Understanding the Instability of the Halide Perovskite CsPbI${}_3$ through Temperature-Dependent Structural Analysis

Abstract

Despite the tremendous interest in halide perovskites in solar cells, the reason that the all-inorganic perovskite CsPbI${}_3$ is unstable at room temperature remains mysterious. Here single-crystal X-ray diffraction and powder pair distribution function (PDF) measurements characterize bulk perovskite CsPbI${}_3$ from 100 to 295 K to elucidate its thermodynamic instability. While Cs occupies a single site from 100 to 150 K, it splits between two sites from 175 to 295 K with the second site having a lower effective coordination number, which along with other structural parameters suggests that Cs rattles in its coordination polyhedron. PDF measurements reveal that on the length scale of the unit cell, the Pb-I octahedra concurrently become greatly distorted, with one of the I-Pb-I angles approaching 82° compared to the ideal 90°. The rattling of Cs, low number of Cs-I contacts, and high degree of octahedral distortion cause the instability of perovskite-phase CsPbI${}_3$. These results provide detailed structural information that may help to engineer greater stability of CsPbI${}_3$ and other all-inorganic perovskites for use in solar cells.

21 pages including supporting information. 4 figures, 7 supporting figures, 2 supporting tables

References in corpus (6)

• New Tolerance Factor to Predict the Stability of Perovskite Oxides and Halides
• Local polar fluctuations in lead halide perovskite crystals
• What is moving in hybrid halide perovskite solar cells?
• Direct Observation of Dynamic Symmetry Breaking above Room Temperature in Methylammonium Lead Iodide Perovskite
• The Geometric Blueprint of Perovskites
• Kinetically Stable Single Crystals of Perovskite-Phase CsPbI${}_3$

Cited by in corpus (12)

• Atomistic insights into the degradation of halide perovskites: a reactive force field molecular dynamics study
• What Happens at Surfaces and Grain Boundaries of Halide Perovskites: Insights from Reactive Molecular Dynamics Simulations of CsPbI${}_3$
• Photophysics of Two-Dimensional Semiconducting Organic-Inorganic Metal-Halide Perovskites
• Mixing I and Br in Inorganic Perovskites: Atomistic Insights from Reactive Molecular Dynamics Simulations
• Post-Transition Metal Sn-Based Chalcogenide Perovskites: A Promising Lead-Free and Transition Metal Alternative for Stable, High-Performance Photovoltaics
• Structure Prediction of Ionic Epitaxial Interfaces with Ogre Demonstrated for Colloidal Heterostructures of Lead Halide Perovskites
• From latent ferroelectricity to hyperferroelectricity in alkali lead halide perovskites
• Optimizing Lead-Free Chalcogenide Perovskites for High-Efficiency Photovoltaics via Alloying Strategies
• Probing Optoelectronic Properties of Stable Vacancy-Ordered Double Perovskites: Insights from Many-Body Perturbation Theory
• Location and migration of interstitial Li ions in CsPbI${}_3$ crystals
• A Reparameterized Density Functional Tight-Binding Method for Engineering phase-stable CsPbX\textsubscript{3} Perovskites
• Data-Driven Exploration and Insights into Temperature-Dependent Phonons in Inorganic Materials