A water-based curable composition, for production of coatings having an antimicrobial property, contains at least one film-forming polymer, optionally at least one additive and/or at least one curing agent, and at least one up-conversion phosphor of the general formula (I): A.sub.1-x-y-zB*.sub.yB.sub.2SiO.sub.4:Ln.sup.1.sub.x,Ln.sup.2.sub.z. In the general formula (I), x=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 Mg, Ca, Sr and Ba; B is selected from Li, Na, K. Rb and Cs; B* is selected from Li, Na and K; and preferably B and B* are not the same. Additionally, Ln.sup.1 is selected from praseodymium (Pr), erbium (Er), and neodymium (Nd); and Ln.sup.2 is gadolinium (Gd). The phosphor, as a result of an aftertreatment, includes at least one material which has a band gap of greater than 6.0 electronvolts (eV) and is hydrolysis-stable.

A curable composition for production of coatings having an antimicrobial property, contains at least one film-forming polymer, optionally at least one additive and/or at least one curing agent, and at least one up-conversion phosphor of the general formula (I): A.sub.1-x-y-zB*.sub.yB.sub.2SiO.sub.4:Ln.sup.1.sub.x,Ln.sup.2.sub.z. In the general formula (I), x=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 Mg, Ca, Sr and Ba; B is selected from Li, Na, K, Rb and Cs; B* is selected from Li, Na and K; and preferably B and B* are not the same. Additionally, Ln.sup.1 is selected from praseodymium (Pr), erbium (Er), and neodymium (Nd); and Ln.sup.2 is gadolinium (Gd). The phosphor has been prepared using at least one halogen-containing flux.

A process can be used for the preparation of an up-conversion phosphor of the general formula (I):
A.sub.1-x-y-zB*.sub.yB.sub.2SiO.sub.4:Ln.sup.1.sub.x,Ln.sup.2.sub.z,(I).
The process involves preparing a mixture, introducing the mixture into a reaction chamber of a thermal apparatus, heating the mixture until a thermal treatment temperature is reached with a heating ramp, thermally treating the heated mixture for a holding time of at least 0.02 h, cooling the thermally treated material to room temperature while maintaining a cooling ramp, and obtaining a silicate-based lanthanoid ion-doped phosphor according to formula (I).

An oxide fluorescent material comprises: at least one first element M.sup.1 selected from Li, Na, K, Rb, and Cs; at least one second element M.sup.2 selected from Mg, Ca, Sr, Ba, and Zn; at least one third element M.sup.3 selected from B, Al, Ga, In, and rare earth elements; at least one fourth element M.sup.4 selected from Si, Ti, Ge, Zr, Sn, Hf, and Pb; O; and Cr, wherein when the molar ratio of the at least one fourth element M.sup.4 in 1 mol of the composition is 5, the molar ratio of the at least one first element M.sup.1 is 0.7 or more and 1.3 or less, the molar ratio of the at least one second element M.sup.2 is 1.5 or more and 2.5 or less, the molar ratio of the at least one third element M.sup.3 is 0.7 or more and 1.3 or less, the molar ratio of oxygen is 12.9 or more and 15.1 or less, and the molar ratio of Cr is more than 0 and 0.2 or less, and wherein the oxide fluorescent material has a light emission peak wavelength in a range of 700 nm or more and 1,050 nm or less in a light emission spectrum of the oxide fluorescent material.

A silicate-based lanthanide ion doped material converts electromagnetic radiation energy of a longer wavelength of below 530 nm to electromagnetic radiation energy of shorter wavelengths in the range of 220 to 425 nm. The silicate-based material is a crystalline silicate material doped with lanthanide ions selected from praseodymium, gadolinium, erbium, and neodymium. For co-doping, at least two of the lanthanide ions are used. The silicate-based material is obtainable from a blend comprising salts and an organic solvent, followed by specific calcination processes and tribological impacts to adjust particle size and to increase the crystallinity of the particles. The silicate-based material can be used to inactivate microorganisms or cells covering a surface containing the silicate-based material under exposure of electromagnetic radiation energy of a longer wavelength of below 500 nm.