Combination of Digestive Ripening and Seeding Growth As a Generalized Route for Precisely Controlling Size of Monodispersed Noble Monometallic, Shell Thickness of Core-Shell and Composition of Alloy Nanoparticles

On the basis of combining the effect of digestive ripening and seeding growth, a generalized route for precisely controlling the size of noble monodisperse (MD) nanoparticles (NPs), the shell thickness of core-shell NPs, and composition of alloy NPs has been reported. First, small NPs are dispersed in high-boiling-point organic solvent as seeds; second, an alkyl amine-containing metal complex is used as the NP precursor; and finally, the metal atoms are reduced by the alkyl amine and grow on the surface of the seeds to form large NPs. The combining effect of seeding growth and digestive ripening render this route the ability to precisely control the size and maintain monodispersity. Through adjusting the reactive conditions, various MD noble NPs (Ag, Au, Pd), core-shell NPs (Ag@Pd, Pd@Au, Pd@Ag, Au@Pd, Au@Ag, Pt@Au, and Pt@Pd), and alloy nanoparticles(Ag/Au) can be prepared. The diameter, shell thickness, and composition of MID NPs can be precisely controlled by adjusting the ratio of the precursor/seed, offering a flexible route to tune surface plasmonic properties. Through increasing the digestive time, the core-shell NPs can be easily transformed to alloy NPs. By adjusting the composition and size of the used core-shell NPs, alloy NPs with tunable composition and size are achievable. Additionally, as-prepared core-shell NPs can be employed as starting materials to build other nanostructured NPs.