Blue to UV up-converter comprising lanthanide ions such as pr+activated and optionally gd+co-activated silicates and its production process and application for surface disinfection purposes

Abstract

A silicate-based lanthanide ion-doped material is disclosed for converting electromagnetic radiation energy with longer wavelengths below 530 nm into electromagnetic radiation energy with 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 ilium, thorium, erbium, and neodymium, and co-doping involves at least two of these ions. Furthermore, the silicate-based material is particularly derived from a mixture containing a salt and an organic solvent, followed by specific calcination and friction impact processes to adjust the particle size and 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 upon exposure to electromagnetic radiation energy with longer wavelengths below 500 nm.

Description

[Technical Field] A silicate-based lanthanide ion-doped material is disclosed for converting electromagnetic radiation energy with longer wavelengths below 530 nm into electromagnetic radiation energy with 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 ilium, thorium, erbium, and neodymium, with co-doping involving at least two of these ions. Furthermore, the silicate-based material is particularly derived from a dopant containing a salt and an organic solvent, followed by specific calcination and friction impact processes to adjust the particle size and increase the crystallinity of the particles. The silicate-based material can be used to inactivate microorganisms or cells upon exposure to electromagnetic radiation energy with longer wavelengths below 500 nm. [Previous Technology] Since the invention of effective blue light or UV-A emitting (In,Ga)N semiconductor materials (365 to 500 nm), inorganic solid-state light sources have outperformed other lighting technologies such as incandescent and discharge lamps. Therefore, both indoor and outdoor lighting primarily utilize phosphor-converted light-emitting diodes (pcLEDs) with (In,Ga)N as the primary radiation source. This trend is expected to continue for decades to come, with blue-emitting (In,Ga)N LEDs becoming the dominant light source across all types of lighting applications, including indoor, outdoor, advertising, architectural, decorative, custom, and street lighting. Indoor lighting will therefore rely on semiconductor light sources with emission bands between 400 and 480 nm, which will be partially converted by inorganic phosphors to produce white light. However, the target color temperature, accounting for approximately 5 to 10% of the total power distribution, will remain within the blue spectrum, meaning this radiation can force the upsampling converter of the lighting to achieve UV radiation at the illumination point. Recently, this opportunity has spurred a dedicated R&D project aimed at identifying effective blue-to-UV-C upscaling materials, such as Y₂SiO₅:Pr,Gd,Li, and others. A major problem with currently discovered and disclosed materials is their low upscaling efficiency, just above the detection level or signal-to-noise ratio. Furthermore, US 2013 / 0052079 discloses a composition containing phosphors that converts initial electromagnetic energy (A) into electromagnetic energy (B), thereby inactivating or killing microorganisms. However, the method described in that paper does not result in the phosphor exhibiting upscaling properties. What is truly needed is an upscaling material that can significantly reduce infectious microorganisms during typical sunlight exposure (i.e., within a few hours), thereby effectively achieving daily microbial reduction. In addition, the material must be environmentally friendly and exhibit a lifespan of at least 10,000 hours. Finally, the material must be cost-effective and recyclable to enable widespread integration into such surface coatings. Furthermore, the efficiency of upconversion materials must therefore be much better than known materials, since only the remaining 5 to 10% of the total power distribution in an LED remains in the blue spectrum and is used in upconversions for forced excitation lighting to obtain UV radiation at the illumination point. [Summary of the Invention] Therefore, the object of this invention is to provide an inorganic material for upscaling blue / green light to UV radiation with improved efficiency, and a method for preparing such a material. The object solves the problem through the disclosed novel inorganic silicate-based material for upscaling blue / green light to UV radiation, its preparation method, and its application in coatings, substrate surfaces, thin films, and composite layers. Particularly preferred embodiments are disclosed in the appended claims and specification. One preferred embodiment of the invention relates to a Pr3+ activated and Gd3+ co-doped silicate, which is based on the idealized general formula Al-xy-zB*yB2SiO4:Prx and optionally Gdz, particularly Al-xy-zB*yB2SiO4:Prx and optionally Gdz, wherein A = Mg, Ca, Sr, Ba; and B = Li, Na, K, Rb, Cs, preferably Li, Na, K, particularly preferably Li; and B* = Li, Na, K, Rb, Cs, preferably Na, K. In both equations, x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0 or z = 0.0001 to 0.3, preferably 0.001 to 0.3, and y = x + z, where y can be y = 0.0001 to 0.35, preferably i) y = x if z = 0, and ii) y = 0.0002 to 0.35 if z = 0.001 to 0.3, B*y is used for charge compensation of Prx and Gdz. Preferred examples are Ca0.98Pr0.01Na0.01Li2SiO4 or Ca0.96Pr0.01Gd0.01Na0.02Li2SiO4. Alternatively, the idealized general formula could be A1-2x-2zB*x+zB2SiO4:Prx,Gdz, where x + z in B* are coupled to Prx and Gdz. Another embodiment of the invention relates to incorporating such Vis and / or UV radiation upscaling converter materials into a polymer matrix. Silicate-based materials according to the invention, doped with lanthanides, can reduce the concentration of microorganisms on a surface under sunlight or LED illumination. The object of the invention is to provide a UV emitting material, particularly one capable of emitting electromagnetic radiation energy in the wavelength range of 220 to 425 nm, particularly 240 nm to 320 nm, preferably in the range of 250 to 320 nm. Ti and thorium co-doped silicates exhibit very strong emission at 311 nm (Figure 26). Another object of the invention is to provide a composition or film comprising at least one type of photoluminescent inorganic microscale particles for self-sterilization purposes. These particles can convert blue to green (380 to 550 nm) photons into UV photons, a process known as upsampling. In particular, these particles have a content greater than 70%, especially equal to or greater than 80% or 90%, more preferably equal to or greater than 95% or 98%.The optimal crystallinity is greater than or equal to 99%. Crystallinity can be assessed using Rietveld analysis, a method known to those skilled in the art (crystallography) (Madsen et al., Description and survey of methodologies for the determination of amorphous content via X-ray powder diffraction, Z. Kristallogr. 226 (2011) 944-955). According to the main embodiments of the present invention, UV-emitting materials, silicate-based lanthanide ion-doped materials, and especially materials capable of emitting electromagnetic radiation energy in the wavelength (shorter wavelength) range of 220 to 425 nm, particularly 240 nm to 320 nm, are harmless to microorganisms without irradiation, particularly without irradiation in the wavelength range of 450 nm and longer, particularly 450 nm to 530 nm. UV-emitting materials (silate-based lanthanide ion-doped materials) irradiated with wavelengths in the range of 450 nm and longer, particularly in the range of 450 nm to 530 nm, induce electromagnetic radiation energy with emission wavelengths (shorter wavelengths) in the range of 220 to 425 nm, particularly in the range of 240 nm to 320 nm, which is harmful to microorganisms. This invention utilizes a host silicate-based material doped with Pr3+ and randomly co-doped with Gd3+, wherein: - Blue light (wavelength below 500 nm) is absorbed through the transition from the ground state configuration [Xe]4f2 of Pr3+ to the excited state 3P0,1,2. The photon energy corresponds to photons with wavelengths in the range of 440 to 490 nm. - In a second step, after relaxation to the 3P0 energy level, excited state absorption, through the reuse of a blue pump source, induces the occurrence of the excited state configuration [Xe]4f15d1 population. This requires the crystal field component of the excited state configuration [Xe]4f15d1 to be located in the spectral range of 220 to 250 nm. Therefore, a suitable luminescent material must exhibit appropriate crystal field splitting to obtain and request an excited 5d state within this spectral range. - Upon excitation, the lowest crystal field component of the excited state configuration [Xe]4f15d1 returns upon emitting a photon to the ground state, thus generating UV radiation. The requested material, through Gd3+ co-doping, results in an energy transfer between Pr3+ and Gd3+, subsequently leading to a main emission at 311 nm. Currently,PCLEDs are the most efficient white light source and are therefore widely used in various conventional lighting applications. The best-implemented cool white PCLED wall socket efficiency is almost 60%, with radiant flux in the range of a few watts per PCLED. Since upsampling can produce an efficiency of about 25%, and indoor lighting requires at least 500 lm / m² or 5 W / m² (for a 100 lm / W light source), there is great interest in processes using the blue to green portion of the emission spectrum for so-called low-dose surface disinfection. According to the invention, upsampling refers to converting electromagnetic radiation energy of longer wavelengths, particularly below 500 nm, preferably in the range of 365 to 500 nm, and most preferably in the range of 440 to 490 nm, into electromagnetic radiation energy of shorter wavelengths, particularly in the range of 220 to 425 nm, and most preferably in the range of 250 to 325 nm. Therefore, the object of this invention is a silicate-based lanthanide ion-doped material for converting longer wavelength electromagnetic radiation energy into shorter wavelength electromagnetic radiation energy. The silicate-based material is a crystalline silicate material doped with lanthanide ions (preferably lanthanide ions (III+), selected from ilium, thorium, erbium, and neodymium; co-doped, at least two of these). Specifically, at least one longer wavelength electromagnetic radiation energy below 530 nm (preferably below 500 nm, for example 365 to 500 nm, particularly 440 to 495 nm, most preferably 