# Enhanced Piezoelectric Response in Hybrid Lead Halide Perovskite Thin Films via Interfacing with Ferroelectric PbZr$_{0.2}$Ti$_{0.8}$O$_3$

## TL;DR

This study demonstrates a over tenfold increase in piezoelectric response of MAPbI$_3$ films when interfaced with ferroelectric PZT, revealing new insights into interfacial effects and domain behavior in hybrid perovskite structures.

## Contribution

It introduces a novel interface engineering approach that significantly enhances the piezoelectric response of hybrid lead halide perovskite films.

## Key findings

- Piezoelectric coefficient $d_{33}$ increased from ~0.3 pm/V to ~4 pm/V on PZT interfaces.
- Large-scale polar domains observed on PZT, indicating long-range dipole interactions.
- Interfacial effects and screening layers influence polar domain orientation.

## Abstract

We report a more than 10-fold enhancement of the piezoelectric coefficient $d_{33}$ of polycrystalline CH$_3$NH$_3$PbI$_3$ (MAPbI$_3$) films when interfacing them with ferroelectric PbZr$_{0.2}$Ti$_{0.8}$O$_3$ (PZT). Piezo-response force microscopy (PFM) studies reveal $d_{33}^{MAPbI_3}$ values of ~0.3 pm/V for MAPbI$_3$ deposited on Au and ITO surfaces, with small phase angles fluctuating at length scales smaller than the grain size. In sharp contrast, on samples prepared on epitaxial PZT films, we observe large scale polar domains exhibiting clear, close to 90{\deg} PFM phase angles, pointing to polar axes along the film normal. By separating the contributions from the MAPbI$_3$ and PZT layers, we extract a significantly enhanced $d_{33}^{MAPbI_3}$ value of ~4 pm/V, which is attributed to the long-range dipole-dipole interaction facilitated domain nucleation. We also discuss the effect of the interfacial screening layer on the preferred polar direction.

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Source: https://tomesphere.com/paper/1702.00026