Nanoplasmonic Photothermal Heating and Near-Field Enhancements: A Comparative Survey of 19 Metals

Abstract

Localized surface plasmon resonances optically excited in metallic nanoparticles (NPs) produce beneficial thermal and nonthermal effects. Nonthermal effects, such as enhancing and localizing fields on subwavelength scales and photo-generating hot carriers, have been extensively exploited, while interest in highly localized photothermal heating is reviving. Both effects may work together synergistically, such as increasing the efficiency of a photocatalytic process, or they may work against each other, such as accelerating the desorption of analytes in surface-enhanced spectroscopy. To compare how these effects depend on the composition and size of the NP, we report a quantitative survey of thermal and nonthermal properties in the visible-solar (1.7–4.1 eV) and ultraviolet (3.1–6.2 eV) ranges for 19 metals, including conventional plasmonic materials (gold, silver, copper), an alkaline earth metal (magnesium), post-transition metals (aluminum, gallium, indium), and a wide variety of transition metals. Figures of merit that reflect the resistive losses and electric field enhancement factor of the NPs were used in this comparative analysis.