The present invention provides a low-dimensional perovskite-structured metal halide and a preparation method and application thereof. The general formulas of the compositions of the low-dimensional perovskite-structured metal halide are AB.sub.2X.sub.3, A.sub.2BX.sub.3, and A.sub.3B.sub.2X.sub.5; wherein, A is at least one of Li, Na, K, Rb, Cs, In, and Tl; B is at least one of Cu, Ag, and Au; and X is at least one of F, Cl, Br, and I.

A potassium hexafluoromanganate (K2MnF6) composition includes no more than six parts per million of each of one or more Group 13 elements, no more than 520 parts per million of one or more alkaline earth metals, no more than fourteen parts per million of one or more transition metals, and/or no more than forty parts per million of calcium. A method for providing this composition, as well as lighting apparatuses, backlight units, and electronic devices including phosphors formed from the composition also are provided.

A light emitting component comprising a light source (10) for emitting blue light (aa), a first layer (1) comprising a red phosphor, and a second layer (2) comprising luminescent crystals (20). Upon absorption of the light emitted by the light source (10), the luminescent crystals (20) emit light of a wavelength in the green light spectrum (cc). The first layer (1) is arranged adjacent to the light source (10). The second layer (2) is arranged remotely from the first layer (1).

The invention refers in a first aspect to a solid polymer composition (100) comprising green luminescent crystals (1), non-perovskite red phosphor particles, and a polymer (3). The polymer (3) has a molar ratio of the sum of (oxygen+nitrogen) to carbon z, wherein z≤0.9, z≤0.75 in particular z≤0.4, in particular z≤0.3, in particular z≤0.25. A second aspect of the invention refers to a self-supporting film comprising the solid polymer composition (100) of the first aspect. A third aspect of the invention refers to a light emitting device comprising either the solid polymer composition (100) according to the first aspect of the invention or the self-supporting film according to the second aspect of the invention.

A white light emitting device comprises: an LED that generates excitation light of wavelength from 420 nm to 480 nm; and photoluminescence materials that generate light with a peak emission wavelength from 500 nm to 650 nm comprising a broadband phosphor, and a manganese-activated narrowband red fluoride phosphor with a peak emission wavelength from 628 nm to 640 nm and a full width at half maximum of less than 30 nm. The device generates white light with a selected color temperature from 2200K to 6500K, a General Color Rendering Index, CRI Ra, of at least 80, and a Duv (Delta u, v) from 0.0060 to 0.0170 for the selected color temperature and wherein the device has an LER (Luminous Efficacy of Radiation) of at least 320 lm/W.sub.opt.

A sol-gel process for synthesizing a luminescent material has a general formulation: AxByFz:Mn. A is an element of group 1, 2, 4, NR.sub.4 or a combination of elements belonging to those groups, with R═H or an alkyl chain or a combination of chains. B is an element of group 5, 6, 13, 14 and 0<x≤5, 0<y≤2, 5≤z≤7. The sol-gel process includes a) producing a liquid precursor (2, 3) in an alcohol solution by mixing metal reagents (1) with manganese, the mixture being made at pH<8; b) obtaining a solid precursor (5, 6) from the liquid precursor (2, 3) obtained in step a), by eliminating (4) the solvent; c) crystallizing (7, 70) the solid precursor (5, 6) obtained in step b) by thermal treatment in fluorinated atmosphere; and d) retrieving the fluorescent crystalline powder (8) obtained at an end of step c).

High photoluminescence, high stability, inorganic perovskite compounds comprising an alkali metal selected from potassium (K), rubidium (Rb), and cesium (Cs); copper (Cu); and at least one halogen selected from chlorine (Cl), bromine (Br), and iodine (I). The perovskites may be free of lead (Pb). The inorganic perovskite compound may be used in an optoelectronic device. The optoelectronic device optionally contains a phosphor such as a blue-emitting phosphor. The inorganic perovskite compound may be used as an anti-counterfeiting nanotaggant applied on or within an object that susceptible to counterfeiting to enable confirmation of an authentic object.

A luminescent material represented by Formula 1, a method of preparing the same, and a light-emitting device including the same:
[A.sup.1.sub.nA.sup.2.sub.3][B.sub.2][X.sup.1.sub.mX.sup.2.sub.5]  Formula 1 A.sup.1, A.sup.2, B, X.sup.1, X.sup.2, n, and m in Formula 1 are as defined in the specification.

A potassium hexafluoromanganate is represented by General Formula: K.sub.2MnF.sub.6, and a diffuse reflectance with respect to light having a wavelength of 310 nm is 20% or more.

Disclosed are quantum dots including a luminescent dopant. More particularly, each of the quantum dots according to an embodiment of the present invention includes a core and a shell surrounding the core, wherein at least one of an interior of the core and an interface between the core and the shell is doped with a luminescent group I dopant.