Inorganic metal halide compound, a method of manufacturing the same, and an optical member, a light-emitting device, and an apparatus, each including the inorganic metal halide compound

A method of manufacturing an inorganic metal halide compound represented by Formula 1 and having a double perovskite structure, wherein the method comprises the steps of:

• obtaining a first solution by stirring a precursor of A and a precursor of M1;
• obtaining a second solution by stirring a precursor of M3 and a precursor of Z;
• and
• mixing the first solution and the second solution, to make the inorganic metal halide compound;
• (A)2(M1)(M3)(X)6:Z Formula 1
• wherein, in Formula 1,
• A and M1 are each, independently from one another, a monovalent inorganic-cation, wherein M1 is not Na+ and A and M1 are different from each other,
• M3 is a trivalent metal-cation,
• X is a halide anion, and
• Z is bismuth or a metalloid, doped in (A)2(M1)(M3)(X)6.