Highly luminescent color-selective nanocrystalline materials
A nanocrystal capable of light emission includes a nanoparticle having photoluminescence having quantum yields of greater than 30%.
1. A composition comprising a population of nanocrystals, wherein each nanocrystal of the population comprises a core including a first semiconductor material and an overcoating including a second semiconductor material deposited on the core, wherein the population exhibits a photoluminescence quantum yield of at least 30% and emits light in a spectral range of about 30 nm or less full width at half max (FWHM) when irradiated.
2. The composition of claim 1 , wherein the population exhibits a photoluminescence quantum yield of at least 40%.
3. The composition of claim 1 , wherein the population exhibits a photoluminescence quantum yield of about 50%.
4. The composition of claim 1 , wherein the FWHM and quantum yield are determined at room temperature.
5. The composition of claim 1 , wherein the cores of the population have diameters having no greater than 10% rms deviation.
6. The composition of claim 1 , wherein the cores of the population have diameters having no greater than 5% rms deviation.
7. The composition of claim 1 , wherein the spectral range has a peak in the range of about 470 nm to about 625 nm.
8. The composition of claim 1 , wherein each of the cores has a diameter in the range of about 20 Angstroms to about 125 Angstroms.
9. The composition of claim 1 , wherein the core comprises CdSe.
10. The composition of claim 9 , wherein the overcoating comprises ZnS.
11. The composition of claim 1 , wherein the overcoating has a uniform thickness over the entire nanocrystal.
12. A composition comprising a population of nanocrystals, wherein each nanocrystal of the population comprises a core including a first semiconductor material and an overcoating including a second semiconductor material deposited on the core, wherein the population exhibits photoluminescence having a quantum yield of at least 30% and the cores of the population have diameters having no greater than 5% rms deviation.
13. The composition of claim 12 , wherein the population exhibits a photoluminescence quantum yield of at least 40%.
14. The composition of claim 12 , wherein the population exhibits a photoluminescence quantum yield of about 50%.
15. The composition of claim 12 , wherein the population of nanocrystals emits light in a spectral range of no greater than about 40 nm full width at half max (FWHM) when irradiated.
16. The composition of claim 12 , wherein the population of nanocrystals emits light in a spectral range of no greater than about 30 nm full width at half max (FWHM) when irradiated.
17. The composition of claim 12 , wherein the FWHM and quantum yield are determined at room temperature.
18. The composition of claim 12 , wherein the FWHM and quantum yield are determined at room temperature.
19. The composition of claim 12 , wherein the population of nanocrystals has a spectral range with a peak in the range of about 470 nm to about 621 nm when irradiated.
20. The composition of claim 12 , wherein each of the cores has a diameter in the range of about 21 Angstroms to about 125 Angstroms.
21. The composition of claim 12 , wherein the core comprises CdSe.
22. The composition of claim 12 , wherein the overcoating comprises ZnS.
23. The composition of claim 12 , wherein the overcoating has a uniform thickness over the entire core.
24. A composition comprising a population of nanocrystals, wherein the population comprises at least a first subpopulation of nanocrystals and a second subpopulation of nanocrystals,
wherein each nanocrystal of the first and second subpopulation comprises a core including a first semiconductor material and an overcoating including a second semiconductor material deposited on the core, wherein the cores of the first population are monodisperse and the cores of the second population are monodisperse, wherein the cores of the first subpopulation differ in size from the cores of the second subpopulation;
wherein the first and second subpopulations exhibit photoluminescence quantum yields of at least 30%; and
wherein the first and second subpopulations each emit light in a spectral range of about 40 nm or less full width at half max (FWHM) when irradiated.
25. The composition of claim 24 , wherein the first subpopulation and the second subpopulation each emits light in a spectral range of about 30 nm or less full width at half max (FWHM) when irradiated.
26. The composition of claim 25 , wherein the FWHM is determined at room temperature.
27. The composition of claim 24 , wherein the population exhibits a photoluminescence quantum yield of at least 40%.
28. The composition of claim 27 , wherein the quantum yield is determined at room temperature.
29. The composition of claim 24 , wherein the population exhibits a photoluminescence quantum yield of about 50%.
30. The composition of claim 29 , wherein the quantum yield is determined at room temperature.
31. The composition of claim 24 , wherein the cores of the first and second subpopulation comprise CdSe.
32. The composition of claim 31 , wherein the overcoating of the first and second subpopulation comprises ZnS.
33. The composition of claim 24 , wherein the cores of the first and/or second subpopulation have diameters having no greater than 10% rms deviation.
34. The composition of claim 24 , wherein the cores of the first and/or second subpopulation have diameters having no greater than 5% rms deviation.
35. The composition of claim 24 , wherein the FWHM is determined at room temperature.
36. The composition of claim 24 , wherein the quantum yield is determined at room temperature.
37. The composition of claim 24 , wherein the spectral ranges of the first and second subpopulations each have peaks in the range of about 470 nm to about 625 nm, wherein the peaks of the first and second subpopulations are distinct.
38. The composition of claim 24 , wherein the cores of the first subpopulation have a diameter between 20 and 50 angstroms and the cores in the second subpopulation have a diameter between 50 and 125 angstroms.