440 to 490 nm) is converted into at least one shorter wavelength electromagnetic radiation energy in the range of 220 to 425 nm (particularly 250 to 350 nm, more preferably 250 to 320 nm). In particular, the crystalline silicate material is doped or co-doped with lanthanide ions, wherein the lanthanide ions are selected from lanthanide ions (III+). According to a preferred embodiment of the present invention, a silicate-based lanthanide ion-doped material is provided for converting longer wavelength electromagnetic radiation energy into shorter wavelength electromagnetic radiation energy. The silicate-based material is a crystalline silicate material doped with lanthanide ions (III+) selected from p-xylene (III+), yttrium (III+), erbium (III+), and neodymium (III+), and co-doping involves at least two of these ions (III+). According to a preferred embodiment of the present invention, the lanthanide ions are selected from p-xylene (III+) (Pr3+), yttrium (III+) (Gd3+), erbium (III+) (Er3+), and neodymium (III+) (Nd3+), and co-doping involves at least two of these ions. In a preferred embodiment, due to calcination in a reducing atmosphere, the silicate-based lanthanide ion-doped material is specifically free of lanthanide ions (IV+). Therefore, when the material according to the invention is irradiated with electromagnetic radiation energy of a longer wavelength below 530 nm (particularly 440 to 495 nm, preferably 440 to 490 nm), it emits at least a wavelength of 220 to 425 nm (particularly 250 to 350 nm).The electromagnetic radiation energy is preferably in the shorter wavelength range of 250 to 320 nm. According to Figures 11 and 12, the emission spectra of CaLi₂SiO₄:Pr,Na(1 mol-%) (also known as (Ca₀.98Pr₀.01Na₀.01)Li₂SiO₄ and CaLi₂SiO₄:Pr,Gd(1 mol-%),Na(2 mol-%) (also known as (Ca₀.96Pr₀.01Gd₀.01Na₀.02)Li₂SiO₄) clearly show an emission spectrum in the range of 275 to 375 nm, with an intensity of at least 1 x 10⁵ counts / (mm²*s) (excitation laser: 445 nm, 75 mW). Excitation with a 488 nm laser at an efficiency of 150 mW, as shown in Figures 11 and 12, yielded CaLi₂SiO₄:Pr,Na(1 mol-%). The emission spectra of (also known as (Ca0.98Pr0.01Na0.01)Li2SiO4) and CaLi2SiO4:Pr,Gd(1mol-%),Na(2mol-%) (also known as (Ca0.96Pr0.01Gd0.01Na0.02)Li2SiO4) clearly exhibit emission spectral intensities in the range of 225 to 425 nm, with a maximum intensity of at least 1 x 10⁵ counts / (mm²*s), particularly in the sub-range of 230 to 325 nm and optionally in the sub-range of 365 to 425 nm. A particularly preferred maximum intensity is in the range of 275 to 320 nm, particularly with an intensity of at least 2 x 10⁵ counts / (mm²*s), more preferably 2.5 x 10⁵ counts / (mm²*s). [The text then abruptly shifts to a different topic:] ...at 488 nm with an efficiency of 150 mW or at 445 nm, 75... Laser excitation at mW (see Figure 12) yielded an emission spectrum of CaLi₂SiO₄:Pr,Gd(1 mol-%),Na(2 mol-%) (also known as (Ca0.96Pr0.01Gd0.01Na0.02)Li₂SiO₄) with a significant additional emission intensity in the 300-320 nm range (particularly 312 nm), with a maximum intensity of at least 5 x 10⁵ counts / (mm²*s), particularly at least 6 x 10⁵ counts / (mm²*s), and more preferably at least 7 x 10⁵ counts / (mm²*s). The strong emission at approximately 312 nm is caused by Gd. The intensity of the emitted electromagnetic spectrum in the 220-425 nm range is at least 5 x 10⁴ counts / (mm²*s), more preferably at least 1 x 10⁵ counts / (mm²*s).More preferably, the intensity of the emitted electromagnetic spectrum is at least 2 x 10⁵ counts / (mm²*s). Specifically, the intensity of the emitted electromagnetic spectrum is at least 2 x 10⁵ counts / (mm²*s) in the 220 to 330 nm range and at least 2 x 10⁵ counts / (mm²*s) in the 220 to 425 nm range. The emission spectrum is emitted by a laser, particularly a laser with an efficiency of 75 mW at 445 nm and / or 150 mW at 488 nm. The preferred maximum value of the converted electromagnetic radiation energy is in the 250 to 350 nm range, particularly in the 270 to 330 nm range, and more preferably in the 280 to 330 nm range. Preferably, the silicate-based material is doped with argon and co-doped with thiogen. Specifically, crystalline silicate materials are doped with argon and co-doped with thiogen. According to one aspect of the present invention, a silicate-based material is preferred, wherein the lanthanide-doped crystalline silicate material is selected from cyclic silicates (e.g., [Si3O9]6-, [Si4O12]8- and / or [Si6O18]12-), pyrosilicons (such as [Si2O7]6-), and inorganic silicates (so-called chain silicates) having a single-chain atomic ratio of Si:O 1:3 and a double-chain atomic ratio of Si:O 4:11. A preferred object of the present invention is a silicate-based lanthanide-doped material for converting longer wavelength electromagnetic radiation energy into shorter wavelength electromagnetic radiation energy, wherein the silicate-based material is a crystalline silicate material doped with lanthanide ions (III+) (Ln3+), particularly obtainable by heating, preferably by calcining the silicate-based lanthanide-doped material in a reducing atmosphere. In particular, heating to above 600°C but below the melting point, preferably 50°C to 200°C below the melting point, is performed in a reducing atmosphere. The reduction step following calcination in air is particularly correlated with