There is provided a paint including a pigment, a carrier liquid, a binder, one or more additives, and a taggant corresponding to the one or more additives. The taggant is provided in an amount up to substantially 0.1% by weight of the paint. The taggant is excitable by infra-red or UV light at one wavelength to emit light at one or more other wavelengths, the emission wavelength or spectrum of the taggant being indicative of the additive(s) in the paint. A method of authenticating the paint on a substrate is also provided.

Provided herein are phosphors of the general molecular formula:
A.sub.3-2xEu.sub.xMP.sub.3O.sub.9N,
wherein the variables are as defined herein. Methods of producing the phosphors are also provided. In some aspects, the present disclosure provides light-emitting devices comprising these phosphors.

The invention provides Y.sub.2O.sub.3:RE nanoparticles having a cubic crystal structure, wherein RE is a trivalent rare earth metal ion. The invention further provides a method of preparing Y.sub.2O.sub.3:RE nanoparticles, comprising: a) providing a mixture comprising (i) an yttrium salt and/or yttrium alkoxide, (ii) a rare earth metal salt and/or rare earth metal alkoxide, and (iii) an organic solvent; b) optionally, subjecting the mixture to a pre-treatment step which comprises heating the mixture at a temperature of at least 80° C. and/or at a temperature such that crystal water and/or organic impurities are removed, c) heating the mixture at a temperature between 220° C. and 320° C. and/or at a temperature such that a precursor complex forms; d) subjecting the mixture to a precipitation stage, wherein a precipitate forms, said precipitation stage preferably comprising allowing the mixture to cool and/or adding an antisolvent to the mixture; and e) heating the precipitate at a temperature between 600° C. and 900° C. and/or at a temperature such that a cubic Y.sub.2O.sub.3 crystal structure forms, preferably for at least 10 minutes.

An object of the present invention is to provide an infrared light-emitting phosphor which emits light in a wavelength range where the sensitivity of a detector is high by combination with a semiconductor light-emitting element that emits light in the visible light region, and to provide an infrared light-emitting device using the infrared light-emitting phosphor. The object can be achieved with a light-emitting device including a semiconductor light-emitting element that emits ultraviolet light or visible light and a phosphor that absorbs ultraviolet light or visible light emitted from the semiconductor light-emitting element and emits light in the infrared region, wherein an emission peak wavelength in the infrared region of the phosphor emitting in the infrared region is from 750 to 1,050 nm, and the half width of an emission peak waveform is more than 50 nm.

A pearlescent pigment for security purposes according to an embodiment of the present invention includes a single or a plurality of coating layers containing a metal oxide and an organic or inorganic fluorescent material. Since the pearlescent pigment for security purposes according to the present disclosure includes a fluorescent layer containing the organic or inorganic fluorescent material, it can be used as a pigment for security purposes due to its optical characteristics and can also provide effects such as magnetism, high color intensity, multiple colors, etc. Also, since the pearlescent pigment for security purposes has aesthetic benefit and security characteristic at the same time, it is economical, easy to use and applicable in various industries.

Examples of a monolithic phosphor composite for measuring a parameter of an object are disclosed. The ceramic metal oxide phosphor composite is used in an optical device for measuring the parameter of the measuring object. The device comprises a fiber optic probe with a light guide, a light source operatively coupled to the fiber optic probe to provide excitation light into the light guide, a monolithic ceramic metal oxide phosphor composite functionally coupled to a tip of the fiber optic probe, a sensor operatively coupled to the fiber optic probe to detect the emitted light and a processing unit functionally coupled to the sensor to process the emitted light. The monolithic ceramic metal oxide phosphor composite can be embedded in a notch made into the object or can be adhered to a surface of the object with a binder. When the monolithic ceramic metal oxide phosphor composite is illuminated with the excitation light it emits light in a wavelength different from the excitation light and a change in emission intensity at a single wavelength or the change in intensity ratio of two or more wavelengths, a shift in emission wavelength peak or a decay time of the phosphor luminescence is a function of the measuring parameter.

