Enhancement of the photothermal performance of silver nanoparticle grating films <i>via</i> graphene deposition

Plasmonic devices have emerged as promising alternatives for the current light-collection and energy-harnessing systems. This study presents a plasmonic photothermal film fabricated using a polydimethylsiloxane mold to imprint a narrow grating pitch onto an Ag nanoparticle (AgNP) film, considerably enhancing the light absorption of the film and increasing plasmon-induced absorption <i>via</i> the integration of graphene layers. The AgNP grating films were fabricated using the protocol established in our previous study by incorporating an additional step of the deposition of multilayer graphene onto the films. The surface plasmon resonance (SPR)-enhanced photothermal effect was investigated using a thermoelectric device under white-light irradiation by placing the plasmonic film on the hot side of the device. The AgNP grating film featuring multilayer graphene exhibited a substantially higher temperature than the evaporated Ag film over time under light irradiation at a fixed incident angle. Simultaneous localized SPR and grating-coupled propagating SPR excitations contributed to the enhancement of photothermal currents, and the interaction between graphene and plasmons further intensified the heat generation. Notably, the incorporation of multilayer graphene on the AgNP grating film considerably improved the performance, demonstrating a 6.72-fold increase in heat generation compared with that of the reference flat Ag film. These findings confirm the efficacy of improving the optoelectronic applications using plasmonic films with graphene deposition.