Silver (I) and Silver (I, III) Oxide Formation via Femtosecond Laser Micromachining

Abstract

Silver oxides have found numerous applications in catalysis, photocatalysis, data storage, energy storage and nanoparticle fabrication. Current methods of synthesising silver oxides include Pulsed Laser Deposition (PLD), oxygen plasma and ozone generator. Femtosecond laser micromachining has been used for precise surface texturing and to drive interesting chemical reactions on metals. In this thesis, silver (I) and silver (I, III) oxides are formed following femtosecond laser irradiation in ambient air. Numerous laser machining parameters, such as laser wavelength, pulse energy, number of shots and laser repetition rate are investigated to find sets of parameters that form each type of oxide. The laser machined silver is then studied using Raman spectroscopy to map the different silver oxides and to study their distribution on the machined surface. It is found that increasing the number of pulses and the pulse energy favours the formation of both AgO and Ag₂O. A mechanism of formation for AgO is then proposed and the decomposition of the oxides over time is studied.