Microjet reactor based synthesis of nanophosphors

The method of any of the preceding claims, wherein the second mixture has a pH of more than 7, and/or wherein said precipitating agent is a base, preferably wherein the precipitating agent is urea or ammonium hydrogen carbonate.

The method of any of the preceding claims, wherein the contacting step is performed at a temperature of 50° C. or lower, preferably at room temperature or a temperature of 15°° C. to 30° C., and/or at a pressure of 5 bar or lower, preferably at a pressure of 0.5 bar to 5 bar.

The method of any of the preceding claims, wherein the nanoparticles are of the type Y2O3:Ln, Sc2O3:Ln, Lu2O3:Ln, and/or Gd2O3:Ln, and preferably:

• the pH of the second mixture is more than 8, and/or
• the pH of the third mixture is between 7.5 and 11, more preferably between 8 and 10.

The method of any of the preceding claims, wherein the microjet reactor has a nozzle size of between 200 and 300 μm, and/or wherein the first mixture and the second mixture are separately fed into the microjet reactor, preferably wherein the first mixture and the second mixture are fed into the microjet reactor at a pump pressure of about 50 bar.

The method of any of the preceding claims, wherein said heating comprises:

• heating particles having a D50 value of ≥1 nm, more preferably ≥2 nm, and a D50 value of ≤100 nm, more preferably and ≤20 nm,
• heating the nanoparticles at a temperature of 200°° C. or more;
• preferably at least 500° C., such as between 200 and 1500° C. or 500 and 1600° C., preferably between 300 and 1200° C., or between 500 and 1300° C., preferably for a period of at least 30 seconds, more preferably at least 1 minutes, more preferably from 1.5 minutes to 3 hours.

Nanoparticles obtainable by the method of any of the preceding claims, preferably wherein:

• the Ln comprises an ion chosen from the group of Tb3+, Eu3+ and Ce3+, and/or
• the nanoparticles comprise active ions disposed in a host lattice, wherein the host lattice is more preferably chosen from the group of garnets and metal oxides, even more preferably wherein the host lattice is of the type A13A25O12, wherein A1 is one or more selected from the group of yttrium, lutetium, and gadolinium;
• A2 is one or more selected from the group of aluminium, gallium, and scandium and/or wherein the host lattice is chosen from Y3Al5O12, Lu3Al5O12 or Y2O3.