Caloric Effects in Methylammonium Lead Iodide from Molecular Dynamics Simulations

TL;DR

This study uses molecular dynamics simulations to investigate caloric effects in methylammonium lead iodide, revealing electrocaloric and mechanocaloric responses at room temperature driven by molecular cation rearrangements.

Contribution

First-principles based molecular dynamics simulations demonstrate caloric effects in MAPbI$_3$, highlighting potential for strain and doping enhancements.

Findings

MAPbI$_3$ exhibits electrocaloric and mechanocaloric effects at room temperature

Molecular cation rearrangement drives the caloric responses

Strain engineering and doping can enhance caloric effects

Abstract

Organic-inorganic hybrid perovskite architecture could serve as a robust platform for materials design to realize functionalities beyond photovoltaic applications. We explore caloric effects in organometal halide perovskites, taking methylammonium lead iodide (MAPbI$_3$) as an example, using all-atom molecular dynamics simulations with a first-principles based interatomic potential. The adiabatic thermal change is estimated directly by introducing different driving fields in the simulations. We find that MAPbI$_3$ exhibits both electrocaloric and mechanocaloric effects at room temperature. Local structural analysis reveals that the rearrangement of molecular cations in response to electric and stress fields is responsible for the caloric effects. The enhancement of caloric response could be realized through strain engineering and chemical doping.