Title
Structural And Electronic Properties Of Micellar Au Nanoparticles: Size And Ligand Effects
Keywords
AFM; Au nanoparticle; DFT; EXAFS; FEFF simulation; size effects; strain; TEM; XAFS; XANES
Abstract
Gaining experimental insight into the intrinsic properties of nanoparticles (NPs) represents a scientific challenge due to the difficulty of deconvoluting these properties from various environmental effects such as the presence of adsorbates or a support. A synergistic combination of experimental and theoretical tools, including X-ray absorption fine-structure spectroscopy, scanning transmission electron microscopy, atomic force microscopy, and density functional theory was used in this study to investigate the structure and electronic properties of small (∼1-4 nm) Au NPs synthesized by an inverse micelle encapsulation method. Metallic Au NPs encapsulated by polystyrene 2-vinylpiridine (PS-P2VP) were studied in the solution phase (dispersed in toluene) as well as after deposition on γ-Al2O3. Our experimental data revealed a size-dependent contraction of the interatomic distances of the ligand-protected NPs with decreasing NP size. These findings are in good agreement with the results from DFT calculations of unsupported Au NPs surrounded by P2VP, as well as those obtained for pure (ligand-free) Au clusters of analogous sizes. A comparison of the experimental and theoretical results supports the conclusion that the P2VP ligands employed to stabilize the gold NPs do not lead to strong distortions in the average interatomic spacing. The changes in the electronic structure of the Au-P2VP NPs were found to originate mainly from finite size effects and not from charge transfer between the NPs and their environment (e.g., Au-ligand interactions). In addition, the isolated ligand-protected experimental NPs only display a weak interaction with the support, making them an ideal model system for the investigation of size-dependent physical and chemical properties of structurally well-defined nanomaterials. © 2014 American Chemical Society.
Publication Date
7-22-2014
Publication Title
ACS Nano
Volume
8
Issue
7
Number of Pages
6671-6681
Document Type
Article
Personal Identifier
scopus
DOI Link
https://doi.org/10.1021/nn406568b
Copyright Status
Unknown
Socpus ID
84904768342 (Scopus)
Source API URL
https://api.elsevier.com/content/abstract/scopus_id/84904768342
STARS Citation
Behafarid, Farzad; Matos, Jeronimo; Hong, Sampyo; Zhang, Lihua; and Rahman, Talat Shahnaz, "Structural And Electronic Properties Of Micellar Au Nanoparticles: Size And Ligand Effects" (2014). Scopus Export 2010-2014. 8660.
https://stars.library.ucf.edu/scopus2010/8660