Synthesis of flexible and sub-microstructured gold thin films with honeycomb cavities

The synthesis of flexible adhesive tapes consisting of a sub-microstructured gold thin film with honeycomb cavities is reported for the first time. The tape was fabricated by transferring the sub-microstructured Au thin film from a rigid substrate to a transparent tape by a “paste and peel off” process. The geometrical properties of the Au honeycomb cavities were extensively analyzed using SEM and AFM images. Their optical properties were characterized by UV-VIS spectroscopy. The extinction spectra exhibit minimum and maximum values centered at 500 nm and 760 nm, respectively. A clear dichroic behavior was demonstrated through the sinusoidal modulation of the absorbance intensity (about 25% of its absolute value) as a function of the polarization angle. Additionally, the Surface-Enhanced Raman Scattering efficiency of the samples was tested using Rhodamine 6 G dye, exhibiting excellent stability and reaching a sensitivity level of 10 − 7 M. These findings open new exciting potential applications in various fields of scientific research. Representative micrographs of the sub-microstructured gold thin film with honeycomb cavities; a) SEM, and b) AFM. • The fabrication of flexible adhesive tapes of a sub-microstructured Au thin film with honeycomb cavities is reported for the first time. • Combination of Nanosphere Lithography and high-energy MeV Ion Hammering to optimize the geometrical characteristics of the honeycomb cavities. • Excellent plasmonic properties and a dichroic behavior of the absorbance intensity as a function of the polarization angle. • Samples tested as Raman-SERS substrates achieving an EF value of about 1.5×10 5 for the detection of Rhodamine R6G.