Metal doped semiconductor nanocrystals and methods of making the same

1. A colloidal doped semiconductor nanocrystal comprising:

a III/V host semiconductor material; and

metal dopant, wherein the colloidal semiconductor nanocrystal has a dopant emission greater than about 620 nm, wherein the III/V host semiconductor material comprises InP, and wherein the metal dopant comprises Cu.

2. The doped semiconductor nanocrystal of claim 1 having a photoluminescence quantum yield of at least about 5%.

3. The doped semiconductor nanocrystal of claim 1 having substantially no bandgap emission from the III/V host semiconductor material.

4. The doped semiconductor nanocrystal of claim 1 , wherein the metal dopant is incorporated into the lattice of the III/V host semiconductor material.

5. The doped semiconductor nanocrystal of claim 1 , wherein the metal dopant is present in an amount of at least about 1 atomic weight percent.

6. The doped semiconductor nanocrystal of claim 1 , wherein the metal dopant has a plurality of emission bands.

7. The doped semiconductor nanocrystal of claim 1 further comprising a diffusion barrier at least partially surrounding the III/V host semiconductor material.

8. The doped semiconductor nanocrystal of claim 7 , wherein the diffusion barrier comprises a second semiconductor material.

9. The doped semiconductor nanocrystal of claim 8 , wherein the second semiconductor material comprises 2 to 20 monolayers of ZnSe.

10. The doped semiconductor nanocrystal of claim 9 , wherein the doped semiconductor nanocrystal has a size up to about 10 nm.

11. The doped semiconductor nanocrystal of claim 7 having a photoluminescence quantum yield of at least about 5%.

12. The doped semiconductor nanocrystal of claim 7 , wherein the doped semiconductor nanocrystal has a size less than about 10 nm.

13. The doped semiconductor nanocrystal of claim 9 , wherein the second semiconductor material comprises at least 3 monolayers of ZnSe and the dopant photoluminescent quantum yield is greater than 20%.

14. A method of producing colloidal doped semiconductor nanocrystals comprising:

(a) combining a group III metal precursor, a ligand and a solvent to form a metal-ligand complex in a reaction vessel;

(b) admixing an anionic precursor comprising a group V element with the metal-ligand complex at a first temperature sufficient to form colloidal host semiconductor nanocrystals comprising a III/V semiconductor material;

(c) admixing a metal dopant with the host semiconductor nanocrystals to provide a reaction mixture; and

(d) heating the reaction mixture to a second temperature to provide colloidal host semiconductor nanocrystals having the dopant dispersed therein,

wherein the III/V semiconductor material comprises InP, and

wherein the dopant comprises Cu.

15. The method of claim 14 , wherein the first temperature ranges from about 180° C. to about 190° C.

16. The method of claim 14 , wherein the second temperature ranges from about 175° C. to about 240° C.

17. The method of claim 16 , wherein the reaction mixture is heated at a rate of at least about 2° C./minute.

18. The method of claim 14 , wherein the doped semiconductor nanocrystals are substantially monodisperse.

19. The method of claim 14 further comprising forming a diffusion barrier comprising a material M 1 X 1 on at least one of the doped semiconductor nanocrystals.

20. The method of claim 19 , wherein forming the diffusion barrier comprising the material M 1 X 1 on the at least one doped semiconductor nanocrystal comprises forming at least one monolayer of the material M 1 X 1 on the at least one doped semiconductor nanocrystal by contacting the doped semiconductor nanocrystal, in an alternating manner, with a cation (M 1 ) precursor solution in an amount to form a monolayer of cation and an anion precursor (X 1 ) in an amount to form a monolayer of anion, wherein M 1 X 1 comprises an inorganic solid selected from a group II/VI compound or a III/V compound.

21. The method of claim 19 , wherein, prior to forming the diffusion barrier, the doped semiconductor nanocrystals have a dopant concentration of greater than 10% to about 20%, based on the total cations of a core of the doped semiconductor nanocrystals.

22. The method of claim 19 , wherein the doped semiconductor nanocrystals have substantially no bandgap emission from the III/V host semiconductor material or the diffusion barrier.

23. The method of claim 19 , wherein M 1 X 1 comprises a II/VI compound.

24. The method of claim 23 , wherein the II/VI compound comprises ZnSe.

25. The method of claim 21 , wherein forming a diffusion barrier further comprises ejecting some metal dopant from the at least one semiconductor nanocrystal.

26. The doped semiconductor nanocrystal of claim 1 having a dopant emission in the near infrared region of the electromagnetic spectrum.

27. The method of claim 14 , wherein the doped semiconductor nanocrystals have a dopant emission in the near infrared region of the electromagnetic spectrum.