A candlelight-like glow from a flexible organic LED

For a special dinner or a quiet evening at home, candles set the mood. Some lighting alternatives, such as electronic candles, give off unwanted blue wavelengths that interfere with the body's rhythm. Researchers have fabricated an improved bendable organic LEDs that can be used for flexible lighting and smart displays that people can use at night.

Jwo-Huei Jou and other researchers developed organic LEDs that released warm-white light. The blue wavelength light that the devices emit can interfere with sleep because it slows the production of melatonin. Solid materials were used to make these devices.

Plastic backings have been used for other organic LEDs to make them bendable. The plastic doesn't stand up well to repeated bending. A natural mineral with extreme temperature tolerance can be split into bendable, transparent sheets. They wanted to create a bendable candle-like light with a long lifespan by applying an even better organicLED to a mica backing.

The researchers deposited a clear indium tin oxide film onto a transparent mica sheet to make the LEDs bend without breaking. The team mixed the luminescent substance with red and yellow phosphorescent dyes to create a light-emitting layer. This layer was placed between two different types of solutions, one of which had an anode on one side and another of which had an aluminum layer on the other side.

When a constant current was applied to the device, it produced a bright, warm light with less blue wavelength emissions than natural candlelight. Exposure to the light from a cold-white compact fluorescent lamp would suppress melatonin production by 29%, while exposure to the light from the LEDs would suppress melatonin production by 1.6%. The flexibility of their organic LEDs opens up design opportunities for blue-light-free nighttime devices.

More information: Tun-Hao Chen et al, Flexible Candlelight Organic LED on Mica, ACS Applied Electronic Materials (2022). DOI: 10.1021/acsaelm.2c00123 Citation: A candlelight-like glow from a flexible organic LED (2022, May 24) retrieved 24 May 2022 from https://phys.org/news/2022-05-candlelight-like-flexible.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.