Metal nanoparticle dispersion and a method of manufacturing the same

PROBLEM TO BE SOLVED: To provide a method for producing a dispersion solution of a metal nanoparticle, which enables to control the shape or particle size of the metal nanoparticle within a wide range, a dispersion solution of a metal nanoparticle, which has excellent dispersion stability, and a method for producing the dispersion solution. SOLUTION: In the production method comprising each process where a metal salt in which the ratio of silver in metallic elements is ≥75 mass%, carboxylic acids and a reducing agent are mixed in a liquid phase, so as to synthesize a metal nanoparticle, and the metal nanoparticle is dispersed into a dispersion medium, the synthesis of the metal nanoparticle is performed by stirring a suspension produced by admixing an additive being as the salt of one or more metallic elements selected from the group consisting of Na, Mg, K, Ca, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Mo, In, Sn, Ba, Pb, Bi and Ce which are different from the metallic elements composing the metal salt and not reduced by the reducing agent in the liquid phase together with the metal salt or the like at 25 to 95°C, and the concentration of the additive in the dispersion solution is reduced, so as to be the range of 0.01 to 100 ppm. COPYRIGHT: (C)2009,JPO&INPIT