Optical properties of single crystalline copper iodide with native defects: Experimental and density functional theoretical investigation

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.

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First principles calculation of structural, electronic and optical properties of (001) and (110) growth axis (InN)/(GaN)n superlattices

Revista Mexicana de Física ◽

10.31349/revmexfis.67.7 ◽

2021 ◽

Vol 67 (1 Jan-Feb) ◽

pp. 7

Author(s):

B. Bachir Bouiadjra ◽

N. Mehnane ◽

N. Oukli

Keyword(s):

Optical Properties ◽

Density Functional ◽

Electronic Band Structure ◽

Scale Up ◽

Energy Scale ◽

First Principles Calculation ◽

Full Potential ◽

Electronic Band ◽

Electronic And Optical Properties ◽

Growth Axis

Based on the full potential linear muffin-tin orbitals (FPLMTO) calculation within density functional theory, we systematically investigate the electronic and optical properties of (100) and (110)-oriented (InN)/(GaN)n zinc-blende superlattice with one InN monolayer and with different numbers of GaN monolayers. Specifically, the electronic band structure calculations and their related features, like the absorption coefficient and refractive index of these systems are computed over a wide photon energy scale up to 20 eV. The effect of periodicity layer numbers n on the band gaps and the optical activity of (InN)/(GaN)n SLs in the both growth axis (001) and (110) are examined and compared. Because of prospective optical aspects of (InN)/(GaN)n such as light-emitting applications, this theoretical study can help the experimental measurements.

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Influence on structural, electronic and optical properties of Fe doped ZnS quantum dot: A density functional theory based study

International Journal of Quantum Chemistry ◽

10.1002/qua.26786 ◽

2021 ◽

Author(s):

Md. Abdul Momin ◽

Md. Aminul Islam ◽

Abhijit Majumdar

Keyword(s):

Density Functional Theory ◽

Optical Properties ◽

Quantum Dot ◽

Density Functional ◽

Functional Theory ◽

Electronic And Optical Properties

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Electronic and optical properties of vacancy ordered double perovskites A2BX6 (A = Rb, Cs; B = Sn, Pd, Pt; and X = Cl, Br, I): a first principles study

Scientific Reports ◽

10.1038/s41598-021-86145-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Muhammad Faizan ◽

K. C. Bhamu ◽

Ghulam Murtaza ◽

Xin He ◽

Neeraj Kulhari ◽

...

Keyword(s):

Optical Properties ◽

Band Gap ◽

First Principles ◽

Density Functional ◽

Perovskite Solar Cells ◽

Dielectric Constants ◽

Maximum Efficiency ◽

Exchange Potential ◽

Double Perovskites ◽

Electronic And Optical Properties

AbstractThe highly successful PBE functional and the modified Becke–Johnson exchange potential were used to calculate the structural, electronic, and optical properties of the vacancy-ordered double perovskites A2BX6 (A = Rb, Cs; B = Sn, Pd, Pt; X = Cl, Br, and I) using the density functional theory, a first principles approach. The convex hull approach was used to check the thermodynamic stability of the compounds. The calculated parameters (lattice constants, band gap, and bond lengths) are in tune with the available experimental and theoretical results. The compounds, Rb2PdBr6 and Cs2PtI6, exhibit band gaps within the optimal range of 0.9–1.6 eV, required for the single-junction photovoltaic applications. The photovoltaic efficiency of the studied materials was assessed using the spectroscopic-limited-maximum-efficiency (SLME) metric as well as the optical properties. The ideal band gap, high dielectric constants, and optimum light absorption of these perovskites make them suitable for high performance single and multi-junction perovskite solar cells.

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Effect of native defects on thermoelectric properties of copper iodide films

Emergent Materials ◽

10.1007/s42247-021-00190-w ◽

2021 ◽

Author(s):

Peter P. Murmu ◽

Varun Karthik ◽

Shen V. Chong ◽

Sergey Rubanov ◽

Zihang Liu ◽

...

Keyword(s):

Thermoelectric Properties ◽

Copper Iodide ◽

Native Defects

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Single-crystalline epitaxial TiO film: A metal and superconductor, similar to Ti metal

Science Advances ◽

10.1126/sciadv.abd4248 ◽

2021 ◽

Vol 7 (2) ◽

pp. eabd4248

Author(s):

Fengmiao Li ◽

Yuting Zou ◽

Myung-Geun Han ◽

Kateryna Foyevtsova ◽

Hyungki Shin ◽

...

Keyword(s):

Transition Metal ◽

Density Functional ◽

Tight Binding ◽

Crystal Form ◽

Titanium Monoxide ◽

Binding Model ◽

Functional Theory ◽

Single Crystalline ◽

First Time ◽

Lattice Matched

Titanium monoxide (TiO), an important member of the rock salt 3d transition-metal monoxides, has not been studied in the stoichiometric single-crystal form. It has been challenging to prepare stoichiometric TiO due to the highly reactive Ti2+. We adapt a closely lattice-matched MgO(001) substrate and report the successful growth of single-crystalline TiO(001) film using molecular beam epitaxy. This enables a first-time study of stoichiometric TiO thin films, showing that TiO is metal but in proximity to Mott insulating state. We observe a transition to the superconducting phase below 0.5 K close to that of Ti metal. Density functional theory (DFT) and a DFT-based tight-binding model demonstrate the extreme importance of direct Ti–Ti bonding in TiO, suggesting that similar superconductivity exists in TiO and Ti metal. Our work introduces the new concept that TiO behaves more similar to its metal counterpart, distinguishing it from other 3d transition-metal monoxides.

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Tuning the optoelectronic properties of hematite with rhodium doping for photoelectrochemical water splitting using density functional theory approach

Scientific Reports ◽

10.1038/s41598-020-78824-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Abdur Rauf ◽

Muhammad Adil ◽

Shabeer Ahmad Mian ◽

Gul Rahman ◽

Ejaz Ahmed ◽

...

Keyword(s):

Density Functional Theory ◽

Optical Properties ◽

Optical Absorption ◽

Water Splitting ◽

Density Functional ◽

Formation Energy ◽

Visible Region ◽

Photoelectrochemical Water Splitting ◽

Theory Approach ◽

Functional Theory

AbstractHematite (Fe2O3) is one of the best candidates for photoelectrochemical water splitting due to its abundance and suitable bandgap. However, its efficiency is mostly impeded due to the intrinsically low conductivity and poor light absorption. In this study, we targeted this intrinsic behavior to investigate the thermodynamic stability, photoconductivity and optical properties of rhodium doped hematite using density functional theory. The calculated formation energy of pristine and rhodium doped hematite was − 4.47 eV and − 5.34 eV respectively, suggesting that the doped material is thermodynamically more stable. The DFT results established that the bandgap of doped hematite narrowed down to the lower edge (1.61 eV) in the visible region which enhanced the optical absorption and photoconductivity of the material. Moreover, doped hematite has the ability to absorb a broad spectrum (250–800) nm. The enhanced optical absorption boosted the photocurrent and incident photon to current efficiency. The calculated results also showed that the incorporation of rhodium in hematite induced a redshift in optical properties.

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