Metal halide colloidal nanoparticles and method for producing the same

A method for producing metal halide colloidal nanoparticles, the method comprising:

• (a) preparing a mixed solution including at least one compound selected from a group consisting of R1COOH, R2NH2, R2R3NH, R2R3R4N, and a first non-polar solvent, wherein R1, R2, R3 and R4 are the same as or different from each other, and each of R1, R2, R3 and R4 independently represents a saturated or unsaturated alkyl group having 2 to 28 carbon atoms;
• (b) adding an alkali metal precursor and a rare-earth metal precursor to the mixed solution and stirring the mixed solution to produce a stirred solution;
• and
• (c) reacting the stirred solution to produce metal halide colloidal nanoparticles represented by a following Chemical Formula 1,
• A3MX6 [Chemical Formula 1]
• wherein in the Chemical Formula 1, A is an alkali metal element, M is a rare-earth metal element, and X is a halogen element.