Dye molecules on titatium dioxide surface: cluster and periodic surface models
Ligand-Stabilized Au13Cux (x = 2, 4, 8) Bimetallic Nanoclusters: Ligand Engineering to Control the Exposure of Metal Sites
Three novel bimetallic Au-Cu nanoclusters stabilized by a mixed layer of thiolate and phosphine ligands bearing pyridyl groups are synthesized and fully characterized by X-ray single crystal analysis and density functional theory computations. The three clusters have an icosahedral Au13 core face-capped by two, four, and eight Cu atoms, respectively. All face-capping Cu atoms in the clusters are triply coordinated by thiolate or pyridyl groups. The surface ligands control the exposure of Au sites in the clusters. In the case of the Au13Cu8 cluster, the presence of 12 2-pyridylthiolate ligands still leaves open space for catalysis. All the 3 clusters are 8-electron superatoms displaying opti…
Effects of Silver Doping on the Geometric and Electronic Structure and Optical Absorption Spectra of the Au_{25-n}Ag_{n}(SH)_{18}^{-} (n = 1, 2, 4, 6, 8, 10, 12) Bimetallic Nanoclusters
The effect of silver doping of the Au25(SH)18– nanoparticle is studied by investigating Au25–nAgn(SH)18– (n = 1, 2, 4, 6, 8, 10, 12) systems using DFT. For n = 1, doping of the icosahedral shell of the metal core is energetically more favorable than doping of the metal–thiolate units or the center of the core. For n ≥ 2, only doping of the core surface is considered, and arrangements where the silver dopants are in close proximity tend to be slightly less favorable. However, energy differences are small, and all conformations are accessible under experimental conditions. Boltzmann-averaged excitation spectra for these systems show similar features to the undoped Au25(SH)18–. The main differ…
Density-functional tight-binding for beginners
This article is a pedagogical introduction to density-functional tight-binding (DFTB) method. We derive it from the density-functional theory, give the details behind the tight-binding formalism, and give practical recipes for parametrization: how to calculate pseudo-atomic orbitals and matrix elements, and especially how to systematically fit the short-range repulsions. Our scope is neither to provide a historical review nor to make performance comparisons, but to give beginner's guide for this approximate, but in many ways invaluable, electronic structure simulation method--now freely available as an open-source software package, hotbit.
Structural and Theoretical Basis for Ligand Exchange on Thiolate Monolayer Protected Gold Nanoclusters
Ligand exchange reactions are widely used for imparting new functionality on or integrating nanoparticles into devices. Thiolate-for-thiolate ligand exchange in monolayer protected gold nanoclusters has been used for over a decade; however, a firm structural basis of this reaction has been lacking. Herein, we present the first single-crystal X-ray structure of a partially exchanged Au(102)(p-MBA)(40)(p-BBT)(4) (p-MBA = para-mercaptobenzoic acid, p-BBT = para-bromobenzene thiol) with p-BBT as the incoming ligand. The crystal structure shows that 2 of the 22 symmetry-unique p-MBA ligand sites are partially exchanged to p-BBT under the initial fast kinetics in a 5 min timescale exchange reacti…
Atomic Layer Deposition of Aluminum Oxide on TiO2 and Its Impact on N3 Dye Adsorption from First Principles
The atomic layer deposition of aluminum oxide on an OH-terminated TiO2(101) anatase surface was studied employing density functional theory calculations. The formation of the Al2O3−TiO2 interface during the first atomic layer deposition cycle was modeled by studying the dissociative adsorption of an Al(CH3)3 precursor, followed with a H2O-pulse reaction step that changes the surface termination. Calculations provide evidence for the formation of a discontinuous, atomically rough aluminum oxide layer after the first cycle. To explore the role of the aluminum oxide layer on adsorption of a ruthenium-based N3 dye molecule, various adsorption geometries were investigated. Calculations show that…
Modeling the atomic and electronic structure of nanoparticle-ligand interfaces
CCDC 954905: Experimental Crystal Structure Determination
Related Article: Huayan Yang , Yu Wang , Jing Lei , Lei Shi , Xiaohu Wu , Ville Mäkinen , Shuichao Lin , Zichao Tang , Jian He , Hannu Häkkinen , Lansun Zheng , and Nanfeng Zheng|2013|J.Am.Chem.Soc.|135|9568|doi:10.1021/ja402249s
CCDC 954903: Experimental Crystal Structure Determination
Related Article: Huayan Yang , Yu Wang , Jing Lei , Lei Shi , Xiaohu Wu , Ville Mäkinen , Shuichao Lin , Zichao Tang , Jian He , Hannu Häkkinen , Lansun Zheng , and Nanfeng Zheng|2013|J.Am.Chem.Soc.|135|9568|doi:10.1021/ja402249s
CCDC 954904: Experimental Crystal Structure Determination
Related Article: Huayan Yang , Yu Wang , Jing Lei , Lei Shi , Xiaohu Wu , Ville Mäkinen , Shuichao Lin , Zichao Tang , Jian He , Hannu Häkkinen , Lansun Zheng , and Nanfeng Zheng|2013|J.Am.Chem.Soc.|135|9568|doi:10.1021/ja402249s