Quantum dots, compositions or composites including the same, patternized layer, and display device including the same

1. A quantum dot, comprising

a core comprising a first semiconductor nanocrystal comprising a Group III-V compound; and

a semiconductor nanocrystal shell disposed on the core, the semiconductor nanocrystal shell comprising zinc, tellurium, and selenium,

wherein the quantum dot does not comprise cadmium, and

wherein the semiconductor nanocrystal shell has a mole ratio of tellurium to selenium of less than about 0.025:1.

2. The quantum dot of claim 1 , wherein the semiconductor nanocrystal shell has a mole ratio of tellurium to selenium of less than or equal to about 0.02:1.

3. The quantum dot of claim 1 , wherein the semiconductor nanocrystal shell has a mole ratio of tellurium to selenium of greater than or equal to about 0.005:1.

4. The quantum dot of claim 1 , wherein the semiconductor nanocrystal shell has a composition that changes in a radial direction.

5. The quantum dot of claim 1 , wherein the semiconductor nanocrystal shell comprises a first layer disposed directly on the core, and an outer layer disposed on the first layer, and

wherein the first layer comprises a second semiconductor nanocrystal and the outer layer has a different composition from the second semiconductor nanocrystal.

6. The quantum dot of claim 5 , wherein the second semiconductor nanocrystal comprises zinc and selenium, and the outer layer comprises

zinc, and

sulfur, selenium, or a combination thereof.

7. The quantum dot of claim 6 , wherein the second semiconductor nanocrystal further comprises tellurium, and the outer layer comprises sulfur, and

wherein a concentration of tellurium in the semiconductor nanocrystal shell decreases in a direction toward a surface of the quantum dot, and a concentration of sulfur increases in a direction toward the surface of the quantum dot.

8. The quantum dot of claim 5 , wherein the outer layer comprises a first outer layer disposed directly on the first layer and an outermost layer of the quantum dot, and

wherein the first outer layer comprises a third semiconductor nanocrystal comprising zinc and selenium, and the outermost layer comprises a fourth semiconductor nanocrystal comprising zinc and sulfur and no selenium.

9. The quantum dot of claim 8 , wherein the third semiconductor nanocrystal further comprises tellurium.

10. The quantum dot of claim 1 , wherein the core comprises indium and phosphorus.

11. The quantum dot of claim 10 , wherein the core further comprises zinc.

12. The quantum dot of claim 10 , wherein the quantum dot has an emission peak wavelength in a range of about 500 nanometers to about 550 nanometers, and a mole ratio of tellurium to indium is greater than or equal to about 0.1:1.

13. The quantum dot of claim 12 , wherein a quantum efficiency of the quantum dot is greater than or equal to about 58% and a full width at half maximum of a photoluminescence emission peak of the quantum dot is less than or equal to about 45 nanometers.

14. The quantum dot of claim 1 , wherein the quantum dot has an emission peak wavelength in the range of about 600 nanometers to about 650 nanometers and a mole ratio of tellurium to indium is greater than or equal to about 0.01:1.

15. The quantum dot of claim 14 , wherein a quantum efficiency of the quantum dot is greater than or equal to about 70% and a full width at half maximum of a photoluminescence emission peak of the quantum dot is less than about 45 nanometers.

16. The quantum dot of claim 1 , wherein the quantum dot comprises RCOOH, RNH 2 , R 2 NH, R 3 N, RSH, RH 2 PO, R 2 HPO, R 3 PO, RH 2 P, R 2 HP, R 3 P, ROH, RCOOR, RPO(OH) 2 , RPOOH, RHPOOH, R 2 POOH, wherein R is the same or different and is independently a substituted or unsubstituted C1 to C40 aliphatic hydrocarbon, a substituted or unsubstituted C6 to C40 aromatic hydrocarbon, or a combination thereof, provided that at least one R is not hydrogen, or a combination thereof, on a surface thereof.

17. A composition comprising

a plurality of the quantum dots of claim 1 ,

a dispersing agent,

a polymerizable monomer comprising a carbon-carbon unsaturated bond, and

an initiator.

