Effect of pressure on the order–disorder phase transitions of B cations in AB′_1/2 B′′_1/2O₃ perovskites

Abstract

Perovskite‐like oxides AB′1/2B′′1/2O3 may experience different degrees of ordering of the B cations that can be varied by suitable synthesis conditions or post‐synthesis treatment. In this work the earlier proposed statistical model of order–disorder phase transitions of B cations is extended to account for the effect of pressure. Depending on the composition, pressure is found to either increase or decrease the order–disorder phase transition temperature. The change in transition temperature due to pressure in many cases reaches several hundred kelvin at pressures accessible in the laboratory, which may significantly change the degree of atomic ordering. The work is intended to help in determining how pressure influences the degree of atomic ordering and to stimulate research into the effect of pressure on atomic order–disorder phase transitions in perovskites.

Pressure-Induced Band Gap Engineering of Nontoxic Lead-Free Halide Perovskite CsMgI3 for Optoelectronic Applications

“…As a result, the pressure has a major impact on the optical and electrical properties, which reveals promising qualities for photovoltaic (PV) and optoelectronic applications. Hydrostatic pressure has shown remarkable success in improving the physical characteristics of halide perovskites. − Usually, hydrostatic pressure modifies the lattice parameters, displacement of cations and anions, , rotation of octahedral cages, phase transitions, , etc. As pressure is applied to metal halides, the volume of the unit cell and the lattice constants both drop. , Recent studies have demonstrated that hydrostatic pressure can decrease the band gap in inorganic halide perovskites such as KCaCl 3 , RbYbF 3 , and CsGeI 3 , leading to an increase in conductivity.…”

“…Hydrostatic pressure has shown remarkable success in improving the physical characteristics of halide perovskites. 27 − 30 Usually, hydrostatic pressure modifies the lattice parameters, 31 displacement of cations and anions, 32 , 33 rotation of octahedral cages, 34 phase transitions, 35 , 36 etc. As pressure is applied to metal halides, the volume of the unit cell and the lattice constants both drop.…”

Tuning band gap and enhancing optical functions of AGeF3 (A = K, Rb) under pressure for improved optoelectronic applications

“…For the purpose of enhancing physical properties of halide perovskites, the application of hydrostatic pressure has demonstrated tremendous results 27 – 32 . Usually, hydrostatic pressure modifies the lattice parameters 33 , displacement of cation and anion 34 , 35 , rotation of octahedral cages 36 , phase transitions 37 , 38 , etc. In the case of metal halides, structural properties, like lattice constants and unit cell volume decrease with increasing pressure 29 , 32 .…”

Enhanced optoelectronic activity of lead-free halide perovskites KMBr3 (M = Ge, Sn) under hydrostatic pressure

“…Since pressure plays a crucial role in the determination of material properties, it is vital to investigate the selected systems under pressure in order to finetune the properties of halide perovskites, which have shown tremendous results in recent years [40][41][42][43][44][45]. The pressure applied to perovskites can alter their properties in a range of ways, including the lattice parameter [46], the displacement of cations and anions [47,48], the rotation of octahedral cages [49], phase transitions [50,51], etc For metal halides, pressure normally modifies the physical and chemical properties, such as shrinkage of lattice volume, reduction of the band gap with decreasing the lattice parameter, and enhanced optoelectronic performance [37-39, 42, 44, 45]. In recent works, CsSnCl 3 , RbSnX 3 (X = Cl, Br), AGeI 3 (A = Rb, K), AGeF 3 (A = K, Rb), and RbGeX 3 (X = Cl, Br) exhibit noticeable increments in optical absorption in the visible range under elevated pressure [17,[52][53][54][55].…”