Effects of Nonhydrostatic Stress on Structural and Optoelectronic Properties of Methylammonium Lead Bromide Perovskite

Abstract

We report synchrotron X-ray diffraction, photoconductivity, and photoluminescence investigations of methylammonium-lead-bromide (MAPbBr) under various stress conditions, supported by density-functional-theory (DFT) calculations. The properties of MAPbBr show substantial dependence on the hydrostatic conditions. While nonhydrostatic compression of MAPbBr leads to amorphization above 2.4 GPa, under quasi-hydrostatic (Ar) and hydrostatic (He) pressure, the sample remains in crystalline phases. A sequence of phase transitions between two cubic phases and orthorhombic Pnma phase is observed when using Ar, or no pressure-transmitting-medium (PTM). In helium-PTM only transitions between the two cubic structures and a new isostructural phase transition with a large volume collapse to a third cubic-phase at 2.7 GPa was observed. The photoluminescence measurements indicate a pressure-induced band gap-narrowing in the cubic phase I, and a blue-shift in the orthorhombic structure. DFT calculations illustrate that the dynamics of the organic molecules and the inorganic lattice, coupled via the N-H···Br hydrogen-bonding interactions, affect the Pb-Br distance and the bandgap evolution under pressure.

Addressing the Reliability and Electron Transport Kinetics in Halide Perovskite Film via Pulsed Laser Engineering

“…It is worth noting that the generation of residual stress during the fabrication process is induced by lattice mismatch, which also influences electronic characters and stability of the device . In the initial spin coating process, the interaction between the crystal nuclei in the precursor solution is so weak that the viscosity is not high enough to sustain the stress and the crystal nuclei in the precursor solution can move freely, as shown in Figure S1 (Supporting Information).…”

“…However, at lower laser scanning speed, the movement of cations in the perovskite crystal is promoted and concentrated at the defects and grain boundaries, leading to an uneven distribution of the potential field in the MAPbI 3 film and forming a large number of positive and negative electric centers in the film. At the same time, MAPbI 3 perovskite films will decompose to PbI 2 crystals, while MAI will decompose into CH 3 NH 2 and HI (Figure S1a, Supporting Information) . Here we focus on the (110) crystallization peak of the XRD pattern to demonstrate crystal structure changes in the MAPbI 3 perovskite film (Figure b).…”

Unusual Pressure‐Driven Phase Transformation and Band Renormalization in 2D vdW Hybrid Lead Halide Perovskites

“…Previously, a number of studies have studied the physical behavior of 3D hybrid halide perovskites under extreme hydrostatic pressures using diamond anvil cell (DAC) chamber design . These pressure studies provide a powerful tool for changing interatomic distances and bond lengths on demand, and monitor structural, physical, or chemical properties and functionalities at finite pressures.…”

Pressure-Dependent Stability of Imidazolium-Based Ionic Liquid/DNA Materials Investigated by High-Pressure Infrared Spectroscopy

“…Previous studies [26][27][28] revealed that pure ILs have an anisotropic cluster structure, and the hydrogen-bonding network can be easily disturbed by adding various materials under high-pressure conditions. Deemyad et al [29][30][31] concluded that pressure can induce superconductivity and electronic properties modification of Cu 2 I 2 Se 6 by a structural change. The electronic responses, optoelectronic properties, energy band gaps, and crystal structures of different materials, such as semiconductors [29], perovskites [30], and piezochromic materials [31], can be varied by compression.…”

“…Deemyad et al [29][30][31] concluded that pressure can induce superconductivity and electronic properties modification of Cu 2 I 2 Se 6 by a structural change. The electronic responses, optoelectronic properties, energy band gaps, and crystal structures of different materials, such as semiconductors [29], perovskites [30], and piezochromic materials [31], can be varied by compression. For example, IL-β-cyclodextrin (IL-β-CD) associated forms under low pressures can be turned to dissociated structures with the pressure increase [26].…”