Persistent infrared (IR) phosphors are disclosed. In an embodiment a phosphor has the general formula: M1.sub.(m−k)Ga.sub.(2n−x−y−z)M2.sub.pO.sub.(rm+3n+2p:xSb.sup.3+,yM3,zD,kM4, wherein M1 is chosen from magnesium, calcium, barium, strontium, zinc, scandium, yttrium, lanthanum, gadolinium, lutetium, or bismuth, or combinations thereof; M2 is chosen from silicon, germanium, tin, titanium, zirconium, or combinations thereof; M3 is chosen from magnesium, aluminum, indium, scandium, or combinations thereof; M4 is chosen from praseodymium, neodymium, samarium, europium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or combinations thereof; D is chosen from chromium, iron, nickel, manganese, or cobalt, or combinations thereof; and wherein 1≤m≤4; 1≤n≤3; 0≤p≤5; 0.0002≤x≤2n; 0≤y≤2n; 0.0001≤z≤0.1; 0≤k≤0.1; and r is selected from 1, 1.5, 2, 2.5, and 3.

The present invention relates to an in vitro method for detecting and/or quantifying a biological or chemical substance of interest in a liquid sample, by a capillary action test using, as probes, photoluminescent inorganic nanoparticles, of formula A.sub.1-xLn.sub.xVO.sub.4(1-y)(PO.sub.4).sub.y (II), in which Ln is selected from europium (Eu), dysprosium (Dy), samarium (Sm), neodymium (Nd), erbium (Er), ytterbium (Yb), thulium (Tm), praseodymium (Pr), holmium (Ho) and mixtures thereof; A is selected from yttrium (Y), gadolinium (Gd), lanthanum (La), lutetium (Lu), and mixtures thereof; 0<x<1; and 0≤y<1, said method employing detection of the luminescence, with an emission lifetime shorter than 100 ms, of the nanoparticles, after one-photon absorption, by excitation of the matrix at a wavelength less than or equal to 320 nm.

It also relates to a capillary action test device comprising, as probes, the aforementioned nanoparticles, as well as the use of such a method for purposes of in vitro diagnostics.

The present invention includes: a radiation detecting unit including a fluorescent body expressed by the formula ATaO.sub.4: B, C (in the formula, A is selected from at least one kind of element from among rare-earth elements involving 4f-4f transitions, B is selected from at least one kind of element, different from A, from among rare-earth elements involving 4f-4f transitions, and C is selected from at least one kind of element from among rare-earth elements involving 5d-4f transitions); an optical fiber that transmits photons generated by the fluorescent body; a light detector that converts the photons transmitted via the optical fiber 3 one by one into electrical pulse signals; a counter that counts the number of electrical pulse signals converted by the light detector; an analysis and display device 6 that obtains a radiation dose rate on the basis of the number of electrical pulse signals counted by the counter.

Examples of a monolithic phosphor composite for measuring a parameter of an object are disclosed. The ceramic metal oxide phosphor composite is used in an optical device for measuring the parameter of the measuring object. The device comprises a fiber optic probe with a light guide, a light source operatively coupled to the fiber optic probe to provide excitation light into the light guide, a monolithic ceramic metal oxide phosphor composite functionally coupled to a tip of the fiber optic probe, a sensor operatively coupled to the fiber optic probe to detect the emitted light and a processing unit functionally coupled to the sensor to process the emitted light. The monolithic ceramic metal oxide phosphor composite can be embedded in a notch made into the object or can be adhered to a surface of the object with a binder. When the monolithic ceramic metal oxide phosphor composite is illuminated with the excitation light it emits light in a wavelength different from the excitation light and a change in emission intensity at a single wavelength or the change in intensity ratio of two or more wavelengths, a shift in emission wavelength peak or a decay time of the phosphor luminescence is a function of the measuring parameter.