Band alignment and charge transfer predictions of ZnO/ZnX (X = S, Se or Te) interfaces applied to solar cells: a PBE+U theoretical study

2018 ◽  
Vol 20 (7) ◽  
pp. 4953-4961 ◽  
Author(s):  
Efracio Mamani Flores ◽  
Rogério Almeida Gouvea ◽  
Maurício Jeomar Piotrowski ◽  
Mário Lucio Moreira
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
First Principles ◽  
Theoretical Study ◽  
Band Alignment ◽  
First Principles Calculations

We performed first-principles calculations within PBE and PBE+U approximations to study ZnO and ZnX bulk systems and ZnO/ZnX interfaces (X = S, Se or Te), to the better comprehension of charge transference through the interface.

scholarly journals Unraveling energy and charge transfer in type-II van der Waals heterostructures

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Junyi Liu ◽  
Zi Li ◽  
Xu Zhang ◽  
Gang Lu
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
First Principles ◽  
Rational Design ◽  
Van Der Waals ◽  
Band Alignment ◽  
Type Ii ◽  
First Principles Calculations ◽  
Comprehensive Picture ◽  
Excitonic Effect

AbstractRecent experiments observed significant energy transfer in type-II van der Waals (vdW) heterostructures, such as WS2/MoSe2, which is surprising due to their staggered band alignment and weak spectral overlap. In this work, we carry out first-principles calculations to shed light on energy and charge transfer in WS2/MoSe2 heterostructure. Incorporating excitonic effect in nonadiabatic electronic dynamics, our first-principles calculations uncover a two-step process in competing energy and charge transfer, unravel their relative efficiencies and explore the means to control their competition. While both Dexter and Förster mechanisms can be responsible for energy transfer, they are shown to operate at different conditions. The excitonic effect is revealed to drive ultrafast energy and charge transfer in type-II WS2/MoSe2 heterostructure. Our work provides a comprehensive picture of exciton dynamics in vdW heterostructures and paves the way for rational design of novel vdW heterostructures for optoelectronic and photovoltaic applications.

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

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 876 ◽  
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.

FIRST PRINCIPLES DENSITY FUNCTIONAL INVESTIGATION OF SUPPORTED TUNGSTEN CLUSTER (Wn; n = 1 TO 6) ON ANCHORED GRAPHITE (0001) SURFACE

2013 ◽  
Vol 02 (03n04) ◽  
pp. 1350015
Author(s):  
SONALI BARMAN ◽  
G. P. DAS ◽  
Y. KAWAZOE
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Metal Clusters ◽  
Theoretical Study ◽  
First Principles Calculations ◽  
Novel Technique ◽  
Defect Site ◽  
Positive Ions ◽  
Spin Polarized ◽  
Functional Investigation

Size-selected Wn clusters can be deposited firmly on a graphite (0001) surface using a novel technique, where the positive ions (of the same metal atom species) embedded on the graphite surface by ion implantation, act as anchors. The size selected metal clusters can then soft land on this anchored surface m [Hayakawa et al., 2009]. We have carried out a systematic theoretical study of the adsorption of Wn (n = 1-6) clusters on anchored graphite (0001) surface, using state-of-art spin-polarized density functional approach. In our first-principles calculations, the graphite (0001) surface has been suitably modeled as a slab separated by large vacuum layers. Wn clusters bond on clean graphite (0001) surface with a rather weak Van-der-Waals interaction. However, on the anchored graphite (0001) surface, the Wn clusters get absorbed at the defect site with a much larger adsorption energy. We report here the results of our first-principles investigation of this supported Wn cluster system, along with their reactivity trend as a function of the cluster size (n).

scholarly journals A theoretical study of blue phosphorene nanoribbons based on first-principles calculations

2014 ◽  
Vol 116 (7) ◽  
pp. 073704 ◽  
Author(s):  
Jiafeng Xie ◽  
M. S. Si ◽  
D. Z. Yang ◽  
Z. Y. Zhang ◽  
D. S. Xue
Keyword(s):  
First Principles ◽  
Theoretical Study ◽  
First Principles Calculations ◽  
Blue Phosphorene

scholarly journals Rich p -type-doping phenomena in boron-substituted silicene systems

