▎ 摘　　要

NOVELTY - Preparing ultrafine silver powder involves preparing graphene carrying silver seed crystals, dispersing graphene oxide in solvent water to obtain a graphene oxide dispersion, then dissolving soluble silver salt in solvent water to obtain a soluble silver salt solution, and adding a soluble silver salt solution to the graphene oxide dispersion, stirring, and centrifuging. The solid obtained by centrifugation is dispersed in a solvent water to prepare a silver oxide-containing graphene oxide dispersion, and heated the solution to a reaction temperature to add a solution of a reducing agent to carried out a liquid phase reduction reaction. After the end, the reaction solution is cooled to room temperature, filtered, washed with a filter cake, and dried to obtain the graphene carried the silver seed crystal. The graphene-supported ultrafine silver powder is then prepared, and dispersed the graphene loaded with silver seed crystal in solvent water. USE - Method for preparing ultrafine silver powder is used for a positive silver paste of a photovoltaic cell. ADVANTAGE - The method enables to prepare ultrafine silver powder, that has simple and easy process, good dispersibility of silver, high electron mobility and good electrical conductivity. DETAILED DESCRIPTION - Preparing ultrafine silver powder involves preparing graphene (1-1) carrying silver seed crystals, dispersing graphene oxide in solvent water to obtain a graphene oxide dispersion, then dissolving soluble silver salt in solvent water to obtain a soluble silver salt solution, and adding a soluble silver salt solution to the graphene oxide dispersion, stirring, and centrifuging. The solid obtained by centrifugation is dispersed in a solvent water to prepare a silver oxide-containing graphene oxide dispersion, and heated the solution to a reaction temperature to add a solution of a reducing agent to carried out a liquid phase reduction reaction. After the end, the reaction solution is cooled to room temperature, filtered, washed with a filter cake, and dried to obtain the graphene carried the silver seed crystal. The graphene-supported ultrafine silver powder is then prepared, and dispersed the graphene loaded with silver seed crystal in solvent water to obtain a graphene dispersion carrying silver seed crystal, and added a soluble silver salt solution to the graphene dispersion carried the silver seed crystal, and raised the temperature to the reaction temperature. The reaction mother liquid is obtained by stirring, and a solution of a reducing agent is added dropwise to the reaction mother liquid to carried out a liquid phase reduction reaction. After the reaction is completed, the reaction liquid is cooled to room temperature. After filtering, washed the filter cake, and dried, and the graphene-loaded ultrafine silver powder is obtained.