Laser Printing of Silver and Silver Oxide

TL;DR

This paper demonstrates laser printing of silver and silver oxide using femtosecond laser writing, showing how photoinitiator addition controls oxide formation and resistivity, enabling functional THz devices.

Contribution

It introduces a method to selectively deposit silver or silver oxide via femtosecond laser writing with photoinitiator control, advancing printable conductive and functional materials.

Findings

Laser writing results in silver and silver oxide deposition depending on conditions.

Photoinitiator addition suppresses silver oxide formation and reduces resistivity.

Printed silver oxide enables THz polarizer and metamaterial fabrication.

Abstract

We show that direct laser writing in aqueous silver nitrate with a $\lambda$ = 1030 nm femtosecond laser results in deposition of a mixture of silver oxide and silver, in contrast to the pure silver deposition previously reported with 780 nm femtosecond direct laser writing. However, adding photoinitiator prevents silver oxide formation in a concentration-dependent manner. As a result, the resistivity of the material can also be controlled by photoinitiator concentration with resistivity being reduced from approximately 9e-3 $\Omega$m to 3e-7 $\Omega$m. Silver oxide peaks dominate the X-ray diffraction spectra when no photoinitiator is present, while the peaks disappear with photoinitiator concentrations above 0.05 wt%. A THz polarizer and metamaterial are printed as a demonstration of silver oxide printing.