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Photonics design theory enhancing light extraction efficiency in quantum dot light emitting diodes

Othman, Diyar Mousa, Weinstein, Julia, Lyu, Quan and Hou, Bo ORCID: https://orcid.org/0000-0001-9918-8223 2022. Photonics design theory enhancing light extraction efficiency in quantum dot light emitting diodes. Journal of Physics: Materials 5 (4) , 044009. 10.1088/2515-7639/ac9e77

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Abstract

The external quantum efficiency (EQE) of quantum dot light emitting diodes (QLEDs) needs improvement for more power-efficient devices. One of the main limitations is the low light extraction efficiency (LEE). Generally, only 20% of the light that is generated inside the emissive layer makes its way out of the device into air, with the rest being lost to waveguide and substrate modes and surface plasmon polaritons. Different photonics structures have been previously tested to help extract the light that is trapped inside the device. Here we report a photonics design which is a combination of nanopillars and grating structures for improving the LEE of QLEDs. The effect of changing the nanopillar height, radius and material has been studied. It was found that ZnO nanopillars of 500nm pitch, 200nm height and 400nm width alongside 150 nm width and pitch grating structure can increase the light extraction efficiency at 460 nm by 50% and at 640 nm by 20%. It was also found that different materials can help extract light at different wavelengths. TiO2 nanopillars increased the extraction efficiency at ∼590nm region which was not observed by the other materials. As around 19% of the world's electricity consumption is due to lighting applications, increasing the LEE can significantly reduce the power consumption.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Publisher: IOP Publishing
ISSN: 2515-7639
Funders: EPSRC
Date of First Compliant Deposit: 1 November 2022
Date of Acceptance: 28 October 2022
Last Modified: 22 Jan 2023 09:59
URI: https://orca.cardiff.ac.uk/id/eprint/153885

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