Impact of Surface Adsorbates and Dimensionality on Templating of Halide Perovskites

TL;DR

This study uses atomic simulations to explore how surface adsorbates and layer thickness influence phase transitions and dynamics in 2D halide perovskites, revealing a design mechanism for property tuning.

Contribution

It provides detailed atomic-scale insights into how linker molecules and layer number affect phase behavior in 2D halide perovskites, a previously less understood aspect.

Findings

Layer proximity to linkers causes distinct phase transitions.

Transitions occur over a temperature range influenced by layer thickness.

Layer engineering enables tuning of perovskite dynamics and phase behavior.

Abstract

Two-dimensional (2D) halide perovskites (HPs) are promising materials for various optoelectronic applications, yet a comprehensive understanding of their dynamics is still elusive. Here, we offer insight into the dynamics of prototypical 2D HPs based on MAPbI$_3$ as a function of linker molecule and the number of perovskite layers using atomic scale simulations. We show that the layers closest to the linker undergo transitions that are distinct from those of the interior layers. These transitions can take place anywhere between a few tens of Kelvin below to more than 100 K above the cubic-tetragonal transition of bulk MAPbI$_3$. In combination with the thickness of the perovskite layer this enables one to template phase transitions and tune the dynamics over a wide temperature range. Our results thereby reveal the details of an important and generalizable design mechanism for tuning the properties of these materials.