Properties Predicting of Transition Metal-Doped Anatase TiO2

2009 ◽  
Vol 620-622 ◽  
pp. 703-706 ◽  
Author(s):  
Xiao Guang Qu ◽  
Wen Xiu Liu ◽  
Jing Ma ◽  
Dan Ni Yu ◽  
Wen Bin Cao ◽  
...  
Keyword(s):  
Binding Energy ◽  
Transition Metals ◽  
Band Structure ◽  
Density Of States ◽  
Periodic System ◽  
First Principles ◽  
Anatase Tio2 ◽  
Calculated Binding Energy ◽  
Anatase Structure ◽  
Metal Doped

The binding energy of anatase TiO2, in which the Ti was substituted by other transition metals in the 4th, 5th and 6th periods of the periodic system of the elements, has been calculated by using first principles method. The doping limits of V, Cr, Zr, Nb, Mo and W are 61.5%, 39.7%, 88.2%, 100.0%, 65.0%, and 63.2%, respectively predicted by the calculated binding energy, while the doping limits of other transition metals are much lower. So, these transition metals can easily be doped into the anatase structure theoretically while it is difficult for the others. And the band structure and density of states (DOS) of V, Cr, Zr, Nb, Mo and W doped anatase TiO2 have also been calculated and analyzed.

EFFECT OF RELAXATION ON THE ENERGETICS AND STRUCTURE OF ANATASE TiO2 (101) SURFACE

2006 ◽  
Vol 13 (06) ◽  
pp. 825-831 ◽  
Author(s):  
XIN-GUO MA ◽  
CHAO-QUN TANG ◽  
XIAO-HUA YANG
Keyword(s):  
Band Structure ◽  
Density Of States ◽  
First Principles ◽  
Anatase Tio2 ◽  
Surface Relaxation ◽  
Slab Thickness ◽  
First Principles Calculations ◽  
Surface Charges ◽  
Good Agreement

A systematic study of unrelaxed and relaxed surface characters on the TiO 2 (101) surface has been carried out by first-principles calculations using plane-wave pseudopotential method. We find that O 2 c atoms have an inward relaxation of 0.012 Å and Ti 5 c atoms have an outward relaxation of 0.155 Å by taking a 24-layer slab with 5 Å vacuum width to consider the atomic relaxations, in good agreement with other theoretical values. The slab thickness has significant effect on the quality of band structure and density of states, and 24-layer slab is sufficient to present the electronic properties of TiO 2 (101) surface. Atomic relaxations result in a large transfer of surface charges from outermost layer to inner layer, and the surface bonds have a rehybridization, which makes the ionization reduce and the covalence increase; we believe that it causes the surface bond shorten. A fine analysis of band structure and density of states of the TiO 2 (101) surface shows that the surface relaxation induces the transformation from semi-metallic to semiconducting characteristic.

A STUDY ON STRAIN AFFECTING ELECTRONIC STRUCTURE OF WURTZITE ZnO BY FIRST PRINCIPLES

2009 ◽  
Vol 23 (19) ◽  
pp. 2339-2352 ◽  
Author(s):  
LI BIN SHI ◽  
SHUANG CHENG ◽  
RONG BING LI ◽  
LI KANG ◽  
JIAN WEI JIN ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Band Structure ◽  
Valence Band ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
Functional Theory ◽  
Electron Density Difference ◽  
Different Strains

Density of states and band structure of wurtzite ZnO are calculated by the CASTEP program based on density functional theory and plane-wave pseudopotential method. The calculations are carried out in axial and unaxial strains, respectively. The results of density of states in different strains show that the bottom of the conduction band is always dominated by Zn 4s, and the top of valence band is always dominated by O 2p. The variation of the band gap calculated from band structure is also discussed. In addition, p-d repulsion is used in investigating the variation of the top of the valence band in different strains and the results can be verified by electron density difference.

