Gas-phase synthesis of mesoporous films of Ag/C:H:N:O core-satellite nanoparticles for surface-enhanced Raman spectroscopy

Abstract Rapid development in the field of detection of biomolecules by surface-enhanced Raman spectroscopy (SERS) is enabled by enormous progress in the nanofabrication that nowadays allows for the tailor-made production of nanomaterials that can serve as effective and reliable SERS-active platforms. Among others, heterogeneous mesoporous coatings constitute an important class of nanomaterials that receives increasing attention. In this study, we investigate the possibility of producing such nanomaterials using a novel, one-step, and fully solvent-free technique. This approach employs the in-flight decoration of gas-phase synthesized C:H:N:O plasma polymer cores with nanometre-sized silver nanoparticles. Such physically produced Ag/C:H:N:O core-satellite nanoparticles upon deposition on a planar substrate spontaneously form mesoporous nanoparticle films with SERS-active Ag nanoparticles evenly distributed on the surface of supporting C:H:N:O cores. As shown, such produced nanomaterials exhibit, due to their structure, the SERS enhancement factor of (1.1 ± 0.2) × 106, i.e., the enhancement factor one order of magnitude higher than the value 1 × 105 typically reported for silver nanostructures prepared by commonly used magnetron sputtering onto planar substrates.