Semiconductor nanocrystals and compositions and devices including same
A semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light with an improved photoluminescence quantum efficiency. Also disclosed are populations of semiconductor nanocrystals, compositions and devices including a semiconductor nanocrystal capable of emitting light with an improved photoluminescence quantum efficiency. In one embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light upon excitation with a photoluminescence quantum efficiency greater than about 65%. In another embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising zinc, cadmium, and sulfur and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material. In a further embodiment, a semiconductor nanocrystal includes a core comprises a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material comprising at least three chemical elements, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation. In a further embodiment, a semiconductor nanocrystal including a core comprises a first semiconductor material comprising zinc, cadmium, and selenium and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation.
1. A device comprising a semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of a surface of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light upon excitation with a photoluminescence quantum efficiency greater than about 65%.
2. A device comprising a layer comprising a plurality of semiconductor nanocrystals and means for exciting the semiconductor nanocrystals, wherein at least a portion of the semiconductor nanocrystals comprise a semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of a surface of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light upon excitation with a photoluminescence quantum efficiency greater than about 65%.
3. A device including a semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material comprising at least three chemical elements, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation.
4. A device comprising a layer comprising plurality of semiconductor nanocrystals and means for exciting the semiconductor nanocrystals, wherein at least a portion of the semiconductor nanocrystals comprise a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material comprising at least three chemical elements, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation.
5. A device in accordance with claim 1 wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 80% upon excitation.
6. A device in accordance with claim 1 wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 90% upon excitation.
7. A device in accordance with claim 1 wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 95% upon excitation.
8. A device in accordance with claim 1 wherein the first semiconductor material comprises zinc, cadmium, and sulfur.
9. A device in accordance with claim 1 wherein the second semiconductor material comprises zinc and sulfur.
10. A device in accordance with claim 1 wherein the light includes a maximum peak emission with a full width at half maximum of not more than 40 nm.
11. A device in accordance with claim 1 wherein the light includes a maximum peak emission with a full width at half maximum of not more than 30 nm.
12. A device in accordance with claim 1 wherein the light includes a maximum peak emission with a full width at half maximum of not more than 20 nm.
13. A device in accordance with claim 1 wherein the device is a light-emitting device.
14. A device in accordance with claim 1 wherein the device is a display device.
15. A device in accordance with claim 2 wherein the means for exciting the semiconductor nanocrystals comprises a light source.
16. A device in accordance with claim 2 wherein the means for exciting the semiconductor nanocrystals comprises a first electrode disposed on a substrate and a second electrode opposed to the first electrode and the layer comprising semiconductor nanocrystals is disposed between the two electrodes and in electrical communication therewith.
17. A device in accordance with claim 3 wherein the light includes a maximum peak emission with a full width at half maximum of not more than 40 nm.
18. A device in accordance with claim 3 wherein the device is a light-emitting device.
19. A device in accordance with claim 3 wherein the first semiconductor material comprises zinc, cadmium, and selenium.
20. A device in accordance with claim 4 wherein the first semiconductor material comprises zinc, cadmium, and selenium.
21. A device in accordance with claim 3 wherein the device is a display device.