increasing the amount of lanthanide ions (III+), thus increasing the intensity of the material's upscaling. According to a preferred embodiment, the crystalline silicate material is doped or co-doped with lanthanide ions, wherein these lanthanide ions are selected from lanthanide ions (III+). According to one aspect of the invention, it is preferably a silicate-based material, wherein the lanthanide-doped crystalline silicate material is selected from silicates that are anhydrous and have -OH functionality as crystalline solvates. In particular, lanthanide-doped crystalline silicate materials (preferably Ln3+, preferably more than 95% Ln3+ and less than 5% Ln4+) are selected from silicates that do not contain stoichiometric hydrates and / or solvates. Particularly preferred are silicate-based materials, wherein i) crystalline silicate materials are not silicate hydrates, and in particular, silicates do not contain water of crystallization. Anhydrous silicates are also preferred. Adsorbed water or water on the surface of silicate-based materials is not considered silicate hydrate or water generated during crystallization. However,The silicate-based material is preferably free of adsorbed water and water on the particle surface. In particular, it is more preferably that the crystallinity of the silicate-based material (especially particles with the particle size distribution disclosed above) is greater than 70%, and more preferably greater than or equal to 80%, 85%, 90%, 95%, and most preferably greater than or equal to 98%, 99%, 99.5%, 99.8% (particle size can be determined by analysis, for example, through long-term XRPD and the peak half-width of the Debye-Scherrer equation; the strongest reflection height can also be used by XRPD with Rietveld refinement). In addition, silicate-based materials are particularly free of amorphous phases. The absence of amorphous phases in silicate-based materials means less than 5%, preferably less than 2%, and most preferably less than 1%, 0.01%, 0.001%, and 0.0001% (see the analysis above, using the Rietveld-refinement algorithm of XRPD). More preferably, it is a silicate-based material, wherein the silicate-based material is a crystalline silicate material, comprising i) a crystalline pure phase, particularly a crystalline material comprising a crystalline phase, particularly a single crystalline phase, the crystalline phase covering 90 wt% of the crystalline material (100 wt%), particularly the crystalline phase covering greater than or equal to 95 wt% of the crystalline material, more preferably greater than or equal to 98 wt%, most preferably 99 wt%, 99.5 wt%, or 99.8 wt% of the crystalline material, or ii) a silica-based material, comprising at least one crystalline phase, particularly a crystalline phase covering at least 90 wt% of the silica-based material (100 wt%), particularly the crystalline phase covering greater than or equal to 95 wt% of the silica-based material, more preferably the crystalline phase covering greater than or equal to 98 wt%, 99 wt%, 99.5 wt%, 99.8 wt%, or 99.9 wt% of the silica-based material. The preferred crystalline silicate-based material is a pure crystalline phase (e.g., free from different crystalline or amorphous phases). According to another aspect of the invention, the crystalline silicate material is preferably a solid solution of a crystalline silicate doped with a lanthanide ion comprising at least one alkali metal ion and at least one alkaline earth metal ion, particularly a silicate doped with tungsten and optionally co-doped with thionium. Particularly preferred is a crystalline silicate doped with a lanthanide ion selected from tungsten and optionally thionium, comprising at least one alkali metal ion selected from Li, Na, K, Rb, Cs, preferably selected from Li and optionally Na or K, more preferably selected from Li and optionally Na, and comprising at least one alkaline earth metal ion selected from Mg, Ca, Sr, Ba, preferably selected from Ca. The preferred crystalline silicate is one with a crystallinity equal to or greater than 90%, preferably equal to or greater than 95%, and an average particle size D50 in the range of 1 micrometer to 20 micrometers.Preferably, the size is in the range of 5 to 15 micrometers. The preferred crystalline silicate material doped with lanthanide ions and containing at least one alkali metal ion and at least one alkaline earth metal ion is selected from anhydrous or water-free silicates, such as silicates containing crystal water, which are selected from the crystal water of cyclic silicates ([Si3O9]6-, [Si4O12]8-, [Si6O18]12-), pyrosilicates ([Si2O7]6-), and inorganic silicates (chain silicates, Si:O 1:3 (single chain), Si:O 4:11 double chain). One particularly preferred embodiment of the present invention is a silicate-based material or a silicate-based material, wherein the crystalline silicate material is selected from the idealized general formula I [Figure], wherein x = 0.0001 to 0.05, z = 0 or z = 0.0001 to 0.3 and y = x + z, wherein A is selected from Mg, Ca, Sr and Ba, wherein B is selected from Li, Na, K, Rb and Cs, wherein B* is selected from Li, Na and K, wherein B is equal to B* or B is not equal to B*, preferably B and B* are not equal, and Ln1 is selected from Pr, Erbium and Neodymium, optionally Ln2 is selected from Gd. The preferred crystal silicate is the