scholarly journals Engineering Electronic Structure and Band Alignment of 2D Mg(OH)2 via Anion Doping for Photocatalytic Applications

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2640
Author(s):  
Shunnian Wu ◽  
Hasanthi L. Senevirathna ◽  
P. Vishakha T. Weerasinghe ◽  
Ping Wu
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Band Gap ◽  
Water Splitting ◽  
Gas Sensing ◽  
Oxidation Potential ◽  
Band Alignment ◽  
Anion Doping ◽  
Dopant Atoms ◽  
Photocatalytic Applications

The wide bandgap of 2D Mg(OH)2 inhibits its applications in visible-light photocatalytic applications. Besides, its mismatched band alignment to the redox potential of O2/H2O, brings about low efficacy of water-splitting performance. Therefore, to release the powder of 2D Mg(OH)2 in photocatalytic research, we explore anion doping strategies to engineer its electronic structure. Here, anion doping effects on electronic properties of 2D Mg(OH)2 are investigated by using DFT calculations for seven dopants (F, Cl, S, N, P, SO4, and PO4). We found (1) S, N and P doping remarkably reduces its band gap from 4.82 eV to 3.86 eV, 3.79 eV and 2.69 eV, respectively; (2) the band gap reduction is induced by the electron transfer to the dopant atoms; (3) F, Cl, SO4, and PO4 doping shifts its valence band to be lower than the oxidation potential of O2/H2O to render its band structure appropriate for photocatalytic water splitting. These results suggest that not only electrical conductivity of 2D Mg(OH)2 can be increased but also their band structure be aligned by using the proposed anion doping strategy. These results enable a new photocatalytic materials design approach while offering exciting possibilities in applications of high-current electrolysis, chemical gas sensing, and photocatalysis.

scholarly journals Strain-tunable band alignment and band gap of GaSe/WTe2 heterojunction for water splitting and light-emitting

2021 ◽  
pp. 104605
Author(s):  
Qingyi Feng ◽  
Hongxiang Deng ◽  
Hongdong Yang ◽  
Shasha Ke ◽  
Haifeng Lv ◽  
...  
Keyword(s):  
Band Gap ◽  
Water Splitting ◽  
Band Alignment ◽  
Light Emitting

CHANGES INDUCED IN THE SURFACE ELECTRONIC STRUCTURE OF Be(0001) AFTER Si ADSORPTION

2002 ◽  
Vol 09 (02) ◽  
pp. 687-691
Author(s):  
L. I. JOHANSSON ◽  
C. VIROJANADARA ◽  
T. BALASUBRAMANIAN
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Band Gap ◽  
Electronic Properties ◽  
Surface State ◽  
Core Level ◽  
Clean Surface ◽  
Core Level Spectrum ◽  
Surface Band ◽  
Surface Electronic Structure

A study of effects induced in the Be 1s core level spectrum and in the surface band structure after Si adsorption on Be(0001) is reported. The changes in the Be 1s spectrum are quite dramatic. The number of resolvable surface components and the magnitude of the shifts do decrease and the relative intensities of the shifted components are drastically different compared to the clean surface. The surface band structure is also strongly affected after Si adsorption and annealing. At [Formula: see text] the surface state is found to move down from 2.8 to 4.1 eV. The band also splits at around 0.5 Å-1 along both the [Formula: see text] and [Formula: see text] directions. At [Formula: see text] and beyond [Formula: see text] only one surface state is observed in the band gap instead of the two for the clean surface. Our findings indicate that a fairly small amount of Si in the outer atomic layers strongly modifies the electronic properties of these layers.

Energy band alignment at the heterointerface between a nanostructured TiO2 layer and Au22(SG)18 clusters: relevance to metal-cluster-sensitized solar cells

Nanoscale ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 175-184
Author(s):  
Liudmila L. Larina ◽  
Oleksii Omelianovych ◽  
Van-Duong Dao ◽  
Kyunglim Pyo ◽  
Dongil Lee ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Solar Cells ◽  
Band Structure ◽  
Electronic Band Structure ◽  
Metal Cluster ◽  
Band Alignment ◽  
Tio2 Layer ◽  
Electronic Band ◽  
Xps Study ◽  
Sensitized Solar Cells

XPS study of the electronic structure of the Au22(SG)18 clusters and their interface with TiO2 reveals that tailoring of the electronic band structure at the interface can be exploited to increase the efficiency of metal-cluster-sensitized solar cells.

Atomic and Electronic Structure of LaAlO3 and LaAlO3:Mg from First-Principles Calculations

2009 ◽  
Vol 79-82 ◽  
pp. 1257-1260
Author(s):  
Li Guan ◽  
Li Tao Jin ◽  
Wei Zhang ◽  
Qiang Li ◽  
Jian Xin Guo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Band Gap ◽  
Density Functional ◽  
Lattice Structure ◽  
Cell Structure ◽  
Functional Theory ◽  
Super Cell ◽  
Direct Band ◽  
Experimental Values

In the present paper, the lattice structure, band structure and density of state of LaAlO3 and LaAlO3:Mg are calculated by first-principle method based on density functional theory. Firstly, we select the different cutoff energy and k-point grid in the calculations, and obtain the most stable geometry structure of single crystal LaAlO3. The calculated lattice parameters are a=b=5.441 Å, c=13.266 Å, which matches with experimental values. To deeply understand the electronic structure of LaAlO3, a 2×1×1 super-cell structure is established and the doping concentration of Mg at Al sites is 25%. From the band structure and density of states, it can be seen that LaAlO3 has a direct band gap Eg=3.6 eV. However, LaAlO3:Mg has a larger band gap Eg=3.89 eV and the Fermi level enters into the valence band, which indicates the holes are introduced. The calculated results show that the conductivity of LaAlO3:Mg is better than pure LaAlO3, which is in good agreement with experimental results.

