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Title: Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18

Abstract

Here we investigate via first-principles simulations the optical absorption spectra of three different Au30(SR)18 monolayer-protected clusters (MPC): Au30(StBu)18, which is known in the literature and whose crystal structure is available, and two species – Au30(SPh)18 and Au30(SPh-pNO2)18 – which have been designed by replacing the tert-butyl organic residues with aromatic ones so as to investigate the effects of ligand replacement on the optical response of Au nanomolecules. In analogy with previously studied but rather different Au23(SR)16- anionic species, a substantial ligand-enhancement of the absorption intensity in the optical region is obtained for the Au30(SPhpNO2)18 neutral MPC. This demonstrates that using conjugated aromatic ligands with properly chosen electron withdrawal substituents and exhibiting steric hindrance so as to also achieve charge decompression at the surface is a general approach to enhance MPC photo-absorption intensity in the optical region. Moreover, the ligand-enhancement phenomenon is subjected to a detailed analysis based on fragment projection of electronic excited states and on induced transition densities, leading to a better understanding of its physical origin, thus opening avenues to its more precise control and exploitation.

Authors:
; ; ; ; ORCiD logo; ORCiD logo; ORCiD logo; ORCiD logo
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1364002
Report Number(s):
PNNL-SA-123164
Journal ID: ISSN 1932-7447; 49097; 49645; KP1704020
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 20; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Environmental Molecular Sciences Laboratory

Citation Formats

Sementa, Luca, Barcaro, Giovanni, Baseggio, Oscar, De Vetta, Martina, Dass, Amala, Apr?, Edoardo, Stener, Mauro, and Fortunelli, Alessandro. Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18. United States: N. p., 2017. Web. doi:10.1021/acs.jpcc.6b12029.
Sementa, Luca, Barcaro, Giovanni, Baseggio, Oscar, De Vetta, Martina, Dass, Amala, Apr?, Edoardo, Stener, Mauro, & Fortunelli, Alessandro. Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18. United States. doi:10.1021/acs.jpcc.6b12029.
Sementa, Luca, Barcaro, Giovanni, Baseggio, Oscar, De Vetta, Martina, Dass, Amala, Apr?, Edoardo, Stener, Mauro, and Fortunelli, Alessandro. Tue . "Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18". United States. doi:10.1021/acs.jpcc.6b12029.
@article{osti_1364002,
title = {Ligand-Enhanced Optical Response of Gold Nanomolecules and Its Fragment Projection Analysis: The Case of Au 30 (SR) 18},
author = {Sementa, Luca and Barcaro, Giovanni and Baseggio, Oscar and De Vetta, Martina and Dass, Amala and Apr?, Edoardo and Stener, Mauro and Fortunelli, Alessandro},
abstractNote = {Here we investigate via first-principles simulations the optical absorption spectra of three different Au30(SR)18 monolayer-protected clusters (MPC): Au30(StBu)18, which is known in the literature and whose crystal structure is available, and two species – Au30(SPh)18 and Au30(SPh-pNO2)18 – which have been designed by replacing the tert-butyl organic residues with aromatic ones so as to investigate the effects of ligand replacement on the optical response of Au nanomolecules. In analogy with previously studied but rather different Au23(SR)16- anionic species, a substantial ligand-enhancement of the absorption intensity in the optical region is obtained for the Au30(SPhpNO2)18 neutral MPC. This demonstrates that using conjugated aromatic ligands with properly chosen electron withdrawal substituents and exhibiting steric hindrance so as to also achieve charge decompression at the surface is a general approach to enhance MPC photo-absorption intensity in the optical region. Moreover, the ligand-enhancement phenomenon is subjected to a detailed analysis based on fragment projection of electronic excited states and on induced transition densities, leading to a better understanding of its physical origin, thus opening avenues to its more precise control and exploitation.},
doi = {10.1021/acs.jpcc.6b12029},
journal = {Journal of Physical Chemistry. C},
issn = {1932-7447},
number = 20,
volume = 121,
place = {United States},
year = {2017},
month = {1}
}

Works referencing / citing this record:

Modulating photo-luminescence of Au 2 Cu 6 nanoclusters via ligand-engineering
journal, January 2017