one of Formula I above, wherein the crystallinity is equal to or greater than 90%, more preferably equal to or greater than 95%, and wherein the average particle size D50 is in the range of 1 micrometer to 20 micrometers, more preferably in the range of 5 to 15 micrometers. Another preferred embodiment of the present invention is a silicate-based material or a silicate-based material, wherein the crystalline silicate material is selected from the idealized general formula Ia [Figure] where A = Mg, Ca, Sr, Ba and B = Li, Na, K, Rb, Cs, and wherein in formula Ia x = 0.0001 to 0.05, z = 0 or z = 0.0001 to 0.3 and y = x + z, wherein B* is selected from Li, Na and K, which exists for the charge balance of silicate, wherein B is equal to B* or B is not equal to B*, preferably B and B* are not equal, preferably a silicate-based material, wherein the crystalline silicate material is selected from the idealized general formula II [Figure] where a = 0.0001 to 1, preferably 0.0001 to 0.1 and b = 0.0001 to 1, preferably 0.0001 to 0.1, or a = 0 or 0.0001 to 0.1, preferably a = 0 and b = 0.0001 to 0.35, preferably b = 0.001 to 0.1, and Ln = lanthanide ions selected from ilium, thorium, erbium, and neodymium, with co-doping involving at least two of them.In particular, ferroxene and optionally droxylin and thiocyanate are preferred. According to the present invention, preferred silicate-based lanthanide ion-doped materials are A0.9998-0.9B*0.0001-0.05B2SiO4:Pr0.0001-0.05 and A0.9998-0.30B*0.0001-0.35B2SiO4:Pr0.0001-0.05Gd0.0001-0.30, wherein the A series is selected from Mg, Ca, Sr, Ba, and the B series is selected from Li, Na, K, Rb, Cs, preferably Li, Na, K, more preferably Li, and the B* series is selected from Na and K. Particularly preferred are Ca0.98Pr0.01Na0.01Li2SiO4, Ca0.96Pr0.01Gd0.01Na0.02Li2SiO4, Sr0.98Pr0.01Na0.01Li2SiO4, and Sr0.96Pr0.01Gd0.01Na0.02Li2SiO4. For example, in the silicate-based crystalline materials of the present invention, using strontium as the alkaline earth metal ion, SrLi2SiO4:Pr3+ exhibits emission from 254 to 375 nm, particularly with a maximum value of 320 nm, and SrLi2SiO4:Pr3+,Gd3+ exhibits emission from 254 to 375 nm, particularly with a maximum value of 312 nm. In particular, the crystalline silicate materials contain at least two different alkali metal ions. More preferably, the crystalline silicate materials contain at least one alkaline earth metal ion and at least two different alkali metal ions. According to one embodiment of the silicate-based material of the present invention, the crystalline silicate material of Formula II has an XRPD signal, particularly a high-intensity signal, ranging from 23˚ 2Θ to 27˚ 2Θ and 34˚ 2Θ to 39.5˚ 2Θ, particularly from 24.4˚ 2Θ to 25.4˚ 2Θ and 36.8˚ 2Θ to 37.8˚ 2Θ, wherein, in particular, the signal is measured using Cu-Kα radiation according to Bragg-Brentano geometry. Furthermore, the subject of the present invention is a silicate-based crystalline material, doped with argon and optionally co-doped with thionium, selected from the following list. Surprisingly, these materials exhibited fairly efficient blue-to-UV radiation upsampling conversion: Mg1-xy-zPrxGdzB*yLi2SiO4 (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Ca1-xy-zPrxGdzB*yLi2SiO4 (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Sr1-xy-zPrxGdzB*yLi2SiO4 (x = 0.0001 to 0.05, preferably 0.001 to 0.05, ...z = 0) and optionally Gd (z = 0.0001 to 0.3) Ba1-xy-zPrxGdzB*yLi2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Mg1-xy-zPrxGdzB*yNa2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Ca1-xy-zPrxGdzB*yNa2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) 0) and optionally Gd (z = 0.0001 to 0.3) Sr1-xy-zPrxGdzB*yNa2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Ba1-xy-zPrxGdzB*yNa2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Mg1-xy-zPrxGdzB*yK2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) 0) and optionally Gd (z = 0.0001 to 0.3) Ca1-xy-zPrxGdzB*yK2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Sr1-xy-zPrxGdzB*yK2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Ba1-xy-zPrxGdzB*yK2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Mg1-xy-zPrxGdzB*yRb2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and optionally Gd (z = 0.0001 to 0.3) Ca1-xy-zPrxGdzB*yRb2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05,The formulas are: Sr1-xy-zPrxGdzB*yRb2SiO4:Pr (x = 0.0001 to 0.05, preferably 0.001 to 0.05, z = 0) and Ba ... The particle size of the silica-based crystalline material is preferably in the range of 1 micrometer to 100 micrometers (μm), more preferably in the range of 1 micrometer to 50 micrometers (μm), and even more preferably in the range of 1 micrometer to 20 micrometers (μm). More preferably, the average particle size (D50) of the silica-based crystalline material is in the range of 1 micrometer to 100 micrometers (μm), more preferably in the range of 1 micrometer to 50 micrometers (μm), and even more preferably in the range of 1 micrometer to 20 micrometers (μm). More preferably, the average particle size (D50) of the silica-based crystalline material is in the range of 2 micrometers to 20 micrometers (μm), more preferably in the range of 5 micrometers to 20 micrometers (μm), and even more preferably in the range of 5 micrometers to 15 micrometers (μm), particularly about 10 micrometers and - / + 