Maximizing Fluorescence Enhancement in Metal Nanoantenna Arrays for efficient bioanalytical devices

Our investigation focused on fluorescence enhancement mechanisms using metal nanoantennas with Alexa Fluor-647. By exploiting numerical modelling tools, we fabricated non-interacting Au nanodisc arrays on glass substrates, achieving a maximum fluorescence enhancement factor of 180 at an optimal spacer thickness of approximately 10 nm. Comparative analysis with bare glass substrates revealed significant improvements in excitation and emission dynamics, attributed to nanoscale field confinement and the Purcell effect. Time- and space-resolved photoluminescence measurements unveiled a distance-dependent interaction between the fluorophore and localized plasmons, modulated by thin polyelectrolyte monolayers, with prevalent radiative processes in samples exhibiting maximum signal.