A process for coating a phosphor of formula I: A.sub.x[MF.sub.y]:Mn.sup.4+ includes combining the phosphor of formula I in particulate form with a first solution including a compound of formula II: A.sub.x[MF.sub.y] to form a suspension and combining a second solution with the suspension, the second solution including a precursor including an element selected from the group consisting of calcium, strontium, magnesium, yittrium, barium, scandium, lanthanum, and combinations thereof. A population of particles having a core including a phosphor of formula I and a manganese-free composite coating disposed on the core, and a lighting apparatus (10) including the population of particles are also presented.

A device for converting solar radiation is described wherein the device comprises an inorganic luminescent material comprising a host material doped with Mn5+ ions for converting radiation of the UV and/or visible part of the electromagnetic spectrum into radiation of the near-infrared radiation part of the electromagnetic spectrum, preferably the infrared part between 1150 nm and 1250 nm, preferably around 1190 nm (the infrared emission peak of Mn.sup.5+); or, an amorphous host material doped with Sm.sup.2+ or Tm.sup.2+ ions, the amorphous host material including the elements Al, Si, O and N (SiAION) for converting radiation of the UV and/or visible part of the electromagnetic spectrum into radiation of a longer wavelength, preferably a longer wavelength between 650 n and 800 nm or a longer wavelength of around 1140 n; and, at least one photovoltaic device for converting at least part of the converted radiation into electrical power.

The present application discloses a method of preparing a luminescent nano-sheet. The method includes preparing a precursor emulsion solution containing a metal halide and RNH.sub.3X, and having a molar ratio of metal halide to RNH.sub.3X in a range of approximately 0.6 to approximately 0.8; demulsifying the precursor emulsion solution to obtain a perovskite quantum dots material and a demulsified solution; and forming the luminescent nano-sheet by allowing the perovskite quantum dots material self-assemble into the luminescent nano-sheet. X is a halide, R is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, and heterocyclyl.

The present application discloses a method of preparing a luminescent nano-sheet. The method includes preparing a precursor emulsion solution containing a metal halide and RNH.sub.3X, and having a molar ratio of metal halide to RNH.sub.3X in a range of approximately 0.6 to approximately 0.8; demulsifying the precursor emulsion solution to obtain a perovskite quantum dots material and a demulsified solution; and forming the luminescent nano-sheet by allowing the perovskite quantum dots material self-assemble into the luminescent nano-sheet. X is a halide, R is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, and heterocyclyl.

Provided herein are organic-inorganic hybrid-perovskites, including metal halide perovskites having a 1D crystal structure. The metal halide perovskites may be luminescent. The metal halide perovskites may include a dopant, including an emitter dopant. Methods of forming metal halide perovskites, and devices including the metal halide perovskites also are provided.

Provided herein are organic-inorganic hybrid-perovskites, including metal halide perovskites having a 1D crystal structure. The metal halide perovskites may be luminescent. The metal halide perovskites may include a dopant, including an emitter dopant. Methods of forming metal halide perovskites, and devices including the metal halide perovskites also are provided.

A method for producing a γ-AlON fluorescent material, comprising: preparing a first mixture containing a compound containing Mn, a compound containing Li, a compound containing Mg, an aluminum oxide, and an aluminum nitride, in which the amount of fluorine is 150 ppm by mass or less relative to the total amount of the first mixture excluding fluorine, and subjecting the first mixture to a first heat treatment to obtain a first calcined product having an average particle diameter D1, as measured according to a Fisher Sub-Sieve Sizer method, of 10.0 μm or more; and preparing a second mixture containing the first calcined product, a compound containing Mn, a compound containing Li, a compound containing Mg, an aluminum oxide, and an aluminum nitride, in which the amount of fluorine is 150 ppm by mass or less relative to the total amount of the second mixture excluding fluorine, and subjecting the second mixture to a second heat treatment to obtain a second calcined product having an average particle diameter D2, as measured according to the Fisher Sub-Sieve Sizer method, of 16.0 μm or more, wherein the second mixture contains the first calcined product in an amount of more than 20% by mass and 82% by mass or less.

A method for producing a γ-AlON fluorescent material, comprising: preparing a first mixture containing a compound containing Mn, a compound containing Li, a compound containing Mg, an aluminum oxide, and an aluminum nitride, in which the amount of fluorine is 150 ppm by mass or less relative to the total amount of the first mixture excluding fluorine, and subjecting the first mixture to a first heat treatment to obtain a first calcined product having an average particle diameter D1, as measured according to a Fisher Sub-Sieve Sizer method, of 10.0 μm or more; and preparing a second mixture containing the first calcined product, a compound containing Mn, a compound containing Li, a compound containing Mg, an aluminum oxide, and an aluminum nitride, in which the amount of fluorine is 150 ppm by mass or less relative to the total amount of the second mixture excluding fluorine, and subjecting the second mixture to a second heat treatment to obtain a second calcined product having an average particle diameter D2, as measured according to the Fisher Sub-Sieve Sizer method, of 16.0 μm or more, wherein the second mixture contains the first calcined product in an amount of more than 20% by mass and 82% by mass or less.

Provided are phosphor particles comprising Mn-doped complex fluoride red phosphor particles and inorganic fine particles which are affixed to the surface of each red phosphor particle. The Mn-doped complex fluoride red phosphor-containing phosphor particles are suppressed in mutual adhesion and agglomeration, flow well during mixing with a silicone or epoxy resin, and have excellent humidity resistance.

Provided are phosphor particles comprising Mn-doped complex fluoride red phosphor particles and inorganic fine particles which are affixed to the surface of each red phosphor particle. The Mn-doped complex fluoride red phosphor-containing phosphor particles are suppressed in mutual adhesion and agglomeration, flow well during mixing with a silicone or epoxy resin, and have excellent humidity resistance.