scholarly journals Aluminum Doping Effect on Surface Structure of Silver Ultrathin Films

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 648
Author(s):  
Han Yan ◽  
Xiong Xu ◽  
Peng Li ◽  
Peijie He ◽  
Qing Peng ◽  
...  
Keyword(s):  
Density Functional ◽  
Near Infrared ◽  
Single Layer ◽  
Density Functional Theory Calculations ◽  
Light Transmittance ◽  
Formation Mechanisms ◽  
Silver Surface ◽  
Silver Films ◽  
Migration Pathway ◽  
Surface Morphologies

Ultrathin silver films with low loss in the visible and near-infrared spectrum range have been widely used in the fields of metamaterials and optoelectronics. In this study, Al-doped silver films were prepared by the magnetron sputtering method and were characterized by surface morphology, electrical conductivity, and light transmittance analyses. Molecular dynamics simulations and first-principles density functional theory calculations were applied to study the surface morphologies and migration pathway for the formation mechanisms in Al-doped silver films. The results indicate that the migration barrier of silver on a pristine silver surface is commonly lower than that of an Al-doped surface, revealing that the aluminum atoms in the doping site decrease the surface mobility and are conducive to the formation of small islands of silver. When the islands are dense, they coalesce into a single layer, leading to a smoother surface. This might be the reason for the observably lower 3D growth mode of silver on an Al-doped silver surface. Our results with electronic structure insights on the mechanism of the Al dopants on surface morphologies might benefit the quality control of the silver thin films.

Ab Initio Calculation of Mechanical Properties of Stacking Fault in 3C-SiC: Effect of Stress and Doping

2012 ◽  
Vol 717-720 ◽  
pp. 415-418
Author(s):  
Yoshitaka Umeno ◽  
Kuniaki Yagi ◽  
Hiroyuki Nagasawa
Keyword(s):  
Mechanical Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Stacking Faults ◽  
Single Layer ◽  
Local Strain ◽  
Density Functional Theory Calculations ◽  
Stacking Fault ◽  
Functional Theory ◽  
N Doping

We carry out ab initio density functional theory calculations to investigate the fundamental mechanical properties of stacking faults in 3C-SiC, including the effect of stress and doping atoms (substitution of C by N or Si). Stress induced by stacking fault (SF) formation is quantitatively evaluated. Extrinsic SFs containing double and triple SiC layers are found to be slightly more stable than the single-layer extrinsic SF, supporting experimental observation. Effect of tensile or compressive stress on SF energies is found to be marginal. Neglecting the effect of local strain induced by doping, N doping around an SF obviously increase the SF formation energy, while SFs seem to be easily formed in Si-rich SiC.

scholarly journals CCCCC pentadentate chelates with planar Möbius aromaticity and unique properties

2016 ◽  
Vol 2 (8) ◽  
pp. e1601031 ◽  
Author(s):  
Congqing Zhu ◽  
Caixia Yang ◽  
Yongheng Wang ◽  
Gan Lin ◽  
Yuhui Yang ◽  
...  
Keyword(s):  
Photothermal Therapy ◽  
Density Functional ◽  
Near Infrared ◽  
Chelating Agent ◽  
Density Functional Theory Calculations ◽  
Infrared Region ◽  
Carbon Chain ◽  
Broad Absorption ◽  
Functional Theory ◽  
Potential Applications

The coordinating atoms in polydentate chelates are primarily heteroatoms. We present the first examples of pentadentate chelates with all binding atoms of the chelating agent being carbon atoms, denoted as CCCCC chelates. Having up to five metal-carbon bonds in the equatorial plane has not been previously observed in transition metal chemistry. Density functional theory calculations showed that the planar metallacycle has extended Craig-Möbius aromaticity arising from 12-center–12-electron dπ-pπ π-conjugation. These planar chelates have broad absorption in the ultraviolet-visible–near-infrared region and, thus, notable photothermal performance upon irradiation by an 808-nm laser, indicating that these chelates have potential applications in photothermal therapy. The combination of facile synthesis, high stability, and broad absorption of these complexes could make the polydentate carbon chain a novel building block in coordination chemistry.

scholarly journals Strain and electric field tunable electronic structure of buckled bismuthene

RSC Advances ◽  
2017 ◽  
Vol 7 (63) ◽  
pp. 39546-39555 ◽  
Author(s):  
Ming-Yang Liu ◽  
Yang Huang ◽  
Qing-Yuan Chen ◽  
Ze-Yu Li ◽  
Chao Cao ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Electric Field ◽  
First Principles ◽  
Density Functional ◽  
Single Layer ◽  
Density Functional Theory Calculations ◽  
Two Dimensional ◽  
Functional Theory