5 micrometers. According to a particular preferred embodiment, the particle size distribution is D10 of 2 to 7 micrometers, D50 of 5 to 15 micrometers, and D90 of less than 20 micrometers, preferably less than 18 micrometers. The particle size distribution was determined using a Horiba LA-950-V2 organic particle size analyzer with dynamic laser light scattering. All silicate-based crystalline materials of the present invention contain at least a trivalent activator, Pr3+, whose ground state configuration [Xe]4f2 carries the 13SLJ energy level, which is below the lowest crystal field component of the excited state configuration [Xe]4f15d1. By appropriately selecting the host material, the lowest crystal field component of the excited state configuration of Pr3+ can be adjusted to be higher than the ground state energy level 3H4, which belongs to the ground state configuration, by 35,000 to 40,000 cm-1. In this way, a two-photon absorption process can be performed at a single ion, which incidentally leads to the emission of UV photons. In particular, the Pr3+-doped silicate-based material used in accordance with and practiced according to the present invention is a blue light to UV radiation upscaling converter material that is more efficient than those materials currently disclosed in patents and peer-reviewed literature. According to another aspect of the present invention, the silicate-based lanthanide-doped material is requested to have a crystal field component of the excited-state configuration [Xe]4f15d1 in the spectral range of 220 to 250 nm. According to another aspect of the present invention,The silicate-based lanthanide-doped materials are requested to have a crystal field component of the excited-state configuration [Xe]4f15d1 with an emission spectrum ranging from 250 to 320 nm. Particularly preferred silicate-based materials are those in which electromagnetic radiation energy of longer wavelengths below 500 nm, particularly from below 490 nm to 450 nm, is converted into electromagnetic radiation energy of shorter wavelengths in the range of 230 nm to 380 nm. Specifically, the maximum emission intensity of the shorter wavelength electromagnetic radiation energy, particularly at least one maximum value or two maximum values ​​of the emitted shorter wavelengths, independently has an intensity of at least 1.103 counts / (mm²*s), particularly greater than 1.104 counts / (mm²*s), preferably greater than 1.105 counts / (mm²*s), and most preferably greater than 2.105 counts / (mm²*s). According to a preferred embodiment of the invention, the maximum intensity of the two maximum values ​​in the shorter wavelength range of 230 nm to 275 nm is 1.103 counts / (mm²*s), and the maximum intensity of the second maximum value in the range of 275 nm to 380 nm is at least greater than 1.104 counts / (mm²*s), more preferably greater than 1.105 counts / (mm²*s), and most preferably greater than 2.105 counts / (mm²*s). Specifically, the 445 nm 75 mW or 488 nm 150 mW lasers are used. For increased emission, a specific particle size is preferred. Therefore, the disclosed material is required to be micron-sized, submicron-sized to nano-sized particles in the range of 10 nm to 100 µm. The object of this invention is also a method for preparing silica-based materials and crystalline silicate-based materials obtainable by this method, the method comprising the following steps: - i) providing at least one lanthanide salt, particularly selected from lanthanide nitrates, lanthanide carbonates, lanthanide carboxylates, particularly lanthanide acetates, lanthanide sulfates, lanthanide oxides, particularly Pr6O11 and / or Gd2O3, wherein the lanthanide ion in the lanthanide oxide or lanthanide salt is selected from tungsten, thorium, erbium, neodymium, and co-doped with at least two of them; - ii) providing silicates, particularly silicate salts, more particularly alkali metal salts of silicates; - iii) providing at least one alkaline earth metal salt and at least one alkali metal salt selected from lithium salts or any lithium compound and optionally from sodium and potassium salts, particularly alkali metal silicates, preferably lithium salts selected from ii) and being lithium silicate; - a) grinding i), ii) and iii) The mixture is obtained by blending, or - b) blending i), ii) and iii) in an organic polar or nonpolar solvent of an aprotic solvent to obtain a mixture, wherein the obtained mixture b) is calcined at 600°C to 1000°C (step 1a) to remove organic components, particularly calcined at 600°C to 1000°C for at least 1 hour, particularly for more than or equal to 2 hours, under a normal atmosphere (air), to obtain a calcined mixture.