Determination of a localized surface plasmon resonance mode of Cu₇S₄ nanodisks by plasmon coupling

Abstract

Plasmon properties such as peak position, extinction cross-section and local electric field intensity are strongly dependent on excited, localized surface plasmon resonance (LSPR) modes. In non-spherical copper chalcogenide nanoparticles, assignment of the LSPR peaks to the corresponding oscillation modes has been controversial and requires experimental verification. We determined the in-plane LSPR mode of roxbyite Cu7S4 nanodisks from the plasmon coupling effect of nanodisks in solution. Compared with individual Cu7S4 nanodisks, self-assembled Cu7S4 nanodisk arrays in chloroform exhibited a blue-shifted LSPR peak with weaker optical density. This strongly suggests that the singular LSPR peak in the near-infrared region mainly originates from the in-plane oscillation mode. In addition, we demonstrate that the same LSPR peak can be readily tuned by controlling the number of disks in the array.

Plasmonic doped semiconductor nanocrystals: Properties, fabrication, applications and perspectives

“…Interparticle plasmon coupling was found to be most prominent when Cu sulfide nanodisks are aligned in a side-by-side arrangement, leading to dipole-dipole coupling between the in-plane LSPR modes, with red shifts (Δλ) reaching up to 419 ± 8.2 nm for the closest-packed side-by-side arrangement The strength of coupling increased with decreasing distance. [150] A much weaker coupling was found by Chen et al [232] in face-to-face assembled Cu 7 S 4 nanodisks. The poor plasmonic coupling of stacks of nanodisks suggests that the LSPR decay length for Cu sulfide nanodisks is anisotropic, due to the inherent anisotropy of the electrical conductivity, which is much greater along one specific crystallographic direction, [237] and of the hole mobility as well.…”

Effect of Concentration on Synthesis of Organic Passivated Cu2-xS Nanoparticles from N-Pyrrolidine Dithiocarbamate Molecular Precursor

“…Such process was more defined when the capping agent concentration was increased. The plasmonic character of the prepared samples indicates an electron deficient copper sulfide stoichiometry [14][15][16]. The SPR is caused by the interaction of oscillating free electrons with light.…”

“…The SPR is caused by the interaction of oscillating free electrons with light. This interaction results in an emergence of a peak in the near infrared region [14,16]. The hexadecylamine-capped nanoparticles showed the short-wavelength SPR in the range of 450-600 nm, while the TOPO-capped nanoparticles revealed a 400-600 nm range.…”

Electrochemical redox-based tuning of near infrared localized plasmons of CuS nanoplates

“…S1 in Supplementary Information). The nanoplates exhibit absorption due to in-plane LSPR mode 29,30 when suspended in toluene and the absorbance peak redshifts as the nanoplate width increases (Fig. 2e).…”