scholarly journals Effect of H2O Molecule Adsorption on the Electronic Structure and Optical Properties of the CsI(Na) Crystal

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1720
Author(s):  
Fang Liu ◽  
Hao Zheng ◽  
Tianze Jiang ◽  
Bin Liu ◽  
Jianming Zhang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Gamma Ray ◽  
Crystal Surface ◽  
Emission Spectra ◽  
Generalized Gradient ◽  
Molecule Adsorption ◽  
Luminescence Efficiency ◽  
Calculation Results ◽  
Structure Density

We investigated H2O molecule adsorption that had an effect on the luminescence properties of the CsI(Na) crystal using experiments and first-principle calculations. We measured the emission spectra of the CsI(Na) crystal at different exposure times under gamma ray excitation. The experimental results showed that the energy resolution of the CsI(Na) crystal was worse when the crystal surface adsorbed more H2O molecules, and the crystal surface deliquescence decreased the luminescence efficiency of the CsI(Na) crystal. We studied the band structure, density of states, and optical properties changes caused by H2O molecule adsorption on the CsI(Na) (010) surface. The generalized gradient approximation (GGA) was used to describe the exchange and correlation potential between the electrons. Our calculation results showed that the band gap width of the CsI(Na) (010) surface decreased after adsorbing H2O molecules, while three new peaks appeared in the valence band, and the absorption coefficient decreased from 90,000 cm−1 to 65,000 cm−1, and the reflection coefficient decreased from 0.195 to 0.105. Further, the absorption coefficient was reduced by at least 25% because of H2O molecule adsorption, which led to the luminescence degradation of the CsI(Na) crystal.

Electronic Structure and Optical Properties of SrTi0.5Zr0.5O3

2013 ◽  
Vol 846-847 ◽  
pp. 1919-1922
Author(s):  
Hong Liang Pan ◽  
Teng Li ◽  
Shi Liang Yang ◽  
Yi Ming Liu
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Energy Band ◽  
Electronic Energy ◽  
Energy Band Structure ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation ◽  
Structure Density ◽  
Pseudo Potential ◽  
Electronic Energy Band

The electronic-energy band structure and optical properties of SrTi0.5Zr0.5O3are calculated by the pseudo-potential plane wave (PP-PW) mehod with the generalized gradient approximation (GGA). The energy band structure, density of states (DOS) are obtained. The optical properties including the dielectric function, reflectivity, absorption spectrum, extinction coefficient, energy-loss spectrum and refractive index are also discussed.

Electronic Structure and Optical Properties of BaTi0.75Nd0.25O3

2013 ◽  
Vol 846-847 ◽  
pp. 1923-1926
Author(s):  
Shi Liang Yang ◽  
Hong Liang Pan ◽  
Teng Li ◽  
Yi Ming Liu
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Energy Band ◽  
Electronic Energy ◽  
Energy Band Structure ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation ◽  
Structure Density ◽  
Pseudo Potential ◽  
Electronic Energy Band

The electronic-energy band structure and optical properties of BaTi0.75Nd0.25O3are calculated by the pseudo-potential plane wave (PP-PW) mehod with the generalized gradient approximation (GGA). The energy band structure, density of states (DOS) are obtained. The optical properties including the dielectric function, reflectivity, absorption spectrum, extinction coefficient, energy-loss spectrum and refractive index are also discussed.

Crystal Structure and Photoelectric Property of Thin-Film Solar Cell Materials Cd1-xZnxS

2012 ◽  
Vol 512-515 ◽  
pp. 23-29
Author(s):  
Fu Cheng Wan ◽  
Wen Jiang Lu ◽  
Fu Ling Tang ◽  
Yu Dong Feng ◽  
Zhi Min Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Electrical Properties ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Density Functional ◽  
Doping Concentration ◽  
Optical Absorption Coefficient ◽  
Generalized Gradient ◽  
Rate Of Increase

Based on density functional theory (DFT) within the framework of the generalized gradient approximation method, we have studied the Cd1-xZnxS sphalerite crystal structure and optical properties. We calculated electronic and optical properties of Cd1-xZnxS at the doping concentration x = 0, 0.25, 0.50, 0.75, 1.0. Optical properties (reflectivity, absorption coefficient, refractive index, dielectric function) and the electrical properties (band structure, electron density, etc.) are obtained including Zn-doing effects on the crystal structure, optical properties and electrical properties. With the increase of doping concentration x, the lattice parameter reduces from 0.5910 nm to 0.5409 nm; as a direct wide band gap semiconductor, its band gap increased from 1.15 to 2.22. Optical absorption coefficient increases with the increase of doping concentration, but the rate of increase is relatively small.

