Computational Approaches to the Electronic Properties of Noble Metal Nanoclusters Protected by Organic Ligands

Abstract

Organometallic nanoparticles composed by metal cores with sizes under two nanometers covered with organic capping ligands exhibit intermediate properties between those of atoms and molecules on one side, and those of larger metal nanoparticles on the other. In fact, these particles do not show a peculiar metallic behavior, characterized by plasmon resonances, but instead they have nonvanishing band-gaps, more along molecular optical properties. As a consequence, they are suitable to be described and investigated by computational approaches such as those used in quantum chemistry, for instance those based on the time-dependent density functional theory (TD-DFT). Here, I present a short review of the research performed from 2014 onward at the University of Modena and Reggio Emilia (Italy) on the TD-DFT interpretation of the electronic spectra of different organic-protected gold and/or silver nanoclusters.

Gold‐Doping Effect on Two‐Photon Absorption and Luminescence of Atomically Precise Silver Ligated Nanoclusters

“…Notable mismatch of experimental and simulated spectra is located at 400–500 nm, the region of ligand states contribution. Impact of organic ligands on the absorption spectra is notably emphasized in the particular case of charged silver nanoclusters [12] . Detailed analysis of influence of choice of functionals on structure and absorption spectra Ag 24 Au 1 has been presented in ref.…”

“…Impact of organic ligands on the absorption spectra is notably emphasized in the particular case of charged silver nanoclusters. [12] Detailed analysis of influence of choice of functionals on structure and absorption spectra Ag 24 Au 1 has been presented in ref. [13].…”

SERS-Based Sensor Using Subnanometric Copper–Silver Mixed Clusters Ag(8–n)Cun (n = 0–8) for Pyridine: A DFT Study

“…The vertical excited states, the corresponding electronic transitions, and the ultraviolet–visible (UV–vis) spectra of the complexes were calculated using time-dependent density functional theory (TD-DFT) with three functionals, i.e., the generalized gradient approximation (GGA) PBE , (0% Hartree–Fock), the global hybrid GGA PBE0 (25% HF), and the range-separated hybrid GGA functional CAM-B3LYP (19% HF and 65% HF at small and large interelectronic distances, respectively). These functionals were recommended in several works of Ag–Au mixed clusters − and Cu-guanidine complex . The simple PBE functional can fairly estimate the lowest excitation energy but often fails to reproduce the overall shape of the UV–vis spectra.…”

Oxygen‐Vacancy‐Induced Formation of Pt‐Based Intermetallics on MXene with Strong Metal‐Support Interactions for Efficient Oxygen Reduction Reaction

“…[14] Nevertheless, the rearrangement of Pt and M atoms to form ordered structure requires higher temperature to overcome the atomic diffusion barrier, inevitably leading to an increase in particle size and a reduction in electrochemically active surface areas (ECSA). In general, surface coating strategies, such as oxide shells and organic capping ligands, [15][16][17] etc., are employed to prevent nanoparticles (NPs) agglomeration. However, this may lower the catalytic activity of PtM to some extent for the blocked active sites caused by surfacecoated materials.…”