Size- and Surface-Dependent Photoresponses of Solution-Processed Aluminum Nanoparticles

Abstract

Plasmonic aluminum nanoparticles have emerged as an exciting new materials platform, due to the high natural abundance of aluminum, their ability to be synthesized in the solution phase, and the potential of these materials to be used for photocatalysis and sensing. However, the photothermal properties of solution-processed aluminum nanoparticles, particularly how phonon energy transfer depends on particle size and surface properties, are critical for practical applications and are currently unexplored. Here, we use transient absorption spectroscopy, in combination with simulations of phonon and thermal energy dissipation, to investigate the photoresponses of aluminum nanoparticles of various diameters (54, 85, 121, and 144 nm) suspended in 2-propanol. Fast thermal transfer rates to the solvent (170-280 ps) are observed for particles of all sizes and are facilitated by native oxide coverage, as verified with a two-interface thermal energy-transfer model. Size-dependent phonon “breathing”/vibrational modes...