Enhanced Photothermal Heating fromOne-dimensionalAssemblies of Au Nanoparticles Encapsulated byTiO2Shell

One-dimensional assemblies of metal nanoparticles (NPs) may represent an interesting plasmonic superstructure, in which localized surface plasmon resonance of individual NPs can be coupled to modify the strength and wavelength of extinction of metal NPs. In this study, we explored a simple method to assemble Au NPs into a linear chain by utilizing a low-dielectric solvent and salts. The aggregation states of Au NPs were engineered by the concentration of salts, which resulted in isolated and linearly assembled Au NPs. In addition, the TiO(2)shell, as a stabilizing layer, was synthesized on the surface of the isolated and assembled Au NPs by a slow hydrolysis process. Because the linearly assembled Au NPs with a TiO(2)shell had a broad extinction spectrum by plasmon hybridization, they could absorb more photons under simulated solar irradiation. As a result, the linearly assembled Au NPs with a TiO(2)shell exhibited an enhanced photothermal effect, compared with the isolated ones.