Symmetry-Breaking Effects of Near-Infrared II Thermoplasmonics of Gold-Silica-Cuprous Selenide Hybrid Nanoshells

Thisstudy presents a numerical investigation of theplasmonicand photothermal properties of Au-silica-Cu2-x Se hybrid nanoshells (Cu2-x Se HNSs) consisting of a silica-Cu2-x Se core-shell nanoshell embedded with a spherical Aucore at varied core offsets. The plasmon modes in the symmetry-brokenCu(2-x )Se HNSs are explained by plasmonhybridization theory in combination with charge density distribution.Results unveil that the hybridized plasmon modes in a symmetry-brokenCu(2-x )Se HNS arise from the interactionof the primitive plasmon modes of the same angular momentum on theAu core and the Cu2-x Se nanoshell.An increase in the core offset redshifts and weakens the near-infraredII (NIR-II) plasmon band corresponding to the low-energy bonding dipolarmode but redshifts and enhances the low-energy bonding quadrupolarmode. At the NIR-II plasmon resonance wavelengths, the temperatureincrease distribution is uniform on the Au core but inhomogeneouson the Cu2-x Se nanoshell. The variationof the temperature increase with the core offset suggests spectraltunability of NIR-II thermoplasmonic properties in the Cu2-x Se HNSs through varying the core offset. Our workprovides a paradigm for rational design of NIR-II plasmonic materialswith optimal photothermal performances for in vivo biomedical applications through symmetry breaking.