Formation of highly dispersed AuAg nanoalloys by femtosecond laser irradiation of metal salts in normal hexane

The interaction of an intense femtosecond laser pulses with a neat liquid solvent has been known to produce a number of highly reactive species that may useful to induce chemical reaction in the solution through the nonlinear mechanism such as multiphoton absorption [1]. When two or more metal ions are present in the solution, they readily react with the ions, radicals, molecules or excited states generated photolytically from the solvent to form zerovalent metal nanoalloys. We have reported elsewhere that the formation of gold-silver (AuAg) alloy nanoparticles in aqueous phase is possible by irradiating the mixed Au and Ag ions solution using a tightly focused femtosecond laser pulses [2]. The homogenous AuAg alloy nanoparticles as small as 2 nm were synthesized in all compositions, but its formation yield is very low and they are found to be gold-riched nanoalloys due to low concentration of ions used to avoid the formation of AgCl precipitation. By changing the solvent with an organic liquid, AgCl precipitates can be avoided and the resulted nanoparticles will be more dispersed, high yield and true alloys. Here, we demostrate the formation of AuAg alloy nanoparticles by femtosecond irradiation of metal ions co-existed in normal hexane.