Structural, electronic, optical and elastic properties of the cubic perovskite PbHfO3 through modified Becke–Johnson potential (original) (raw)
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East European journal of physics, 2023
Lead halide perovskites have attracted considerable attention as one of the most promising materials for optoelectronic applications. The structural, electronic, and optical properties of the cubic perovskite CsPbF3 were studied using density functional theory in conjunction with plane waves, norm-conserving pseudopotentials, and Perdew-Berg-Erzenhof flavor of generalized gradient approximation. The obtained structural parameters are a good agreement with the experimentally measured and other's theoretically predicted values. The obtained electronic band structure revealed that cubic CsPbF3 has a direct fundamental band gap of 2.99 eV at point R. The calculated energy band gaps at the high symmetry points agree with the other available theoretical results. The GW method is adapted to correct the underestimated fundamental energy gap value to 4.05 eV. The contribution of the different bands was analyzed from the total and partial density of states. The electron densities show that Cs and F have strong ionic bonds, whereas Pb and F have strong covalent bonds. The optical properties of CsPbF3 were calculated using the density functional perturbation theory and Kramers-Kronig relations. The wide and direct bandgap nature and the calculated optical properties imply that cubic CsPbF3 can be used in optical and optoelectronic devices for high frequencies visible and low frequencies ultraviolet electromagnetic radiation.
Indonesian Journal of Chemistry
This study reports for the first time the theoretical prediction of structural, electronic, elastic and optical properties of cubic BaLiCl3, BaLiBr3, and BaLiI3 perovskites. The corresponding properties of the well-known BaLiF3 are also theoretically investigated. Density Functional Theory (DFT) using the Generalized Gradient Approximation (GGA) was implemented within the Quantum Espresso package to investigate the properties of the perovskites. The results revealed that BaLiX3 (X = F, Cl, Br, and I) are in ionic crystal forms with optimized lattice parameters of 4.04, 4.90, 5.21, and 5.66 Å, respectively. The minor band gaps were found to be 6.62 eV (Γ→Γ), 4.29 eV (R→Γ), 3.50 eV (R→Γ), and 2.58 eV (R→Γ) for the respective compounds. The investigation of their elastic properties indicated that these perovskites are all mechanically stable, while only BaLiBr3 and BaLiI3 are malleable. Finally, the studied perovskites exhibit excellent optical properties, including low reflectivity an...
AIP Advances, 2022
A comparative study on mechanical, thermodynamic, electronic, and optical properties has been performed on various compounds having an ABO 3 , where A = Ba, Ca, Sr and B = Ce, Ti, Zr, perovskite structure using first-principles calculations. These materials' properties have been thoroughly investigated for their ground states under the same computational parameters. The computed lattice parameters in the ground state agreed with other theoretical studies. Elastic moduli, ductility or brittleness, elastic anisotropy, mechanical stability, and stiffness of solid materials are studied. Enthalpy (H), entropy (S), and free energy (F) were reported from the vibrational properties of the materials. The temperature-dependent heat capacity and Debye temperature are investigated. The electronic band structure as a function of energy, of different perovskite structures at the ground state, is also studied. From this study, the ABO 3 perovskite has emerged as the most promising material for applications in optoelectronics, photonics, and mechanical and thermoelectric devices.
