A comprehensive DFT study to evaluate the modulation in the band gap, elastic, and optical behaviour of CsPbBr₃ under the effect of stress

Abstract

The computational Generalized Gradient Approximations (GGA) are applied on cubic Cesium Lead Bromide (CsPbBr3) with different stress values of 0, 5, 10, and 15 GPa for a supercell with PBE exchange relationship parameters to study the structural, mechanical, and optoelectronic characteristics. This study aims to determine how pressure affects structural and electronic properties, how optical behaviour changes in reaction to electronic change, and how mechanical properties change as a result. The structure remains cubic, and there is no phase shift, but a reduction in the lattice parameters is seen. The reduction in band gap (1.900 eV) is found from 0-15 GPa and zero at 17 GPa. The partial densities of states (PDOS) of bulk CsPbBr3, Cs, Pb, and Br are also calculated. The partial density states PDOS of bulk CsPbBr3 show that in the valence band range, the sharpest observed peak is for d-states, while in the conduction region, the sharpest peak is for p-states and then for s-states. The significant variation in values of absorption, conductivity (imaginary and real), dielectric function (imaginary and real), loss function, reflectivity, and refractive index (imaginary and real) are found by applying stresses of 0, 5, 10, 15 GPa. Using the energy deformation relationship, the elastic constants are computed. From these constants, various mechanical characteristics such as the bulk modulus, shear modulus, Young modulus, and Poisson ratio are derived and discussed. Additionally, it is a good component in optoelectronic devices due to its high refractive index, absorption, reflectivity, and conductivity.

Some physical properties of K2TlAsX6 (X = Cl, Br) and CsPbBr3 semiconducting compounds

“…In the recent time Double perovskite compounds have attracted an increasing amount of attention due to their fascinating properties and possible applications [9]. Using the full potential linearized augmented plane wave (FP-LAPW) method, Munir et al [10] have investigated the equilibrium structural parameters, elastic constants and electronic and optical properties of potassium-based double perovskites K2TlAsX6 (X = Cl, Br), and found the possibility of the application of these materials in optoelectronic and renewable energy Junaid Zaidi et al [11] have evaluated the modulation in the electronic properties, elastic constants, and optical behavior of CsPbBr3 semiconducting material under the effect of stress up to 15 GPa, while very recently, Zemzemi [12] has studied theoretically the thermoelectric properties of a particular material family of metal halide cubic perovskites CsBX3 (B = Ge, Sn, Pb and X = Cl, Br, I). In the present work we tried to predict some physical properties of K2TlAsX6 (X = Cl, Br) double perovskite compounds and CsPbBr3 semiconducting compounds using the theoretical unit cell parameters and the elastic constants computed by Munir et al [10], and those of Junaid Zaidi et al [11], respectively.…”

“…Using the full potential linearized augmented plane wave (FP-LAPW) method, Munir et al [10] have investigated the equilibrium structural parameters, elastic constants and electronic and optical properties of potassium-based double perovskites K2TlAsX6 (X = Cl, Br), and found the possibility of the application of these materials in optoelectronic and renewable energy Junaid Zaidi et al [11] have evaluated the modulation in the electronic properties, elastic constants, and optical behavior of CsPbBr3 semiconducting material under the effect of stress up to 15 GPa, while very recently, Zemzemi [12] has studied theoretically the thermoelectric properties of a particular material family of metal halide cubic perovskites CsBX3 (B = Ge, Sn, Pb and X = Cl, Br, I). In the present work we tried to predict some physical properties of K2TlAsX6 (X = Cl, Br) double perovskite compounds and CsPbBr3 semiconducting compounds using the theoretical unit cell parameters and the elastic constants computed by Munir et al [10], and those of Junaid Zaidi et al [11], respectively. Theory and discussion of the results In object to determine the elastic wave velocities, the Debye temperature and the acoustic impedance of K2TlAsCl6 and K2TlAsBr6 materials, we used the unit cell parameters and the elastic constants reported by Munir et al [10], while for the Cesium Lead Bromide (CsP-bBr3) compound, we used the unit cell parameters and the elastic constants reported by Junaid Zaidi et al [11].…”

“…In the present work we tried to predict some physical properties of K2TlAsX6 (X = Cl, Br) double perovskite compounds and CsPbBr3 semiconducting compounds using the theoretical unit cell parameters and the elastic constants computed by Munir et al [10], and those of Junaid Zaidi et al [11], respectively. Theory and discussion of the results In object to determine the elastic wave velocities, the Debye temperature and the acoustic impedance of K2TlAsCl6 and K2TlAsBr6 materials, we used the unit cell parameters and the elastic constants reported by Munir et al [10], while for the Cesium Lead Bromide (CsP-bBr3) compound, we used the unit cell parameters and the elastic constants reported by Junaid Zaidi et al [11]. First we recalculate the bulk modulus B, shear modulus G, Pugh ratio (B/G), Young modulus E and the Poisson's ratio σ, then the Debye temperature θD.…”

“…To analyze the behavior of CsPbBr3 compound under the influence of external pressure, we also examined the change in some physical properties when the pressure changes between 0 and 15 GPa. The Debye temperature θD, the acoustic impedance (Z) as well as the Cauchy pressure CP of CsPbBr3 compound under high stress has been predicted using the theoretical unit cell parameters and the elastic constants computed by Junaid Zaidi et al [11], and the previous procedure. Under pressure, the Cauchy pressure CP has been written CP = C12 -C44 -2p [24,25], where p is the pressure.…”

“…Some Physical Properties Under Pressure Up to 15 GPa For CsPbBr3 Semiconducting Compound, * From Ref[11] …”