Laser Direct Writing of Silver Nanowire with Amino Acids-Assisted Multiphoton Photoreduction

We have demonstrated an approach of silver nanostructure micro fabrication by femtosecond laser direct writing of silver ion aqueous solution containing biocompatible amino acids with different molecular architectures. The amino acids-assisted multiphoton photoreduction (MPR) lowers the incident femtosecond laser threshold to 0.32 mW for glycine, 0.72 mW for valine, 0.6 mW for proline, and 0.35 mW for leucine. The line widths of the silver nanowires are varied with the composition of the biocompatible amino acids. The highest resolution of 186 nm has been achieved. Furthermore, the corresponding electrical conductivities of silver nanowires are determined to be 1.48 X 10(-6), 4.1 X 10(-7), 7.04 X 10(-7), and 1.35 X 10(-6) Omega m, which have been significantly improved compared to that of the previously reported silver wires fabricated by MPR microfabrication. The proposed protocol for fabricating silver nanostructure would pave the way for fabricating metallic nanostructures and play an extremely important role in the micro/nanofabrication for biological application and the field of photonics.