Au nanostructures by colloidal lithography: from quenching to extensive fluorescence enhancement

Enhanced local electric fields are created by nanoparticles when pumped at wavelengths corresponding to Localised Surface Plasmon Resonance (LSPR) modes, leading to Metal Induced Fluorescence Enhancement (MIFE). This paper describes the fluorescent enhancement due to reproducible and tuneable Au nanostructures on glass substrates fabricated over large areas by colloidal lithography. Interparticle separation, particle resonance, and the fluorescent dye properties (quantum yield and emission/excitation wavelengths) are all important factors influencing the fluorescent enhancement. A maximum fluorescence enhancement of 69 times from near infra-red (NIR) dye Alexa Fluor (R) 790 was observed.