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  • Plasmonic Electricity II: T...
    Moskowitz, Joshua; Sindi, Rashad; Geddes, Chris D

    Journal of physical chemistry. C, 03/2020, Letnik: 124, Številka: 10
    Journal Article

    In a recent paper, our laboratory has shown that fluorophores in close proximity to a non-continuous metal nanoparticle film can induce a detectable electrical current in the film. This current was found directly proportional to the fluorophore extinction coefficient and concentration when excited with p-polarized light. This finding threatens to change the way we both think about and use fluorescence spectroscopy as no longer do we have to use and are limited by traditional photodetectors and associated optics to collect and measure fluorescence signatures. This approach holds potential to significantly simplify fluorescence-based instrumentation. In this paper, we significantly expand upon our previous findings and show that plasmonic current is a function of the nanoparticle size and spacing in the film, which is explained by the concentric sphere model for nanoparticle capacitance. We also demonstrate the dependence of plasmonic current on the relative permittivity of the solvent, and that in an excess of salt, the fluorophore-induced current is significantly greater than the background current. This paves the way for downstream plasmonic assays in a variety of biological media. In addition, we have measured plasmonic current as a function of both applied bias voltage and temperature, allowing for the optimization of the fluorophore-induced plasmonic current. These findings allow for not only a better understanding of plasmonic current but also its optimization as it relates to fluorescence-based detection.