Inkjet printing of silver rainbow colloids for SERS chips with polychromatic sensitivity

Pristine and artificially mixed silver colloids of diverse anisotropic silver nanoparticles were used as rainbow colloidal silver inks for inkjet printing of cellulose-based active elements with polychromatic sensitivity for surface-enhanced Raman spectroscopy optical sensors. Platelet silver nanocrystallites possessing different plasmonic bands in the visual spectral range were grown in water-polyol liquors of different viscosities to prevent nanoparticle agglomeration and provide colloidal stability for at least one year. SERS tests of model photostable dyes revealed bright enhanced signals under several standard wavelengths of laser irradiations thus demonstrating better practical applications of such substrates.