Strain-Driven Optical, Electronic, and Mechanical Properties of Inorganic Halide Perovskite CsGeBr₃

Abstract

Of late, inorganic perovskite material, especially the lead-free CsGeBr3, has gained considerable interest in the green photovoltaic industry due to its outstanding optoelectronic, thermal, and elastic properties. In this work, we systematically investigated the strain-driven optical, electronic, and mechanical properties of CsGeBr3 through the first-principles density functional theory. The unstrained planar CsGeBr3 compound demonstrates a direct bandgap of 0.92 eV at its R-point. However, by incorporating external biaxial tensile (compressive) strain the bandgap lowering (increasing) can be tuned to this perovskite. Moreover, due to the increase of tensile (compressive) strain, a red-shift (blue-shift) behavior of the absorption-coefficient and dielectric function is found in the photon energy spectrum. Strain-induced mechanical properties also reveal that CsGeBr3 perovskites are mechanically stable and highly ductile material and can be made suitable for photovoltaic applications. The strain-dependent optoelectronic and mechanical behaviors of CsGeBr3 explored here would be beneficial for its future applications in optoelectronics and photovoltaic cells design.

Investigation of a novel inorganic cubic perovskite Ca3PI3 with unique strain‐driven optical, electronic, and mechanical properties

“…and the maximum force endurance below 0.01 eV/Å. [45,46] During the relaxation studies for ionic and structural adjustment, a limit of 10 −3 a. u. was set for the level of force convergence that was deemed acceptable. Giannozzi et al [43] employed LDA and GGA functionals to compute specific organic halides, and determined that the absolute average error exceeds 10 pm.…”

First-Principles Calculations to Investigate the Stability and Thermodynamic Properties of a Newly Exposed Lithium–Gallium–Iridium-Based Full-Heusler Compound

“…The optical properties of a superconducting substance are attractive due to its remarkable nature. They show promising results in photovoltaics and optoelectronics. , This section investigates and provides a detailed analysis of a few optical characteristics. The results are shown at pressures of 0–10 GPa for LiGa 2 Ir.…”

“…It is feasible to ascertain if a material is ductile (+ve/positive value) or brittle (−ve/negative value), employing the Cauchy pressure (C 11 − C 44 ). 23,26 In Table 3, the estimated Cauchy pressure is tabulated, and it can be observed that both compounds' computed values are positive under all applied stresses, revealing that they are ductile. With heightened pressure, materials become more ductile (see Table 3).…”

“…Additionally, ε 2 (ω) may be developed using the momentum tensors between occupied and unoccupied wave functions 23,26…”

“…This material is composed of elements Li (lithium), Ga (gallium), and Ir (iridium) and has a cubic crystal structure. Studying this material under pressure has revealed several interesting properties that have implications for a more comprehensive array of technical purposes. − Physical properties like crystal structure, thermal conductivity, and electrical conductivity are crucial parameters that determine the material’s performance in different applications, which can be predicted computationally. , The crystal structure of LiGa 2 Ir Heusler is found to be sensitive to pressure and undergoes structural transitions at specific pressures . Thermal conductivity is an essential factor that regulates the material’s ability to transfer heat and is also found to be pressure-dependent. , Similarly, the electrical conductivity of LiGa 2 Ir Heusler is sensitive to pressure and has been studied under different pressures to determine its behavior.…”