Size-Dependent Optical Properties of Aluminum Nanoparticles: From Classical to Quantum Description

Abstract

The absorption spectra of a series of tetrahedral-shaped aluminum nanoparticles (ANPs) with side lengths ranging from L = 1.4 to 141.4 nm have been calculated. The size-dependent evolution of structures and spectra has been demonstrated. The plasmon resonance of ANPs is highly sensitive to the particle size and spans a wide spectral region from ultraviolet to visible. As L increases from 70 to 141 nm, an apparent spectral red shift is still observed, although their spectral line shapes do not change much. For the small clusters Aln with n ≤ 560 (or with L ≤ 3.68 nm), their absorption spectra have been calculated by both the real-time time-dependent density functional theory (RT-TDDFT) scheme and the finite difference time domain (FDTD) classical electrodynamics method, whereas for the larger nanoparticles, their absorption spectra have only been calculated by the FDTD method. Aln with n ≤ 560 has two main absorption bands attributed to two kinds of localized surface plasmon resonance modes, vertexes and e...