scholarly journals The origins of charge separation in anisotropic facet photocatalysts investigated through first-principles calculations

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18500-18508
Author(s):  
Shun-Chiao Chan ◽  
Yu-Lin Cheng ◽  
Bor Kae Chang ◽  
Che-Wun Hong

The anisotropic (110)/(100) facet junction built-in potential in SrTiO3 is estimated at 2.9 V using DFT for the first time, which can help in further design and development of efficient photocatalysts using such anisotropic-facet engineering.

2020 ◽  
Vol 22 (17) ◽  
pp. 9677-9684 ◽  
Author(s):  
Mehdi Ghambarian ◽  
Zahra Azizi ◽  
Mohammad Ghashghaee

A drastic improvement in the phosgene sensitivity of black phosphorene with defect engineering is reported for the first time within a periodic density functional theory framework.


2015 ◽  
Vol 17 (2) ◽  
pp. 1093-1098 ◽  
Author(s):  
Sheng-Yi Xie ◽  
Xian-Bin Li ◽  
Wei Quan Tian ◽  
Nian-Ke Chen ◽  
Yeliang Wang ◽  
...  

Based on first-principles calculations, we designed for the first time a boron-kagome-based two-dimensional MgB6 crystal, in which two boron kagome layers sandwich a triangular magnesium layer.


2017 ◽  
Vol 72 (4) ◽  
pp. 295-301 ◽  
Author(s):  
Li Li ◽  
Zhao-Yi Zeng ◽  
Ting Liang ◽  
Mei Tang ◽  
Yan Cheng

AbstractThe influence of pressure on the elastic and mechanical properties of the hexagonal transition-metal dichalcogenide WS2 is investigated using the first-principles calculations. With the increase in pressure, the lattice parameters and the volume of WS2 decrease, which is exactly in agreement with the available experimental data and other calculated results. The elastic constants Cij, bulk modulus B, shear modulus G, Young’s modulus E, and Poisson’s ratio σ of WS2 also increase with pressure. At last, for the first time, the band gaps of energy, the partial density of states, and the total density of states under three different pressures are obtained and analysed. It is found that the band gap of WS2 decreases from 0.843 to 0 eV when the external pressure varies from 0 to 20 GPa, which implies that WS2 may transform from semiconductors to semimetal phase at a pressure about 20 GPa.


2016 ◽  
Vol 30 (03) ◽  
pp. 1650007
Author(s):  
Naeemullah ◽  
G. Murtaza ◽  
R. Khenata ◽  
S. Bin Omran

For the first time, the electronic and optical properties of the quaternary Be[Formula: see text]Mg[Formula: see text]Zn[Formula: see text]Se alloy have been investigated using first-principles calculations within the framework of density functional theory (DFT). Variations in the direct band gap with the change in [Formula: see text] and [Formula: see text] compositions show agreement with the experimental measurements. Evaluation of the dielectric function and refractive index reveals the optical activity in the visible and ultraviolet energy regions.


2020 ◽  
Vol 8 (25) ◽  
pp. 12457-12462
Author(s):  
Zhonglong Zhao ◽  
Gang Lu

Two-dimensional bimetallenes are explored for the first time as promising electrocatalysts for CO2 conversion by extensive first-principles calculations.


2014 ◽  
Vol 1642 ◽  
Author(s):  
Alexandre Berche ◽  
Jean-Claude Tédenac ◽  
Philippe Jund ◽  
Stéphane Gorsse

ABSTRACTLiterature data of the Mn-Si system is analyzed and discordances are pointed out. First principles calculations are performed to clarify the enthalpies of formation of the intermetallic phases. Especially the enthalpies of formation of the various possible structures of the MnSix are discussed. On the basis of these new data, a thermodynamic description of the Gibbs energy of the phases is performed using the Calphad method. The system Ge-Mn is also assessed using the Calphad method for the first time.The mixing enthalpy in the D88 solid solution is calculated between Mn5Ge3 and Mn5Si3 by DFT calculations.Finally a thermodynamic description of the ternary system is suggested. Especially the solubility of germanium in MnSix is modeled.


1993 ◽  
Vol 313 ◽  
Author(s):  
D. Welter ◽  
J. Sticht ◽  
G.R. Harp ◽  
R.F.C. Farrow ◽  
R.F. Marks ◽  
...  

ABSTRACTThe Magneto-optical Kerr effect of CoPt3 ordered compounds and alloys is investigated experimentally and analyzed theoretically using first principles band structure calculations.The calculations confirm the experimental results and allow for the first time a detailed, bandstructure based interpretation of the electronic transitions leading to the well known strong uv peak at around 4eV. This feature can be unambiguously attributed to Magneto-optical transitions within the Pt p and d bands.


Author(s):  
William Lafargue-Dit-Hauret ◽  
Camille Latouche ◽  
Bruno Viana ◽  
Mathieu Allix ◽  
Stéphane Jobic

This article reports for the first time an in-depth ab initio computational study on intrinsic point defects in Sr4Al14O25 that serves as host lattice for numerous phosphors. Defect Formation Enthalpies...


2020 ◽  
Author(s):  
Adam Balvanz ◽  
Jiaxing Qu ◽  
Sviatoslav Baranets ◽  
Elif Ertekin ◽  
Prashun Gorai ◽  
...  

Zintl phases, owing to their complex crystal structures and intricate chemical bonding, have recently been recognized as promising candidates for thermoelectric (TE) applications. Band engineering, including band convergence has been shown to be an effective way to enhance the thermoelectric performance of such materials. In this work, a series of emerging TE materials, the isostructural Zintl phases with the general formula <i>A</i><sub>2</sub>CdP<sub>2</sub> (<i>A</i> = Sr, Ba, Eu) are presented for the first time. Their structures, established from single-crystal X-ray diffraction methods, show them to crystallize with the orthorhombic Yb<sub>2</sub>CdSb<sub>2</sub> structure type, with first-principles calculations on phase stability confirming that Ba<sub>2</sub>CdP<sub>2</sub> and Sr<sub>2</sub>CdP<sub>2</sub> are thermodynamically stable. Computationally, it was found that both Ba<sub>2</sub>CdP<sub>2</sub> and Sr<sub>2</sub>CdP<sub>2</sub> have the potential to exhibit high <i>n</i>-type TE performance (0.6 and 0.7 relative to the <i>n</i>-type PbTe, a reference TE material). To optimize the TE performance, band engineering strategies, including isovalent substitution and cation mutations, were investigated. From the band engineering of Ba<sub>2</sub>CdP<sub>2</sub> via isovalent substitution of Sr on a single Ba site, leading to the quaternary composition SrBaCdP<sub>2</sub>, it can be suggested that increasing the conduction band valley degeneracy is an effective way to improve the <i>n</i>-type TE performance by three-fold. Moreover, first-principles defect calculations reveal that both Ba<sub>2</sub>CdP<sub>2</sub> and SrBaCdP<sub>2</sub> are <i>n</i>-type dopable, adding these compounds to a small list of rare <i>n</i>-type dopable Zintl phases. The band engineering strategies used in this work are equally applicable to other TE materials, either for optimization of existing TE materials or designing new materials with desired properties.


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