Optoelectronic and transport properties of Rb/ Cs ₂ TeI ₆ defective perovskites for green energy applications

Abstract

Lead content in perovskite solar cells and other applications is toxic for human health and environment. Therefore, the search alternate materials are required of present era. In this article, we presented physical properties of Rb/Cs 2 TeI 6 defective perovskites for possible solar cell and thermoelectric applications. These compounds were found to be stable in perovskite structure. The band gaps were calculated in close contact to experiments. The optical properties were computed in term of dielectric function, refractive index and optical conductivity. These properties explored suitability of Rb/Cs 2 TeI 6 perovskites for solar cell applications. Also, the high figure of merit (0.687 for Rb 2 TeI 6 and 0.682 for Cs 2 TeI 6 at 1000 K) confirmed position of these compounds in family of efficient thermoelectric materials.

Inorganic Cs2TeX6 (X = Cl, Br, I) Lead-Free Vacancy-Ordered Double-Perovskite Absorber-Based Single-Junction Solar Cells with a Higher Efficiency of ∼24%: Theoretical Insights

“…A negative value of Δ H f indicates that the reaction is exothermic. Further, a few reports have already shown the stable synthesis possibilities of our considered systems through the formation energy calculation (Cs 2 TeCl 6 , Cs 2 TeBr 6 , and Cs 2 TeI 6 ). Here, we also calculated the Δ H f for the Cs 2 TeX 6 systems, and the corresponding values are presented in Table .…”

“…Our results are also in good agreement with earlier reports. For Δ H f calculation, we used the following equation ,, where the ground-state energies of the A 2 BX 6 systems and atoms A, B, and X (in bulk form) are denoted as E Total (A 2 BX 6 ), E A Bulk , E B Bulk , and E X Bulk , respectively. The negative value of Δ H f reflects the practical synthesis possibilities (thermodynamical stability) of all three systems.…”

“…Our results are also in good agreement with earlier reports. For ΔH f calculation, we used the following equation 62,63,65…”

Effect of hydrostatic pressure on opto-electronic, elastic and thermoelectric properties of the double perovskites Rb₂SeX₆(X=Cl,Br): a DFT study

“…The Figure reveals that the explored double perovskite materials have high refractive index in the 3-4 eV photon energy range, indicating that they are more appropriate for visible area operation [32]. Since the materials refractive index values are greater than unity at all hydrostatic pressure values, this indicates the materials' transparent behavior [33].…”

“…To determine a material's brittleness and ductility, Poisson's ratio can be applied. The term "ductile" refers to a material with a ν greater than 0.26, in contrast to "brittle" [10,33,41]. When pressure is applied, the two materials have ν values greater than 0.26, suggesting that they are ductile.…”