Single-step printing of metallic nanoparticles in 2D micropatterns

This work demonstrates a single-step method for synthesis and printing of metallic nanoparticles (NPs) in 2D micropatterns. The method is based on femtosecond laser writing, enabling fast and high precision deposition of silver, gold, or copper NPs in space-selective areas, which in general is not achieved by the traditional chemical routes or laser ablation of metal. Such finds were accomplished by employing laser-induced forward transfer in the femtosecond pulse regime (fs-LIFT). The results are promising for application, since metallic NPs, with a lognormal diameter distribution averaging between ~ 4 and 30 nm, allow exploring plasmon bands throughout the visible spectrum. The mechanisms behind NP formation by fs-LIFT are discussed based on the thermomechanical response of the material. An estimative based on the heat transfer suggests the occurrence of mechanical fragmentation rather than material vaporization. The main result addressed herein, however, is the ability to deposit silver, gold, and copper nanoparticles in selected regions, supporting the development of NP-based devices via one-step processing and their application in sensors and photonic circuits.