Researchers reporting in ACS Applied Electronic Materials have fabricated an improved stretchy organic LED that releases candlelight-like light for flexible lighting and smart displays that people can comfortably use at night.

Figure 1: stretchy organic LED

Figure 1 shows that Previously, Jwo-Huei Jou and other researchers developed organic LEDs that released warm-white light, similar to that produced by candles.

However, the devices still emitted some blue wavelength light, which can interfere with sleep because it dampens the body’s production of melatonin. These devices were made of solid materials and weren’t flexible.

The backing is mica — a natural mineral with extreme temperature tolerance that can be split into bendable, transparent sheets. So, Jou, Ying-Hao Chu and colleagues wanted to develop an even better organic LED and apply it to a mica backing, creating a bendable candle-like light with a long lifespan. [1]

The researchers applied a transparent film of indium oxide and tin to a transparent sheet of mica as an anode LED that could bend 50,000 times without breaking.

Next, the team mixed the luminescent substance H, H ‘-dicarbazole-1,1′-biphenyl with red and yellow phosphorescent dyes to obtain a light-emitting layer.

This layer was then placed between the electrically conductive solutions with the anode on one side and the aluminum layer on the other side, creating a flexible organic LED.[2]

When a constant current was applied to the device, it produced a bright, warm light with even less blue wavelength emissions than natural candlelight.

Calculations showed that exposure to the LED for 1.5 hours would suppress a person’s melatonin production by about 1.6%, whereas light from a cold-white compact fluorescent lamp would suppress melatonin production by 29%.

The researchers say that the flexibility of their candlelight-like organic LED opens up the design opportunities for blue-light-free nighttime devices. [3]

References:

1. https://www.acs.org/content/acs/en/pressroom/newsreleases/2022/may/candlelight-like-glow-from-a-flexible-organic-led.html
2. https://futechie.com/the-new-flexible-organic-led-gives-off-a-comfortable-glow-like-glow/39394/
3. https://technoblender.com/new-flexible-organic-led-gives-off-a-comfortable-candlelight-like-glow/

Cite this article:

Sri Vasagi K (2022), Candlelight Spark from a Stretchy Organic LED, Anatechmaz, pp. 323