- In the calcination step, the mixture a) or mixture b) is calcined, particularly in air, at a temperature below the melting temperature of the silica-based material, wherein at least partial crystallization occurs, particularly in the further calcination step (step 1b) at a temperature of 50 to 200°C for at least 3 hours, preferably in air, below the melting temperature of the silica-based material to allow the silicate-based material to crystallize, preferably at a temperature of 800 to 900°C, more preferably about 850°C, and crystallization occurs for at least 3 hours, particularly at least 12 hours, preferably in air. - In the further calcination step, at a rising temperature, particularly above 800°C and 50 to 200°C below the melting point of the material (step 2), for example at 850°C for at least 3 hours, more preferably at least 6 hours, lanthanum is reduced to Ln3+ ions in a reducing atmosphere. - A silicate-based lanthanide ion-doped material is obtained, particularly after the material has cooled. The reducing atmosphere may be a forming gas such as N2 or a mixture of argon and H2. The alternative reducing atmosphere may contain an inert gas, such as CO or NH3, as a reducing component. Cooling of the material is preferably performed at a rate of 100°C / h to 300°C / h (preferably 200°C / h to 300°C / h). The heating and cooling rates in calcination steps 1a and / or 1b are each independent at 100°C / h to 300°C / h, preferably 300°C / h. The heating and cooling rates in calcination step 2 are performed at 100°C / h to 300°C / h, preferably 200°C / h. A linear cooling rate is particularly preferred. In a preferred embodiment of the invention, the obtained silicate-based lanthanide ion-doped material is milled, particularly when the material is not subjected to tribological impact, such that the amount of tribological impact is sufficient to increase the crystallinity of the material, especially the crystallinity of the main crystalline phase of the silicate-based material. Specifically, the amorphous phase is reduced and the crystalline secondary phase is converted into the main crystalline phase. Preferably, the intensity of the primary reflection of the silicate-based lanthanide ion-doped material increases by at least 5%, particularly 10%, and more preferably at least 20%. For silicates of Formula II, the intensity of the primary reflection increases by at least 5%, and more preferably at least 10%, in the range of 34˚ 2Θ to 39.5˚ 2Θ. Another embodiment of the invention is a method in which the obtained silicate-based material is subjected to frictional impact at 200 rpm for 1 to 6 hours, preferably about 4 hours, using it as a grinding material. Grinding is carried out in a planetary ball mill (PM 200, Retsch) with a g-force up to 37.1 g, cup / bottle: corundum and grinding balls (Al2O3), 50 ml (9 balls, about 4.5 g of sample) or 125 ml (24 balls, about 20 g of sample). The grinding cup / bottle is eccentrically placed on the sun wheel of the planetary ball mill. The sun gear moves in the opposite direction to the grinding jar.The ratio is 1:-2. The grinding balls in the grinding cup / bottle are subjected to superimposed rotational motion, the so-called Coriolis force. The velocity difference between the balls and the bottle creates an interaction between friction and impact forces, thereby releasing high kinetic energy. Preferably, the intensity of the primary reflection of the obtained silicate-based lanthanide ion-doped material can be increased by at least 25%, particularly 30%, more preferably at least 40%, 50%, 60%, 70%, or 80% through the grinding step. For silicates of Formula II, the intensity of the primary reflection is increased by at least 50%, more preferably at least 60%, in the range of 34˚ 2Θ to 39.5˚ 2Θ. Preferably, this grinding step is the first grinding step, in which the particle size is reduced and undesirable phases in the solid are reduced. The object of this invention is also a silicate-based lanthanide ion-doped material for converting longer wavelength electromagnetic radiation energy into shorter wavelength electromagnetic radiation energy. It is obtained according to the method of this invention, wherein: the silicate-based material is a crystalline silicate material doped with lanthanide ions selected from ilium, thorium, erbium, and neodymium; co-doping involves at least two of these lanthanide ions; and wherein the lanthanide-doped crystalline silicate-based material is a solid solution of a crystalline silicate containing at least one alkali metal ion, preferably at least two different alkali metal ions, and at least one alkaline earth metal ion; and wherein the crystallinity of the silicate-based material is greater than 80%, particularly greater than or equal to 80%, greater than or equal to 85%, 90%, 95%, greater than or equal to 98%, 99%, 99.5%, 99.8%, wherein at least one is below 530 nm, particularly 490 to 450 nm. Electromagnetic radiation energy of longer wavelengths in the nm range is converted into electromagnetic radiation energy of shorter wavelengths in the 220 to 400 nm range, particularly in the 250 to 320 nm range. The longer wavelength, by definition, is always longer than the shorter wavelength. According to another embodiment, a composition, foil, or film system comprising the disclosed silicate-based material is used for self-disinfection purposes or for reducing microorganisms. The composition may contain any excipients, wherein the composition does not contain more than 1 to 15 wt% (particularly more than 10 wt%) of water or protonated solvents. The subject of this invention is also the use of silicate-based lanthanide ion-doped materials for UV sterilization or disinfection applications, particularly for indoor UV sterilization applications utilizing electromagnetic radiation energy from LEDs, especially pcLEDs, comprising a radiation maximum in the 450 to 480 nm range (in exposure to electromagnetic radiation energy of longer wavelengths below 500 nm, particularly the 450 to 480 nm range).

