Abstract: Zinc oxide particles having a polyhedron shape, wherein the crystallite diameter of the [100] plane of the zinc oxide particles is 200 nm or greater. A method for producing the zinc oxide particles, the method including firing a zinc compound in the presence of a molybdenum compound. A resin composition containing the zinc oxide particles and a resin.

Abstract: Provided are metal nanoparticle composite body whose multiple properties, such as a good metal nanoparticle control property, high dispersion stability, a good low-temperature firing property, and ease of purifying and separating metal nanoparticles, are intentionally added and controlled so that practical electrical conductivity can be exhibited, a metal colloidal solution in which the metal nanoparticle composite body is dispersed, and methods for producing these. A metal nanoparticle composite body includes a nitrogen-containing compound (A) and a metal nanoparticle (B), in which the nitrogen-containing compound (A) contains an oxidized nitrogen atom. A metal colloidal solution is obtained by dispersing the metal nanoparticle composite body in a medium. A method for producing a metal colloidal solution is characterized in that metal ions are reduced in a medium in the presence of a nitrogen-containing compound (A) containing an oxidized nitrogen atom so as to form metal nanoparticles (B).

Abstract: Provided are metal nanoparticle composite body whose multiple properties, such as a good metal nanoparticle control property, high dispersion stability, a good low-temperature firing property, and ease of purifying and separating metal nanoparticles, are intentionally added and controlled so that practical electrical conductivity can be exhibited, a metal colloidal solution in which the metal nanoparticle composite body is dispersed, and methods for producing these. A metal nanoparticle composite body includes a nitrogen-containing compound (A) and a metal nanoparticle (B), in which the nitrogen-containing compound (A) contains an oxidized nitrogen atom. A metal colloidal solution is obtained by dispersing the metal nanoparticle composite body in a medium. A method for producing a metal colloidal solution is characterized in that metal ions are reduced in a medium in the presence of a nitrogen-containing compound (A) containing an oxidized nitrogen atom so as to form metal nanoparticles (B).

Abstract: The present invention relates to powder containing silver nanoparticles having an average particle size of 2 to 50 nm in an amount of 95% or more by mass and to applications of the powder. Silver-containing powder containing the silver nanoparticles is obtained by reducing a silver compound in the presence of a compound obtained by bonding polyethylene glycol to polyethyleneimine having a certain molecular weight and then by performing a concentration step and a drying step. A plastic substrate is obtained by directly applying a conductive paste that uses the powder on a plastic substrate and by performing drying.