Synthesis and optical properties of silver nanoparticles stabilized by gemini surfactant

Silver nanoparticles were prepared by the reduction of silver nitrate using NaBH4 as reducing agent in water-in-oil reverse micelles system, in which gemini surfactant 2-hydroxy-1, 3-bis(octadecyldimethylammonium) propane dibromide (18-3(OH)-18) was used as stabilizer. The results of TEM, AFM and UV–vis absorption spectra show that the silver nanoparticles have a narrow size distribution. The results of UV–vis absorption spectra and XPS reveal that the gemini surfactant 18-3(OH)-18 can stabilize the silver nanoparticles for at least 2 months. The 18-3(OH)-18-capped silver nanoparticles exhibit visible luminescence at 448 nm upon photoexcitation at 309 nm due to metal–ligand charge transfer absorption.