One-dimensional Anderson insulators predicted to host the bulk photovoltaic effect

0

One-dimensional Anderson insulators predicted to host the bulk photovoltaic effect
Figure 1: A light micrograph of a conventional photovoltaic cell based on polycrystalline silicon (blue crystals). Such solar cells use the photovoltaic effect to convert light into electricity. Photovoltaic devices based on the bulk photovoltaic effect could overcome some of the limitations of conventional devices. Credit: Antonio Romero/Science Photo Library

Materials in which electrons are strongly localized are promising for use in next-generation solar cells and optoelectronic devices, calculations by a RIKEN theoretical physicist and a collaborator have indicated.

Conventional photovoltaic devices such as solar cells and light detectors use a phenomenon known as the photovoltaic effect to convert light into electricity. An essential element of such devices is an interface between a material with an excess of electrons and one with a deficiency of electrons (a p–n junction). But devices based on a single p–n junction have several limitations: for example, their light conversion efficiency is capped at around 34%.

Loading...

Another effect, known as the bulk photovoltaic effect—a phenomenon whereby light generates an electrical current in materials that meet certain conditions—is attracting increasing attention because it has the potential to overcome these limitations, making it attractive for use in next-generation solar cells and light detectors.

“I’ve been working on the geometric current in solids for nearly two decades, and the photovoltaic effect is the hottest topic in my view,” says Naoto Nagaosa from the RIKEN Center for Emergent Matter Science.

Now, Nagaosa and a colleague have calculated that the bulk photovoltaic effect can occur in a one-dimensional (1D) disordered system known as a 1D Anderson insulator as long as there is sufficient coupling between electrons and particle-like vibrations known as phonons.

Loading...

The researchers used a tight-binding model with a disorder potential to study the photocurrent in a 1D chain attached to metallic leads. They found that a photocurrent flows through the system even in the presence of substantial amounts of disorder, thanks to the weak dissipation arising from electron–phonon interactions.

In agreement with recent experiments on a ferroelectric semiconductor, the bulk photovoltaic current was found to be nearly independent of the amount of disorder, as long as the disorder potential is smaller than the band gap. However, there is a characteristic dependence on bulk dissipation, which manifests as a temperature dependence of the photocurrent. At room temperature, the photocurrent can reach the value it would have in a perfectly ordered system even when the chain is very long.

“Taken together, these results imply that Anderson insulators can be promising material candidates for efficient solar cells and photodetectors,” says Nagaosa.

Loading...

In 3D Anderson insulators, the contribution of the localized states to the photocurrent should become dominant under illumination with light of frequency resonant with the band gap. Thus, it will be possible to test the new theory not only in 1D chains, but also in 3D systems.


Breaking symmetry leads to responsive organic photodetectors


More information:
Hiroaki Ishizuka et al, Theory of bulk photovoltaic effect in Anderson insulator, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2023642118

Loading...

Citation:
One-dimensional Anderson insulators predicted to host the bulk photovoltaic effect (2021, May 27)
retrieved 27 May 2021
from https://techxplore.com/news/2021-05-one-dimensional-anderson-insulators-host-bulk.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

Loading...

Stay connected with us on social media platform for instant update click here to join our  Twitter, & Facebook

We are now on Telegram. Click here to join our channel (@TechiUpdate) and stay updated with the latest Technology headlines.

Loading...

For all the latest Technology News Click Here 

 For the latest news and updates, follow us on Google News

Read original article here

Loading...
Denial of responsibility! TechiLive.in is an automatic aggregator around the global media. All the content are available free on Internet. We have just arranged it in one platform for educational purpose only. In each content, the hyperlink to the primary source is specified. All trademarks belong to their rightful owners, all materials to their authors. If you are the owner of the content and do not want us to publish your materials on our website, please contact us by email – [email protected]. The content will be deleted within 24 hours.

Leave a comment