Method of producing silver nanoparticles, and silver paste containing silver nanoparticles

A method of producing silver nanoparticles, comprising:

• a mixing step of mixing a thermally decomposable silver compound, an amine compound having 5 or less carbon atoms, and a solvent including an organic solvent having an octanol/water partition coefficient Log POW of 2.0 to 4.0 at a temperature at which the silver compound and the amine compound do not chemically react;
• a first heating step of heating a mixed liquid obtained in the mixing step to a first temperature lower than a decomposition temperature of the silver compound to generate nuclei of the silver nanoparticles in the mixed liquid;
• and
• a second heating step of heating the mixed liquid containing nuclei of the silver nanoparticles to a second temperature equal to or higher than a decomposition temperature of the silver compound to generate the silver nanoparticles in the mixed liquid.

A silver paste including silver nanoparticles and an organic solvent, wherein

• the silver nanoparticles include silver serving as a core and an amine compound having 5 or less carbon atoms attached to the surface thereof;
• a ratio (MNH2/MAg) of the number of moles of the amine compound to the number of moles of silver serving as the core is 1 or less;
• and
• even if the particles are left under an environment of 25° C. for 10 months, aggregates with a size of 1 μm or more are not observed in measurement using a grind gauge.