Nanoscale domain patterns and a concept for an energy harvester

TL;DR

This paper uses a phase-field model to analyze nanoscale ferroelectric domain stability and proposes a conceptual energy harvester device that converts mechanical strain into electrical energy with promising power density.

Contribution

It introduces a stability analysis of nanoscale domain patterns and presents a novel conceptual design for a ferroelectric energy harvester device.

Findings

Stripe-like domain patterns are stable at the nanoscale.

The proposed harvester can generate about 40W/m2 at kHz frequencies.

Mechanical bending induces ferroelectric switching for energy conversion.

Abstract

The current work employs a phase-field model to test the stability of nanoscale periodic domain patterns, and to explore the application of one pattern in an energy harvester device. At first, the stability of several periodic domain patterns with in-plane polarizations is tested under stress-free and electric field-free conditions. It is found that simple domain patterns with stripe-like features are stable, while patterns with more complex domain configurations are typically unstable at the nanoscale. Upon identifying a stable domain pattern with suitable properties, a conceptual design of a thin film energy harvester device is explored. The harvester is modelled as a thin ferroelectric film bound to a substrate. In the initial state a periodic stripe domain pattern with zero net charge on the top electrode is modelled. On bending the substrate, a mechanical strain is induced in the film, causing polarized domains to undergo ferroelectric switching and thus generate electrical energy. The results demonstrate the working cycle of a conceptual energy harvester which, on operating at kHz frequencies, such as from vibrations in the environment, could produce an area power density of about 40W/m2.