Enhancement of nanofluidic ionic current via plasmon-mediated effect

Abstract

Localized surface plasmon resonance (LSPR) has been extensively used in various applications, but the comprehension of its role in plasmon-mediated photochemical and photothermal effects on ionic currents is still in its infancy. To improve the efficiency of optofluidic systems, it is imperative to investigate the ion transport behavior influenced by LSPR within electrolytes. In this study, we employ a 3D nanochannel network membrane (NCNM) integrated micro/nanofluidic device to elucidate the mechanisms underlying plasmon-mediated ionic current enhancement. By analyzing ionic currents generated by laser irradiation versus thermal heating, our results indicate that the photoelectrochemical effect, which increases the space charge density, plays a more significant role in ionic current enhancement than pure thermal effects. Furthermore, our investigation of various structural parameters shows that optimizing laser power absorption through the 3D NCNM is crucial for effective ionic current generation. This research represents a fundamental step in the understanding of plasmon-mediated ionic transport mechanisms and provides insights into efficient light-to-ionic transport conversion. These findings have potential for a wide range of applications, including photoinduced energy harvesting devices, ionic pumps and wavelength-selective nanochannels, such as fluidic rhodopsin systems.