Effects of oxygen vacancy on 3d transition-metal doped anatase TiO2: First principles calculations

2016 ◽  
Vol 647 ◽  
pp. 36-41 ◽  
Author(s):  
Ya Fei Zhao ◽  
Can Li ◽  
Song Lu ◽  
Li Jin Yan ◽  
Yin Yan Gong ◽  
...  
Keyword(s):  
Transition Metal ◽  
Oxygen Vacancy ◽  
First Principles ◽  
Anatase Tio2 ◽  
First Principles Calculations ◽  
Metal Doped

Exploration on electronic and optical properties of two-dimensional GaN-doped with Be, Mg, Zn

2020 ◽  
Vol 34 (20) ◽  
pp. 2050195
Author(s):  
Gang Li ◽  
Lei Liu ◽  
Jian Tian
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Of States ◽  
First Principles ◽  
High Energy ◽  
Low Energy ◽  
Two Dimensional ◽  
Electronic And Optical Properties ◽  
Type Semiconductor ◽  
P Type

To explore the variation on p-type-doped two-dimensional GaN, we calculate electronic and optical properties of buckled two-dimensional GaN-doped with p-type doping elements including Be, Mg and Zn atom by using first-principles. The results indicate that doping process of two-dimensional GaN after Be is most easily compared with Mg- and Zn-doped models. Band of doped two-dimensional GaN moves toward high energy end and it becomes a p-type semiconductor from the results of band structure and density of states, which may be caused by orbitals hybridization from dopants. Band gap and work function of doped two-dimensional GaN are both declined, which is beneficial for escape of electrons. Analysis of optical properties shows that they are sensitive and adjustable in doped two-dimensional GaN. Doping of Be, Mg and Zn atoms would have an important effect on optical characteristics of two-dimensional GaN at low-energy region.

Electronic properties and lattice configurations of Au/CH3NH3PbI3 interface

2017 ◽  
Vol 31 (18) ◽  
pp. 1750199 ◽  
Author(s):  
F. J. Si ◽  
W. Hu ◽  
F. L. Tang ◽  
Y. W. Cheng ◽  
H. T. Xue
Keyword(s):  
Binding Energy ◽  
Charge Density ◽  
Density Of States ◽  
First Principles ◽  
Lattice Mismatch ◽  
Lattice Structure ◽  
Electronic States ◽  
Density Difference ◽  
First Principles Calculations ◽  
Charge Density Difference

The lattice structure, interface binding energy, density of states, charge density difference and Bader charges of Au (100)/CH3NH3PbI3 (MAPbI3) (100) interface were studied with the first-principles calculations. The lattice mismatch of the Au (100)/MAPbI3 (100) interface is 3.48%. The interface binding energy is −0.124 J/m2. There is a small amount of electronic states nearby the interface through analyzing the density of states of the interface. In addition, the atom orbital has hybridizations nearby the interface. Through analyzing charge density difference and Bader charges, it is found that there is obvious charge transfer at the interface.

scholarly journals First-Principles Study on Hydrogen Storage Performance of Transition Metal-Doped Zeolite Template Carbon

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 397 ◽  
Author(s):  
Han ◽  
Lv ◽  
Sun ◽  
Song
Keyword(s):  
Binding Energy ◽  
Transition Metal ◽  
Hydrogen Storage ◽  
First Principles ◽  
Hydrogen Adsorption ◽  
Storage Performance ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Metal Doped ◽  
Hydrogen Storage Performance

The hydrogen adsorption characteristics and mechanism of transition metal-doped zeolite template carbon (ZTC) as a novel porous material are studied by theoretical calculations employing first-principle all-electron atomic orbital method based on density functional theory. The stability of transition metal atoms (Sc, Ti, and V) decorated on zeolite template carbon is investigated by calculating the absorption binding energy. The adsorption configurations of the doped metal atom and adsorbed hydrogen are obtained from the energy functional minimization of first-principles calculations. The underlying mechanism for improving hydrogen storage performance of ZTC by doping transition metal atoms are explored through analyzing charge/spin populations of metal atoms in combination with the calculated results of hydrogen adsorption quantity and binding energy. To improve the hydrogen storage capability, the Sc, Ti, and V are individually introduced into the ZTC model according to the triplex axisymmetry. The hydrogen storage properties of ZTC decorated with different metal atoms are characterized by the adsorption energy and structure of several hydrogen atoms. The more energetically stable complex system with higher binding energy and adsorbing distance of hydrogen than lithium-doped ZTC can be achieved by doping Sc, Ti, V atoms in ZTC, which is expected to fulfill the substantial safe hydrogen storage by increasing hydrogen capacity with multi-sites doping of transition metal atoms. The present investigation provides a theoretical basis and predictions for the following experimental research and design of porous materials for hydrogen storage.

