Research On Direct Femtosecond Laser Processing Of Gold-silver Alloy Nanostructure By Photoreduction

Nanometallic compound materials have excellent optical and electricalproperties, the research based on of the nano metallic compound materials isvery important for the application in the field of physics, chemistry and so on.Compared with monometallic material, the SERS effect, catalytic propertiesand other properties such as surface plasmon resonance of the bimetallicnanomaterials have more excellent performance. In recent years, the researchof gold and silver nano-material has attracted more and more attention.Theproperty of the silver metal material is unstable,making its application limited inmany fields.Though, the gold metal material is stable, its performance in thefield of biology and other areas is not so well as silver metal materials. So thereserch of gold and silver compound nano-materials is of great significance.The excess use of NaBH4may cause the adsorption of unused BH4-ionsonto the nanoparticle surface resulting in the borides contamination on thenanoparticle surface. In addition, as the phase transfer agent and the stabilizerare sometimes chemically different, and the reducing agent was usedexcessively,The cleaning afterward is still an issue in this technique. Based onthe above points, laser irradiation becomes an alternative way due to theadvantage of being free from preadded reducing agents. Even though γ-rayand synchrotron X-ray irradiation sources are highly efficient, these methodshave some drawbacks such as radioactivity and poor accessibility.Instead,femtosecond laser irradiation method seems to be more promising inphotoreductions due to its simple, safe and “green” properties. The formationof bimetallic Au-Ag nanoparticles by the intense laser irradiation of the mixedhexane solution of Au and Ag ions can be attributed to the generation of highenergetic electrons and hydrogen radicals produced during the laserirradiation.Arbitrary graphs of assembled micro-nano structures can be achieved byVisual Basic program controlling the laser spot. As the different ratio of goldand silver affect the physical and chemical properties of the nano-structrues, the research of different ratios of ion precursor solution is necessary to thegold and silver nano-structure. By adjusting the ion precursor solution ratiothe proportion of gold and siliver in the nanostructures can be controlled anddeposited on the substrate. The bimetallic structures retain the properties ofmicro-nano metal material which is relatively stable, non-perishable in the air,and has good continuity and integrity.In recent years, with the rapid development of micro/nano devices, thesystem of metallic nano-structure does not exist independently.The flexibleintegration of bimetallic materials and functional devices has become thefocus. In this study, taking advantage of femtosecond laser processing, goldand silver nano-structures shown with clusters or particles were reductedunder the processing of laser photodynamic reduction reaction deposited ontomicrofluidic substrate and they can form arbitrary patterns.The experimentalresearch of the application of gold and silver nano-structures in catalysis,microfluidic chips, self-driven micro-mechanical and other areas, and theanalysis of the feasibility are in progress. This bimetallic nanostructures willpromote catalysis, and produce large amounts of air bubbles in a short timeresulting in laid the foundation for its application in the self-drivenmicro-mechanical and other fields.The precursor solution prepared by phase transfer method is not limited tothe gold and silver solution. A variety of metal precursor solution based on thismethods can be prepared, such as iron (Fe)、platinum (Pt) and so on.Therefore, this method can be extended to the preparation of a variety ofbimetallic nanocomposites.