Core shell quantum dot, production method thereof, and electronic device including the same
A core shell quantum dot including a core including a first semiconductor nanocrystal and including zinc, tellurium, and selenium and a semiconductor nanocrystal shell disposed on the core and including a zinc chalcogenide, a method of manufacture thereof, and a device including the same are disclosed, wherein the core shell quantum dot does not include cadmium, lead, mercury, or a combination thereof, wherein in an X-ray photoelectron spectrum of the quantum dot, a peak area for Te oxide to a peak area for Te3d 5/2 as an area percentage is less than or equal to about 25%.
1. A core shell quantum dot comprising a core comprising a first semiconductor nanocrystal comprising zinc, tellurium, and selenium, and a semiconductor nanocrystal shell disposed on the core, the shell comprising a zinc chalcogenide,
wherein the core shell quantum dot does not comprise cadmium, lead, mercury, or a combination thereof,
wherein in an X-ray photoelectron spectrum of the core shell quantum dot, a peak area for a Te oxide to a peak area for Te3d 5/2 as an area percentage is less than or equal to about 25%.
2. The core shell quantum dot of claim 1 , wherein the core shell quantum dot has a mole ratio of tellurium to selenium that is greater than about 0.1:1.
3. The core shell quantum dot of claim 1 , wherein the core shell quantum dot has a mole ratio of tellurium to selenium that is less than or equal to about 4:1.
4. The core shell quantum dot of claim 1 , wherein the peak area for a Te oxide to the peak area for Te3d 5/2 as an area percentage is less than or equal to about 20%.
5. The core shell quantum dot of claim 1 , wherein the core-shell quantum dot further comprises an additional metal, and the additional metal comprises aluminum, gallium, lithium, or a combination thereof.
6. The core shell quantum dot of claim 5 , wherein the core-shell quantum dot has a mole ratio of the additional metal to the tellurium that is greater than or equal to about 0.001 and less than or equal to about 1.5.
7. The core shell quantum dot of claim 1 , wherein the core shell quantum dot does not comprise an indium phosphide.
8. The core shell quantum dot of claim 1 , wherein the core shell quantum dot is water insoluble.
9. The core shell quantum dot of claim 1 , wherein the zinc chalcogenide comprises selenium, sulfur, or a combination thereof.
10. The core shell quantum dot of claim 1 , wherein the core shell quantum dot has a mole ratio of sulfur to selenium that is greater than 0:1 and less than or equal to about 4:1.
11. The core shell quantum dot of claim 1 , wherein the core shell quantum dot has a mole ratio of sulfur to tellurium that is greater than 0.5:1 and less than or equal to about 3:1.
12. The core shell quantum dot of claim 1 , wherein a maximum luminescent peak wavelength of the core shell quantum dot is in a range of greater than about 450 nanometers and less than or equal to about 600 nanometers.
13. The core shell quantum dot of claim 1 , wherein the maximum photoluminescent peak of the core shell quantum dot has a full width at half maximum of less than or equal to about 30 nanometers.
14. The core shell quantum dot of claim 1 , the core shell quantum dot has a quantum efficiency of greater than or equal to about 35%.
15. The core shell quantum dot of claim 1 , wherein the core shell quantum dot comprises an organic ligand and the organic ligand 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′, RHPO(OH), RPO(OH) 2 , R 2 POOH, a polymeric organic ligand, or a combination thereof, wherein R and R′ are the same or different, and are each independently a substituted or unsubstituted C1 to C40 aliphatic hydrocarbon group, a substituted or unsubstituted C6 to C40 aromatic hydrocarbon group, or a combination thereof.
16. A method of manufacturing the core shell quantum dot of claim 1 , the method comprising:
preparing a core particle by reacting a zinc precursor, a selenium precursor, and a tellurium precursor at a core formation temperature to form a first semiconductor nanocrystal; and adding a treating agent to a reaction medium including the first semiconductor nanocrystal for a post-treatment;
wherein the treating agent comprises an organic thiol compound, sulfur dispersed in a (C1 to C20 alkyl)phosphine, a bis(trialkylsilyl) sulfide, a metal compound, or a combination thereof; and
reacting a zinc precursor with a chalcogen element precursor at a shell formation temperature in the presence of the core particle and a shell formation organic ligand to form a semiconductor nanocrystal shell on the core particle.
17. The method of claim 16 , wherein the organic thiol compound comprises a compound represented by RSH, wherein R is an unsubstituted C1 to C30 hydrocarbon group, and
wherein the metal compound comprises a metal halide, an organic carboxylate-metal compound, an organic amine-metal compound, a reaction product of a metal carboxylate with a sulfur compound, or a combination thereof.
18. The method of claim 16 , wherein the core formation temperature is greater than or equal to about 280° C. and the post treatment is carried out a temperature of greater than or equal to about 50° C. and less than the core formation temperature.
19. A quantum dot composite comprising a matrix and a plurality of quantum dots dispersed in the matrix, wherein the plurality of quantum dots includes the core-shell quantum dot of claim 1 .
20. A display device comprising
a light emitting element,
wherein the light emitting element comprises a plurality of core shell quantum dots, wherein the plurality of quantum dots includes the core-shell quantum dot of claim 1 .
21. An electronic device comprising:
a first electrode and a second electrode each having a surface opposite the other, and
an active layer disposed between the first electrode and the second electrode, the active layer comprising a plurality of quantum dots, wherein the plurality of quantum dots includes the core-shell quantum dot of claim 1 .