Fluoride fluorescent material, light emitting device, and method for producing fluoride fluorescent material
AssigneeNichia Corporation
InventorTomokazu Yoshida
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Abstract
A fluoride fluorescent material includes a composition including K, Ge, Mn4+, and F and having a molar ratio of K of 2, a total molar ratio of Ge and Mn4+ of 1, a molar ratio of Mn4+ of more than 0 and less than 0.2, and a molar ratio of F of 6 in 1 mol of the composition, has a light emission spectrum having a first light emission peak in a range of 615 nm or more and less than 625 nm having a full width at half maximum of 6 nm or less, and a second light emission peak in a range of 625 nm or more and less than 635 nm, and has an internal quantum of 85% or more efficiency under excitation of light having a wavelength of 450 nm.
Claims10
A method for producing a fluoride fluorescent material, wherein the fluoride fluorescent material has a hexagonal crystal structure, P63mc space group symmetry, the method comprising:
- preparing a precipitate including fluoride particles comprising a composition comprising K, Ge, Mn4+, and F, and having a molar ratio of K of 2, a total molar ratio of Ge and Mn4+ of 1, a molar ratio of Mn4+ of more than 0 and less than 0.2, and a molar ratio of F of 6 in 1 mol of the composition by mixing a first solution containing at least potassium ion and hydrogen fluoride, a second solution containing at least a first complex ion including tetravalent manganese and hydrogen fluoride, and a third solution containing at least a second complex ion including germanium and fluoride ion;
- rinsing the precipitate with a rinsing liquid after solid-liquid separation of the precipitate to obtain the fluoride particles;
- drying the fluoride particles at a temperature in the range of 50° C. or more and 110° C. or less;
- and
- bringing the dried fluoride particles into contact with a fluorine-containing substance, and subjecting to a heat treatment at a temperature in an inert gas atmosphere at a temperature in a range of 450° C. or more and 550° C. or less.
Dependencies are inferred from the claim text.