2020 ◽  
Vol 7 (12) ◽  
pp. 200723
Author(s):  
Hai Duong Pham ◽  
Wu-Pei Su ◽  
Thi Dieu Hien Nguyen ◽  
Ngoc Thanh Thuy Tran ◽  
Ming-Fa Lin
Keyword(s):  
Charge Transfer ◽  
Fermi Level ◽  
Charge Density ◽  
Electronic Properties ◽  
First Principles ◽  
Chemical Environment ◽  
First Principles Calculations ◽  
Density Distributions ◽  
Essential Properties ◽  
P Type

The essential properties of monolayer silicene greatly enriched by boron substitutions are thoroughly explored through first-principles calculations. Delicate analyses are conducted on the highly non-uniform Moire superlattices, atom-dominated band structures, charge density distributions and atom- and orbital-decomposed van Hove singularities. The hybridized 2 p z –3 p z and [2s, 2 p x , 2 p y ]–[3s, 3 p x , 3 p y ] bondings, with orthogonal relations, are obtained from the developed theoretical framework. The red-shifted Fermi level and the modified Dirac cones/ π bands/ σ bands are clearly identified under various concentrations and configurations of boron-guest atoms. Our results demonstrate that the charge transfer leads to the non-uniform chemical environment that creates diverse electronic properties.

scholarly journals First-Principles Calculations of High-Pressure Physical Properties of Ti0.5Ta0.5 Alloy

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 796
Author(s):  
Fang Yu ◽  
Yu Liu
Keyword(s):  
High Pressure ◽  
Physical Properties ◽  
First Principles ◽  
Theoretical Study ◽  
Applied Pressure ◽  
Lattice Parameter ◽  
Physical Parameters ◽  
First Principles Calculations ◽  
Analysis Method ◽  
Metallic Bond

In this paper, an in-depth theoretical study on some physical properties of Ti0.5Ta0.5 alloy with systematic symmetry under high pressure is conducted via first-principles calculations, and relevant physical parameters are calculated. The results demonstrate that the calculated parameters, including lattice parameter, elastic constants, and elastic moduli, fit well with available theoretical and experimental data when the Ti0.5Ta0.5 alloy is under T = 0 and P = 0 , indicating that the theoretical analysis method can effectively predict the physical properties of the Ti0.5Ta0.5 alloy. The microstructure and macroscopic physical properties of the alloy cannot be destroyed as the applied pressure ranges from 0 to 50GPa, but the phase transition of crystal structure may occur in the Ti0.5Ta0.5 alloy if the applied pressure continues to increase according to the TDOS curves and charge density diagram. The value of Young’s and shear modulus is maximized at P = 25   GPa . The anisotropy factors A ( 100 ) [ 001 ] and A ( 110 ) [ 001 ] are equal to 1, suggesting the Ti0.5Ta0.5 alloy is an isotropic material at 28 GPa, and the metallic bond is strengthened under high pressure. The present results provide helpful insights into the physical properties of Ti0.5Ta0.5 alloy.

scholarly journals Ab-Initio Study of the Electronic and Magnetic Properties of Boron- and Nitrogen-Doped Penta-Graphene

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 816 ◽  
Author(s):  
Chao Zhang ◽  
Yu Cao ◽  
Xing Dai ◽  
Xian-Yong Ding ◽  
Leilei Chen ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Charge Transfer ◽  
First Principles ◽  
Magnetic Moments ◽  
First Principles Calculations ◽  
Electronic Band ◽  
Magnetic Devices ◽  
Spin Polarized ◽  
Electronic Band Gap ◽  
Transfer Mechanisms

First-principles calculations were performed to investigate the effects of boron/nitrogen dopant on the geometry, electronic structure and magnetic properties of the penta-graphene system. It was found that the electronic band gap of penta-graphene could be tuned and varied between 1.88 and 2.12 eV depending on the type and location of the substitution. Moreover, the introduction of dopant could cause spin polarization and lead to the emergence of local magnetic moments. The main origin of the magnetic moment was analyzed and discussed by the examination of the spin-polarized charge density. Furthermore, the direction of charge transfer between the dopant and host atoms could be attributed to the competition between the charge polarization and the atomic electronegativity. Two charge-transfer mechanisms worked together to determine which atoms obtained electrons. These results provide the possibility of modifying penta-graphene by doping, making it suitable for future applications in the field of optoelectronic and magnetic devices.

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