PROCESS FOR THE PREPARATION OF FLUXED UP-CONVERSION PHOSPHORS

Abstract

A process can be used for the preparation of an up-conversion phosphor of the general formula (I)

Description

Claims

1. A process for the preparation of an up-conversion phosphor of the general formula (I) whereinx = 0.0001 - 0.0500;z = 0.0000 or z = 0.0001 to 0.3000 with the proviso that y = x + z;A is selected from the group consisting of Mg, Ca, Sr, and Ba;B is selected from the group consisting of Li, Na, K, Rb, and Cs;B* is selected from the group consisting of Li, Na, and K,Ln1 is selected from the group consisting of praseodymium (Pr), erbium (Er),and neodymium (Nd); andLn2 is gadolinium (Gd),

2. The process according to claim 1, wherein an amount of the at least one flux is not more than 50.0% by weight, based on the total amount of the reactants.

3. The process according to claim 1, wherein d) is conducted under air atmosphere.

4. The process according to claim 1, wherein the lanthanoid is praseodymium.

5. The process according to claim 1, wherein alkali metals are sodium and/or lithium.

6. The process according to claim 1, wherein an alkaline earth metal is calcium.

7. The process according to claim 1, wherein the silicate-based up-conversion phosphor of the general formula (I) is doped with praseodymium.

8. A silicate-based up-conversion phosphor of the general formula (I) whereinx = 0.0001 - 0.0500;z = 0.0000 or z = 0.0001 to 0.3000 with the proviso that y = x + z;A is selected from the group consisting of Mg, Ca, Sr, and Ba;B is selected from the group consisting of Li, Na, K, Rb, and Cs;B* is selected from the group consisting of Li, Na, and K;Ln1 is selected from the group consisting of praseodymium (Pr), erbium (Er), and neodymium (Nd);Ln2 is gadolinium (Gd),obtainable by the process according to claim 1, wherein the phosphor has a specific surface area determined by gas absorption according to Brunauer, Emmett and Teller (BET) of 1 to 500 m2/g, measured to ISO 9277, DIN 66131.

9. The phosphor according to claim 8, wherein the phosphor has been doped with praseodymium and co-doped with gadolinium.

10. The phosphor according to claim 8, wherein the phosphor is a solidified melt composed of crystalline silicates or of crystalline silicates doped with lanthanoid ions, comprising at least one alkali metal ion and at least one alkaline earth metal ion.

11. The phosphor according to claim 8, wherein the phosphor is at least partially crystalline.

12. The phosphor according to claim 8, wherein the phosphor is a compound of the general formula (Ia) whereinA is selected from the group consisting of Mg, Ca, Sr, and Ba;B is selected from the group consisting of Li, Na, K, Rb, and Cs;B* is selected from the group consisting of Li, Na, and K;x = 0.0001 - 0.0500; andz = 0.0000 or z = 0.0001 to 0.3000 with the proviso that: y = x + z.

13. The phosphor according to claim 8, wherein the phosphor is a compound of the general formula (II) whereinLn is selected from the group consisting of praseodymium, gadolinium, erbium, and neodymium;a = 0.0000 to 1.0000; andb = 0.0001 to 0.5000.

14. The phosphor according to claim 8, wherein the phosphor is a compound of the general formula (IIa) wherein b = 0.0001 to 1.

15. The phosphor according to claim 8, wherein the phosphor is .

16. The phosphor according to claim 13, wherein the compound according to formula (II) has XRPD signals in the range from 23° 2θ to 27° 2θ and from 34° 2θ to 39.5° 2θ.

17. A method for production of a coating having an antimicrobial property, the method comprising: applying a composition to a substrate,wherein the composition comprises the phosphor according to claim 8,at least one film-forming polymer,optionally, at least one additive, andoptionally, at least one curing agent.

18. The process according to claim 1, wherein the lanthanoid oxide is Pr6O11 and/or Gd2O3.

19. The process according to claim 1, wherein the at least one alkaline earth metal salt is calcium carbonate, and the at least one alkali metal salt is lithium carbonate and sodium carbonate.

20. The process according to claim 1, wherein the at least one flux is selected from the group consisting of ammonium chloride, sodium chloride, sodium fluoride, sodium bromide, lithium fluoride, lithium chloride, calcium chloride, calcium fluoride, praseodymium fluoride, and praseodymium chloride.