Modeling of Thermal Effect on the Electronic Properties of Photovoltaic Perovskite CH₃NH₃PbI₃: The Case of Tetragonal Phase

Abstract

Hybrid organic-inorganic perovskites are semiconductors with disordered structures and remarkable properties for photovoltaic applications. Many theoretical investigations have attempted to obtain structural models of the high-temperature phases, but most of them are focused on the mobility of organic components and their implications in material properties. Herein we propose a set of geometric variables to evaluate the conformation of the inorganic framework at each phase of methylammonium lead iodide perovskite. We show that the analysis of these variables is required to ensure consistent structural models of the tetragonal phase. We explore the theoretical ingredients needed to achieve good models of this phase. Ab initio molecular dynamic simulation, under canonical ensemble at the experimental unit cell volume, leads to representative states of the phase. Under this scheme, PBE and van der Waals density functional approaches provide similar models of the tetragonal phase. We find that this perovskite has a highly mobile inorganic framework due to the thermal effect regardless of movement of the organic cations. Consequently, the electronic structure shows significant movements of the bands with large bandgap variations.FONDECYT of CONICYT-Chile 3150174 1150538 Ministerio de Economia y Competitividad of Spain - Comunidad de Madrid, Spain ENE2013-46624 P 2013/MAE-278

Halogen in materials design: Revealing the nature of hydrogen bonding and other non-covalent interactions in the polymorphic transformations of methylammonium lead tribromide perovskite

“…Moreover, since the organic cation in o-MAPbBr 3 is experimentally observed to be in a fixed orientation in the low temperature phase, a molecular dynamics simulation is deemed unnecessary to provide insight into the nature of the non-covalent interactions involved. Both MAPbI 3 and MAPbBr 3 have previously been explored by molecular dynamics simulations [72][73][74][75], yet insight into the underlying bonding topology is, in our view, and those of others [30], still greatly lacking. We believe that the results presented below on the equilibrium static geometries significantly enhances our current understanding of the bonding scenarios in the…”

Investigating the Tetragonal‐to‐Orthorhombic Phase Transition of Methylammonium Lead Iodide Single Crystals by Detailed Photoluminescence Analysis

“…[ 48 ] With the assumption that lattice dilation is the dominant factor for the temperature‐dependent shift of the PL maximum, [ 6,12 ] we find tensile strain values of 85–165 MPa (see Section S7 in the Supporting Information for details). However, recent studies demonstrated that the unit cell volume of the orthorhombic phase is smaller than the one of the tetragonal phase, [ 4,45,49,50 ] and thus there should be compressive strain instead of tensile strain to affect the tetragonal inclusions. Room temperature measurements showed that pressure on MAPbI 3 leads to a red shift.…”

Recent Advances in Energetics of Metal Halide Perovskite Interfaces

“…In the pursuit of developing high energy‐conversion efficiency in organic‐inorganic hybrid halide perovskites‐based optoelectronic devices, the reliable information about their electronic structures is indispensable for a deep understanding of the photon harvesting process. It has been reported that the electronic and optical properties of metal halide perovskites can be tuned by several factors, including halide substitution, substrate engineering, annealing treatments, and trap states . Note that all the perovskite films studied in this work (without mentioned fabrication method) are fabricated by spin‐coating solution process, while several reports using thermal evaporation will be marked specifically.…”