We prepared Au/Ag core-shell nanoparticles by growing Ag shell onto 12 nm Au core, using silver nitrate and sodium citrate as the reactants. By changing the molar ratio of Ag to Au, the shell thickness and thus the si...We prepared Au/Ag core-shell nanoparticles by growing Ag shell onto 12 nm Au core, using silver nitrate and sodium citrate as the reactants. By changing the molar ratio of Ag to Au, the shell thickness and thus the size of bimetallic particles could be controlled in convenient way. The formation of core-shell structure was proved by UV-Vis spectra, transmission electron microscopy(TEM), etc.. The core-shell particles showed a more narrow size distribution than Ag colloid prepared without Au core. The SERS activity of the core-shell particles was investigated by using 2,4-dimethylpyridine as the probe, which strongly indicated their potential application in SERS substrate materials.展开更多
The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth ...The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth seeds. The optical property of colloids and the sizes of composite nanoparticles were characterized when the molar ratio of Au to Ag ranges from 4∶1 to 1∶4. The results show that a composite nanoparticle structure similar to strawberry shape is formed at the molar ratio of Au to Ag from 4∶1 to 1∶1; the composite nanoparticles consisting of a core of Au and shell of Ag were generated at the 1∶4 molar ratio, having a striking feature of forming (interconnected) network structure.展开更多
文摘We prepared Au/Ag core-shell nanoparticles by growing Ag shell onto 12 nm Au core, using silver nitrate and sodium citrate as the reactants. By changing the molar ratio of Ag to Au, the shell thickness and thus the size of bimetallic particles could be controlled in convenient way. The formation of core-shell structure was proved by UV-Vis spectra, transmission electron microscopy(TEM), etc.. The core-shell particles showed a more narrow size distribution than Ag colloid prepared without Au core. The SERS activity of the core-shell particles was investigated by using 2,4-dimethylpyridine as the probe, which strongly indicated their potential application in SERS substrate materials.
基金Project(2000E0008Z) supported by Natural Science Foundation of Yunnan Province
文摘The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth seeds. The optical property of colloids and the sizes of composite nanoparticles were characterized when the molar ratio of Au to Ag ranges from 4∶1 to 1∶4. The results show that a composite nanoparticle structure similar to strawberry shape is formed at the molar ratio of Au to Ag from 4∶1 to 1∶1; the composite nanoparticles consisting of a core of Au and shell of Ag were generated at the 1∶4 molar ratio, having a striking feature of forming (interconnected) network structure.