Implementation Method

Claims

1. A silicate-based lanthanide ion-doped material for converting longer wavelength electromagnetic radiation energy into shorter wavelength electromagnetic radiation energy, wherein the silicate-based material is a crystalline silicate material doped with tungsten and co-doped with thionium, comprising i) a pure crystalline phase, the crystalline material comprising a crystalline phase covering 90 wt% of the crystalline material (100 wt%), or ii) a silica-based material comprising at least one crystalline phase covering at least 90 wt% of the silica-based material (100 wt%), and wherein at least one longer wavelength electromagnetic radiation energy below 530 nm is converted into at least one shorter wavelength electromagnetic radiation energy in the range of 220 to 425 nm, wherein the maximum emission intensity of the shorter wavelength electromagnetic radiation energy is at least 1.103 counts / (mm²*s); wherein the crystalline silicate material is selected from the general formula I Al-xy-zB*yB2SiO4: Ln1x, Ln2z, I, where x = 0.0001 to 0.05, z = 0 or z = 0.0001 to 0.3 and y = x + z, where A is selected from Mg, Ca, Sr and Ba, where B is selected from Li, Na, K, Rb and Cs, where B* is selected from Li, Na and K, where B is equal to B* or B is not equal to B*, and Ln1 is ferroxene (Pr) and Ln2 is ferroxene (Gd).

2. The silicate-based lanthanide ion-doped material of claim 1, wherein i) the crystalline silicate material is not a silicate hydrate and the silicate does not contain water of crystallization.

3. The silicate-based lanthanide ion-doped material as described in claim 1, wherein the crystallinity of the material is greater than 70%.

4. A silicate-based lanthanide ion-doped material as claimed in any of claims 1 to 3, wherein the crystalline silicate material is a solid solution of a crystalline silicate or a crystalline silicate doped with lanthanide ions containing at least one alkali metal ion and at least one alkaline earth metal ion.

5. A silicate-based lanthanide ion-doped material as claimed in any of claims 1 to 3, wherein electromagnetic radiation energy of longer wavelengths below 500 nm is converted into electromagnetic radiation energy of shorter wavelengths in the range of 230 nm to 380 nm, wherein the maximum emission intensity of the electromagnetic radiation energy of the shorter wavelengths is at least 1.103 counts / (mm2*s).

6. A method for preparing a silicate-based lanthanide ion-doped material as claimed in any one of claims 1 to 5, comprising the following steps: - i) providing at least one lanthanide salt selected from lanthanide nitrates, lanthanide carbonates, lanthanide carboxylates, lanthanide acetates, lanthanide sulfates, and / or lanthanide oxides, wherein the lanthanide ion in the lanthanide oxide and / or lanthanide salt is selected from tungsten and thorium; - ii) providing a silicate; - iii) providing at least one alkaline earth metal salt and at least one alkali metal salt selected from lithium salts or any lithium compound and selected from sodium and potassium salts; - a) combining i), ii) and iii) by milling to obtain a mixture, or - b) In an organic polar or nonpolar solvent of a protic solvent, i), ii) and iii) are combined to obtain a mixture, wherein the mixture b) is calcined at 600°C to 1000°C to remove organic components, calcined at 600°C to 1000°C for at least 1 hour under normal atmosphere, and a calcined mixture is obtained; - In the calcination step, the mixture a) or the calcined mixture b) is calcined at a temperature below the melting temperature of the silica-based material, wherein at least partial crystallization occurs; and - In a further calcination step under a reducing atmosphere, lanthanum is reduced to Ln3+ ions, - a silicate-based lanthanide ion-doped material is obtained, wherein the silicate-based lanthanide ion-doped material is ground, wherein the silicate-based lanthanide ion-doped material is obtained by using corundum as the grinding material and subjected to friction impact at 100 to 500 rpm for 1 to 6 hours.

7. A silicate-based lanthanide ion-doped material obtainable by the method of claim 6, for converting longer wavelength electromagnetic radiation energy into shorter wavelength electromagnetic radiation energy, wherein: - the silicate-based material is a crystalline silicate material doped with lanthanide ions and co-doped with thorium, and wherein the lanthanide-doped crystalline silicate-based material is a crystalline silicate or a solid solution of a crystalline silicate containing at least one alkali metal ion and at least one alkaline earth metal ion, and wherein the crystallinity of the silicate-based material is greater than 80%, and wherein at least one longer wavelength electromagnetic radiation energy below 530 nm is converted into at least one shorter wavelength electromagnetic radiation energy in the range of 220 to 400 nm.

8. A composition, foil, or film comprising a silicate-based lanthanide ion-doped material as claimed in any one of claims 1 to 5 and 7, for self-disinfection purposes or for reducing microorganisms.

9. Use of a silicate-based lanthanide ion-doped material as claimed in any one of claims 1 to 5 and 7 for a UV sterilization application, for an indoor UV sterilization application utilizing electromagnetic radiation energy from an LED, comprising an emission maximum in the range of 450 to 480 nm, as an additive in a surface coating or as an additive in a material to provide a surface or coating of a material capable of inactivating microorganisms covering the surface or coating when exposed to electromagnetic radiation energy of a longer wavelength below 500 nm at an emission maximum in the range of 450 to 480 nm.

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