First-principles investigation of stable lead-free halide perovskite materials CsSnCl _x Br _y I_3−x−y for solar cell applications

Abstract

Perovskite solar cells based on hybrid organic-inorganic lead halide materials have attracted immense interest in recent years due to their enhanced power conversion efficiency. However, the toxic lead element and unstable property of the material limit their applications. With first-principles calculations based on density functional theory, we studied a series of ten lead-free perovskite materials made of cesium, tin, and halogen elements, chlorine (Cl), bromine (Br), and iodine (I). We found that the relative concentrations of the halogen atoms determine the crystal structures and the relative stability of the halide perovskites. Chlorine tends to increase the structural stability, while iodine plays the role of reducing the band gaps of the mixed halide perovskites. Considering the stability and the requirement of suitable band gaps, we identify that, among the ten lead-free halide perovskites, CsSnCl2I, CsSnBr2I, CsSnClBrI, CsSnClI2, CsSnBrI2, and CsSnI3 are the appropriate choices for solar cell applications.

High ionic conductivity materials Li3YBr6 and Li3LaBr6 for solid-state batteries: first-principles calculations

“…For the optimization calculations, all the atoms were allowed to move until the force on each atom was less than 0.05 eV Å −1 . A plane-wave energy cutoff of 400 eV and 7 × 7 × 7 Monkhorst-Pack grid for sampling the Brillouin zone were employed [45]. For AIMD simulations, only gamma k-point and a supercell containing eight LYB or LLaB formula units were used.…”

“…For LLaB (Li 3 LaBr 6 → 3LiBr + LaBr 3 ), the decomposition energy is 0.04 eV, it seems also a stable structure because the energy (0.04 eV) is so small. From the previous research, we know that LLaB is more stable than LLaI [45]. Because LLaI is stable [38], LLaB is expected to be stable too.…”

First-principles study of thermodynamic stability and mechanical properties of fifteen high-entropy quaternary metal disilicides

“…The chemical stability of the quaternary metal disilicides was determined by calculating the formation energy (E form ) as follows [8,33],…”