5 results on '"Khera, Ejaz Ahmad"'
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2. Computational Prediction of Structural, Optoelectronic, Thermodynamic, and Thermoelectric Response of the Cubic Perovskite RbTmCl3 via DFT‐mBJ + SOC Studies.
- Author
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Khera, Ejaz Ahmad, Nazir, Abrar, Ahmed, Zubair, Manzoor, Mumtaz, Ullah, Hamid, Ansar, Sabah, Kumar, Yedluri Anil, and Sharma, Ramesh
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THERMODYNAMICS , *THERMAL expansion , *ELECTRONIC band structure , *DEBYE temperatures , *THERMOELECTRIC materials , *SEEBECK coefficient - Abstract
Perovskite halides, owing to their environmental stability, non‐toxicity, and remarkable efficiency, are emerging as potential candidates for photovoltaic, solar cell, and thermodynamic applications. The electronic, optical, thermoelectric, and thermodynamic properties of cubic perovskite RbTmCl3 are studied using density functional theory (DFT). The electronic, optical, and thermoelectric properties are calculated both with and without spin‐orbit coupling (SOC) using the Tran and Blaha functional in the structure of the modified Becke Johnson (mBJ) exchange potential, while structural and mechanical properties are assessed using the exchange‐correlation functional calculated using the Perdew Burke Ernzerhof Generalized Gradient Approximation (PBE‐GGA). The negative formation energy (−592.39 KJ mol−1) and tolerance factor (1.17) for structural stability and current their existences in the cubic phase are found. Evaluation of the obtained data with and without SOC shows that the SOC effect causes the Tm‐d states to be shifted toward the level of Fermi, thereby decreasing the energy band gaps from 1.42 to 1.32 eV. Nevertheless, only the shift of the third variable peak to lower energies indicates the impact of SOC on optical properties. The effectiveness of RbTmCl3 in optical devices operating in the visible and ultraviolet regions is demonstrated by the exceptional absorption of light in these ranges. Using TB‐mBJ + SOC functional, the electronic band structure research reveals a direct semiconducting band gap of 1.32 eV in comparison to earlier calculations like LDA, PBE‐GGA, and TB‐mBJ. The absorption spectrum, reflectivity, extinction coefficient, refractive index, and dielectric function are displayed in addition to the electrical properties. Additionally, the quasi‐harmonic Debye model, which accounts for lattice vibrations, was used to study the corresponding volume, heat capacity, expansion of the heat coefficient, and Debye temperature of the RbTmCl3 crystal. We have calculated the thermoelectric parameters such as the Seebeck coefficient, thermal conductivity, electrical conductivity, and power factor as a function of temperature (100–900 K). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Screening the structural, optoelectronic and thermoelectric features of novel inverse perovskites X3MgNa (X= Cl, Br and I): A theoretical investigation.
- Author
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Nazir, Abrar, Khera, Ejaz Ahmad, Manzoor, Mumtaz, A. Ghfar, Ayman, Kumar, Yedluri Anil, Ullah, Hamid, and Sharma, Ramesh
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ELECTRONIC band structure , *HEAT of formation , *ENERGY levels (Quantum mechanics) , *PEROVSKITE , *CONDUCTION bands , *OPTOELECTRONICS , *ELECTRONIC spectra - Abstract
The structural, optoelectronic, and transport features of novel X 3 MgNa (X = Cl, Br, and I) antiperovskites compounds are revealed by using the density functional theory. The structural stability of all of the compounds under consideration has been verified by using the Birch-Murnaghan equations of states, which indicate that all compounds have structural stability due to ground-state energy levels being negative. The electronic band structure and TDOS results reveal that the electronic band gap of Cl 3 MgNa is 4.22 eV, Br 3 MgNa is 2.18 eV, and I 3 MgNa is zero eV. The partial density of state PDOS results demonstrate that the formation of the conduction and valence bands is due to the hybridization of Cl- 3p , Br- 4p , Na-3p, and I- 5p states. In terms of optical results, reverse perovskite with Br as a cation has shown much better optical conductivity in the ultraviolet range. Therefore, Br 3 MgNa is a potential candidate among all the compounds for optoelectronic-based applications. The Boltztrap code, which is patched with WEIN2K code, has been used to compute the thermoelectric characteristics of the examined compounds. Br 3 MgNa has a greater power factor, a high electrical conductivity, and a figure-of-merit; ZT approaches unity, indicating a promising option for thermoelectric applications. • X 3 MgNa (X = Cl, Br, and I) antiperovskites compounds were studied by FPLAPW method for photovoltaic and thermoelectric properties. • To analyze the structural,dynamical stability and thermodynamic stability by tolerance factor, phonon dispersion, cohesive energy, and enthalpy of formation. • High absorption coefficients in the ultraviolet (UV) range and low reflectivity are highly valuable for optoelectronic applications. • The Br 3 MgNa is the best material due to its high figure of merit and power factor. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. A DFT Approach to Insight on the Structural, Optoelectronic and Thermoelectric Properties of Cubic Perovskites YXO3 (X = Ga, In) for Renewable Energy Applications.
