is an absorption value at a lowest point of the valley adjacent to the first absorption peak.
IPC codes: C09K  11/    02            A I
C09K  11/    56            A I
C09K  11/    70            A I
C09K  11/    88            A I
H01L  51/    50            A I
H05B  33/    14            A I
Claims: number: 1
text: A 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 quantum dot has a maximum photoluminescence peak in a green light wavelength region, and in an ultraviolet-visible absorption spectrum of the quantum dot, a ratio A<450>/A<first>, of an absorption value at 450 nanometers to an absorption value of a first excitation peak is greater than or equal to 0.7, and a valley depth (VD) defined by the following equation is greater than or equal to 0.4:  Abs first − Abs valley / Abs first = VD
number: 2
text: The quantum dot of Claim 1, wherein the semiconductor nanocrystal core further comprises zinc.
number: 3
text: The quantum dot of Claims 1 or 2, wherein in the quantum dot, a mole ratio of sulfur with respect to selenium (S/Se) is less than or equal to 2.5:1, preferably
less than or equal to 0.8:1, and/or
wherein in the quantum dot, a mole ratio of zinc with respect to indium is greater than or equal to 10:1 and less than or equal to 50:1; and/or
wherein in the quantum dot, a mole ratio of a sum of selenium and sulfur with respect to indium (S+Se)/ln is greater than or equal to 10:1 and less than or equal to 40:1, preferably,
greater than or equal to 20:1 and less than or equal to 38:1.
number: 4
text: The quantum dot of any of Claims 1-3, wherein the semiconductor nanocrystal shell comprises a first shell layer including zinc and selenium, and a second shell layer disposed on the first shell layer and including zinc and sulfur;
preferably wherein the second shell layer does not comprise selenium and the second shell layer is an outermost layer of the quantum dot.
number: 5
text: The quantum dot of any of Claims 1-4, wherein the green light wavelength region is greater than or equal to 500 nm and less than or equal to 560 nanometers; and/or
wherein in the quantum dot, a mole ratio of zinc with respect to indium is greater than or equal to 26:1 and less than or equal to 45:1.
number: 6
text: The quantum dot of any of Claims 1-5, wherein the first absorption peak is in a wavelength range of greater than 450 nanometers and less than or equal to the wavelength of the maximum photoluminescent peak;
preferably wherein the first absorption peak is in a wavelength range of greater than 455 nanometers.
number: 7
text: The quantum dot of any of Claims 1-6, wherein the valley adjacent to the first absorption peak is present in a range of greater than or equal to 420 nanometers and less than or equal to 490 nanometers; and/or
wherein the ratio of the absorption value at 450 nanometers to the absorption value at the first absorption peak is greater than or equal to 0.75; and/or
wherein the valley depth is greater than or equal to 0.5.
number: 8
text: The quantum dot of any of Claims 1-7, wherein the quantum dot is present as a plurality of quantum dots having an average size of greater than or equal to 4 nanometers and less than or equal to 8 nanometers and a standard deviation of less than or equal to 30% of the average size; and/or
wherein the maximum photoluminescence peak of the quantum dot exhibits a full width at half maximum of less than or equal to 50 nanometers; and/or
wherein a quantum efficiency of the quantum dot is greater than or equal to 84%.
number: 9
text: A quantum dot-polymer composite comprising:
number: 10
text: The quantum dot-polymer composite of Claim 9, wherein the quantum dot polymer composite comprises a blue light conversion rate of greater than or equal to 29% after being thermally-treated at a temperature of 180 °C for 30 minutes.
number: 11
text: The quantum dot-polymer composite of Claims 9 or 10, wherein the polymer matrix comprises a crosslinked polymer, a linear polymer having a carboxylic acid group, or a combination thereof;
preferably wherein the crosslinked polymer comprises a polymerization product of a monomer having at least two carbon-carbon double bond, a polymerization product of the monomer and a poly thiol compound including at least two thiol groups, or a combination thereof.
number: 12
text: The quantum dot-polymer composite of any of Claims 9-11, further comprising metal oxide fine particles dispersed in the polymer matrix.
number: 13
text: A display device, comprising
a light source and a light emitting element,
wherein the light emitting element comprises the quantum dot-polymer composite of any of Claims 9-12, and the light source provides the light emitting element with incident light.
number: 14
text: The display device of Claim 13, wherein the incident light has a luminescence peak wavelength of 440 nanometers to 460 nanometers; and/or
wherein the light emitting element comprises a sheet including the quantum dot-polymer composite; and/or
wherein the light emitting element comprises a stacked structure comprising a substrate and a light emitting layer disposed on the substrate,
preferably wherein the light emitting layer comprises a pattern comprising the quantum dot-polymer composite.
number: 15
text: The display device of Claims 13 or 14, wherein the display device exhibits color reproducibility of greater than or equal to 80% based on BT2020.
Office action: search_report, dated 2020-12-23
Rejection reasons: novelty_epc_54
Prior art cited: ref_id: US2017059988A1
ref_type: patent
severity: background
ref_id: US2017183565A1
ref_type: patent
severity: background
ref_id: EP3184603A1
ref_type: patent
severity: background
ref_id: US2017306227A1
ref_type: patent
severity: background
ref_id: EP3184603
ref_type: patent
severity: novelty_destroying
ref_id: US2017183565
ref_type: patent
severity: novelty_destroying
ref_id: US2017306227
ref_type: patent
severity: novelty_destroying
Final disposition: pending (2020-12-23)