Lead-free perovskites InSnX₃(X = Cl, Br, I) for solar cell applications: a DFT study on the mechanical, optoelectronic, and thermoelectric properties

Abstract

This study aims to explore for the first time the mechanical, electronic, optical and thermoelectric properties of cubic lead-free perovskites InSnBr3 and InSnI3 to investigate their potential applications in solar cell devices. Additionally, the previously examined InSnCl3 perovskite is also included. The properties of the perovskites were determined using first-principles calculation based on the well-known Density Functional Theory (DFT) with the Generalized Gradient Approximation (GGA) functional implemented in the Quantum Espresso package. One of the most important findings was that the bandgaps of the compounds decrease and undergo an indirect-to-direct bandgap transition when Cl is replaced by Br and I. This indicates that InSnBr3 and InSnI3 perovskites are more suitable for solar cell applications. The bandgap energies for InSnCl3, InSnBr3, and InSnI3 perovskites are 0.59 eV (R→X), 0.44 eV (R→R), and 0.24 eV (R→R), respectively. The improved band gaps using the HSE06 functional are 2.35 eV, 2.13 eV, and 2.01 eV for the respective perovskites. The materials were found to possess chemical, mechanical, and thermodynamic stability as well as ductile behaviour. Furthermore, the materials exhibit remarkable optical properties, including high absorption coefficients and relatively small reflectivity. The calculated thermoelectric properties indicated high electrical conductivity and reasonable figure of merit values, making them promising candidates for the application in thermoelectric devices.

Novel vacancy-ordered RbKGeCl6 and RbKGeBr6 double perovskites for optoelectronic and thermoelectric applications: an ab-initio DFT study

“…As listed in table 1, the optimized lattice parameters of RbKGeCl 6 and RbKGeBr 6 are 10.14 Å and 10.72 Å, respectively. This observation aligns with previous reports in the literature indicating that Br-containing perovskites generally exhibit larger lattice parameters compared to their Cl-containing counterparts [24][25][26][27][28][29]. The same is also true for other perovskite compounds where the A and B cations are replaced with larger-sized cations [30][31][32][33][34].…”

Optoelectronic, thermoelectric and 3D-Elastic properties of lead-free inorganic perovskites CsInZrX6 (I, Cl and Br) for optoelectronic and thermoelectric applications

“…As seen from table 2, the calculated Poisson's ratio for CsInZrCl 6 , CsInZrI 6 and CsInZrBr 6 are 0.24, 0.21 and 0.245, respectively, which confirms the brittle nature of these materials. The brittle and ductile nature of a material can also be predicted from its Cauchy's pressure (C'): a negative C' value indicates brittle behavior while a positive one represents ductile nature of the material [27][28][29]. The Cauchy's pressure can be directly calculated using the elastic constants, i.e.…”