Preparation method for surface-enhanced raman scattering substrate based on nano-silver particles

The invention discloses a low-cost green chemical synthesis method for nano-silver particles and a preparation method for a surface raman-enhanced active substrate based on the nano-silver particles. By utilizing the principle that silver ions are reduced by aldehyde groups in a silver mirror reaction, a trace amount of a silver-ammino complex solution is added into an aldehyde-group-contained compound solution with a certain concentration at the room temperature, so that the silver ions are reacted fully and reduced into elemental silver and generate the nano-silver particles. The nano-silver particles obtained by adopting the chemical synthesis method are even in particle size (diameters are between 35 nm to 38 nm), and good in monodispersity. Then, a synthetic nano-silver particle solution is directly dropped on a glass sheet or other carrier such as a silicon slice and an organic polymer film, after the solution is evaporated to be dry completely, a coffee-ring effect after a liquid drop is evaporated to