Under water laser assisted ablation of alloyed metal nanoparticles for surface plasmonic application

Abstract

Liquid assisted laser ablation on a rotating target has become a key synthesis method for generating metal alloy nanoparticles with their controlled geometry and crystallinity. The laser ablation of metal targets in liquid environments is considered as a reliable alternative to traditional chemical reduction methods for obtaining metal colloids, since such a strategy is considered environmental friendly (“green” technique) with products which frequently do not need stabilizing molecules or other chemical precursor. Laser ablation-based synthesis can be executed in deionized water or even in biologically-compatible aqueous solutions like Acetone, Isopropyl alcohol, Ethanol etc. On the other hand, metal nanoparticles are often susceptible to oxidation and aggregation (thus reducing their free energy), leading to a loss of their physical properties. Therefore, several efforts are taken to protect metal nanoparticles with inert shells, to preserve them from surface modifications and to keep their main characteristics unchanged. In this M.Tech thesis we have synthesized Al, Cu-Al and NiTialloy nanoparticles with different laser fluences (30,40,50 J/cm2), wavelengths (1064,532,355 nm), Rotational speeds (10,20,30 RPM) but with a constant flow rate of liquid medium. The main objective is to study morphology, crystallinity and optical propertyof these metal alloy nanoparticles for Suface Plasmonic application. The Particles shape, surface morphology, size and crystallinity were analyzed through SEM, DLS and XRD characterizations respectively. UV-Vis is used to check the absorption of nanoparticles and thermal analysis of NiTi particles is done by DSC.