Based on first-principles density functional theory calculations, we systemically study the properties of two-dimensional buckled single-layer bismuth (b-bismuthene).

scholarly journals Adsorption and diffusion characteristics of lithium on hydrogenated α- and β-silicene

2017 ◽  
Vol 8 ◽  
pp. 1742-1748
Author(s):  
Fadil Iyikanat ◽  
Ali Kandemir ◽  
Cihan Bacaksiz ◽  
Hasan Sahin
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Energy Surface ◽  
Diffusion Mechanism ◽  
Single Layer ◽  
Density Functional Theory Calculations ◽  
Binding Energies ◽  
Functional Theory ◽  
Diffusion Characteristics ◽  
And Diffusion

Using first-principles density functional theory calculations, we investigate adsorption properties and the diffusion mechanism of a Li atom on hydrogenated single-layer α- and β-silicene on a Ag(111) surface. It is found that a Li atom binds strongly on the surfaces of both α- and β-silicene, and it forms an ionic bond through the transfer of charge from the adsorbed atom to the surface. The binding energies of a Li atom on these surfaces are very similar. However, the diffusion barrier of a Li atom on H-α-Si is much higher than that on H-β-Si. The energy surface calculations show that a Li atom does not prefer to bind in the vicinity of the hydrogenated upper-Si atoms. Strong interaction between Li atoms and hydrogenated silicene phases and low diffusion barriers show that α- and β-silicene are promising platforms for Li-storage applications.

scholarly journals From Ru-bda to Ru-bds: a step forward to highly efficient molecular water oxidation electrocatalysts under acidic and neutral conditions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Yang ◽  
Lei Wang ◽  
Shaoqi Zhan ◽  
Haiyuan Zou ◽  
Hong Chen ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Density Functional ◽  
Bond Formation ◽  
Density Functional Theory Calculations ◽  
Oxidation Catalyst ◽  
Nucleophilic Attack ◽  
Molecular Water ◽  
Formation Mechanisms ◽  
Equatorial Position ◽  
Neutral Conditions

AbstractSignificant advances during the past decades in the design and studies of Ru complexes with polypyridine ligands have led to the great development of molecular water oxidation catalysts and understanding on the O−O bond formation mechanisms. Here we report a Ru-based molecular water oxidation catalyst [Ru(bds)(pic)2] (Ru-bds; bds2− = 2,2′-bipyridine-6,6′-disulfonate) containing a tetradentate, dianionic sulfonate ligand at the equatorial position and two 4-picoline ligands at the axial positions. This Ru-bds catalyst electrochemically catalyzes water oxidation with turnover frequencies (TOF) of 160 and 12,900 s−1 under acidic and neutral conditions respectively, showing much better performance than the state-of-art Ru-bda catalyst. Density functional theory calculations reveal that (i) under acidic conditions, the high valent Ru intermediate RuV=O featuring the 7-coordination configuration is involved in the O−O bond formation step; (ii) under neutral conditions, the seven-coordinate RuIV=O triggers the O−O bond formation; (iii) in both cases, the I2M (interaction of two M−O units) pathway is dominant over the WNA (water nucleophilic attack) pathway.

scholarly journals Disordered hyperuniformity in two-dimensional amorphous silica

2020 ◽  
Vol 6 (16) ◽  
pp. eaba0826 ◽  
Author(s):  
Yu Zheng ◽  
Lei Liu ◽  
Hanqing Nan ◽  
Zhen-Xiong Shen ◽  
Ge Zhang ◽  
...  
Keyword(s):  
Amorphous Silica ◽  
Density Functional ◽  
Large Scale ◽  
Single Layer ◽  
Topological Defects ◽  
Density Functional Theory Calculations ◽  
Density Fluctuations ◽  
Atomic Scale ◽  
Two Dimensional ◽  
Wave Localization

Disordered hyperuniformity (DHU) is a recently proposed new state of matter, which has been observed in a variety of classical and quantum many-body systems. DHU systems are characterized by vanishing infinite-wavelength normalized density fluctuations and are endowed with unique novel physical properties. Here, we report the discovery of disordered hyperuniformity in atomic-scale two-dimensional materials, i.e., amorphous silica composed of a single layer of atoms, based on spectral-density analysis of high-resolution transmission electron microscopy images. Moreover, we show via large-scale density functional theory calculations that DHU leads to almost complete closure of the electronic bandgap compared to the crystalline counterpart, making the material effectively a metal. This is in contrast to the conventional wisdom that disorder generally diminishes electronic transport and is due to the unique electron wave localization induced by the topological defects in the DHU state.

Sign in / Sign up

Export Citation Format

Share Document