Method for producing nanoparticles
Some embodiments disclosed herein are related to methods of preparing a nanoparticle composition comprising: providing an aerosol comprising a plurality of droplets of a precursor solution comprising at least one nanoparticle precursor and an expansive component; passing the aerosol through a plasma; and collecting a nanoparticle composition product from the carrier gas which has exited the plasma. Some embodiments relate to nanoparticle compositions provided by this process. Some embodiments relate to light-emitting diodes or light emitting devices comprising these compositions.
1. A method of preparing a nanoparticle composition comprising:
providing an aerosol comprising a plurality of droplets of a precursor solution and a carrier gas, wherein the precursor solution comprises at least one nanoparticle precursor, an expansive component, and a solvent;
passing the aerosol through a plasma; and
collecting a nanoparticle composition product from the carrier gas which has exited the plasma without quenching, wherein 95% of the nanoparticles by number in the nanoparticle composition have a diameter in the range of about 10 nm to about 100 nm.
2. The method of claim 1 , wherein the nanoparticle precursor comprises a metal nitrate.
3. The method of claim 1 , wherein the nanoparticle precursor comprises a nitrate of ytrrium, a nitrate of aluminum, and a nitrate of cerium.
4. The method of claim 1 , wherein the solvent comprises water.
5. The method of claim 1 , wherein the expansive component is a solid that decomposes to produce a gas upon heating.
6. The method of claim 1 , wherein the expansive component comprises at least one of urea, carbohydrazide, and glycine.
7. The method of claim 1 , wherein about 95% of the plurality of droplets by number have a diameter in the range of about 20 nm to about 200 μm.
8. The method of claim 1 , wherein the plasma is an RF thermal plasma.
9. The method of claim 1 , wherein the plasma is a DC thermal plasma.
10. The method of claim 1 , wherein the specific surface area of the nanoparticle composition is in the range of about 5 m 2 /g to about 200 m 2 /g.
11. The method of claim 1 , further comprising an annealing step.
12. A nanoparticle composition prepared by a method according to claim 1 .
13. The nanoparticle composition of claim 12 , comprising a yttrium aluminum garnet.
14. The nanoparticle composition of claim 12 , comprising a cerium-doped yttrium aluminum garnet.
15. A light-emitting device comprising:
a light-emitting diode, and
a phosphor comprising the nanoparticle composition of claim 12 , wherein the phosphor is positioned to receive and convert at least a portion of the light emitted from the light-emitting diode to light of a longer wavelength.
16. The method of claim 1 , wherein at least a portion of a reaction field of the plasma has a temperature of at least about 10,000° C.
17. The method of claim 1 , wherein the carrier gas is an inert gas.
18. The method of claim 1 , wherein no quench gas is applied to a flow exiting the plasma.