18. The composition of claim 17 , wherein the dispersing agent is a polymer comprising a carboxylic acid group, the polymer comprising

a copolymer of a monomer mixture comprising a first monomer comprising a carboxylic acid group and a carbon-carbon double bond, a second monomer comprising a carbon-carbon double bond and a hydrophobic moiety and not comprising a carboxylic acid group, and optionally a third monomer comprising a carbon-carbon double bond and a hydrophilic moiety and not comprising a carboxylic acid group;

a multiple aromatic ring-containing polymer having a backbone structure in which two aromatic rings are bound to a quaternary carbon atom that is a constituent atom of another cyclic moiety in the main chain and comprising a carboxylic acid group (—COOH); or

a combination thereof.

19. The composition of claim 17 , wherein the composition further comprises a multi-thiol compound comprising at least two thiol groups at a terminal end of the multi-thiol compound, metal oxide particulates, or a combination thereof.

20. The composition of claim 19 , wherein the metal oxide particulates comprise TiO 2 , SiO 2 , BaTiO 3 , Ba 2 TiO 4 , ZnO, or a combination thereof.

21. The composition of claim 19 , wherein the multi-thiol compound comprises a compound represented by Chemical Formula 1:

wherein, in Chemical Formula 1,

R 1 is hydrogen; a substituted or unsubstituted C1 to C30 linear or branched alkyl group; a substituted or unsubstituted C6 to C30 aryl group; a substituted or unsubstituted C3 to C30 heteroaryl group; a substituted or unsubstituted C3 to C30 cycloalkyl group; a substituted or unsubstituted C3 to C30 heterocycloalkyl group; a C1 to C10 alkoxy group; a hydroxy group; —NH 2 ; a substituted or unsubstituted C1 to C30 amine group; an isocyanate group; a halogen; —ROR′, wherein R is a substituted or unsubstituted C1 to C20 alkylene group and R′ is hydrogen or a C1 to C20 linear or branched alkyl group; an acyl halide; —C(═O)OR′, wherein R′ is hydrogen or a C1 to C20 linear or branched alkyl group; —CN; —C(═O)ORR′ or —C(═O)ONRR′, wherein R and R′ are independently hydrogen or a C1 to C20 linear or branched alkyl group,

L 1 is a carbon atom, a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C1 to C30 alkylene group wherein at least one methylene is replaced by a sulfonyl, a carbonyl, an ether, a sulfide, a sulfoxide, an ester, an amide, or a combination thereof, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C6 to C30 arylene group, a substituted or unsubstituted C3 to C30 heteroarylene group, or a substituted or unsubstituted C3 to C30 heterocycloalkylene moiety,

Y 1 is a single bond; a substituted or unsubstituted C1 to C30 alkylene group; a substituted or unsubstituted C2 to C30 alkenylene group; or a C1 to C30 alkylene group or a C2 to C30 alkenylene group wherein at least one methylene is replaced by a sulfonyl, a carbonyl, an ether, a sulfide, a sulfoxide, an ester, an amide, an imine, or a combination thereof,

m is an integer of 1 or greater,

k1 is an integer of 0 or 1 or greater,

k2 is an integer of 1 or greater,

a sum of m and k2 is an integer of 3 or greater,

m does not exceed a valence of Y 1 , and

a sum of k1 and k2 does not exceed a valence of L 1 .

22. A quantum dot-polymer composite comprising

a polymer matrix; and

a plurality of the quantum dots of claim 1 dispersed in the polymer matrix,

wherein the polymer matrix comprises a binder polymer, a polymerization product of a photopolymerizable monomer comprising at least one carbon-carbon double bond, and optionally a polymerization product between the photopolymerizable monomer and a multi-thiol compound comprising at least two thiol groups at a terminal end of the multi-thiol compound.

23. A patterned layer comprising

a repeating section configured to emit light in a predetermined wavelength,

wherein the repeating section comprises the quantum dot-polymer composite of claim 22 .

24. The patterned layer of claim 23 , wherein the re-peating section comprises a first section configured to emit red light, a second section configured to emit green light, or a combination thereof.

25. A display device comprising a light source and a light emitting element,

wherein the light emitting element comprises a substrate, and the patterned layer of claim 23 disposed on the substrate, and

wherein the light source is configured to provide the light emitting element with incident light.

26. The display device of claim 25 , wherein the incident light has an emission peak wavelength of about 440 nanometers to about 460 nanometers.