White light-assisted projection printing of submicron plasmonic nanostructures for advanced nanofabrication

Plasmonic nanoparticle printing from colloidal solutions is a vital facet of nanofabrication, offering unique advantages such as direct writing, a bottom-up approach, and on-demand printing for sensing, electronic devices, and healthcare applications. Despite its potential, plasmonic nanoprinting faces significant challenges in becoming practicable due to the limitations of the current techniques, such as complex setup, high cost, tedious process, and the usage of time-consuming spot scan techniques using lasers for pattern generation. Herein, for the first time, a novel white light-assisted projection printing technique (PPT) is demonstrated for fabricating plasmonic nanostructures. This notably simple approach can easily print arbitrary plasmonic patterns in just a few seconds. Additionally, submicron patterning capability is demonstrated with an impressive line width of ∼400 nm. More importantly, conductive patterns are achieved without additional post-treatments, such as annealing. Optothermal parallel trapping of biological cells and grayscale patterning for surface-enhanced Raman spectroscopy is demonstrated, showcasing the potential applications of the printing technique for advanced nanofabrication. The superior performance of this technique surpasses that of the existing optical printing technique, paving the way toward advanced nanofabrication for emerging applications.