Quantum dots, a composition or composite including the same, and an electronic device including the same
A cadmium free quantum dot including a semiconductor nanocrystal core and a semiconductor nanocrystal shell disposed on the core, wherein the quantum dot does not include cadmium and includes indium and zinc, the quantum dot has a maximum photoluminescence peak in a red light wavelength region, a full width at half maximum (FWHM) of the maximum photoluminescence peak is less than or equal to about 40 nanometers (nm), an ultraviolet-visible (UV-Vis) absorption spectrum of the quantum dot includes a valley between about 450 nm to a center wavelength of a first absorption peak, and a valley depth (VD) defined by the following equation is greater than or equal to about 0.2, a quantum dot polymer composite including the same, and a display device including the quantum dot-polymer composite: (Abs first −Abs valley )/Abs first =VD.
1. A quantum dot composite pattern comprising a first color section,
wherein the first color section comprises a first quantum dot composite comprising a matrix and cadmium free quantum dots dispersed in the matrix,
wherein the cadmium free quantum dots comprise indium and phosphorus,
wherein the cadmium free quantum dots do not comprise cadmium,
wherein the cadmium free quantum dots are configured to emit a first light having a maximum photoluminescence peak in a red light wavelength region of greater than or equal to about 600 nanometers and less than or equal to about 650 nanometers,
wherein in an ultraviolet-visible absorption spectrum, the cadmium free quantum dots are configured to exhibit a first absorption peak having a half width at half maximum of less than or equal to about 25 nanometers.
2. The quantum dot composite pattern of claim 1 , wherein the half width at half maximum of the first absorption peak is less than or equal to about 24 nanometers.
3. The quantum dot composite pattern of claim 1 , wherein the half width at half maximum of the first absorption peak is less than or equal to about 23 nanometers.
4. The quantum dot composite pattern of claim 1 , wherein in the ultraviolet-visible absorption spectrum of the cadmium free quantum dot, a valley depth defined by the following equation is greater than or equal to about 0.2:
(Abs first −Abs valley )/Abs firsi =valley depth
wherein, Abs first is an absorption intensity at the first absorption peak wavelength and Abs valley is an absorption intensity at a lowest point of the valley.
5. The quantum dot composite pattern of claim 4 , wherein the valley depth is from about 0.35 to 0.449.
6. The quantum dot composite pattern of claim 4 , wherein the valley depth is from about 0.2 to 0.449.
7. The quantum dot composite pattern of claim 1 , wherein the cadmium free quantum dots further comprise zinc, selenium, sulfur, or a combination thereof.
8. The quantum dot composite pattern of claim 1 , wherein the cadmium free quantum dots further comprise zinc, selenium, and sulfur.
9. The quantum dot composite pattern of claim 1 , wherein the first absorption peak is present in a range of greater than or equal to about 580 nanometers and less than or equal to about 650 nanometers.
10. The quantum dot composite pattern of claim 1 , wherein the first absorption peak is present in a range of greater than or equal to about 600 nanometers and less than or equal to about 630 nanometers and the red light wavelength region is greater than or equal to about 610 nanometers and less than or equal to about 640 nanometers.
11. The quantum dot composite pattern of claim 1 , wherein the first quantum dot composite further comprises a metal oxide particulate.
12. The quantum dot composite pattern of claim 1 , further comprising a second color section that is configured to emit a second light different from the first light and optionally wherein a black matrix is disposed between the second color section and the first color section.
13. The quantum dot composite pattern of claim 12 , wherein the second color section comprises a second quantum dot composite comprising a matrix and quantum dots configured to emit the second light.
14. The quantum dot composite pattern of claim 1 , wherein a thickness of the first quantum dot composite is greater than or equal to about 2 micrometers and less than or equal to about 30 micrometers.
15. The quantum dot composite pattern of claim 1 , wherein the first quantum dot composite is configured to show a photoconversion efficiency of from about 20% to 30%.
16. A stacked structure comprising a substrate, the quantum dot composite pattern of claim 1 , and optionally an optical element disposed between the substrate and the first color section of the quantum dot composite pattern, wherein if present, the optical element is configured to reflect or absorb blue light and optionally green light.
17. A display device comprising the stacked structure of claim 16 and a light source, wherein the light source is configured to provide the quantum dot composite pattern with incident light.
18. A display device comprising the quantum dot composite pattern of claim 1 and a light source, and
wherein the light source is configured to provide the quantum dot composite pattern with incident light.
19. The display device of claim 18 , wherein the quantum dot composite pattern further comprises a second color section that is configured to emit a second light different from the first light, and wherein the light source comprises a plurality of light emitting units each corresponding to the first color section and the second color section, respectively.
20. The display device of claim 18 , wherein the light source comprises a first electrode, a second electrode, and a luminescent layer disposed between the first electrode and the second electrode.