Electronic and optical properties of ZnSxSe1−x alloys

Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
Zhenbao Feng ◽  
Haiquan Hu ◽  
Shouxin Cui
Keyword(s):  
Experimental Data ◽  
Optical Properties ◽  
Band Structure ◽  
Density Of States ◽  
Absorption Edge ◽  
First Principles ◽  
Semiconductor Alloys ◽  
Electronic And Optical Properties ◽  
Spectral Peaks ◽  
Good Agreement

AbstractA series of calculations from first principles have been carried out to study structural, electronic, and optical properties of ZnSxSe1−x alloys. Our results show that the lattice constant scales linearly with sulfur composition. The imaginary parts of the dielectric function are calculated, which are in good agreement with the experimental data. We have also interpreted the origin of the spectral peaks on the basis of band structure and density of states. Additionally, we find that no bowing effect in the absorption edge is observed, unlike other II-VI semiconductor alloys.

scholarly journals First Principles Study of Thermoelectric Properties of Skutterudites: Ir4Sb12 and Ca0.04Ir4Sb12

2020 ◽  
Vol 6 (2) ◽  
pp. 1-9
Author(s):  
B. Bhattarai ◽  
T. Dahal ◽  
N. P. Adhikari
Keyword(s):  
Band Structure ◽  
Band Gap ◽  
Density Of States ◽  
First Principles ◽  
Figure Of Merit ◽  
Density Functional ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Metallic Behavior ◽  
Maximum Value

First – principles calculations to study thermal and electrical properties of pristine and calcium filled skutterudite Ir4Sb12 has been carried out. Density of states (DOS) and band-structure calculations are based on Density Functional Theory (DFT) within Generalized Gradient Approximation (GGA). Transport properties are calculated using BoltzTrap software packages. Volume optimization is carried out on the basis of Murnaghan equation of states. The optimized lattice parameter of pristine Ir4Sb12 is found to be 9.4243 Å and that of calcium filled Ir4Sb12 is found to be 9.4949 Å. Our calculation shows that pristine Ir4Sb12 is a p-type of semiconductor with a narrow PBE-GGA band gap of 0.25 eV. After filling calcium, the band gap is reduced to zero showing the metallic behavior of filled compound. Band structure, density of states, variations of electrical and thermal conductivities with temperature and Seebeck coefficient show that calcium filled Ir4Sb12 has a metallic character. At Fermi level, the maximum value of thermoelectric figure of merit of unfilled Ir4Sb12 compound at temperature 400K is found to be 0.5. At the same temperature thermoelectric figure of merit calcium filled Ca0.04Ir4Sb12 is found to be around 0.03. The maximum value of of Ca filled Ca0.04Ir4Sb12 at 1000K is computed around 0.1.

Effects of n-Type Dopants on Electronic Properties in 4H-SiC

2015 ◽  
Vol 645-646 ◽  
pp. 325-329
Author(s):  
Jin Long Tang ◽  
Jun Nan Zhong ◽  
Cai Wen
Keyword(s):  
Band Structure ◽  
Fermi Level ◽  
Band Gap ◽  
Electronic Properties ◽  
Density Of States ◽  
First Principles ◽  
Electronic Structures ◽  
Doping Concentration ◽  
Impurity Level ◽  
First Principles Calculations

Based on first-principles calculations, we have investigated atomic and electronic structures of 4H-SiC crystal doped by N, P and As elements as n-type dopants. We have obtained the bond lengths of the optimization system, as well as the impurity levels, the band structure and the density of states. The results show that the higher impurity level above the Fermi level is observed when 4H-SiC doped by N with concentration as 6.25% in these dopants, and the band gap of 4H-SiC decreases while the doping concentration or the atomic number of dopant increases.

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