- Author
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Alrashidi, Khalid A., Dixit, Aparna, Nazir, Abrar, Khera, Ejaz Ahmad, Mohammad, Saikh, Manzoor, Mumtaz, Khan, Rajwali, and Sharma, Ramesh
- Abstract
Ternary perovskites are believed to satisfy the requirements for resolving energy shortage concerns and have the potential to be valuable materials for renewable energy production. Therefore, studies on these perovskites can prove useful for optoelectronic and thermoelectric devices applications. In the current study, DFT calculations based on the FP-LAPW technique were employed to examine the physical characteristics of YXO3 (X = Ga, In) oxide perovskite for applications in energy-efficient devices. To gain a better understanding of both materials electronic characteristics, the density of states (DOS) for each is also investigated. The bandgaps (Eg) of YGaO3 and YInO3 were found to be 3.82 and 2.33 eV, using the Trans Blaha modified Beck Johnson potential (TB-mBJ) potential. The determined formation energy and cohesive energy show that the investigated perovskites are both structurally stable in the cubic phase. Examining optical characteristics clearly shows that UV regions absorb incident light the best, indicating that the oxides under study have potential use in UV-based optical sensors and other optoelectronic devices. Investigating these materials thermoelectric characteristics is a practical way to use Boltztrap code, which is based on Boltzmann’s theory. The Seebeck coefficient at room temperature for YGaO3 is 263µV/K, whereas for YInO3, it is 207µV/K, according to the evaluation of the thermal transport parameters. Ultimately, the semiconductor properties of these materials, along with their effective thermoelectric coefficients, indicate that they are likely to be used in the development of thermoelectric gadgets and optoelectronic devices in the near future. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. First-principles calculations to investigate structural, electronic, optical and thermoelectric properties of novel double perovskite Cs2CeAgX6 (X = Cl, Br) for optoelectronic and thermoelectric applications.
- Author
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Manzoor, Mumtaz, Iqbal, Muhammad Waqas, Riaz, Shahbaz, Almutairi, Badriah S., Khera, Ejaz Ahmad, Asghar, Mazia, Ansari, Mohd Zahid, Khenata, Rabah, Bin-Omran, Saad, and Aslam, Muhammad
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VISIBLE spectra , *ELECTRONIC band structure , *OPTICAL properties , *ELECTRONIC density of states , *THERMOELECTRIC apparatus & appliances , *PHONON scattering - Abstract
The present study unveils physical characteristics, including elastic parameters, phonon dispersion, electronics, optical, and thermoelectrics behavior's novel double perovskite Cs 2 CeAgX 6 (X = Cl, Br) by performing FP-LAPW computational approach. The mechanical stability of studied compounds has been addressed rigorously, and both compounds are ductile, revealing their potential for the fabrication of optoelectronic and thermal devices. Moreover, the phonon dispersion advocated about dynamical stability of the Cs 2 CeAgX 6 (X = Cl, Br) compounds. Both studied compounds have shown a wider band gap, a clear signature of a semiconductor nature. Spin-polarized electronic band structure's outcomes as well as electronic density of states have been computed using TB-mBJ approximation. Moreover, Cs 2 CeAgBr 6 offers a reduced gap rather then Cs 2 CeAgCl 6. The photo response analysis shows that Cs 2 CeAgBr 6 can absorb various ultraviolet (UV) and visible electromagnetic radiations. Henceforth, Cs 2 CeAgBr 6 is found to be a more suitable aspirant for optoelectronic device fabrication. Regarding composites' thermoelectric behaviour, the Seebeck coefficient reflects that studied materials are hole-based semiconductors computed by the BoltzTrap code. Cs 2 CeAgCl 6 has shown a higher thermal conductivity magnitude than Cs 2 CeAgBr 6 , so It's a potential thermoelectric material devices and allied applications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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