Investigation of structural, opto-electronic and thermoelectric properties of titanium based chloro-perovskites XTiCl₃ (X = Rb, Cs): a first-principles calculations

Abstract

Perovskites are a significant class of materials with diverse uses in modern technology.

A DFT investigation of lead-free TlSnX3 (X = Cl, Br, or I) perovskites for potential applications in solar cells and thermoelectric devices

“…This behaviour aligns with the results reported for other perovskites. 50,51 In contrast, TlSnCl 3 perovskite possesses a negative frequency at the M-point, suggesting that the material is not as stable as the TlSnBr 3 and TlSnI 3 perovskites. The appearance of imaginary modes in the phonon dispersion might stem from three factors: (i) potential numerical issues during the calculation, (ii) incomplete consideration of certain physical parameters when computing dynamical matrices or force constants, and (iii) inherent dynamic instabilities within the crystal structure.…”

A‐Site Cation Replacement of Hydrazinium Lead Iodide Perovskites by Borane Ammonium Ions: A DFT Calculation

“…The dielectric function ( ϵ ) is one of the vital properties for understanding the optical properties, which depends on the frequency ($${\omega }$$ ) of the incident photon. The real, imaginary part of the dielectric function (ϵ r , ϵ i ) and the complex ϵ can be calculated from the following equations (2), (3) and 4 [25–27] $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\varepsilon{} }_{r}\left(\omega \right)=1+{{2}\over{\pi }}P\int _{0}^{\infty }{{{\omega }^{{ {^\prime}}{\varepsilon{} }_{i}\left({\omega }^{{ {\prime}}}\right)}d\omega { {^\prime}}}\over{{\omega }^{{ {^\prime}}2}-{\omega }^{2}}}\hfill\cr}}$$$ $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\varepsilon{} }_{i}\left(\omega \right)=\left({{4{\pi }^{2}{e}^{2}}\over{{m}^{2}{\omega }^{2}}}\right)\sum _{x,y}\int x\left|M\right|{y}^{2}{f}_{x}\left(1-{f}_{x}\right)\delta \left({E}_{f}-{E}_{x}-\omega \right){d}^{3}K\hfill\cr}}$$$ $$$\vcent...$$…”

First-principle insight into the structural, electronic, elastic and optical properties of Cs-based double perovskites Cs2XCrCl6 (X = K, Na)

“…In order to predict the stability of the perovskite materials, the Gold-Schmidt tolerance factor and the octahedral factor ( μ = r A / r B ) were typically calculated. 34 In the case of double perovskite the average value of X (K or Na) and Cr were taken for r B . 35 The calculated values of tolerance factor and octahedral factor are displayed in Table 1 , indicating stable perovskite structures for both materials.…”