Large-Area, Ultrahigh-Enhancement, and Array-Type Hot Spots in Plasmonic Nanocube Dimer-on-Film Nanocavity

The competition and synergy of plasmonic modes are of great importance for electromagnetic enhancement and manipulation of hot spots, enabling wide applications in plasmon-enhanced spectroscopy, photocatalysis, and photovoltaic. However, attainment of high-performance hot spots in plasmonic dimer-on-film nanocavity constitutes a challenging task. Herein, we have theoretically explored properties of hot spots in the system of Au@SiO2 nanocube dimer on Au film, and further revealed (1) large-area hot spots at the intergap between nanocubes; (2) ultrahigh-enhancement hot spots on corners of Au core; and (3) array-type hot spots at the interface between nanocubes and film. Moreover, the coupling modes have been manipulated efficiently by changing the thickness of the shell and arrangements of nanocubes. These findings inspire and guide the design of advanced nanostructures, opening opportunities for the development of devices such as photodetectors, biosensors, nanolasers, and imaging sensors.

Automated summary

By theoretical exploration, we have discovered high-performance hot spots in the system of Au@SiO2 nanocube dimer on Au film, including large-area hot spots at the intergap between nanocubes, ultrahigh-enhancement hot spots on corners of Au core, and array-type hot spots at the interface between nanocubes and film. The coupling modes have been efficiently manipulated by changing the thickness of the shell and arrangements of nanocubes. These findings inspire and guide the design of advanced nanostructures, opening opportunities for the development of devices such as photodetectors, biosensors, nanolasers, and imaging sensors.