Light-emitting material and method for producing the same

A light-emitting material comprising a fluoride phosphor having a first composition comprising:

• an alkali metal including K;
• Si;
• Al;
• Mn;
• and F such that when a total number of moles of the alkali metal is 2, a total number of moles of Si, Al, and Mn is in a range from 0.9 to 1.1, a number of moles of Al is in a range from greater than 0 to 0.1, a number of moles of Mn is in a range from greater than 0 to 0.2, and a number of moles of F is in a range from 5.5 to less than 6.0, and
• in an infrared absorption spectrum, the fluoride phosphor has an absorption peak in a wavenumber range from 590 cm−1 to 610 cm−1.

A method for producing a light-emitting material, the method comprising:

• preparing first fluoride particles having a second composition comprising an alkali metal including K, Si, Mn, and F such that when a total number of moles of the alkali metal is 2, a total number of moles of Si and Mn is in a range from 0.9 to 1.1, a number of moles of Mn is in a range from greater than 0 to 0.2, and a number of moles of F is in a range from 5.5 to less than 6.0;
• preparing second fluoride particles having a third composition comprising an alkali metal including K, Al, and F such that when a number of moles of Al is 1, a total number of moles of the alkali metal is in a range from 2 to 3, and a number of moles of F is in a range from 5 to 6;
• and
• subjecting a mixture of the first fluoride particles and the second fluoride particles to a first heat treatment in an inert gas atmosphere at a temperature in a range from 600° C. to 780° C. to produce a first heat-treated material.