Inkjet-Based Fabrication Process with Control over the Morphology of SERS-Active Silver Nanostructures

Morphological control of silver nanostructures is sought after due to the dependence of optical properties on size and shape. Herein, we report a facile printing process for fabricating silver nanostructured films with wire-like or particle-like morphologies on paper by merely varying the halide composition of precursor salt from potassium bromo-iodide to potassium chloride. Silver was efficiently retained on the top surface of porous paper substrates by printing an excess of potassium halide salt first, leading to more conductive films at lower silver loadings. Furthermore, Raman characterization results show that silver films having nanoparticle morphology have higher SERS activity than samples with nanowire morphology, although the roughness factor of nanowire films is higher than the corresponding nanoparticulate film. Overall, these findings highlight a facile process for controlling the morphology of SERS-active silver nanostructures, which are fabricated on paper using a desktop inkjet printer.