A hybrid DFT based investigation of the photocatalytic activity of cation–anion codoped SrTiO3 for water splitting under visible light

2014 ◽  
Vol 16 (44) ◽  
pp. 24527-24535 ◽  
Author(s):  
Brindaban Modak ◽  
K. Srinivasu ◽  
Swapan K. Ghosh
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Water Splitting ◽  
Band Alignment ◽  
Trapping Center

The effect of cation (Mo or W) and anion (N) codoping in different proportion has been explored to improve the photocatalytic activity of SrTiO3 under visible light. Codoping in 1 : 2 ratio has been found to be more effective due to reduction in band gap without introducing local trapping center and also for maintaining appropriate band alignment.

scholarly journals First Principle Calculation of Electronic, Optical Properties and Photocatalytic Potential of CuO Surfaces

2016 ◽  
Vol 1 ◽  
Author(s):  
Faozan Ahmad
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Band Gap ◽  
Water Splitting ◽  
Co2 Reduction ◽  
Band Edge ◽  
Semiconductor Surface ◽  
First Principle Calculation ◽  
Stable Surface ◽  
Input Parameters

<p class="TTPKeywords">We have performed DFT calculations of electronic structure, optical properties and photocatalytic potential of the low-index surfaces of CuO. Photocatalytic reaction on the surface of semiconductor requires the appropriate band edge of the semiconductor surface to drive redox reactions. The calculation begins with the electronic structure of bulk system; it aims to determine realistic input parameters and band gap prediction. CuO is an antiferromagnetic material with strong electronic correlations, so that we have applied DFT + U calculation with spin polarized approach, beside it, we also have used GW approximation to get band gap correction. Based on the input parameters obtained, then we calculate surface energy, work function and band edge of the surfaces based on a framework developed by Bendavid et al (J. Phys. Chem. B, 117, 15750-15760) and then they are aligned with redox potential needed for water splitting and CO<sub>2</sub> reduction. Based on the calculations result can be concluded that not all of low-index CuO have appropriate band edge to push reaction of water splitting and CO2 reduction, only the surface CuO(111) and CuO(011) which meets the required band edge. Fortunately, based on the formation energy, CuO(111) and CuO(011) is the most stable surface. The last we calculate electronic structure and optical properties (dielectric function) of low-index surface of CuO, in order to determine the surface state of the most stable surface of CuO.</p>

Electronic Structure and Thermoelectric Properties of AxMo3Sb5Te2

2003 ◽  
Vol 793 ◽  
Author(s):  
Navid Soheilnia ◽  
Holger Kleinke
Keyword(s):  
Thermal Conductivity ◽  
Electronic Structure ◽  
Band Structure ◽  
Band Gap ◽  
Thermoelectric Properties ◽  
Gap Size ◽  
Formula Unit ◽  
Chemically Modified ◽  
Thermoelectric Energy ◽  
Attractive Candidate

ABSTRACTMo3Sb7 may be chemically modified to become semiconducting by replacing two Sb atoms with two Te atoms (per formula unit). This material may be an attractive candidate for the thermoelectric energy conversion, as its thermal conductivity may be lowered by creating the rattling effect upon intercalation of small cations, and its band structure may be tailored, i.e. the band gap size modified. The higher the Te content and the higher the cation amount, the smaller is the band gap, which can virtually reach any value below 0.5 eV.

First-Principles Study on Electronic Structure of 15R-SiC Polytypes

2014 ◽  
Vol 971-973 ◽  
pp. 77-80 ◽  
Author(s):  
Fu Chun Zhang ◽  
Ying Gao ◽  
Hong Wei Cui ◽  
Xing Xiang Ruan ◽  
Wei Hu Zhang
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Charge Density ◽  
Band Gap ◽  
Density Functional ◽  
Covalent Bond ◽  
Lattice Parameter ◽  
Pseudopotential Approach ◽  
Structure Density ◽  
Indirect Band Gap

To study the geometrical and electronic structure of 15R-SiC polytypes, the lattice parameter, band structure, density of states (DOS) and charge density of 15R-SiC are calculated by using density functional theory based on the plane wave pseudopotential approach, and electronic structure and ground properties of 15R-SiC are investigated by the calculated band structure and DOS, the results show that 15R-SiC is an indirect band gap semiconductor, with calculated indirect band gap width being 2.16 eV and band gap dependent on Si 3p and C 2p states. While charge density results show that Si-C bond is a hybrid bond semiconductor strong in covalent bond and weak in ionicity, characterized by intense sp3 hybrid characteristics, which is in accordance with the experimental results. The above mentioned results are considered as theoretical reference for design and application of SiC polytype materials.

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