Ligand-sensitized lanthanide nanocrystals as ultraviolet downconverters

Patent metadata

Field	Value
Publication number	US-10982136-B2
Application number	US-201715442441-A
Country	US
Kind code	B2
Filing date	Feb 24, 2017
Priority date	Feb 26, 2016
Publication date	Apr 20, 2021
Grant date	Apr 20, 2021

Abstract

Embodiments relate generally to lanthanide nanocrystals as ultraviolet downconverters.

First claim

What is claimed is:

1. A light conversion material, comprising: a lanthanide nanocrystal and a HOPO containing chelator, wherein the lanthanide nanocrystal comprises NaGd 1-x Eu x F 4 , wherein x is between 0 and 1, wherein the HOPO containing chelator comprises 3,4,3-LI(1,2-HOPO), wherein 3,4,3-LI(1,2-HOPO) is attached to a surface of the lanthanide nanocrystal, wherein 3,4,3-LI(1,2-HOPO) is configured to downconvert light from UV to visible, and wherein the light conversion material is configured to provide for at least a two order of magnitude increase in light absorption by NaGd1-xEuxF4 as compared to light absorption by NaGd1-xEuxF4 without 3,4,3-LI(1,2-HOPO).

2. A photovoltaic cell comprising: a lanthanide nanocrystal and a HOPO containing chelator, wherein the lanthanide nanocrystal comprises NaGd 1-x Eu x F 4 , wherein x is between 0 and 1, wherein the HOPO containing chelator comprises 3,4,3-LI(1,2-HOPO), wherein 3,4,3-LI(1,2-HOPO) is attached to a surface of the lanthanide nanocrystal wherein 3,4,3-LI(1,2-HOPO) is configured to downconvert light from UV to visible, and wherein the photovoltaic cell is configured to provide for at least a two order of magnitude increase in light absorption by NaGd 1-x Eu x F 4 as compared to light absorption by NaGd 1-x Eu x F 4 without 3,4,3-LI(1,2-HOPO).

3. The photovoltaic cell of claim 2 , wherein the 3,4,3-LI(1,2-HOPO) is configured to downconvert UV radiation to near-infrared wavelengths.

4. The photovoltaic cell of claim 2 , wherein the lanthanide nanocrystal comprises NaGd 0.9 Eu 0.05 F 4 .

5. The photovoltaic cell of claim 2 , wherein the lanthanide is a luminescent lanthanide.

6. The photovoltaic cell of claim 2 , further comprising bulk silicon configured and positioned to absorb light emitted from the lanthanide nanocrystal.

7. A nanocrystal comprising:
a NaGd 1-x Eu x F 4 nanocrystal, wherein x is between 0 and 1; and
a 3,4,3-LI(1,2-HOPO) ligand.

8. The nanocrystal of claim 7 , wherein the 3,4,3-LI(1,2-HOPO) ligand coats a surface of the nanocrystal.

9. A method of downconverting light from UV to visible, the method comprising:
illuminating a 3,4,3-LI(1,2-HOPO) ligand with UV radiation such that the ligand absorbs energy in the UV spectrum; and
transfers energy to NaGd 1-x Eu x F 4 , wherein x is between 0 and 1,
wherein the method provides for at least a two order of magnitude increase in light absorption by NaGd 1-x Eu x F 4 as compared to light absorption by NaGd 1-x Eu x F 4 without 3,4,3-LI(1,2-HOPO) ligand.

10. The method of claim 9 , wherein light absorption from the ligand allows for at least a three order of magnitude increase in light absorption through the method, as opposed to using NaGd 1-x Eu x F 4 without the ligand.

11. A nanoparticle comprising:
a core, wherein the core comprises a first lanthanide and Yb; and
a shell coating the core, wherein the shell is doped with a second lanthanide and wherein the shell comprises 3,4,3-LI(1,2-HOPO), wherein the first lanthanide and the second lanthanide are a same lanthanide, wherein the nanoparticle comprises NaGd 1-x Eu x F 4 , wherein x is between 0 and 1, and wherein 3,4,3-LI(1,2-HOPO) is attached to a surface of the nanoparticle,
wherein the nanoparticle is configured to provide for at least a two order of magnitude increase in light absorption by NaGd 1-x Eu x F 4 as compared to light absorption by NaGd 1-x Eu x F 4 without 3,4,3-LI(1,2-HOPO).

12. The nanoparticle of claim 11 , wherein the nanoparticle displays Yb 3+ emission between 950 and 1060 nm upon illumination with UV light.

13. The nanoparticle of claim 11 , wherein the nanoparticle can generate two infrared photons for a single photon absorbed by 3,4,3-LI(1,2-HOPO).

14. The nanoparticle of claim 11 , wherein the first lanthanide and the second lanthanide is one or more of Pr 3+ , Nd 3+ or Tb 3+ .

15. The nanoparticle of claim 11 , wherein the shell is singly doped.

16. A method of producing two-photon emission, the method comprising:
providing a nanoparticle as claimed in claim 11 ;
irradiating the 3,4,3-LI(1,2-HOPO);
transferring energy from 3,4,3-LI(1,2-HOPO) to the second lanthanide;
transferring energy from the second lanthanide to the first lanthanide;
transferring energy from the first lanthanide to Yb, wherein the first lanthanide and the second lanthanide are a same lanthanide; and
emitting two photons from Yb a photon that excited 3,4,3-LI(1,2-HOPO).

17. The method of claim 16 , further comprising cooling the nanoparticle.

18. The method of claim 17 , wherein the nanoparticle has a temperature of about 77-350K.

Assignees

• Univ California

Inventors

• Agbo Peter
• Abergel Rebecca J

Classifications

• H10F77/45

  Wavelength conversion means, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements · CPC title

• C09K2211/182

  of the rare earth metals, i.e. Sc, Y or lanthanide · CPC title

• C09K2211/1022

  bridged by heteroatoms, e.g. N, P, Si or B · CPC title

• C09K2211/1029

  containing one nitrogen atom as the heteroatom · CPC title

• C09K11/7791

  with alkali or alkaline earth metals · CPC title