Synergistic Effects on Band Gap-Narrowing in Titania by Codoping from First-Principles Calculations

First-principles calculations using the plane-wave pseudo-potential (PWPP) method based on the density functional theory (DFT) is employed to study the crystal structure, band gap, density of states of anatase TiO2 doped with gadolinium (Gd). The generalized gradient approximation (GGA) based on exchange-correlation energy optimization is employed to calculate them. The calculated results demonstrate that the mixing of gadolinium dopants induces states with original titanium 3d and oxygen 2p valence band attributes to the band gap narrowing. This can enhance the photocatalytic activity of anatase TiO2.

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Charged states and band-gap narrowing in codoped ZnO nanowires for enhanced photoelectrochemical responses: Density functional first-principles calculations

Physical Review B ◽

10.1103/physrevb.85.075402 ◽

2012 ◽

Vol 85 (7) ◽

Cited By ~ 15

Author(s):

Zhuo Xu ◽

Qing-Rong Zheng ◽

Gang Su

Keyword(s):

Band Gap ◽

First Principles ◽

Density Functional ◽

Zno Nanowires ◽

First Principles Calculations ◽

Band Gap Narrowing

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First-Principles Calculations on Pure and Y-Doped Anatase TiO2

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.562-565.1166 ◽

2013 ◽

Vol 562-565 ◽

pp. 1166-1170 ◽

Cited By ~ 1

Author(s):

Xiong Tang ◽

Lan Fang Yao ◽

Xin Pei Yan ◽

Jun Long Kang

Keyword(s):

Band Gap ◽

First Principles ◽

Density Functional ◽

Correlation Energy ◽

Partial Density ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

Calculation Results ◽

Band Gap Narrowing

Using the First principles calculations, the crystal structure, band gap, total and partial density of states (DOS) of anatase TiO2and anatase TiO2doped with Yttrium were calculated by a plane-wave pseudopotential (PWPP) method based on density functional theory (DFT). The generalized gradient approximation (GGA) based on exchange-correlation energy optimization was employed to calculate them. From the calculation results, the band gap of anatase TiO2and Y3+doped TiO2are about 2.15eV and 0.86eV. The calculated results demonstrated that the mixing of Yttrium (Y) dopants induces states with original titanium 3d and oxygen 2p valence band attributes to the band gap narrowing. This can enhance the photocatalytic activity of anatase TiO2.

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Synergistic effects on band gap-narrowing in titania by doping from first-principles calculations: density functional theory studies

MRS Proceedings ◽

10.1557/opl.2011.1079 ◽

2011 ◽

Vol 1352 ◽

Author(s):

Run Long ◽

Niall J. English

Keyword(s):

Visible Light ◽

Band Gap ◽

Density Functional ◽

Synergistic Effects ◽

Theoretical Calculations ◽

Binding Energies ◽

First Principles Calculations ◽

Functional Theory ◽

Band Gap Narrowing ◽

Formation Energies

ABSTRACTThe large intrinsic band gap in TiO2 has hindered severely its potential application for visible-light irradiation. We have used a passivated approach to modify the band edges of anatase-TiO2 by codoping of X (N, C) with transition metals (TM=W, Re, Os) to extend the absorption edge to longer visible-light wavelengths. It was found that all the codoped systems can narrow the band gap significantly; in particular, (N+W)-codoped systems could serve as remarkably better photocatalysts with both narrowing of the band gap and relatively smaller formation energies and larger binding energies than those of (C+TM) and (N+TM)-codoped systems. Our theoretical calculations help to rationalise experimental results and provide reasonably meaningful guides for experiment to develop more powerful visible-light photocatalysts.