New Red-Emitting Phosphor La2Zr3(MoO4)9:Eu3+ and the Influence of Host Absorption on its Luminescence Efficiency

2015 ◽  
Vol 68 (11) ◽  
pp. 1727 ◽  
Author(s):  
Florian Baur ◽  
Thomas Jüstel
Keyword(s):  
Optical Properties ◽  
Charge Transfer ◽  
Absorption Band ◽  
Emission Spectra ◽  
Temperature Dependent ◽  
Broad Absorption ◽  
Broad Absorption Band ◽  
Transfer Processes ◽  
Luminescence Efficiency ◽  
Red Emitting Phosphor

This work investigates the optical properties of Eu3+-activated La2Zr3(MoO4)9. A series of solid solutions with Eu3+ concentrations in the range of 0–100 % were prepared by conventional high temperature solid-state synthesis. An unusual change in the lattice parameters was observed. The phosphor exhibits a broad absorption band in the UV spectral region, and measurements on the non-doped material at 100 K were conducted to elucidate the nature of the absorption band. As demonstrated, Mo6+ charge transfer absorption negatively influences the luminescence efficiency of the phosphor. The temperature-dependent emission spectra revealed that the emission intensity exhibits a bi-sigmoidal temperature dependence. This behaviour results from competing absorption via Mo6+ charge transfer processes, which strongly decrease the efficiency of the phosphor. For application purposes, it is therefore advisable to choose materials that do not exhibit host absorption in the spectral range where excitation is expected.

First-Principles Study of Structural, Electronic and Optical Properties in BaTi0.5Ni0.5O3

2013 ◽  
Vol 834-836 ◽  
pp. 268-271
Author(s):  
Hong Liang Pan ◽  
Shi Liang Yang ◽  
Teng Li
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
First Principles ◽  
Energy Band Structure ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Generalized Gradient Approximation ◽  
Structure Density ◽  
Pseudo Potential

The pseudo-potential plane wave (PP-PW) mehod with the generalized gradient approximation (GGA) is applied to study the electronic and optical properties of BaTi0.5Ni0.5O3. The energy band structure, density of states (DOS) are obtained. The optical properties including the dielectric function, reflectivity, absorption spectrum, extinction coefficient, energy-loss spectrum and refractive index are also calculated and analyzed in detail.

DFT-BASEDAB INITIOSTUDY OF THE ELECTRONIC AND OPTICAL PROPERTIES OF CESIUM BASED FLUORO-PEROVSKITECsMF3(M = CaANDSr)

2012 ◽  
Vol 26 (32) ◽  
pp. 1250199 ◽  
Author(s):  
M. HARMEL ◽  
H. KHACHAI ◽  
M. AMERI ◽  
R. KHENATA ◽  
N. BAKI ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Theoretical Data ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Structure Density

Density functional theory (DFT) is performed to study the structural, electronic and optical properties of cubic fluoroperovskite AMF3( A = Cs ; M = Ca and Sr ) compounds. The calculations are based on the total-energy calculations within the full-potential linearized augmented plane wave (FP-LAPW) method. The exchange-correlation potential is treated by local density approximation (LDA) and generalized gradient approximation (GGA). The structural properties, including lattice constants, bulk modulus and their pressure derivatives are in very good agreement with the available experimental and theoretical data. The calculations of the electronic band structure, density of states and charge density reveal that compounds are both ionic insulators. The optical properties (namely: the real and the imaginary parts of the dielectric function ε(ω), the refractive index n(ω) and the extinction coefficient k(ω)) were calculated for radiation up to 40.0 eV.