Journal of Physics and Chemistry of Solids, 2024
In recent years, inorganic perovskite materials have garnered significant attention in solar technology due to their outstanding structural, optical, mechanical, and electronic properties. A comprehensive investigation, employing first-principles density-functional theory, was conducted to assess the impact of compressive and tensile strain on the optical and electrical properties of cubic perovskite Sr 3 PBr 3. The unstrained Sr 3 PBr 3 exhibits a direct bandgap of 1.528 eV/2.32 eV with PBE/HSE functions at the Γ point. Under compressive strain, the bandgap decreases (1.23 eV at − 4% strain), leading to a redshift in the absorption coefficient spikes, while tensile strain results in a slight bandgap increase (1.723 eV at +4 % strain) and a blueshift in absorption coefficient spikes. Total density of states was computed as 18.75 and 1.60 electrons/eV at VB and CB without strain. The value of static dielectric constant was measured as 5.24. The initial critical point of dielectric constant, large absorption peak, and maximum loss function were calculated at 1.47, 7.28, and 9.15 eV without strain. The material demonstrates excellent light absorption in the range of visible light, aligning with its electronic properties. The Sr 3 PBr 3 perovskite is therefore thought to be perfect for usage in solar cells for the generation of power and light control.
Structural, elastic and thermo-electronic properties of paramagnetic perovskite PbTaO 3
Self-consistent ab initio calculations with highly precise spin-polarised, density functional theory (DFT) have been performed for the first time, to study the structural stability, mechanical and magneto-electronic properties of cubic perovskite PbTaO 3. The DFT as well as the analytically calculated values of tolerance factor, in addition to stable-phase optimization, mechanical and elastic properties show stability of the present material in the cubic phase with a reasonably stiff nature and ductile properties. The symmetric spin-polarised band structure of both the spin (up and down) channels reveals zero spin polarisation at the Fermi level. Moreover, the insignificant total and individual spin magnetic moments of adjacent atoms and magnetic susceptibility calculations via the post-DFT treatment predict the paramagnetic nature of the material. Based on results of the present study, the paramagnetic metal PbTaO 3 material is considered a promising candidate in designing new electrode materials.
arXiv (Cornell University), 2023
In the present paper, the electronic, structural, thermodynamic, and elastic properties of cubic P bGeO 3 perovskite oxide are presented and computed using the WIEN2k code. The structural properties have been evaluated and they are in good agreement with the theoretical and experimental data. A phonon dispersion is made and it reveals that the cubic P bGeO 3 perovskite is dynamically stable. In addition, the electronic properties of P bGeO 3 shows an opening gap energy, meaning a semiconductor behavior with an indirect band gap equal to 1.67 eV. Moreover, the obtained elastic constants of cubic P bGeO 3 satisfy Born's mechanical stability criteria, and this indicates that our compound behaves as a stable ductile material. The temperature-pressure effects on thermodynamic parameters are investigated using the Gibbs2 package. Finally, based on the obtained results about the cubic P bGeO 3 perovskite properties, we assume that this compound will have potential applications.
RSC Advances, 2022
Inorganic metal-halide cubic perovskite semiconductors have become more popular in industrial applications of photovoltaic and optoelectronic devices. Among various perovskites, lead-free materials are currently most explored due to their non-toxic effect on the environment. In this study, the structural, electronic, optical, and mechanical properties of lead-free cubic perovskite materials FrBX 3 (B ¼ Ge, Sn; X ¼ Cl, Br, I) are investigated through first-principles density-functional theory (DFT) calculations. These materials are found to exhibit semiconducting behavior with direct bandgap energy and mechanical phase stability. The observed variation in the bandgap is explained based on the substitutions of cations and anions sitting over B and X-sites of the FrBX 3 compounds. The high absorption coefficient, low reflectivity, and high optical conductivity make these materials suitable for photovoltaic and other optoelectronic device applications. It is observed that the material containing Ge (germanium) in the B-site has higher optical absorption and conductivity than Sn containing materials. A systematic analysis of the electronic, optical, and mechanical properties suggests that among all the perovskite materials, FrGeI 3 would be a potential candidate for optoelectronic applications. The radioactive element Fr-containing perovskite FrGeI 3 may have applications in nuclear medicine and diagnosis such as X-ray imaging technology.