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Locating impurity and defect levels in the host band gap by first-principles calculations: Pure and Ce3+-doped YAlO3

Optical Materials ◽

10.1016/j.optmat.2021.110843 ◽

2021 ◽

Vol 113 ◽

pp. 110843

Author(s):

M.G. Brik ◽

C.-G. Ma ◽

M. Piasecki ◽

A. Suchocki

Keyword(s):

Band Gap ◽

First Principles ◽

First Principles Calculations ◽

Impurity And Defect Levels ◽

Defect Levels

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Band-gap engineering of CdS, CdSe and ZnSe first-principles calculations

2016 International Renewable and Sustainable Energy Conference (IRSEC) ◽

10.1109/irsec.2016.7983969 ◽

2016 ◽

Author(s):

Rachida Lamouri ◽

El Mehdi Salmani ◽

Hamid Ez-zahraouy ◽

Abdelilah Benyoussef

Keyword(s):

Band Gap ◽

First Principles ◽

First Principles Calculations ◽

Band Gap Engineering

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Strain-induced semimetal-to-semiconductor transition and indirect-to-direct band gap transition in monolayer 1T-TiS2

RSC Advances ◽

10.1039/c5ra16877e ◽

2015 ◽

Vol 5 (102) ◽

pp. 83876-83879 ◽

Cited By ~ 23

Author(s):

Chengyong Xu ◽

Paul A. Brown ◽

Kevin L. Shuford

Keyword(s):

Band Gap ◽

Electronic Properties ◽

Plane Strain ◽

Material Properties ◽

First Principles ◽

Tensile Strain ◽

First Principles Calculations ◽

Direct Band Gap ◽

Direct Band ◽

Uniform Plane

We have investigated the effect of uniform plane strain on the electronic properties of monolayer 1T-TiS2using first-principles calculations. With the appropriate tensile strain, the material properties can be transformed from a semimetal to a direct band gap semiconductor.

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First-Principles Study on the Stabilities, Electronic and Optical Properties of GexSn1-xSe Alloys

Nanomaterials ◽

10.3390/nano8110876 ◽

2018 ◽

Vol 8 (11) ◽

pp. 876 ◽

Cited By ~ 1

Author(s):

Qi Qian ◽

Lei Peng ◽

Yu Cui ◽

Liping Sun ◽

Jinyan Du ◽

...

Keyword(s):

Optical Properties ◽

Solar Cells ◽

Band Gap ◽

Electronic Properties ◽

First Principles ◽

Future Application ◽

First Principles Calculations ◽

Electronic And Optical Properties ◽

Direct Bandgap ◽

The Future

We systematically study, by using first-principles calculations, stabilities, electronic properties, and optical properties of GexSn1-xSe alloy made of SnSe and GeSe monolayers with different Ge concentrations x = 0.0, 0.25, 0.5, 0.75, and 1.0. Our results show that the critical solubility temperature of the alloy is around 580 K. With the increase of Ge concentration, band gap of the alloy increases nonlinearly and ranges from 0.92 to 1.13 eV at the PBE level and 1.39 to 1.59 eV at the HSE06 level. When the Ge concentration x is more than 0.5, the alloy changes into a direct bandgap semiconductor; the band gap ranges from 1.06 to 1.13 eV at the PBE level and 1.50 to 1.59 eV at the HSE06 level, which falls within the range of the optimum band gap for solar cells. Further optical calculations verify that, through alloying, the optical properties can be improved by subtle controlling the compositions. Since GexSn1-xSe alloys with different compositions have been successfully fabricated in experiments, we hope these insights will contribute to the future application in optoelectronics.

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First-Principles Calculations of Titanium Dopants in Alumina

Materials Science Forum ◽

10.4028/www.scientific.net/msf.475-479.3095 ◽

2005 ◽

Vol 475-479 ◽

pp. 3095-3098

Author(s):

Katsuyuki Matsunaga ◽

Teruyasu Mizoguchi ◽

Atsutomo Nakamura ◽

Takahisa Yamamoto ◽

Yuichi Ikuhara

Keyword(s):

Band Gap ◽

First Principles ◽

Electronic Structures ◽

First Principles Calculations ◽

Pseudopotential Calculations ◽

Formation Energies

First-principles pseudopotential calculations were performed to investigate atomic and electronic structures of titanium (Ti) dopants in alumina (Al2O3). It was found that a substitutional Ti3+ defect induced an extra level occupied by one electron within the band gap of Al2O3. When two or more substitutional Ti3+ defects were located closely to each other, the defect-induced levels exhibited strong bonding interactions, and their formation energies decreased with increasing numbers of Ti3+ defects. This indicates that association and clustering of substitutional Ti3+ defects in Al2O3 can take place due to the interaction of the defect-induced levels.

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