First-Principles Investigation of Ag-Doped Gold Nanoclusters

Abstract

Gold nanoclusters have the tunable optical absorption property, and are promising for cancer cell imaging, photothermal therapy and radiotherapy. First-principle is a very powerful tool for design of novel materials. In the present work, structural properties, band gap engineering and tunable optical properties of Ag-doped gold clusters have been calculated using density functional theory. The electronic structure of a stable Au20 cluster can be modulated by incorporating Ag, and the HOMO–LUMO gap of Au20−nAgn clusters is modulated due to the incorporation of Ag electronic states in the HOMO and LUMO. Furthermore, the results of the imaginary part of the dielectric function indicate that the optical transition of gold clusters is concentration-dependent and the optical transition between HOMO and LUMO shifts to the low energy range as the Ag atom increases. These calculated results are helpful for the design of gold cluster-based biomaterials, and will be of interest in the fields of radiation medicine, biophysics and nanoscience.

Au19M (M=Cr, Mn, and Fe) as magnetic copies of the golden pyramid

“…Au 19 Li, Au 19 Cu, Au 19 Ag, and Au 19 Pt are found to retain the pyramidal geometry of Au 20 46 – 51 . Increasing the Ag concentration induces the energy gap and optical transition of Au 19− n Ag n 48 , 49 . Au 19 Cu and Au 19 Pd clusters are potential for adsorption of trivalent arsenic 50 .…”

Charge-induced dipole vs. relativistically enhanced covalent interactions in Ar-tagged Au-Ag tetramers and pentamers

“…21 Optical response calculations of mixed gold-silver clusters were investigated by time-dependent density functional theory (TDDFT) in several recent studies (and references within). [22][23][24][25] Determining the geometries of such gas-phase clusters is the first step in studies of their intrinsic properties. Therefore, structural properties of cationic Au-Ag clusters up to five atoms Ag m Au + n (m + n ≤ 5) have been investigated employing ion a) Authors to whom correspondence should be addressed.…”

Optical and electronic properties of mixed Ag-Au tetramer cations

“…[33][34][35][36] From a theoretical point of view, optical properties of Ag-doped Au 20 clusters have been studied by a first principles analysis showing the HOMO-LUMO transitions being shifted to lower photon energies with increasing Ag concentration. 37 Octameric Au m Ag n (m+n=8) clusters have also been investigated using timedependent density functional theory (TDDFT) showing oddeven oscillations of the optical gaps with the variation of the number of gold atoms. 38 In this article, we present photodissociation spectra of Ag n Au + 4−n (n=1-3) clusters in the photon energy range¯ω = 1.9-3.5 eV combined with calculations of the optical response in the framework of TDDFT.…”