International Journal of Energy Research, 2020
Recently, Organometallic halide based perovskites have emanated as an auspicious candidate as a solar cell absorber layer. In this article, we have explored the fundamental properties such as structural, electronic, optical, elastic, and thermoelectric parameters of CH 3 NH 3 PbBr 3 through first-principles calculations, because it has accomplished the entire criterion to use in photovoltaic and thermoelectric applications. We have used full-potential linearized augmented plane wave method (FP-LAPW) within DFT and implemented in Wien2k. The generalized gradient approximation (GGA) parameterized by Wu-Cohen (WC) has been used to optimize the lattice parameter, while for band gap calculations different exchange-correlation potentials (LDA/GGA) have been used. The band gap up to 2.26 eV has been achieved by doing some appropriate changes in the parameter of TB-mBJ exchange-correlation potential. The nature of band gap is direct and exist at R (0.5 0.5 0.5) symmetry point of the Brillouin zone. All the optical spectral response between 2 and 5 eV is due to the transition of Br 5p with little contribution Pb 5s orbital electrons of VBM to Pb 6p orbitals in CBM and a minor contribution of second band gap components also incorporate. As well as, a high absorption coefficient shows that it may be strongly applied in photovoltaic devices. The orientation of organic cations (CH 3 NH 3) + has no considerable impact on the band structure formation. To render a solid foundation about the application in the thermoelectric device up to the high-temperature region, the thermoelectric parameters have been discussed at optimal carrier concentration and definite temperature range. The measurement of elastic constants, B/G and Poisson's ratio indicates the ductile nature of CH 3 NH 3 PbBr 3. To the best of my knowledge, most of the investigations have been discussed first time for this material.
Investigation into the Crystal Structure of the Perovskite Lead Hafnate, PbHfO3
Acta Crystallographica Section B Structural Science, 1998
The room-temperature crystal structure of the perovskite lead hafnate PbHfO3 is investigated using both lowtemperature single crystal X-ray diffraction (Mo Kc~ radiation, ~. = 0.71069 A) and polycrystalline neutron diffraction (D1A instrument, ILL, ~ = 1.90788 A,). Single crystal X-ray data at 100 K: space group Pbam, a = 5.856 (1), b = 11.729 (3), c = 8.212 (2) A, V = 564.04 A. 3 with Z = 8,/z = 97.2 mm -t, F(000) = 1424, final R = 0.038, wR = 0.045 over 439 reflections with F >1.4or(F). Polycrystalline neutron data at 383 K: a = 5.8582 (3), b = 11.7224 (5), c = 8.2246 (3)A, F = 564.80 A 3 with X 2 = 1.62. Although lead hafnate has been thought to be isostructural with lead zirconate, no complete structure determination has been reported, as crystal structure analysis in both these materials is not straightforward. One of the main difficulties encountered is the determination of the oxygen positions, as necessary information lies in extremely weak l = 2n + 1 X-ray reflections. To maximize the intensity of these reflections the X-ray data are collected at 100 K with unusually long scans, a procedure which had previously been found successful with lead zirconate. In order to establish that no phase transitions exist between room temperature and 100 K, and hence that the collected X-ray data are relevant to the room-temperature structure, birefringence measurements for both PbZrO3 and PbHfO3 are also reported.
Structural and optoelectronic properties of cubic perovskite RbPbF3
The structural and optoelectronic properties of cubic perovskite RbPbF3 are calculated using all electrons full potential linearized augmented plane wave (FP-LAPW) method. The calculated lattice constant is in good agreement with the experimental result. The calculated band structure shows a direct band gap of 3·07 eV. The contribution of different bands is analysed from the total and partial density of state curves. We identified hybridization of Pb s, Pb p states with F p states in the valence bonding region. Calculations of the optical spectra, viz., the dielectric function, optical reflectivity, absorption coefficient, real part of optical conductivity, refractive index, extinction coefficient and electron energy loss are performed for the energy range of 0–30 eV. Based on the direct bandgap, as well as other optical properties of the compound, it is predicted that this material is useful for vacuum-ultraviolet-transparent (VUV-transparent) applications.