3D-to-2D Transition of Anion Mobility in CsPbBr${}_3$ under Pressure

Abstract

We study the effects of hydrostatic pressure in the range 0.0--2.0 GPa on anion mobility in the orthorhombic $Pnma$ phase of CsPbBr${}_3$. Using density functional theory and the climbing nudged elastic band method, we calculate the transition states and activation energies for anions to migrate both within and between neighbouring PbBr${}_3$ octahedra. The results of those calculations are used as input to a kinetic model for anion migration, which we solve in the steady state to determine the anion mobility tensor as a function of applied pressure. We find that the response of the mobility tensor to increasing pressure is highly anisotropic, being strongly enhanced in the $(010)$ lattice plane and strongly reduced in the direction normal to it at elevated pressure. These results demonstrate the potentially significant influence of pressure and strain on the magnitude and direction of anion migration in lead--halide perovskites.

arXiv comment25 pages, 3 figures

References in corpus (8)

• Unravelling the role of vacancies in lead halide perovskite through electrical switching of photoluminescence
• Microseconds, milliseconds and seconds: deconvoluting the dynamic behaviour of planar perovskite solar cells
• Elastic softness of hybrid lead halide perovskites
• High-Throughput ab-initio Dilute Solute Diffusion Database
• Pressure induced band structure evolution of halide perovskites: a first-principles atomic and electronic structure study
• Assessing density functionals using many body theory for hybrid perovskites
• Low energy paths for octahedral tilting in inorganic halide perovskites
• Diffusivity and derivatives for interstitial solutes: Activation energy, volume, and elastodiffusion tensors