Ultrafast laser-induced formation of AgO and Ag2O on silver

Ultrafast lasers have been widely used to texture materials, and while a lot of focus has been placed on controlling surface morphology, literature is lacking on ultrafast laser-induced surface chemistry, even though surface chemistry is essential in many applications. To better understand surface chemistry changes during ultrafast laser ablation, a femtosecond laser was used here to irradiate silver samples in air. The laser ablated craters were analysed with Raman spectroscopy and reveal the formation of Ag 2 O and AgO at different pulse energies and number of pulses. A mechanistic picture for the formation of both silver oxides and their transformation into Ag 2 CO 3 , Ag 2 SO 3 and Ag 2 SO 4 is proposed. Some laser-induced periodic surface structures LIPSSs were also observed on some craters, as well as nanoparticles arranged in concentric patterns. • Ag 2 O and AgO were formed while machining silver with a femtosecond laser. • Number of pulses and pulse energy influenced the types and amount of oxide. • Ag 2 CO 3 and Ag 2 SO 3 /Ag 2 SO 4 were formed when the silver oxide aged in ambient air. • LIPSSs and concentric rings were found when viewing the craters under SEM. • A mechanistic picture is proposed to understand oxide formation and decomposition.