Strain-driven tunability of the optical, electronic, and mechanical properties of lead-free inorganic CsGeCl₃ perovskites

Abstract

Lead-free inorganic metal halide perovskites CsGeCl3 have recently gained prominent research interest in solar technology due to their outstanding optoelectronic properties and mechanical stability. Here, the density functional theory is considered to investigate the biaxial strain-driven (from -6% to +6%) structural configuration, mechanical stability, and optoelectronic properties of non-toxic CsGeCl3 metal halide. Optical properties such as absorption coefficient, dielectric functions, and electron loss function show that due to the biaxial strain (compressive and tensile), this material has a high absorption capacity of photons in the visible and ultraviolet regions, and that’s why it is very much suitable to apply in the solar cells and other optoelectronic energy devices. The electronic band structure shows that CsGeCl3 is a semiconductor material with a direct bandgap of 0.768 eV at the R-point. Moreover, we observed a semiconductor-to-metallic transition of the bandgap of CsGeCl3 in the presence of the compressive strain. The findings of the mechanical properties of the CsGeCl3 perovskites demonstrate that Ge could be a suitable replacement for Pb in the traditional Pb-based perovskite structures. Especially in the strain portion of -2% to +2%, the investigated metal halide perovskite (CsGeCl3) structure, Pb being replaced by Ge, shows mechanical ductility, absorption of visible and UV radiation, prominent absorption peaks, tunable bandgap value of 0.123 to 0.896 eV and thus, is very much suitable to be considered for solar photovoltaic applications.

Effect of Low to High Pressure on the Structural, Mechanical, Electrical, and Optical Properties of Inorganic Material Ca3AsBr3: An Ab Initio Investigation

“…We looked at how the presence of external stress alters the physical properties, including electronic bandgap, to define the electric characteristics of Ca 3 AsBr 3 . Understanding elastic constants, anisotropy, and moduli is essential to appreciate a compound’s potential for device construction applications fully. − On the other hand, the anticipated pressure-sensitive electrical and optical properties are crucial for comprehending the suitability of the investigated materials for optoelectronic applications. , A number of these aspects motivate us to do more theoretical research utilizing the ab initio density functional theory (DFT) procedure, a well-liked technique for forecasting new energy substances based on the electrical, mechanical, and optical properties of these compounds.…”

Room-temperature synthesis of Ag- and Mn-doped Cs2NaBiCl6 octahedrons for dye photodegradation

“…Therefore, searching for lead-free perovskites or low-lead perovskites with good stability has been one of the most popular research topics in the related fields. 3 It is noteworthy that partially or completely substituting Pb with other metal cations not only improves the stability but also eliminates the toxicity of the resulting materials, 4 based on which the replacing Pb 2+ with IVA group metal cations (e.g., Ge 2+ , Sn 2+ ), 5,6 trivalent cations (e.g., Bi 3+ , Sb 3+ ), 7 and tetravalent cations (e.g., Zr 4+ , Sn 4+ , Ti 4+ ), [8][9][10] has been explored. One of the methods for obtaining the most competitive lead-free perovskite candidate is to utilize a pair of hetero-valent cations to replace two toxic Pb 2+ central cations.…”

“…It is noteworthy that partially or completely substituting Pb with other metal cations not only improves the stability but also eliminates the toxicity of the resulting materials, 4 based on which the replacing Pb 2+ with IVA group metal cations ( e.g. , Ge 2+ , Sn 2+ ), 5,6 trivalent cations ( e.g. , Bi 3+ , Sb 3+ ), 7 and tetravalent cations ( e.g.…”