Magnetic behavior of Mn-doped silicon carbide nanosheet

2017 ◽  
Vol 31 (22) ◽  
pp. 1750163 ◽  
Author(s):  
M. Houmad ◽  
O. Dakir ◽  
H. Benzidi ◽  
O. Mounkachi ◽  
A. El Kenz ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Density Functional ◽  
Visible Region ◽  
Magnetic Behavior ◽  
Ferromagnetic Behavior ◽  
Full Potential ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Linearized Augmented Plane Wave

Magnetic and optical properties of (Mn, Fe)-doped SiC nanosheet (NS) are investigated using first principle calculations based on Density Functional Theory (DFT) within the Full Potential Linearized Augmented Plane Wave (FP-LAPW) method. The Generalized Gradient Approximation (GGA) shows that doping SiC NS by Mn has a half-metal ferromagnetic behavior when one Si atom is replaced by Mn or Fe. We also study the effect of (Mn, Fe) doping on optical properties of SiC NS such as absorption coefficient and optical reflectivity as function of energy. We found that doping SiC NS increases the absorption coefficient, the optical conductivity and the reflectivity in the visible region.

Electronic Structure and Optical Properties of InN: A First-Principles Study

2013 ◽  
Vol 760-762 ◽  
pp. 425-428
Author(s):  
Wei Hua Wang ◽  
Guo Zhong Zhao
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Potential Method ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structure Density ◽  
Pseudo Potential

The electronic properties and the optical properties of wurtzite InN are studied by the first-principles calculations based on the density functional theory. The calculations are based on the Generalized-Gradient Approximation (GGA) and implemented in Plane Wave Self-Consist Field (PWSCF). The optical properties of InN are investigated by the pseudo-potential method with PBEsol-GGA within the WIEN2K program. Band structure, density of states and dielectric functions are calculated detailedly. The energy transitions are observed and compared existing data at critical points. Moreover the new peak in between the region 12 eV to 14 eV should be due to transitions from the In-5p states to the N-2s states.

Ab initio calculation on the Optical Properties of AA- Stacked two dimensional Graphene, Silicene, Germanene, and Stanene

2018 ◽  
Vol 1 (1) ◽  
pp. 46-50
Author(s):  
Rita John ◽  
Benita Merlin
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Complex Refractive Index ◽  
Single Layer ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Wide Range ◽  
Optical Region

In this study, we have analyzed the electronic band structure and optical properties of AA-stacked bilayer graphene and its 2D analogues and compared the results with single layers. The calculations have been done using Density Functional Theory with Generalized Gradient Approximation as exchange correlation potential as in CASTEP. The study on electronic band structure shows the splitting of valence and conduction bands. A band gap of 0.342eV in graphene and an infinitesimally small gap in other 2D materials are generated. Similar to a single layer, AA-stacked bilayer materials also exhibit excellent optical properties throughout the optical region from infrared to ultraviolet. Optical properties are studied along both parallel (||) and perpendicular ( ) polarization directions. The complex dielectric function (ε) and the complex refractive index (N) are calculated. The calculated values of ε and N enable us to analyze optical absorption, reflectivity, conductivity, and the electron loss function. Inferences from the study of optical properties are presented. In general the optical properties are found to be enhanced compared to its corresponding single layer. The further study brings out greater inferences towards their direct application in the optical industry through a wide range of the optical spectrum.

scholarly journals Comparative Study on Electronic Structure and Optical Properties of α-Fe2O3, Ag/α-Fe2O3 and S/α-Fe2O3

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 424
Author(s):  
Cuihua Zhao ◽  
Baishi Li ◽  
Xi Zhou ◽  
Jianhua Chen ◽  
Hongqun Tang
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Electronic Structures ◽  
Density Functional ◽  
Peak Strength ◽  
Visible Range ◽  
High Symmetry ◽  
Functional Theory ◽  
Optical Absorption Peak ◽  
Calculation Results

The electronic structures and optical properties of pure, Ag-doped and S-doped α-Fe2O3 were studied using density functional theory (DFT). The calculation results show that the structure of α-Fe2O3 crystal changes after Ag and S doping, which leads to the different points of the high symmetry of Ag-doped and S-doped α-Fe2O3 with that of pure α-Fe2O3 in the energy band, as well as different Brillouin paths. In addition, the band gap of α-Fe2O3 becomes smaller after Ag and S doping, and the optical absorption peak shifts slightly toward the short wavelength, with the increased peak strength of S/α-Fe2O3 and the decreased peak strength of Ag/α-Fe2O3. However, the optical absorption in the visible range is enhanced after Ag and S doping compared with that of pure α-Fe2O3 when the wavelength is greater than 380 nm, and the optical absorption of S-doped α-Fe2O3 is stronger than that of Ag-doped α-Fe2O3.

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