Quantum dots, composites, and device including the same
A quantum dot, and a quantum dot composite and a device including the same, wherein the quantum dot includes a seed including a first semiconductor nanocrystal, a quantum well layer disposed on the seed and a shell disposed on the quantum well layer, 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), and gallium (Ga), 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.
1. A quantum dot comprising
a seed comprising a first semiconductor nanocrystal,
a quantum well layer disposed on the seed, 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, and gallium,
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, and
wherein in the quantum dot, a mole ratio of gallium with respect to a sum of indium and gallium is greater than or equal to about 0.01:1 and less than or equal to about 0.5:1.
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, and
the second semiconductor nanocrystal comprises ZnSe, ZnSeS, ZnS, or a combination thereof.
5. The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of gallium with respect to a sum of indium and gallium is greater than or equal to about 0.05:1 and less than or equal to about 0.3:1.
6. 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 10:1 and less than or equal to about 30:1.
7. The quantum dot of claim 1 , wherein the first semiconductor nanocrystal and the second semiconductor nanocrystal comprise selenium, and in the quantum dot, a mole ratio of selenium respect to a sum of indium and gallium is less than or equal to about 15:1.
8. The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of phosphorus with respect to a sum of indium and gallium is greater than or equal to about 0.5:1 and less than or equal to about 1.3:1.
9. The quantum dot of claim 1 , wherein in the quantum dot, a mole ratio of indium and gallium with respect to a sum of chalcogen elements is greater than or equal to about 0.03:1 and less than or equal to about 0.2:1.
10. The quantum dot of claim 1 , wherein the shell comprises
a first layer comprising a third zinc chalcogenide, and
a second layer disposed on the first layer and comprising a fourth zinc chalcogenide having a different composition from the third zinc chalcogenide.
11. The quantum dot of claim 10 , wherein
the first layer is directly on the quantum well layer, and
the second layer is an outermost layer of the shell.
12. 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 20 nanometers.
13. 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.
14. The quantum dot of claim 1 , wherein 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.
15. 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 545 nanometers.
16. A quantum dot polymer composite comprising
a polymer matrix; and
a plurality of quantum dots of claim 1 dispersed in the polymer matrix.
17. The quantum dot-polymer composite of claim 16 , wherein the quantum dot polymer composite is in a form of a patterned film.
18. The quantum dot-polymer composite of claim 16 , wherein the quantum dot polymer composite exhibits an absorption of greater than or equal to about 90% for blue light.
19. A display device, comprising
a light emitting element, and optionally a light source,
wherein the light emitting element comprises the quantum dot-polymer composite of claim 16 , and if present, the light source is configured to provide a photoluminescence element with incident light.
20. The display device of claim 19 , 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.