Au@Ag core-shell nanoparticles have received considerable attention for recent years because of the localized surface plasmon resonance (LSPR). At present, Au@Ag core-shell nanoparticles have been widely used in applications related to photonics, catalysis, information storage, chemical/biological sensing. Due to the well controlled size and morphology of Ag shell, seed-mediated growth method has become the most practical approach to synthesize Au@Ag core-shell nanoparticles. This review provides a short summary of some main factors, such as the morphology and concentration of Au seeds, concentration of AgNO₃, capping agents, reductants and some other factors, which affect the size, morphology, the thickness and uniform coating of Ag shell during the seed-mediated growth of Au@Ag core-shell nanoparticles. Recent studies have shown that Au@Ag core-shell nanoparticles would benefit the further development of the surface-enhanced Raman scattering (SERS).

Contents
1 Introduction
2 Classification of Au@Ag core-shell nanoparticles
3 Preparation of Au@Ag core-shell nanoparticles by seed-mediated growth method
3.1 Precursors
3.2 Capping agents
3.3 Reductants
3.4 Some other factors
4 Conclusion